  THE AISTOPODOUS MICROSAURIAN FAMILY PTYONIIDÆ, FROM THE COAL MEASURES OF OHIO. Family PTYONIIDÆ Cope, 1875. Cope, Geol. Surv. Ohio, II, pt. II, p. 357, 1875. Elongate, slender, weak-limbed, aquatic microsaurians. Neural and hÆmal spines of vertebrÆ elongated, expanded and sculptured. Ventral armature weakly developed or absent. Skull lanceolate, with long, slender teeth. Three genera are assigned to this family: Ptyonius, Œstocephalus, and Thyrsidium. The forms are very closely related, and when additional material is secured the three genera may be found to be identical. The species included in this family are: Ptyonius pectinatus Cope, P. vinchellianus Cope, P. marshii Cope, P. nummifer Cope, P. serrula Cope, Œstocephalus remex Cope, O. rectidens Cope, Thyrsidium fasciculare Cope. The species are all exclusively from the Linton, Ohio, Coal Measures, and most of them are known from abundant material. Cope, Geol. Surv. Ohio, II, pt. II, p. 373, 1875. Cope designated no species as the type, but we may regard Ptyonius pectinatus as typical. Form elongate, with long tail and lanceolate cranium. Limbs weak, a posterior pair only discovered. Three clavicular elements; abdomen protected by packed osseous rods, which are arranged en chevron, the angle directed forward. Neural and hÆmal spines of caudal vertebrÆ expanded and fan-like. Ribs well developed. The various species vary in length from 3 to 10 inches. They are the most abundant amphibian in the Linton beds. The present genus resembles Lepterpeton Huxley (334), of the Kilkenny, Ireland, Coal Measures. But that genus possesses divided abdominal rods, or "oat-shaped scales," and the form of the cranium and proportions of the body are different. The genus is closely related to, possibly identical with, Œstocephalus, but additional material will be required to settle this point. Cope (123) gives the following key for the separation of the 5 species:
Cope, Proc. Acad. Nat. Sci., 1868, p. 216. Cope, Trans. Am. Phil. Soc., XIV, p. 20, 1869. Cope, Trans. Am. Phil. Soc., XV, p. 266, 1874. Cope, Geol. Surv. Ohio, II, pt. II, p. 377, pl. xxvii, fig. 7; xxviii, figs. 2, 3, 6; pl. xxix, fig. 2; pl. xxx, fig. 2; pl. xxxv, figs. 1-3; pl. xli, fig. 1, 1875. Moodie, Proc. U. S. Nat. Mus., 37, p. 24, pl. 8, fig. 3, 1909. Schwarz, BeitrÄge zur Paleontologie und Geologie Osterreich-Ungarns und des Orients, Bd. XXI, p. 83, figs. 23, 24, 26, 1908. Type: It is impossible to determine which one of the specimens is the type. There are numerous representatives of the species, as follows: Nos. 140, 1096 G, 8345 G, 8555 G, 1089 G, 2, 132, 133, no number, 1094 G, 8545 G, 8677 G, 1159 G, 105, no number, 1091 G, 7a, 1092 G, 1093 G, 1095 G, 153, and others unnumbered in the American Museum of Natural History; in the U. S. National Museum are the following: Nos. 4458, 4463, 4464, 4514. (Plate 20, fig. 2.) Horizon and locality: Linton, Ohio, Coal Measures. The most abundant species of the Linton Coal Measures. There are over three dozen specimens preserved in the Newberry collection. The species is a clearly marked one, as a rule, though there is great variation in the size of the body and the form of the vertebrÆ. Though there are several apparently complete skulls preserved in the collection, it is impossible to make out the morphology of the elements on account of the amount of crushing to which the skulls have been subjected. Fig. 30. Restoration of Ptyonius. × 1. The head is lancet-shaped, and the muzzle very elongate, slender, and acute at the extremity. The head is in fact a miniature of an ichthyosaur cranium. (Plate 20, fig. 2.) The orbits are large and posterior to the median line. The anterior portion of the skull is narrow, posteriorly truncate, and the mandibular angle is projecting. The posterior portion of the mandible is sculptured. Possibly the entire cranium was also, and this has been lost; in fact, this sculpturing is indicated in one or two specimens. The teeth are conical and sharp, longitudinally striate, and anisodont. There seems to be evidence of palatine or pterygoid teeth, though this needs confirmation. The pectoral plates are well preserved, with the interclavicle a narrow oval, with anterior and posterior prolongations. In one specimen it is sculptured. The clavicles are narrow and slightly sculptured. The abdominal scutellÆ are bristle-like. The vertebrÆ are short, with expanded neural and hÆmal spines. The expanded condition of the neural spines begins over the thoracic region, where they are low. They become well developed in the posterior dorsal region. The caudal fan-shaped spines are larger. The dilated portions form equilateral triangles which stand on moderately short pedicels. They are weakly ridged, and each ridge is prolonged into a narrow acute tooth beyond the margin, 11 of which may be counted on one of the best preserved spines. The longitudinal striÆ are terminated near the pedicel by two others which cross obliquely from each side, and, meeting, present the appearance of the margin of a cup sculptured in relief, from which the striÆ arise. Pedicels smooth. The spines are in contact at their angles, thus forming a continuous line. In a typical specimen there are 6 in half an inch, in another 7, and in a third 8. The ribs are well-developed and slender. No traces of fore limbs have been detected in the numerous specimens, but elements of hind limbs are preserved. In one of these the femur is a small bone, contracted at the middle. The form of the body is snake-like. There were probably from 75 to 100 vertebrÆ in a single animal. The form may be well compared to the modern Amphiuma so far as appearances are concerned; structurally they are widely separate. This species is one which is peculiarly characteristic of the Linton fauna.
