Trichomycterus payaya, Sarmento-Soares & Zanata & Martins-Pinheiro, 2011

Sarmento-Soares, Luisa M., Zanata, Angela M. & Martins-Pinheiro, Ronaldo F., 2011, Trichomycterus payaya, new catfish from headwaters of rio (Siluriformes: Trichomycteridae) Itapicuru, Bahia, Brazil, Neotropical Ichthyology 9 (2), pp. 261-271 : 262-266

Trichomycterus payaya , new species

Figs. 1-7

Holotype. MNRJ 36665 , 37.4 mm SL, Brazil, Bahia, Miguel Calmon, riacho Olhos d’água on road BA-131, tributary to rio Itapicurumirim , rio Itapicuru drainage, between Miguel Calmon and Jacobina, 40º36’21.9”S 11º20’19.5”W, 505 m a.s.l., 12 Jun 2005, A. Zanata, P. Camelier, J. O. Birindelli, O. T. Oyakawa, M. P. Geraldes & P. Moura.

Paratypes. ANSP 190965 , 2 alc., 27.2-27.8 mm SL; MBML 2559, 1 alc., 34.0 mm SL; MBML 2560, 1 c&s, 30.1 mm SL ; MNRJ 36666 , 2 alc., 28.6-31.6 mm SL ; MZUSP 88164 , 8 alc., 25.5-35.6 mm SL ; UFBA 5286 , 2 alc. 29.2-31.4 mm SL and 1 c&s, 31.1 mm SL, collected with the holotype . UFBA 5284 , 1 alc., 36.5 mm SL and 1 c&s, 24.1 mm SL, Brazil, Bahia, Jacobina, stream between BR-342 and Itaitu, tributary of rio Itapicuru-mirim , rio Itapicuru drainage, 40º28’11.2”S 11º19’41.1”W, 547 masl, 13 Jun 2005, A. Zanata, P. Camelier, J. O. Birindelli, O . T. Oyakawa, M. P. Geraldes and P. Moura .

Diagnosis. Trichomycterus payaya is distinguished from all congeners by a unique combination of features: head rounded anteriorly in dorsal view and slightly depressed in lateral view; supraorbital pores s6 paired, opening laterally on supraorbital sensory branch, not emerging from an epiphyseal branch; lateral process of urohyal distally sharp, with pointed tip; reduced number of pleural ribs (5-6 ribs); and interopercular patch of odontodes longer than deep, with 21-26 odontodes. Trichomycterus payaya can be further distinguished from all congeners inhabiting the Brazilian coastal rivers located north of rio Paraíba do Sul ( T. alternatus , T. bahianus , T. brunoi , T. caudofasciatus , T. itacambirussu , T. jequitinhonhae , T. landinga , T. longibarbatus , T. pantherinus , T. pradensis ) by having the dorsal fin positioned somewhat posteriorly, the distance from the dorsal-fin origin to the base of the middle caudal-fin rays 1.9-2.2 in predorsal distance (vs. 1.4-1.8 in predorsal distance).

The new species differs further from congeners of northeastern Brazilian drainages ( T. bahianus , T. itacambirussu , T. jequitinhonhae , T. landinga , T. pradensis ) by having a large opercular odontode patch with 16-19 odontodes (vs. small odontode patch with 8-13 odontodes). It differs further from T. bahianus , T. itacambirussu , and T. jequitinhonhae by having body coloration somewhat homogeneous, with minute spots distributed throughout (vs. presence of rounded dark brown or gray spots sometimes arranged into series along body), from T. landinga by having dorsal and ventral flanks similarly colored (vs. dorsal flank finely dotted and ventral flank with dark dots scarce), and from T. pradensis and T. itacambirussu by having six branched pectoral-fin rays (vs. eight or nine). Trichomycterus payaya can be also distinguished from its congeners of the rio São Francisco drainage ( T. brasiliensis , T. concolor , T. macrotrichopterus , T. novalimensis , T. reinhardti , T. rubiginosus , T. trefauti , T. variegatus ) by having a narrower caudal peduncle (7.5-9.6% vs. 10.5-13% of SL) and longer nasal barbel (14.2-15.9% vs. 8.4-12.9% of SL). See discussion for details on other distinguishing features.

Description. Morphometric and meristic data presented in Table 1. Body slim, trunk compressed, caudal peduncle laterally compressed. Dorsal profile of body gradually ascending from tip of snout to anterior portion of trunk, approximately straight from that point to base of dorsal fin, descending along dorsalfin base and straight on caudal peduncle until caudal fin. Ventral profile of head gently sloped. Ventral profile of body almost straight to shallowly convex.

