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A New Species of the Neotropical Catfish Genus
Trichomycterus (Siluriformes: Trichomycteridae)
Representing a New Body Shape for the Family
Wolmar Benjamin Wosiacki
1
and Ma´rio de Pinna
2
Trichomycterus crassicaudatus is described as a new species from the Rio Iguac¸u basin in southern Brazil. The new
species has an exceptionally deep posterior region of the body (caudal peduncle depth 22.8–25.4% SL), resulting
in an overall shape which distinguishes it at once from all other members of the Trichomycteridae. The caudal
fin of the species is broad-based and forked, a shape also distinguishing it from all other species in the family. A
number of autapomorphic modifications of T. crassicaudatus are associated with the deepening of the caudal
region, including an elongation of the hemal and neural spines of the vertebrae at the middle of the caudal
peduncle. Phylogenetic relationships of the new species are yet unresolved, but it shares a similar color pattern
and a thickening of caudal-fin procurrent rays with T. stawiarski, a poorly-known species also from the Rio Iguac¸u
basin. Coloration and body shape also include similarities with T. lewi from Venezuela.
T
HE genus Trichomycterus is the largest in the
family Trichomycteridae, with approximately 100
nominal species and probably numerous others
still undescribed. The genus is not demonstrably a mono-
phyletic group (de Pinna, 1998), and its latest taxonomic
revision is almost 90 years old (Eigenmann, 1918). Despite
basic taxonomic problems, new species of Trichomycterus
are often described (Bockmann et al., 2004; Wosiacki
and Garavello, 2004; Ferna´ndez and Schaefer, 2005), a task
which is often complicated by myriad nomenclatural
problems related with already-named yet incompletely-
diagnosed forms.
Some species assignable to Trichomycterus, however, are so
distinctive that they can be easily diagnosed from all other
species by one or more clearly defined characters, without
the need for wide-ranging revisionary studies or fine-scale
population analyses. Such is the case reported in the present
paper.
Herein, we describe a new species from the Rio Iguac¸u
drainage in Brazil with a remarkable set of characteristics
which set it apart from all other currently known species of
Trichomycterus. In external aspect, this is perhaps the most
distinct species of the genus yet found and represents a body
shape previously unknown for trichomycterids. Such a
unique condition is mostly a result of the pronounced
expansion of the caudal peduncle and caudal fin, which are
associated with a host of modifications in internal anatomy.
Under traditional concepts of trichomycterid taxonomy,
such major phenetic divergence might indicate a separate
genus for our new species. However, as discussed below,
inclusion of the new species in Trichomycterus seems to be
the most sensible action at the moment. The striking aspect
of the present new species is a result of autapomorphic
modifications only, and does not reflect a special position in
trichomycterid phylogeny.
The new species comes from the Rio Iguac¸u Basin, which
drains a large area of southern Brazil and Argentina. This is
the ninth species of Trichomycterus recorded for the Rio
Iguac¸u Basin above the Iguac¸u waterfalls (the others being T.
stawiarski, T. castroi, T. naipi, T. papilliferus, T. mboycy, T.
taroba, T. plumbeus, and T. davisi, the latter also occurring in
the Rio Ribeira de Iguape Basin).
MATERIALS AND METHODS
All measurements were taken point-to-point with calipers
on the left side of specimens. Caudal-peduncle length was
measured from the last anal-fin ray base to the middle of the
caudal-fin base; caudal-peduncle depth was taken at the
vertical through the middle of its length; distance between
pelvic-fin base and anus was measured from the base of the
inner pelvic-fin ray and anterior margin of the anus;
supraorbital pore distance was the distance between contra-
lateral S6 pores; mouth width was measured between
internal corners of mouth. Other measurements followed
Tchernavin (1944). Dorsal and anal-fin ray counts included
all branched rays plus all unbranched rays visible in
transmitted light. The numbering of pores of the supra-
and infraorbital sensory canals followed Arratia and Hua-
quin (1995).
