Lebiasina yepezi, Netto-Ferreira & Oyakawa & Zuanon & Nolasco, 2011

Netto-Ferreira, André L., Oyakawa, Osvaldo T., Zuanon, Jansen & Nolasco, José C., 2011, Lebiasina yepezi, a new Lebiasininae (Characiformes: Lebiasinidae) from the Serra Parima-Tapirapecó mountains, Neotropical Ichthyology 9 (4), pp. 767-775 : 768-771

Lebiasina yepezi , new species

Fig. 1

Nannostomus or Pyrrhulina .- Géry, 1977: 588 [photography]. Lebiasina sp. - Géry & Zarske, 2002: 44-45 [comparison with

Derhamia hoffmannorum Géry & Zarske ].

Holotype. MNRJ 39067, 152.9 mm SL, Brazil, Amazonas State , upper rio Negro drainage, rio Marari , tributary of rio Padauari , at basecamp between 700 and 1000 m elev., upstream to Missão Marari of Ianomami Village, Serra Tapirapecó, 1°12’26”N 64°47’18”W, 12 Apr to 20 May 2004, U. Caramaschi & D. F. Moraes.

Paratypes. MNRJ 38917 , 24 , 23.7-123.5 mm SL (4, 97.5-123.5 mm SL), same data as holotype. Brazil. Roraima State, rio Branco drainage : INPA 15091 , 2 , 21.8-40.5 mm SL , MZUSP 62918 , 3 , 31.9-81.5 mm SL , MZUSP 81128 (1 c&s, 42.8 mm SL) Igarapé das Irmãs, rio Parima, tributary of rio Branco , 21 Sep 1998, Oncocercosis Team . INPA 15742 (1, 88.2 mm SL), rio Parima, tributary of rio Branco, Xitei-Xidea , 2°36’29”N 63°52’18”W, 17 Apr 1979, U. Barbosa (Oncocercosis Team) . INPA 15743 (9/18, 14.6-22.6 mm SL) , MZUSP 62917 (8, 12.0- 38.2 mm SL), Irmãs Xiteí , 9 Dec 1997, Oncocercosis Team . INPA 20518 (1, 93.6 mm SL) , MZUSP 81129 , 1 , 90.2 mm SL, rio Mucajaí, tributary of rio Branco, Yanomami’s indigenous area, Apr 2002, M. William . MPEG 1830 , 1 , 94.5 mm SL, Serra Parima, tributary of rio Uraricoera , 1200 m elev., Mar 1962, M. Hidasi [specimen examined by Géry, in Géry & Zarske, 2002: 45] . MZUSP 62916 , 1 , 96.5 mm SL, rio Parima, tributary of rio Branco, Xitei-Xidea , 2°36’29”N 63°52’18”W, 17 Apr 1979, U. Barbosa (Oncocercosis Team) . USNM 306560 , 3 , 21.8 -27.0 mm SL, río Parima, H. Axelrod, March 1963 [one specimen photographed and ilustrated in Géry, 1977: 588]. Venezuela. Amazonas State, rio Orinoco drainage : MAC-PAY 591 8, 37.1-134.9 mm SL (3, 90.6-134.9 mm SL), rio Niyayobä, Sierra Parima , 2°45’N 64°18’W, 17 Oct 1982, J. Fernández . MAC-PAY 619 , 3 , 27.3 -40.0 mm SL, Cañito Jopajewä, tributary of left margin of río Padamo, upstream of Coshilowäteri , tributary of right margin of rio Orinoco , 2º54’N 65º17’W, 22 Oct 1982, J. Fernández . MBUCV 11000 , 2 , 114.3 - 145.8 mm SL (1, 145. 8 mm SL), Atabapo, Caño Herita, río Ocamo , tributary of right margin of upper rio Orinoco , 3°45’N 64°35’W, Nov 1975, J. Lizot . MHNLS 4160 , 1, 106.7 mm SL, Mavaca, upper rio Orinoco, mouth of río Mavaca , 2º31’N 65º11’W, Nov 1981, J. Finkers . MHNLS 797 , 2 , 40.8-83.8 mm SL, Venezuela, Amazonas, Raudal Culebra 3º36’N 65º48’W, Dec 1951, A. Fernández-Yepez .