Head rounded anteriorly in dorsal view, small, and slightly depressed. Eyes small, orbital margin not free; thin skin covering eye. Anterior nostril surrounded by fleshy, tubeshaped flap of integument. Posterior nostril surrounded anteriorly by raised fleshy flap and located slightly closer to anterior nostrils than to eye. Mouth subterminal; lower lip contoured by fleshy lobe medial to origin of rictal barbels; upper lip with fleshy fold limited to base of maxillary barbel. Nasal barbel originating on lateral portion of integumentary flap around anterior nostril; tip of barbel reaching opercular odontode patch. Maxillary barbel reaching pectoral-fin origin. Rictal barbel extending to interopercular odontode patch. Autopalatine large, posteriorly expanded with wide lateral projection. Jaws subequal; premaxilla and dentary almost straight with two or rarely three rows of conical teeth. Premaxilla narrow, transversely elongated, meeting its counterpart medially. Maxilla well developed and curved. Branchial membranes thick, united to isthmus only anteriorly.

Mesethmoid long, thin, with anterior border slightly concave, premaxillary held underneath narrow anterior cornua through synchondral articulation. Lateral ethmoid projected laterally. Anterior cranial fontanel elliptical, bounded by frontals (Fig. 2). Epiphyseal bar incompletely sutured medially. Posterior cranial fontanel long and narrow, slightly expanded laterally along sutures between frontals and parietosupraoccipital. Lacrimal somewhat straight. Fronto-lachrymal tendon-bone long, rod-like, without lateral projection.Anterior portion of sphenotic-prootic-pterosphenoid projected laterally, bearing infraorbital sensory canal openings. Pterotic laterally projected. Posttemporo-supracleithrum short, in posterior corner of head, bearing postotic laterosensory branch. Vomer arrow-shaped, narrow, with long paired posterior processes. Parasphenoid with long posterior process, reaching middle of basioccipital-exoccipital ( Fig. 3 ).

Anterior portion of Weberian complex fused to basioccipital-exoccipital. Suspensorium with robust hyomandibula, projected anteriorly as membranous outgrowth. Laminar projection of hyomandibula anteriorly sutured to quadrate only, not contacting metapterygoid. Metapterygoid short, laminar, almost rectangular, joined to quadrate via anterior cartilage block only. Quadrate elongate, with broad base and anterior laminar projection contacting both hyomandibula and metapterygoid. Quadrate and hyomandibula contacted also through their broad bases and cartilaginous joint. Short preopercle sutured to ventral margins of both quadrate and hyomandibula. Opercular patch of odontodes large and roundish. Opercle with 16-19* elongate odontodes, posterior ones longest. Interopercular patch of odontodes longer than deep, with short anterior process. Interopercle with 21-26* odontodes arranged into two or three irregular rows ( Fig. 4 ).

Hyoid arch with large ventral hypohyal, elongate anterior ceratohyal and somewhat triangular posterior ceratohyal with markedly concave posterior face and with articulatory surface for interopercle and ligamentous connection to suspensorium. Seven branchiostegal rays articulated with hyoid arch: three with anterior ceratohyal, one with interceratohyal cartilage between bones, and three with posterior ceratohyal. Brachiostegal rays 4-6, distally expanded and notched. Dorsal hypohyal and interhyal absent. Urohyal wide, bearing conspicuous foramen. Anterior head of urohyal expanded, lateral processes elongated, laminar, sharpened distally to pointed tip. Posterior process of urohyal moderately short and sharpened ( Fig. 5 ).

Basibranchial 1 absent; basibranchial 2 and 3 with cartilaginous anterior and posterior tips, connected to each other, forming osseous rod. Anterior cartilaginous tip of basibranchial axis reaching close to hypobranchial 1; posterior osseous tips nearly in contact with contralateral hypobranchial 3. Cartilage between basibranchial 2 and 3 bordered laterally by cartilaginous head of hypobranchial 2. Basibranchial 4 hexagonal and completely cartilaginous, bordered anteriorly by cartilaginous head of ceratobranchial 4 and posteriorly by cartilaginous head of ceratobranchial 5. Hypobranchial 1 osseous, rod like, with cartilage on its proximal and distal tips. Hypobranchial 2 elongate, cartilaginous, almost trapezoid, with osseous anterodistal process. Hypobranchial 3 approximately trapezoidal, mostly cartilaginous and positioned close to its counterpart. Hypobranchial 4 absent. Five ceratobranchials, mostly ossified, extremities cartilaginous. First ceratobranchial short, supporting diminutive rakers. Second and third ceratobranchials each with shallow cavity along posterior margin and mesial laminar extension. Fourth ceratobranchial with diminutive concavity. Fifth ceratobranchial with short proximal tip, slightly expanded posteromedially to support lower pharyngeal tooth plate. Tooth plate with fine conical teeth arranged in two rows, with about seven teeth in mesial row. Five epibranchials, first three-rod like, short, ossified, except for cartilaginous extremities. Posterior margin of epibranchial 1 with elongate anterior process. Epibranchial 2 with vestigial process on its anterior margin. Epibranchial 3 with elongate posterior uncinate process. Epibranchial 4 broad, somewhat rectangular, without processes. Epibranchial 5 very small, completely cartilaginous, placed between posterior cartilaginous tips of epibranchial 4 and ceratobranchial 4. Pharyngobranchials 1 and 2 absent. Pharyngobranchial 3 elongate, ossified, rod-like, with Fig. 2. Neurocranium and Weberian apparatus of Trichomycterus payaya, UFBA 5286, paratype, 31.4 mm SL. Dorsal view. Abbreviations: af, anterior fontanel; ao, lacrimal; ap, autopalatine; ep, epioccipital; fl, frontolacrimal tendon bone; fr, frontal; i10, i11, infraorbital sensory pores 10 to 11; le, lateral ethmoid; me, mesethmoid; mx, maxilla; pf, posterior fontanel; pm, premaxilla; ps, posttemporo supracleitrum; pt, pterotic; p1, p2, postotic sensory pores 1 to 2; so, parieto-supraoccipital; sp, sphenotic; s1, s3, s6, supraorbital sensory pores 1 to 6; wc, weberian complex and capsule. Scale bar = 1 mm.