Osteological observations were made on specimens
cleared and counterstained (CS) for cartilage and bone
according to a modified version of the method of Dingerkus
and Uhler (1977). Radiographs of specimens were prepared
with a Faxitron digital x-ray system, model MX-20. The
Weberian complex and compound caudal centrum were not
included in vertebral counts. Numbers of vertebrae and
pleural ribs were taken from cleared and stained prepara-
tions and radiographs of alcoholic specimens.
Institutional abbreviations follow Leviton et al. (1985),
with the addition of NUP, Nu´ cleo de Pesquisa em Limno-
logia, Ictiologia e Aqu¨icultura, Maringa´, Brazil; and MHNCI,
Museu de Histo´ ria Natural ‘‘Capa˜o da Imbuia,’’ Curitiba,
Brazil.
1
Museu Paraense Emı´lio Goeldi, Av. Magalha˜es Barata, 376, Bele´m, PA, Brazil, CP 399, 66040-170; E-mail: wolmar@museu-goeldi.br. Send
reprint requests to this address.
2
Department of Vertebrates, Museu de Zoologia da Universidade de Sa˜o Paulo, Sa˜o Paulo, Brazil, CP 42594, 04299-970; E-mail:
pinna@ib.usp.br.
Submitted: 4 October 2006. Accepted: 18 October 2007. Associate Editor: C. J. Ferraris.
F 2008 by the American Society of Ichthyologists and Herpetologists
DOI: 10.1643/CI-06-237
Copeia 2008, No. 2, 273–278
Trichomycterus crassicaudatus, new species
Figures 1, 2; Table 1
Holotype.—MZUSP 88518, 108.8 mm SL, Brazil, Estado do
Parana´, Rio Jorda˜o at Municı´pio de Foz do Jorda˜o, near
border with Municı´pio de Reserva do Iguac¸u, 28 May 1996,
NUP team.
Paratypes.—MZUSP 88519, 105.6 mm SL, and MPEG 7931,
113 mm SL, same locality and collectors as holotype, 29 July
1996; MZUSP 88517, 2, 110.9–121.3 mm SL; MHNCI 7908,
105.2 mm SL, stained disarticulated skeleton, Brazil, Estado
do Parana´, Municı´pio de Candoi, Rio Jorda˜o, ca. 2 km
upstream from mouth on Rio Iguac¸u, 20 Oct. 1991, W. B.
Wosiacki, E. S. Grando, and A. C. Carrillo; MPEG 13057,
34.1 mm SL, and MPEG 13058, 56.6 mm SL, Brazil, Estado
do Parana´, municı´pio de Cando´ i, Rio Jorda˜o, Rio Iguac¸u
Basin, no date, NUP team.
Non-type material.—NUP 3783, 3, 78.6–134.5 mm SL, Brazil,
Estado do Parana´, Rio Jorda˜o above the hidroelectric dam of
Santa Clara, Municı´pio de Candoi, Pinha˜o, April 2005, NUP
team; NUP 4006, 3, 107.5–114.3 mm SL, same data as NUP
3783.
Diagnosis.—Trichomycterus crassicaudatus, new species, is
distinguished from all other species in the Trichomycteridae
by the deep posterior region of the body, including the
caudal peduncle and caudal fin (caudal-peduncle depth
22.8–25.4% SL in adults). Trichomycterus crassicaudatus also
differs from all congeners by the shape of the caudal fin in
adults, in which the fin is prolonged into long, markedly
diverging and somewhat irregular lobes forming a concave
posterior margin. In other species of Trichomycterus, the
caudal fin is either truncate, emarginate, or round. Another
characteristic which sets T. crassicaudatus apart from all
other congeners and possibly all other trichomycterids is the
pronounced elongation of the neural and hemal spines of
the caudal vertebrae along the mid-portion of the caudal
peduncle (see Discussion). Trichomycterus crassicaudatus is
further distinguished from all other trichomycterids, except
T. stawiarski, by its thicky-ossified and rigid procurrent
caudal-fin rays, markedly distinct from the flexible and
splint-like procurrent rays in other trichomycterids. The
coloration pattern of T. crassicaudatus, composed of closely-
set large irregular blotches overlain by a more superficial
layer of small round markings, distinguishes it from the
majority of other species currently in Trichomycterus, but not
T. stawiarski. Other characteristics which could not be
checked in all species of Trichomycteridae but which may
be useful to identify T. crassicaudatus include the urohyal
foramen reduced to a slender canal and the presence of 5–7
lateral line pores (figures overlapping with those in Bullockia
maldonadoi and Hatcheria macraei).
