Microglanis carlae, Vera Alcaraz & da Graça & Shibatta, 2008

Vera Alcaraz, Héctor S., da Graça, Weferson J. & Shibatta, Oscar A., 2008, Microglanis carlae, a new species of bumblebee catfish (Siluriformes: Pseudopimelodidae) from the río Paraguay basin in Paraguay, Neotropical Ichthyology 6 (3), pp. 425-432 : 426-429

Microglanis carlae , new species

Figs. 1-2

Holotype. MNHNP 3667 , 32.5 mm SL, Paraguay, Ñeembucú, Mburika, arroyo Yacaré, left bank tributary of río Tebicuary , río Paraguay basin, 26°39’S 58°05’W, 30 Sep 2006, J. J. Resquín Centurión & M. del C. Paradeda.

Paratypes. All from Paraguay, río Paraguay basin. CZCEN 312 , 4 + 1 c&s, 25.2-33.6 mm SL , Cordillera, Nueva Colombia, río Salado , left bank tributary of río Paraguay, 25º09’S 57º22’W, Sep 1991, C. Dlouhy. CZCEN 313 , 6 + 1 c&s, 25.3-33.7 mm SL, Central, Limpio, río Salado , left bank tributary of río Paraguay, 25º06’S 57º28’W, 1994, C. Dlouhy. MNHNP 3668 , 5 , 15.5-29.1 mm SL, same locality data as holotype , 17 Nov 2006, H. S. Vera Alcaraz et al. MZUEL 5021 , 5 , 24.3 -30.0 mm SL; MZUSP 98255 , 5 , 25.0- 28.6 mm SL; NUP 5361, 4, 23.9-28.9 mm SL; NUP 5362, 1 c&s, 24.8 mm SL, same data as holotype .

Diagnosis. The following combination of characters distinguishes Microglanis carlae from its congeners: paired and anal fins mottled or with thin faint bands, trunk with darkbrown saddles, anterior margin of pectoral spine with serrations retrorse proximally and antrorse distally, tip of pectoral spine as a distinct bony point, continuous portion of lateral line reaching vertical through last dorsal-fin ray, caudal peduncle with irregularly shaped, faint to dark blotch, maxillary barbel surpassing vertical through dorsal-spine origin, and dark bar on posterior flank continuous from base of adipose fin to that of anal fin.

Microglanis carlae is further or specifically distinguished from M. ater , M. nigripinnis , and M. pellopterygius by having paired and anal fins mottled or with thin faint bands (vs. wide dark bands); from M. variegatus by having the trunk with dark-brown saddles (vs. mottled); from M. zonatus by having anterior margin of pectoral spine with serrations retrorse proximally and antrorse distally (vs. all retrorse except ultimate serration on one pectoral spine in holotype according to description and illustrations in Eigenmann & Allen, 1942: 89, pl. 3, figs. 1-2); from M. secundus by having the tip of pectoral spine as a distinct bony point (vs. tip of pectoral spine soft, not as distinct bony point, but implanted between two serrations, one straight, pointing outwards from anterior margin and the other curved, pointing backwards from posterior margin); from M. iheringi by having continuous portion of lateral line reaching vertical through last dorsal-fin ray (vs. reaching vertical through adipose-fin origin); from M. poecilus by having a caudal peduncle with irregularly shaped, faint to dark blotch (vs. triangular); from M. cibelae , M. cottoides , M. eurystoma , and M. malabarbai by the wider head, 91.6-108.1% of HL (vs. 60.2-70.1% in M. cibelae , 60.0-72.1% in M. cottoides , 50.9-71.8% in M. eurystoma , and 61.1-72.4% in M. malabarbai ), maxillary barbel surpassing vertical through dorsal-spine origin (vs. not reaching vertical through dorsalspine origin), and the dorsal lobe of caudal fin slightly longer than ventral lobe (vs. lobes equal in size); from M. parahybae by having 7 pleural ribs (vs. 6), and a dark bar on posterior flank continuous from base of adipose fin to that of anal fin (vs. not reaching blotch on base of anal fin); from M. garavelloi and M. leptostriatus by having a shallower caudal peduncle, depth 8.4-10.3% of SL (vs. 10.8-16.8% in M. garavelloi and 11.3-14.4% in M. leptostriatus ), dark bar on posterior flank continuous from base of adipose fin to that of anal fin (vs. not reaching blotch on base of anal fin), and by having caudal fin weakly forked (vs. emarginate). In addition, M. carlae differs from M. leptostriatus by the absence (vs. presence) of dark stripe along the axis of each gill filament, and differs from M. pataxo by having a wider head, 91.6- 108.1% of HL (vs. 58.2-64.7% in M. pataxo ), maxillary barbel surpassing vertical through dorsal-spine origin (vs. reaching pectoral-spine origin), and dark bar on posterior flank continuous from base of adipose fin to anal fin (vs. not reaching blotch on base of anal fin).

Description. Morphometric data summarized in Table 1. Head and anterior portion of body depressed, becoming laterally compressed from pectoral girdle towards caudal region. Greatest body depth at dorsal-fin origin (14.1-21.0% of SL), greatest body width at pectoral-fin base (25.1-30.6% of SL). Dorsal profile of head and anterior body straight or gently convex, ventral profile gently convex. Head approximately as wide as long (width 91.6-108.1% of HL), anterior margin broadly rounded in dorsal view. Eye small (orbital diameter 10.4-15.2% of HL), superior; orbital rim not free, covered by skin. Snout short (34.5-46.1% of HL), anterior nostril tubular, close to upper lip; posterior nostril with raised flap, close to eye. Mouth wide (55.5-72.3% of HL) and terminal.

