Family Gymnuridae The Butterfly Rays

Presentation on theme: "Family Gymnuridae The Butterfly Rays"— Presentation transcript:

1 Family Gymnuridae The 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 Taxonomy 12-14 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

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

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

8 Found in the Atlantic, Pacific, and Indian Oceans
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 Mollusks Plankton Polychaetes
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 Population doubling time >14 years
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., Raies et autres batoides. p 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 Gymnura poecilura. In: IUCN IUCN Red List of Threatened Species. < Downloaded on 28 November 2007. Compagno, L.J.V., Checklist of living elasmobranchs. p 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 Gymnura micrura. In: IUCN IUCN Red List of Threatened Species. < Downloaded on 28 November 2007. Last, P.R. and J.D. Stevens, Sharks and rays of Australia. CSIRO, Australia. 513 p.  McEachran, J.D. and B. Seret, Gymnuridae. p 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 Fishes of the World, 4th ed. John Wiley and Sons, Inc, NJ. p 80. Smith, W.D. & Bizzarro, J.J Gymnura marmorata. In: IUCN IUCN Red List of Threatened Species. < Downloaded on 28 November 2007. White, W.T Aetoplatea zonura. In: IUCN IUCN Red List of Threatened Species. < Downloaded on 28 November 2007. Wintner, S.P Gymnura natalensis. In: IUCN IUCN Red List of Threatened Species. < Downloaded on 28 November 2007. Gonzalez-Isais, M and Domı´nguez, HMM Comparative Anatomy of the Superfamily Myliobatoidea (Chondrichthyes) With Some Comments on Phylogeny. JOURNAL OF MORPHOLOGY 262:517–535.