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Re: Spinosaurus Question




Christopher Taylor wrote:

or is this potentially an _Altispinax_/_Vulcanodon_-type
situation where the name is based on a feature not demonstrable in
the actual type material?

Also _Amygdalodon_. The teeth (only one of which could be located) were removed from the hypodigm by Rauhut.


Rauhut, O., (2003). Revision of _Amygdalodon patagonicus_ Cabrera, 1947 (Dinosauria, Sauropoda). Mitteilungen aus dem Museum fuer Naturkunde in Berlin: Geowissenschaftliche Reihe 6: 173-181.

As for _Altispinax_, the situation may be more complicated. According to Rauhut (2000), Huene explicitly attached the name _Altispinax _ to the tall-spined dorsals. Under this interpretation, _Megalosaurus dunkeri_ and _Altispinax_ have separate types, and _Becklespinax_ is a junior synonym of _Altispinax_.

In Rauhut's own words...

<< However, Huene (1926a: pp. 482-483) stated: "There is another specimen from the Wealden of Battle...consisting of three articulated middle dorsal vertebrae, with extremely high neural spines. ...if it were certain that such dorsal vertebrae belong to _Megalosaurus dunkeri_, it would be necessary to put it into a distinct genus, for which the name _Altispinax_, gen. nov., might be reserved.", and in 1932 (p. 235): "Three articulated dorsal vertebrae with very elongated neural spines, figured by Owen (202, Pl. 19), also seem to belong here; ...In 1926 ..., I based the genus _Altispinax_ on these specimens." (my translation). From this it is clear firstly that the generic name _Altispinax_ was proposed for the three vertebrae, and secondly does not refer to the nomen dubium _Megalosaurus dunkeri_. Since Huene (1926) did not propose a new specific name, the first available species name given exclusively to the vertebrae is Paul's (1988a) _Acrocanthosaurus altispinax_, the species thus becomes _Altispinax altispinax_ (Paul, 1988a). _Becklespinax_ Olshevsky, 1991, is thus an objective junior synonym of _Altispinax_ Huene, 1923. >>

I have to say that I kind of agree with Rauhut's 'take' on the entire _Altispinax_ thing. If true, _Altispinax_ is not a nomen dubium but the valid name of Wealden theropod represented by BMNH R1828 (three articulated tall-spined dorsal vertebrae).

Cheers

Tim

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