Cyprinodon arcuatus

Cyprinodon arcuatus (Santa Cruz pupfish) is a species of fish in the family Cyprinodontidae. It was endemic to the Santa Cruz River in Arizona. It was last seen in 1973 and was declared extinct in 2011.

Cyprinodon arcuatus
Conservation status
Extinct (2011)  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cyprinodontiformes
Family:	Cyprinodontidae
Genus:	Cyprinodon
Species:	†C. arcuatus
Binomial name
†Cyprinodon arcuatus Wendell L. Minckley & R. R. Miller, 2002

Description

The Santa Cruz pupfish exhibited sexual dimorphism in size, with males averaging 37mm (1.46in) in length and females averaging 32mm (1.26in) in length.^[2] Coloration in breeding males was dark green to black with alternating stripes of light and dark. Female and non-breeding males were reported to have clear fins except for a black dorsal fin. C. arcuatus is differentiated from other Cyprinodon species by a highly convex dorsal body and concave post-dorsal body, as well a lack of orange or yellow in breeding males' fins.