Two new species of the catfish genus Trichomycterus ( Siluriformes : Trichomycteridae ) from the rio Ribeira de Iguape Basin , Southeastern Brazil

Two new species of the trichomycterid catfish genus Trichomycterus from the rio Ribeira de Iguape basin, southeastern Brazil, are described. Trichomycterus tupinamba differs from the other species of the Trichomycterinae in having the first pectoral-fin ray not prolonged as a filament, the caudal fin is truncate with attenuated edges, two paired supraorbital pores s6, eye oriented dorsally, a subterminal mouth, anal and urogenital openings mid-way between the pelvic-fin margin and anal-fin origin, a dark spot at the base of the nasal barbel, a longitudinal row of dark spots along the midline of the flank from the opercle to the caudal-fin base, a pectoral-girdle width of 13.1-17.7 % of standard length, and a caudal-peduncle depth of 8.7-10.3 % of standard length. Trichomycterus jacupiranga differs from all other species of the Trichomycterinae in having the first pectoralfin ray prolonged as a short filament, one fused supraorbital pore s6, a pelvic fin that covers the anal and urogenital openings, anal and urogenital openings that are closer to the anal-fin origin than to the pelvic-fin base, a truncated caudal fin with attenuated edges, and the following morphometric characteristics: head length 20.7-22.4 % standard length, preanal length 57.1-70.9 % standard length, pectoral girdle width 17.4-20.6 % standard length, trunk length 33.6-37.5 % standard length, pectoral-fin length 16.8-22.7 % standard length, dorsal-fin base length 12.8-14.1 % standard length, anal-fin base length 8.410.8 % standard length, head width 90.6-104.6 % head length, snout length 40.0-46.9 % head length, mouth width 27.0-37.3 % head length, and eye diameter 10.4-16.5 % head length. Distribution, ecological data and diagnostic features are presented for both new species.


Introduction
The large systematic diversity of the catfish genus Trichomycterus with 96 nominal species and many others still undescribed has been the focus of studies of several authors (Fernandez & Vari, 2000;Barbosa & Costa, 2003;Fernandez & Schaefer, 2003;de Pinna & Wosiacki, 2003;Wosiacki, 2004;Wosiacki & Garavello, 2004;and Bockmann & Sazima, 2004).However, this large assemblage has been hypothesized as a non natural group (de Pinna, 1989(de Pinna, , 1998)), a situation that can only be solved with a comprehensive analysis of all species of Trichomycteridae, in a phylogenetic paradigm.Despite the question of the monophyly of Trichomycterus, the generic name continues to be used widely for this assemblage of species and will be used in this paper as well.
Species of the Trichomycterinae previously recorded for the rio Ribeira de Iguape Basin are: Trichomycterus davisi (Haseman), Trichomycterus sp.(Wosiacki & Cury, 1990), T. iheringi (Eigenmann) (Bizerril, 1994), and Ituglanis proops (Miranda Ribeiro).One of us (OTO) recently conducted a comprehensive ichthyological inventory of this poorly-known basin which resulted in the discovery of one of the new species here described, from specimens collected in a tributary inside the conservation unit Parque Estadual de Jacupiranga, and the other new species from specimens collected in a distinct tributary close to this reserve.
The rio Ribeira de Iguape Basin (Southern Brazil, Fig. 1) lies within the Atlantic Rainforest, a heavily impacted habitat that has less than 5 % of its original forest intact.The knowledge of the diversity of freshwater fishes of this environment is important to the preservation, conservancy and management of this endangered ecoregion.

Materials and Methods
All measurements were taken point-to-point, with dial calipers, on the left side of the specimen.Caudal peduncle length was taken from the origin of the last anal-fin ray to the middle of the caudal-fin base; caudal-peduncle depth was measured vertically through the midpoint of the caudal peduncle.Other measurements follow Tchernavin (1944).Dorsal and anal-fin ray counts include all branched and unbranched rays that were visible in transmitted light.Osteological preparations were made according to a modified version of the method of Dingerkus & Uhler (1977).Trichomycterus jacupiranga not prepared for c&s.The Weberian complex and compound caudal centrum are not included in vertebral counts.Sensory canal pores are numbered according to Arratia (1998).Drawings were prepared with the aid of a stereomicroscope and a camera lucida.Institutional abbreviations follow Leviton et al. (1985) with the addition of MHNCI for Museu de História Natural "Capão da Imbuia", Curitiba, Brazil, and NUP for Núcleo de Pesquisas em Limnologia, Ictiologia e Aqüicultura, Maringá, Brazil.

