Acestrocephalus pallidus Menezes, 2006
Acestrocephalus pallidus
photo by Menezes, N.A.

Family:  Characidae (Characins; tetras), subfamily: Characinae
Max. size:  6.05 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater
Distribution:  South America: known only from rio Madeira and rio Machado, a tributary of rio Madeira in Brazil.
Diagnosis:  Dorsal soft rays (total): 11-11; Anal soft rays: 36-40; Vertebrae: 38-39. Can be distinguished from Acestrocephalus boehlkei, Acestrocephalus maculosus and Acestrocephalus stigmatus by the absence of dark humeral blotch characteristic of these species. Differs from Acestrocephalus sardina and Acestrocephalus nigrifasciatus by having smaller eye and fewer maxillary teeth (30-38 vs. 40-46). Can be separated from Acestrocephalus acutus by possessing only scattered dark chromatophores instead of the typical oblong dark blotch on the caudal-fin base of that species and the first pleural rib, the cavity anterior to it and the obliquus inferioris muscle visible (vs. entirely covered by the fibers of the obliquus superioris muscle in Acestrocephalus acutus (Ref. 75890). Description: Dorsal fin ii,9; Anal fin iv,32-36; Pectoral fin i+11-15; Pelvic fin i+7 (Ref. 75890).
Biology: 
IUCN Red List Status: Least Concern (LC); Date assessed: 07 November 2018 Ref. (130435)
Threat to humans:  harmless


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