Rineloricaria osvaldoi, Fichberg & Chamon, 2008

Fichberg, Ilana & Chamon, Carine C., 2008, Rineloricaria osvaldoi (Siluriformes: Loricariidae): a new species of armored catfish from rio Vermelho, Araguaia basin, Brazil, Neotropical Ichthyology 6 (3), pp. 347-347 : 347-

Rineloricaria osvaldoi , new species

Figs. 1 , 2 and 3

Holotype. MZUSP 89022 , male, 126.3 mm SL, Brazil, Goiás, Município Goiás, rio Araguaia basin, rio Vermelho at bridge on road GO- 164, 15 o 54’11"S 50 o 6’55"W, 23 Jun 2005; C. Chamon, M. Melo, L. M. Sousa & L. Souza.

Paratypes. MZUSP 98544 , 10 , 30.1 - 124.1 mm SL, 1 c&s, 91.5 mm SL, same data as the holotype . ANSP 187421 , 4 , 81.0-51.9 mm SL, same data as the holotype . MZUSP 89075 , 8 , 31.9 - 168.3 mm SL, Brazil, Goiás, Goiás, rio Araguaia basin, rio Bugre, drainage of rio Vermelho , at bridge on road GO- 164, 25 km NW of Goiás, 15 o 47’13"S 50 o 7’53"W, 24 Jun 2005, C. Chamon, M. Melo, L. M. Sousa & L. Souza . AUM 47713, 6 , 72.9 - 63.3 mm SL, Brazil, Goiás, Goiás, rio Araguaia basin, rio Bugre, drainage of rio Vermelho , at bridge on road GO- 164, 25 km NW of Goiás; 15 o 47’13"S 50 o 7’53"W, 24 Jun 2005, C. Chamon, M. Melo, L. M. Sousa & L. Souza . MZUSP 4912 , 5 , 48.5 - 91.5 mm SL, Brazil, Goiás, Goiás, rio Vermelho, 14 Sep 1966, Expedição do Departamento de Zoologia .

Diagnosis. The new species can be distinguished by its congeners by the following combination of features: thoracic ventral surface trapezoidal with greatest width between pectoral fins (vs. retangular or square shape with the same width at pectoral fins and at the origin of pelvic fin); up to 13 premaxillary teeth (vs. up to 10 in all congeners, except R. aequalicuspis with 15, R. castroi with 15, and R. uracantha with 12); up to 13 dentary teeth (vs. up to 10 in all congeners, except R. aequalicuspis with 20, R. castroi , with 12, and R. uracantha with 12); largest width of the body at the canal plate (vs. at cleithrum in R. altipinis , R. baliola , R. beni , R. castroi , R. heteroptera , R. fallax , R. formosa , R. lanceolota , R. latirostris , R. misionera , R. nigricauda , R. parva , R. pentamaculata , R. phoxocephala , R. quadrensis ).

Description. Morphometric data of holotype and paratypes in Table 1. Head and body strongly depressed. Dorsal profile slightly concave from snout tip to dorsal-fin origin and straight from this point to caudal-fin origin. Greatest body depth at posterior border of parieto-supraocciptal; least body depth at caudal peduncle.

Head short. In dorsal view, head rounded to triangular in females and immature males with tip of snout and distal margin of opercle rounded ( Fig. 3 ); head margin of mature males strongly rounded, shaped as semicircle ( Figs. 3 a-b). Snout with very small, elliptical, naked area, not reaching most anterior pore of infraorbital ramus of sensory canal.

Predorsal area weakly keeled with small odontodes covering plates; posterior margin of compound-pterotic with dark-brown spots around first pores of lateral-line canal. Eyes elliptical with large, deep postorbital notch.

Mouth opening large. Upper lip very short and separated from naked area of snout by extremely thin row of plates (sometimes absent) covered by tiny odontodes; margin of upper lip adorned with rounded papillae. Two or three rows of papillae between anteroventral border of upper lip and anterior border of premaxillary ramus; lower lip covered by irregularly sized papillae well organized and arranged concentrically around oral cavity; edge of lower lip fringed, triangular in shape. Short maxillary barbel adorned with very small papillae; teeth acute and strongly bicuspidate; dentary teeth larger than those of premaxilla; 5-13 (8) teeth on premaxilla and 5-13 (7) on dentary; accessory cusp almost same size as principal cusp.

