Pimelodus ortmanni Haseman, 1911

Garavello, Julio Cesar & Shibatta, Oscar Akio, 2007, A new species of the genus Pimelodus La Cépède, 1803 from the rio Iguaçu basin and a reappraisal of Pimelodus ortmanni Haseman, 1911 from the rio Paraná system, Brazil (Ostariophysi: Siluriformes: Pimelodidae), Neotropical Ichthyology 5 (3), pp. 285-292 : 286-287

Pimelodus ortmanni Haseman, 1911

Figs. 1 and 2

Pimelodus ortmanni (part) Hasemann, 1911: 379-380 (Type locality: rio Iguaçu , Porto União da Vitória, current União da Vitória, Paraná State, Brazil) .

Pimelodus ortmanni: Gosline, 1945: 4 l (ref.); Fowler, 1954: 558 (ref.); Severi & Cordeiro, 1994: 65 (rio Iguaçu, Porto União, rio Timbó, Pinhão, Paraná); Garavello et al., 1997:76 (rio Iguaçu, reservatório de Segredo, Paraná); Renesto et al., 2000: 810, fig. 1 (rio Iguaçu, Salto Caxias).

Diagnosis. This species can be distinguished from all other Pimelodus , except P. fur (Lütken, ex Reinhardt, 1874), P. heraldoi Azpelicueta, 2001 , and P. absconditus Azpelicueta, 1995 , by the color pattern composed of small, densely placed oval or circular dots on anterior region of trunk, becoming inconspicuous or disappearing on the caudal peduncle (vs. stripes along the body in P. albicans (Valenciennes, 1840) , P. albofasciatus Mees, 1974, P. ornatus Kner, 1858 and P. tetramerus Ribeiro & Lucena, 2006 ; uniform gray coloration or with very weak dark dots on anterolateral region in P. altissimus Eigenmann & Pearson in Eigenmann &Allen, 1942, P. argenteus Perugia, 1891 , P. atrobrunneus Vidal & Lucena, 1999 , P. blochii Valenciennes in Cuvier & Valenciennes, 1840, P. brevis Marini, Nichols & La Monte, 1933, P. jivaro Eigenmann & Pearson in Eigenmann & Allen, 1942, P. microstoma Steindachner, 1876, P. pohli Ribeiro & Lucena, 2006 and P. punctatus (Meek & Hildebrand, 1913); dots scattered in the trunk in P. coprophagus Schultz, 1944, P. grosskopfi Dahl, 1961, P. maculatus La Cépède, 1803 , P. mysteriosus Azpelicueta, 1998 , P. navarroi Schultz, 1944, P. paranaensis Britski & Langeani, 1988 , P. pictus Steindachner, 1876 and P. platicirris Borodin, 1927 ). Differs from P. fur by smaller maxillary barbell length (1.3-1.8 in SL vs. 0.9 to 1.1), greater snout length (2.1 to 2.4 in HL vs. 3.1 to 3.5), greater eye diameter (3.5 to 4.9 in HL vs. 5.2 to 6.6), greater eye-operculum distance (2.9 to 3.5 in HL vs. 4.8 to 5.1), greater interorbital distance (3.6 to 5.1 in HL vs. 5.5 to 7.6), greater mouth width (2.6 to 3.5 in HL vs. 5.0 to 5.3); from P. heraldoi by smaller predorsal length (2.7 to 2.9 in SL vs. 2.5 to 2.6), smaller caudal peduncle depth (12.2 to 15.0 in SL vs. 11.3-12.6), greater snout length (2.1 to 2.4 in HL vs. 2.9 to 3.3), greater eye diameter (3.5 to 4.9 in HL vs. 5.2 to 6.3), greater eye-operculum distance (2.9 to 3.5 in HL vs. 4.7-5.1), greater mouth width (2.6 to 3.5 in HL vs. 4.3 to 5.4); and from P. absconditus by smaller pre-dorsal length (2.7 to 2.9 in SL vs. 2.4 to 2.6 in SL), smaller pre-pelvic length (2.0 to 2.1 in SL vs. 1.8 to 2.0 in SL), smaller caudal peduncle depth (12.2 to 15.0 in SL vs. 9.8 to 11.9 in SL) and smaller pectoral girdle width (5.4 to 6.2 in SL vs. 4.8 to 5.4).

