Redescription and Morphometric Analysis of Isorineloricaria (Siluriformes: Loricaridae)
by
Clifton Keith Ray
A thesis submited to the Graduate Faculty of
Auburn University
in partial fulfilment of the
requirements for the Degree of
Master of Science
Auburn, Alabama
December 13, 2010
Keywords: Loricariidae, Isorineloricaria, Hypostomus,
Aphanotorulus, Squaliforma, catfish
Copyright 2010 by Clifton Keith Ray
Approved by
Jonathan W. Armbruster, Chair, Asociate Profesor of Biological Sciences
Craig Guyer, Profesor of Biological Sciences
Steven L. Powers, Asistant Profesor of Biology, Roanoke College
ii
Abstract
In this study, the genus Isorineloricaria Isbr?cker 1980 is resurrected and
redescribed. The complex history of the genus is reviewed. Isorineloricaria is diagnosed from
Hypostomus by an elongated caudle peduncle, elongate hypertrophied breeding odontodes on
nuptial males, central buccal papila enlarged or multiple buccal papilae and from most
Hypostomus by their lighter background coloration. The species of Isorineloricaria are
redescribed and diagnosed; Plecostomus annae and Hypostoma squalinum are placed in the
synonymy of I. emarginata; Plecostomus biseriatus, P. scopularis, and P. virescens are placed in
the synonymy of I. horrida; Plecostomus winzi is placed in the synonymy of I. tenuicauda, and
one new species is described from the Apure River basin of Venezuela. Speceis are largely
alopatric and separated by color patern. Species recognized as taxonomicaly valid are: I.
ammophila from the Apure and Orinoco Rivers in Venezuela; I. emarginata from the lower
Amazon River and it?s tributaries; I. gomesi from Jaguaribe River, Cear? state, Brazil; I. horrida
from the upper Amazon River, including the mainstem, Rio Napo, Rio Mara?on, Rio Ucayali,
Rio Juru?, Rio Purus, and Rio Madiera; I. phrixosoma from the Rio Ucayali, Peru; I.
spinosisima from the Guayas River basin, Ecuador; I. tenuicauda from the Magdalena River
basin in Colombia; I. unicolor from from upper Amazon tributaries of Bolivia, Brazil, Colombia,
Ecuador, and Peru; I. vilarsi from the Maracaibo basin in northwestern Venezuela and extreme
eastern Colombia; Isorineloricaria n. sp. ?Apure? is described from the Apure and Orinoco
Rivers in Venezuela. Photos of specimens and range maps are updated, and biogeorgaphic
iii
paterns and their relationships with hypothesized geologic events across the South American
continent are also discussed. During the middle to late Miocene, the vicariant events that divided
the Magdalena and Maracaibo basins from the Amazonas and Orinoco rivers were very
important in the evolution of Isorineloricaria, alowing for the rise of several of the taxa sen in
the region. Furthermore, the rise of the Andes may have alowed the invasion of the piedmont
areas by the smaler members of Isorineloricaria, such as I. ammophila, I. phrixosoma, and I.
unicolor.
iv
Acknowledgments
Lots of people deserve thanks for the supporting me through this work. First I would like
to thank my advisor, Jon Armbruster, for his guidance, patience, and kindnes. I would also like
to say thank you to Craig Guyer and Steven Powers, who were on my commite and gave me
greater insight to my research. The following people showed me every kindnes in my travels
and research at other institutions, and their contribtions to this work cannot be overlooked:
Barbra Brown, American Museum of Natural History; Mark Sabaj P?rez and Kyle Luckenbil,
Academy of Natural Sciences Philadelphia; Mary Anne Rogers and Leo Smith, Field Museum
of Natural History; Jefrey Wiliams, Smithsonian National Museum of Natural History, James
Maclaine, Brithish Museum of Natural History; Michael Retzer, Illinois Natural History Survey;
Karsten Hartle, Harvard University Museum of Comparative Zoology; Paulo Buckup, Museu
Nacional Rio de Janeiro; Osvaldo Oyakawa, Museu de Zoologia da Universidade de S?o Paulo;
Helmut Welendorf, Naturhistorishche Museum Wien.
I would personaly like to thank my labmates: Marcelo Melo, Nathan Lujan, Ricardo
Bentancour, Lesley deSouza, Shobnom Ferdous, Dave Werneke, and Milton Tan for their
insights, discussions, and motivation. I would further like to thank Marcelo Melo for sharing
valuable funding for museum research that greatly aided in my research. I have to thank Donald
Taphorn for his help in expanding my knowledge of South American ichthyofauna and for his
comments on parts of this manuscript.
v
Tyler Mosely, Emily Hartfield, and Hilary Register kept me blisfully distracted with
fieldwork and projects to fil a lifetime. For that I am forever gratefull.
I want to say thanks to my family and friends for their encouragement and support
through al the years, and for always having open ears, open hearts, and open minds. Finaly, I
want to thank my wife Britney. Without your patience and understanding I would not have been
able to finish this work. Sorry I did not include your ?Hypostomus plecostomus hypostomus.?
Maybe next time.
vi
Table of Contents
Abstract.........................................................................................................................................ii
Acknowledgments........................................................................................................................iv
List of Tables.............................................................................................................................vii
List of Figures..............................................................................................................................ix
Introduction...................................................................................................................................1
Taxanomic History of Genera.............................................................................................2
Taxanomic History of Species............................................................................................2
Phylogenetics......................................................................................................................4
Materials and Methods..................................................................................................................6
Isorineloricaria...................................................................................................................8
Isorineloricaria ammophila (Armbruster and Page 1996)...............................................11
Isorineloricaria n. sp. ?Apure? New Species....................................................................13
Isorineloricaria emarginata (Valenciennes 1840)...........................................................17
Isorineloricaria gomesi (Fowler 1941).............................................................................20
Isorineloricaria horrida (Kner 1854)...............................................................................22
Isorineloricaria phrixosoma (Fowler 1940).....................................................................25
Isorineloricaria spinosisima (Steindachner 1880)..........................................................27
Isorineloricaria tenuicauda (Steindachner 1878).............................................................29
Isorineloricaria unicolor (Steindachner 1908).................................................................32
vii
Isorineloricaria vilarsi (L?tken 1874).............................................................................35
Results and Discussion...............................................................................................................38
Biogeography....................................................................................................................38
Literature Cited...........................................................................................................................41
Material Examined......................................................................................................................46
vii
List of Tables
Table 1: Selected morphometrics of Isorineloricaria n. sp. ?Apure? and I. emarginata ...........76
Table 2: Selected morphometrics of Isorineloricaria horrida and I. spinnosisima .................77
Table 3: Selected morphometrics of Isorineloricaria tenuicauda and I. vilarsi ......................78
Table 4: Selected morphometrics of Isorineloricaria ammophila and I. unicolor ....................79
Table 5: Selected morphometrics of Isorineloricaria gomesi and I. phrixosoma .....................80
ix
List of Figures
Figure 1: Range of Loricariidae (from Armbruster 2004)..........................................................55
Figure 2: Diagram of selected measurements, adapted from Boeseman (1968) and Armbruster
and Page (1996)...........................................................................................................56
Figure 3: Selected head measurements, adapted from Boeseman (1968) and Armbruster and Page
(1996)...........................................................................................................................57
Figure 4: Illustration of caudal fin width measurement, adapted from Boeseman (1968) and
Armbruster and Page (1996)........................................................................................57
Figure 5: Results of the PCA of the species of Isorineloricaria.................................................58
Figure 6: Bivariate Fit of Snout-nares Wd. By Interorbital Wd. Red crosses- Isorineloricaria
horrida, Blue squares- I. emarginata...........................................................................59
Figure 7: Bivariate Fit of Caudal Peduncle Dp. By Head L., black circles represent I.
spinosisima, red squares represent al other Isorineloricaria (except I. ammophila and
I. unicolor) ..................................................................................................................59
Figure 8A-B: A. Ventral view of mouth of Isorineloricaria gomesi, ANSP 69409, ilustrating
the large central buccal papila characteristic of most memebers of Isorineloricaria.
B. Ventral view of mouth of I. ammophila, AUM 22659, ilustrating multiple buccal
pappilae found in I. ammophila and I. unicolor............................................................60
Figure 9: Dorsal, lateral, and ventral views of Isorineloricaria ammophila, AUM 22659........61
Figure 10: Dorsal and ventral views of Isorineloricaria n. sp. ?Apure?, INHS 35685, 269.11mm
SL...............................................................................................................................62
x
Figure 11: Lateral view of Isorineloricaria n. sp. ?Apure?, INHS 35685, 269.11mm SL..........63
Figure 12: Dorsal, lateral, and ventral views of Isorineloricaria emarginata, MZUSP 97217,
227mm SL .................................................................................................................64
Figure 13: Dorsal, lateral, and ventral views of Isorineloricaria gomesi, ANSP 69409 (holotype),
141.3mm SL...............................................................................................................65
Figure 14: Dorsal, lateral, and ventral views of Isorineloricaria horrida, AUM 42001............66
Figure 15 A-C: Ventral (A), dorsal (B), and lateral (C) views of Isorineloricaria phrixosoma,
ANSP 68650, 109.5mm SL ......................................................................................67
Figure 16: Dorsal, lateral, and ventral views of Isorineloricaria spinosisima, BMNH
1898.11.4.32 (syntype of Plecostomus festae), 357.6 mm SL ..................................68
Figure 17: Lateral, dorsal, and ventral views of Isorineloricaria tenuicauda, MSNG 8856
(syntype) ..................................................................................................................69
Figure 18: Lateral, dorsal, and ventral view of Isorineloricaria unicolor, ZMA 116640
(Aphanotorulus frankei holotype), 105.4mm SL .......................................................70
Figure 19: Dorsal, lateral, and ventral views of Isorineloricaria vilarsi, USNM 121031,
301.5mm SL ...............................................................................................................71
Figure 20: Range map of Isorineloricaria ammophila and I. unicolor. Circles represent I.
ammophila, squares represent I. unicolor. Open shapes represent type localities. From
Armbruster (2008) .....................................................................................................72
Figure 21: Range map of Isorineloricaria n. sp. ?Apure?, I. gomesi, I. phrixosoma, I.
spinosisima, I. tenuicauda, and I. vilarsi. Squares represent Isorineloricaria n. sp.
?Apure?, stars represent I. gomesi, X represents I. phrixosoma, circles represent I.
squaliforma, diamonds represent I. tenuicauda, and triangles represent I. vilarsi. Open
shapes represent type localities ...................................................................................73
xi
Figure 22: Range map of Isorineloricaria emarginata...............................................................74
Figure 23: Range map of Isorineloricaria horrida. Type locality indicated by open square.....75
1
Introduction
With just over 800 valid species, the family Loricariidae (suckermouth armored
catfishes) is the largest catfish family in the world. Its members are restricted to freshwater
habitats in Neotropical South America, Panama, and Costa Rica (Fig. 1) (Armbruster, 2004;
Nelson, 2006). The genus Hypostomus, with over 130 valid species, is a complex group with
a complex history. Currently, Hypostomus is recognized as either a single genus
(Armbruster, 2004) or as six (Isbr?cker, 2001). Three of Isbr?cker?s genera (Aphanotorulus,
Isorineloricaria, Squaliforma) were recognized as the H. emarginatus species group by
Armbruster (2004). Molecular data (Montoya-Burgos, 2003), and a more recent analysis of
Armbruster?s data (Armbruster, 2008), suggests that the H. emarginatus species group is
monophyletic, and likely should be recognized as a genus separate from the rest of the
Hypostomini, and I herein recognize Isorineloricaria as a valid genus. The species of
Isorineloricaria are unusual in having a white to light tan background color with dark spots,
the presence of hypertrophied odontodes on the bodies of nuptial males, relatively to
extremely elongate caudal peduncles, and a large central or multiple buccal papila.
Species of Isorineloricaria are generaly found over sand or gravel in high gradient
portions of piedmont streams. The range includes Trans-Andean streams such as the
Magdalena and Guayas rivers and the Lake Maracaibo drainage, and major cis-Andean
streams such as the Orinoco, Esequibo and Amazon basins.
2
Taxonomic History of Genera: The genus Hypostomus was most thoroughly
reviewed by Boeseman (1968). In his work, he reviewed the generic name Hypostomus,
tracing back the earliest descriptions of the members of this genus. Gronovius first
published the generic name of Plecostomus in 1754. Its subsequent use continued until
1954, when it was determined that Gronovius? work often included the use of trinomials,
thus making it invalid. Other authors, prior to Linnaeus, who also published the name
Plecostomus, published it in invalid works based on our current system of nomenclature.
Linnaeus incorrectly included Plecostomus plecostomus in the genus Acipenser (sturgeons),
where it remained for some time. The next generic name used for any species in the genus
was Hypostomus by Lac?p?de in 1803, making it the valid genus.
Isorineloricaria was described by Isbr?cker (1980) for Plecostomus festae and P.
spinosisimus, and Isbr?cker suggested that the two species might be synonymous. Isbr?cker
did not provide a detailed diagnosis, suggesting that a future paper would provide more
detail, but no further work was published. Isbr?cker and Nijsen (1982) described the genus
Aphanotorulus based on two specimens of a putatively new species A. frankei.
Aphanotorulus was diagnosed based on the presence of numerous buccal papilae.
Squaliforma was described by Isbr?cker & Michels (2001; in Isbr?cker et al., 2001), yet no
objective diagnosis was provided for Squaliforma.
Armbruster (2004) found Aphanotorulus, Isorineloricaria, and Squaliforma to be
nested within Hypostomus. He placed al three genera into the synonymy of Hypostomus,
but suggested that the group could be found to be a single, distinct genus.
Taxonomic History of Species: Hypostomus emarginatus was the first described
species, proposed by Valenciennes in Cuvier and Valenciennes (1840) from a dried
3
specimen obtained from the Amazon River (though the specific location was not recorded).
