  SUPPOSED MICROSAURIAN SPECIES OF UNCERTAIN RELATIONSHIP. The following three species are so unusual and so incompletely known that they can not be considered with any of the above families: Brachydectes newberryi Cope, Linton, Ohio; Amblyodon problematicum Dawson, Nova Scotia; Proterpeton gurleyi Moodie, Danville, Illinois. Cope, Proc. Phila. Acad. Nat. Sci., 1868, p. 214. Cope, Trans. Am. Phil. Soc., 1868, p. 14. Cope, Geol. Surv. Ohio, II, pt. II, p. 388, 1875, pl. xxvii, fig. 2. Type: Brachydectes newberryi Cope. Cope (Geol. Surv. Ohio, vol. II, pt. II, p. 388, 1875), says: "This genus is indicated by two rami of a mandible and a portion of a premaxillary only. These, when compared with those of Œstocephalus and Tuditanus, from the same locality, and with others described by authors, are so much stouter, i.e., shorter and more elevated, that they evidently belong to a genus unlike either. The genus further differs from Œstocephalus in having the teeth of equal size to the posterior part of the series; that is, to the base of the elevated coronoid process. The teeth are elongate cylindrical cones, with their acute tips turned a little posteriorly. The fractured ones display a large pulp cavity. The three premaxillaries preserved are similar, but without curvature at the tips. They do not exhibit striÆ or any other sculpture. "So far as the remains known go, the genus is nearer Hylerpeton than any other. According to Dawson, that genus is provided with a large canine-like tooth, at the anterior extremity of the maxillary, on the inner row, which is inserted into a distinct socket. No such tooth appears among those of this genus. The latter does not give any indication of the very elevated coronoid process of Brachydectes, though the external portion of the dentary bone in that region being lost, little can be said about it." Brachydectes newberryi Cope. Cope, Proc. Phila. Acad. Nat. Sci., p. 214, 1868. Cope, Trans. Am. Phil. Soc., 1868, p. 14. Cope, Geol. Surv. Ohio, II, pt. II, p. 388, pl. xxvii, fig. 2, 1875. Type: Specimen No. 8604 G, American Museum of Natural History. Horizon and locality: Linton Ohio, Coal Measures. Cope (Geol. Surv. Ohio, vol. II, pt II, p. 388, 1875) says of this form: "The species is represented by one nearly perfect ramus mandibuli, one dentary bone and one premaxillary, probably not complete. "The dentary bone appears to have been attached by suture to the articular and angular, as its free margin has very much of the outline of that suture in Amphiuma and lizards. The coronoid process would also seem to be a part of the same bone as in Amphiuma and Menopema, and not composed of the coronoid bone as in lizards. It rises immediately behind the last tooth, and displays no suture. "The lower portion of the dentary is prolonged into an acute angle. This is separated by a deep and wide concavity from the superior posterior prolongation, which is obtuse, and rises at once into the coronoid process. Teeth on this dentary, seven; the same number is on the preserved ramus; this number is suspected to be complete, or nearly so. The teeth terminate at the obvious termination of each ramus, which is, it is true, slightly obscured. These teeth are the longest in the Microsauria in relation to the depth of the ramus, equaling the largest in Œstocephalus. They are doubtless exposed, as are some of those of the last-named genus, by the splitting away of the outer parapet of the dentary bone. As no traces of alveoli have been thus rendered visible I suspect the dentition to have been acrodont, as in some existing Batrachia. "No external surface of the mandible remains, but there are no impressions of sculpture on the matrix. A little external face of the premaxillary displays none. "The species is dedicated to Professor John S. Newberry, the able director of the Geological Survey of Ohio, and discoverer of most of the Batrachia herein described."
Type: Proterpeton gurleyi Moodie. Known from a single vertebra. Spine very high and heavy, the neural canal large. Proterpeton gurleyi new species. Type: Specimen No. 13,296, Walker Museum, University of Chicago. Horizon and locality: Coal Measures near Danville, Illinois. The vertebra, as preserved, is well characterized by the figure (plate 22, fig. 2). The spine is high and heavy, the neural canal is large, and the centrum reduced. The form is very unusual. It is apparently from the cervical region, as there are no indications of zygapophyses, transverse processes, or hÆmal arches, although they may have been abraded; apparently not, however. The type specimen was discovered near Danville, Illinois, about the horizon of the Danville coal, so that it is quite high in the Allegheny series of the Pennsylvanian and of about the same horizon as the phalangeal bone from Breeze, Illinois, which may be provisionally associated with this form. There is no assurance that Proterpeton gurleyi is an amphibian. The vertebra may have belonged to a fish.
Dawson, Phil. Trans. Roy. Soc. London, pt. 11, p. 644, pl. 40, figs. 57-61, 1882. Type: Amblyodon problematicum Dawson. This genus was described by Dawson in 1882 from very imperfect remains. He says that it is "characterized by stout cylindrical teeth, blunt at the apices; but otherwise imperfectly known." Amblyodon problematicum Dawson. Dawson, Phil. Trans. Roy. Soc. London, pt. II, p. 644, pl. 40, figs. 57 to 61, 1882. Type: Specimen No. 3061-10, Peter Redpath Museum, McGill University. Fig. 38.—Skeletal elements of Amblyodon sp. from the Coal Measures of Nova Scotia. a, tooth, × 25; b, section of tooth, × 25; d, fragment of thoracic plate; f, shaft of limb bone; e, rib. Horizon and locality: Coal Measures of Nova Scotia. A fragment of a jaw 1 cm. in length has 10 cylindrical teeth, simple and smooth, with large pulp cavities and rounded regularly at the apices. With these are 4 vertebrÆ of the usual type, measuring together 1 cm. Fragments of cranial bones also occur and are obscurely pitted. There is also what seems to be the shaft of a limb bone and a few oval scales. A flat and somewhat rhombic bone, with a style at one side, may possibly be a thoracic plate or possibly a parasphenoid. The material is too scanty for any satisfactory description of this animal, but it is provisionally named Amblyodon problematicum. | ||||||||||||||||||||||||||||||||
|
