Bryconamericus pinnavittatus, Dagosta, Fernando C. P. & Netto-Ferreira, André L., 2015

Dagosta, Fernando C. P. & Netto-Ferreira, André L., 2015, New species of Bryconamericus Eigenmann (Characiformes: Characidae) from the rio Teles Pires, rio Tapajós basin, central Brazil, Zootaxa 3911 (3), pp. 433-442 : 434-437

Bryconamericus pinnavittatus , new species

Figure 1 ; Table 1

Holotype. MZUSP 115349, 27.4 mm SL, Brazil, Pará State, Jacareacanga Municipality, stream affluent of the right margin of the rio Teles Pires, downstream of Sete Quedas, 09°18’52’’S 56°46’54’’W, 15 Jan 2008, col. M.V. Loeb & A. de Castro.

Paratypes. All from Brazil, Pará State, Jacareacanga Municipality, rio Tapajós basin. MZUSP 98257, 2, 22.5–23.2 mm SL, same date as holotype. MZUSP 98282, 4, 21.4–24.0 mm SL; MPEG 30443, 3, 20.4–22.3 mm SL, right margin of rio Teles Pires, dowstream of Sete Quedas, 09°19’01’’S 56°46’46’’W, 15 Jan 2008, col. M.V. Loeb & A. de Castro. MZUSP 99568, 1, 21.6 mm SL, left margin of rio Teles Pires, 09°17’57’’S 56°47’32’’W, 23 Mar 2008, col. R. Hilário. MZUSP 99943, 6, 22.2–25.7 mm SL, 1 c&s, 24.3 mm SL, 1 M, 27.1 mm; MPEG 30444, 1 c&s, 25.2 mm SL, rio Teles Pires, upstream of Sete Quedas, 09°20’38’’S 56°46’42’’W, 10 Jun 2008, col. L.M. Sousa & A.L. Netto-Ferreira.

Diagnosis. Bryconamericus pinnavittatus differs from all congeners, except B. bolivianus Pearson , B. cismontanus Eigenmann , B. deuterodonoides Eigenmann , B. grosvenori Eigenmann , B. hyphesson Eigenmann , B. lambari Malabarba & Kindel , B. macrophthalmus Román- Valencia, B. ornaticeps Bizerril & Perez-Neto , B. patriciae da Silva, B. rubropictus (Berg) , B. tenuis Bizerril & Auraujo , and B. thomasi Fowler , by having 11–13 branched anal-fin rays (vs. 15 or more). The new species can be distinguished from B. bolivianus , B. deuterodonoides , B. grosvenori , B. hyphesson , B. lambari , B. ornaticeps , B. patriciae , B. rubropictus , B. tenuis , and B. thomasi by the presence of two maxillary teeth (vs. three or more), from B. cismontanus by the presence of four outer premaxillary teeth (vs. 5 or 6), and from B. macrophthalmus by the lower number of perforated lateralline scales (34–38 vs. 40–41).

Description. Morphometric data of holotype and 17 paratypes are given in Table 1 . Greatest body depth at vertical through dorsal-fin origin. Head pointed anteriorly in lateral view. Dorsal profile of head convex from tip of snout to vertical through posterior nostril, slightly convex from that point to distal tip of supraoccipital spine; body profile slightly convex from latter point to origin of dorsal fin, straight along dorsal-fin base, concave from dorsalfin base terminus to anteriormost dorsal caudal-fin procurrent ray. Ventral profile of head and body convex from tip of lower lip to pelvic-fin insertion, slightly concave from that point to anal-fin origin, straight along anal-fin base and concave from anal-fin terminus to anteriormost ventral caudal-fin procurrent ray.

Mouth subterminal, upper jaw longer than lower jaw. Premaxillary teeth in two rows. Outer row with 3(1), 4*(18), or 5(1) conical or tricuspid teeth. Inner row with 4*(20) tri- to pentacuspid teeth. Maxilla with 2*(20) tri- to pentacuspid teeth; anteriormost tooth largest. Medial dentary tooth pentacuspid, dentary with 4*(19) or 5(1) larger pentacuspid teeth, teeth decreasing in size from mesialmost tooth to lateral ones, followed by 2(2) minute conical or tricuspid teeth. First gill arch with 2(2) gill-rakers on hypobranchial, 6(2) on ceratobranchial, 1(2) on intermediate cartilage, and 4(2) on epibranchial. Branchiostegal rays 4(2).

Scales cycloid, circulii restricted to anterior, covered area of scales, with few (around 4-6) divergent radii extending to posterior margin of scales. Lateral line slightly curved ventrally, with 34(5), 35(4), 36(2), 37*(3) or 38(1) perforated scales. Longitudinal scale rows between dorsal-fin origin and lateral line 4(12) or 5*(6); longitudinal scale rows between lateral line and pelvic-fin origin 3*(18). Predorsal scales 11*(12) or 12(6). Circumpeduncular scales 12*(13). Single row of 4 to 6 elongate scales at the base of anal- fin rays.