The next species described was Hypostoma squalinum by Jardine in Schomburgk (1841),
with the type locality in the Branco, Negro, and Esequibo rivers; however the type was lost
and no records of it exist. Kner (1854) described Hypostomus horridus from the Rio
Guapore in Brazil, and designated several dried specimens as syntypes. After the description
of these species, there was a change at the generic identification of the species and
subsequent authors used Plecostomus Gronovius 1754.
Before the invalidation of Gronovius? works, 17 species within Isorineloricaria were
diagnosed within Plecostomus. Edward Drinker Cope was a prolific describer of fish, with
three described species within this group: P. biseriatus, P. scopularius, and P. virescens al
described by him from the upper Amazon River (Cope 1871, 1872, 1874). The syntypes of
P. virescens and the holotype of P. biseriatus are al juveniles and of poor quality, but the
holotype of P. scopularius is in excelent condition. Plecostomus vilarsi was described by
L?tken in 1874, and several syntypes were designated, yet the exact locality is unclear. It
was originaly noted as Caracas (Venezuela), yet that note was followed by a question mark,
and I disagree with that locality identification based on examination of specimens from the
Maracaibo basin and the lack of specimens of Isorineloricaria from the streams surrounding
Caracas. Armbruster (2005) found that Ancistrus mystacinus, which also has a stated
locality of ?Caracas?? (Kner, 1854: 276), was from the Lake Maracaibo basin, and it
appears as if this is also true for P. vilarsi. Steindachner (1878, 1880, 1881, 1908) described
P. tenuicauda, P. spinosisimus, P. annae, and P. unicolor, respectively. Fowler (1913,
1940a, 1940b, 1941, 1942, 1945) was the most prolific author of species descriptions within
the group, describing P. madeirae, P. phrixosoma, P. chaparae, P. iheringi, P. gomesi, and
4
P. winzi respectively. Fowler (1942) objectively invalidated P. iheringi after learning that P.
iheringii had already been used to describe another species of Plecostomus, and P. gomesi
was chosen to replace P. iheringi.
Aphanotorulus frankei was described by Isbr?cker and Nijsen (1982). Armbruster
and Page (1996) described A. ammophilus and expanded Aphanotorulus to include
Plecostomus chaparae, P. madeirae, P. micropunctatus (La Monte 1935), P. popoi (Pearson
1924), and P. unicolor. Armbruster?s (1998) review of Aphanotorulus left the genus with
just two valid species: A. ammophilus and A. unicolor; al the other members of
Aphanotorulus were found to be junior synonyms of A. unicolor.
Squaliforma (Isbr?cker and Michels; in Isbr?cker et al. 2001) was described with
litle supporting evidence given to recognize the group at the time, and the genus?
monophyly was not examined. Weber (in Reis et al. 2003) identified and placed other
species in Squaliforma, but without comment. He also removed Hypostomus watwata from
Squaliforma, hypothesizing that it belonged elsewhere in Hypostomus.
Phylogenetics: Species that conform to Isorineloricaria were first hypothosized to
be a monophyletic group in Armbruster and Page (1996). Genetic studies by Montoya-
Burgos et al. (2002) and Montoya-Burgos (2003) also suggest that these species form a
monophyletic group. Both studies concluded that the inclusion of the H. emarginatus group
in Hypostomus made Hypostomus polyphyletic, but gave no mention of elevating the group
to a separate genus.
Armbruster (2004, 2008) provided the most complete phylogeny for loricariids to
date, but focused on the Hypostominae. Armbruster?s analysis confirmed Armbruster and
Page?s (1996) findings, and he diagnosed Isorineloricaria (his H. emarginatus group) by an
5
elongated first hypobranchial, seven or more infraorbital plates, contact betwen the
metapterygoid and lateral ethmoid shifted anteriorly, an enlarged central papila in the
buccal cavity, and hypertrophied odontodes on the bodies of breeding males. He also
recognized that the unique coloration of these species makes them readily identifiable from
most other Hypostomus, and that future analyses might recognize the clade as a single genus
distinct from Hypostomus.
Other than studies on the species ascribed to Aphanotorulus, there has been no
detailed taxonomic work on Isorineloricaria, and no species described since 1945. In this
paper, the species of Isorineloricaria are redescribed, Plecostomus annae and Hypostoma
squalinum are placed in the synonymy of I. emarginata, Plecostomus biseriatus, P.
scopularis, and P. virescens are placed in the synonymy of I. horrida, Plecostomus winzi is
placed in the synonymy of I. tenuicauda, and one new species is described from the Apure
River basin of Venezuela.
6
Materials and Methods
Counts and measurements follow Boeseman (1968) and Armbruster and Page
(1996). Plate row terminology follows Schaefer (1997). Specimens were cleared and stained
following methods of Taylor and Van Dyke (1985). Institutional abbreviations follow the
American Society of Ichthyologist and Herpetologist Standard International Codes
(http:/ww.asih.org). Other abbreviations listed below include: D. = distance, Dp. = depth,
W.= width, L. = length.
Specimens were measured with digital calipers to the nearest 0.1 mm. Counts and
measurements of bilateraly symmetric features were taken on the left side when possible.
Measurements taken are labeled in Figures 2-4.
Morphometric data were analyzed using JMP (ver. 5.0.1.a, SAS Institute, 2002).
Measurements were examined through the use of bivariate plots to search for any diagnostic
characters. Diagnostic characters apply only to specimens greater than 100mm SL, unles
otherwise noted. Measurements were also examined multivariately using principal
component analysis (PCA). The first component of PCA was excluded because it represents
overal size diference. The remainder of the principal components were plotted against
standard length to show that they represent relative size diferences (shape). Specimens of
Isorineloricaria ammophila and I. unicolor were excluded from this analysis because they
7
were previously analyzed using the same data set (Armbruster 1998). Only specimens
greater than 100mm SL were included in the analysis.
8
Isorineloricaria Isbr?cker 1980
Type species: Plecostomus spinosisimus (Steindachner 1880)
Diagnosis: As a member of Hypostomini, (sensu (Armbruster, 2004)
Isorineloricaria can be separated from the Corymbophanini by having an adipose fin (vs.
adipose fin replaced by postdorsal ridge 13?17 azygous plates); from the Corymbophanini
and Rhinelepini by having the iris operculum (vs iris operculum absent); from the
Rhinelepini by lacking exposure of the coracoid strut (vs. coracoid strut exposed, supporting
odontodes), and by having the anal fin I,4 (vs. I,6); from the Pterygoplichthini by having the
stomach atached via the dorsal mesentery only (vs. connected to the lateral abdominal wals
by a connective tisue sheet) and by usualy having one plate betwen the suprapreopercle
and opercle, rarely two (vs. two to three); from the Ancistrini (except Spectracanthicus
murinus and some Pseudancistrus) and the Pterygoplichthini by having the cheek plates
evertible to about 30? to the head and generaly lacking hypertrophied odontodes on the
cheek plates with the only exception nuptial males in a few species (vs. cheek plates
evertible to 70? or more and hypertrophied odontodes usualy present); from
Spectracanthicus by having the dorsal and adipose fins separate (vs. connected by a
posterior extension of the dorsal fin), and from Pseudancistrus without evertible cheek
plates by lacking hypertrophied odontodes on the cheek and along the snout except in
nuptial males of a few species (vs. odontodes present in males and females along the snout
and on the cheek) and three plates betwen the head and dorsal fin (including the nuchal
plate, vs. four or more).
9
Within the Hypostomini, Isorineloricaria can be separated from Hypostomus by an
elongated caudle peduncle (vs. short caudle peduncle in Hypostomus), elongate
hypertrophied breeding odontodes on nuptial males (vs. absence of hypertrophied odontodes
in Hypostomus), central buccal papila enlarged or multiple buccal papilae (vs. smal or
absent buccal papilae in Hypostomus) and from most Hypostomus by their lighter
background coloration (vs. darker background coloration in Hypostomus).
Description: Member of the Loricariidae: Hypostominae: Hypostomini.
Dorsoventraly flatened and elongate fishes, covered in plates. Head depth moderate to
deep; suppraocipital crest from much higher than nape and posterior edge perpendicular to
head, to greatly reduced, only slightly higher than nape and posterior edge level with nape.
Nape flat to increasing in height posteriorly to dorsal fin. Dorsum sloped ventraly to
procurrent fin rays and then elevating quickly to caudal fin.
Highly forked caudal fin with lower caudal lobe longer than upper caudal lobe.
Pectoral-fin spines extend from just short of pelvic-fin insertion to just past pelvic-fin base.
Pelvic fin spine reaches anal-fin insertion. Adipose fin present and triangular. Dorsal-fin
spine not longer than first dorsal-fin ray; dorsal fin not reaching insertion of adipose fin
when adpresed (more than one plate separating them).
Lips flat with short maxilary barbel on marginal edge. Bucal papila present;
bucal papilae range from multiple smal papilae with central one enlarged to enlarged
single papila (Fig. 8). Teth numerous, bicuspid, with long stalks.
Sexual Dimorphism: In breeding males, hypertrophied odontodes present on
pectoral- and caudal-fin spines in increasing density and length distaly. Slightly lengthened
odontodes also found on edges of most plates and the adipose fin tip. Smal odontodes
10
found on dorsal-fin spine, and sometimes randomly along paired fin rays. In peak spawning
season, pectoral and pelvic spines of breeding males swollen. Hypertrophied odontodes may
cover entire dorsal and lateral surfaces in some species including cheek and edge of snout.
Coloration: Light tan to white background, with brown to black spotting. Color in
life similar to that in alcohol, yet some individuals show hints of orange and red in
background colors. Dorsal surfaces and fins with spots; ventral surfaces with or without
spots. Color paterns difer with ontogeny, and vary with species. In general, juveniles with
proportionaly larger spots than adults.
Etymology: Isbr?cker (1980) derived the name Isorineloricaria from the Greek
word isos ?like? and Rineloricaria, a genus of the Loricariinae, which also have elongate
caudal peduncles.
11
Isorineloricaria ammophila (Armbruster and Page 1996)
(Fig. 9)
Aphanotorulus ammophilus Armbruster & Page, 1996: 385, fig. 2 (middle). Type
locality: Venezuela, Estado Cojedes, R?o San Carlos, R. Portuguesa drainage at Ca?o
Hondo, 2 km west of Las Vegas on the road from Las Vegas to Campo Alegre ?
9?31'51"N, 68?39'39"W. Holotype: INHS 32035, 86.0 mm SL.
Diagnosis: Isorineloricaria ammophila is diagnosable from al other members of
Isorineloricaria, except I. unicolor, by its numerous buccal papilae. Isorineloricaria
ammophila is diagnosable from I. unicolor by the presence of ridges formed by the
compound pterotics on the head (vs. ridges absent in I. unicolor); a pectoral fin that, when
depresed, wil reach wel past the point of insertion of the last pelvic fin ray (vs. extending
maximaly to the insertion of the last pelvic fin ray in I. unicolor). Se diagnosis of I.
unicolor below for further diagnostic features for specimens greater than 75mm SL.
Description: Morphometric data given in Table 4. Head slightly compresed with
raised supraoccipital crest; crest ending abruptly with posterior edge perpendicular to head.
Sharp ridge present on compound pterotics. Large flap covering posterior opening of nare.
Interorbital surface flat. Nape increasing in height posteriorly to dorsal fin.
Dorsal-fin spine slightly longer than or equal in length to first dorsal-fin ray.
Pectoral-fin spine reaches past point of insertion on pelvic fin. Pelvic fin spine reaches
insertion of the anal fin. Adipose-fin membrane extending to end of fourth adipose base
plate (two plates separates adipose-fin membrane and first dorsal procurrent caudal-fin
spine).
12
Lateral line plates 28-30 (mode 29; n= 93); dorsal-fin base plates six to 10 (mode
seven; n= 93); folded dorsal plates 10-14 (mode 13; n= 90); plates betwen dorsal and
adipose fins seven to 10 (mode eight; n= 93); adipose- fin plates three to four (mode three;
n= 92); anal- fin base plates two to three (mode two; n= 93); plates from anal- fin insertion
to last plate on caudal peduncle 13-16 (mode= 14; n= 93); plates in folded pectoral fin five
to seven (mode six; n= 93); number of teth on dentary 9-20 (mode= 14; n= 92); number of
teth on premaxila 10-18 (mode= 14; n= 92).
Sexual Dimorphism: Breeding males with elongated odontodes on dorsal and
lateral surfaces of body posterior to insertion of dorsal fin, increasing in length and density
posteriorly. Odontodes also present on pectoral-fin spines and caudal-fin spines.
Color in alcohol: Light tan to white background. Ventral surface white. Dorsal and
lateral surfaces with dark, round spots. Spots smal to medium in size. Spots form
longitudinal rows in some specimens, more random in other specimens. Spots on caudal fin
create vertical bars when fin is compresed. On dorsal fin, two rows of spots lie betwen
each fin ray. Juveniles with four brown saddles, a brown midlateral stripe, and a mottled
head.
Range: (Fig. 20) R?o Orinoco drainage in Venezuela, mainly from the R?o Apure
system. Possibly occurs in headwater streams of the R?o Apure within Columbia.
13
Isorineloricaria n. sp. ?Apure? New Species
Ray and Armbruster
(Fig. 10?11)
Holotype: INHS 35685, 269.1mm SL. Venezuela: Rio Portuguesa, 3 km northeast of El
Barriero, Portuguesa. 09?03?08?N, 069?29?18?W. 1 January 1995. Collected by J.W.
Armbruster, P.A. Ceas, M.H. Sabaj, C.A. Laird, S.M. Phelps, M.L. Manrique, F.T.
Burbrink.
Paratypes: Venezuela: ANSP 134482, Rio Orituco, tributary of Rio Guarico, 15 km
SE of Calabozo on Cazorla Road; Orinoco drainage, Edo. Guarico, 25 November 1966,
col. by N.R.Foster, J.Ramsey; ANSP 134519, Rio Orituco, tributary of Rio Guarico, 15 km
SE of Calabozo on Cazorla Road, Edo. Guarico, 26 November 1966, col. by N.R.Forster;
ANSP 165834, Rio Orituco: ca. 15 km SE of Calabozo, Guarico, 2 November 1989, col. by
S.Schaefer, et al.; ANSP166888, Rio Orinoco Basin: Caicara; L.Bartolico, Bolivar, 12
January 1988, col. by M. Rodriguez; FMNH 105992, Rio Suripa ca. 0.5 hrs by boat above
confluence with Rio Caparo, Barinas, 07?40?00?N 070?28?00?W, 9 January 1991, col. by B.
