Characidium heirmostigmata, da Graça & Pavanelli, 2008

da Graça, Weferson J. & Pavanelli, Carla S., 2008, Characidium heirmostigmata, a new characidiin fish (Characiformes: Crenuchidae) from the upper rio Paraná basin, Brazil, Neotropical Ichthyology 6 (1), pp. 53-53 : 53

Characidium heirmostigmata , new species

Figs. 1 and 2

Holotype. MZUSP 97738 , 35.0 mm SL, Brazil, Paraná, Município de Prudentópolis, upper rio Paraná basin, rio Barra Grande , tributary

54 Characidium heirmostigmata , a new characidiin fish

Paratypes. Brazil, Paraná, upper rio Paraná basin: MZUSP 97739 , 1 , 28.1 mm SL, collected with the holotype. MCP 41935, 3 , 38.8- 52.7 mm SL; MZUSP 97740 , 5 , 38.9-41.9 mm SL, NUP 1411 , 4 , 42.5-46.5 mm SL; NUP 5333 , 2 c&s, 38.9-44.6 mm SL: Município de Cândido de Abreu, rio Nestor, tributary to right margin of rio Ivaí , approx. 24°28’S 50°54’W, 22 Nov 1994, Nupélia. MNRJ 31594 , 8 , 44.2 -54.0 mm SL; NUP 1381 , 8 , 40.2-45.6 mm SL; NUP 1393 , 3 , 45.3 -50.0 mm SL; NUP 5334 , 1 c&s, 37.5 mm SL: Município de Jussara , rio Abelha , tributary to left margin of rio Ivaí , approx. 23°36’S 52°28’W, 17 Nov 1994, Nupélia .

Diagnosis. Characidium heirmostigmata can be distinguished from all other congeners, except C. serrano (upper rio Uruguai basin), by the presence of eight to 11 incomplete oblique bars on body sides, extending upwards and downwards from the lateral line and independent of the eight or nine dorsal transverse bars which usually are present in Characidium species. Characidium heirmostigmata differs from C. serrano by wider body width (12.2 to 15.7%) and shorter number of perforated scales on lateral line (32-35) vs 8.7 to 11.1% in SL, and 37-39 scales in C. serrano .

Description. Morphometric data summarized in Table 1. Body fusiform, moderately compressed. Dorsal profile convex between anterior tip of snout and dorsal-fin origin, except for small concavity due to inflexion of supraocciptal process, almost straight between bases of dorsal and caudal fins. Ventral profile convex, moderately arched between lower lip and posterior end of pelvic-fin base, straight between pelvic-fin base and anal-fin origin, and slightly concave between pel- vic-fin origin and caudal fin base. Greatest body depth at dorsal-fin origin.

Snout blunt and rounded, its tip at about same level as ventral margin of orbit. Mouth small and subterminal. Maxillary bone moderately elongated, reaching anterior margin of orbital. Orbit circular, slightly larger than snout length. Cheek smaller than orbit, its depth about one-third of orbit diameter.

W. J. da Graça & C. S. Pavanelli 55

Nares separated; posterior naris considerably closer to eye than to anterior naris; margin of anterior naris raised, forming circular rim; dermal flaps sometimes present in posterior naris. Supraorbital present, somewhat triangular in dorsal view, medial edge abutting frontal, anterior end narrow and directed away from frontal. Parietal branch of supraorbital canal absent. Parietal fontanel anteriorly limited by frontals. Branchiostegal rays 4(3); three attached to anterior ceratohyal and one to posterior ceratohyal. Orbitosphenoid slightly rectangular in lateral view, connected anteriorly to rhinosphenoid, posteriorly with pterosphenoid, with posterior-ventral free margin concave. Pterosphenoid foramen for ophthalmic nerve relatively small, formed by tunnel crossing pterosphenoid diagonally, bordered ventrally by bony crest, preventing direct lateral view of brain cavity through foramen. Gill-rakers 7(33*) on cerato and 4(33*) on epibranchial limb of first branchial arch.

Outer dentary teeth 8(33*), gradually decreasing in size, with three triangular cusps, occasionally with minute lateral cusp on medialmost teeth. Inner dentary teeth absent. Premaxillary teeth 6(4), 7(22*) or 8(7), all conic, posteriorly curved. Ectopterygoid teeth conic in single row 5(1), 6(1) or 8(1). Mesopterygoid teeth absent (3).

Scales cycloid; about 10-12 radii on posterior field of large scales. Small axillary scale present on pelvic-fin insertion, its tip extending about two or three scales posteriorly (33*). Lateral line complete 32(6), 33(6*), 34(19) or 35(2) perforated scales. Scale rows above lateral line 4(19) or 5(14*); and below 4(13) or 5(20*). Scales in predorsal series 12(33*). Scales around caudal peduncle 12(33*). Isthmus completely scaled.

Dorsal-fin rays iii,10(24*) or iii,11(9); pectoral-fin rays iii,10(26*) or iii,11(7); pelvic-fin rays i,8(20*) or i,9(13); analfin rays ii,8(14*) or ii,9(19); caudal-fin rays i,9,8,i(33*).All fins with posterior margin rounded, except bifurcate caudal fin. Adipose fin present.

Total number of vertebrae 34(3). Supraneurals between neural spine of fourth centrum and first dorsal-fin pterygiophore 4(3). Epurals 3(3). Uroneural present (3).

Color in alcohol. Background color of head and body pale yellow. Chromatophores distributed over entire surface of head, including cheek and gular area, more densely on dorsolateral region; diffuse, oblique, dark stripe extending from tip of snout to anterior margin of orbit, continuing longitudinally from posterior margin of orbit to preopercle. Dark humeral spot conspicuous and vertically elongate. Chromatophores near edge of exposed area of scales above lateral line forming reticulate pattern. Thin dark brown, longitudinal midlateral stripe accompanying lateral line, sometimes inconspicuous. Dark middorsal blotches 8(12*), 9(21). Vertical bars on body sides not corresponding in number or position to middorsal blotches; bars irregular, vertical or anteriorly tilted 8(10*), 10(12) or 11(11) extending down and backward from lateral line scales. Small, black spot near base of middle caudal-fin rays. Pectoral, pelvic, and anal fins hyaline. Dorsal fin with insconspicuous dark, transverse bands. Caudal fin with irregular vertical bands.

Sexual dimorphism. External sexual differences between males and females of Characidium heirmostigmata , such as coloration pattern or hooks on fins, were not found, even with the examination of breeding males and two living specimens.

Distribution. Known only from rio Abelha, rio Barra Grande, and rio Nestor, tributaries to rio Ivaí, upper rio Paraná basin, Paraná State, Brazil ( Fig. 3 ).

Etymology. From the Greek heirmos (series) plus stigmata (plural of stigma = marks), referring to the series of black marks present on the body sides. A noun in apposition.

Common name. Characidium heirmostigmata is popularly known in the sampled region as “canivete” or “mocinha”.

Figures

Fig. 1. Characidium heirmostigmata, holotype, MZUSP 97738, 35.0 mm SL. Picture horizontally flipped.

Fig. 2. Characidium heirmostigmata, paratype, NUP 1393, 40.8 mm SL.

Fig. 3. Partial map of Brazil and adjoining countries, showing the distribution of the new species. Triangle refers to the type-locality of Characidium heirmostigmata (rio Barra Grande), losangle demonstrates rio Nestor and dot indicates rioAbelha, all affluents of the rio Ivaí, upper rio Paraná basin. Symbols represent more than one lot of paratypes.