Glanidium botocudo, Sarmento-Soares & Martins-Pinheiro, 2013

Sarmento-Soares, Luisa Maria & Martins-Pinheiro, Ronaldo Fernando, 2013, Glanidium botocudo, a new species from the rio Doce and rio Mucuri, Minas Gerais, Brazil (Siluriformes: Auchenipteridae) with comments on taxonomic position of Glanidium bockmanni Sarmento-Soares & Buckup, Neotropical Ichthyology 11 (2), pp. 265-274 : 267-271

Glanidium botocudo , new species Fig. 1

Holotype. MNRJ 32538 , 93.0 mm SL, Brazil, Minas Gerais State, Nanuque, rio Mucuri, downstream from Santa Clara Dam , approximately 17 o 53’28”S 40 o 12’58”W, Nov 1997, P. S. Pompeu & A. L. Godinho.

Paratypes. All from Brazil, Minas Gerais. DZUFMG 47, 1, 95.0 mm SL, collected with the holotype. DZUFMG 48, 1, 83.0 mm SL and MNRJ 32539 , 1 , CS, 82.0 mm SL, Ponte Nova, rio Doce basin, rio Piranga , on area of influence of Baú I Dam, 20°17’07”S 42°55’13”W, Mar 1998, F. Vieira & P. S. Pompeu. DZUFMG 49, 1, 89.0 mm SL, limit between Dores de Guanhães and Braúnas, rio Doce basin, rio Santo Antônio drainage, rio Guanhães at Salto Grande Reservoir, 19°06’17”S 42°47’13”W, Jan 1999, F. Vieira & P. S. Pompeu. MBML 2047, 2, R, 86.8- 95.5 mm SL, Santa Cruz do Escalvado , rio Doce on area of influence of Baú I Dam, 20°15’24”S 42°54’56”W, Mar 1998, F. Vieira & P. S. Pompeu. MNRJ 31460 , 2 , 83.0-91.0 mm SL, córrego Joanésia, tributary of rio Santo Antônio , Joanésia, near limits with Açucena, downstream from Porto Estrela Reservoir , rio Doce basin, 19°07’48.6”S 42°39’21.2”W, 2-6 Dec 2004, R. E. S. Hojo .

Diagnosis. Glanidium botocudo is distinguished from its congeners, except G. albescens , by having small dark spots over a pale yellow ground color (vs. large dark blotches over a pale brown ground color). The new species differs from G. albescens by proportions of pectoral fin spine length, about 21-26 % in SL (vs. 17-20% in SL), by rib count 10 (vs. 9) and vertebral count 36-37 (vs. 38-39). Glanidium botocudo is distinguished from G. cesarpintoi , G. albescens , G. leopardum , G. melanopterum , G. catharinensis , and G. ribeiroi by having 36 or 37 (n = 5) vertebrae (vs. 38 or 39 in G. cesarpintoi (n = 2), 38 or 39 in G. albescens (n = 3), 40 or 41 in G. leopardum (n = 2), 41 in G. melanopterum (n = 5), 41 in G. catharinensis (n = 2), and 44 in G. ribeiroi (n = 2). The new species is also distinguished by having the anterior margin of the pectoral-fin spine with serrae on its entire margin (vs. serrae restricted to distal portion of spine in G. melanopterum , G. catharinensis and G. ribeiroi or smooth anterior margin in G. leopardum ) and by a long sharpened ventral process on urohyal (vs. distinctly short robust process in G. melanopterum , G. cesarpintoi , G. catharinensis , and G. ribeiroi ).

Description. Morphometric data in Table 1. Body short, head slightly depressed dorso-ventrally. Head robust, outline of head in dorsal view somewhat elliptic, longer than broad. Trunk from dorsal-fin base to caudal peduncle gradually compressed. Lateral profile of head from snout tip to opercular margin slightly convex until pectoral-fin insertion. Ventral profile of head and abdomen almost straight. Ventral profile of body gently curved, concave behind anal-fin origin. Head integument thick, cranial roof not visible; well-developed adipose eye lid; eye latero-dorsally located in anterior portion of head; mouth terminal, upper lip extended postero-laterally as well-developed fleshy rictal fold; snout margin rounded, in dorsal view; anterior nostril tubular, located on anterior border of snout; posterior nostril somewhat larger, rounded, limited by small skin flap; transverse distance between anterior nostrils proportionally shorter than distance between posterior ones. Maxillary barbel short, extending slightly beyond membranous border of opercle, reaching posterior cleithral process base; mental barbels short, tip not reaching pectoral-fin base, arranged in arc along ventral surface of jaw; inner mental barbel about 56.2-71.0% length of outer mentals. Posterior process of cleithrum short almost reaching vertical through origin of dorsal fin. Caudal peduncle moderately deep, depth about 10.4-12.7% SL.