Description. Morphometric data presented in Table 1. Dorsal profile of head inclined, slightly convex from tip of snout to dorsal-fin origin; slightly concave or almost straight from dorsal-fin insertion to adipose-fin origin; inclined and straight at dorsal-fin base; concave at caudal peduncle. Dorsal fin slightly anterior to median vertical line of trunk. Body depth, anterior to dorsal-fin insertion, less than body width at posterior cleithral process. Shape of head roughly conical in dorsal view, wedgelike in lateral view. Predorsal plate anteriorly V-shaped, surpassing supraoccipital process. Large orbital diameter, 0.7 to 1.4 (mean 1.0) in interorbital distance. Origin of frontal fontanel between posterior nares, not reaching to vertical through posterior orbit; mouth inferior; inferior mandible shorter than superior, fleshy lips in both. Villiform teeth in premaxillary and dentary tooth plates; premaxillary plate with semicircular anterior border, undivided at symphysis; dentary plate elongated, distally pointed, divided at symphysal region; maxillary barbel in adult specimens reaching anterior region of adipose fin, median portion in juvenile specimens. External mental barbel reaching but not surpassing pectoral fin insertion; in juveniles, reaching vertical through dorsal-fin origin; internal mental barbel reaching opercular membrane, sometimes surpassing it, never reaching pectoral-fin origin; ventral profile convex from inferior mouth to anal-fin base, concave on caudal peduncle. Body depth always shorter than head length. Caudal peduncle shallow. Pectoral fin reaching vertical through third or fourth ray of dorsal fin in juvenile specimens. Pelvic fin beginning at vertical through last ray of dorsal fin, not surpassing adiposefin origin when adpressed. Adipose fin elongated, its length similar to head length; anal fin triangular in lateral view, posterior margin concave. Caudal fin bifurcate, upper lobe longer than lower. Posterior cleithral process nearly triangular, short, not reaching vertical through dorsal-fin origin, sometimes reaching vertical through median predorsal plate. Unbranched dorsal-fin ray pointed, anterior margin completely smooth, small and pointed hooks posteroventrally in posterior margin; large hooks covering its superior third on distal region. Anterior margin of pectoral-fin spine smooth, small and pointed hooks on almost entire distal region of posterior margin; hooks absent in base. Dorsal fin rays II,6 (only one specimen II,7); pectoral fin I,8-10; pelvic fin i,5; anal fin i-iv,8-10; caudal fin i,7,8,i. Gill-rakers 19-25 on the first left branchial arch.

Color in alcohol. Dorsal region light gray, ventral region light brown; dark brown oval blotches in series of six to ten, shorter than orbital diameter, neatly positioned in sequence along flanks of body, spots inconspicuous or absent on caudal peduncle; small dark brown dots on parietal, supraoccipital, infraorbital and opercular regions; five dark brown blotches in posterior region of cleithral process; dark brown dots on rays of dorsal fin; inconspicuous gray horizontal line in upper half of dorsal fin; two or three irregular series of small dark dots or ligth adipose fin. Pectoral, pelvic, and anal fin sometimes light gray for almost one-third of fin; pectoral fin completely gray; pelvic fin grayish on base and on distal third; dark dots only on upper lobe of caudal fin, dark brown line crossing three branched rays of lower lobe.

Distribution. Broadly distributed throughout the rio Iguaçu basin ( Fig. 3 ).

Figures

Fig. 1. Lateral view of Pimelodus ortmanni, FMNH 54240, holotype, 164.0 mm SL, rio Iguaçu, União da Vitória.

Fig. 2. Lateral view of Pimelodus ortmanni, MZUSP 50052, 265.0 mm SL, rio Iguaçu, downstream from Salto Osório dam, Quedas do Iguaçu.

Fig. 3. Geographical distribution of Pimelodus ortmanni and Pimelodus britskii from Rio Iguaçu. Each symbol may represent more than one sample.