Even more difficult to identify to the species level are the several species of Ray teeth found here. Order Myliobatiformes Family Myliobatidae (Eagle Rays) Isolated Myliobatis teeth are easily our most common fossil ray find in the creeks. There are a multitude of named species, but given the general lack of scientific research on fossil ray dentition it is hard to say how many are truly distinct. The genus is often a catch-all name for any kind of grinding ray teeth found; though Rhinoptera, or cow-nosed ray, teeth are also found here, having a thicker tooth surface, fewer nutrient grooves on the roots, and no angle where the roots meet the tooth. Aetobatus teeth are found alongside both these species and like Myliobatis, their teeth are large, flat and arranged in serried, tongue shaped rows creating a continuous surface for crushing and grinding food. These teeth are almost always found singly rather than complete sets or plates. Some sources claim the slanted angle of the teeth becomes less acute the more recent the species. The major distinction between Aetobatus and other 2 genus are the single rows on each plate, thus having closed or rounded ends on each tooth section as illustrated below; and a more acute angle of root to tooth. It is next to impossible to distinguish individual species in these 3 genus unless one finds a near complete plate. Many tail spine fragments are also found here. Order Pristioformes (Sawfirsh) Very rarely do we find a rostral (the spines on the saw) tooth of Pristis species, easily confused with a bone fragment. A long triangle in shape, a definate groove runs alongside one edge of good examples, which can be several inches long. Order Rajiformes Family Rhynchobatidae (Extinct Skates) By using a fine mesh screen several tiny teeth few millimeters in size have been found, the most common being Rhynchobatus. Family Dasyatidae (Stingrays) I have found some Dasyatis teeth, which are somewhat rarer than Rhynchobatus, having more delicate hook shaped roots and more angular tooth surface. Family Rajidae (Manta Rays) One of the rarest finds while sifting are Raja teeth, very similar to the previous 2 species, but with a pointed cusp and flattened roots. |
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Rays |
Fossil Teeth, Dermal Denticles and Tail Barbs of Batomorphii |