Cope, Proc. Am. Phil. Soc., p. 177, 1871. Cope, Geol. Surv. Ohio, II, pt. II, p. 376, pl. xxviii, fig. 1, 1875. Type: Specimen in the American Museum of Natural History. Horizon and locality: Linton, Ohio, Coal Measures. The species is represented by the opposite halves of a single specimen, which includes only the cranium and anterior half of the body. The fan-shaped neural spines commence but a short distance behind the line of the pectoral shields. They are low, with a few coarse ridges, the margin being entire. The abdominal rods are delicate and hair-like. The interclavicle is oval, with a few radiating crests, which originate at the center; in the areas behind there are a few scattered tubercles. The clavicles are ridged near the margin. The cranium is lanceolate in form, and the bones of the dorsum are marked with a few raised points and ridges. The species is about the size of Ptyonius pectinatus Cope, and differs, apparently, from that species in the rather insignificant character of a narrower interclavicle and in the ornamentation of the same. Dedicated to Professor Alexander Winchell, of the University of Michigan.
Cope, Trans. Amer. Phil. Soc., XIV, p. 24, 1869 (Colosteus marshii). Cope, Geol. Surv. Ohio, II, pt. II, p. 375, pl. xxvii, fig. 6; pl. xxviii, fig. 3, 1875. Cope, Proc. Am. Phil. Soc., XII, p. 177, 1871. Type: Specimen No. 1157 G, American Museum of Natural History. Horizon and locality: Linton, Ohio, Coal Measures. The head is elongate lanceolate. The upper surface of the frontal bones is punctate-rugose in relief, with short radii toward the margin. The distal two-thirds
Cope, Geol. Surv. Ohio, II, pt. II, pp. 374, 375, pl. xli, figs. 2 and 3, 1875. Moodie, Bull. Am. Mus. Nat. Hist., XXVI, p. 356, pl. 63, fig. 3, 1909. Type: Specimen No. 8546 G, American Museum of Natural History. No. 8614 G, same museum, is associated with the type specimen. Horizon and locality: Linton, Ohio, Coal Measures. Two well-preserved individuals display peculiarities which indicate specific distinctness from the previously known species of Ptyonius. The abdominal rods are of the coarse type of those of P. marshii. The caudal fans are well developed, and not so wide as in P. pectinatus. The interclavicle is a discoid body of different form from that of P. marshii and I can not detect the clavicles. The sculpture consists of strong ridges, which radiate from the center to near the border. Immediately in front of this interclavicle is the head, which has a different form from that of the other known species. The interorbital width is two-thirds the long diameter of the orbit. The structure of the skull can not be made out. A slender, elongate hind limb is present in the second specimen, and a humerus is well preserved in the type.
Cope, Proc. Am. Phil. Soc., 1871, p. 177. Cope, Geol. Surv. Ohio, II, pt. II, p. 379, pl. xxviii, fig. 5; pl. xxx, fig. 1, 1875. Type: Specimen No. 8615 G, American Museum of Natural History. Horizon and locality: Linton, Ohio, Coal Measures. The specimens of this species indicate that the form was only about half the size of Ptyonius pectinatus. The interclavicle is narrower and more reticulately sculptured. The tail is relatively longer. Abdominal rods hair-like. Ribs distinct. Small limbs are present in one specimen.