Diagnosis.
Trichomycterus tupinamba differs from all other species of the subfamily Trichomycterinae by the following unique combination of characters: first pectoral-fin ray not prolonged as a filament (vs.prolonged), caudal fin truncate with attenuated edges (vs.rounded), two paired supraorbital pores s6 (vs.pores united as a single supraorbital pore s6), eye dorsally oriented (vs.dorsolaterally oriented), mouth subterminal (vs.terminal), anal and urogenital openings mid-way between pelvic-fin margin and anal-fin origin (vs.nearer to anal-fin origin), dark spot at base of nasal barbel (vs.dark spot absent), longitudinal row of dark spots along midline of flank from opercle to caudal-fin base (vs.longitudinal lateral series of spots absent), pectoral girdle width 13.1-17.7%SL, and caudal peduncle depth 8.7-10.3%SL.
Description.Morphometric data for holotype and paratypes are given in Table 1.Body elongate, roughly cylindrical close to head and gradually more compressed towards caudal fin.Dorsal and ventral profiles of trunk slightly convex.Dorsal and ventral profiles of caudal peduncle straight (Figs. 2 and 3).Integument thick, especially over base of dorsal and anal fins.Head wide and depressed, trapezoidal in dorsal view, slightly longer than wide or as long as wide (75.8-100.9% HL), width at posterior tip of opercle greater than width at nostril, anterior margin of snout slightly rounded (Fig. 4).Lateral region of eye slightly swollen by jaw muscles in large and small specimens.Dorsal and ventral profiles of head straight.Eye rounded, without well-defined rim, dorsally oriented, covered by thin skin in contact with center from surface of eyeball.Ocular structures readily visible on surface of skin, not deeply sunken.Orbital rim not free.Anterior nostril surrounded by fleshy flap of integument.Posterior nostril surrounded anteriorly by thin flap of integument.Anterior and posterior nostrils approximately same diameter as eye.Gill membranes thick, attached across isthmus only at anteriormost point, forming a small free fold across isthmus.Gill openings not constricted.Branchiostegal rays 7-8 (only 4 or 5 visible externally from below).Mouth subterminal, its corners laterally oriented.Lower lip with conspicuous lateral fleshy lobes, internal to origin of rictal barbel.Anterior margin of upper lip slightly rounded.Small papillae on external surface of upper lip and large papillae on inner surface of upper lip.Upper lip continuous with dorsal surface of head.Barbels long (nasal 35.5-54.2;maxillary 49.7-75.8;and rictal barbel length 41.7-60.6 % HL).Barbels with large base and narrowing gradually towards tip.Nasal barbel reaching to, or slightly beyond, posterior rim of eye; maxillary barbel reaching middle of interopercular patch of odontodes; rictal barbel reaching anterior most interopercular odontodes.Origin of nasal barbel on posterolateral portion of integument flap around anterior nostril.Interopercular patch of odontodes long, with 34-36 conical odontodes covered by thick integument (14-17 externally visible in alcohol specimens), external series smaller and straight, internal series larger, curved medially.Opercular patch of odontodes rounded, with 23-26 conical odontodes, anterior ones smaller and straight, posterior ones larger and curved medially.Sensory canals composed of complete supraorbital canal and incomplete infraorbital canal.Infraorbital anterior section pores i1 and i3, and posterior section pores i10 and i11.Supraorbital pores s1, s2 and s6.Two paired pores s6.
Pectoral-fin margin truncate, 8 rays, only first one unbranched, first the longest without a filamentous extension.Dorsal-fin margin semi circular, 12 rays (9 visible in intact specimens) rays, third through twelfth rays branched, third and fourth the longest.Anal fin slightly elongate in overall shape, smaller than dorsal fin, 9 rays (7 visible in intact speci-mens), third through ninth branched, third the longest, origin at vertical through seventh dorsal-fin ray.Pelvic-fin origin anterior to dorsal-fin origin, rounded margin, distant one half of its length from urogenital and anal openings, 5 rays, only first one unbranched, second and third rays longest.Caudalfin margin rounded with attenuated edges, distinctly deeper than remaining caudal region, 13 principal rays, dorsal and ventral external principal rays unbranched, branched rays splitting twice.Dorsal lobe procurrent rays 15-16.Ventral procurrent rays 10.Only first dorsal and ventral caudal-fin accessory rays visible.Anal and urogenital openings midway between pelvic-fin margin and anal-fin origin.
