Deinodon horridus, Leidy, 1856

Hay, OP, 1899, On the nomenclature of certain American fossil vertebrates, The American Geologist 24, pp. 345-349 : 346-347

In 1856 Dr. Leidy* described a new genus of dinosaurian reptiles from the Judith River beds of Montana, and this genus he called Deinodon ,

the single species being D. horridus . A more extended description with figures was published by Dr. Leidy in 1860.

When these descriptions were written Dr. Leidy was in doubt whether all the teeth comprehended under the name which he gave belonged to a single species or even a single genus. Some of the teeth, represented by figures 21 - 34, plate IX , as cited, resemble those of Megalosaurus and are broadly elliptical in section, with two denticulated carinae, on opposite sides of the crown. Other teeth, represented by figures 35 -45 , are somewhat U-shaped in section, with one nearly plane surface, corresponding to the top of the U, and this surface is bounded on each side by a denticulated carina. But none of these teeth was especially designated as types of the genus Deinodon .

In 1866 Prof. Cope‡ in considering these teeth, restricted the genus Deinodon (spelled Dinodon , however) to the teeth represented by figures 35-45 of Dr. Leidy`s plate .

The Megalosaurus-like teeth, represented by figures 21 - 34 , Prof. Cope regarded as belonging to his own genus Laelaps. In 1868 Dr. Leidy § again took up the subject; and refusing to be bound by Prof. Cope's action, he retained Deinodon (with the orthography Dinodon ) for the teeth of figures 21 -34 ; while for the others he proposed the new generic name Aublysodon , the species being called A. mirandus . In the same year Prof. Cope, ǁ replying to Dr. Leidy, defended his own procedure, but accepted Dr. Leidy’s generic name Aublysodon on the ground that “ Dinodon ” had been preoccupied by Duméril and Bibron for a genus of snakes.

Undoubtedly. Prof. Cope, being the first to distribute the materials of Dr. Leidy's composite species and genus, had entire right to assign the original name to such part thereof as he chose. and succeeding writers ought to have respected his work. Hence, Dr. Leidy’s original generic name adheres to the teeth represented by figures 35 -45 of his plate and not to the others. On the other hand, Prof. Cope erred when he undertook to improve Dr. Leidy’s name by writing Dinodon and again when, with this emendation as a basis, he accepted Aublysodon . Were Deinodon Leidy and Dinodon Duniéril and Bibrorı derived from the same Greek words, δεινος and 'οδων it would not be necessary first to emend Deinodon to Dinodon to produce interference But, while Leidys Deinodon is undoubtedly derived from the Greek words written above, Duméril and Bibron‘s Dinodon is not so derived. If we turn to the famous work on reptiles by the author* just mentioned, we find this explanation of their generic name: " Ce nom a été imagine par Bibron, d’apres l'examen de l'individu confié par M. Smith, Il semble composé de ∆t. par le milieu, de chaque côté, utrinque, et de Νοδως, édenté.”

This being the case, Dr. Leidy`s name. in its original form Deinodon , is not preoccupied and is the proper name to apply to those species which for many years have been arranged under the generic name Aublysodon .

It may be remarked here that more recently Prof. Cope† has emended also the Dinodon of Duméril and Bibron into Dianodon.

Figures

figures 21 - 34, plate IX

figures 35 -45