  THE TEMNOSPONDYLOUS AMPHIBIA OF THE COAL MEASURES OF NORTH AMERICA. DEFINITION OF THE ORDER TEMNOSPONDYLIA, ZITTEL. 1887. Zittel, Handbuch der Paleontologie, Abth. 1, Bd. 3, p. 384, 1887. Terrestrial or semi-aquatic vertebrata; skull bones pitted and grooved; lateral-line canals present in well-developed form; pineal foramen sometimes absent; sclerotic plates present; vertebrÆ rachitomous or embolomerous; notochord partly persistent; one or two sacral vertebrÆ; tail present, long or short; limbs and girdles well developed; limb bones well ossified and bones of arm and leg separate; pectoral and pelvic girdles composed of the usual stegocephalian elements; an osseous pubis present; a cleithrum present on the scapula; carpus and tarsus ossified, carpals n and tarsals 12 in one form; phalangeal formula, 2, 3, 3, 4, 2 for the hand and 2, 3, 3, 3, 2 for the foot; fore and hind limbs pentadactyl in a few forms; venter covered with an armature of osseous scutes, sometimes overlapping; skin of back bare or armored with heavy plates; ribs heavy, double-headed, curved and moderately long, or short; body short and heavy, as compared to skull about 2 to 1. Range: Coal Measures to upper Permian. Distribution: North America: Illinois, Kansas, Oklahoma, Texas, and Pennsylvania; Europe: Germany, Bohemia; France; Asia: India. Family CRICOTIDÆ Cope, 1884. Cope, Am. Nat., XVIII, p. 38, 1884. General form of the body elongate, with triangular skull and short, stout limbs. Snout narrow, orbits large, elongated oval, situated near the middle of the skull. External bones faintly sculptured, sensory canals conspicuous, parietal foramen large. Teeth conical, of unequal size. Presacral vertebrÆ composed of horseshoe-shaped pleurocentra and hypocentra, the former alone supporting the neural arch. In the caudals the pleurocentra and hypocentra form complete rings, and both elements take part in the support of the neural arch, but the hÆmal arch is borne exclusively by the hypocentra. A close abdominal armor of imbricate scales, arranged in a chevron pattern. Caudal vertebrÆ numerous. Chevrons coÖssified with the intercentra. Moodie, Kans. Univ. Sci. Bull., vi. No. 2, p. 355, 1912. Type: Spondylerpeton spinatum Moodie. The genus is based on a specimen consisting of 9 imperfect vertebrÆ, from the caudal region of a relatively large amphibian. The present genus exceeds Diplospondylus from the Gaskohle of Bohemia (251) by twice its size and is about two-thirds the size of Cricotus heteroclitus Cope (98) from the Permian of Kansas. The vertebrÆ are twice as high as wide, differing thus from Cricotus, in which the vertebrÆ are nearly circular. A character which is of great importance is the large size of the intercentrum, which almost equals the pleurocentrum in size. It is similar to the pleurocentrum in shape, except for the attached neurocentrum and chevron on the latter. The present genus differs from Diplospondylus in the greater length of the intercentrum and pleurocentrum, in the greater size, in the larger proportions Spondylerpeton spinatum Moodie. Moodie, Kans. Univ. Sci. Bull., VI, No. 2, pp. 355-357, pl. 8, figs. 1 and 2; pl. 9, fig. 1, 1912. Type: Specimen No. 793 (26) and obverse, Yale University Museum. Horizon and locality: Mazon Creek, near Morris, Illinois. The species is very imperfectly known. Sufficient is present, however, to show its wide generic differences from other forms of the CricotidÆ. These characters are of a phylogenetic nature and indicate the more primitive nature of the present form, as we would expect from its geological position. The sutures separating the four vertebral elements are clearly apparent. The pleurocentral-neurocentral suture is apparent in 4 vertebrÆ. Fig. 39. The vertebrÆ of Spondylerpeton spinatum Moodie, the only known temnospondyle from the the Mazon Creek shales. × 1. hy, hypocentrum; inc, intercentrum; pc, pleurocentrum; nc, neurocentrum. There is but a single pleurocentrum preserved complete. This shows the form of the attached neurocentrum and chevron, which corresponds to the hypocentrum pleurale according to Fritsch. The pleurocentrum is flattened laterally, with a rather large canal for the notochord. Its sides are marked with 4 longitudinal grooves. Surfaces for the attachment of the ribs are not present, and for this reason, as well as the presence of chevrons, the vertebrÆ are supposed to be caudals. As such they represent an animal of some 3 or 4 feet in length. It was the giant of the Mazon Creek Amphibia. (Plate 4, figs. 1, 2.) Attached to the upper side of pleurocentrum by a sutural union occurs the neurocentrum. The neural arch is quite large and is oval in