Trichomycterus jacupiranga, Wosiacki & Oyakawa, 2005

Wosiacki, Wolmar Benjamin & Oyakawa, Osvaldo Takeshi, 2005, Two new species of the catfish genus Trichomycterus (Siluriformes: Trichomycteridae) from the rio Ribeira de Iguape Basin, Southeastern Brazil, Neotropical Ichthyology 3 (4), pp. 465-472 : 469-471

Trichomycterus jacupiranga , new species Figs. 5-6

Holotype. Brazil, São Paulo: MZUSP 67818 , 57.4 mm SL, rio do Queimado, Parque Estadual de Jacupiranga, Cajati, O. T. Oyakawa, A. Akama, J. C. Nolasco, A. C. Paixão & R. T. Nasakumi , 9 Mar 2001.

Paratypes. MZUSP 84095 , 1 , 33.5 mm SL ; MZUSP 67819 , 1 , 47.6 mm SL ; MZUSP 67820 , 1 , 50.0 mm SL ; MZUSP 67821 , 1 , 51.0 mm SL ; MZUSP 67822 , 1 . 48.3 mm SL; all collected with holotype .

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. 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.

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 and anal openings, 5 rays, only first one unbranched, second and third longest. Caudal fin truncated with attenuated edges, distinctly deeper than remaining caudal region, 13 principal rays, dorsal and ventral external principal rays unbranched, branched rays splitting three times. Only first dorsal and ventral caudal-fin accessory rays visible. Anal and urogenital openings closer to anal-fin origin than to pelvic-fin base.

Color in alcohol. Refer to figures 5 and 6 for general view of color pattern in alcohol. Color pattern similar in all examined (33.5-57.4 mm 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.

Ecological notes. Rio do Queimado, in the stretches where T. jacupiranga was collected, is a medium-sized, clearwater river with strong to moderate current flowing mainly over sand beds, intercalated with some rocky portions. Even though the type locality is inside the Conservation Unit Parque Estadual de Jacupiranga, the riparian vegetation is highly degraded and in certain areas there are many banana plantations. The microhabitat occupied by Trichomycterus jacupiranga is in sand beds within which they bury themselves; a behavior also seen in T. alternatus (Eigenmann) (pers. obs.). The following species of fishes occur syntopically with Trichomycterus jacupiranga : Astyanax sp. , Characidium pterostictum Gomes , Hisonotus gibbosus (Miranda-Ribeiro) , Hypostomus tapijara Oyakawa,Akama & Zanata , Kronichthys lacerta (Nichols) , Parotocinclus maculicauda (Steindachner) , Pseudotothyris obtusa (Miranda-Ribeiro) , Schizolecis guntheri (Miranda-Ribeiro) , and T. zonatus .

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), Microcambeva ribeirae Costa, Lima & Bizerril, Listrura camposi (Miranda-Ribeiro) , Ituglanis proops , Trichomycterus iheringi , and T. brasiliensis (Lütken) based in Eigenmann (1918; as T. brasiliensis tristis Lütken ).

No autapomorphies were observed for T. tupinamba or T. jacupiranga , and their diagnoses are possible by combinations of characters. The absence of large or small spots or stripes on dorsum of head and trunk distinguishes each species from a large assemblage of species which possess these characteristics and are distributed in south and southeastern Brazil, including: T. albinotatus Costa, T. alternatus (Eigenmann) , T. auroguttatus Costa, T. bahianus Costa, T. brasiliensis , T. candidus (Miranda-Ribeiro) , T. castroi de Pinna , T. caudofasciatus Alencar & Costa, T. davisi , T. diabolus Bockmann et al. , T. giganteus Lima & Costa, T. goeldii Boulenger , T. itacambirussu Triques & Vono , T. itatiayae Miranda-Ribeiro , T. jequitinhonhae Triques & Vono , T. landinga Triques & Vono , T. longibarbatus Costa, T. mboycy Wosiacki & Garavello , T. maracaya Bockma & Sazima , T. mimonha Costa, T. mirissumba Costa, T. naipi Wosiacki & Garavello , T. pantherinus Alencar & Costa, T. potschi Barbosa & Costa, T. taroba Wosiacki & Garavello , T. reinhardti (Eigenmann) , T. stawiarski (Miranda-Ribeiro) , T. variegatus Costa, T. vermiculatus (Eigenmann) , and T. zonatus . Trichomycterus tupinamba and T. jacupiranga are distinguished from T. papilliferus Wosiacki & Garavello which has extremely short maxillary (18-31% HL) and rictal barbels (12- 30% HL), and conspicuous papillae in the ventral surface of head, all of which were proposed as autapomorphies by Wosiacki & Garavello (2004).

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.

Comparative material. See Wosiacki (2004).

Figures

Fig. 5. Trichomycterus jacupiranga, holotype, MZUSP 67818, 57.4 mm.

Fig. 6. Trichomycterus jacupiranga, holotype, MZUSP 67818, 57.4 mm, dorsal view of the head. Scale bar = 5 mm.