Moenkhausia plumbea, Sousa & Netto-Ferreira & Birindelli, 2010

Moenkhausia plumbea View in CoL , new species

Figs. 6-9 View Fig View Fig View Fig View Fig

Holotype. MZUSP 99415 ( 49.5 mm SL), Brazil, Pará, Novo Progresso, tributary to rio Braço Norte , at bridge of BR 163 road near Air Force Base , rio Peixoto de Azevedo , rio Teles Pires drainage , rio Tapajós basin ; 09º17’59”S 54º50’00”W, 22 Jan 2009; A. L. Netto-Ferreira, J. L. Birindelli, L. M. Sousa & P. Hollanda-Carvalho. GoogleMaps

Paratypes. All from Brazil, Pará, Novo Progresso. ANSP 188911 About ANSP ( 5, 35.1-44.8 mm SL), GoogleMaps AUM 50664 (5, 34.3-41.2 mm SL), GoogleMaps INPA 33765 ( 5, 35.5-43.7 mm SL), GoogleMaps MCP 44510 (5, 32.8-44.2 mm SL), GoogleMaps MNRJ 35384 (5, 37.7-46.3 mm SL), GoogleMaps MPEG 18328 View Materials . (5, 32.3-40.9 mm SL), GoogleMaps MZUSP 96849 View Materials ( 14, 34.0- 51.2 mm SL, 2 c&s, 39.1, 42.0 mm SL), tributary of rio Braço Norte , rio Peixoto de Azevedo , rio Teles Pires basin , rio Tapajós drainage , 09º19’17”S 54º50’26”W, 10 Nov 2007, J. L. Birindelli, L. M. Sousa, A. L. Netto-Ferreira, M. H. Sabaj Pérez & N. K. Lujan. GoogleMaps MZUSP 101435 View Materials (24, 20.4-45.9 mm SL), same locality as ANSP 188911, 22 Jan 2009, A. L. Netto-Ferreira, J. L. Birindelli, L. M. Sousa & P. Hollanda-Carvalho. GoogleMaps MZUSP 101436 ( 1, 15.6 mm SL), tributary of rio Braço Norte , at bridge of BR 163 road, near the Air Force Base , rio Peixoto de Azevedo , rio Teles Pires basin , rio Tapajós drainage , 09º21’55”S 54º50’00”W, 22 Jan 2009, A. L. Netto-Ferreira, J. L. Birindelli, L. M.Sousa & P.Hollanda-Carvalho. GoogleMaps MZUSP 101439 (10, 30.1-49.3 mm SL), collected with holotype. GoogleMaps

Diagnosis. Moenkhausia plumbea is distinguished from all congeners, except M. chlorophthalma and M. petymbuaba , by the presence of large dark blotches on the anterior to the central portions of each scale along the seven dorsalmost longitudinal series ( vs. pigmentation absent or, when present, concentrated posteriorly along the border of scales and forming a reticulate pattern in the body). Moenkhausia plumbea differs from both M. petymbuaba and M. chlorophthalma in possessing a dark longitudinal stripe along the eye; and is further separated from M. petymbuaba in lacking a very conspicuous dark midlateral stripe; and from M. chlorophthalma in possessing eight or nine longitudinal rows of large dark blotches ( vs. seven), 33-36 lateral line scales ( vs. 25-28), five scales between lateral line and dorsal fin ( vs. four), 4-9 anal-fin base scales ( vs. 7-12), and usually 6 branched pelvic-fin rays ( vs. 7).

Description. Morphometric data presented in Table 2 View Table 2 . Overall size small (largest examined specimen 49.7 mm SL). Body compressed, moderately elongate. Greatest body depth located slightly anterior to dorsal-fin origin. Dorsal profile of head slightly convex from upper lip to vertical through nares; somewhat straight from latter point to tip of supraoccipital spine; convex from tip of supraoccipital spine to dorsal-fin origin, straight from dorsal fin terminus to adipose fin; slightly concave between latter point and origin of anteriormost dorsal procurrent caudal-fin ray. Ventral profile of head and body distinctly convex from lower lip to pelvic-fin origin; straight from latter point to anal-fin origin, and along anal-fin base; concave between terminus of anal-fin and anteriormost procurrent caudal-fin ray.