cartilaginous tips. Pharyngobranchial 4 ossified, suspending upper pharyngeal tooth plate. Teeth on upper pharyngeal tooth plate conical, arranged in two rows; eight teeth in main row ( Fig. 6 ).

Cephalic sensory canals enclosed in bone, with some branches deeply embedded. Head sensory canals with simple tubes, each ending in single pore. All canals continuous and connected to each other. Supraorbital sensory canal running along frontal and nasal bones, giving off three paired pores: pore s1 placed between palatine and mesethmoid, pore s3 between anterior margin of frontal and vomer, and pore s6 on frontal, close to lateral border. Pores s1 and s3 placed between anterior margin of frontal and vomer. Pore s6 opening laterally on supraorbital sensory branch, not emerging from epiphyseal branch. Supraorbital canal joining infraorbital canal on anterior part of sphenotic. Infraorbital canal incomplete, running along head surface, giving off two branches, anterior one with pores i1 and i3, connected by single canal, both close to lacrimal, anteriorly to eye; posterior one with pores i10 and i11 connected through single canal, near sphenotic border, ventroposteriorly to eye. Postotic sensory canal extending from posterior limit of optic sensory canal to anterior limit of lateral line, with pore p1 opening on pterotic border. Preopercle-mandibular sensory canal absent. Otic sensory canal short, without pores. Lateral-line canal very short, with three pores. Pore ll1 on postemporal-supracleithrum, pores ll2 and ll3 on lateral side of body posterior to opercle.

Dorsal-fin ii,7, its margin somewhat rounded, with four procurrent rays. Basal dorsal-fin radials eight. Dorsal-fin base located between verticals through 20 th and 25 th vertebra (n = 3). Pectoral fin i,6. Some specimens with minute filamentous extension to tip of first unbranched pectoral-fin ray; others without such extension. Pelvic fin i,4, small with margin rounded, origin located at vertical through about 17-18 th vertebrae. Anal fin ii,5, with three procurrent rays. Anal-fin pterygiophores arranged as six thin, elongate proximal radials and five very small, completely cartilaginous distal radials. Caudal fin truncated, 6+5 principal rays (n = 15); dorsal procurrent rays 12; ventral procurrent rays 10-12*. Precaudal vertebrae 12-13. Total vertebral 36 (n = 3). Paired pleural ribs 5-6 (n = 3), becoming progressively thinner anteroposterioly. Sixth unpaired rib present only on right side in smallest c&s specimen examined (UFBA 5286).

Color in alcohol. Body color pale brown to light gray, somewhat homogeneous, with minute dark chromatophores distributed throughout; ventralmost lateral portion clearer; ventral surface white. Dorsal surface of head with dark brown area at nape. Nasal barbel dark brown; maxillary barbel pigmented dorsally; rictal barbel light yellow. Dorsal and caudal fins with brown chromatophores along borders of rays; basal portion of dorsal-fin membrane pigmented similarly to body. Pectoral, pelvic and anal fins somewhat lighter, with dark chromatophores restricted to region near base of rays ( Fig. 1 ).

Chapada Diamantina, in northern Bahia State ( Dantas et al., 1992; Santos, 2008).

