Cope, E. D.
[Remarks on Holops brevispinus, Ornithotarsus immanis, and Macrosaurus proriger.]
Proceedings of the Academy of Natural Sciences of Philadelphia, 11(81):123
Meeting of June 1, 1869
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LEFT: A drawing of the muzzle of the type specimen of Tylosaurus proriger from Cope, 1870, pl. 12, figs. 22, 23.
The type specimen of Tylosaurus proriger (Harvard MCZ 4374) was discovered near Monument Rocks in Logan County by "Col. Connyngham and Mr. Minor," and was obtained by Professor Louis Agassiz during his 1868 visit to western Kansas (Cope, 1869; Williston, 1898; Russell, 1967). It was the first mosasaur to be described from Kansas and was originally named Macrosaurus proriger by Cope.
The recorded description of the new species by Cope (1869) at the June 1 meeting of the Academy of Natural Sciences of Philadelphia (ANSP) was brief by modern standards (below). The species name (Macrosaurus proriger) was referred to by Joseph Leidy in the Proceedings of the ANSP on January 4 and January 11, 1870.
Natural Sciences of Philadelphia 123
The President, Dr. Hays, in the Chair.
Twenty-one members present.
Prof. Cope exhibited some specimens of extinct reptiles of interest.
He 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 specimen he stated belonged to Prof. Agassiz, who obtained it from Western Kansas, probably from the No. 3 of the Upper Cretaceous [Niobrara Fm.] of Hayden.
The following year, Cope (1870, Pl. 12, fig. 22-23) described the Harvard specimen more completely, figured it (above) and, with little explanation, referred it to another European genus (Liodon Owen). Two years later, Marsh (1872), apparently recognizing significant differences between the American and European mosasaurs, proposed a new genus (Rhinosaurus nose lizard) from a more complete specimen (YPM 1268) he had collected near the Smoky Hill River. However, that name was preoccupied and Cope (1872) proposed the genus name Rhamphosaurus.
In a brief note, Marsh (1872b) 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.