Family Gymnuridae The Butterfly Rays

1. Family GymnuridaeThe Butterfly Rays Greek, gymnos = naked + Greek,tai = tail

2. 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

3. Tooth Morphology

4. Order Myliobatiformes

5. 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 Taxonomy12-14 species in 2 genera

6. Gymnura debate G. marmorata G. afuerae G. crebripunctata Gulf of California to Peru

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

8. Distribution Found in the Atlantic, Pacific, and Indian Oceans

9. 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

10. Diet • Teleosts • Crustaceans • Benthic copepods, crabs, shrimps, prawns • Mollusks • Bivalves, cephalopods, gastropods • Plankton • Polychaetes

11. Predators • Marine mammals • Hammerhead sharks • Larger fishes

12. 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)

13. 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

14. Major Threats • Bycatch (shrimp trawlers) • Low recruitment/reproduction • High juvenile mortality • Habitat degradation and loss • Harvested for food • Food trade

15. 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.