Hypostomus tapijara, Osvaldo T. Oyakawa, Alberto Akama & Angela M. Zanata, 2005

Osvaldo T. Oyakawa, Alberto Akama & Angela M. Zanata, 2005, Review of the genus Hypostomus Lacépède, 1803 from rio Ribeira de Iguape basin, with description of a new species (Pisces, Siluriformes, Loricariidae)., Zootaxa 921, pp. 1-27 : 19-23

Hypostomus tapijara sp. n.

(Fig. 1B, 7, 8; Table 2)

Plecostomus commeosoni (lapsus calami pro commersoni) Miranda-Ribeiro, 1907:188 [reference, distribution].

Plecostomus commersoni . Miranda-Ribeiro, 1908a:4 [reference, distribution]. Miranda-Ribeiro, 1908b: (unnum. pp) [reference, distribution].

Plecostomus commersonni (lapsus calami pro commersoni) Miranda-Ribeiro, 1918:710 [reference, distribution].

Holotype. Brazil. São Paulo: MZUSP 55204, 378.3 mm SL; rio Catas Altas, Ribeira; M. R. Santos & C. E. Espírito Santo, 14 October 1995.

Paratypes. Brazil. São Paulo: - MZUSP 55205, 1, 264.2 mm SL; collected with the holotype. - MZUSP 38582, 3, 229.0-325.0 mm SL; rio Pardo, tributary of rio Turvo, Água do Padre district, Barra do Turvo; O. T. Oyakawa et al., 5-6 February 1987. - MZUSP 61728, 1, 47.3 mm SL; rio Batatal, tributary of rio Ribeira de Iguape, approx. 24º 35' 26,3"S, 48º 16' 23,9"W, Iporanga; Projeto Biota/Fapesp Ribeira, 12 May 2000. - MZUSP 52858, 1, 304.3 mm SL; rio Ribeira de Iguape, Iporanga; S. Buck et al., 20 October1998. - MZUSP 37544, 1, 160.8 mm; Canal do Valo Grande, Cananéia; Cetesb, MayJuly1984. - MZUSP 24632, 3, 84.1-154.4 mm SL; rio Ribeira de Iguape, Registro; J. Mandelli Jr., 6 April 1978. - MZUSP 3655, 5, 105.4-124.5 mm SL; Iporanga; Vieira & Lima, 1944. - MZUSP 37589, 2, 130.7-163.1 mm SL; rio Ribeira de Iguape, Registro; J. Mandelli Jr., 17 October 1978. - MZUSP 45416, 2, 238.1-304.0 mm; rio Ribeira de Iguape, close to mouth of rio Pilões and 8 km upstream of rio Batatal, Eldorado; M. Damato, 28 February 1993. - MZUSP 45200, 5, 18.8-40.3 mm SL; tributary of rio Ribeira de Iguape, 8km above rio Batatal, Eldorado; M. Damato, 05 March 1993. - MZUSP 45428, 1, 310.0 mm SL; rio Ribeira de Iguape, close to mouth of rio Pilões and 8 km upstream of rio Batatal, Eldorado; M. Damato, 1 March 1993. - MZUSP 52857, 2, 284.6-262.2 mm SL; rio Ribeira de Iguape, close to mouth of rio Betari, Eldorado; S. Buck et al., 24 March 1994. - MZUSP 55216, 2, 197.7-239.1 mm SL; rio Pardo, Barra do Turvo; M. R. Santos & C. E. Espírito Santo, October 1995. - MZUSP 38652, 1, 24.1 mm SL; creek Pariqueramirim, tributary of rio Ribeira de Iguape, Pariquera-Açú; Estagiários MZUSP, 29 March 1987. - ANSP 180330, 2, 240.0-333.0 mm SL; rio Pilões, Iporanga; M. R. Santos & C. E. Espírito Santo, 19 January 1995. - MCP 35596, 3, 183.8-267.6 mm SL; rio Juquiá, Juquiá; M. R. Santos & C. E. Espírito Santo, 11 October 1995. - MNRJ 27503, 3, 220.0- 268.5 mm SL; rio Pilões, Iporanga; M. R. Santos & C. E. Espírito Santo, 12 October 1995.