Another specimen (456 G, American Museum of Natural History) shows some of the same characters. There is not the slightest basis for the support of this species, so far as I can observe. The ones mentioned by Cope are insufficient. It is in all probability a mutant or variety of Ptyonius pectinatus. Cope, Proc. Phila. Acad. Nat. Sci., 218, 1868. Cope, Trans. Amer. Phil. Soc., XIV, 16. Cope, Proc. Phila. Acad. Nat. Sci., 1868, 217. Cope, Proc. Amer. Phil. Soc., 1871, 41. Cope, Geol. Survey Ohio, II, pt. II, 380, 1875. Type: Œstocephalus remex Cope. Form slender and snake-like; caudal vertebrÆ with elongated, dilated, sculptured neural and hÆmal spines. Cranium lanceolate. Teeth numerous, of nearly equal size. No pectoral shields known; abdomen protected by very numerous bristle-like rods, which converge forwards. A pair of weak posterior limbs; branchihyal bones present. In the only well-preserved species the cranial bones exhibit no sculpture from the parietal region forward. The genus is not very distinct from Ptyonius, but it can not be united with that genus until more complete material is available. The species of the genus share with Ceraterpeton, Urocordylus (334), and Ptyonius, as well as Crossotelos (98), from the Permian of Oklahoma, the elongation, sculpture, and expansion of the neural and hÆmal spines. There are but 2 species, which Cope distinguishes by the following characters: I. VertebrÆ elongate; fan-like caudal processes narrowed. Size large; mandibular teeth of unequal lengths, with the apices turned backward Œstocephalus remex II. Species only known from cranial bones with teeth. Teeth equal, erect, with acute conic apices, 11 in 5 mm Œstocephalus rectidens Œstocephalus remex Cope. Cope, Proc. Phila. Acad. Nat. Sci., p. 217, 1868 (Sauropleura remex). Cope, Proc. Phila. Acad. Nat. Sci., p. 218, 1868 (Œstocephalus amphiumianus). Cope, Trans. Amer. Phil. Soc., XIV, p. 17. Cope, Geol. Surv. Ohio, vol. II, pt. II, p. 381, pl. xxvii, fig. 5; pl. xxxi, fig. 1; pl. xxxii, fig. 1; pl. xxxiii, fig. 2; pl. xxxiv. fig. 4, 1875. Moodie, Proc. U. S. Nat. Mus., 37, p. 27, 1909. Type: Specimen undetermined. The following specimens are to be found: Specimens of Œstocephalus remex Cope in the National Museum, Nos. 4511, 4460, 44/8. There is one specimen of Œstocephalus remex in the University of Chicago. Specimens of the species in the American Museum of Natural History: Nos. 121, 8322 G, 8694 G, no number, 8656 G, 8583 G, 8659 G, 19, 120, 8655 G, 8662 G, 8708 G, 8665 G, 112, 8663 G, 8581 G, 8658 G, 8660 G, 8700 G, 8469 G, 1102 G, 1152 G 142, 8381 G, and obverse, 21, 8664 G, 8672 G, 8592 G, 8684 G. Horizon and locality: Linton, Ohio, Coal Measures. This species is one of the most abundant of the Linton Amphibia. Cope based his description of the species on 9 specimens. There are more than two dozen available at the present time, the majority of them being in the possession of the American Museum of Natural History. There is a single specimen in Walker Museum of the University of Chicago and 3 in the United States National Museum. The numbers of all of these specimens are given above. The material consists, for the most part, of fragmentary portions of the vertebral column, but there are a few skulls more or less complete, though none are sufficiently well preserved for a complete analysis of the characters. The specimens indicate an animal slightly smaller than the modern Amphiuma means of the Mississippi River. Fig. 31. Restoration of Œstocephalus. × 1. It will not be necessary here to enter into a detailed account of each specimen, since this has been done by Cope, and a careful comparison of his descriptions with the originals indicates that his observations are correct. The species, as suggested in the discussion of the genus, is not clearly distinct from those of Ptyonius, and it has largely the characters of that genus. The cranium is long, slender, and wedge-shaped. The teeth are numerous both in the maxillary and in the mandible, one specimen indicating about 30 in a single series. They are all uniformly cylindrical, except at the extremity, where they are flattened and expanded so as to produce a longitudinal edge, which is carried backward on a recurvature of the apex. The bases are anchylosed equally and without enlargement, and no part of the shaft is striate or grooved. The upper surface of the cranium is narrow, with the median suture distinct. The skull surface, with that of the mandible, is smooth. Characteristic of the species are the remarkable length and slenderness of the fan-shaped neural and hÆmal spines, and the absence of an acute serration on their margins. In this species the spines have a laminiform expansion at the base in their plane. One specimen exhibits the pelvic region, including a portion of the tail. The ilium has an expanded anterior extremity and is directed backwards and somewhat inwards on either side of the vertebral column. The femur is nearly straight, short, contracted medially, and expanded distally. The tibia is shorter and is subcylindrical. Beneath the ilium the last chevron of the abdominal rods appears, the outer extremities rising on the base of the tail. The pectoral arch is almost unknown, and Cope based the distinction of Ptyonius, and Œstocephalus on the absence of these plates in the latter genus an uncertain
