Trichomycterus caudofasciatus, Alencar, Aline R & Costa, Wilson J. E. M., 2004

Alencar, Aline R & Costa, Wilson J. E. M., 2004, Description of two new species of the catfish genus Trichomycterus from southeastern Brazil (Siluriformes: Trichomycteridae), Zootaxa 744, pp. 1-8 : 5-8

Trichomycterus caudofasciatus new species

( Fig. 2 )

Holotype. UFRJ 6002, 48.5 mm SL; Brazil: Estado de Minas Gerais: Município de Alto Caparaó, Rio Caparaó, Rio Itabapoana basin, Alto Caparaó, 20°25’53.9”S 41°51’56.8”W, altitude 1047 m; W. J. E. M. Costa, B. B. Costa and C. P. Bove, 23 December 2002.

Paratypes. Brazil: Estado de Minas Gerais: Rio Itabapoana basin: MCP 35030, 2 ex., 39.4–40.0 mm SL; UFRJ 5655, 10 ex., 36.2–41,9 mm SL; UFRJ 5656, 5 ex. (c&s), 34.5– 48.8 mm SL; collected with holotype. UFRJ 5657, 10 ex., 29.6–42.5 mm SL; Cachoeira do Chiador, Rio São Domingos, about 17 km N from Espera Feliz, 20°33’24.8”S 41°51’26.9”W, altitude 957 m; W. J. E. M. Costa, B. B. Costa and C. P. Bove, 23 December 2002. UFRJ 4070, 5 ex., 26.7–52.9 mm SL; waterfall in Rio São Domingos, about 3 km from Paraíso, near Espera Feliz; F. Pupo, 2 February.1997.

Diagnosis: Similar to T. alternatus , T. longibarbatus and T. pantherinus and distinguished from all other species of the genus by the combination of the following features: 7–8 pectoral­fin rays, long filamentous first pectoral­fin ray (about 50–70 % pectoral­fin length), 10–20 opercular odontodes, 30–52 interopercular odontodes, opercular patch of odontodes wide, and 6–7 branchiostegal rays. It is easily distinguished from T. alternatus , T. longibarbatus and T. pantherinus by having a single median last supraorbital pore (vs. paired pore). Distinguished from all other species of Trichomycterus from the Brazilian Shield river basins by a unique color pattern, consisting of four gray bars on the caudal fin.

Description: Morphometric data for holotype and paratypes given in Table 2. Body moderately deep, subcylindrical on anterior portion, compressed on caudal peduncle. Dorsal profile gently convex between snout and end of dorsal­fin base, straight to slightly convex on caudal peduncle. Ventral profile straight to slightly convex between lower jaw and end of anal­fin base, straight on caudal peduncle. Greatest body depth in vertical immediately in front of pelvic­fin origin. Skin papillae minute.

TABLE 2. Morphometric data of Trichomycterus caudofasciatus . H: holotype.

H Paratypes (UFRJ 5655, 5657)

Standard length (mm) 48.8 34.4 37.3 44.1 40.9 41.8 41.9 53.8 51.4 42.5 41.1 37.2 35.3

Percents of standard length

Body depth 14.8 14.0 14.9 15.5 15.8 13.8 14.8 13.7 14.0 14.6 15.4 13.9 13.7

Caudal peduncle depth 10.4 9.4 9.8 10.3 10.4 9.4 10.9 8.9 10.4 9.8 10.2 9.9 8.7

Body width 9.4 7.8 9.9 9.9 9.7 9.0 10.6 8.6 8.7 9.1 10.2 7.9 8.3

Caudal peduncle width 1.9 2.1 2.2 2.3 2.5 2.5 2.5 2.1 2.3 2.0 2.0 1.8 2.3

Dorsal­fin base length 9.5 10.9 9.2 10.1 10.3 9.2 11.3 10.3 10.9 13.1 11.6 11.6 11.6

Anal­fin base length 6.8 8.3 8.8 7.6 7.7 8.0 7.5 8.8 9.0 7.7 7.2 7.6 7.7

Pelvic­fin length 10.1 10.2 10.3 10.1 10.5 9.7 10.7 9.8 10.1 10.2 11.1 11.6 10.4

Distance between pelvic­fin 1.9 1.6 1.3 1.9 1.7 1.6 1.6 1.5 1.8 1.8 1.6 1.4 1.9 bases

Pectoral­fin length 15.3 16.4 17.1 14.7 14.5 14.5 14.3 15.1 14.2 14.0 17.3 14.9 17.0