Chernoff, A. Machado, R. Royero, F. Gil; FMNH 105993, Playa Los Chicos in the Rio
Suripa ca. 2.5 hrs. above Hato Mercedes, Barinas, 12 January 1991, col. by B. Chernoff, A.
Machado, R. Royero, F. Gil; INHS 34432; INHS 35685; MCNG 34719; UF 80345; UF
80390 (XX), Rio Apure in Apurito, near chalana site., Apure, 7?56?0?N 68?28?50?W, D.C.
Taphorn, C.R. Gilbert, L. Nico, 6 April 1984; USNM 348458, Rio Orituco where crossed by
road from Calabozo, Guarico, 8.867, -67.300, 27 January 1983, col. by A. Machado-Alison
et al.
14
Diagnosis: Isorineloricaria n. sp. ?Apure? can be diagnosed from I. ammophila and
I. unicolor by a single, large buccal papilae (vs. multiple buccal papilae present in I.
ammophila and I. unicolor); from I. spinosisima by having a larger caudal fin depth to head
length ratio (se diagnosis of I. spinosisima); from I. vilarsi by having a flatened
compound pterotic (vs. sharp ridges present in I. vilarsi); from I. emarginata by having a
larger orbit diameter to interorbital width ratio (40.6?63.7% vs. 32.4?40.5%), which
separates 96% of individuals; from I. horrida by having a supraoccipital crest with posterior
edge perpindicular to head (vs. I. horrida with posterior edge gently sloping into nape); and
from I. tenuicauda by having a larger caudal peduncle width to pectoral spine length ratio
(59.6? 65.2% vs. 31.5? 56.2%), which separates 95% of individuals.
Description: Morphometric data given in Table 1. Head deep with tall
supraoccipital crest; crest ending abruptly with posterior edge perpendicular to head.
Rounded ridge forming on outer edge of each nare, rising dorsaly over orbit, abrubtly
ending postorbitaly. Large flap covering posterior opening of nare. Interorbital surface flat.
Nape flat.
Dorsal-fin spine not longer than first dorsal-fin ray. Pectoral-fin spine reaches past
insertion of pelvic fin. Pelvic-fin spine just reaches insertion of anal fin. Adipose-fin
membrane extending to end of third adipose base plate (one plate separates adipose-fin
membrane and first dorsal procurrent caudal-fin spine).
Lateral line plates 27-30 (mode= 30; n= 23); dorsal-fin base plates seven to eight
(mode= eight; n= 23); folded dorsal plates 11-13 (mode= 13; n= 23); plates betwen dorsal
and adipose fins seven to 10 (mode= nine; n= 23); adipose fin plates two to four (mode=
three; n= 23); anal fin base plates two to three (mode= two; n= 23); plates from anal fin
15
insertion to last plate on caudal peduncle 16-19 (mode= 19; n= 23); plates in folded pectoral
fin five to eight (mode= six; n= 22); number of teth on dentary 20-35 (mode= 24; n= 23);
number of teth on premaxila 17-41 (mode= 24; n= 23).
Sexual Dimorphism: Breeding males with hypertrophied odontodes on pectoral fin
spine, which increase in density and length distaly along spine. Paired-fin spines swel
distaly. Hypertrophied odontodes on caudal fin with largest spines occurring on caudal-fin
spines and along the caudal-fin rays. Slightly hypertrophied odontodes present on distal end
of adipose-fin spine. Hypertrophied odontodes covering posteromedial edge of most plates
along body. Longest plate odontodes occur on mid-dorsal, median, and mid-ventral plate
rows. Slightly hypertrophied odontodes also present on opercle, edge of snout, and
cleithrum.
Color in alcohol: Body base color light brown or tan with large, dark, longitudinaly
oblong brown spots. Spots rarely circular on body. Spots cover entire body except abdomen;
faint spots occur across ventral aspect of pectoral girdle in some specimens. Spots on paired
fins combining to form bands, some separate spots distaly. Dorsal-fin spine with dark spots
anteriorly; interradial membrane of dorsal fin with two rows of spots. Caudal fin with spots
that appear to form bands on upper lobe, and randomly distributed spots on lower lobe;
lower lobe of caudal fin with dark brown background color in most specimens. Large spots
sometimes visible on lower lobe of caudal fin when dark background absent or faded.
Spot paterning les concentrated in juveniles (more background color showing).
Spotting patern on fins becomes denser as fish ages. In juveniles one row of spots on
interradial membranes of dorsal fin, bifurcating distaly in larger specimens, eventualy
becoming two rows in adults.
16
Ecology: The holotype was collected in the Rio Portuguesa on a sandy run with
moderate flow. The holotype is a nuptial male with breeding odontodes, suggesting that
January is within the time of spawning as was suggested for I. ammophila (Armbruster and
Page, 1996).
Range: (Fig. 21) This species is restricted to the Apure and middle Orinoco rivers
and their tributaries in Venezuela. Only one specimen was from the main stem Orinoco
River, just downstream of the mouth of the Apure.
Comments: The one specimen of Isorineloricaria n. sp. ?Apure? collected in the
Orinoco River was also collected with a specimen of I. emarginata. This is the only known
instance of the two being collected together. The waters where the two rivers connect may
act as an extension of available habitat for each species, because the two are not known to
occur downstream of the connection in either river. Isorineloricaria n. sp. ?Apure? appears
to be restricted to white waters and I. emarginata to clear and blackwater rivers.
17
Isorineloricaria emarginata (Valenciennes 1840)
(Fig. 12)
Hypostomus emarginatus Valenciennes, in Cuvier & Valenciennes, 1840b: 500 (369 in
Strasbourg deluxe edition). Type locality: Probablement or Xginaire du Br?sil.
Holotype: MNHN a-9447 (dry).
Plecostomus annae Steindachner, 1881c: 112, pl. 3 (figs. 2?2a). Type locality: Par? [=
Belem, Brazil]. Holotype: NMW 44073. Listed as Chaetostomus annae in figure
caption (p. 146).
Hypostoma squalinum Jardine, in Schomburgk, 1841: 142, pl. 2. Type locality: Rios
Branco, Negro, and Esequibo. No types known.
Diagnosis: Isorineloricaria emarginata is diagnosable from I. ammophila and I.
unicolor by the presence of a large buccal papilae (vs. multiple buccal papilae present in I.
ammophila and I. unicolor); from I. spinosisima, and I. tennuicauda, and I.vilarsi by
having flat compound pterotics (vs. rounded ridge present in I. spinosisima and I.
tennuicauda and a sharp ridge present in I. vilarsi compound pterotics); from I. vilarsi by
lack of sharp ridge on compound pterotics (vs. sharp ridge present); from Isorineloricaria n.
sp. ?Apure? by having a smaler orbit diameter to interorbital width ratio (32.4?40.5% vs.
40.6?63.7%), which separates 96% of individuals; also from Isorineloricaria n. sp. ?Apure?
by having smaler, more circular spots on the head (vs. larger, oval spots in Isorineloricaria
n. sp. ?Apure?); from I. horrida by having a larger snout-nares distance to interorbit width
ratio (98.0?175.4% vs. 70.5? 97.8%; Fig. 6); also from I. horrida by having circular spots
18
on the dorsal and paired fins which remain unfused across the length of the fin (vs. spots
that fuse into bands across the dorsal and paired fins, mostly in adults).
Description: Morphometrics given in Table 1. Head moderately compresed.
Supraoccipital crest not tal, with posterior edge sloping gently into nape. Interorbital
surface flat. Nape increasing in depth posteriorly to dorsal fin. Pectoral fin reaches past
point of insertion of pelvic fin. Depresed pelvic spine reaches point of insertion of the anal
fin. Adipose fin triangular.
Lateral line plates 26-31 (mode= 29; n= 118); dorsal-fin base plates six to nine
(mode= seven; n= 118); folded dorsal plates nine to 14 (mode= 12; n= 118); plates betwen
dorsal and adipose fin seven to 12 (mode= nine; n= 118); adipose fin plates two to three
(mode= three; n= 117); anal-fin base plates two to three (mode= two; n= 118); plates from
anal fin insertion to last plate on caudal peduncle 14-19 (mode= 18; n =118); plates in
folded pectoral fin five to eight (mode= six; n =116); number of teth on dentary 10-45
(mode= 26; n =118); number of teth on premaxila 14-45 (mode= 29; n =118).
Sexual Dimorphism: Breeding males with hypertrophied odontodes on pectoral-fin
spine, which increase in density and length distaly along spine. Paired-fin spines swel and
become larger distaly. Odontodes also on caudal fin, with largest odontodes on spines and
rays. Odontodes also covering posteromedial edge of most plates on lateral surface of body;
most relatively short. Longest plate odontodes occur on mid-dorsal, median, and mid-ventral
plate rows. Slightly lengthened odontodes present on cheek.
Color: Light tan to white background. Spotting patern highly variable across range.
Spots smal to medium in size; can be very dense (les background color showing) to very
sparse (more background color showing) across entire body. Ventral surface with some
19
spots across pectoral girdle or no spots. Spots on fin rays similar to those on body. Spots
irregularly placed on paired-fin rays. Dorsal-fin membrane with two distinct rows of spots
betwen each fin ray. Lower caudal fin lobe dark in color, almost black in some specimens.
Range: (Fig. 22) A wide-ranging species, I. emarginata?s range includes the upper
Orinoco River (except the Rio Apure); the Esequibo River and it tributaries; the lower
Amazon River including the Rio Negro, the Rio Tapajos, and the Rio Xingu.
20
Isorineloricaria gomesi (Fowler 1941)
(Fig. 13)
Plecostomus iheringi Fowler, 1941a: 150, figs. 50?52. Type locality: Cear? [Brazil].
Holotype: ANSP 69409. Preoccupied by Plecostomus iheringii Regan, 1908;
replaced by Plecostomus gomesi Fowler, 1942.
Plecostomus gomesi Fowler, 1942: [1]. Type locality: Cear? [Brazil]. Holotype: ANSP
69409. Replacement name for Plecostomus iheringi Fowler, 1941; preoccupied by
Plecostomus iheringii Regan, 1908.
Diagnosis: Known only from holotype. Isorineloricaria gomesi is diagnosed from I.
ammophila and I. unicolor by a single, large buccal papilae (vs. multiple buccal papilae);
from al other Isorineloricaria only by its distribution (thought to be found only in the
Jaguaribe River, Cear? state, Brazil).
Description: Morphometrics given in Table 5. Head moderately compresed.
Suppraoccipital crest not tal, with posterior edge sloping gently into nape. Interorbital
surface flat. Nape slightly increasing in depth posteriorly. Pectoral fin reaches past point of
insertion of pelvic fin. Depresed pelvic spine reaches point of insertion of the anal fin.
Lateral line plates 29; dorsal-fin base plates eight; folded dorsal plates 12; plates
betwen dorsal and adipose fin seven; adipose fin plates two; anal-fin base plates two; plates
from anal fin insertion to last plate on caudal peduncle 16; plates in folded pectoral fin five;
number of teth on dentary 24; number of teth on premaxila 25.
Color in alcohol: Dark tan background. Spots smal to medium in size; moderately
dense (les background color showing) on head. Few if any spots visible along dorsal and
21
lateral sides of body. Ventral surface with no spots. Spots on fin rays similar to those on
body. No paterns on paired-fin rays. Dorsal-fin membrane with two distinct rows of spots
betwen each fin ray. Caudal fin with spots in vertical bands. Lower caudal fin lobe dark in
color.
Range: (Fig. 21) Isorineloricaria gomesi is only known from its type locality. No
other specimens are known.
22
Isorineloricaria horrida (Kner 1854)
(Fig. 14)
Hypostomus horridus Kner, 1854: 259, pl. 1 (fig. 1). Type locality: Forte do Principe am
Rio Guapor?, Brazil. Syntypes (3): NMW 16325 (1), NMW 86604 (1). Originaly
proposed as Hyp. horridus.
Plecostomus biseriatus Cope, 1872a: 285. Type locality: the Amazon, betwen the mouth
of the Rio Negro and the Peruvian Amazon or Ucayale River. Holotype: ANSP
8279.
Plecostomus scopularius Cope, 1871a: 55. Type locality: the Amazon above the mouth of
the Rio Negro. Lectotype: ANSP 8081, designated by Fowler (1915: 233); ilustrated
in Cope (1872a: pl. 16, no. 1).
Plecostomus virescens Cope, 1874b: 137. Type locality: not explicitly given [Upper
Amazon]. Syntypes: ANSP 21280 (4).
Diagnosis: Isorineloricaria horrida can be diagnosed from I. ammophila and I.
unicolor by a single, large buccal papilae (vs. multiple buccal papilae); from I.
spinosissima and I. tenuicauda by having flat compound pterotics (vs. rounded ridges on the
compound pterotics in I. spinosisima and I. tenuicauda and sharp ridge present in I.
vilarsi); from I. emarginata by having a smaler snout-nares distance to interorbit width
ratio (70.5? 97.8% vs. 98.0? 175.4%), which separates 92% of individuals (Fig.6); from I.
spinosisima by having a larger caudal fin depth to head length ratio (se diagnosis of I.
spinosisima); from I. phrixosoma by having fewer elongate hypertrophied covering the
dorsal and ventral surfaces of body except the head (vs. many hypertrophied odontodes
present- se I. phrixosoma description); from Isorineloricaria n. sp. ?Apure? by having a
23
supraoccipital crest with posterior edge gently sloping into nape (vs. Isorineloricaria n. sp.
?Apure? with posterior edge perpindicular to head).
Description: Morphometric data given in Table 2. Head moderately deep with tal
supraoccipital crest; supraocipital crest taler than nape and posterior edge of crest gently
sloping into nape. Nape flat.