Mouth terminal.Terminus of maxilla located slightly posterior to vertical through anterior margin of orbit. Premaxillary teeth in two rows ( Fig. 8 View Fig ). Outer row with 5(2), relatively compressed, tricuspid teeth. Inner row with 5(2) robust pentacuspid teeth; Symphyseal tooth largest, slightly asymmetrical, with medialmost cusp greatly reduced. Maxilla with two tricuspid equally developed teeth. Dentary with 12(1) or 15(1) teeth; 4 or 5 anteriormost teeth larger, robust, pentacuspid, posterior ones conic, penta- or tricuspid, distinctly smaller. First gill arch with 2(2) hypobranchial, 8(2) ceratobranchial, 1(2) cartilage between ceratobranchial and epibranchial, and 6(2) epibranchial gill-rakers. Branchiostegal rays 4(2). Three rays originating on anterior ceratohyal and one on posterior ceratohyal.

Scales cycloid, circuli absent on exposed portion of scales, with few (usually up to 15) slightly divergent radii extending to posterior margin of scales. Lateral line slightly curved ventrally, completely pored, with 33(3), 34*(8), 35(11), 36(7) or 37(1) perforated scales. Horizontal scale rows between dorsal-fin origin and lateral line 5. Horizontal scale rows between lateral line and pelvic-fin insertion 4. Predorsal scales 9(5), 10*(24) or 11(1). Single row of 5*(7), 6(17), 7(4), 8(1) or 9(1) scales covering base of anteriormost anal-fin rays. Caudal peduncle with 14 circumpeduncular scales. Caudal fin scaled, scales present on proximal one-fifth of upper and lower caudalfin lobes.

Pectoral-fin rays i, 8(1), 9(13) 10*(15) or 11(1). Tip of pectoral fin almost reaching vertical through pelvic-fin origin. Pelvicfin rays i, 6*(32), 7(2). Supraneurals 4(1) or 5(1). Dorsal-fin rays ii (1) or iii (1), 7(1), 8(2) 9*(27), with first unbranched ray reduced in size. Dorsal-fin origin located slightly posterior to middle of standard length. Base of posteriormost dorsal-fin ray situated at vertical through anal-fin origin. First dorsal-fin pterygiophore inserted posterior to neural spine of 10 th vertebra (2). Adipose fin present. Anal-fin rays iii, 20(1); iv, 18(6); iv, 19(3); iv, 20(17); iv, 21(10); iv, 22*(2); v, 19(1) or v, 20(4). Anteriormost anal-fin pterygiophore inserted behind haemal spine of 17 th vertebra (2). Caudal fin forked, lobes slightly rounded and similar in size. Principal caudal-fin rays 10+9. Ten (2) dorsal procurrent and nine (2) ventral procurrent caudal-fin rays. Total vertebrae 35(1) or 36(1) with 17(2) precaudal and 18(1) or 19(1) caudal vertebrae.

Color in alcohol. Ground color tan, with chromatophores densely covering whole body, except for abdomen and along distinct unpigmented area extending from eye to caudal peduncle and forming light midlateral stripe. Lower lip, snout, top of head and dorsal portion of body densely covered by small dark chromatophores, resulting in overall countershaded color pattern. Margin of upper lip dark. Vertically elongate humeral blotch present but inconspicuous. Eight or nine dorsalmost longitudinal scale rows with scales bearing large dark blotches on anterior to central portions but fading towards scale margin. Broad, dark, slightly concave midlateral stripe extending from pectoral girdle to tip of median caudal-fin rays. Stripe diffuse, formed by scattered chromatophores. Dorsal, caudal, anal, and pectoral-fins hyaline, with small few chromatophores. Adipose fin dusky, with scattered small chromatophores ( Fig. 6 View Fig ).

Color in life. Ground color yellowish, with distinct clear midlateral yellow stripe and large, dark, ventrally curved longitudinal stripe immediately ventral to it. Stripes run from humeral region to caudal peduncle. Abdomen white to light yellow. Eye clear, with longitudinal dark stripe. Caudal fin with middle dark stripe delimited anteriorly by upper and lower yellowish areas. Specimens kept in captivity for several months have dorsal and anal fins lightly pigmented with gradients of green, yellow and red ( Fig. 7 View Fig ).

Etymology. From the Latin plumbum, meaning lead, in allusion to the color of the midlateral stripe below the unpigmented stripe in live specimens. An adjective.

Distribution. Known from headwaters of tributaries of the rio Braço Norte (rio Tapajós basin) in the Serra do Cachimbo ( Figs. 4 View Fig and 5 View Fig ).