Pectoral-fin rays i,11(8) or i,12*(10). Tip of pectoral fin not reaching vertical through pelvic-fin insertion. Pelvic-fin rays i,5,i(1) or i,6,i*(17). Tip of pelvic fin reaching vertical through anal-fin insertion. Rod-like shaped supraneurals 5(2), anterior to 5th(2) to 9th(2) vertebral centra. Dorsal-fin rays ii,8*(20). First dorsal-fin pterygiophore inserted behind neural spine of 10th(2) vertebral centrum. Distal margin of expanded dorsal fin slightly convex. Dorsal-fin base on middle of body; base terminus anterior to vertical through anal-fin origin. Analfin rays iii*(18); 11(4), 12*(11) or 13(3). Distal margin of anal fin concave. First anal-fin pterygiophore inserted posterior to haemal arch of 16th(2) vertebral centrum. Adipose fin present. Caudal fin forked, lobes approximately similar in size. Principal caudal-fin rays i,9/8,i*(20). Dorsal procurrent caudal-fin rays 12(2), ventral procurrent caudal-fin rays 11(2). Total vertebrae 35(2); precaudal vertebrae 16(2), caudal vertebrae 19(2).

Color in alcohol. Overall ground color pale yellowish ( Fig. 1 ). Infraorbital, opercular, and gular areas retaining intense guanine deposition in some specimens. Head dark, densely pigmented in dorsal view. Snout tip to nares with scattered chromatophores. Midline dorsal scales from posterior tip of supraoccipital to anteriormost dorsal caudal-fin procurrent ray bordered with dark chromatophores. Few sparse dark chromatophores on upper portion of opercle. Premaxilla and anterior half of maxilla with few scattered chromatophores. Vertically elongate humeral blotch, encompassing 2 scales horizontally and 3 vertically, including scales of lateral line series. Borders of humeral blotch diffuse. Body pigmented by scattered small dark chromatophores, more intense dorsal to midlateral septum. Dark chromatophores following the myosepta from vertical through middle of dorsal-fin to caudal peduncle. Dark chromatophores from middle portion of second unbranched ray to third branched ray and distal portion of remaining posterior dorsal-fin rays forming a diffuse band on dorsal fin. Diffuse dark band from middle portion of interadial membranes of first unbranched anal-fin ray to third branched ray extending to distal portion of remaining posterior rays. Pectoral, pelvic and adipose fins hyaline. Base of caudal-fin rays with intense concentration of dark cromatophores. Outermost caudal-fin rays with cromatophores along its entire length. Distal portion of all caudal-fin rays pigmented. Median caudal-fin rays lacking pigment on its middle portion, forming an unpigmented area and more evident on upper than on lower caudal-fin lobe.

Etymology. The specific name pinnavittatus , derives from the latin pinna (= fin) and vittatus (= adorned with a ribbon), referring to the pigmented vertical band present at the base of caudal-fin rays.

Sexual dimorphism. Pelvic-fin hooks were observed in one specimen (MZUSP 99943). Hooks were present on the middle portion of first to fourth innermost branched pelvic-fin rays.

Distribution. Bryconamericus pinnavittatus is only known from its type locality in the lower rio Teles Pires, rio Tapajós basin ( Fig. 2 ).

Figures

FIGURE 1. Bryconamericus pinnavittatus, all from Brazil, Pará, Jacareacanga, rio Teles Pires, rio Tapajós basin, (a) holotype, MZUSP 115349, 27.4 mm SL and (b) paratype, MZUSP 99943, 24.9 mm SL.

FIGURE 2. Type locality of Bryconamericus pinnavittatus in rio Teles Pires, rio Tapajós basin, Brazil. Red dot represents the holotype and the other collection events.

Tables

TABLE 1. Morphometric data for Bryconamericus pinnavittatus.

	n	Holotype	mean	range SD
Standard length (mm)	18	27.4	23.4	20.4 – 27.4
Percents of SL
Depth at dorsal–fin origin	18	20.1	20.5	19.0 – 22.0 1.0
Snout to dorsal–fin origin	18	51.8	52.6	51.1 – 54.7 1.0
Snout to pectoral–fin origin	18	25.2	25.4	21.8 – 26.6 1.0
Snout to pelvic–fin origin	18	49.3	49.8	44.7 – 52.3 2.0
Snout to anal–fin origin	18	65.7	65.6	59.8 – 67.9 2.0
Caudal peduncle depth	18	8.4	8.8	8.0 – 9.6 0.5
Caudal peduncle length	18	17.9	18.1	16.8 – 18.9 0.6
Pectoral–fin length	18	17.9	18.7	14.8 – 21.6 1.6
Pelvic–fin length	18	15.0	14.9	13.2 – 16.5 0.8
Pelvic–fin insertion to anal–fin origin	18	16.1	16.3	13.7 – 17.8 1.1
Dorsal–fin origin to anal–fin origin	18	23.7	23.9	21.6 – 26.9 1.2
Dorsal–fin origin to pelvic–fin insertion	18	20.6	20.7	18.9 – 22.1 1.0
Dorsal–fin origin to pectoral–fin insertion	18	32.1	32.6	27.8 – 34.9 1.7
Dorsal–fin length	18	23.9	24.3	22.4 – 26.4 1.0
Dorsal–fin base length	18	12.0	12.9	10.7 – 14.7 1.1
Anal–fin length	18	19.3	18.8	15.2 – 21.2 1.3
Anal–fin base length	18	18.3	18.6	16.8 – 20.0 0.9
Eye to dorsal–fin origin	18	40.2	37.6	35.4 – 40.2 1.2
Dorsal–fin origin to caudal–fin base	18	50.0	50.0	48.6 – 51.7 0.9
Head length	18	23.8	25.0	23.5 – 26.9 0.8
Percents of head length
Horizontal eye diameter	18	40.6	42.5	39.2 – 47.5 2.3
Snout length	18	25.1	25.2	22.2 – 27.4 1.5
Interorbital width	18	30.4	29.1	26.1 – 33.9 2.1
Upper jaw length	18	31.9	31.6	27.2 – 33.9 1.6