Color in alcohol.Refer to figures 2 to 4 for general view of color pattern in alcohol.Dorsal surfaces of head, trunk and caudal peduncle gray, darker over occipital region, becoming gradually lighter toward caudal peduncle.Dark stripe running between eye and anterior nostril.Thick skin surrounding opercular patch of odontodes dark.Narrow, dark midlateral stripe formed by closely spaced (sometimes continuous) black spots from opercle to vertical through anal-fin origin, and continuing posteriorly to caudal peduncle as series of irregularly spaced spots.Mid-lateral stripe darker in small specimens (28.2-58.8mm SL), gradually lighter in larger specimens (59.6-86.5 mm SL).Surface under dark lateral stripe pale, without pigmentation in small specimens (28.2-58.8mm SL), and with few scattered small spots near anal fin and ventral half of caudal peduncle.Dorsal surface of pectoral-fin base with few chromatophores, gradually scattered towards margin.Ventral surface of pectoral and pelvic fins unpigmented.Base of dorsal and anal fin with chromatophores, more scattered towards margin over rays.Dorsal fin darker than anal fin.Few chromatophores on caudal-fin rays, gradually more scattered towards margin.Base of nasal barbel dark, becoming gradually lighter towards the tip; maxillary barbel pale with few small dusky spots on dorsal surface.Rictal barbel unpigmented.Upper and lower lips unpigmented.Diagnosis.Trichomycterus jacupiranga differs from all other species of the subfamily Trichomycterinae by the following unique combination of characters: first pectoral-fin ray prolonged as short filament (vs.not prolonged), one supraorbital pore s6 fused (vs.two supraorbital pores s6 paired), pectoralfin rays 8 (vs.7 or 6), pelvic fin covering anal and urogenital opening (vs.not covering), anal and urogenital opening closer to anal-fin origin than to pelvic-fin base (vs.midway between anal-fin origin and pelvic-fin base), caudal fin truncated with attenuated edges (vs.rounded or truncated without attenuated edges), and the following morphometric characteristics: head length 20.7-22.4 % SL, and head width 90.6-104.6 % HL.
Description.Morphometric data for holotype and paratypes are given in Table 1.Body elongate, roughly cylindrical just posterior of head and gradually more compressed towards caudal fin.Profile of trunk straight dorsally and slightly convex ventrally.Dorsal and ventral profiles of caudal peduncle straight (Fig. 5).Integument thick, especially over base of dorsal and anal fins.
Head wide and depressed, trapezoidal in dorsal view, as long as wide (90.6-104.6 % HL), width at posterior tip of opercle greater than width at nostril, anterior margin of snout rounded (Fig. 6).Lateral region of eye slightly swollen by jaw muscles in large and small specimens.Dorsal profile of head straight in lateral view, ventral profile convex.Eye rounded, without well-defined rim, dorsally oriented, covered by thin skin in contact with center from surface of eyeball.Ocular structures readily visible on surface of skin, not deeply sunken.Pectoral-fin margin truncate, 8 rays, only first one unbranched; first ray longest with a short filamentous extension.Dorsal-fin margin semicircular when expanded, 9 rays, third through ninth branched, fourth longest.Anal fin slightly elongate in overall shape, slightly smaller than dorsal fin, 7 rays, third through seventh branched, fourth longest, origin at vertical through last dorsal-fin ray.Pelvic-fin origin anterior to dorsal-fin origin, rounded margin, covering urogenital Color in alcohol.Refer to figures 5 and 6 for general view of color pattern in alcohol.Color pattern similar in all examined (33.5-57.4mm SL) specimens.Dorsal surface of trunk uniform gray, gradually lighter laterally.Body with narrow, poorly defined mid-lateral stripe from head to caudal peduncle.Dorsal surface of head gray, darker over neurocranium.Skin covering jaw musculature lighter than surrounding area and with few chromatophores.Nasal barbel with few chromatophores on dorsal surface.Maxillary and rictal barbels unpigmented.Ventral surfaces of head, trunk and caudal peduncle unpigmented.Pectoral fin with few chromatophores restricted to dorsal surface of base of first ray.Pelvic and anal fins unpigmented.Dorsal fin with few chromatophores over base of rays.Caudal fin hyaline.
