Mazatlan Butterfly Ray: Gymnura crebripunctata

Family: Gymnuridae

Common names

Mazatlan Butterfly Ray, Longsnout Butterfly Ray.

Binomial

Gymnura crebripunctata

Synonyms

Pteroplatea crebripunctata, Pteroplatea rava.

Identification

A small butterfly ray with a wide, vaguely kite-shaped disc. Disc width approximately 1.6-1.9 x length. Pectoral fin apices angular. Snout short and broadly obtuse. Snout shorter and more rounded in females and juveniles, slightly longer and more angular in mature males.
Eyes very small. No tentacle present on posterior margins of spiracles. Spiracle has a deeply concave inner margin. Mouth arched with a convex symphysis on lower jaw.
Skin completely smooth. Tail short. Dorsal fin absent. Caudal sting absent.

Colour

Dorsum overall brownish-grey, pinkish-grey in juveniles. Usually with a pattern of very small, irregular, dark spots and paired larger diffuse dark blotches. Dorsum sometimes unmarked. Ventrum white with dark margin and pectoral fin tips. Tail subtly banded.

Size

Maximum disc width 81cm. Disc width at birth unknown.

Mazatlan Butterfly Ray, Gymnura crebripunctata. Aka Longsnout butterfly ray. Juvenile. Playa El Jobo, Costa Rica, Eastern Pacific.

Conservation Status

NEAR THREATENED

The Mazatlan Butterfly Ray (Gymnura crebripunctata) is captured in artisanal gillnets, beach seines, longlines, and trawl fisheries. Largely unregulated artisanal fishing pressure is intense throughout much of this species range.
It is estimated that the Mazatlan butterfly ray population has been reduced by 20-29% over the last 45 years.

Habitat

Tropical to warm-temperate water. On sandy or muddy substrates, often in shallow bays and estuaries, and on sandy slopes from intertidal to at least 30m.

Distribution

Eastern Pacific Ocean. Sea of Cortez, Mexico, to northern Peru.

Reproduction

Viviparous. Litter size unknown.

Diet

Diet unrecorded but probably feeds mostly on small fishes like other butterfly rays.

Behavior

Sedentary. Camouflages its body with sand by flapping its fins while resting on the bottom.

Reaction to divers

Fairly tolerant but will bolt if approached closely or if divers attempt to waft sand away from its disc.

Diving logistics

Relatively common in Guanacaste, Costa Rica. I have encountered this species in January in Playa El Jobo and Playa Del Coco. More common during the colder months from December to February.