Description.—Morphometric data for the holotype and
paratypes given in Table 1. Body elongate, cylindrical at
pectoral girdle, gradually becoming compressed along trunk
and caudal peduncle until caudal-fin base. Ventral and
dorsal profiles of body slightly convex and straight along
caudal peduncle. Dorsal-fin base situated in a depression of
dorsal profile of body (Fig. 1).
Integument thick, especially over base of dorsal, anal, and
pectoral fins. Small papillae present over body, visible only
under stereomicroscope. Larger papillae over lips and
mental region.
Head broad, slightly longer than wide, ellipsoid in
transverse section at level of eyes (Fig. 2). Dorsal profile of
head straight or slightly convex, ventral profile straight.
Head triangular in dorsal view. Snout slightly rounded in
dorsal view. Interorbital region flat. Lateral region of head
swollen by well-developed jaw muscles in contact with
margin of eye. Eye small, round, dorso-laterally oriented,
anterior and posterior margin equidistant from those of
contra lateral eye. Orbital rim not free. Skin covering eye
thin and transparent, distinctly separate from surface of
eyeball. Anterior nostril smaller than eye and larger than
posterior nostril. Anterior nostril surrounded by fleshy flap
of integument, posterolaterally continuous with nasal
barbel. Posterior nostril partially surrounded anteriorly,
laterally and medially by thin but long flap of skin.
Branchial membranes thick, united to isthmus anteriorly.
Gill opening wide. Eight or nine branchiostegal rays,
covered with thick skin. Mouth subterminal, with corners
posterolateraly oriented. Upper and lower lips thick, upper
lip more so anteriorly; both lips covered with conspicuous
papillae. Lower lip with large fleshy lobes, medial to origin
of rictal barbels.
All barbels with wide flat bases; gradually narrowing
distally. Nasal barbel thick and moderately long, reaching
Fig. 1. Trichomycterus crassicaudatus, holotype, MZUSP 88518, 108.8 mm SL, left lateral view.
274 Copeia 2008, No. 2
beyond posterior margin of eye. Origin of nasal barbel on
posterolateral portion of integument flap around anterior
nostril. Maxillary and rictal barbels thick and short, both
reaching to or slightly beyond vertical through posterior
margin of eye. Pectoral fin wide, with i+7 rays and gently
convex distal margin; first and second rays longest; first one
(unbranched) thick, not prolonged as filament. Dorsal fin
with iv+8 rays (three anterior ones vestigial, and visible only
in radiographs), second and third branched rays longest.
Anal fin with iv+6 rays (three anterior ones vestigial, and
visible only in radiographs) as long as dorsal fin; base of first
anal-fin ray at vertical through base of seventh dorsal-fin
ray, second and third longest. Pelvic fin with i+4 rays, first
and second rays longest; its base anterior to vertical through
dorsal-fin origin; tip of fin reaching urogenital opening. In
adult specimens, caudal fin forked with dorsal lobe longer,
both lobes with round tips; juvenile specimens (56.6 mm SL
and under) with truncate or emarginate caudal fin; 6/7
principal caudal-fin rays. Procurrent caudal-fin rays 24–26
dorsally (holotype 25) and 17 or 18 ventrally (holotype 17).