Rostral border of cranium with mesethmoid longer than broad ( Fig. 2, me); premaxilla underneath with synchondral articulation; elliptical cranial fontanel, with two narrow openings: anterior one between mesethmoid and frontals and posterior one limited to frontals. Fontanel apertures separated from each other by suture beneath frontal, along orbitosphenoid. Nasal ossified, tubular, with narrow medial flanges, not sutured to mesethmoid. Autopalatine as flattened tube, oriented obliquely to longitudinal axis of body. Maxilla about half size of autopalatine. Prevomer developed, with expanded arrow-shaped lateral processes, Jaws of equal size; premaxilla and dentary narrow with four or five rows of robust conical teeth. First nuchal plate irregularly shaped, somewhat ellipsoid ( Fig. 2, n 1); second nuchal plate slightly concave along lateral margins ( Fig. 2, n2); third nuchal plate thin, projected laterally, with prominent tip ( Fig. 2, n 3). Epioccipital process very small ( Fig. 2, pe).

Hyomandibula broad, projected anteriorly ( Fig. 3, hy), connected to both quadrate and metapterygoid through cartilage and deep dentate suture. Metapterygoid conical, aswide lamina ( Fig. 3, mt), joined to quadrate via dentate suture. Quadrate trapezoidal, with broad base ( Fig. 3, qu), connected to preopercle, hyomandibula and metapterygoid; long preopercle ( Fig. 3, po) ventral margins sutured to both quadrate and hyomandibula; suprapreopercle present as short canal bone ( Fig. 3, sp); opercle laminate, ornamented and broadly subtriangular ( Fig. 3, op).

Hyoid arch with urohyal reduced with long sharpened ventral process ( Fig. 4, up); short dorsal hypohyal ( Fig. 4, dh) associated with comparatively large ventral hypohyal ( Fig. 4, vh); anterior ceratohyal well developed ( Fig. 4, ac), posterior ceratohyal smaller ( Fig. 4, pc); branchiostegal ray articulated to ceratohyals; branchiostegal rays 6; 4 on anterior ceratohyal, 1 associated with interceratohyal cartilage and posteriormost flattened, associated to posterior ceratohyal.

Branchial (gill) arches with urohyal, anterior to basibranchial 2; basibranchial 2 forming osseous rod, broadest anteriorly; basibranchial 3 shorter; basibranchial 4 large, flattened and cartilaginous; basibranchial 2 bordered laterally by cartilaginous head of hypobranchial 1; basibranchial 3 between cartilaginous head of hypobranchial 2 and cartilaginous hypobranchial 3; basibranchial 4 bordered laterally by cartilaginous head of ceratobranchial 4 and caudally by cartilaginous head of ceratobranchial 5. Hypobranchial 1 tubular, and hypobranchial 2 subtriangular, mostly osseous, elongate and expanded laterally, with cartilaginous lateral and medial ends; hypobranchial 3 completely cartilaginous, trapezoidal; hypobranchial 4 absent. Five ceratobranchials, mostly ossified, cartilaginous on both ends. First and second ceratobranchials supporting single row of rakers; third and fourth ceratobranchials with two rows of rakers; fifth ceratobranchial supporting single row of rakers, expanded postero-medially to support lower pharyngeal toothplate with short conical teeth. Five epibranchials, all but fifth largely ossified except for cartilaginous ends, suporting one or two rakers each, close to articulation with ceratobranchials. Epibranchials 1 and 2 rod-like; epibranchial 3 with posterior uncinate process; epibranchial 4 with laminar extension; epibranchial 5 cartilaginous, reduced, located on angle between cartilaginous ends of epibranchial 4 and ceratobranchial 4. Pharyngobranchial 1 and 2 absent; accessory cartilage between anteromedial cartilaginous tips of epibranchials 1 and 2; pharyngobranchial 3 elongate, ossified, with expanded posterior border; pharyngobranchial 4 ossified. Upper pharyngeal tooth plate with conical teeth, supported by pharyngobranchial 3 and 4, and also epibranchials 3 and 4.