outline, although somewhat constricted at the tip. The spine of the neurocentrum is rather long and broad at the base, measuring 12 mm. across the anterior zygapophysis. The neurocentrum is laterally flattened and ends in a rather acute and somewhat rugose point. It was probably tipped with cartilage. The anterior zygapophysis occurs well down on the neurocentrum, its lower edge being 5 mm. from the suture separating the pleurocentrum and the neurocentrum. The posterior zygapophysis occurs quite high up on the neurocentrum and lies at a distance of 15 mm. from the pleuro-neurocentral suture, thus indicating an extreme posterior inclination of the neural spine. The posterior zygapophysis of the best preserved vertebra is separated from its mate, the anterior zygapophysis, in the next succeeding vertebra by a space of 5 mm. The ventral surface of the pleurocentrum bears a structure, which is, without doubt, a chevron, although the character of its opening can not be determined. It is elongated and is united by a broad base to the pleurocentrum. Its union is by a clearly defined suture, which is apparent in 3 vertebrÆ. The condition represented by the specimen duplicates almost exactly the condition figured by Cope for the caudal region of Cricotus Cope. The intercentrum of the present form is fully as large as the pleurocentrum. The significance of this has already been mentioned. The body of the centrum is pierced by a large notochordal canal.
Family ERYOPIDÆ Cope, 1882. Cope, Am. Nat., XVI, p. 334, 1882. Large, terrestrial or amphibious vertebrata; skull bones deeply marked with pits and grooves which take the form of lateral-line canals; infra- and supraorbital canals, antorbital commissure, jugal canal, and occipital cross-commissure of the lateral-line system present in Eryops megacephalus Cope; carpus and tarsus osseous; pubis an osseous plate, surrounded in life by a large amount of cartilage; fore and hind limbs pentadactyl; orbits, in the typical genus, located far back on the skull and near the median line; cleithrum present on the scapula; vertebrÆ rachitomous, the intercentrum supporting the arch in the dorsal region; parasphenoid well-developed or reduced; teeth on pterygoids, palatines, prevomers, and parasphenoid. Range: Upper Pennsylvanian to Permian. Distribution: America, Europe, Asia. Type: Eryops megacephalus Cope. Skull long, comparatively narrow; proportion of length to breadth about 9 to 7. Roof bones coarsely sculptured posteriorly, finely sculptured anteriorly. Nasals and premaxillÆ very large; frontals excluded from the orbits by junction of pre- and post-frontals. Pterygoids not meeting in the median line; parasphenoid dagger-shaped, tapering gradually to a point just in front of the palatine foramen; prevomers large. Orbits subcircular, situated in the posterior half of the skull; nares subovate, remote, at a considerable distance from the tip of the skull. Many minute denticles, on pterygoids, palatines, prevomers, and parasphenoid. Teeth circular in cross-section, strongly ribbed near the base, dentine strongly infolded. Three large teeth on each palatine. Mandible without postcotyloid process. VertebrÆ rachitomous. Ribs double-headed. Pubis osseous. Three species (Permian), E. megacephalus, E. latus, and E. willistoni, are assigned to the genus. Eryops is represented in the Carboniferous deposits of North America by incomplete vertebral remains described by Case (94) from near Pittsburgh, Pennsylvania. MOODIE 1. Photograph of type specimen of Erpetosaurus (Tuditanus) radiatus Cope, from the Coal Measures of Linton, Ohio. × 1.3. Original in American Museum of Natural History. 2. Photograph of type specimen of Erpetosaurus tabulatus Cope, from the Coal Measures of Linton, Ohio. × 2. Original in the Zoological Collections of Columbia University. 3. Photograph of the impression of Stegops divaricata Cope, from the Coal Measures of Linton, Ohio. × 2. The specimen figured is in the American Museum of Natural History. Its obverse is in the collections at Walker Museum, University of Chicago. 