Pectoral-fin spine reaches posterior to insertion of pelvic fin. Pelvic-fin spine reaches
insertion of anal-fin spine. Two plates separate adipose-fin membrane and first dorsal
procurrent caudal fin spine.
Lateral line plates 27-30 (mode 28; n= 73); dorsal-fin base plates six to eight (mode
seven; n= 73); folded dorsal plates 10-14 (mode 12; n= 72); plates betwen dorsal and
adipose fin six to 11 (mode nine; n= 73); adipose fin plates one to four (mode three; n= 73);
anal fin base plates one to three (mode two; n= 73); plates from anal fin insertion to last
plate on caudal peduncle 13-19 (mode =17; n =73); plates in folded pectoral fin four to eight
(mode six; n =72); number of teth on dentary 10-42 (mode =27; n =73); number of teth on
premaxila nine to 37 (mode =22; n =73).
Sexual dimorphism: Breeding males with short hypertrophied odontodes on ventral
surfaces of body except the head. Odontodes on body short; only on posterior edges of
plates. Odontodes present on pectoral- and caudal-fin spines; odontodes increase in density
and length distaly on each fin spine. Hypertrophied odontodes absent from pelvic, dorsal,
and adipose fin spines.
Color in alcohol: Light tan background color with brown spots. Smal spots
covering head, increasing in size and becoming more elongate posteriorly along the body. In
adults, spots begin to fuse together on head to create lines with reticulated paterns; largest
24
specimens with mostly reticulated lines present, few spots remaining. Some specimens with
smal spots on ventral side of body along pectoral girdle. Paired fins with elongate spots,
usualy forming bands on fins. Dorsal fins in adults with elongate spots forming bands.
Smal, random spotting patern apparent on adipose fin. Lower half of caudal fin rays darker
in color than base color, dark coloration not extending to lower caudal spine.
Range: (Fig. 23) Isorineloricaria horrida is found in the upper Amazon River,
including the mainstem, Rio Napo, Rio Mara?on, Rio Ucayali, Rio Juru?, Rio Purus, and
Rio Madiera.
25
Isorineloricaria phrixosoma (Fowler 1940)
(Fig. 15A?C)
Plecostomus phrixosoma Fowler, 1940a: 233, figs. 21?23. Type locality: Ucayali River
basin, Contamana, Peru. Holotype: ANSP 68650.
Diagnosis: Isorineloricaria phixosoma is diagnosable from I. ammophila and I.
unicolor by a single, large buccal papilae (vs. multiple buccal papilae in I. ammophila and
I. unicolor); from al other Isorineloricaria by the presence of hypertrophied odontodes
covering al lateral and ventral surfaces except the head in breeding males (vs. covering al
dorsal and lateral surfaces including the head in I. spinosisima and vs. covering portions of
dorsal and lateral surfaces in al other Isorineloricaria). This species is known only from its
holotype, which is a breeding male.
Description: Morphometric data given in Table 5. Head moderately deep.
Interorbital surface flat; nape of unknown shape due to damage.
Pectoral-fin spine reaches past point of insertion on the pelvic fin. Pelvic-fin spine
reaches past the point of insertion of the anal fin. Caudal fin highly forked with lower lobe
longer than upper lobe.
Lateral line plates 28; dorsal fin base plates seven; folded dorsal plates 12; plates
betwen dorsal and adipose fin seven; adipose fin plates two; anal fin base plates two; plates
from anal fin insertion to last plate on caudal peduncle 15; plates in folded pectoral fin six;
number of teth on dentary 21; number of teth on premaxila 15.
26
Sexual Dimorphism: Although smal, holotype breeding male. Entire dorsal and
lateral surfaces of body covered with hypertrophied odontodes. Dorsal surface of head
without odontodes.
Color in alcohol: Body background color light, almost white. Spots on head smal
and circular; densely packed. Dorsal-fin membranes with two rows of spots. Few spots
visible on body due to hypertrophied odontodes.
Range: (Fig. 21) Rio Ucayali, near Contamana, Peru. Known only from type
locality.
Comments: I hypothesize that his species is actualy a hybrid. This specimen was
collected in an area where both I. horrida and I. unicolor are sympatric. It should be noted
that the specimen does not share the multiple buccal papilae or the unicuspid teth of
nuptial I. unicolor, yet it is the smalest breeding male (with hypertrophied odontodes)
collected of any species of Isorineloricaria, other than I. ammophila and I. unicolor. Given
these combination of characters and the high sampling efort in the drainages around the
type localityresuting in no more specimens of the species, hybridation is a very ; however,
given the poor condition of the specimen and lack of other speimens
27
Isorineloricaria spinosisima (Steindachner 1880)
(Fig. 16)
Plecostomus spinosisimus Steindachner, 1880b: 98, pl. 5 (figs. 1, 1a). Type locality:
Guayaquil [Ecuador]. Holotype: NMW 55027.
Plecostomus festae Boulenger, 1898c: 11. Type locality: Rio Vinces and Rio Peripa,
Equateur. Syntypes: BMNH 1898.11.4.32 (1), ZMUT 1518 (1).
Diagnosis: Isorineloricaria spinosisima can be diagnosed: from I. ammophila and
I. unicolor by the presence of a single, large buccal papilae (vs. multiple buccal papilae
present in I. ammophila and I. unicolor); from al other Isorineloricaria by having a smaler
caudal fin depth to head length ratio (16.5?19.1% vs. 20.6?30.1%).
Description: Morphometric data given in Table 2. Head moderately deep; tall
supraoccipital crest with posterior edge level with nape. Interorbital surface flat. Nape with
increasing height from posterior edge of the supraoccipital to the insertion of the dorsal-fin
spine. Extremely elongate caudal peduncle in adults; caudal peduncle circular in cross-
section.
Pectoral-fin spine does not reach insertion of pelvic fin. Pelvic-fin spine does not
reach point of anal fin insertion.
Lateral line plates 31-33 (mode 32; n= 11); dorsal fin base plates seven to eight
(mode seven; n= 11); folded dorsal plates 10-14 (mode 13; n= 11); plates betwen dorsal
and adipose fin nine to 11 (mode 10; n= 11); adipose fin plates three to four (mode four; n=
11); anal fin base plates two to three (mode two; n= 11); plates from anal fin insertion to last
plate on caudal peduncle 19-21 (mode =20; n =11); plates in folded pectoral fin four to
28
seven (mode four; n =11); number of teth on dentary 19-31 (mode =19; n =11); number of
teth on premaxila 17-34 (mode =29; n =11).
Sexual dimorphism: Breeding males with hypertrophied odontodes on al surfaces
of body except ventral surface of head and abdomen. Odontodes present on pectoral, dorsal,
adipose, and caudal- fin spines; odontodes increase in density and length distaly on each fin
spine.
Color in alcohol: Body background white to light tan. Spots numerous on dorsal
and lateral surfaces. Spots dark brown; not uniform in shape and moderate to very dense,
especialy on head. Random spotting on paired fins. Dorsal fin with two rows of spots
betwen each ray. Spots dificult to view in breeding males due to distortion caused by
presence of breeding odontodes. Ventral surfaces without spots.
Juveniles with much lighter base color and very large dark spots. Spots randomly
distributed on dorsal and lateral surfaces and al fins.
Range: (Fig. 21) Endemic to the Guayas River basin, Ecuador.
Comments: Large ontogenetic shape change betwen juveniles and adults. Isbr?cker
(1980) suggested Plecostomus festae be recognized as a separate species from I.
spinosisima due to their wide variation in shape and size; however, Weber (in Reis et. al
2003) recognized P. festae as a junior synonym of I. spinosisima. The ontogenetic shifts in
shape most likely explain the wide variation in counts and measurements.
29
Isorineloricaria tenuicauda (Steindachner 1878)
(Fig. 17)
Plecostomus tenuicauda Steindachner, 1878a: 90. Type locality: Magdalenen-Stromes
[Colombia]. Syntypes: MSNG 8856 (1), NMW 42596 (1), NMW 44263 (1), NMW
44264 (1), NMW 44265 (1), NMW 44266 (3), NMW 44268 (1), NMW 44294 (1),
ZMUC P 30172 (1). One syntype ilustrated in Steindachner (1879d: pl. 6).
Plecostomus winzi Fowler, 1945b: 9, figs. 4?7. Type locality: Honda, Colombia.
Holotype: ANSP 71623. Distribution: Magdalena River basin, Colombia, known
only from holotype (Weber, 2003).
Diagnosis: Isorineloricaria tenuicauda can be diagnosed from I. ammophila and I.
unicolor by a single, large buccal papilae (vs. multiple buccal papilae present in I.
ammophila and I. unicolor); from I. vilarsi, I. emarginata, and I. horrida by a rounded
ridge present on the compound pterotics (vs. sharp ridge present on I. vilarsi and ridge
absent on I. emarginata and I. horrida); from I. spinosissima by having a larger caudal fin
depth to head length ratio (se diagnosis of I. spinosisima); from Isorineloricaria n. sp.
?Apure? by having a smaler caudal peduncle width to pectoral spine lenth ratio (31.5?56.2%
vs. 59.6?65.2%), which separates 95% of individuals.
Description: Morphometric data given in Table 3. Head moderately deep with tal
supraoccipital crest; crest often ending sharply. Ridges formed on compound pterotics
rounded in most specimens (lack a sharp ridge). Nape slightly increasing in height
posteriorly.
30
Pectoral-fin spine reaches posterior to insertion of pelvic fin. Pelvic-fin spine reaches
insertion of anal-fin spine. Adipose-fin spine triangular, adipose-fin membrane extending to
third adipose fin plate (two plates separate adipose-fin membrane and first dorsal procurrent
caudal fin spine).
Lateral line plates 28-29 (mode 28; n = 12); dorsal fin base plates seven to nine
(mode eight; n = 12); folded dorsal plates 13-15 (mode 13; n = 12); plates betwen dorsal
and adipose fins six to nine (mode eight; n = 12); adipose fin plates three to four (mode
three; n =12); anal-fin base plates two to three (mode two; n =12); plates from anal fin
insertion to last plate on caudal peduncle 15-17 (mode =17; n =12); plates in folded pectoral
fin five to nine (mode seven; n =12); number of teth on dentary 20-35 (mode =29; n =10);
number of teth on premaxila 20-35 (mode =30; n =12).
Sexual Dimorphism: Breeding males with hypertrophied odontodes on pectoral-,
adipose-, and caudal-fin spines, which increase in length and density distaly. Smal
hypertrophied odontodes on the dorsal-fin spine. Hypertrophied odontodes also on the
pectoral- and caudal-fin rays. Paired-fin spines swollen. Hypertrophied odontodes covering
posteromedial edge of most plates along body, cheek plates, opercle, along snout, and
cleithrum.
Color in alcohol: Background light brown or tan. Covered in smal brown spots
over entire body. Some specimens lack spots on abdomen. Spots smal and uniform in size
al over body, except abdomen and paired-fin rays. Spots on abdomen vary from smal
single spots to large fused spots with open centers (circles and semicircles). Some elongate
(fused) spots on paired-fin rays. Two rows of spots betwen fin rays on paired fins. One row
of spots betwen rays on caudal fin. Dorsal-fin membranes with randomly placed spots.
31
Juveniles without abdominal spots. Smalest spots on head, with increasing size
posteriorly. Spots form bands in paired fins, dorsal fin and caudal fin.
Range: (Fig. 21) Isorineloricaria tenuicauda is restricted to the R?o Magdalena
basin, Colombia.
32
Isorineloricaria unicolor (Steindachner 1908)
(Fig. 18)
Plecostomus unicolor Steindachner, 1908f: 164. Type locality: Rio Pur?s. Lectotype:
NMW 44271: 2, designated by Armbruster (1998b: 254).
Plecostomus madeir? Fowler, 1913: 571, fig. 23. Type locality: Madeira River, about
200 miles east of W. long. 63?54'W, Brazil. Holotype: ANSP 39312.
Plecostomus popoi Pearson, 1924: 20, pl. 3 (fig. 2). Type locality: Popoi River, Upper
R?o Beni, Bolivia. Holotype: CAS 77346.
Plecostomus micropunctatus La Monte, 1935: 1, fig. 1. Type locality: Rio Purus: [...] in
the vicinity of the mouth of Rio Macauhan, a tributary of Rio Iaco which, in turn, is
a tributary of Rio Purus (70?15'W, 7?30'S). Holotype: AMNH 12598.
Plecostomus chaparae Fowler, 1940c: 81, figs. 38?40. Type locality: Boca Chapare, R?o
Chimore, Cochabamba, Bolivia. Holotype: ANSP 69067.
Aphanotorulus frankei Isbr?cker & Nijsen, 1983a: 108, figs. 1?2. Type locality: [...] du
P?rou, Dept. Ucayali, Prov. Coronel Portilo, syst?me du Rio Aguaytia. Rio
Neshua (environ 08?36'S, 74?50'W), 60 km S.O. de Pucalpa, le long de la route de
Tingo Maria. Holotype: ZMA 116.640.
Diagnosis: Isorineloricaria unicolor is diagnosable from al other members of
Isorineloricaria, except I. ammophila, by its numerous buccal papilae (vs. single, large
papila). Isorineloricaria unicolor is diagnosable from I. ammophila by the absence of a
ridge on the compound pterotic (vs. ridge present in I. ammophila). The urohyal is also
uniquely modified in I. unicolor. The urohyal in I. unicolor has arms, which are thin and
33
elongate, that overlap with the anterohyal (vs. short lateral arms of the urohyal that do not
overlap the anterohyal in most other Loricariids) (Armbruster 1998). In specimens larger
than 75mm SL, I. unicolor has a larger orbit diameter to snout length ratio (28.0?42.2% vs.
18.5?27.9%), a larger caudal depth to pectoral spine length ratio (25.6?35.1% vs. 19.8?
25.5%), and a smaler pectoral spine length to thorax length ratio (99.3?116.9% vs. 117.0?
