Hyphessobrycon wosiackii, Lima, 2017

Lima, Flávio C. T., 2017, Two new Hyphessobrycon (Characiformes: Characidae) species from Central Amazon basin, Brazil, Zootaxa 4318 (1), pp. 123-134 : 130-132

Hyphessobrycon wosiackii , new species

( Fig. 5 )

Holotype: MPEG 34741, 34.2 mm SL: Brazil, Pará, Juruti, headwaters of the Igarapé Juruti Grande (a tributary of Rio Amazonas), 2°34'36''S, 56°24'3''W; W.B. Wosiacki, 4 Aug 2004.

Paratypes: MPEG 7913, 20, 3 c&s, 22.2–34.5 mm SL; ANSP 203201, 5, 24.1–33.6 mm SL; ZUEC 14199, 5 , 23.3–33.7 mm SL: same data as holotype . MPEG 10343, 18, 20.1–30.8 mm SL; MNRJ 50065, 5 , 20.7–29.3 mm SL: same locality as holotype; W.B. Wosiacki & A. Bezerra, 5 Aug 2004.

Diagnosis. Hyphessobrycon wosiackii , new species, can be diagnosed from all its congeners, with the exception of H. amapaensis Zarske & Géry , H. ericae , new species, H. heterorhabdus (Ulrey) , and H. montagi Lima, Coutinho & Wosiacki, by presenting an humeral blotch continuous with midlateral stripe that becomes blurred posteriorly, not reaching beyond adipose fin (vs. humeral blotch, when present, not continuous with midlateral stripe, or stripe extending to caudal fin). It can be distinguished from the aforementioned species, except H. ericae and H. montagi , by presenting a caudal peduncle blotch (vs. caudal peduncle blotch absent). The new species is distinguished from H. ericae by humeral blotch roundish (vs. humeral blotch vertically elongated), and from H. montagi by presenting a single humeral blotch (vs. two connected humeral blotches).

Description. Morphometric data for the holotype and paratypes presented in Table 2. Body compressed, moderately short and deep. Greatest body depth situated slightly anterior to vertical through dorsal-fin origin. Dorsal profile of head convex from tip of upper jaw to vertical through anterior nostril; straight or slightly concave from that point to tip of supraoccipital spine. Dorsal profile of body convex from supraoccipital spine tip to base of last dorsal-fin ray, approximately straight from that point to adipose-fin insertion and slightly concave between adipose-fin insertion and origin of anterior most dorsal procurrent caudal-fin ray. Ventral profile of head and body convex from tip of dentary to anal-fin insertion. Body profile along anal-fin base straight and posterodorsally slanted. Ventral profile of caudal peduncle slightly concave.

Jaws equal, mouth terminal. Posterior terminus of maxilla reaching vertical through anterior third of eye. Maxilla approximately at 45 degree angle relative to longitudinal axis of body. Nostrils close to each other, anterior opening roughly oval, posterior opening roughly crescent-shaped. Nostrils separated by narrow flap of skin. Premaxillary teeth in two rows; outer teeth row with 2(1), 3*(30), or 4(2) uni- to tricuspidate teeth; inner teeth row with 5(33) or 6*(1) tri- to pentacuspidate teeth. Maxilla with 2(1), 3(1) or 5(1) uni- to tricuspidate teeth; anteriormost tooth usually largest. Dentary with 11(1), 13(1), or 15(1) teeth, anteriormost 4–5 teeth considerably larger, tri- to pentacuspidate, followed by smaller, conical teeth. Central cusp of all teeth more developed than remaining one; dentary cusp tips slightly curved inward, premaxillary cusp tips outwardly-curved.

Scales cycloid, moderately large, with 2 to 6 weakly marked radii; circuli strongly marked proximally. Lateral line slightly deflected downward and incompletely pored, with 6(5), 7(16), 8(6), 9(1), or 10*(2) perforated scales. Longitudinal scales series including lateral-line scales 31(6), 32(5), 33(5), 34(8), or 35*(3). Longitudinal scale rows between dorsal-fin origin and lateral line 5*(34). Longitudinal scale rows between lateral line and pelvic-fin origin 3*(34). Scales in median series between tip of supraoccipital spine and dorsal-fin origin 9(10) or 10*(24). Horizontal scale rows around caudal peduncle 10(8), 11(15), or 12*(11). Single row of 3–4 scales covering base of anteriormost anal-fin rays. Caudal fin with scales only basally.

