Listrura picinguabae, Leandro Villa-Verde & Wilson J. E. M. Costa, 2006

Leandro Villa-Verde & Wilson J. E. M. Costa, 2006, A new glanapterygine catfish of the genus Listrura (Siluriformes: Trichomycteridae) from the southeastern Brazilian coastal plains., Zootaxa 1142, pp. 43-50 : 44-49

Listrura picinguabae new species

(Figs. 1-3)

Listrura nematopteryx de Pinna and Wosiacki (2003).

Holotype. UFRJ 6111, 48.6 mm SL; Brazil: Estado de Sào Paulo: Município de Ubatuba, serra do Mar, Picinguaba, small stream tributary to rio da Fazenda, on small road near Km 11 of the road BR-101, Parque Estadual da Serra do Mar, about 23°20’S 44°45’W; W. J. E. M. Costa, B. Costa & L. Villa-Verde, 19 September 2005.

Paratypes. All from streams close to rio da Fazenda, Picinguaba, São Paulo, Brazil: MCP 38921, 2 ex., 42.5-31.8 mm SL; W. J. E. M. Costa & M. I. Landim, October, 1996. UFRJ 5948, 1 ex., 35.5 mm SL; R. Sachsse & S. Potsch, 23 August 1992. UFRJ 5949, 2 ex., 24.3-32.3 mm SL; L. N. Weber, August 1996. UFRJ 5950, 15 ex., 29.4-45.3 mm SL; W. J. E. M. Costa & M. I. Landim, October, 1996. UFRJ 5951, 4 ex., 31.3-35.5 mm SL (all c&s); no data on collectors and date. UFRJ 5991, 2 ex., 26.3-31.9 mm SL, L. N. Weber, 15 October 1994. UFRJ 6138, 5 ex., 36.0-50.2 mm SL (all c&s), no data on collectors and date.

Diagnosis

Listrura picinguabae is similar to L. nematopteryx , and distinguished from all other trichomycterids in possessing a single long pectoral-fin ray. It differs from L. nematopteryx in having the anal-fin origin anterior to dorsal-fin origin (dorsal-fin origin on vertical between base of 3rd and 4th anal-fin rays) to anal-fin origin slightly posterior to dorsal-fin origin, anal-fin origin on vertical through base of 2nd dorsal-fin ray (vs. anal-fin origin always posterior to dorsal-fin origin, on vertical between 3rd and 5th dorsal-fin rays), dorsal-fin origin at vertical between centra of 34th and 37th vertebrae (vs. between 31st and 34th), 8-10 anal-fin rays (vs. 7-8), 6-8 opercular odontodes (vs. 4-6), 7-10 interopercular odontodes (vs. 5-7), and lateral process of urohyal reaching posterior region of anterior ceratohyal (vs. reaching posterior region of posterior ceratohyal) (Fig. 4).

Description

Morphometric data given in Table 1. Body elongate, subcylindrical on anterior portion of trunk, to strongly compressed on caudal peduncle. Dorsal and ventral profiles straight or slightly curved on anterior portion of body. Skin papillae minute.

Head depressed, trapezoidal with square anterior portion in dorsal view (Fig. 3B). Snout blunt. Mouth subterminal and narrow. Teeth conical, tips pointed and curved. Jaw teeth distributed in two rows. Premaxillary teeth 17-26; dentary teeth 13-15. Eyes anteriorly located on head, nearer snout tip than opercular patch of odontodes. Tip of nasal barbel reaching between posterior margin of interopercular patch of odontodes and posterior margin of opercular patch of odontodes. Tip of maxillary barbel reaching beyond posterior margin of interopercular patch of odontodes. Tip of rictal barbel reaching between middle of interopercular patch of odontodes and posterior margin of opercular patch of odontodes. Branchiostegal rays 6. Interopercular odontodes 7-10, opercular odontodes 6-8; odontodes conical, tips pointed and slightly curved.

Dorsal and anal fins triangular. Dorsal-fin origin at vertical between centra of 34th and 37th vertebrae. Anal-fin origin anterior to dorsal-fin origin (dorsal-fin origin on vertical between base of 3rd and 4th anal-fin rays) to anal-fin origin slightly posterior to dorsal-fin origin (anal-fin origin on vertical between base of 3rd and 4th dorsal-fin rays); dorsal-fin origin between centra of 34th and 36th vertebrae. Caudal-fin rounded. Pectoral-fin with single long ray. Pelvic fin and pelvic girdle absent. Dorsal-fin rays 7, all unbranched; analfin rays 8-10, all unbranched; principal caudal-fin rays 11-13, dorsal procurrent rays 26-35, ventral procurrent rays 25-30. Pleural ribs 2-3. Total vertebrae 51-55. Caudal skeleton compact, parahypural fused to hypurals 1-2; hypurals 1-2 almost completely fused to hypurals 3-5. Uroneural and haemal spine sometimes fused to caudal complex. Branchial membranes attached only at anteriormost point of isthmus. Anterior nostril just anterior to nasal barbel. Posterior nostril located on anterior half of distance between anterior nostril and eye.

Lateral-sensory system extremely reduced. Supraorbital and infraorbital canals absent. Preopercular canal with one pore, at vertical through anterior margin of opercular patch of odontodes. Pterotic branch of post-otic canal, with one pore at vertical just posterior to opercular patch of odontodes. Lateral line of body short, with two pores; first pore largest, at vertical just posterior to pectoral-fin base, second pore just posterior to second pore (see Fig. 3).

Coloration in alcohol: Side of body light brown, with horizontal midlateral brown line.

Lateral surface of caudal peduncle with two oblique brown lines posteriorly turned, above and below lateral line, and small brown spots on posterior portion of caudal peduncle extending over base of dorsal procurrent caudal-fin rays. Dorsal surface of trunk with two brown lines, and three brown longitudinal lines on center of dorsum, posteriorly converging to form single stripe along dorsal midline. Ventral surface almost white. Dorsal portion of head with large, trapezoidal brown blotch narrower anteriorly, between nape and vertical through eyes. Barbels and fins nearly white.

Distribution

Known only from the type locality region, in small tributaries to rio da Fazenda, São Paulo State, southeastern Brazil.

Habitat notes

The new species was collected in narrow (about 50 cm wide) and shallow (about 20 cm deep) streams in a dense tropical forest (Mata Atlântica). Individuals were found buried in the litter bottom. No other fishes were observed, but tadpoles (unidentified) were present.

Etymology

The name picinguabae is in allusion to the name of type locality of the new species, Picinguaba, southeastern Brazil.

Discussion

Two species of Listrura , L. camposi and L. boticario , are known only from their holotypes. The lack of osteological information for these species impedes a complete analysis of phylogenetic relationships within the genus. However, it is possible that Listrura nematopteryx and L. picinguabae comprise a monophyletic assemblage, given the fact that the pectoral fin of these species consists of a single ray and the ray is in the form of a long filament. This condition is not present in any other trichomycterids thus far described.

The lateral process of the urohyal is longer in L. nematopteryx than in L. picinguabae (Fig. 3). The apomorphic vomer bottle-shaped identified by de Pinna (1988) as a possible synapomorphy for Listrura and corroborated by Landim and Costa (2002), also occurs in L. picinguabae (Fig. 5). However, the vomer of L. picinguabae bears a short pointed posterior process, which is forked is some specimens.