Diagnosis. Lebiasina yepezi is readily distinguished from all other members of Lebiasininae by the presence of a primary, secondary, tertiary, and intermediate stripes on the sides of the trunk ( Fig. 1 ; vs. primary and secondary stripes present in most Lebiasininae , except: L. astrigata (Regan) , L. aureogutatta (Fowler) , L. chocoensis Ardila-Rodríguez and L. multimaculata Boulenger , which present only the secondary stripe), and dorsal surface of the mesethmoid triangular shaped ( Fig. 2 ), without lateral projections (vs. mesethmoid T-shaped). Lebiasina yepezi further differs from its congeners (except L. taphorni Ardila-Rodríguez , L. unitaeniata (Günther) , L. uruyensis Fernandez-Yepez , and L. yuruaniensis Ardila-Rodríguez ) by the secondary stripe extending along scales of second and third longitudinal series (vs. stripe extending along scales of first and second longitudinal series), and caudal-fin blotch restricted to the caudal-fin median rays (vs. anterior margin of candal-fin blotch extending onto caudal peduncle). The new species also differ from its closest geographical relatives, L. yepezi differs from L. taphorni Ardila-Rodríguez , L. unitaeniata (Günther) , L. uruyensis , and L. yuruaniensis Ardila-Rodríguez by the extent of the intermediate stripe (from infraorbitals to anal-fin origin; vs. intermediate stripe restricted to infraorbitals 2 to 4).

Description. Morphometric data of Lebiasina yepezi are presented in Table 1. Body compressed and elongate. Dorsal profile of body distinctly convex from upper lip to vertical through nares, becoming slightly convex from that point to vertical through pectoral-fin origin, then nearly straight from latter to dorsal-fin origin; and slightly concave from that point to dorsal caudal-fin procurrent rays. Ventral profile of head and trunk convex from lower lip to pelvic-fin origin; straight from that point to anal-fin origin, convex at anal fin base, and concave from anal fin terminus to caudal-fin procurrent rays.

Mouth terminal. Premaxillary with single row of 9(1) or 11(1) tricuspid teeth decreasing in size posteriorly. Posterior tip of maxillary reaching distinctly beyond vertical through anterior margin of orbit. Maxillary with 5(1) or 7(1) tricuspid teeth. Dentary with two series of teeth. Outer series with 12(1) or 18(1) pedunculate tricuspid teeth with central cusp distinctly larger, teeth gradually decreasing in size posteriorly. Inner series with several minute conical teeth extending from the symphysis to coronoid process. Branchiostegal rays 4, 3 articulating with anterior-ceratohyal, and one with posteriorceratohyal.

Scales cycloid, circuli restricted to posterior border of scales, several radii (approx. 25) converging to center of scales and strongly anastomosed in the center, forming several cells. Lateral line longitudinal series with 26(1), 27(5), 28*(4), or 29(1) scales, of which only 3(3), 4(1), 5*(9), or 6(1) are perforated. Longitudinal rows of scales between dorsal and pelvic fins 7. Predorsal scales 12(7) or 13*(7). First longitudinal row of scales usually reaching vertical through dorsal-fin terminus, but may extend beyond that point by one or two scales. Circumpeduncular scales 12.

Pectoral fin with i,13(1), 14(4), 15*(5), or 16(2) rays. Pelvic fin i,7*. Supraneurals 10(8), anterior to neural spine of centra 5 to 14(8). Dorsal fin ii,8*(8) or 9(4) rays. First dorsal-fin pterygiophore inserted posterior to neural spine of centrum 14(8). Distal margin of extended dorsal fin rounded. Dorsalfin origin closer to caudal-fin origin than to tip of snout. Base of last dorsal-fin ray anterior to vertical through analfin origin. Anal fin iii,8*(9) or 11(1), last ray adnate. Distal border of extended anal fin rounded. First anal-fin pterygiophore inserted posterior to hemal spine of centrum 24(8). Adipose fin present. Caudal fin furcate, with upper lobe distinctly longer than lower lobe; both lobes rounded. Principal caudal-fin rays i,9/8,i. Dorsal procurrent rays 9(2); ventral procurrent rays 8(1) or 9(1). Precaudal vertebrae 23(2); caudal vertebrae 19(2).

Color in alcohol. Background color yellowish. Head densely pigmented from upper lip to origin of scales on the midposterior portion of parietals. Dark brown pigmentation extending from that point to caudal-fin insertion, through middorsal series of scales and immediately bordering scale rows. Infraorbital bones and opercular series with yellowish background color, with dark portions where primary, secondary and intermediate stripes extend across. Lower lip dark, densely pigmented. Ventral portion of head with minute scattered chromatophores.

