Acestrocephalus stigmatus
Acestrocephalus stigmatus Menezes, 2006
First described in: Menezes, N. A. (2006). Description of five new species of Acestrocephalus Eigenmann and redescription of A. sardina and A. boehlkei (Characiformes: Characidae). <em>Neotropical Ichthyology.</em> 4(4): 385-400.
Descriptions from checklists and floras indexed by GBIF
description
Description. Morphometrics of the holotype and additional specimens presented in Table 11. Meristic and morphometric data based on two lots from two widely separate localities, however no statistical differences were found between samples. Body moderately small (SL = 78.5 - 98 mm). Body form, dorsal and ventral body profiles, shape of snout and mouth and extension of maxilla as in A. sardina. Dorsal-fin rays ii, 9 in all specimens, n = 6, including holotype. Posterior most ray unbranched, n = 6. Adipose fin present. Anal-fin rays iv, 30 (unbranched rays iv, n = 6, branched rays mean = 30, range 29 - 31, n = 6, posterior ray split to its base and counted as 1). Moderately developed anterior anal-fin lobe including anterior unbranched rays and first 7 - 8 branched rays. Two sexually mature males (MNRJ 17610) with bilateral hooks on posterior anterior branched rays. One specimen (93 mm SL) has 10 hooks on second branched ray, 9 on third, 7 on fourth and 2 on fifth. Pectoral-fin rays i, 13 (anterior unbranched ray i, n = 6, branched rays mean = 13.3, range 13 - 14, n = 6). Posterior tips of longest pectoral-fin rays reaching to about one third of pelvic fin length. Pelvic-fin rays i, 7
Description of five new species of Acestrocephalus Eigenmann and redescription of A. sardina and A. boehlkei (Characiformes: Characidae)
diagnosis
Diagnosis. Acestrocephalus stigmatus can be distinguished from all congeners except A. boehlkei and A. maculosus by the presence of a dark humeral blotch. From A. boehlkei it differs in having fewer anal-fin rays (29 - 31 vs 34 - 36) and fewer scale rows around caudal peduncle (22 - 23 vs 25). It has more anal-fin rays (29 - 31) than A. maculosus (25 - 27). The muscular hiatus of the pseudotympanum in A. stigmatus (Fig. 5 d) is narrower than that of A. boehlkei, but much more developed than that of A. maculosus (Fig. 5 c).
Description of five new species of Acestrocephalus Eigenmann and redescription of A. sardina and A. boehlkei (Characiformes: Characidae)
discussion
Remarks. The two specimens from the rio Xingu drainage, not included in the type series did not show significant differences with respect to the type series, but additional specimens are needed for a more thorough evaluation.
Description of five new species of Acestrocephalus Eigenmann and redescription of A. sardina and A. boehlkei (Characiformes: Characidae)
distribution
Distribution. Specimens of this species are known from the rio Tocantins, rio das Mortes, a tributary of rio Araguaia (Fig. 8) and from the rio Xingu. It is sympatric with A. maculosus and A. acutus in the upper Tocantins basin.
Description of five new species of Acestrocephalus Eigenmann and redescription of A. sardina and A. boehlkei (Characiformes: Characidae)
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From the GBIF Backbone Taxonomy and occurrence records (GBIF.org), with Wikipedia and the Source Library. GBIF species 2353354.