4. Type and only known specimen of Micrerpeton caudatum Moodie, a branchiosaur from the Coal Measures shales of Mazon Creek, Illinois. × 2. Original in collections at Walker Museum, University of Chicago. Eryops sp. indet. Case, 1908. Case, Annals Carnegie Mus., IV, p. 234, pl. 59, 1908. A dorsal vertebra is very probably from this genus. The specimen consists of a nearly perfect vertebra, lacking only the anterior zygapophysis and the upper portion of the neural spine (plate 18, fig. 2). It shows no character that would warrant its separation from the genus, and indicates a medium-sized individual. The zygapophyses have clean-cut articular faces. The pleurocentra are thickened above, with just well-defined articular faces, which were applied to faces on the neural arch posterior to the origin of the transverse process. The intercentrum is of the familiar halfmoon-shape, thick and heavy below, and thinner toward the extremities; the anterior edge is marked near the top by the indentation found on the intercentra of Eryops. Height of the vertebra from the middle of the lower face of the intercentrum to the middle of the neural canal, 0.035 m.; width of intercentrum 0.026 m. The second recognizable specimen is a neural spine from the caudal series. This is without question a portion of the skeleton of an Eryops. Similar spines were described by Cope as Eryops (Epicordylus) erythrolithicus, but later discoveries seem to show that similar characters occur in other species of the genus as well. The apex of the spine is bifurcate; the space between extremities is concave and perfectly smooth; below the sides of the spine are rather rugose and marked with ridges. The lower portion of the spine is elongated anteroposteriorly and the edges are marked with sharp, double ridges. Three ribs also belong, in all probability, to the genus Eryops. The head of each rib is broad and the articular edge is divided between two faces which meet at an angle somewhat greater than a right angle; the two faces are continuous. The shaft is somewhat flattened and in the undistorted specimens is gently curved. The length of the largest rib is about 0.07 m. Other than these specimens there are several small intercentra (94) and the neural spine of a caudal vertebra from some undetermined amphibian. Family MACRERPETIDÆ Moodie, 1909. Moodie, Bull. Am. Mus. Nat. Hist., XXVI, art. XXV, p. 354, pl. lix, fig. 1, 1909. It has seemed necessary to propose a new family for the reception of the single species Macrerpeton (Tuditanus) huxleyi Cope. The characters exhibited by this species are so different from those offered by other members of the Carboniferous Microsauria that it is clearly distinct. In its cranial characters and the position of the orbits it approaches most nearly to Eryops megacephalus Cope from the Permian of Texas. In some of its characters the present form shows a similarity to Dasyceps bucklandi Lloyd (324), from the Permian of Kenilworth, England; more especially is this similarity found in the form of the skull, the size and shape of the teeth, and the posterior position of the orbits, and their wide removal from the border of the skull. Only a fragment of the skull has hitherto been known, but repeated study of this fragment (123) has disclosed the wide diversity (462) of its characters. An almost complete skull, described below, substantiates the characters based on the fragment. Another species is here added to the genus, based on a The family, MacrerpetidÆ, may be defined (465) as follows: Skull larger than in any other known microsaurian, unless Baphetes proves to be microsaurian; cranial elements sculptured with pits and coarse grooves; lacrimal element present, teeth large, curved inwards and fluted; mandible heavy; orbits located far back on the skull and near the median line so that the interorbital space is about half the space from the outer edge of the orbit to the border of the skull, thus approaching the condition known in Eryops; the ribs (?) are strong, heavy, and curved, with an incipient tubercle. Moodie, Jour. Geol., XVII, No. 1, pp. 72-74, fig. 17, 1909. Type: Macrerpeton huxleyi Cope. The genus Macrerpeton was proposed for the reception of the amphibian species described by Cope as Tuditanus huxleyi (123). This form he placed provisionally in genus Tuditanus, since it seemed to present the same type of sculpturing of the cranial elements similar to that found in T. radiatus Cope. But this species has been removed from Tuditanus and placed in a new genus, Erpetosaurus (462). A close study of the type specimen of Tuditanus huxleyi Cope shows (465) great variation and distinction from any of the species described from Linton, Ohio, or indeed from any Carboniferous form thus far known. The specimen represents the left side of the face, and the characters exhibited by the fragment are supported by more complete material (No. 2933, Am. Mus. Nat. Hist.). The skull shows a close approach to the higher labyrinthodonts in its shape. The orbits are far removed from the border of the skull. The arrangement of the bones of the skull resembles that of Capitosaurus from the Keuper of Europe. The jaw is for the most part slender, with a pronounced downward inflection at the coronoidal part. The