Astyanax argentatus Baird & Girard, 1854
Texan tetra

Family:  Characidae (Characins; tetras), subfamily: Stethaprioninae
Max. size:  11.43 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater
Distribution:  North America: USA and northern Mexico.
Diagnosis:  Dorsal soft rays (total): 10-10; Anal soft rays: 19-23; Vertebrae: 32-33. This species is distinguished from other Astyanax species in central-northern Mexico by the following characters: A 19-23, mode 20 (21-25, mode 23, in A. mexicanus, 18-20, mode 18, in A. rioverde); modally 7 scale-rows between lateral line and dorsal-fin origin (modally 8 in A. mexicanus, A. acatlanensis); nuptial spines or tubercles, just on anal-fin rays, all simple (just on pelvic fins in A. rioverde, and at least some bifid in A. mexicanus, A. acatlanensis); body more slender than A. mexicanus, A. rioverde, mean 34% SL (vs mean 37% SL); anterior fontanel, sharp-tipped (blunt in A. mexicanus); infraorbital IV, rectangular, with no projections (square, with projections in A. acatlanensis, A. mexicanus, A. tehuacanensis); ventral side of ceratohyal, straight (vs undulate). Posterior edge of interopercle, without a spine (with a spine in A. mexicanus, A. tehuacanensis); postcleithrum caudad process concave-sided (straight in A. mexicanus); largest hypuric plate, rostral border straight (concave in A. mexicanus) (Ref. 118583).
Biology: 
IUCN Red List Status: Least Concern (LC); Date assessed: 08 September 2018 Ref. (130435)
Threat to humans:  harmless


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