Distribution.Known only from the type locality.
Etymology.The species name, jacupiranga, refers to the type locality, Parque Estadual de Jacupiranga, município de Cajati, São Paulo, Brazil.Jacupiranga is also the indigenous Tupylanguage name for a species of bird native to the region (Penelope obscura -Cracidae), commonly known as the dusky-legged guan, and comes from yaku (a bird) and piranga (red).Treated here as a noun in apposition.

Remarks.
The two new species, Trichomycterus tupinamba and T. jacupiranga, were included in the genus Trichomycterus for reasons similar to those discussed in Fernandez & Vari (2000), Bockmann et al. (2004), Wosiacki (2004), and Wosiacki (2005).Both species are recorded from rio Ribeira de Iguape basin, south and southeastern Brazil, where six species of trichomycterids were previously recognized: Trichomycterus davisi from the headwaters (Wosiacki & Cury, 1992)  Trichomycterus tupinamba is distinguished from T. plumbeus and T. guaraquessaba by having a color pattern composed of a narrow dark mid-lateral stripe from opercle to vertical through anal-fin origin, absent in the later species.Trichomycterus tupinamba and T. paolence are similar to each other in having a dark mid-lateral stripe from the opercle to a vertical line through the anal-fin origin.However, T. paolence has a dark stripe "along the side of the back and a stripe along the edge of the belly" (Eigenmann, 1918), the latter of which is absent in T. tupinamba.Trichomycterus tupinamba has eight pectoral-fin rays, the first is the longest, without a filamentous extension, which helps differentiate it from T. triguttatus (Eigenmann) and the holotype of T. paolence both of which have with six pectoral-fin rays and the first ray prolonged as a filament.
Trichomycterus jacupiranga has one s6 supraorbital pore fused, distinct from T. concolor and T. immaculatus, which have two paired s6 supraorbital pores.Trichomycterus jacupiranga shares with T. nigricans one s6 supraorbital pore and the first pectoral-fin ray prolonged as a short filament (Arratia, 1998), and is distinguished from this species by having eight pectoral-fin rays vs. nine rays (Arratia, 1998) in T. nigricans.Trichomycterus jacupiranga shares with T. triguttatus the first pectoral-fin ray prolonged as a long filament and is distinguished from that species by the presences of only one supraorbital s6 pore vs. two paired supraorbital s6 pores.
Orbital rim not free.Anterior nostril surrounded by fleshy flap of integument.Posterior nostril surrounded anteriorly by thin flap of integument.Anterior and posterior nostrils approximately same diameter as eye.Gill membranes thick, attached across isthmus only at anterior most point.Gill openings not constricted.Branchiostegal rays 3 or 4 externally visible from below.Mouth subterminal, its corners laterally oriented.Lower lip with conspicuous lateral fleshy lobes internal to origin of rictal barbel.Anterior margin of upper lip rounded.Small papillae on external surface of upper lip and large papillae on inner surface of upper lip.Upper lip continuous with dorsal surface of head.Barbels long (nasal 33.3-60.0;maxillary 63.5-70.0;and rictal barbel length 40.0-55.0% HL).Barbels with large base and narrowing gradually towards tip.Nasal barbel reaching to midway between posterior rim of eye and base of anterior opercular odontodes; maxillary barbel reaching tip of posterior opercular odontodes; rictal barbel reaching base of posteriormost interopercular odontodes.Origin of nasal barbel on posterolateral portion of integument flap around anterior nostril.Interopercular patch of odontodes long, 33-38 conical odontodes covered by thick integument, external series smaller and straight and internal series larger, curved medially.Opercular patch of odontodes rounded, with 20-23 conical odontodes, anterior ones smaller and straight, posterior ones larger and curved medially.Sensory canals composed of complete supraorbital canal and incomplete infraorbital canal.Infraorbital anterior section pores i1 and i3, and posterior section pores i10 and i11.Supraorbital pores s1, s2 and a single s6 pore at interorbital space.