Premaxillary tooth patch rounded laterally, without posteriorly projecting angle; teeth small and villiform. Dentary tooth patch semicircular, longer than premaxillary tooth patch. Barbels thin, flattened in cross section. One maxillary and two mental pairs of barbels. Maxillary barbel longest, surpassing vertical through dorsal-spine origin. Origins of mental barbels arranged in arc near anterior margin of lower jaw. Inner mental barbel one-half length of outer mental barbel. Outer mental barbel extending to pectoral-fin base. Lateral line incomplete, reaching vertical through posterior base of dorsal fin, with 5(2), 6(5), 7(2), 8(1), 9(5), 10(9), 11*(1), 12(1) pores. Lateral line followed by isolated neuromasts as far posteriorly as vertical through middle of adipose-fin base. Preopercular-mandibular branch of cephalic sensory canal system with 10 pores; four anteriormost pores associated with lower lip. Infraorbital and supraorbital branches of cephalic canal system bearing 4 and 5 pores, respectively. Branchiostegal membranes free from isthmus; branchiostegal rays 8(2), 9(1). Gill rakers filiform; 2,1,6(14), 2,1,7*(10), 2,1,8(1) on first arch.

Dorsal fin with one spinelet and I,6(27), margin rounded, entire base anterior to middle of standard length. Dorsal spine short, shorter than tallest dorsal-fin rays, with smooth anterior and posterior margins. Adipose fin elongated anteriorly and with free rounded margin posteriorly. Caudal fin weakly forked, dorsal lobe slightly more developed than ventral lobe; principal caudal-fin rays 11(2), 12*(25); dorsal procurrent rays 14(1); ventral procurrent rays 9(1). Pectoral fin I,5(27), triangular, adpressed tip not reaching base of pelvic fin. Anterior margin of pectoral spine with 7-9 retrorse serrations proximally followed by 2-10 antrorse serrations distally. Posterior margin of pectoral spine with 8(3), 9(11), or 10(10) strong retrorse serrations along entire length, larger than those along anterior margin ( Fig. 2). Posterior cleithral process slender and pointed posteriorly. Pelvic fin rounded with i,5(27) rays, adpressed tip not reaching anal-fin origin. Origin of pelvic fin vertically aligned with insertion of last dorsal-fin ray. Anal fin iii,6(2), iii,7*(21), iii,8(4), short and rounded, its base shorter than that of adipose fin and not confluent posteriorly with caudal fin; proximal radials 10(1), 11(2); distal radials 10(1), 11(1).

Post-Weberian vertebrae 28(2) or 30(1). Weberian complex with centra 1-5 fused, and ventrally open channel for aortic passage; transverse process 4 with anterior and posterior pointed processes; transverse process 5 pointed and shorter than preceding. Pleural ribs 7(3), becoming progressively smaller antero-posteriorly.

Color in alcohol. Head dark brown in dorsal view with two small yellowish blotches near posterior nares and small yellowish tan oblique blotch on posterior cheek extending ventroposteriorly from below eye. Large continuous transverse yellowish tan bar across occipital region between opercular openings. Barbels pale with brown spots. Body with dark brown saddles separated by yellowish tan interspaces. Anteriormost saddle in nuchal region (anterior to dorsal-spine origin), second below dorsal-fin base; first two saddles broadly confluent middorsally except for yellowish tan oval spot at origin of dorsal-fin spine, and confluent ventrally just above horizontal through pectoral-spine origin. Third dark brown saddle extending longitudinally from interdorsal region to middle of adipose-fin base, interrupted middorsally by tan oval patch over anterior base of adipose fin; saddle continuing ventrally as bar on posterior flank and usually reaching dark blotch on base of anal fin (bar faded below midlateral in five specimens). Broad, irregularly shaped dark brown blotch on caudal peduncle largely enclosing two small yellowish tan elliptical spots: middorsal spot located between vertical through posterior tip of adipose fin and base of caudal fin; midventral spot extends between posterior base of anal fin and base of caudal fin. Ventral surfaces of body and head pale yellow with very small tan to light brown spots and blotches.

All fins hyaline with brown spots or bands. Dorsal fin with dark brown base and broad dark brown submarginal band across fin spine, rays and membranes. Adipose fin with narrow dark brown blotch at center along base flanked anteriorly and posteriorly by yellowish tan blotches; distal margin pale. Pectoral fin with dark brown mottling on spine and middle portions of rays and membranes. Pelvic fin lightly speckled with small dark spots. Anal fin with dark blotch on bases of rays 3-7, and dark brown crescentic band on middle portions of rays and membranes. Caudal fin with dark brown (sometimes inconspicuous) vertical band continuous across middle portions of dorsal and ventral lobes.

Distribution. Known from the arroyo Yacaré, left bank tributary of río Tebicuary, and río Salado, left bank tributary of río Paraguay, río Paraguay basin, Paraguay ( Fig. 3).

Etymology. The specific name is in honor of Carla Simone Pavanelli (Universidade Estadual de Maringá, Núcleo de Pesquisas em Limnologia, Ictiologia e Aqüicultura) for her contributions to Neotropical Ichthyology.

Ecological notes. The stomach contents of two specimens included algae and insect larvae. Analysis of the reproductive condition in six specimens indicated adult males to be about 23 mm SL and females to be about 25 mm SL. One specimen was infected in the ventral region of the head by a parasite, the metacercaria stage of Digenea (Trematoda). Species found in moderately flowing sections of streams with dark brown water and bottoms of sand and mud; specimens collected with a dip net under floating vegetation at a depth of 1.5 to 2 m. The arroyo Yacaré ( Fig. 4, type locality) is a deep stream of dark brown water with patches of floating vegetation of Eichhornia sp. along the margins; riparian vegetation mainly grass for pasture with small patches of original shrubs, lianas and palm trees of Copernicia alba .