teeth are heavy and strong and are curved backwards. They have the strong longitudinal fluting which is characteristic of the labyrinthodonts. Another character which is distinctive is the pattern of cranial sculpture. This consists of inosculating pits and grooves of a coarse character and compares favorably with the sculpturing of Triassic labyrinthodonts. If Macrerpeton really represents a labyrinthodont form of Amphibia it is the oldest of the known LabyrinthodontidÆ, since it seems probable that the Eosaurus vertebrÆ came from a higher horizon. Macrerpeton huxleyi Cope, 1874. Cope, Trans. Am. Phil. Soc., XV, p. 274, 1874. Cope, Geol. Surv. Ohio, II, pt. II, p. 397, pl. xxxiv, fig. 2, 1875. Lesley, Dictionary of Fossils, p. 1237, 1890. Moodie, Jour. Geol., XVII, No. 1, p. 72, fig. 17, 1909. Moodie, Bull. Am. Mus. Nat. Hist., XXVI, art. XXV, p. 354, pl. lix, fig. 1, 1909. Type: Specimen No. 119, American Museum of Natural History. Collection of Dr. J. S. Newberry. (Plate 26, fig. 2.) Horizon and locality: Linton, Ohio, Coal Measures. MOODIE 1. Photograph of type specimen of Erpetosaurus tuberculatus Moodie, from the Ohio Coal Measures. × 1. Original in American Museum of Natural History. 2. Photograph of type of Macrerpeton huxleyi Cope, from the Ohio Coal Measures. × 1. Original in American Museum of Natural History. The first part of the following account of the species, Macrerpeton huxleyi Cope, is a quotation of Cope's description (123) of the type specimen, and the second part deals with the description of the new material. Cope says the species is "Represented by a considerable portion of the face and muzzle of a single individual. A portion of the left mandible, supporting three teeth, remains in place, and almost the entire boundary of the right orbit is preserved. "The fragment indicates a much larger species than any other referred to the genus, and, next to the Leptophractus obsoletus, the largest of the Batrachians of the Ohio Coal Measures. Without more complete remains, it is not easy to determine its generic relations finally. "The form of the head is probably elongate, and the muzzle neither very obtuse nor elongate. The orbit is rather small, and near the middle of the length of the specimen, which is, however, incomplete at both ends. The sculpture of the surface of the head posterior to the orbits, as well as round their borders and for some distance in front of them, consists of a rather coarse pitting. On the middle line, between the orbits and on the muzzle, the intervals become narrower, and are confluent into transverse ridges or a delicate reticulation. The surface of the mandible displays a coarse reticulation. "The teeth are stoutly conic, and with delicately striate grooved cementum. They are slightly recurved. "This species differs from the T. radiatus and T. obtusus in the absence of the area into which the sculpture is thrown. "Longitudinal diameter of orbit, 19 mm.; length of alveolar border supporting three teeth, 13 mm.; diameter of base of tooth, 3 mm.; eight pits in 10 mm. "Dedicated to Professor T. H. Huxley, facile princeps among English systematists, and an important contributor to the knowledge of the extinct Batrachia." The following discussion of the cranial elements, based on the writer's studies (462, 465) of the type, may be appended to Professor Cope's original description. The sutures bounding a few of the elements have been made out in part. The prefrontal element seems well assured. It lies well in front of the orbit, much as in the skull of Capitosaurus from the Keuper of Europe. The lacrimal is, apparently, a very large bone, though its entire extent is not assured. The maxilla is a long, narrow element on the border of the skull. The suture separating this from the lacrimal and jugal is quite clear. The teeth which the maxilla undoubtedly bore are hidden by the remains of the mandible, which lies partly on the edge of the skull. The jugal is a very large element and its boundaries seem well assured. Its size and relations recall the condition in Capitosaurus. It forms a part of the external boundary of the orbit. The lateral suture of the postorbital is evident and is, as shown in the figure, somewhat curved. The remaining elements preserved on the fragmentary skull can not be accurately determined, though their probable position is indicated in plate 30, fig. 2, the lettering being based on the arrangement of these elements in Capitosaurus. The lower jaw is poorly preserved, but what remains shows evidence of being sculptured somewhat after the manner of the cranial elements. It bore strong recurved teeth which are longitudinally striate.