Body covered by 26-29 (27) plates on median series, coalescent plates on 16-19 (17) and, 6-7 (6) lateral abdominal

I. Fichberg & C. C. Chamon 349

plates. Five longitudinal rows of plates at dorsal-fin origin. Lateral plates weakly keeled with odontodes along lateral line pores slightly better developed than those on rest of body.

Ventral region completely covered by plates, from cleithrum to caudal peduncle. Ventral plates well organized in three sections. Anterior section consisting of small quadrangular plates on pectoral girdle area, middle section includes large, trapezoidal plates between pectoral and pelvic girdles, and posterior section represented by preanal shield formed by three large plates surrounding polygonal preanal plate.

Dorsal-fin rays i,7, pectoral-fin rays i,6, pelvic-fin rays i,5, anal-fin rays i,5, caudal-fin rays i,10,i; adpressed pectoral fin in females and immature males surpassing pelvic fin by approximately 15% of length of first unbranched ray of pelvic fin. Pelvic fin reaching insertion of anal fin. Caudal fin truncate, with short, thin filament on dorsal caudal-fin ray. Lower caudalfin ray without filament.

Color in alcohol. Dorsal surface light-brown covered by dark dots along body, more concentrated on head. Skin around

350 Rineloricaria osvaldoi : a new species of armored catfish from rio Vermelho pores of sensory system dark, especially around infraorbitals. Five dark brown transversal bars along body. First bar at dorsal-fin origin, second bar just posterior to dorsal-fin base and other bars located along caudal peduncle. In some specimens, bars light brown and inconspicuous. Chromatophores widely concentrated on posterior edge of compound-pterotic forming dark conspicuous area. All fins covered by dark dots aligned through rays. Caudal fin with two vertical dark bars: broad one basally and narrow one at distal margin. Ventral surface pale ochre, without bars or dots.

I. Fichberg & C. C. Chamon 351

Sexual dimorphism. Head margin of mature males rounded, with abundant hypertrophied odontodes extending from postrostral plates to opercle, along margin of head (see Fig. 3a ); pectoral-fin unbranched ray thick, curved and shorter than in females; unbranched pectoral-fin ray and first four branched rays covered dorsally by numerous, well developed odontodes.

Geographic distribution. Rineloricaria osvaldoi is only known from the rio Vermelho and it tributary, the rio Bugre, in the rio Araguaia basin, Brazil ( Figs. 4-5 ).

Ecological notes. The specimens were collected in clear water over a sand bottom with some rocks, at the altitude of approximately 496 meters above sea level. Both expeditions

352 Rineloricaria osvaldoi : a new species of armored catfish from rio Vermelho were carried out in dry season when the waters were low.

Etmology. The name of the new species is given in honor of Dr. Osvaldo Takeshi Oyakawa, the collection manager of the fish collection of the Museu de Zoologia da Universidade de São Paulo and also a specialist of the Loricariinae , particularly of the genus Harttia .

Figures

Fig. 1. Rineloricaria osvaldoi, holotype, MZUSP 89022, male, 126.3 mm SL; rio Vermelho, rioAraguaia basin, Brazil; dorsal, lateral and ventral views.

Fig. 2. Rineloricaria osvaldoi, holotype, MZUSP 89022, male, alive, prior to fixation.

Fig. 3. Rineloricaria osvaldoi, dorsal and ventral views of the anterior region of the body (a and b, male, MZUSP 89022 126.3 mmSL,c and d, female,MZUSP 89075,125.7 mmSL).

Fig. 4. Distribution of Rineloricaria osvaldoi. Pentagon = rio Vermelho (type locality); square = rio Bugre.

Fig. 5. Type locality of Rineloricaria osvaldoi, rio Vermelho, rioAraguaia basin, Brazil.