136.3%) than I. ammophila (Armbruster 1998).
Description: Morphometric data given in Table 4. Head slightly compresed with
raised supraoccipital crest; crest ending abruptly with posterior edge perpendicular to head.
Large flap covering posterior opening of nare. Interorbital surface flat. Nape increasing in
height posteriorly.
Dorsal-fin spine slightly shorter than or equal in length to first dorsal-fin ray.
Pectoral-fin spine even with point of insertion on pelvic fin. Pelvic fin spine comes even to
insertion of the anal fin. Adipose-fin membrane extending to end of fourth adipose base
plate.
Lateral line plates 28-32 (mode 29; n = 307); dorsal fin base plates six to nine (mode
seven; n = 306); folded dorsal plates 10-13 (mode 12; n = 300); plates betwen dorsal and
adipose fins six to 10 (mode eight; n = 305); adipose fin plates two to four (mode three; n
=305); anal-fin base plates two to three (mode three; n =307); plates from anal fin insertion
to last plate on caudal peduncle 13-16 (mode =14; n =307); plates in folded pectoral fin four
to seven (mode five; n =302); number of teth on dentary four to 18 (mode =12; n =302);
number of teth on premaxila four to 17 (mode =12; n =304).
34
Sexual dimorphism: Breeding males have elongate, unicuspid teth. Hypertrophied
odontodes also present on the posterior dorsal and lateral plates. Odontodes also present on
the adipose- fin spine and upper caudal- fin spine.
Color in alcohol: Light tan to white background. Ventral surface white. Dorsal and
lateral surfaces with dark, round spots. Spots smal to medium in size. Spots form
longitudinal rows in some specimens, more random in other specimens. Spots on caudal fin
create vertical bars when fin is compresed. Spots on dorsal fin lie anterior to each dorsal fin
ray.
Range: (Fig. 20) A wide-ranging species, with populations known from upper
Amazon tributaries of Bolivia, Brazil, Colombia, Ecuador, and Peru.
35
Isorineloricaria vilarsi (L?tken 1874)
(Fig. 19)
Plecostomus vilarsi L?tken, 1874a: 211. Type locality: Caracas. Syntypes: ZMUC P
30149 (1), ZMUC P 30150 (1).
Diagnosis: Isorineloricaria vilarsi can be diagnosed from I. ammophila and I.
unicolor by a single, large buccal papilae (vs. multiple buccal papilae present in I.
ammophila and I. unicolor); from al other members of Isorineloricaria by having distinct
raised ridges on the compound pterotics (vs. rounded ridges on I. spinosisima and I.
tenuicauda and ridges absent in al other Isorineloricaria).
Description: Morphometric data given in Table 3. Head moderately deep with
prominent supraoccipital crest; crest often ending abruptly, with posterior edge
perpendicular to head. Ridges formed on compound pterotics; compound pterotic ridges
align with keel of mid-dorsal plate row to form continuous series. Nape flat.
Caudal fin highly forked with lower lobe longer than upper lobe. Pectoral-fin spine
reaches past point of insertion on the pelvic fin. Pelvic-fin spine comes even to the insertion
of the anal fin. Adipose fin spine pointed; adipose-fin membrane extending to end of third
adipose base plate (two plates separate adipose-fin membrane and first dorsal procurrent
caudal-fin spine).
Lateral line plates 28 (mode 28; n= 15); dorsal-fin base plates seven to nine (mode
eight; n= 15); folded dorsal plates 12-13 (mode 12; n= 15); plates betwen dorsal and
adipose fins seven to nine (mode eight; n= 15); adipose fin plates two to four (mode three;
n= 15); anal-fin base plates two (mode two; n= 15); plates from anal fin insertion to last
36
plate on caudal peduncle 16-18 (mode =17; n= 15); plates in folded pectoral fin five to
seven (mode six; n =151); number of teth on dentary 24-36 (mode =36; n= 15); number of
teth on premaxila 20-38 (mode =26; n= 15).
Sexual Dimorphism: Breeding males with hypertrophied odontodes on pectoral fin
spines, which increase in length and density distaly. Adipose-fin spine and caudal-fin
spines also covered with hypertrophied odontodes. Caudal-fin rays also with odontodes in
the same manner, though not as large as on caudal-fin spines. Hypoertrophied odontodes
also covering posteromedial edge of most plates along body. Longest plate odontodes occur
on mid-dorsal, median, and mid-ventral plate rows. Hypertrophied odontodes also present
on opercle, along snout, cleithrum, posterior edges of head, and dorsal-fin spine.
Color in alcohol: Body base color light brown or tan. Base color darkens in largest
specimens (breeding males). Spots oblong (not perfectly circular) on head and body.
Greatest density occurs on head, with spots increasing in size posteriorly. Spots on head
centered on anterior end of supraoccipital crest and radiate outward. Abdominal spots
observed in some specimens and range from smal spots with random distributions to large
spots in columns. Paired fin spines with bands, with paired fins having random spots that are
often fused together. Dorsal-fin spine with dark spots anteriorly; interradial membrane of
dorsal fin with two rows of spots betwen each fin ray. Caudal fin with random spotting.
Lower caudal fin lobe with dark coloration in large adults, with spots apparent.
Juveniles have no spots on abdomen. Spots appear to form bands on paired fins and
caudal fin when the fins are depresed in juveniles.
Ecology: Unknown, however habitat degradation within the Maricaibo basin is a
threat to this species.
37
Distribution: (Fig. 21) Isorineloricaria vilarsi is restricted to the Maracaibo basin
in northwestern Venezuela and extreme eastern Colombia.
Comments: There are two color morphs in the Maracaibo basin, one with smal
spots on the abdomen, and the other with large spots.
38
Results and Discussion
Hypostomus tenuis, which was originaly included in the H. emarginatus group, has
been removed from Isorineloricaria after examination of the type specimens. Its position
elsewhere in Hypostomus needs to be evaluated. Weber?s (Reis et al. 2003) removal of H.
watwata was in agreement with the phylogeny of Montoyo-Burgos (2003), where it was
found to be nested within Hypostomus and not Isorineloricaria. These conclusions suggest it
not be included in this study.
The PCA (Fig. 5) placed the species into three partialy overlapping distributions.
Isorineloricaria spinosisima was separate from al other species in the analysis, difering
mainly along PC2, which was strongly efected by measurements asociated with their long,
narrow caudal peduncles. The remainder of the species are in two overlapping groups
separating largely along PC3: an Amazon/Esequibo/Orinoco group of I. emarginata + I.
gomesi + I. horridus + I. phrixosoma and a trans-Andean/Orinoco group of Isorineloricaria
n. sp. ?Apure? + I. tenuicauda + I. vilarsi. PC3 also separated I. spinosisima from the
Amazon/ Esequibo/ Orinoco group. Within each group, there was a lot of overlap.
Isorineloricaria n. sp. ?Apure? has the smalest range on the graph, and was nested within
the distribution of I. vilarsi, with which I asume it to share a sister relationship.
Biogeography: A discussion of biogeography within this group is limited without a
current phylogenetic hypothesis; however, there are paterns that occur amongst the
39
distributions of the members of Isorineloricaria that mirror hypothesized geological events
that occurred within the last 70my across the South American continent. The rise of the
Andes in present day Ecuador led to a vicariant event that isolated the Guayas drainage from
the rest of the western basins on the continent, and the ancestors of I. spinosisimus. This
was the site of the Mara?on Portal, which is thought to have been a connection to the Pacific
Ocean for the Late Cretaceous drainages on the South American continent (Lundberg,
1998). Recent evidence does not suggest that it was a link to the Pacific Ocean, suggesting
that the present fauna may have been the result of stream capture during the rise of the
Andes.
During the middle to late Miocene, the vicariant events that divided the Magdalena
and Maracaibo basins from the Amazonas and Orinoco rivers were very important in the
evolution of Isorineloricaria. The further rise of the Andes in Colombia isolated the
Magdalena, which began ~11mya. The isolation of the Maracaibo basin began ~8mya with
the rise of the M?rida Andes, Sierra de Perij?, and the Eastern Cordilera (Lundberg, 1998).
This separated the Maracaibo basin from the Apure River, and the rest of the Orinoco
system. These vicariant events led to the isolation of populations of I. tenuicauda in the
Magdalena, I. vilarsi in the Maracaibo, and Isorineloricaria n. sp. ?Apure? in the Apure.
This patern of distribution suggests that I. spinosisima, I. tenuicauda, I. vilarsi, and
Isorineloricaria n. sp. ?Apure? would form a monophyletic group, and the patern of
isolation would suggest the following relationships: I. spinosisima + (I. tenuicauda + (I.
vilarsi, and Isorineloricaria n. sp. ?Apure?)). These four species do separate from the
Amazon/Esequibo/Orinoco group in the PCA providing some support for the group as
monophyletic.
40
The Amazon/ Esequibo/ Orinoco group may also form a clade together with
Isorineloricaria ammophila and I. unicolor. This group may have had an origin in the
Guiana and/or Brazilian Shields. Isorineloricaria emarginatus is found in both the Brazilian
and Guiana Shields, and this is likely the main area of South America that had appropriate
habitat for Isorineloricaria prior to the uplift of the Andes. The rise of the Andes may have
alowed the group to invade the piedmont, where the smaler species (I. ammophila, I.
phrixosoma, and I. unicolor) evolved. It should also be noted that the approximate dividing
point of the ranges of I. horrida and I. emarginata is the Purus arch, though no conclusions
of its importance can be made here.
The distribution of Isorineloricaria ammophila and I. unicolor are unique and
represent more recent vicariant events (Armbruster and Page 1996). These sister taxa have a
distribution which is suggestive of a distribution following the drainage paterns of the Late
Miocene (10.8?8mya) which was characterized by a large river flowing along the base of
the Andes and draining into the Caribbean at the present day mouth of Lake Maracaibo.
The dichotomy betwen the taxonomies of Armbruster (2004) and Isbr?cker (2001) are
glaring in terms of the number of genera recognized within the Hypostomini. Although the
most recent published support is for recognizing a single genus as in Armbruster (2004,
2008), this has largely not been acepted as is obvious from Ferraris? (2007) recognition of
Aphanotorulus, Isorinelorica, and Squaliforma, which are clearly monophyletic, monotypic,
and paraphyletic genera respectively. With 130 species, the taxonomy of the Hypostomini is
complex. It is clear that Isorineloricaria as recognized herein is a wel-diagnosed,
monophyletic clade. What is unknown is whether recognizing it as such wil make
Hypostomus paraphyletic, and I leave this question to future researchers.
41
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46
Material Examined
Isorineloricaria emarginata: Brazil: ANSP 187270 (3); MCZ 7805 (1); MCZ 7807 (2);
MCZ 7824 (1); MCZ 7840 (2); MCZ 7860 (1); MCZ 7992 (1); MNRJ 12710 (1), rio Pasa
Tr?s, afluente esquerdo rio Maranh?o, alto Tocantins, Urua?u, Goias, 14?30?S, 49?9?W,
G.W. Nunan, D.F. Moraes Jr., 26 October 1996; MNRJ 12781 (1), Rio Bagagem, ?
montante da foz do c?rrego Barriguda, afluente direito Rio Maranh?o, alto Tocantins,
Niquel?ndia, Goi?s, 14?5?S 48?14?W, col. by G.W. Nunan & D.F. Moraes Jr., 15 October
1985; MNRJ 12932 (1), Rio Tocantins, em Porto do Garimpo, mun. Mina?u/Cavalcante,
Mina?u, Goi?s, 13?34?5?S 48?6?4?W, col. by D.F. Moraes Jr., 13 January 1988; MNRJ
12944 (1), Afluente do c?rrego Lageado (afluente margem esquerda Rio Tocantins) na
estrada para Porto Rubi?o, Mina?u, Goi?s, 13?38?85?S 48?19?12?W, col. by D.F. Moraes Jr.,
16 January 1988; MNRJ 18360 (1), po?as formadas por riacho da margem esquerda do Rio
Tocantins, a montante de Ponte Rub?o durante enchimento, Colinas do Sul, Goi?s, col. by
D.F. Moraes, D.A. Habolth, O.T. Oyakawa et al., 28 October 1996; MNRJ 19338 (1), Rio
Tocantins, pr?ximo da cidade de Tucuru?, Tucuru?, Par?, col. by L.C. Alvarenga; MNRJ
29536 (1); MNRJ 31177 thru 31196= Same locality data; MZUSP 24064 (1), Rio Tocantins,
entre Mocajuba e Bai?o, Bai?o, Par?, 2?40?S 49?42?W, col. by Expedi??o Permanente ?
Amaz?nia, 9 September 1970; MZUSP 24086 (1), Lago ?s margens do igarap? Esp?rito
Santo, entre Baiao e Tucuru?, Rio Tocantins, Bai?o/Tucuru?, Par?, 3?46?S 49?41?W, col. by
47
Expedi??o Permanente ? Amaz?nia, 11 September 1970; MZUSP 27637 (1), Rio Negro,
Pedra do Gavi?o, Moura, Amazonas, 1?28?S 61?38?W, col. by L.P.S. Portugal, 13
November 1982; MZUSP 34550 (1), Igarap? do Cujobim, Rio Branco, em frente da ilha de
Marac?, Roraima, 3?25?N 60?20?W, col. by M. Goulding, 13 November 1984; MZUSP
40478 (1), Rio Paran? (cachoeira), fazenda Olho d'?gua, Flores de Goi?s, Goi?s, 14?26?S
47?3?W, col. by J.C. Oliveira & W.J.M. Costa, 12 September 1988; MZUSP 52308 (1), Rio
Araguaia, Rio Tocantins, Mato Grosso; MZUSP 52327 (1), Rio Araguaia, Bandeirantes, Rio
Tocantins, Mato Grosso, 13?40?S 50?48?W; MZUSP 52342 (1), Rio Araguaia, Araguaiana,
Rio Tocantins, Mato Grosso, 15?43?S 51?51?W; MZUSP 54208 (1), Rio Araguaia, Ilha do
Bananal, GO, Mato Grosso; MZUSP 54539 (1), Rio Araguaia, s/ dados de localidade, Rio
Tocantins; MZUSP 86893 (2); MZUSP 87081 (3); MZUSP 87082 (4); MZUSP 89734 (1);
MZUSP 92720 (1); MZUSP 94085 (1); MZUSP 94415 (1); MZUSP 95627 (5); MZUSP
96132 (1); MZUSP 96598 (1); MZUSP 97217 (2); NMW 44073 (1) (Holotype: Plecostomus
annae Steindachner 1881), Par? [=Belem, Brazil]; USNM 191582 (1), Rio Araguaia, Near
Aruana, -14.967 -51.400, col. by H.R. Axelrod, 1960. Columbia: ANSP 146867 (1), Rio
Negrito at bridge on road joining Puerto Lopez and Vilavicencio; 200-400 yd downstream
of bridge, Meta, J.E.Bohlke et al., 15 March 1973; AUM 35432 (1), R?o Manac?as, Sandbar
on right (E) bank 31 airkm SSW Puerto Gaitan, Meta, J.S. Ramsey, R. J. Scully, M.C.