Description of Additional Material of Macrerpeton huxleyi. The additional material of this species which has come to hand consists of an almost complete skull (American Museum No. 2933, two portions); another fragmentary skull (American Museum No. 8572 G and 8532 G); a portion of an interclavicle (American Museum No. 8006); two incomplete vertebrÆ (American Museum No. 8007); and another fragmentary element possibly representing a scapula of this species (American Museum No. 8008). The skull has essentially the shape outlined (462) from a study of the fragmentary type specimen. The muzzle was drawn slightly too broad, but otherwise the restoration is fairly accurate. The specimen is distorted and imperfect, but enough is preserved to give a good idea of the shape and something of the structure of the skull. A portion of the obverse is preserved. The back part of the skull is broken, so that the occiput can not be studied. The length of the skull is one and two-fifths the greatest breadth (across the orbits). The cranial elements are deeply marked with pits and short, shallow grooves. On the left mandible these pits are in a very distinct row, the operculo-mandibular lateral-line. Macrerpeton deani new species. Type: Specimen No. 2934, American Museum of Natural History. Horizon and locality: Linton, Ohio, Coal Measures. (Plate 21, figs. 1, 2.) The material for this species consists of the posterior half of the left mandible and a portion of the right antero-lateral surface of the skull, both incomplete. The reasons for regarding the species as distinct are the large size of the specimens and the manner of the sculpture, as well as the shape of the posterior end of the mandible. Fig. 40. Mandible of Macrerpeton deani new species, from Linton, Ohio. × 0.75. The present species is the largest amphibian of the Linton, Ohio, Coal Measures, exceeding in skull length that of Macrerpeton huxleyi by twice. The largest skull of Macrerpeton huxleyi which has so far come under my notice is 120 mm. in median length. There are 3 skulls of this species known, all of approximately the same size. The skull of Macrerpeton deani must have reached or exceeded a foot in median length. The only species with which it can at all be compared are Eobaphetes kansensis Moodie and Baphetes planiceps Owen, but it is clearly distinct from all other genera of Linton Amphibia. It is possible that when better known Macrerpeton, Eobaphetes, Baphetes, Erpetosaurus, and possibly Dendrerpeton will form a natural group of early labyrinthodont-like Amphibia. The mandible is similar in structure to that of the labyrinthodonts, with the elements marked by radiate flutings. I can detect no evidences of a lateral-line The sculpture is a coarse fluting, with no indications of the sharply marked pits of Macrerpeton huxleyi Cope. The fragment of a skull preserved shows characters of the sculpture which are identical with those of the mandible. The bones are so crushed that it is impossible to tell the limits of the elements. I believe a portion of one orbit is represented on one corner of the block. The cranium appears to have been broad, and the fragment preserved, which is only about one-sixth of the skull, is larger than the entire cranium and mandibles of Macrerpeton huxleyi. The specific distinctness of the form can not be doubted, although it is a matter of regret that it is founded on so small a portion of the osteology of the animal. The species is proposed in honor of Dr. Bashford Dean, to whom I am greatly indebted for many kindnesses during the past 5 years in connection with my studies on Carboniferous Amphibia, particularly in the loan of the entire Newberry collection of Linton, Ohio, Amphibia.
Family ANTHRACOSAURIDÆ Cope, 1875. Cope, Bull. U. S. Nat. Mus., I, p. 10, 1875. Lydekker, R., 1890, Cat. Fossil Reptilia and Amphibia, p. 157. Skull usually triangular and more or less angulated, with the cranial sculpture well marked, the occipital condyles ossified, and the palatine foramina very small and placed far back; dentine of the teeth more or less complexly plicated. A ventral armor of elongated dermal scutes, and probably a sclerotic ring. Bodies of vertebrÆ fully ossified in the adult; intercentra present or absent. According to Atthey's figure (11) of the skull of the type genus, the palatine bears teeth which are situated immediately on the inner side of the maxilla, as in Mastodonsaurus (242). In the typical forms there is no postarticular process to the mandible. The North American species of this family are: Eosaurus acadianus Marsh, Eobaphetes kansensis Moodie, Dendrerpeton acadianum Owen, Dendrerpeton oweni Dawson, Platystegos loricatum Dawson, Baphetes planiceps Owen, Baphetes minor Dawson. There is but little assurance that any of these species belong in this family. They are put there provisionally, pending future discoveries. Huxley suggests the relationship of Eosaurus and Anthracosaurus (Quart. Jour. Geol. Soc., XIX, 1863, p. 65; Scientific Memoirs, II, p. 566). Owen, Quart. Jour. Geol. Soc. London, X, p. 207, pl. ix, 1854. Dawson, Air-breathers of the Coal Period, pp. 10-16, pl. ii, 1863. Type: Baphetes planiceps Owen. Known only from an incomplete skull, which is large, broader