Habitat and ecology. Trichomycterus payaya was captured in two small streams (1 to 7 m wide and up to 1 m deep), characterized by somewhat turbid water and moderate current over sandy bottom with pebbles, relatively low altitude (505- 547 m above sea level), and surrounding vegetation mainly composed of grasses ( Fig. 9 ). The stomach contents of four specimens were analyzed (2 c&s, UFBA 5284, young male, 24.1 mm SL; MBML 2560, young female, 30.1 mm SL; 2 in alcohol, UFBA 5286, young female, 31.1 mm SL, and UFBA 5284, young male, 36.5 mm SL). Contents revealed the presence of Chironomidae larvae, Ephemeroptera nymphs, fragments of insects and organic matter. The new species was collected Live coloration. Ground color light yellow to somewhat translucent. Some specimens mottled with pale brown spots. Head pale yellow with scattered grayish-brown chromatophores. Dorsal portion of head with dark central area, posterior to eyes. Ventral surfaces translucent. Fins almost hyaline ( Fig. 7 ).

Distribution. Known from two tributaries of the rio Itapicurumirim, in the headwaters of the rio Itapicuru basin, northern Bahia State ( Fig. 8 ).

Etymology. The specific name payaya honors the Payayá, an indigenous people who once inhabited the area south of the rio São Francisco, between the upper rio Itapicuru and rio Paraguassu valleys to the Recôncavo Baiano, in northern Bahia State ( Dantas et al., 1992). The Payayá occupied the region called “Sertão da Jacobina” until the 18 th Century. Although the Payayá people are considered extinct for a long time, their descendents nowadays inhabit the region of the syntopically with Astyanax cf. lacustris , A. aff. fasciatus , Characidium sp., Gymnotus cf. carapo , Hoplias malabaricus , Parotocinclus bahiensis , Piabina argentea , Pimelodella itapicuruensis , Poecilia reticulata , Rhamdia quelen , Serrapinnus heterodon , S. piaba , and Steindachnerina sp.

Figures

Fig. 1. Trichomycterus payaya, holotype, MNRJ 36665, 37.4 mm SL. Brazil, Bahia, Miguel Calmon, riacho Olhos d’água on road BA-131, tributary to rio Itapicuru-Mirim, between Miguel Calmon and Jacobina; a. lateral, b. dorsal, and c. ventral views.

Fig. 3. Neurocranium and Weberian apparatus of Trichomycterus payaya, UFBA 5286, paratype, 31.4 mm SL. Ventral view.Abbreviations: ap, autopalatine; ep, epioccipital; fl, fronto-lacrimal tendon bone; fr, frontal; gf, foramen for anterior branch of glossopharyngeal nerve; i10, i11, infraorbital sensory pores 10 to 11; le, lateral ethmoid; me, mesethmoid; mx, maxilla; of, optic foramen; os, orbitosphenoid; pa, parasphenoid; pm, premaxilla; ps, posttemporosupracleitrum; pt, pterotic; sp, sphenotic; tf, foramina for trigeminofacial nerve branches; vf, foramen for vagus nerve; vo, vomer; wc, weberian complex and capsule. Scale bar = 1 mm.

Fig. 4. Left suspensorium of Trichomycterus payaya, UFBA 5286, paratype, 31.4 mm SL. Lateral view. Abbreviations: hy, hyomandibula; io, interopercle; mt, metapterygoid; op, opercle; po, preopercle; qu, quadrate. Scale bar = 1.5 mm.

Fig. 5. Left hyoid arch of Trichomycterus payaya, UFBA 5286, paratype, 31.4 mm SL. Ventral view.Abbreviations: ac, anterior ceratohyal; br, branchiostegal rays; ic, interceratohyal cartilage; pc, posterior ceratohyal; vh, ventral hypohyal; ur, urohyal. Scale bar = 1 mm.

Fig. 6. Branchial skeleton of Trichomycterus payaya, MBML 2533, paratype, 31.1 mm SL. Dorsal view (right dorsal elements and gill rakers not shown). Abbreviations: bb2 to bb4, basibranchial 2 to 4; cb1 to cb5, ceratobranchials 1 to 5; dp, dentigerous plate; eb1 to eb5, epibranchials 1 to 5; hb1 to hb3, hypobranchials 1 to 3; pb3 to pb4, pharyngobranchials 3 and 4. Scale bar = 1 mm.

Fig. 7. Trichomycterus payaya, living specimens photographed in afield aquarium shortly aftercollection.Photo by O.T.Oyakawa.

Fig. 9. Type locality of Trichomycterus payaya, Brazil, Bahia, Miguel Calmon, riacho Olhos d’água, rio Itapicuru basin.

Fig. 8. Eastern Brazilian drainages between rio São Francisco and rio Paraíba do Sul, illustrating the distribution of the Trichomycterus species in the area, location of Miguel Calmon Municipality in Bahia State and in Brazil, and details of collecting localities of Trichomycterus payaya in the rio Itapicuru drainage, and neighbor river basins.