Blanco, et al., 10 October 1978. Guyana: ANSP 175912 (1), Esequibo River: 180 yd.
upstream from Esequibo campsite (Maipuri), Siparuni VIII-2, D. Alicock, 27 January
1997; ANSP 175913 (1), Esequibo River: sandbar ca.800 m downstream from Esequibo
campsite (Maipuri), Siparuni VIII-2, W.G.Saul, G.G.Watkins, N.R.Liley, C.Watson, 29
January 1997; AUM 35514 (1), Rupununi River 3.7 km SSE Masara, col. by J.W.
48
Armbruster, M.H. Sabaj, D.C. Werneke, C.L. Alison, M.R. Thomas, C.J. Chin, D. Arjoon,
S. Mario, S.M. James, 27 October 2002; AUM 35535 (2), Rupununi River 4.6 km NW
Masara, col. by J.W. Armbruster, M.H. Sabaj, D.C. Werneke, C.L. Alison, M.R. Thomas,
C.J. Chin, D. Arjoon, S.M. James, S. Mario, 26 October 2002; AUM 35551 (3), Rupununi
River at Kwatamang, 4 km SE Annai, col. by J.W. Armbruster, M.H. Sabaj, D.C. Werneke,
C.L. Alison, M.R. Thomas, C.J. Chin, D. Arjoon, S.M. James, 25 October 2002; AUM
35666 (2), Rupununi River at Karanambo, col. by J.W. Armbruster, M.H. Sabaj, D.C.
Werneke, C.L. Alison, M.R. Thomas, C.J. Chin, D. Arjoon; AUM 36611 (1), R?o
Macaruma, 134 km SE. of Cuidad Guiana, 5 km SE. of Guasipati, at old bridge just W. of
the main road, Bolivar, col. by J.W. Armbruster, D.C. Werneke, T.P. Pera, N.K. Lujan, and
O. Leon, 11 June 2003; AUM 38885 (1), Takutu River 3.77 km SSW Lethem, Reg. 9, col.
by J.W. Armbruster, M.H. Sabaj, M. Hardman, D. Arjoon, N.K. Lujan, L.S. de Souza, 1
November 2003; AUM 44344 (2), Esequibo River, shoreline and sandbeach downstream of
Kurukapari Fals and upstream from Iwokrama, Region 8, col. by L.S. deSouza, N.K. Lujan,
D.C. Taphorn, J.A. Hartsel, E. Liverpool, and S. Lord, 23 November 2005; AUM 45033
(1), Pond at Yukupari, Region 9, col. by N.K. Lujan, D.C. Taphorn, and E. Liverpool, 29
November 2005. Venezuela: ANSP 182988 (3), Rio Siapa (Casiquiare Dr.), raudale
Galineta, 142 km E of San Carlos de Rio Negro, M.H.Sabaj, D.C.Werneke, N.K.Lujan,
M.Arce, 17 March 2005; AUM 39309 (1), Rio Manapiare, 14.5 km NW of San Juan de
Manapiare, Amazonas, col. by N.K. Lujan, M.H. Sabaj, L.S. deSouza, and D.C. Werneke,
12 April 2004; AUM 39507 (1), Rio Ventuari, at Raudales Tencua, 56 km ESE of San Juan
de Manapiare, Amazonas, col. by D.C. Werneke, N.K. Lujan, O.Leon, A. Luna, and R.
Pajua; AUM 39836 (1), Rio Manapiare, 10 km NW of San Juan de Manapiare, Amazonas,
49
col. by N.K. Lujan, L.S. deSouza, D.C. Werneke, and M.H. Sabaj, 14 April 2004; AUM
39844 (1), Rio Ventuari, beach below Raudales Tencua, 56 km ESE of San Juan de
Manapiare, Amazonas, col. by N.K. Lujan, O. Leon, and R. Pajua; AUM 40579 (1), Rio
Orinoco, at Macuruco landing, 75 km E. of San Fernando de Atabapo, Amazonas, col. by
M.H. Sabaj, L.S. deSouza, D.C. Werneke, and N.K. Lujan, 4 April 2004; AUM 40751 (1),
R?o Ventuari, beach across the river from Picua Vilage, 34 km ENE of Macuruco, 104 km
E of San Fernando de Atabapo, Amazonas, col. by M.H. Sabaj, N.K. Lujan, D.C. Werneke,
L.S. deSouza, and O. Leon, 5 April 2004; AUM 41558 (2), Rio Manapiare, at Laja Pelada
landing, 27 km SSW of San Juan de Manapiare, Amazonas, col. by O. Leon, D.C. Werneke,
and N.K. Lujan, 18 April 2004; AUM 42092 (2), R?o Orinoco, beach, 16.1 km W of La
Esmeralda, Amazonas, col. by N.K. Lujan, M. Arce, E.L. Richmond , M.B. Grant, J.
Valadez, D. Brooks, and T.E. Wesley, 25 March 2005; AUM 42122 (2), R?o Orinoco, 33.9
km W of La Esmeralda, Punto Piaroa, Amazonas, col. by N.K. Lujan, M. Arce, T.E.
Wesley, M.B. G., E.L. R., J. B., D. B., 29 March 2005; AUM 42128 (1), R?o Casiquiare,
bedrock in stream, 73 km NE of San Carlos de R?o Negro, Amazonas, col. by N.K. Lujan,
D.C. Werneke, M.H. Sabaj, M. Arce, R. Betancur, and T.E. Wesley, 9 March 2005; AUM
42165 (3), R?o Orinoco, bedrock outcrop, 52.9 km SE of San Antonio, 102 km W of La
Esmeralda, Amazonas, col. by N.K. Lujan, D.C. Werneke, M.H. Sabaj, O. Leon, M. Arce,
R. Betancur, and T.E. Wesley, 4 March 2005; AUM 42182 (6), R?o Siapa, Raudales
Galineta, 142 km E of San Carlos de R?o Negro, Amazonas, col. by N.K. Lujan, D.C.
Werneke, M.H. Sabaj, O. Leon, M. Arce, and T.E. Wesley, 17 March 2005; AUM 42196
(1), R?o Casiquiare, bedrock outcrop, 59.5 km SW of La Esmeralda, Amazonas, col. by
N.K. Lujan, D.C. Werneke, M.H. Sabaj, M. Arce, R. Betancur, T.E. Wesley, and O. Santa
50
Ela, 8 March 2005; AUM 42199 (1), R?o Casiquiare, 153 km NE of San Carlos de R?o
Negro, Amazonas, col. by N.K. Lujan, O. Leon, M. Arce, E.L. Richmond, M.B. Grant, J.
Valadez, D. Brooks, and T.E. Wesley, 24 March 2005; AUM 42208 (1), R?o Ventuari, near
ornamental fish market in the river, Amazonas, col. by N.K. Lujan, M. Arce, E.L. R., M.B.
G., and T.E. Wesley, 3 March 2005; AUM 42222 (3), R?o Orinoco, near Puerto Ayacuho on
a beach caled Playa Bagre, Amazonas, col. by N.K. Lujan, M. Arce, and T.E. Wesley, 13
March 2005; AUM 42994 (2), R?o Orinoco, at Puerto Venado, 4.3 km S of Samariapo, 56.4
km SSW of Puerto Ayacucho, Amazonas, col. by N.K. Lujan, D.C. Werneke, M.H. Sabaj,
M. Arce, R. Betancur, and T.E. Wesley, 26 February 2005; AUM 43345 (3), R?o Casiquiare,
at mouth of Ca?o Caripo, 37 km WSW of La Esmeralda, Amazonas, col. by N.K. Lujan,
D.C. Werneke, M.H. Sabaj, O. Leon, M. Arce, R. Betancur, and T.E. Wesley, 5 March
2005; AUM 44971 (15), Esequibo River, at Kwaimata, beach in main channel and mouth
of side channel, Reg. 9, col. by L.S. deSouza, N.K. Lujan, D.C. Taphorn, J.A. Hartsel, E.
Liverpool, and S. Lord, 1 December 2005; INHS 29085 (1); INHS 34779 (1); MCNG 20045
(1); MCNG 21575 (1); MCNG 23800 (1); MCNG 28843 (1); MCNG 30360 (1); USNM
265664 (2), Rio Orinoco, Cove, Islote De Fajardo, 182 Naut. mi. Upstream From Sea Buoy,
Bolivar, 8.367, -62.700, col. by J. Baskin, D. Taphorn, 15 February 1978; USNM 269964
(2), Smal Cano Connecting With Rio Orinoco Immediately South of El Burro, Bolivar,
6.183 -67.417, co. by R.P. Vari, O. Castilo, C.J. Ferraris, 9 December 1984.
Isorineloricaria horridus: Bolvia: AMNH 77469 (2), Rio Mamore; 8 kilometers north of
Exaltacion, Depto Beni, Col. by S. Anderson, 29 September 1965; INHS 36997 (1), ;
USNM 305509 (2), Rio Curiraba @ 10 km NE El Porvenir Biol. Sta., @ 40 Air km E San
51
Borja, Dept. Beni, Balivia Prov., -14.917, -66.283, col. by W.C. Starnes, T.A. Monroe, J.
Sarmiento, et al., 31 August 1987. Brazil: AMNH 12604 (1), Vicinity of mouth of Rio
Macaua (tributary Rio Iaco), near Sena Madureira, 09?20?S, ca. 68?45?W, col. by B.A.
Krukoff, 1934; ANSP 8081 (1), (Holotype: Plecostomus scopularus, Cope 1871), Amazon
River, above the mouth of the Rio Negro, R. Perkins; MCZ 33518 (2), Rio Jurua [vicinity of
mouth of Rio Embira, trib. of Rio Tarauaca, in turn a trib. of Rio Jurua], Amazonas, col. by
B.A. Krukoff, 1934; MCZ 33524 (2), Rio Purus [vicinity of mouth of Rio Macaua, trib. of
Rio Iaco, in turn a tri. of Rio Purus], Acre, col. by B.A. Krukoff, 1933; MCZ 7794 (1), ;
MCZ 7799 (2), Tabatinga [Rio Solimoes at Tabatinga (aka Sapurara) and environs],
Amazonas, THAYER 133, col. by D. Bourget, 1865; MCZ 7802 (2), Lago Cudajas [Lago
Badajos], Amazonas, THAYER 025, col. by S.V.R. Thayer, D. Bourget, 1865; MCZ 7803
(2), Lago Manacapuru; Manacapuru [Lago Grande de Manacapuru], Amazonas, THAYER
060, col. by W. James, 1865; MCZ 7879 (3), Obidos; Obydos [Rio Amazonas at Obidos],
Par?, THAYER 076, col. by L. Agasiz and party, 26 August 1865; MZUSP 23260 (1), Rio
Solim?es, Amazonas, 4?5?S 63?9?W, Expedi??o Permanente ? Amaz?nia, 28 September
1968; MZUSP 28368 (2), Rio Machado, pr?ximo ? foz, Rond?nia, 8?4?S 62?54?W,
Expedi??o Permanente ? Amaz?nia, 21 November 1975; MZUSP 49682 (1), Rio Acre,
Seringal Bom Destino (1 hora acima de Porto Acre), Acre, 9?36?S, 67?32?W, 19 October
1994; MZUSP 49839 (1), Rio Acre, seringal Perseveran?a, Rio Purus drainage, Acre, ;
MZUSP 50374 (1), Rio Juru?, Colocac?o S?o Jo?o, Acre, 9?9?S, 72?41?W, 8 July 1993;
MZUSP 50377 (1), Rio Tejo, Ponto 13, Foz Baj?, Acre, 8?56?S 72?34?W, 8 March 1994;
MZUSP 50489 (1), Foz do S?o Jo?o, Rio Juru?, Acre, 9?9?S, 72?41?W, 18 July 1994;
MZUSP 50491(1), Foz do Breu, Rio Juru?, Acre, 9?25?S 72?43?W, 21 July 1994; MZUSP
52
50494 (1), Foz do Tejo, Rio Juru?, Acre, 8?58?S 72?42?W, 15 July 1994; MZUSP 57622 (1),
Rio Madeira, Amazonas, 3?49?54?S 59?3?58?W, col. by Zanata et al., 7 August 1996;
MZUSP 60372 (1), Rio Aripuan?, Porto de Balsa (rio acima), estrada que liga o distrito de
Colniza a Panelas, km 18, Aripuan?, Mato Grosso, 9?34?45?S 59?25?19?W, col. by F.
Machado, C.H. Melo, C.M.C. Leite & M.F. Catarino; USNM 041540 (1), Manacapouru;
USNM 308227 (2), Resaca Da Ilha De Marchantaria, Amazonas, col. by P. Bayley, 2
March 1977. Colombia: FMNH 96065 (5), Amazon River 1 mi. upstream from Leticia,
Amazonas, col. by Thomerson et al., 11 November 1973. Ecuador: USNM 177235 (1), Rio
Cotapino, Trib. of the Suno, -0.708, -77.342, col. by J. Olala, October 1950. Peru: ANSP
21280-83 (4), (Syntypes: Plecostomus virescens Cope 1874), Upper Amazon, col. by Prof.