than long; squamosals prolonged into obtuse horns. Teeth rather large, heterodont, arranged in a single row. Orbits placed well forward, frontals small, surface bones sculptured. Baphetes planiceps Owen. Owen, Quart. Jour. Geol. Soc. London, X, p. 207, pl. ix, 1854. Dawson, Air-breathers of the Coal Period, pp. 10-16, pl. ii, 1863. Type: Specimen in the British Museum of Natural History. Horizon and locality: Near Pictou, Nova Scotia (Coal Measures). The parts preserved include the premaxillaries, nasals, and portions of the frontal, prefrontal, and maxillary bones. The fossil is embedded in a mass of Pictou Coal from Nova Scotia and consists of the anterior extremity of the cranium (plate 22, fig. 6) and with the exterior surface of the bone embedded in the matrix, and its substance, for the most part, reduced to a thin layer by abrasion of the exposed inner layer. It displays accurately the contour of the fore part of the upper jaw, which was broad, obtuse, and rounded. The premaxillaries, which show some obscure traces of a symphysial suture at the median line, anterior to the nasal or naso-palatine vacuities, extend outwards, on each side, for an extent of 2.5 lines and there join the maxillaries. Traces of round alveoli for teeth, some of which are 2 lines in diameter, are visible on the alveolar border of the premaxillaries. The alveolar border is continued by the maxillary bone for an extent of 4.5 inches beyond the premaxillary border, and this border shows still more distinct traces of alveoli, of a circular form, about a line in diameter and rather close set in a single series. The fore part of the orbit is very unequivocally displayed, the smooth inner or under surface of the bone forming that part being entire; and this shows the fore part of the orbit to be formed, partly by the maxillary, partly by the lacrimal or prefrontal bone in close sutural union therewith, a structure which does not exist in any recent or fossil fish with a dentigerous superior maxillary bone. Where the substance of the bone has been detached so far as to expose the external layer in contact with the coal, as, e.g., on the frontal and part of the prefrontal bones, the external surface of those bones is shown to have been impressed by subhemispherical or elliptical pits, from 1 line to 1.5 lines in diameter, and with intervals of half of that extent. This coarsely pitted character agrees with that presented by the other surface of the similarly broad and flat cranium of the labyrinthodonts. From the characters above specified, therefore, I conclude that this fossil is the fore part of the skull of an extinct family of the labyrinthodonts. It agrees with them in the number, size, and disposition of teeth; in the proportions and mode of connection of the premaxillaries, maxillaries, nasals, prefrontals, and frontals, and in the resultant peculiarly broad and depressed character of the skull. The traces of the nostrils are less definite and satisfactory than the remains of the orbits, bu
Pictou Coal, near Pictou, Nova Scotia, Canada, collected by Dr. J. William Dawson, 1850, and presented by him to the Geological Society of London. Baphetes minor Dawson. Dawson, Canadian Nat. and Jour. Sci., n. s., 1870, V, pp. 98, 99. Type: Specimen in the Peter Redpath Museum, McGill University. Horizon and locality: Coal formation of Nova Scotia. The species was based on a lower jaw of an amphibian, of which a cast had occurred in the coarse sandstone of the coal formation between Ragged Reef and the Joggins Coal Mine. It measured 6 inches in length; its surface was marked on the lower and posterior part with a network of ridges inclosing rounded depressions. The anterior part of the jaw contained about 16 teeth, some of which remained in the matrix. These were stout, conical and blunt, with large pulp cavities, and about 32 longitudinal striÆ, corresponding to the folds of the dentine. Dawson states that this jaw resembles most closely those of Baphetes and Dendrerpeton, but more especially the former. He regarded it as distinct from Baphetes planiceps, and proposed for it the name Baphetes minor. Eosaurus acadianus Marsh. Marsh, Am. Jour. Sci. (2), XXXIV, pp. 1-16, pls. i, ii, 1862. Agassiz, Am. Jour. Sci., XXXIII, p. 138, 1862. Marsh, Quart. Jour. Geol. Soc., XIX, pp. 52-56. Hay, Cat. Fossil Vertebrates (Bull. U. S. Geol. Surv. No. 179, p. 421, 1902). Type: Specimen No. 1648, Yale University Museum. Horizon and locality: South Joggins, Nova Scotia (Coal Measures). The genus and species are founded on two vertebral bodies of the stereospondylous type from the Coal Measures of the South Joggins, Nova Scotia. Marsh's description (404) is as follows: "The general form of the vertebrÆ is cylindrical, but their sides are compressed obliquely, which gives to the contour of the centra a subhexagonal appearance. They are much flattened in the direction of the antero-posterior diameter, which has to the transverse diameter the proportion of 1 to 3. Both the articular terminal facets are deeply and equally Fig. 41. Nova Scotian Amphibia. A. Oblique lateral view of vertebra: of Eosaurus acadianus Marsh, a, pits for articulation of neuropophyses; b, rudimentary transverse process on right lateral