Characidium heirmostigmata , a new characidiin fish ( Characiformes : Crenuchidae ) from the upper rio Paraná basin , Brazil

Characidium heirmostigmata new species is described from the rio Ivaí drainage, upper rio Paraná basin, Paraná State, Brazil. The new species is diagnosed among its congeners by the possession of eight to 11 incomplete oblique dark bars on the body sides, extending upwards and downwards from the lateral line, independently of the eight or nine dorsal transverse bars usually present in species of Characidium. The new species is similar to Characidium serrano from the upper rio Uruguay basin, but differs by meristic and morphometric traits.


Material and Methods
Measurements and counts follow Buckup (1993c).Measurements were taken with digital calipers to the nearest 0.01 mm on the left side of the specimens and expressed as percents of Standard Length (SL) and Head Length (HL).Counts are described in the text, with the number of specimens for each count between parentheses, and the holotype data marked with an asterisk.Three paratypes of Characidium heirmostigmata were cleared and stained according to Taylor & Van Dyke (1985) procedures, in order to count vertebrae, ecto and mesopterygoid teeth, branchiostegal rays and ural bones, and for other osteologic observations.Cleared and stained specimens are represented by c&s.Institutional abbreviations follow standard ASIH codons listed at http://199.227.217.251/files/codons.pdf,with the addition of NUP (Coleção Ictiológica do Nupélia, Universidade Estadual de Maringá).Morphological data of C. borellii, C. etzeli, C. oiticicai, and C. pterostictum are based on literature accounts (Géry et al. 2001;Zarske & Géry, 2001;Melo, 2001;Buckup & Reis, 1997, respectively).
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.

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".Characidium is currently considered a monophyletic group based on one synapomorphy: a black spot near the base of middle caudal-fin rays (Buckup, 1993b).As Melo & Buckup (2002) stated, Characidium species have not been yet adequately classified into subgroups, but probably, Characidium heirmostigmata and C. serrano form a putative monophyletic group, uniquely diagnosed by the body side bars color pattern described above.

Discussion
For approximately forty years no Characidium species have been described from the upper rio Paraná basin.The discovery of the new species in the rio Ivaí drainage suggests that new efforts must be made for further collecting in the upper rio Paraná basin, mainly in its tributaries of the Paraná State.This fact is corroborated by Pavanelli (2006) in her recent description of Apareiodon vladii from the rio Piquiri basin.

Fig. 3 .
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 rio Abelha, all affluents of the rio Ivaí, upper rio Paraná basin.Symbols represent more than one lot of paratypes.