Opercular patch of odontodes small, with 15 or 16 short,
thin, straight odontodes with thickened tips. Interopercular
patch with 19–22 short, thin, conic, and straight odontodes
arranged in two irregular series (12+ 10).
Cephalic sensory canals including complete supraorbital
canal and incomplete infraorbital canal. Infraorbital restrict-
ed to posterior region corresponding to pores i10 and i11.
Supraorbital pores S1, S3, and S6. Two paired pores S6.
Laterosensory canal reduced on trunk, comprising four to
seven lateral-line pores, fourth pore at vertical through
middle of pectoral fin.
Free vertebra 35 or 36 (holotype 35). Ribs 11 pairs, first
thickest, ninth and tenth longest, in some specimens an
extra rudimentary rib posteriorly. Dorsal-fin pterygiophores
eight, first one inserting anterior to neural spine of 15
th
to
17
th
free vertebra (holotype 16
th
). Anal pterygiophores six,
first one anterior to hemal spine of 19
th
to 21
st
free vertebra
(holotype 20
th
). Two separate hypurals on upper hypural
plate; parahypural and hypurals one and two fused on lower
plate.
Color pattern in ethanol.—Dark pigmentation on body clearly
disposed in distinct and overlapping layers of integument.
Deep layer composed of several large dark spots of variable
size and irregular shapes, more concentrated on dorsum of
trunk; spots gradually becoming more scattered and smaller
on sides and absent on ventral part of abdomen and head.
Superficial layer with small rounded spots forming a uniform
freckle over sides and dorsum of body, more concentrated on
dorsum of trunk. Deep-layer spots, smaller than those on
body, entering dorsal head region, more concentrated on
Table 1. Morphometric Data from Trichomycterus crassicaudatus, New
Species. 1. SL is in mm. Measurements 2 to 15 expressed as proportion of
SL and 16 to 24 as proportions of HL. n 5 6.
Holotype Min. Max. Mean
1. Standard length (SL; mm) 108.8
2. Head length (HL) 23.7 21.4 23.8 23.0
3. Predorsal length 66.7 61.7 68.8 66.8
4. Prepelvic length 60.4 56.4 62.3 60.0
5. Preanal length 70.3 70.3 75.4 73.0
6. Scapular girdle width 19.7 16.9 19.7 18.6
7. Trunk length 39.1 36.3 43.9 39.2
8. Pectoral-fin length 15.4 10.8 15.4 13.8
9. Pelvic-fin length 10.3 9.0 10.3 9.6
10. Distance between pelvic-fin
base and anus
6.6 5.8 9.3 7.1
11. Caudal peduncle length 22.6 17.4 22.6 19.4
12. Caudal peduncle depth 24.2 22.8 25.4 24.2
13. Body depth 29.8 24.8 29.8 26.8
14. Dorsal-fin length 13.6 10.0 13.6 11.9
15. Anal-fin length 8.1 6.7 10.0 8.2
16. Head width 95.3 84.7 95.3 90.5
17. Nasal barbel length 36.4 33.1 42.5 36.8
18. Maxillary barbel length 40.7 27.7 40.7 33.3
19. Rictal barbel length 40.7 25.4 40.7 34.5
20. Snout length 55.0 43.9 55.0 48.4
21. Interorbital 31.4 22.1 31.4 26.1
22. Mouth width 32.9 30.3 37.5 33.6
23. Eye diameter 8.5 8.0 9.7 8.9
24. Supra-orbital pore distance 6.2 5.7 8.5 7.2
Fig. 2. Head of Trichomycterus crassicaudatus, holotype, MZUSP
88518, 108.8 mm SL: (A) Lateral view; (B) dorsal view; (C) ventral view.
Wosiacki and de Pinna—New Trichomycterus 275
occipital and interorbital region. Lateral surface of head with
small spots irregularly distributed, slightly lighter than dorsal
region. Odontode areas in both opercle and interopercle
white, in stark contrast to remainder of head. Upper lip with
uniform gray covering. Lower lip without dark pigment.