surface of centrum. B. Oblique view of vertebrÆ, a, pits for articulation of neuropophyses; b, rudimentary process on lateral surface. C. Posterior view of nearly perfect centrum. D. Transverse section of same vertebra, showing deep concavities of articular terminal facets. E and F. Microscopic sections near surface, showing lacunÆ arranged around an Haversian canal. Magnified 200 diameters. (All figures after Marsh. × 0.75.) "The neuropophyses are not anchylosed to the centrum, as in the mammalia, nor connected to it by sutures, as in the crocodiles; but their union with the vertebra is indicated by two pits, which served for their articulating surfaces. These depressions are situated on the superior surface of the centrum intermediate between the anterior and posterior margins of the extremities. They are circular in form and sink directly into the body of the vertebra; instead of being elongated longitudinally and raised by ridges, as in Ichthyosaurus. The pits are about a line in depth, and in the more perfect of the fossils are not in their original position. The floor of the spinal canal is narrow, being but 5 lines in breadth. A rudimentary transverse process, or exogenous tubercle, is sent off from each lateral surface of the centrum, at points equidistant from the extremities of the vertical diameter. Their position is near the margin of the anterior articular surface, and the edges of these p
Collected by O. C. Marsh at the South Joggins, Nova Scotia. Marsh regarded (404) the vertebrÆ as representing a new type of ichthyosaurian (2), but there can be no doubt that the vertebrÆ belong to some form of the Amphibia, since the description applies equally well to them. In this connection mention must be made of a large rib from the Linton beds preserved in the U. S. National Museum. Only the proximal third of the rib is preserved, but it represents some large form of the Stegocephala. The rib is strongly curved backward, is heavy, and has an incipient tubercle. A cross-section shows that a longitudinal groove occupies the median line on the exposed surface of the rib. This may, however, be due to compression and thus indicate that the rib was hollow. The rib as preserved measures: length, 102 mm.; maximum width, 22 mm.; minimum width, 14 mm. (Nos. 4490, 4489, U. S. National Museum.) Type: Eobaphetes kansensis Moodie. The new name is proposed to replace the generic term Erpetosaurus used for the species E. kansensis described by the writer (Proc. U. S. Nat. Mus., 39, p. 491, 1911), and which later was found to be preoccupied by Newton (Phil. Trans. Roy. Soc. London, 185, p. 573, 1894 B). The genus is very readily distinguished by two prominent characters the short, uniform dentition and the presence of two elongate, oval, internal mandibular foramina on the inner side of the jaw. The genus may be further distinguished by the great depth of the posterior portion of the jaw and the slender anterior part, as well as by the ornamentation, which is typically the rough tuberculated labyrinthodont sculpture on the anterior end of the mandible. This changes gradually to longitudinal grooves and ridges of a rather small size on the posterior portion, a very unusual arrangement for a labyrinthodont. These characters are sustained by those of the skull fragment, in which the dentition is uniform and the sculpture very similar to that of the mandible. The ribs are long, curved, and solid, as in other labyrinthodonts. The internal surface of the mandible shows much similarity to that of the crocodiles and alligators of the present day. The resemblance is not due to homology of structures, but must be regarded as a parallel development of similar characters. Eobaphetes kansensis Moodie. Moodie, Proc. U. S. Nat. Mus., 39, pp. 491-494, figs. 1 to 3, 1911 (Erpetosuchus). Type: Specimen No. 6699, U. S. National Museum. Horizon and locality: Coal Measures of Washington County, Kansas. The species is represented in the collections of the U. S. National Museum by a fragment of the skull, with portions of two ribs (Cat. No. 6699, Vert. Pal. U. S. Nat. Mus.) and the larger part of the left ramus of the mandible (Cat. No. 6680, Vert. Pal. U. S. Nat. Mus.). The mandible was preserved in a large block of coal which contained the impression of the back portion of the mandible from which the bone had been weathered. It was possible to remove the bone and make a plaster cast of the impression. This shows in a very satisfactory manner all of the characters of the external surface. Skull.—Only a portion of the left maxilla, with 14 teeth, and a part of the nasal are preserved. The skull seems to have been laterally crushed and the right side of the skull has been crushed flat under the left. It has not seemed feasible to remove the skull from the matrix. The teeth are uniform, rather short, bluntly conical, curved backward, and coarsely striate. They are somewhat crowded, the bases being separated from each other by only a fraction of a millimeter. The maxilla and portion of the nasal are coarsely sculptured with elongate pits and ridges. A portion of the infraorbital lateral-line canal is preserved. It is simply a rounded groove with three short branches. It lies near the middle of the maxilla. Mandible.