Dorsal-fin rays ii, 9*(32), two specimens ii, 8; small ossification anterior to first unbranched ray present in all three c&s specimens. Dorsal-fin origin at middle of standard length. First dorsal-fin pterygiophore located behind neural spine of 9th (3) vertebrae. Adipose fin present. Anteriormost anal-fin pterygiophore inserting posterior to haemal spine of 15th (3) vertebrae. Anal-fin rays iv, 18(2), 19(6), 20*(19), or 21(7), last unbranched and 4–5 anteriormost branched rays slightly longer, subsequent rays gradually decreasing in size; distal margin of anal fin slightly concave, with distinctive anterior lobe. Pectoral-fin rays i, 9(10), 10(16) or 11*(8). Tip of pectoral fin reaching vertical at pelvic-fin insertion. Pelvic-fin rays i, 7* (32); two specimens (MPEG 7913, 27.8 mm SL and ZUEC 14199, 34.5 mm SL) missing entirely pelvic fins. Tip of pelvic fin reaching anal-fin insertion. Principal caudal-fin rays 10+9(3). Caudal fin forked, lobes somewhat pointed and of similar size. Eleven (2) or 12(1) dorsal procurrent caudal-fin rays and 8(2) or 9(1) ventral procurrent caudal-fin rays. Vertebrae 34(3). Supraneurals 4(3). First gill arch with 3(3) hypobranchial, 7(1) or 8(2) ceratobranchial, 1(3) on cartilage between ceratobranchial and epibranchial, and 4(1) or 5(2) epibranchial gill-rakers.

Color in alcohol. Overall ground coloration of head and body beige ( Fig. 5 ). Dorsal portion of head and body dark. Snout, tip of dentary, maxilla, antorbital and infraorbitals 1 and 2 with a dense concentration of small dark chromatophores, imparting an overall dark coloration. Infraorbitals 3–6, opercle and preopercle with scattered dark chromatophores. Uppermost three scale rows with pigmentation concentrated along edges, imparting an overall reticulate pattern, and clearly contrasting with clearer area situated immediately above midlateral muscle septum. Clear stripe parallel and immediately below dark dorsal area, extending from opercle to end of caudal peduncle. Humeral blotch very conspicuous, roughly square-shaped anteriorly, and developed as a short longitudinal stripe, extending along 5–6 scales, becoming blurred at its posterior portion. Abdominal region with scattered dark chromatophores. Area immediately above anal-fin basis with relatively numerous small dark chromatophores, imparting an overall dusky pattern. Caudal peduncle and caudal fin with a caudal peduncle blotch, slightly dislodged ventrally, with apex roughly triangular in shape towards head, continuing into middle caudal-fin as an elongate, roughly rectangular blotch. Small dark chromatophores scattered on interradial membranes of all fins, sometimes over rays of caudal and dorsal fins. Pelvic, dorsal and anal fins with dark chromatophores scattered along interradial membranes. Adipose fin with scattered dark chromatophores.

Sexual dimorphism. Not detected.

Distribution. Only known from the Igarapé Juruti Grande, a direct tributary of the Rio Amazonas, Pará state, near the border with Amazonas state, Brazil ( Fig. 3 ).

Ecological notes. The type-locality, the headwaters of the igarapé Juruti Grande, lies at a terra firme (non seasonally flooded) site. Gut contents of three c&s specimens contained algae and disarticulated arthropod remains.

Etymology. The specific epithet honors our friend and fellow ichthyologist Wolmar Benjamim Wosiacki, fish curator from the Museu Paraense Emílio Goeldi, in recognition to his important contributions to the knowledge of Brazilian fishes.

Figures

FIGURE 3. Map of central and eastern Amazon basin in Brazil, showing distribution of Hyphessobrycon ericae (red dots; red star indicates type-locality; orange dots indicate distribution of a distinctive color morph with elongated humeral blotch, see Text) and type-locality of H. wosiackii (purple pentagon).

FIGURE 5. Hyphessobrycon wosiackii, new species: a, holotype, MPEG 34741, 34.2 mm SL, Brazil, Pará, Igarapé Juruti Grande; b, paratype, MNRJ 50065, 28.8 mm SL, same locality.