Astyanax taeniatus (Jenyns, 1842)
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Family:  Characidae (Characins), subfamily: Stethaprioninae
Max. size:  9.599 cm SL (male/unsexed)
Environment:  benthopelagic
Distribution:  South America: Macaé, São João, and Paraíba do Sul river basins in Rio de Janeiro State, and Benevente river basin in Espírito Santo State, Brazil. Specimens from Espírito Santo State are tentatively identified as A. taeniatus. Additional specimens are needed to further assess if the population from Epírito Santo State represents a distinct species.
Diagnosis:  Dorsal spines (total): 1-1; Dorsal soft rays (total): 10-11; Anal spines: 3-3; Anal soft rays: 21; Vertebrae: 37-37. Astyanax taeniatus is distinguished from all other species of the Astyanax by the presence of a gap between the symphyseal dentary teeth, with the exception of A. henseli. It differs from A. henseli by having only one humeral spot (vs. two), 19-23 anal-fin rays (vs. 22-27), orbital diameter 38.5-46, mean ¼ 42.2 (vs. 42.4-50.7, mean ¼ 46.7), and 12-13 gill rakers on hypobranchial (vs. 14-15). In addition, Astyanax taeniatus differs from A. henseli and most Astyanax species, except A. ribeirae, A. hastatus, A. giton, and A. bahiensis, by having a humeral spot shaped like a comma. It can be diagnosed from A. ribeirae and A. hastatus by having 38-41 scales on lateral line (vs. 34-36) and from A. giton and A. bahiensis by the format of third infraorbital (with a naked area in relation to preopercle vs. reaching preopercle, without naked area). It can be further diagnosed from morphologically similar species of the genus Astyanax that occur in Atlantic coastal river basins by having 38-41 perforated scales in the lateral line (vs. 34-38 in most of species), except A. aff. fasciatus, A. parahybae, and A. pelecus. It differs from A. aff. fasciatus, A. parahybae and A. scabripinnis by the dentary teeth decreasing abruptly after the fifth or sixth tooth (vs. dentary teeth decreasing abruptly after the fourth tooth). It can be differentiated from A. pelecus by humeral spot surpassing lateral line (vs. humeral spot restrict to the region above lateral line) (Ref. 119398). Teeth in the lower jaw 14 or more. The ventrals are exactly aligned with the origin of the dorsal fin.
Biology:  Occurs both in lotic and lentic water bodies associated with rocks and sand in the bottom. Stomach contents of 15 specimens ranging from 2.31 to 6.58 cm SL consisted predominantly of vegetal origin items (aquatic plants, filamentous algae) and in low proportion of aquatic insects (Chironomidae larvae and pupae, and Ephemeroptera). Individuals between 2.307 and 3.918 cm SL fed more on aquatic insects than algae; specimens ranging from 4.019 to 6.582 cm SL consumed more algae than aquatic insects; and the larger specimens measuring 5.37-6.582 cm SL fed exclusively on aquatic plants (Ref. 119398).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (123251)
Threat to humans:  harmless
Country info:   

Entered by: Luna, Susan M. - 03.04.95
Modified by: Torres, Armi G. - 25.01.19

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