Dorsal fin with spots over fin rays, most dense at base and
along anterior edge of fin and fading gradually to margin. In
some specimens, spots on dorsal fin arranged as faint stripe
across middle of fin. Pigmentation of anal fin similar to that
of dorsal fin, but lighter. Pectoral fin with irregular dark
covering over basal portion of dorsal surface, fading gradually
distally. Pelvic fin with sparse spots, mainly along anterior
edge. Caudal fin uniformly covered with small dark spots, in
some specimens roughly arranged in one or more irregular
vertical lines. Nasal barbel with both surfaces darkly-pig-
mented. Maxillary and rictal barbels dark dorsally, more
markedly so in former, and white ventrally.
Habitat.—The Rio Iguac¸u Basin (Fig. 3) drains an area of
72,000 km
2
in Brazil and Argentina (Maack, 1981) with an
extensive waterfall section starting 22 km upstream from its
mouth, composing a complex of over 200 cataracts, the
largest being 72 m high, but with several others in the 30
and 40 m range (Maack, 1981). The waterfalls constitute an
efficient geographic barrier for all species of fishes inhabit-
ing the basin, and are associated with a high degree of
endemism above the falls (F. A. Sampaio, pers. comm.).
Some of the paratypes of T. crassicaudatus were collected
by WBW from a tributary of the Rio Iguac¸u, Rio Jorda˜o,
around two kilometers upstream from its mouth. The river
at that point is 100 m wide and maximally 2 m deep. The
substrate is composed of angular basaltic rocks and pebble.
The site is now submerged by an artificial dam. Those three
specimens were trapped at the upper part of a gill net in a
sector of the river with strong current and 1.2 m depth. The
presence of Trichomycterus species in fast-running water is
common (Arratia, 1983; pers. obs.), but the specimens are
usually found near the substrate, between boulders and
pebbles, protected from the strong current. None of the
collections so far allow a definite determination of water
depth and microhabitat preference of T. crassicaudatus. The
peculiar caudal morphology of the species may be associated
with some form of pelagic habit, but that still requires
further information.
Etymology.—The specific epithet is from the Latin crassus,
meaning thick, cauda, for tail, and atus, to posses. In allusion
to the deep caudal peduncle.
DISCUSSION
Within the subfamily Trichomycterinae, the only other
taxon which compares with Trichomycterus crassicaudatus in
phenotypic divergence of external aspect is Rhizosomichthys
totae, from Colombia. Under traditional concepts of tricho-
mycterid taxonomy, such major phenetic divergence might
indicate a separate genus for our new species, as was the case
with the monotypic Rhizosomichthys. However, preliminary
phylogenetic considerations discussed below indicate that
such a move would be unjustified. The peculiar aspect of T.
crassicaudatus is a result of autapomorphic divergence only,
and the species seems to be phylogenetically nested within a
group of species currently in the genus Trichomycterus.
