Family GymnuridaeThe Butterfly Rays

Greek, gymnos = naked + Greek,tai = tail

Descriptive Features

• Skin relatively smooth with small denticles

• Broad, diamond shaped ray

• DW is almost 2x TL• Short tail • Some with poisonous

tail spine• Dorsal fin present or

absent

Tooth Morphology

Order Myliobatiformes

Taxonomy12-14 species in 2 genera

Aetoplata• A. zonura – Zonetail• A. tentaculata – Tentacled

Gymnura• G. australis - Australian• G. natalensis – Backwater• G. micrura – Smooth• G. altavela – Spiny• G. japonica – Japanese• G. poecilura – Long-tail• G. hirundo – Madiera (? validity)• G. bimaculata – Twin-spot• G. crooki• G. marmorata – California

– G. crebripunctata – Long snout– G. afuerae

G. marmorata G. afuerae

G. crebripunctata

Gymnura debate

Gulf of California to Peru

Largest Gymnura Gymnura altavela over 4m wingspan (>13ft)

DistributionFound in the Atlantic, Pacific, and Indian Oceans

Habitat

• Marine, rarely brackish• Tropical to temperate• Continental shelves• Demersal, benthic• Depths range from intertidal to100m • Prefers sandy and muddy substrates• Also found in brackish estuaries, hyper-saline

lagoons, coastal and neritic waters, bays, sandy beaches, and salt marshes

Diet

• Teleosts • Crustaceans

– Benthic copepods, crabs, shrimps, prawns

• Mollusks– Bivalves, cephalopods,

gastropods

• Plankton• Polychaetes

Predators

• Marine mammals• Hammerhead sharks• Larger fishes

Reproduction

• Two functional uteri• Aplacental viviparous• Embryos initially fed with yolk, then uterine milk• Gestation ~4-9 months• One reproductive cycle per year• Fecundity assumed to be <10• Females commonly abort fetuses upon capture

(G. poecilura)

Status

• IUCN status– 9 spp not in IUCN– 3 spp data deficient – 1 sp vulnerable –

A. zonura (declines of at least 30%)

– 1 sp near threatened – G. poecilura

• Population doubling time >14 years

Major Threats

• Bycatch (shrimp trawlers)

• Low recruitment/reproduction

• High juvenile mortality

• Habitat degradation and loss

• Harvested for food

• Food trade

Literature Cited• Bauchot, M.-L., 1987. Raies et autres batoides. p. 845-886. In W. Fischer, M.L. Bauchot and M.

Schneider (eds.) Fiches FAO d'identificationpour les besoins de la pêche. (rev. 1). Mèditerranée et mer Noire. Zone de pêche 37. Vol. II. Commission des Communautés Européennes and FAO, Rome. 

• Bizzarro, J.J. & White, W.T. 2006. Gymnura poecilura. In: IUCN 2007. 2007 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 28 November 2007.

• Compagno, L.J.V., 1999. Checklist of living elasmobranchs. p. 471-498. In W.C. Hamlett (ed.) Sharks, skates, and rays: the biology of elasmobranch fishes. John Hopkins University Press, Maryland. 

• Grubbs, R.D. & Ha, D.S. 2006. Gymnura micrura. In: IUCN 2007. 2007 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 28 November 2007.

• Last, P.R. and J.D. Stevens, 1994. Sharks and rays of Australia. CSIRO, Australia. 513 p. • McEachran, J.D. and B. Seret, 1990. Gymnuridae. p. 64-66. In J.C. Quero, J.C. Hureau, C. Karrer, A.

Post and L. Saldanha (eds.) Check-list of the fishes of the eastern tropical Atlantic (CLOFETA). JNICT, Lisbon; SEI, Paris; and UNESCO, Paris. Vol. 1. 

• Nelson, J.S. 2006. Fishes of the World, 4th ed. John Wiley and Sons, Inc, NJ. p 80.• Smith, W.D. & Bizzarro, J.J. 2006. Gymnura marmorata. In: IUCN 2007. 2007 IUCN Red List of

Threatened Species. <www.iucnredlist.org>. Downloaded on 28 November 2007.• White, W.T. 2006. Aetoplatea zonura. In: IUCN 2007. 2007 IUCN Red List of Threatened Species. <

www.iucnredlist.org>. Downloaded on 28 November 2007.• Wintner, S.P. 2006. Gymnura natalensis. In: IUCN 2007. 2007 IUCN Red List of Threatened Species. <

www.iucnredlist.org>. Downloaded on 28 November 2007.• Gonzalez-Isais, M and Domı´nguez, HMM. 2004. Comparative Anatomy of the Superfamily

Myliobatoidea (Chondrichthyes) With Some Comments on Phylogeny. JOURNAL OF MORPHOLOGY 262:517–535.