Predorsal length 60.0 58.6 60.5 58.2 56.6 58.6 57.7 58.7 57.5 59.2 59.3 57.5 58.1

Prepelvic length 53.1 53.6 54.3 54.7 52.8 54.2 52.0 53.8 52.5 54.6 54.6 53.2 54.7

Head length 21.1 21.0 22.0 21.3 22.7 21.3 20.3 20.4 20.2 22.4 20.7 20.9 22.4

Percents of head

Dorsal and anal­fins subtriangular. Dorsal­fin origin at vertical through centrum of 17th vertebra. Anal­fin origin at vertical through base of 8th or 9th dorsal­fin ray and through centrum of 21st or 22nd vertebra. Pectoral fin about triangular, lateral and posterior edges slightly convex. First pectoral­fin ray terminating in long filament, about 50 % of pectoral­fin length. Pelvic­fin shorter than anal­fin, covering urogenital pore, tip not reaching anal fin, in vertical through base of 1st branched dorsal­fin ray; pelvic­fin bases separated by interspace; pelvic­fin origin in vertical through centrum of 14th or 15th vertebra. Urogenital papilla spherical, in vertical through anterior third of dorsal­fin base. Caudal fin truncate. Dorsal­fin rays 10–11; anal­fin rays 9; pectoral­fin rays 8; pelvic­fin rays 5; caudal­fin principal rays 13, dorsal procurrent rays 16–18, ventral procurrent rays 12– 14. Total vertebrae 35–37; pleural ribs 9–11. Two upper hypurals, sometimes ankylosed; single lower hypural plate and parhypural completely fused. Upper hypural plates separated, both approximately equal in width; single lower hypural plate and parahypural completely fused.

Head subtriangular in dorsal view. Snout blunt. Mouth subventral. Maxilla slightly longer than premaxilla. Teeth cylindrical, tip slightly pointed. Eye at middle of head. Nasal, maxillary and rictal barbels well developed. Tip of nasal barbel reaching midlength between eye and anterior edge of opercular patch of odontodes. Tip of maxillary barbel reaching anterior margin of opercular patch of odontodes. Tip of rictal barbel reaching anterior margin of opercular patch of odontodes. Seven branchiostegal rays. Interopercular odontodes 30–40; opercular patch of odontodes wide, with 12–16 odontodes; odontodes conical, opercular odontodes wider than interopercular odontodes; opercular odontodes arranged vertically.

Supraorbital canal continuous, with three pores; first pore in transverse line through anterior nostril, second in transverse line just posterior to posterior nostril, single median third supraorbital pore in transverse line just posterior to orbit. Infraorbital divided into two sections, each with two pores, anterior section of infraorbital canal present; first infraorbital pore in transverse line through anterior nostril, second in transverse line just anterior to posterior nostril, third and fourth posterior to orbit. Preopercular canal with one pore, in vertical through anterior margin of opercular patch of odontodes. Lateral line of body short, with three pores, posteriormost pore in vertical just posterior to pectoral­fin base.

Coloration: Side of body light purplish brown with row of rectangular, or sometimes rounded, dark brown spots on lateral midline, and similar rows of paler spots above and below lateral midline; golden spots on posterior half of flank between midline spots; venter white. Head dark brown on dorsal, white on ventral surface; suborbital region light brown, preopercular region dark brown; opercular and interopercular patches of odontodes light yellow; nasal barbel dark gray, maxillary and rictal barbels light gray. Iris light yellow. Dorsal­fin yellowish hyaline with small dark brown spots on anterior and basal portions. Caudal­fin yellowish hyaline with four faint gray bars. Anal and pelvic­fins pale yellow. Pectoral­fin pale yellow, basal portion dark gray.

Distribution: Upper Rio Itabapoana basin, Serra do Caparaó, southeastern Brazil. Habitat notes: This species was found in two localities: Rio São Domingos, the type locality, with turbid water, and in Rio Caparaó, with clear water. In both localities it was found in shallow waters (40–100 cm deep), sometimes swimming in daylight, but most specimens were collected under marginal vegetation or under vegetal debris on the bottom.

Etymology: From the Latin cauda (tail) and fasciatus (with bars), referring to the caudal­fin color pattern of the new species.

Figures

FIGURE 2. Trichomycterus caudofasciatus, UFRJ 6002, live holotype, 48.5 mm SL; Brazil: Minas Gerais: Alto Caparaó (Photo by W. J. E. M. Costa).