The character combination displayed by T. crassicaudatus
indicates clearly that the species is neither a basal (Tricho-
geninae, Copionodontinae) nor a distal (Glanapteryginae,
Sarcoglanidinae, Tridentinae, Stegophilinae and Vandellii-
nae) trichomycterid, and such components of relationships
can be confidently excluded from consideration on the basis
of a straight reading of character evidence available in the
literature (de Pinna, 1998). Trichomycterus crassicaudatus,
therefore, fits the Trichomycterinae, a large phylogenetical-
ly-intermediate assemblage of doubtful monophyly. There-
in, T. crassicaudatus also lacks the known synapomorphies
for each of Bullockia, Eremophilus, Hatcheria, Ituglanis,
Scleronema, and Silvinichthys proposed by Arratia (1990,
1998), Costa and Bockmann (1993), and Ferna´ndez and de
Pinna (2005). With those possibilities excluded, the new
species is therefore assigned to the large waste-basket genus
Trichomycterus, again an assemblage of questionable mono-
phyly. Such positioning is not entirely satisfactory and is an
unavoidable result of current lack of resolution in the
relevant portion of the trichomycterid tree. However,
inclusion of the new species in Trichomycterus is presently
the best possible one, and any alternative generic placement
will require further knowledge on trichomycterine phylog-
eny. Within Trichomycterus, the position of T. crassicaudatus
can at present only be speculated on the basis of a few
potentially informative characters. Its color pattern, com-
posed of large dark blotches with a markedly irregular shape,
is very similar if not identical, to that of another endemic to
the Rio Iguac¸u, T. stawiarski. The two species also share a
thickening of the procurrent rays of the caudal fin, where
those structures are rigid and spine-like. This contrasts with
the putatively plesiomorphic condition in trichomycterids
which is to have thin, splint-like flexible procurrent rays,
present in the majority of species in the family, as well as in
Nematogenyidae. The color pattern in T. crassicaudatus also
superficially resembles the condition seen in T. lewi,
described a few years ago from the Rio Kukena´n, Orinoco
drainage, Guyana shield in Venezuela (Lasso and Proven-
zano, 2002). However, in T. lewi the large dark blotches on
the body are round and with well-defined borders, different
from the irregular-shaped and poorly-defined ones in T.
crassicaudatus and T. stawiarski. Trichomycterus lewi also
seems to have the deepest caudal peduncle in Trichomycterus
other than for T. crassicaudatus (see fig. 7 in Lasso and
Provenzano, 2002). The precise meaning of such observa-
tions, however, is still uncertain and a resolution of the
phylogenetic position of T. crassicaudatus will have to await
Fig. 3. Map of southern Brazil showing the type locality of Trichomyc-
terus crassicaudatus, new species. Black circle represents type locality
and more sites.
276 Copeia 2008, No. 2
an extensive phylogenetic analysis including most other
species currently included in Trichomycterus. Likewise, we
cannot at this time be conclusive as to the possible inclusion
of the species in the so called Trichomycterus brasiliensis
species-complex originally proposed by Costa (1992) and
later discussed by Barbosa and Costa (2003) and Bockmann
and Sazima (2004). While the character variation recorded
in association with the recognition of the Trichomycterus
brasiliensis species-complex is certainly real, much work
remains to be done on determining states of the relevant
characters among the several poorly-known species in the
genus from throughout South America. In any event,
Trichomycterus crassicaudatus has two of the four characters
considered as valid evidence for the monophyly of the
Trichomycterus brasiliensis species-complex by Bockmann
and Sazima (2004), the close proximity of the pelvic-fin
bases, and an integumentary color pattern formed by dark
pigmentation distinctly arranged in two different layers of
integument, a condition previously observed by de Pinna
(1992) in T. castroi.
The peculiar body shape of Trichomycterus crassicaudatus
includes evident autapomorphic modifications of the
species. The depth of its caudal peduncle is the most
extreme in trichomycterids and the anatomical modifica-
tions associated with it include an elongation of the neural
and hemal spines of the caudal vertebrae at the mid-portion
of the caudal peduncle. The length of hemal and neural
spines markedly increases posterior to the last anal and
dorsal pterygiophores, respectively, and then shorten again
gradually towards the caudal fin. The longest hemal spines
are those associated with preural vertebrae 9 to 11 and the
longest neural ones are on preural vertebrae 10 to 13. In
both series, the longest spines are approximately 33% longer
than those immediately posterior to the last pterygiophore.
Also related to the deepening of the caudal peduncle region
is the marked posterior increase in length of the procurrent
caudal-fin rays (Fig. 4). Both traits, at least to such a degree,
are unique in Trichomycteridae. The shape of the caudal fin
in T. crassicaudatus provides another autapomorphy for the
species. A forked caudal fin is not present in any other
species of Trichomycterus and is derived within trichomyc-
terids, since most basal members of the family, Trichogen-
inae and Copionodontinae, as well as in the Nematogenyi-
dae, have truncate, round or emarginate caudal fins.