Trunk dark dorsally, becoming lighter ventrally from third longitudinal series of scales. Abdominal area yellowish, lacking pigmentation between the isthmus and anal-fin origin. Mid-dorsal series with a black longitudinal stripe from back of head to dorsal-fin origin. Humeral blotch inconspicuous, round, overlapped by primary stripe. Four dark longitudinal stripes on the trunk. Primary stripe conspicuous, originating posterior to eye, extending across infraorbitals four and five, opercle and along trunk, to terminate at rear of caudal peduncle. Stripe subdivided starting at vertical through dorsal-fin terminus, into 10-12 small round blotches, overlying scales of fourth longitudinal series. Secondary stripe inconspicuous, extending from supracleithrum to middle rays of upper caudalfin lobe, over second and third longitudinal series of scales. Conspicuous intermediate stripe usually extending from mouth to vertical through anal-fin origin, onto scales of fifth longitudinal series, between primary and tertiary stripes. Tertiary stripe densely pigmented,except at proximal portion of caudal peduncle, extending from pectoral-fin origin to middle portion of caudal-fin lower lobe, onto scales of sixth longitudinal series. Caudal-fin blotch diffuse and rounded in juvenile specimens, located at basal portion of five median caudal-fin rays; caudal-fin blotch inconspicuous or absent in specimens longer than 123.0 mm SL, in which it may be represented by patches of chromatophores. Anterior border of caudal-fin blotch not extending onto caudal peduncle. Pelvic and dorsal fins hyaline, base of pectoral-fin rays densely pigmented, forming a round dark blotch. Anal fin lightly pigmented, grayish, with distal border hyaline. Base of last two anal-fin branched rays densely pigmented, forming an oblong dark blotch. Caudal-fin rays densely pigmented.

Sexual Dimorphism. Mature males of Lebiasina yepezi present the most common pattern of sex dimorphism among species of the genus: in which the anal-fin rays and anal-fin base are distinctly longer and thicker than females ( Fig. 3 ); hypertrophy of the inclinator muscles and the spiniform processes in which the muscles attach to the first lepidotrichia; scales of the fifth longitudinal series along the base of the anal fin modified (covered by a thin layer of a spongeous, apparently glandular, tissue); and breeding tubercles present on pectoral-, pelvic- and anal-fins rays, as well as on scales and sides of the head.

Distribution. Specimens of Lebiasina yepezi are known from rio Parima (rio Mucajaí system) and rio Uraricoera in the rio Branco drainage, rio Amazonas system, Roraima State, Brazil, the rio Marari (rio Padauari system) in the rio Negro drainage, rio Amazonas system, Amazonas State, Brazil, and the upper rio Orinoco drainage, upstream of La Esmeralda, Amazonas State, Venezuela ( Fig. 4 ).

Etymology. The specific name honors Agustín Fernández Yépez, first collector of the new species described herein.

Ecological notes. Lebiasina yepezi inhabits small and shaded forest streams, with fast-flowing clear water and a substrate consisting mainly of rocks and sand.

Figures

Fig. 1. Lebiasina yepezi: a) MNRJ 39067 holotype (152.9 mm SL), Brazil,Amazonas, rio Marari, tributary of rio Padauari, Serra Tapirapecó; b) MNRJ 38917, paratype (97.5 mm SL), same data as holotype.

Fig. 2. Anterior portion of the skull in dorsal view of: a) Lebiasina astrigata (MEPN 4418, 94.5 mm SL); b) Lebiasina yepezi. (MZUSP 81128, 42.8 mm SL), showing the usual T-shaped mesethmoid of Lebiasininae and the absence of lateral projections, respectively (FRO - frontal; LAT - lateral ethmoid; MES - mesethmoid; NAS - nasal; PRE - premaxillary).

Fig. 3. Anal-fin of Lebiasina yepezi evidencing the sexual dimorphism: a) Male (MNRJ 39067 - holotype) 152.9 mm SL; b) female (MNRJ 38917- paratype)97.5 mmSL.Arrow indicates breeding tubercles on the scales.

Fig. 4. Map of northern portion of South America with the distribution of Guyana Shield species of Lebiasininae: Lebiasina yepezi (stars), L. unitaeniata (diamonds), L. uruyensis (squares), L. taphorni (triangle) and L. yuruaniensis (circles). White polygons represent type-localities.