Liosomadoras morrowi Fowler, 1940

Birindelli, José L. O. & Zuanon, Jansen, 2012, Systematics of the Jaguar catfish genus Liosomadoras Fowler, 1940 (Auchenipteridae: Siluriformes), Neotropical Ichthyology 10 (1), pp. 1-11 : 6-7

Liosomadoras morrowi Fowler, 1940

Fig. 11

Liosomadoras morrowi Fowler, 1940: 226 [type locality: Ucayali river basin, Contamana, Peru]. - Gosline, 1945: 15 [catalog, included in Doradidae ] - Rössel, 1962: 30 [name mentioned in text as considered to belong to the family Auchenipteridae , instead of Doradidae ]. - Mees, 1978: 272 [considered junior synonym of Arius oncinus ]. - Burgess, 1989: 241 [ornamental fish catalog]. - Burgess, 1994: 90 [revalidation, based on live Aquarium specimens, not preserved in fish collections]. - Eschmeyer, 1998: 1123 [catalog]. - Ferraris, 2003: 475 [catalog, considered a valid species]. - Ferraris, 2007: 75 [catalog].

Diagnosis. Liosomadoras morrowi is readily distinguished from L. oncinus by the coloration, L. morrowi having widespread (non-organized) dark round blotches on body in specimens of all sizes (vs. two longitudinal rows of about seven large squarish dark-brown blotches on body in small specimens [up to 60 mm SL], which during growth become pale inside and start to fragment into opened blotches and

J. L. O. Birindelli & J. Zuanon 7

then, eventually, into widespread small spots, some still forming a fragmented open square [in specimens of 100 mm SL or more]), and for having midlateral line of body colored as the remaining lateral portion of body (vs. midlateral line of body pale, without dark blotches or spots).

Description. Morphometric data for Liosomadoras morrowi is presented in Table 1. Species moderately sized (largest examined specimen 103.3 mm SL) with somewhat depressed head and body, terminal mouth with prognathous jaw. Eye relatively small, anteriorly positioned on head; posterior cleithral process long, shallow, with several rows of spines. Dorsal-fin rays II,6 (n = 6); pectoral-fin rays I,6 (n = 6); pelvic-fin rays i,6 (n = 6); anal-fin rays iii,10 or 11 (mode 11, n = 6); caudal-fin rays i,7,8,i (n = 6). Dorsal-fin spine robust, with approximately 20 strong serrations on anterior face and about 10 on posterior face; pectoral-fin spine robust, with strong serrations on both anterior and posterior faces. Axillary pore with single opening, located immediately ventral to base of posterior cleithral process. Adipose fin thick, with base slightly larger than anal-fin base. Anal fin short, with lobe length slightly larger than base length. Lateral line complete; few transverse rows of free neuromasts dorsal to lateral-line canals, usually visible as clear areas on body. Caudal fin weakly forked, ventral lobe slightly larger than dorsal one. Gas bladder occupying most of dorsal portion of body (pleuroperitoneal) cavity; apple-shaped or abbreviated cordiform with internal T-shaped septum ( Birindelli et al., 2009: fig. 2).

Coloration. Ground color tan to brown or gray, slightly countershaded. Large round dark blotches widespread (and unorganized) on body, head and fins. Dark blotches larger than eye diameter, and proportionally larger in smaller specimens ( Fig. 11 ). Neuromasts of lateral line and transversal lines dorsal to lateral line with pale border. Ventral portions of head and abdomen pale cream, usually without spots.

Although no live specimen was examined, in the available illustration of a live specimen ( Burgess, 1989: 88, unnumbered figure), the coloration is similar to described above based on alcohol-preserved specimens, except for being overall darker.

Sexual dimorphism. No nuptial male was available for inspection. However, a non-nuptial male show a modified anal fin as in otherAuchenipterinae, with the genital papilla located in a tube attached to the anterior border of the anal fin, and opening at the distal edge of the last unbranched ray.

Distribution. Liosomadoras morrowi is known from the río Ucayali basin, from Contamana to Iquitos, in eastern Peru, and from the rio Jutaí, rio Purus, and Lago Amanã near Tefé, in northwestern Brazil.

Ecology. As with Liosomadoras oncinus , there is no published information on the biology and ecology of L. morrowi in its natural habitat. Specimens were collected in cavities of submerged tree trunks (INPA 25415), or in association with floating macrophyte mats (INPA 35282).

Etymology. Named in honor of Mr. William C. Morrow, who collected the type specimen in an expedition in Peru in July and August, 1937. As a result of that expedition, a total of 319 specimens belonging to 106 species were sent to Henry W. Fowler at the Academy of Natural Sciences of Philadelphia, who described 22 species and five genera as new, including Liosomadoras morrowi .

Figures

Fig. 11. Liosomadoras morrowi: (a) holotype, ANSP 68646, 76 mm SL, río Ucayali basin, Contamana, Peru (photo by K. Luckenbill); (b) INPA uncatalogued, 45.8 mm SL, rio Jutaí (3°51’39.5’’S 67°34’45.9’’W), Amazonas, Brazil; (c) UF 117251, 95.2 mm SL, río Nanay, Loreto, Peru.