Infraorbital 1 with ventro-lateral process clearly restricted to anterior border of eye. Subsequent four infraorbitals thin and tubular, in complete infraorbital series. Lateral line on body straight, inconspicuous, with ossified canal bones only anteriorly, unbranched at caudal fin.

Dorsal fin II,5, dorsal-fin spine with minute serrations along entire anterior margin, posterior margin with minute serrations on distal tip only. Pectoral fin I,5, pectoral-fin spine with 14- 19 antrorse serrations along entire anterior margin; 13-17 retrorse serrations along posterior margin; serrations on anterior margin smaller than posterior. Pelvic-fin i,5, margin rounded. Adipose fin small, origin at vertical through anal-fin base. Anal fin iii,8; anal-fin pterygiophores in nine rod-like proximal radials and eight cartilaginous distal radials. Caudal fin deeply forked, lobes with rounded tips, 8+9 principal rays, 16 upper procurrent, 15 lower procurrent rays.

Ribs 10 attached to consecutive vertebrae, becoming progressively smaller posteriorly. Total vertebrae 36 or 37 (n = 5).

Color in alcohol. Dorsal surface of head, body, scattered with small dark-brown chromatophores with depigmented area around adipose fin. Ground color gradually becoming lighter towards ventral parts. Dorsal fin dark brown on its base, becoming pale yellow towards tip. Paired, anal and adipose fins unpigmented. Caudal-fin rays with small dark brown spots.

Sexual dimorphism. Female specimens with a small intumescent genital papilla; with genital and urinary apertures separate. The male genital papilla is formed by a thick skin flap around a short emergent deferent duct. Male anal fin is strongly modified, with a pointed tip formed by the enlarged and thickened third unbranched and first branched rays. First unbranched anal-fin ray proportionally short, relative to subsequent fin-rays (Fig. 5, ui). The second unbranched anal-fin ray of males is elongated and intermediate in size between first and third anal-fin rays (Fig. 5, uii). The third unbranched anal-fin ray of males is about twice the length of first unbranched ray (Fig. 5, uiii). The male third unbranched anal-fin ray has a larger number of segments (26-29) relative to females (17-19). Posterior branched anal-fin rays of males are progressively shorter with last ray being the smallest (Fig. 5, b8).

Distribution. Glanidium botocudo was recorded from large coastal river systems, such as the rios Doce and Mucuri ( Fig. 6). It is the first record of the genus for the Eastern Atlantic river system (sensu CNRH, 2003) and also for Coastal Tablelands of the Barreiras Group. Coastal tablelands correspond to a region of mild relief, with elevations usually not passing 150 m, coinciding with the Cenozoic sediments of the Barreiras Group, well seen along the border between Espírito Santo and southern Bahia. Regarding global biogeographic regionalization of freshwater systems, the new species distribution pattern belongs to Northeastern Mata Atlantica ecoregion (sensu Abell et al., 2008).

Ecological notes. Glanidium species are nocturnal catfishes that inhabit lotic sections of rivers, and also lakes, in segments with riparian vegetation (F. Vieira, pers. comm.). Glanidium botocudo feeds on allochthonous resources, as beetles, and autochthonous aquatic invertebrates, such as insect larvae and gastropods, as evidenced by the examination of gut contents (MNRJ 32539, 82.0 mm SL).

Fig. 5. Male modified anal fin of Glanidium botocudo, MNRJ 32539, paratype, 82.0 mm SL. Left side lateral view. Abbreviations: b1, branched first ray; b8, branched eighth ray; dd, deferent duct; ui, unbranched first ray; uii, unbranched second ray; uiii, unbranched third ray. Scale bar = 1.0 mm.

Etymology. The specific name is a reference to the Botocudo, the generic name given to native indigenous people wearing artifacts (“botoques”) on ears and lips. Those Indians were the original inhabitants of large extensions of the Floresta Atlântica ( Paraíso, 1992), including the lands along the rio Mucuri valley and far west, to the rio Doce, range of the new Glanidium species. A noun in apposition.