James Orton; AUM 42001 (1), R?o Tahuamanu, road crossing in vicinity of San Lorenzo,
Madre de Dios, col. by M.H. Sabaj, L. Souza, M. Arce, L. deSouza, and N.J. Salcedo, 1
August 2004; AUM 45568 (1), R?o Nieva, 7.4 km SSW Juan Velasco (Sta Maria de Nieva),
Condorcanqui, Amazonas, col. by N.K. Lujan, D.C. Werneke, D.C. Taphorn, D.P. German,
and D. Osorio, 5 August 2006; AUM 45585 (1), R?o Mara?on, pongo above Borja, 35.5 km
NE Juan Velasco (Sta Maria de Nieva), Condorcanqui, Amazonas, col. by N.K. Lujan, D.C.
Werneke, D.C. Taphorn, A.S. Flecker, K.A. Capps, D.P. German, and D. Osorio, 6 August
2006; FMNH 70157 (1), Madre de Dios: Rio Inambari, col. by E.R. Blake, 6 October 1958;
INHS 36566 (1), ; INHS 36796 (1); INHS 55406 (1); MUSM 12628 (1); MUSM 19897 (1);
MUSM 26699 (1); MUSM 9976 (1); MZUSP 26754 (1), Rio Aguaytia, Nuevo Requena,
Pucalpa, col. by H. Ortega, 23 October 1973; MZUSP 26788 (1), Rio Neshuya, estrada
Pucalpa-Huanuco, Pucalpa, Ucayali, col. by H. Ortega, 24 July 1978; MZUSP 26789 (2),
Yarinacocha, Pucalpa, Cel. Portilo, Ucayali, col. by H. Ortega, 10 August 1973; UF
53
126268 (1), Cano Puinahua, opposite mouth of Rio Pacaya. Habitat - Beaches & Muddy
bottom, Loreto, col. by J.S. Albert et al., 23 September 2002; USNM 086834 (2),
Yurimaguas, Rio Paranapura, col. by W.R. Alen, November 1920; USNM 123268 (1), Rio
Morona, col. by W.R. Alen, October 1920; USNM 124911 (2), Shansho Cano, col. by
W.G. Scherer, 18 October 1935; USNM 167886 (1), Yurimaguas, Rio Hualaga, col. by
W.R. Alen, November 1920; USNM 167887 (2), Iquitos, Loreto Region, col. by W.R.
Alen, September 1920; USNM 167888 (1), Yurimaguas, Rio Paranapura, col. by W.R.
Alen, November 1920; USNM 263916 (3), Madre De Dios; Rio Tambopata, Opposite Boat
Landing For Explorer'S Inn., Madre de Dios Region, -12.833 S, -69.300 W, col. by H.
Ortega, R.P. Vari, 21 August 1983; USNM 263919 (1), Shore of Isla About 15 km
Downriver of Junction of Rio Tambopata and Rio Madre De Dios., Madre de Dios Region, -
12.500 S, -69.147 W, col. by R.P. Vari, H. Ortega, S.L. Jewet, 25 August 1983; USNM
350530 (1), Department Madre De Dios: Parque Nacional Manu, Pakitza and Vicinity,
Madre de Dios Region, col. by H. Ortega, October 1987. Unknown: ANSP 8279 (1),
Amazon River, col. by R.C. Perkins.
Isorineloricaria spinosisima: Ecuador: AUM 4251 (1); Los Rios, Rio Vinces, at Vinces,
col. by T. Roberts, R. Gilbert, and F. Silva M., 5 November 1971. FMNH 58546 (3); Rio
Duales, Colimes, A.W. Henn, 1913. FMHN 59369 (1); Guayaquil, A.W. Henn, 1913. MCZ
48773 (2); Fish market at Quevedo, 0?59?S 79?27?W, T.R. Roberts and party, 11 April 1971.
MCZ 51699 (2); Rio Vinces at Vinces, Roberts, Gilbert, and Silva, 11 May 1971. MSUM
2505.4.A (2).
54
Isorineloricaria tenuicauda: Syntypes: NMW 44265 (1); NMW 44266 (3). Nontype
material: Colombia: ANSP 71263 (Plecostomus winzi holotype) (1); Honda, Rio Magdalena
Basin, C. Miles, November 1940. CU 47928 (1), Lake San Sylvestre by city of Barranca-
Bermeja, Santander, col. by F. Archer, J.D. Archer, 20 August 1964; FMNH 55169 (3);
Soplaviento, Eigenmann. FMNH 76408 (1); Honda, Eigenmann. FMNH 76424 (1); Calamar
Cienega, Eigenmann. FMNH 96234 (1); Puerto del Rio, Magdalena River, Cienega on
Central Magdalena, M. Gonzales, 1913.
Isorineloricaria vilarsi: Venezuela: AUM 22584 (1); Zula, Lago Maracaibo, Southern part
of lake, Santa Barbara fish market, 20 December 1999. FMNH 6338 (4); Encontrados, N.
Dearborn, February 1908. MCNG 33523 (2); USNM 121019 (1); Rio Apon about 35km.
south of Rosario in Maracaibo basin, col. by L. Schultz, 26 February 1942. USNM 12120
(3); Rio Socuy 3km above mouth, Maracaibo Basin, col. by L. Shultz, 24 February 1942.
USNM 121021 (1); Rio Negro, 75km west of Rosario, col. by L. Shultz, 2 March 1942.
USNM 121022 (1); Cienaga del Guanavana about 10km. north of Sinamaica, col. by L.
Shultz, 11 March 1942. USNM 121031 (2); Lago Maracaibo, near mouth of Rio Concha,
col. by L. Schultz, 2 May 1942.
55
Figures
Fig. 1: Range of Loricariidae (from Armbruster 2004).
56
Fig. 2: Diagram of selected measurements, adapted from Boeseman (1968) and Armbruster
and Page (1996).
A. Sandard Length
B. Axial length
C. Total length
D. Predorsal length
E. Head length
F. Head- eye length
G. Orbit diameter
H. Snout length
I. Thoracic length
J. Pectoral spine length
K. Abdominal length
L. Pelvic spine length
M. Post-anal length
N. Anal fin length
O. Adipose spine length
P. Caudal depth
Q. Interdorsal length
R. Base of dorsal fin length
S. Dorsal spine length
T. Head depth
57
Fig. 3: Selected head measurements, adapted from Boeseman (1968) and Armbruster and
Page (1996).
Fig. 4: Illustration of caudal fin width measurement, adapted from Boeseman (1968) and
Armbruster and Page (1996).
A. Eye- nare length
B. Cleithral width
C. Internares width
D. Interorbital width
E. Snout? opercle distance
F. Snout? nares length
G. Caudal peduncle width
58
Fig. 5: Results of the PCA of the species of Isorineloricaria.
59
Fig. 6: Bivariate Fit of Snout-nares Wd. By Interorbital Wd. Red crosses- Isorineloricaria
horrida, Blue squares- I. emarginata.
Fig. 7: Bivariate Fit of Caudal Peduncle Dp. By Head L., black circles represent I.
spinosisima, red squares represent al other Isorineloricaria (except I. ammophila and I.
unicolor).
60
Fig. 8: A. Ventral view of mouth of Isorineloricaria gomesi, ANSP 69409, ilustrating the
large central buccal papila characteristic of most memebers of Isorineloricaria. Photograph
by M. Sabaj-Perez and K. Luckenbil. B. Ventral view of mouth of I. ammophila, AUM
22659, ilustrating multiple buccal pappilae found in I. ammophila and I. unicolor.
A B
61
Fig. 9: Dorsal, lateral, and ventral views of Isorineloricaria ammophila, AUM 22659.
62
Fig. 10: Dorsal and ventral views of Isorineloricaria n. sp. ?Apure?, INHS 35685 (holotype),
269.11mm SL.
63
Fig. 11: Lateral view of Isorineloricaria n. sp. ?Apure?, INHS 35685 (holotype), 269.11mm
SL.
64
Fig. 12: Dorsal, lateral, and ventral views of Isorineloricaria emarginata, MZUSP 97217,
227mm SL.
65
Fig. 13: Dorsal, lateral, and ventral views of Isorineloricaria gomesi, ANSP 69409
(holotype), 141.3mm SL. Photograph by Kyle Luckenbil.
66
Fig. 14: Dorsal, lateral, and ventral views of Isorineloricaria horrida, AUM 42001.
67
Fig. 15 A-C: Ventral (A), dorsal (B), and lateral (C) views of Isorineloricaria phrixosoma,
ANSP 68650, 109.5mm SL. Photographs taken by K. Luckenbil.
A B
C
68
Fig. 16: Dorsal, lateral, and ventral views of Isorineloricaria spinosisima, BMNH
1898.11.4.32 (syntype of Plecostomus festae), 357.6 mm SL. Photographs by C. Zawadzki.
69
Fig. 17: Lateral, dorsal, and ventral views of Isorineloricaria tenuicauda, MSNG 8856
(syntype). Photographs by M. Alen.
70
Fig. 18: Lateral, dorsal, and ventral view of Isorineloricaria unicolor, ZMA 116640
(Aphanotorulus frankei holotype), 105.4mm SL. Photographs by K.S. Cummings.
71
Fig. 19: Dorsal, lateral, and ventral views of Isorineloricaria vilarsi, USNM 121031,
301.5mm SL.
72
Fig. 20: Range map of Isorineloricaria ammophila and I. unicolor. Circles represent I.
ammophila, squares represent I. unicolor. Open shapes represent type localities. From
Armbruster (2008).
73
Fig. 21: Range map of Isorineloricaria n. sp. ?Apure?, I. gomesi, I. phrixosoma, I.
spinosisima, I. tenuicauda, and I. vilarsi. Squares represent Isorineloricaria n. sp. ?Apure?,
stars represent I. gomesi, X represents I. phrixosoma, circles represent I. squaliforma,
diamonds represent I. tenuicauda, and triangles represent I. vilarsi. Open shapes represent
type localities.
74
Fig. 22: Range map of Isorineloricaria emarginata.
75
Fig. 23: Range map of Isorineloricaria horrida. Type locality indicated by open square.
76
Table 1: Selected morphometrics of Isorineloricaria n. sp. ?Apure? and I. emarginata.
Isorineloricaria n. sp. ?Apure? Isorineloricaria emarginata
Measurement (m) N Average SD Range N Average SD Range
Standard Length (SL) 23 118.4 81.9 53.2 - 301.0 153 163.4 67.5 46.5 - 357.0
% SL
Predorsal L. 23 39.1 3.2 33.4 - 44.7 153 36.5 2.3 29.8 - 41.9
Head L. (HL) 23 32.9 3.9 20.9 - 36.7 153 29.8 2.5 23.3 - 36.2
Cleithral W. 22 26.1 1.4 23.2 - 28.3 153 23.8 1.5 20.0 - 27.2
Dorsal spine L. 21 29.4 4.6 18.4 - 34.8 153 -
Folded dorsal-fin L. 23 36.8 2.0 32.8 - 40.0 153 36.0 1.7 30.0 - 41.5
Dorsal-fin base L. 23 24.1 1.0 21.7 - 26.0 153 23.5 1.0 20.1 - 28.3
Dorsal- adipose L. 23 21.5 1.9 19.0 - 26.0 153 24.6 2.0 19.6 - 31.4
Thorax L. 23 23.0 1.5 20.4 - 26.2 153 23.6 1.4 20.0 - 27.5
Pectoral spine L. 23 28.6 2.0 24.6 - 32.6 153 25.4 2.1 18.8 - 31.4
Abdominal L. 23 19.1 1.0 16.9 - 20.5 153 20.3 1.1 16.5 - 24.8
Pelvic spine L. 23 22.7 2.1 17.4 - 25.8 153 20.1 1.8 14.1 - 25.6
Postanal L. 23 38.9 2.8 35.3 - 46.5 153 39.9 2.8 32.9 - 45.9
Caudal peduncle Dp. 23 8.1 0.6 6.7 - 9.0 153 7.2 0.6 5.7 - 8.9
Caudal peduncle W. 23 15.7 1.4 12.1 - 18.7 153 16.7 1.3 13.4 - 21.0
Adipose-fin spine L. 23 7.8 1.2 5.5 - 10.0 151 6.7 1.0 4.2 - 9.8
Anal-fin L. 23 13.2 2.2 9.6 - 17.7 153 12.0 1.6 6.8 - 17.5
Anal-fin base L. 23 4.0 0.5 2.6 - 4.8 152 4.0 0.5 2.3 - 5.3
Adipose- uper
caudal L. 23 20.9 1.2 18.5 - 22.8 152 20.4 1.2 17.0 - 23.5
Adipose- lower
caudal L. 23 26.7 1.4 22.7 - 29.0 153 24.8 1.3 20.4 - 28.2
%HL
Head Dp. 23 59.0 9.1 52.9 - 99.3 153 57.3 3.4 48.7 - 73.5
Snout L. 23 61.1 8.6 55.2 - 98.5 153 60.4 2.4 55.7 - 73.5
Orbit Diameter 23 20.9 5.6 14.0 - 41.1 153 19.4 3.0 14.4 - 36.5
Interorbital W. 23 44.7 7.2 39.2 - 76.6 153 38.5 2.0 34.1 - 44.3
Snout opercle D. 23 72.7 10.9 67.7 - 121.9 153 71.2 2.5 66.7 - 86.3
Head W. 23 81.3 11.2 72.7 - 131.0 153 80.3 3.4 72.0 - 97.3
Head eye L. 23 38.5 6.8 32.9 - 69.0 153 36.5 2.6 32.5 - 61.1
Eye nare L. 23 13.1 2.2 9.6 - 20.0 153 11.4 1.4 6.9 - 15.1
Internares W. 23 17.4 3.5 13.5 - 31.4 153 17.4 1.6 12.3 - 22.5
Snout nares L. 23 40.1 6.3 33.7 - 66.4 153 41.3 3.1 36.7 - 68.2
Snout pectoral L. 23 75.1 11.6 68.6 - 127.9 153 74.1 3.0 68.9 - 92.0
Pectoral orbit D. 23 25.5 5.0 20.1 - 42.6 153 27.1 3.5 19.1 - 37.0
Mouth W. 23 42.7 6.1 37.5 - 68.0 153 41.8 3.8 34.8 - 54.3
Mouth L. 23 45.7 7.4 40.2 - 77.7 153 43.4 3.7 33.3 - 59.7
Dentary L. 23 14.4 2.9 11.1 - 24.9 153 13.1 1.9 7.4 - 19.9
77
Table 2: Selected morphometrics of Isorineloricaria horrida and I. spinnosisima.