Œstocephalus rectidens Cope. Cope, Trans. Amer. Phil. Soc., p. 268, Apr., 1874. Cope, Geol. Surv. Ohio, II, pt. II, p. 386, pl. xxvii, fig. 3, 1875. Type: Specimen No. 9033, American Museum of Natural History, collection of J. S. Newberry. Horizon and locality: Linton, Ohio, Coal Measures. The species is indicated by a left dentary bone, with its teeth and external surface preserved. The latter is nearly smooth and without sculpture. The outer face is convex, and the general form is slender, but not curved upward at the extremity. The extremity of the dentary does not show any evidences of teeth. Teeth straight and conic, apex acute, non-plicated. Cope also associated with this species a portion of a caudal series, consisting of 25 vertebrÆ. The centra are elongate and expanded at the extremities. The neural arches have a close union. The neural and hÆmal spines are fan-shaped and striated. The bases are quite narrow.
Cope, Geol. Surv. Ohio, II, pt. II, p. 365, pl. xxxi, fig. 2, 1875. Type: Thyrsidium fasciculare Cope. Established on a species which presents its principal peculiarities in the structure of the vertebrÆ. Two specimens present inferior views of the spinal column, showing that the genus possesses, like Siren, enlarged diapophyses, but they are peculiar in their fan-like form. They resemble slightly the neural spines of the caudals of Ptyonius, but are present on the dorsal vertebrÆ. Whether the caudals of the present species possess ornamented neural spines the specimens do not indicate. The abdomen is protected by the usual hair-like rods arranged en chevron, the angle directed forwards. No indications of limbs can be discovered on the blocks. Without the cranial bones the affinities of this genus can not be determined; while it may be allied to Cocytinus, the vertebrÆ of that form are without peculiar diapophyses. Thyrsidium fasciculare Cope. Cope, Geol. Surv. Ohio, II, pt. II, p. 365, pl. xxxi, fig. 2, 1875. Type: Specimen No. 8552 G, American Museum of Natural History. Horizon and locality: Linton, Ohio, Coal Measures. The best preserved example of this species includes 9 vertebrÆ and the corresponding ventral armature. The centra, seen from below, are much contracted in their form, presenting an obtuse median rib, which expands to the articular extremities. In one or two instances the latter are divided by fracture, and the moderately concave form of the adjacent surfaces is displayed. The diapophyses are of complex form, but the details are concealed by the prevalent thin layer of coal which invests them. An inferior prominence runs parallel to the centrum; outside of this the process is obscurely trilobate and thickened, not flattened, as in the caudal vertebrÆ of Ptyonius. Several ribs (fig. 8) of moderate thickness appear by the side of the diapophyses. Eleven abdominal ribs in 5 mm. The second specimen was originally referred to Œstocephalus remex, as a posterior portion of its vertebral column, immediately preceding the caudal series. This reference appears to be incorrect, although the resemblance between the corresponding parts in the two genera is no doubt considerable, and the alternative of proposing a new genus and species was not at that time advisable. The neural spines are longer than high, and are nearly in contact at their margins; each is marked by about 5 obtuse vertical ribs. A fractured section of the abdominal spines in place displayed at least six layers of them. The material on which the above account is based is imperfect. The specimen figured by Cope (Geol. Surv. Ohio, vol. II, pt. II, pl. xxxi, fig. 2, 1875) is undoubtedly a portion of the vertebral column of Œstocephalus remex. Nos. 4462 and 4480 of the United States National Museum may be representatives of Thyrsidium fasciculare, but they are more probably Œstocephalus remex; if they are the latter this leaves the type as the only known specimen of the species.
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