Although forked caudal fins also occur in a few species of
other, distantly-related, trichomycterid subfamilies such as
Stegophilinae (Pareiodon microps, Parastegophilus maculatus,
Henonemus taxistigmus, H. punctatus, H. macrops and Pseu-
dostegophilus spp.) and Vandelliinae (Vandellia wieneri), in
none of those the morphological similarity to T. crassicau-
datus goes beyond the mere bifurcation. The forked caudal
fin in T. crassicaudatus is unique in the broad marginal
concavity that separates the upper and lower lobes. Juveniles
of the species have a truncate or emarginate caudal fin,
which further corroborates the apomorphic condition of the
fin morphology in adults.
MATERIAL EXAMINED
Nematogenyidae. Nematogenys inermis, UFRGS 3955, 1 CS.
Trichomycteridae. Copionodontinae: Copionodon pecten,
MZUSP 42462, 10, 3 CS; Glaphyropoma rodriguesi, MZUSP
42466,3,1CS.Trichogeninae:Trichogenes longipinnis,
MZUSP 63478, 3 CS. Trichomycterinae: Bullockia maldona-
doi, MZUSP 36958, 1 CS; Eremophilus mutisii, MZUSP 35409,
1 CS, AMNH 56092, 1 CS; E. candidus (paratypes), MZUSP
11762, 5, 2 CS; Hatcheria macraei, MZUSP 35687, 2 CS;
Ituglanis proops, MZUSP 36502, 7, MZUSP 46902, 2, MZUSP
39027, 2; Ituglanis sp., MNRJ 11489, 13, 5 CS; Scleronema
minutum, MCP 11169, 13 CS; S. operculatum, MCP 9315, 1
CS; T. brasiliensis, MPEG 13153, 12, 2 CS; T. castroi, MHNCI
7881, 1 CS, MHNCI 7643, 1; T. davisi, MCP 10646, 2 CS,
MZUSP 38783, 34; T. iheringi, MHNCI 7916, 8, 1 CS; T.
mboycy, MPEG 6695, holotype; T. mimonha, MZUSP 34344,
4, MCP 18021, 5; T. naipi, MPEG 6699, holotype, MZUSP
38788, paratypes, 2; T. nigricans, MCP 10649, 1 CS; T.
papilliferus, MPEG 6692, holotype; T. plumbeus, MPEG 6686,
holotype; T. rivulatus, ROM 403409, 6, 1 CS; T. stawiarski,
MZUSP 94835, 2, MZUSP 94836, 2, MZUSP 94837, 2; T.
taroba, MPEG 6689, holotype.
ACKNOWLEDGMENTS
WBW thanks Sociedade de Pesquisa em Vida Selvagem e
Educac¸a˜o Ambiental for the invitation to work in the type
locality of Trichomycterus crassicaudatus and the Zoology
graduate program at Universidade Federal do Parana´ for
logistic help. The authors thank V. Abilho
ˆ
a (MHNCI) and C.
Pavanelli (NUP) for the loan of specimens and L. Sousa for
help with photographs. Research funding was provided by
Conselho Nacional de Desenvolvimento Cientı´fico e Tecno-
lo´gico, Fundac¸a˜o de Amparo a` Pesquisa do Estado de Sa˜o
Paulo, Lakeside Foundation (CAS), and by the Programa de
Pesquisa em Biodiversidade from the Ministe´rio da Cie
ˆ
ncia e
Tecnologia, Brazilian government.
LITERATURE CITED
Arratia, G. 1983. Preferencias de habitat de peces Siluri-
formes de aguas continentales de Chile (Fam. Diplomys-
tidae y Trichomycteridae). Studies on Neotropical Fauna
and Environmental 18:217–237.
Arratia, G. 1990. The South American Trichomycterinae
(Teleostei: Siluriformes), a problematic group, p. 395–403.
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