Isorineloricaria horida Isorineloricaria spinosissima
Measurement (m) N Average SD Range N Average SD Range
Standard Length (SL) 73 162.9 85.1 44.9 - 513.0 11 208.4 138.7 39.4 - 416.0
% SL
Predorsal L. 73 36.8 2.2 29.6 - 41.2 11 33.5 4.4 25.1 - 38.3
Head L. (HL) 73 30.2 2.3 23.5 - 38.8 11 27.9 4.4 19.9 - 33.7
Cleithral W. 72 24.8 1.8 19.2 - 27.6 11 22.3 3.3 16.3 - 25.6
Dorsal spine L. 73 - 11 27.3 3.8 19.9 - 31.3
Folded dorsal-fin L. 72 36.5 1.2 31.1 - 40.9 11 33.9 2.9 28.5 - 37.6
Dorsal-fin base L. 73 23.6 1.2 19.6 - 26.0 11 22.6 1.8 20.3 - 27.0
Dorsal- adipose L. 73 24.2 1.8 20.3 - 28.5 11 22.1 2.9 16.6 - 26.3
Thorax L. 73 24.2 1.6 19.2 - 28.7 11 21.4 1.8 18.4 - 23.6
Pectoral spine L. 72 25.9 2.3 18.1 - 30.3 11 22.2 4.6 15.1 - 28.5
Abdominal L. 73 20.2 1.2 18.0 - 24.8 11 18.3 1.2 16.7 - 20.4
Pelvic spine L. 73 20.8 2.4 14.7 - 26.0 11 20.2 2.6 14.9 - 23.8
Postanal L. 73 39.8 4.1 20.6 - 46.8 11 42.7 4.0 37.0 - 51.0
Caudal peduncle Dp. 73 7.8 0.9 5.6 - 9.1 11 5.2 1.1 3.7 - 6.6
Caudal peduncle W. 73 16.7 1.5 10.0 - 19.2 11 11.5 1.7 8.3 - 13.5
Adipose-fin spine L. 72 6.8 1.0 4.6 - 11.0 11 6.9 1.6 4.3 - 9.8
Anal-fin L. 72 13.2 1.7 10.4 - 17.9 11 13.7 1.2 11.8 - 15.4
Anal-fin base L. 72 4.1 0.6 1.9 - 5.8 11 4.1 1.0 2.2 - 5.9
Adipose- uper
caudal L. 73 21.2 1.6 16.6 - 24.7 11 26.0 2.3 22.8 - 29.5
Adipose- lower
caudal L. 72 25.7 1.3 22.7 - 28.9 11 28.7 2.3 26.1 - 33.4
%HL
Head Dp. 73 59.0 3.5 50.5 - 66.0 11 55.3 2.8 49.4 - 57.9
Snout L. 73 59.1 3.8 42.0 - 71.3 11 59.6 3.6 52.9 - 64.7
Orbit Diameter 73 17.9 2.4 11.7 - 24.2 11 18.5 3.9 14.7 - 27.4
Interorbital W. 73 43.5 3.9 30.0 - 49.5 11 37.7 1.6 33.5 - 39.5
Snout opercle D. 73 70.5 3.2 53.0 - 77.3 11 71.9 4.7 67.1 - 83.9
Head W. 73 82.6 3.4 67.4 - 90.4 11 80.2 3.7 76.2 - 86.3
Head eye L. 73 39.4 1.6 32.8 - 43.9 11 34.9 3.7 28.7 - 42.7
Eye nare L. 73 11.9 1.2 9.0 - 14.3 11 11.9 1.9 9.0 - 14.5
Internares W. 73 18.0 1.9 11.5 - 22.2 11 15.2 1.2 13.4 - 18.1
Snout nares L. 73 38.6 4.5 14.1 - 44.1 11 39.9 2.7 35.0 - 44.3
Snout pectoral L. 73 73.0 3.4 54.7 - 80.1 11 76.5 4.0 72.3 - 83.9
Pectoral orbit D. 73 27.2 2.8 20.3 - 34.2 11 27.9 4.0 22.7 - 36.7
Mouth W. 73 40.7 3.1 34.8 - 49.4 11 41.4 3.0 37.5 - 45.6
Mouth L. 73 41.9 3.5 30.4 - 47.8 11 44.2 4.4 37.4 - 51.9
Dentary L. 73 12.5 1.2 8.8 - 15.0 11 12.8 1.3 11.0 - 15.7
78
Table 3: Selected morphometrics of Isorineloricaria tenuicauda and I. vilarsi.
Isorineloricaria tenuicauda Isorineloricaria vilarsi
Measurement (m) N Average SD Range N Average SD Range
Standard Length (SL) 12 175.7 72.6 41.5 - 516.9 16 275.4 126.6 85.5 - 516.9
% SL
Predorsal L. 12 37.8 1.9 34.5 - 40.8 16 35.7 3.2 29.2 - 41.8
Head L. (HL) 12 32.4 2.4 28.6 - 37.8 16 29.4 3.2 24.0 - 36.1
Cleithral W. 12 25.4 1.3 22.6 - 28.0 16 22.9 2.4 19.1 - 26.7
Dorsal spine L. 10 32.1 2.2 28.3 - 35.0 15 27.8 5.6 13.8 - 34.1
Folded dorsal-fin L. 12 40.3 1.5 37.2 - 42.3 16 37.1 2.4 31.2 - 40.1
Dorsal-fin base L. 12 25.9 1.8 21.0 - 28.7 16 23.8 1.7 19.7 - 26.4
Dorsal- adipose L. 12 20.5 1.5 17.6 - 22.7 16 22.0 1.5 18.3 - 24.2
Thorax L. 12 24.3 1.3 22.1 - 26.1 16 22.9 1.6 19.1 - 25.8
Pectoral spine L. 12 30.8 2.6 24.4 - 34.0 16 26.2 2.0 23.4 - 30.7
Abdominal L. 12 20.4 0.8 19.4 - 21.8 16 20.2 1.3 18.0 - 22.7
Pelvic spine L. 12 22.0 1.9 17.7 - 25.2 16 20.2 1.7 16.4 - 23.4
Postanal L. 12 37.0 2.0 31.2 - 38.7 16 40.1 3.3 34.1 - 45.8
Caudal peduncle Dp. 12 8.2 0.7 6.8 - 9.2 16 7.4 1.0 6.3 - 9.1
Caudal peduncle W. 12 14.2 1.6 9.4 - 15.7 16 14.8 1.8 12.5 - 18.3
Adipose-fin spine L. 12 8.2 0.7 7.7 - 9.8 16 7.5 0.6 6.6 - 9.0
Anal-fin L. 12 16.0 1.2 14.0 - 18.0 16 14.6 1.8 10.6 - 16.9
Anal-fin base L. 11 4.4 0.6 3.2 - 5.5 16 4.5 0.5 3.6 - 5.3
Adipose- uper
caudal L. 12 23.1 1.1 21.3 - 25.1 16 21.1 1.8 16.9 - 23.3
Adipose- lower
caudal L. 12 26.6 1.2 24.7 - 28.5 16 25.0 1.5 21.1 - 26.6
%HL
Head Dp. 12 58.4 2.3 54.4 - 62.8 16 55.7 2.8 50.6 - 62.0
Snout L. 12 56.6 1.7 52.7 - 59.0 16 57.1 2.5 53.1 - 62.6
Orbit Diameter 12 15.8 2.3 12.7 - 19.1 16 13.7 3.3 10.2 - 22.7
Interorbital W. 12 43.1 1.7 40.2 - 45.8 16 42.6 1.8 38.9 - 45.8
Snout opercle D. 12 71.4 2.2 68.1 - 75.8 16 72.4 2.5 66.6 - 74.7
Head W. 12 81.4 4.1 71.5 - 86.9 16 79.4 2.5 74.6 - 85.6
Head eye L. 12 42.4 1.6 39.6 - 44.5 16 43.1 1.8 38.0 - 45.1
Eye nare L. 12 13.1 1.4 9.9 - 14.5 16 12.8 1.4 10.7 - 16.1
Internares W. 12 15.2 1.3 12.8 - 16.7 16 17.0 1.4 14.8 - 19.3
Snout nares L. 12 35.9 2.1 30.9 - 39.0 15 37.2 2.2 33.0 - 42.8
Snout pectoral L. 12 72.9 1.9 70.9 - 77.4 16 75.0 2.7 67.1 - 78.5
Pectoral orbit D. 12 27.0 2.2 21.4 - 29.1 16 28.6 2.0 24.5 - 31.0
Mouth W. 12 38.3 2.6 34.9 - 42.4 16 38.5 2.6 32.6 - 42.8
Mouth L. 12 43.1 2.7 39.0 - 47.2 16 42.3 2.5 38.6 - 46.8
Dentary L. 12 12.2 1.3 10.1 - 14.1 16 11.9 1.1 10.4 - 14.5
79
Table 4: Selected morphometrics of Isorineloricaria ammophila and I. unicolor.
Isorineloricaria amophila Isorineloricaria unicolor
Measurement (m) N Average SD Range N Average SD Range
Standard Length (SL) 91 81.5 27.9 36.0 - 160.9 323 84.1 17.4 31.1 - 139.0
% SL
Predorsal L. 91 91.0 1.6 36.1 - 44.0 319 38.3 1.1 35.6 - 43.8
Head L. (HL) 91 33.3 1.9 29.2 - 38.5 323 31.5 1.5 19.0 - 38.2
Cleithral W. 91 26.7 1.0 24.4 - 29.6 317 26.0 1.2 23.2 - 31.6
Dorsal spine L. 72 26.4 1.8 21.6 - 29.5 270 28.4 1.9 22.4 - 34.1
Folded dorsal-fin L. 90 33.8 1.1 30.9 - 36.9 315 33.7 1.4 20.1 - 37.6
Dorsal-fin base L. 91 19.6 1.2 17.2 - 22.8 323 19.3 1.2 15.6 - 23.9
Dorsal- adipose L. 91 20.9 1.6 16.8 - 24.1 322 23.2 1.5 16.9 - 26.5
Thorax L. 91 24.5 1.2 21.3 - 26.8 319 25.5 1.3 21.1 - 32.4
Pectoral spine L. 91 29.8 1.5 26.0 - 33.8 322 28.6 1.4 25.0 - 32.1
Abdominal L. 91 21.7 1.0 19.2 - 24.4 319 23.1 1.0 20.0 - 25.5
Pelvic spine L. 91 19.3 1.0 17.1 - 22.5 318 20.8 1.0 16.4 - 24.2
Postanal L. 91 29.6 1.1 26.2 - 31.8 319 30.3 1.3 26.8 - 35.6
Caudal peduncle Dp. 91 7.0 0.4 5.7 - 8.3 323 8.2 0.6 5.9 - 9.6
Caudal peduncle W. 90 12.9 1.0 9.7 - 16.1 317 14.7 1.4 10.6 - 17.9
Adipose-fin spine L. 90 8.5 0.9 5.7 - 10.6 315 8.3 0.8 6.6 - 10.8
%HL
Head Dp. 91 46.5 4.0 36.7 - 55.4 317 51.9 8.1 35.0 - 100.6
Snout L. 91 51.1 2.9 43.4 - 56.8 321 51.0 6.6 40.2 - 147.9
Orbit Diameter 91 13.7 1.7 10.2 - 20.7 321 17.4 2.1 12.1 - 32.8
Interorbital W. 91 34.1 2.4 25.7 - 39.5 323 34.6 6.7 28.0 - 139.7
Snout opercle D. 91 69.4 2.3 62.5 - 77.9 321 68.6 3.7 57.9 - 87.3
Head W. 91 78.9 3.9 66.7 - 88.8 321 80.6 6.2 67.6 - 145.0
80
Table 5: Selected morphometrics of Isorineloricaria gomesi and I. phrixosoma.
Isorineloricaria gomesi Isorineloricaria phrixosoma
Measurement (m) Holotype Holotype
Standard Length
(SL) 143.6 109.5
% SL
Predorsal L. 38.3 38.1
Head L. (HL) 31.1 31.6
Cleithral W. 24.2 26.5
Dorsal spine L. -
Folded dorsal-fin L. 35.5 35.4
Dorsal-fin base L. 20.9 20.8
Dorsal- adipose L. 25.6 24.3
Thorax L. 21.7 24.2
Pectoral spine L. 25.9 28.0
Abdominal L. 19.2 20.4
Pelvic spine L. 19.6 24.3
Postanal L. 35.3 39.9
Caudal peduncle
Dp. 6.4 8.5
Caudal peduncle
W. 14.7 15.0
Adipose-fin spine
L. 6.1 7.7
Anal-fin L. 12.0 13.6
Anal-fin base L. 4.4 4.3
Adipose- uper
caudal L. 18.7 22.1
Adipose- lower
caudal L. 22.8 27.5
%HL
Head Dp. 52.4 56.0
Snout L. 58.1 61.0
Orbit Diameter 17.6 17.5
Interorbital W. 40.3 40.5
Snout opercle D. 57.8 72.6
Head W. 78.5 82.7
Head eye L. 37.6 35.8
Eye nare L. 11.2 10.5
Internares W. 16.7 17.4
Snout nares L. 38.2 41.3
Snout pectoral L. 72.3 75.5
Pectoral orbit D. 27.4 27.7
Mouth W. 36.6 43.5
Mouth L. 38.9 45.3
Dentary L. 12.7 16.1