Lepidocharax diamantina, Ferreira & Menezes & Quagio-Grassioto, 2011

Ferreira, Katiane M., Menezes, Naércio A. & Quagio-Grassioto, Irani, 2011, A new genus and two new species of Stevardiinae (Characiformes: Characidae) with a hypothesis on their relationships based on morphological and histological data, Neotropical Ichthyology 9 (2), pp. 281-298 : 283-285

Lepidocharax diamantina , new species Figs. 2-5

Holotype. MNRJ 37509 , 38.8 mm SL, male, Brazil, Bahia, Palmeiras, rio Santo Antônio, a tributary to rio Paraguaçu , approx. 12º31’S 41º34’W, 12 Mar 1999, A. Clistenes.

Paratypes. MNRJ 21997 , 55 , 19.8-38.2 mm SL (20, 25.1-38.9 mm SL), (1 c&s, 34.7 mm SL), collected with holotype; MZUSP 106499, 9, 33.3-37.8 mm SL, Brazil, Bahia, Iraquara, rio Pratinha, at fazenda Pratinha , 12º21’13”S 41º32’51”W, 17-21 Dec 1998, P. Gerhard, F. C. T. Lima, F. Di Dário & L. S. Rocha .

Diagnosis. Lepidocharax diamantina can be distinguished from Lepidocharax burnsi by having the head less deep (16.7- 18.8 vs. 18.7-25.0% SL), by having more longitudinal scale rows between the lateral-line and the pelvic-fin origin (8 vs. 6- 7); more lateral-line scales (47-56 [54] vs. 39-46 [41]); and less branched anal-fin rays (19-22 [22] vs. 21-26 [23]).

Description. Morphometric and meristic data for holotype and paratypes presented in Table 1.

Body laterally compressed, moderately elongate, largest specimen 38.8 mm SL. Greatest body depth situated at dorsalfin origin. Dorsal profile of head slightly convex from margin of upper lip to tip of supraoccipital spine; slightly convex from tip of supraoccipital spine to dorsal-fin origin; straight along dorsal-fin base; straight from posterior terminus of dorsal-fin base to adipose-fin insertion, and slightly concave from latter point to caudal-fin origin. Ventral profile of body convex from tip of lower jaw to anal-fin insertion and slightly concave ventral to caudal peduncle; anal-fin base straight.

Dorsal-fin rays ii,8*(25) or 9(4). Length of first unbranched dorsal-fin ray less than one-half length of second unbranched ray. Adipose fin present, its origin located vertically above bases of last three anal-fin rays. Pectoral-fin rays i,9*(18) or 10(11),i. Pelvic-fin rays i,5,i*(29).Anal fin with four unbranched rays followed by 19(1), 20(10), 21(6)* or 22(12) branched rays. Sexually mature males with hooks on anal-and pelvic-fin rays. Anal-fin hooks very small and located on segments from largest unbranched to 10 th branched ray ( Fig. 3 ). Usually, 10- 13 hooks per ray. Pelvic-fin hooks also numerous and small, and present on segments of all branched rays. Caudal-fin forked; lobes similar in size. Principal caudal-fin rays i,17,i*(29).

Premaxilla extending slightly anterior of vertical through tip of dentary. Premaxilla with two rows of teeth ( Fig. 4 ). Outer tooth row aligned in gentle arch, with 3(3), 4*(24) or 5(2) tricuspid teeth, with median cusps largest. Inner premaxillary tooth row with 4(21) or 5*(8) teeth. Symphyseal tooth in row with four cusps and remaining teeth with five cusps. Maxilla with 2*(3), 3(21) or 4(3) tricuspid teeth with median cusps slightly more developed. Dentary with four large anterior teeth with five cusps followed by smaller teeth with three to five cusps.

Scales cycloid.Lateral line complete, with 48(1), 49(2), 50(2), 51(2), 52(4), 53(4), 54*(6), 55(3), or 56(3) perforated scales. Eight longitudinal rows of scales between dorsal-fin origin and lateral line, 4*(17) or 5(12) between lateral line and pelvic- fin origin. Predorsal scales 19(4), 20*(8), 21(8), or 22(8). Circumpeduncular scales 15-21. Single row of five to seven scales extending along anal-fin base. Basal portion of both caudal-fin lobes covered by medium size scales, about same size as those present on caudal peduncle ( Fig. 5 ).

First gill arch with 10(3), 11(15), or 12*(8) gill rakers on hypobranchial and ceratobranchial, 6(23) or 7*(6) rakers on epibranchial and 1*(23) raker on cartilage between ceratobranchial and epibranchial.

Color in alcohol. Head and body of specimens retaining guanine on scales, therefore somewhat silvery. Overall ground coloration yellowish tan. Dorsal surface of head and lips with dense concentration of dark chromatophores. Scattered dark chromatophores covering only upper region of opercle, in fourth to sixth infraorbitals. Dark chromatophores concentrated on predorsal scales. Concentration of chromatophores decreasing progressively from middorsal region to lateral line, where limited to edges of scales. Chromatophores absent in scales of abdominal region below lateral line. Chromatophores present between lateral line and anal fin. Midlateral stripe on body extending from behind upper part of opercle to caudal peduncle. Dorsal, pectoral, pelvic, and caudal fins hyaline, with scattered dark chromatophores outlining rays and forming straight lines. Dark chromatophores concentrated along distal borders of interradial membranes of anal-fin base.Adipose fin pale, with small, dark chromatophores concentrated on posterior base of fin.

Distribution. Lepidocharax diamantina is known from the rio Paraguaçu basin, an independent costal river system in Bahia State, northeastern Brazil ( Fig. 6).

Etymology. Named after the Chapada Diamantina, the region where the species is found. Iraquara and Palmeiras where Lepidocharax diamantina was sampled are two of the 24 villages located in Chapada Diamantina.A noun in apposition.

Figures

Fig. 2. Lepidocharax diamantina, holotype, male, MNRJ 37509, 38.8 mm SL: Brazil, Bahia, Palmeiras, rio Santo Antônio.

Fig. 3. Hooks on anal-fin rays of Lepidocharax diamantina, MNRJ 21997, paratypes, 38.0 mm SL, adult male.

Fig. 4. Lepidocharax diamantina, MNRJ 21997, paratypes, 38.0 mm SL. Upper and lower jaws, left side, lateral view. Scale bar = 1 mm.

Fig. 5. Lepidocharax diamantina, MNRJ 21997, paratypes, male, 32.3 mm SL. Caudal-fin squamation, lateral view, left side.