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Crow (Squalicorax pristodontus)
Age – Late Cretaceous; Commonality – common; Size – average: ¾ inches, max: up to a little over an inch (in our area)
The teeth of the crow sharks vary in shape more than any other species present here. Their teeth are flattened and normally have a greater width than length (in laterals). Crow shark teeth are also the only serrated type of shark tooth found here other than Pseudocorax. The ratio between tooth length and width gets smaller as you go further back into their mouth. They sort of don’t have an “anterior tooth” or “lateral position” or “posterior position”, such as in Scapanorhynchus teeth. It is just the tooth angle along with a couple other features that change. Anterior teeth have more of a straight shape, and posteriors are more curved distally. Crow teeth also sometimes possess small foramina on the labial side of the root. They have a cutting type of dentition.
Quotations are placed around “kaupi” because it is a paleobucket term which includes more than one species. It will likely be very difficult to determine how many “kaupi” species there really are.
The two types of Squalicorax teeth present are S. pristodontus and S. “kaupi“. S. pristodontus teeth are larger and have a wider angle in the notch on the distal part of the tooth. It also seems like S. “kaupi” is more variable than S. pristodontus.
S. “kaupi” had symphyseal teeth. The anteriormost teeth of S. “kaupi” resemble its symphyseal teeth. The symphyseals are rare and were likely disappearing from its dentition. Since their symphyseal teeth are rare, it is likely that not every S. “kaupi” individual had a symphyseal tooth file in their mouth. The symphyseal teeth are rather strange in appearance. They have a much narrower root than the usual crow teeth and can vary in shape. (Information from Steve B.)
S. pristodontus had fewer variations in tooth shape than S. “kaupi“. This likely has to do with the fact that it had fewer teeth in its jaws (the less teeth, the greater the chance they look similar to each other) than S. “kaupi“; it also has to do with the fact that “kaupi” is a paleobucket (the more species, the more variation). S. “kaupi” had a slightly smaller body size, but S. “kaupi” teeth are not smaller solely because of that reason; its jaws were only slightly smaller than that of S. pristodontus, but it had smaller teeth also because it had a higher tooth count. Both species have simplex serrations. S. pristodontus likely did not have a symphyseal tooth file.