Hypostomus peckoltoides, Zawadzki & Weber & Pavanelli, 2010

Zawadzki, Cláudio Henrique, Weber, Claude & Pavanelli, Carla Simone, 2010, A new dark-saddled species of Hypostomus (Siluriformes: Loricariidae) from the upper rio Paraguay basin, Neotropical Ichthyology 8 (4), pp. 719-725 : 720-723

Hypostomus peckoltoides , new species Figs. 2-3

Hypostomus sp. : Werner et al., 2005: 302 (“L390”, photo 3; “rio Cuiabá”).

Hypostomus sp. 5 - Veríssimo et al., 2007: 6 (checklist, Manso Reservoir, upper rio Paraguay basin, Brazil).

Holotype. MZUSP 105226, 110.7 mm SL, Brazil, Mato Grosso State, Municipality of Santo Antônio do Leverger, rio Cuiabá, upper rio Paraguay basin, 15 o 58’26”S 55 o 56’26”W, 19 Jun 2000, Nupélia staff. Paratypes. Same data as holotype, except when noticed. ANSP 188923, 1, 75.5 mm SL, 24 May 2000. MHNG 2691, 1, 82.8 mm SL, 24 Aug 2003. NUP 2613, 1, same data as holotype, 24 Aug 2003. NUP 5216, 2, 88.9-92.8 mm SL, 23 Aug 2000. NUP 5217, 3, 85.5-98.2 mm SL, 20 Jun 2000. NUP 5218, 3, 80.7-86.4 mm SL. ZSM 39427, 1, 90.3 mm SL, rio Cuiabá, collector and date unknown. Diagnosis. Hypostomus peckoltoides is distinguished from all congeners, with exception of young specimens of H. latifrons , by the presence of wide dark transverse bars on body and bands on the fins (vs. body entirely dark or with pale or dark spots); and by the conspicuous dark vermiculations on abdominal region (vs. abdominal region entirely dark or with pale or dark spots). From H. latifrons it differs by having the dark bars on the sides and bands on the fins in adults (vs. spots present anteriorly and dark blotches porsteriorly in adults), and by having just one pre-dorsal plate margining the supraoccipital (vs. three plates).

Description. Counts and measurements in Table 1. Head stout and slightly compressed. Body width at cleithral region considerably greater than head depth and almost equal to head length.Anterior profile of head weakly triangular in dorsal view. Eye moderately small (17.9-20.6% of HL), latero-dorsally placed. Interorbital space straight in frontal view. Median ridge on snout slightly evident. Short, round ridges on dorsal surface of head, lateral to nares, passing above eyes and onto pteroticsupracleithrum. Pterotic-supracleithrum with slightly larger odontodes than those on remaining dermal bones. Supraoccipital with weak longitudinal median ridge and a posterior process bordered by a single plate (two fused plates to each other in one specimen). Dorsal and lateral region of body covered with dermal plates except for tip of snout and base of dorsal fin. Predorsal region with rounded and inconspicuous longitudinal ridge. Lateral surface of body with five longitudinal series of plates. Dorsal series starting just below dorsal-fin origin; weakly keeled from origin to about adipose-fin spine insertion. Mid-dorsal series weakly keeled until transverse line below insertion of last branched dorsalfin ray. Median series not keeled and bearing lateral line. Midventral series not keeled, except weak keel on first four to five plates. Ventral series weakly keeled from vertical line above anal-fin spine insertion to end of caudal peduncle.

Snout obtuse; narrowed anteriorly; elevating in lateral profile to an angle of approximately 45 o. Dorsal profile rising abruptly from tip of snout to interorbital region and elevating convexly and more slightly from this point to dorsal-fin origin; decreasing from dorsal-fin origin to region of procurrent rays of caudal fin, then elevating again for short space until end of caudal peduncle. Caudal peduncle oval in cross-section, compressed dorsally from end of dorsal-fin insertion to origin of adipose fin and ventrally on its whole extension. Lateral line complete except for triangular plate at base of caudal.

Lips relatively small, transversally ovoid. Outer edge of upper lips without platelets. Lower lip far from reaching pectoral girdle, its inner surface covered with numerous little papillae. Maxillary barbel approximately equal to orbital diameter. Teeth relatively robust, with elongated crown and small lateral cuspid. Dentary rami form an angle of approximately 120 o.

Lower surface of head plated laterally, with naked area extending medially from beneath lower lip to anterior border of pectoral girdle. Pectoral girdle totally plated and abdomen almost totally covered with minute platelets.

C. H. Zawadzki, C. Weber & C. S. Pavanelli 721

Dorsal fin moderate; V-shaped spinelet followed by flexible spine and seven branched rays; distal tips of posterior rays just reaching preadipose plate; its posterior border straight. Adipose fin curved posteriorly; relatively well-developed. Pectoral fin with a slightly medially curved spine and six branched rays; its posterior border straight. Pectoral-fin spine covered with well-developed odontodes more developed distally and in larger specimens; when medially adpressed reaching about half pelvic-fin unbranched ray length. Pelvic fin with slightly medially curved and ventrally flattened unbranched ray and five branched rays; when medially adpressed reaching a line about one-third anal-fin unbranched ray; its border almost straight. Anal fin reaching sixth plate after its origin; its border straight. Caudal fin with two outer unbranched rays and 14 inner branched rays; furcate, with ventral lobe longer than dorsal one.

Color in alcohol. Ground color of dorsal surface of head and body grayish. Head, dorsum and flanks covered with many dark transverse bars of irregular forms, with several of the bars merging randomly. On head the bars are closer to each other, sometimes fused and covering most of head; towards posterior portions of body the bars are more conspicuous, and increase in width and in distance from each other. Dorsal, pectoral, pelvic and caudal fins with four to five usually conspicuous dark bands. Adipose fin with one dark transversal band and anal fin with two dark bands.

Color in life. The specimen ZSM 39427 ( Fig. 3 ) when alive presented small and irregular dark saddles scattered over dorsal region of head, predorsal region and pectoral fin. The posterior region of body and remaining fins have wide and irregular, but not reticulate, dark transversal saddle-like bands. Dorsal, pelvic and caudal fins presented three to four dark conspicuous irregular bands.

Etymology. The specific name refers to the genus Peckoltia , which includes species with dark saddles similar to that found in the new species. The word comes from the name of the genus proposed by Miranda-Ribeiro (1912), honoring Mr. Gustavo Peckolt, plus the Greek suffix -öides meaning to resemble.

722 A new dark-saddled species of Hypostomus

Distribution and habitat. Hypostomus peckoltoides is known from its type-locality, rio Cuiabá, upper rio Paraguay basin, Brazil. The rio Cuiabá is formed by the joint of the rio Cuiabazinho and the rio Manso, nearby Nobres City, to be the first major tributary to the rio Paraguay, where it flows south of Cuiabá Municipality. These environments have turbid water, rocky with sand substrate, and variable remnant riparian vegetation. The new species was found syntopically

C. H. Zawadzki, C. Weber & C. S. Pavanelli 723 occurring with H. boulengeri , H. cochliodon , H. latifrons , H. latirostris , H. regani and another putative undescribed species of Hypostomus .

Figures

Fig. 2. Hypostomus peckoltoides, holotype, MZUSP 105226, 110.7 mm SL, from the rio Cuiabá, upper rio Paraguai basin, Mato Grosso State, Brazil.

Fig. 3. Hypostomus peckoltoides, paratype, ZSM 39427, 90.3 mm SL. Photographed alive byAndre Werner.