Dawson, Air-breathers of the Coal Period, p. 32, 1863.
Dawson, Acadian Geology, 3d ed., p. 368.
Dawson, Phil. Trans. Roy. Soc. London, pt. II, p. 643, pl. 44, figs. 131, 138, 139, 1882.
A smaller species than the preceding. The form ([plate 13]) is fully described by Dawson (Air-breathers of the Coal Period, p. 32, pl. IV, 1863) as follows:
"Among the reptilian remains found in erect trees at the South Joggins, there have occurred several portions of skeletons which, from their sculptural cranial bones, plicated teeth, and the forms of their scales and limb-bones, I have referred to the genus Dendrerpeton, but to individuals of much smaller size than the full-grown specimens of D. acadianum. It did not occur to me to suppose that these were specifically distinct from the larger individuals, until I observed that bones of this kind, contained in the collections sent by me to the Geological Society, or represented in the figures drawn to illustrate one of my papers, were referred by Professor Owen, in his notes on these specimens and figures, in the Journal of the Geological Society, to the genus Hylonomus; which is quite distinct from Dendrerpeton, as will be explained in sequel.
"I was thus induced to reexamine all the specimens in my collection and the result has been to establish a strong probability that there is in reality a second species of Dendrerpeton, smaller than D. acadianum, and differing from it in several points. This species I propose to name D. oweni. It differs from D. acadianum in the following particulars: (i) its much smaller size; ([2]) its long and hooked teeth (it will be seen that these teeth differ very markedly in their proportions and form from those of the larger species);([3]) the greater plication of the ivory in the intermaxillary teeth (in D. acadianum these teeth are, on the outside, simple almost to the base, and plicated on the inner side, while in this species they are plicated all around like the inner maxillary teeth);([4]) the form of the skull, which has the orbits larger in proportion, and is also shorter and broader. On the other hand, when we have described the species Hylonomus, it will be seen that this animal, except in size, differs from them quite as widely as does D. acadianum.
"The distinctness of D. oweni is further confirmed by the fact that I possess small jaw-bones of Dendrerpeton, about the size of those of this species, but having the teeth similar in form to those of the larger species; these I suppose to have belonged to young individuals.
"On examining the figures ([208, pl. IV]) it will be seen that the bones of the skull were corrugated as in the large Dendrerpeton, but with a smaller pattern. The forms of the jaw-bones also, and of the vertebræ, ribs, scapular bone, bones of the limbs, and bony scales, are very similar, and indicate that in general form this creature was not far removed from its larger relative. The bones of the foot especially deserve attention. This is the most perfect foot of Dendrerpeton hitherto found; and I have enlarged it in the figure ([208]) in order more distinctly to show its parts. It presents three long toes with traces of a smaller one at each side, so that there were probably five in all. If these toes be compared with the footprints on the slab discovered by Dr. Harding, it will be seen that they very closely correspond, though the toes of the present species are much smaller. The footprints are precisely those which we may suppose an animal of the size of Dendrerpeton acadianum would have made if, as the bones found render in every way probable, this larger species had a foot similar to that of D. oweni. I suppose, for this reason, that these footprints are really those of Dendrerpeton acadianum and that this species continued to exist from the time of the lower Coal Measures to the period when those higher beds of the series, in which its bones are found at the Joggins, were deposited.
"The present species must have lived in the same places with its larger relative, but may have differed somewhat in its habits. Its longer and sharper teeth may have been better suited for devouring worms, larvæ, or soft-skinned fishes, while those of the larger Dendrerpeton were better adapted to deal with the mailed ganoids of the period, or with those smaller reptiles which were more or less protected with bony or horny scales.
REMAINS OF SKIN AND HORNY SCALES.