Arapaima agassizii (Valenciennes, 1847)

Family:  Arapaimidae (Bonytongues)
Max. size: 
Environment:  benthopelagic; freshwater
Distribution:  South America: known only from the holotype from Brazilian Amazon.
Diagnosis:  Can be diagnosed from its congeners by possessing the following characters: 44 dentary teeth, counted on single ramous only; 43 maxillary teeth; orbit diameter 1.5, relatively small compared to similar-sized individuals; interorbital width 4.1, relatively narrow; parietals with pronounced posterior projections that are pointed and curve slightly toward the midline; caudal fin widely separated from dorsal and anal fins by relatively long caudal peduncle, 9.7; caudal-peduncle length divided by peduncle depth 2.4; 26 anal-fin rays, with distinctly shorter basal length than that of dorsal fin; dorsal and anal fins extremely low in profile (dorsal-fin base divided by longest dorsal-fin ray about 7; longest dorsal-fin ray in anterior third of fin); and first pectoral-fin ray not (or only slightly) enlarged in diameter and with proximal tip similar in form to second and subsequent pectoral-fin rays. Can be further distinguished from Arapaima gigas by having single row of small teeth on dentary (vs. 2-2.5 rows of enlarged teeth in A. gigas ) (Ref. 93668).
Biology: 
IUCN Red List Status: Data deficient (DD); Date assessed: 31 July 2020 Ref. (130435)
Threat to humans:  harmless


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