Non-type material examined: Brazil. São Paulo: - MZUSP 55212, 1, 268.0 mm SL; rio Iporanga, Iporanga; M. R. Santos & M. Morato, 17 January 1995. - MZUSP 55213, 10, 148.0-321.0 mm SL; rio Catas Altas, Ribeira; M. R. Santos & M. Morato, 23 January 1995. - MZUSP 55477, 2, 175.2-274.5 mm SL; rio Pardo, Barra do Turvo; M. R. Santos & M. Morato, 25 January 1995. - MZUSP 42800, 4, 174.4-202.0 mm SL; rio Ribeira de Iguape, Ribeira; Expedição MZUSP, 8-27 March 1991. - MZUSP 40200, 1, 181.5 mm SL; rio Pardo, Barra do Turvo; SEMA/SUDELPA. - MZUSP 62887, 1, 250,0 mm SL, Rio Uma do Prelado, Estação Ecológica Juréia Itatins, Peruíbe; Milena, 26 June, 2000.

Diagnosis: Hypostomus tapijara is distinguished from its congeners inhabiting rio Ribeira de Iguape basin by the presence of well defined large, dark, and roundish spots somewhat homogeneously distributed over body and fins, and by its relative broad dorsal fin (interradial membranes wider than other eastern drainage Hypostomus species). In addition, it differs from H. agna by the presence of well-developed keels on lateral plates of body, mid-dorsal series of plates of pre-dorsal region of trunk not aligned to any series of plates posterior to this point, and caudal peduncle ovoid in cross-section. Hypostomus tapijara can be further distinguished from H. interruptus by the absence of dark bands on flanks. Finally, H. tapijara also differs from H. ancistroides by having the ventral region of head completely covered with dermal ossifications.

Description: Standard length of examined specimens 18.8 to 378.3 mm SL. Counts and proportional measurements presented in Table 2. Dorsal profile slightly convex, raising abruptly upwards from snout tip to dorsal-fin origin, and gently descending from this point to the end of caudal peduncle. Caudal peduncle roughly oval in cross-section; slightly flattened on ventral portion. Dorsal plates between end of dorsal fin base and adipose fin spine flattened. One preadipose plate.

Pre-dorsal region of trunk located between pterotic-supracleithrum and vertical through dorsal-fin origin covered by three horizontal series of plates that extends posteriorly to the caudal fin. Median series of plates bearing the lateral-line canal. Mid-dorsal series situated above and mid-ventral series situated below median series. Dorsal series of plates starting at dorsal-fin origin. Ventral series of plates starting above the insertion of the pelvic-fin. Mid-dorsal series of lateral plates of pre-dorsal region in medium or large specimens not aligned to posterior portion of this series; center of those plates relatively aligned or slightly ventral to dorsal border of plates of the posterior portion of mid-dorsal series, situated posterior to vertical through dorsal-fin origin (Fig. 1B). Specimens of 110.0 mm SL or smaller with mid-dorsal series of plates somewhat aligned throughout its extension. Covering of abdomen ontogenetically variable; completely naked in specimen around 47.0 mm SL; usually covered with minute platelets, leaving a small naked area just around the pelvic fin in larger specimens.

Body with four well-developed keels along flanks, except for specimens under 90.0 mm SL that have no keels. Dorsal-most keel situated on dorsal series of plates. Keel on mid-dorsal series of plates interrupted, following the alignment of plates. Anterior portion of this keel somewhat continuous with ridge on pterotic-supracleithrum, crossing mid-dorsal series of plates of pre-dorsal region of trunk, becoming somewhat posterodorsally oriented and not aligned to keel on plates of the posterior portion of mid-dorsal series. Keel on median series of plates well developed along its entire length. Mid-ventral keel originating immediately posterior to cleithrum, more conspicuous on anterior half of trunk.

