Orders Summary

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Order Summary for Rajiformes
Main Ref.:	Nelson, J.S., 1994
Order:	Rajiformes skates and rays
Class:	Elasmobranchii (sharks and rays)
Sister Order:	Torpediniformes 50 M years
Ref.:	Shirai, S., 1996
First fossil record:	early Tertiary middle Eocene
Occurs in:	Marine Freshwater Brackish
Remarks:	Gill openings ventral; anterior edge of the greatly enlarged pectoral fin attached to side of head, anterior to the gill openings; anal fin absent; eyes and spiracles on dorsal surface; anterior vertebrae fused to form a synarcual; suprascapulae of pectoral girdles joined dorsally over vertebral column and articulating with column of synarcual or fused with synarcual; nictitating membrane absent, cornea attached directly to skin around the eyes; body generally strongly depressed; jaws protrusible in most; teeth pavementlike; in most, water for breathing taken in chiefly through the spiracle rather than the mouth (except for those living off the bottom); most give birth to live young (some have eggs encased in a horny capsule); the snout may function as an electroreceptive organ (as may be true for all elasmobranchs).
Class etymology:	Greek eulanein, elasmos = metal beaten out + Greek brangchia = gills. Ref. 45335.
Order etymology:	Latin, raja = ray + Latin, forma = shape. Ref. 45335.
Families:	10 Anacanthobatidae , Dasyatidae , Gymnuridae , Hexatrygonidae , Hypnidae , Myliobatidae , Narkidae , Plesiobatidae , Potamotrygonidae , Rajidae , Rhinobatidae , Urolophidae , Urotrygonidae

*Ref.:*
	( e.g. 9948)

Page created by: Eli, 17.10.00, last modified by Eli, 15.02.05.