Naming the first mosasaur from Kansas
As a bit of historical background, the type
specimen of Tylosaurus proriger (MCZ 4374) was discovered
near Monument Rocks in Gove County by "Col. Connyngham and Mr. Minor,"and was
obtained by Professor Louis Agassiz during his 1868 visit to western Kansas. It was the
first mosasaur to be described from Kansas and was originally named Macrosaurus proriger by E. D. Cope. The
description of the new species by Cope (1869) in the
minutes of the Academy of Natural Sciences of Philadelphia meeting of June 1, 1869 was brief by modern standards:
He [Cope] made some remarks on a fine fragment of the muzzle of a
large Mosasauroid, which pertained to a cranium of near five feet in length. The pterygoid
bones were separated from each other, and support nine teeth. A peculiarity of physiognomy
was produced by the cylindric prolongation of the premaxillary bone beyond the teeth, and
a similar flat prolongation of the extremity of the dentary. He referred the species to Macrosaurus Owen, under the name M. proriger.
The following year, Cope
(1870, pl. 12, figs 22, 23) described the same specimen more completely, figured it
and, with little explanation, referred it to another European genus, Liodon Owen.
Two years later, O.C. Marsh, apparently recognising significant differences between the
American and European mosasaurs, proposed a new genus (Rhinosaurus: meaning nose-lizard) from a more
complete specimen (YPM 1268 - Rhinosaurus micromus) he had collected on the south side of the Smoky Hill
River in 1871. However, that name was preoccupied and Cope (1872) proposed
the genus name Rhamphosaurus. In a brief note, Marsh (1872b, p. 147) wrote that:
As this name [Rhinosaurus]
proves to be preoccupied, it may be replaced with Tylosaurus. The name Rhamphosaurus, since suggested by Prof. Cope,
cannot be retained, as it was given to a genus of lizards in 1843 by Fitzinger.
Leidy (1873, p. 274) was the first to place Macrosaurus
proriger Cope, 1869 into Tylosaurus Marsh.