Head triangular, somewhat pointed anteriorly, unless for specimens around 85.0 mm SL or smaller that have anterior profile of head distinctly rounded. Dorsal and ventral region of head completely covered with dermal ossifications, except for a small naked area on snout tip, which is reduced in the larger specimens. Outer face of upper lip covered with small platelets in specimens with 85.0 mm SL or larger. Ornamentation of pteroticsupracleithrum distinct from the remaining surface of head, with odontodes aligned and forming striae. Dorsal margin of orbit elevated, continuing in a low ridge on pterotic-supracleithrum. All examined specimens larger than 85.0 mm SL with a prominent ridge on supraoccipital, diverging in two separated ridges on predorsal plates. Usually one plate (only one specimen with two plates) bordering posterior margin of the supraoccipital bone. Space between orbits slightly convex. Eyes large.

Mouth rounded. Anterior-most papillae of inner face of lower lip irregular in form, somewhat elongate, followed by rounded papillae decreasing in size posteriorly. Teeth long and bicuspid; medial cusp approximately twice in length of outer cusp and curved inward. Premaxillary teeth inserted in a relatively straight line; contralateral dentary row of teeth inserted in a relatively acute angle. Maxillary barbels relatively long, slightly shorter than eye diameter, and with papillae near the base of its inner margin.

Dorsal-fin origin situated on vertical anterior to pelvic-fin origin, approximately at vertical through midlength of pectoral-fin spine. Dorsal fin relatively large; tips of adpressed last three rays reaching preadipose plate in smaller specimens and ending at third pair of plate before preadipose plate in the largest specimen examined. Margin of dorsal fin convex. Adipose-fin spine compressed, somewhat curved ventrally except in specimens of 47.0 mm SL that have this spine straight. Distal half of pectoral-fin spine of large specimens (around 200.0 mm SL) covered dorsally with well-developed odontodes, slightly curved forward. Tip of adpressed pectoral-fin positioned beyond origin of pelvic fin. Tip of adpressed pelvic-fin spine positioned beyond midlength of anal fin in juveniles and posterior to anal-fin origin in largest specimens examined. Basal lamina of first proximal radial of anal fin in small specimens covered by skin; uncovered in larger specimens. Caudal fin margin concave, lower spine longer than upper.

Color in alcohol. Dorsal and lateral surface of body with light brown ground coloration. Ventral surface pale to yellowish. Black or dark-brown roundish spots scattered all over dorsal and lateral surface of body; smaller, close together, and somewhat more irregular in form over head. Spots organized in four horizontal lines on portion of body posterior to dorsal-fin end in most specimens examined (except juveniles); usually one spot in each plate of this region. Somewhat less conspicuous and brownish spots on abdomen, except by clear area from coracoid to posterior margin of lower lip; specimen around 47.0 mm SL without ventral spots. Ventral surface of caudal peduncle in the majority of specimens examined commonly with one central horizontal brown stripe continuing posteriorly from anal fin, bordered by clear areas. Overall ground coloration of all fins light brown, scattered with roundish black or dark-brown spots. Spots on fins slightly larger, darker, and more concentrated than those on body. Dorsal-fin interradial membranes sometimes with two parallel series of spots along ray extension, unless for specimens with 47.0-85.0 mm SL that have fewer spots on dorsal fin, arranged in oblique series. Spots on caudal fin uniformly distributed, not forming series or bands.

Distribution and notes. Hypostomus tapijara is the largest loricariid living in Ribeira de Iguape river basin. The species occurs mostly in the channel of the largest rivers in the area, as exemplified by rivers Ribeira de Iguape, Catas Altas, Pardo, and Batatal (Fig. 8). Furthermore, H. tapijara is the only species of Hypostomus to occur in estuarine environment in Ribeira de Iguape basin, close to the area where Ribeira de Iguape river flows into the ocean, in Cananéia, São Paulo. Examination of loricariids deposited at MZUSP revealed that H. tapijara also occurs at the rio Una do Prelado, a coastal river system inside Estação Ecológica da Juréia-Itatins, north of Ribeira de Iguape system. The area of occurrence of H. tapijara varies from 13 m of altitude in Cananéia to 500 m in the locality of rio Catas Altas, Ribeira.

Etymology. From tapijara, the common name of the species among the local people, and which means in Tupi language the one who is sedentary or ancient dweller. A noun in apposition.