—It has been possible to study both sides of the mandible. The left ramus was preserved in the coal, with its inner face exposed. This face is broken by two large oval openings, the internal mandibular foramina. This is the term used by Reynolds for the openings on the inner surface of the alligator jaw. So far as I can ascertain, no other known labyrinthodont mandible displays this character in such a marked degree. Dr. Branson has figured in Anaschisma browni Branson from the Triassic (49) of Wyoming the inner surface of the left ramus, on which there are likewise two openings but differently situated. A similarity between the two mandibles is observed in that the suture separating the prearticular and angular touches the posterior edge of the posterior foramen. Several of the sutures are well preserved and they have been indicated in the drawing (fig. 42). The pillar separating the two foramina is cut by the suture separating the angular and prearticular very much as in Anaschisma, with the difference that in the latter form the angular and prearticular are not approximated. I believe I detect the suture as represented separating the anterior end of the angular from the dentary and splenial. I am assured of the portion near the anterior foramen and also of the part near the tip of the ramus. This shows the angular to be a very elongate element, running very nearly the entire length of the mandible, much as in Anaschisma and other labyrinthodont genera. The splenial is a small, Fig. 42. A. Outer view of mandible of Eobaphetes kansensis Moodie, from the Coal Measures of Washington County, Kansas. Original in U. S. National Museum. × 0.33. Cat. No. 6680. a, angular; r, articular; d, dentary. B. Portion of skull of Eobaphetes kansensis Moodie, from the Coal Measures of Washington County, Kansas. Original in U. S. National Museum. Cat. No. 6699. × 0.33. Lateral-line canal represented by heavy broken line, n, nasal; m, maxilla. C. Inner surface of mandible of Eobaphetes kansensis Moodie, from the Coal Measures of Washington County, Kansas. × 0.33. a, angular; p, prearticular; r, articular; s, splenial. The markings of the inner surface are as indicated in the drawing. The back portion of the angular shows a few radiating lines. The dentary is roughened in two portions: one near the teeth, the other at the tip, where there is a cartilaginous roughening for union with its mate. The remainder of the inner surface is relatively smooth. The outer surface shows at the anterior end the typical labyrinthodont sculpturing, which becomes slight grooves and ridges posteriorly. I detect evidences of the operculo-mandibular lateral-line canal throughout the entire length of the mandible. Its location is indicated by the heavy broken line. The suture between the dentary and angular is quite clear. The suture separating the dentary and splenial joins the angular suture about midway of the length of the jaw.
Ribs.—There are portions of two dorsal ribs preserved on the block of coal with the skull. These show characters very similar to those exhibited by the rib ascribed to Macrerpeton huxleyi Cope, and also those of Metoposaurus diagnosticus von Meyer (242) and Anaschisma. The ribs are solid, heavy, curved, and have a longitudinal groove on the middle of each side. The heads of the ribs in the present specimen are obscured and nothing can be said of them except that they appear to be large.
Owen, Quart. Jour. Geol. Soc. London, IX, p. 66, 1853. Type: Dendrerpeton acadianum Owen. The genus is characterized by Dawson as follows (Phil. Trans., 1882, p. 635): "Lizard-like, with anterior and posterior extremities nearly equal; the skull somewhat elongate with small orbits, and the nostrils placed at the front. The cranial bones sculptured. The teeth plicated at the base, more especially on their inner sides. A series of large teeth on the palate. The body was covered above with imbricated horny scales and had lappets or pendants at the sides. The abdomen was protected by thin bony scales semi-elliptical or oat-shaped in form, and arranged in a chevron pattern. There was probably also a thoracic plate. Two species: D. acadianum and D. oweni. "Type: D. acadianum Owen." Dendrerpeton acadianum Owen. Owen, Quart. Jour. Geol. Soc. London, IX, p. 66, 1853. Dawson, Air-breathers of the Coal Period, p. 17, 1863. Dawson, Acadian Geology, 3d ed., p. 362. Dawson, Phil. Trans. Roy. Soc. London, pt. II, p. 642, pl. 40, figs. 46 to 51; pl. 44, figs. 129 to 137. 1882. Type: Specimens Nos. 434-438, British Museum of Natural History. Horizon and locality: Coal formation at South Joggins, Nova Scotia. (Plate 6.) This species has been fully described and figured by Dawson (Air-breathers of the Coal Period, pp. 17-30, pl. III, figs. 1 to 30, 1863), who gives a detailed account of the discovery of the material of this species by himself and Sir Charles Lyell. He says, in part: "In form, Dendrerpeton acadianum was probably lizard-like; with a broad flat head, short, stout limbs and an elongated tail; and having its skin, and more particularly that of the belly, protected by small bony plates closely overlapping each other. It may have attained the length of 2 feet. The form of the head is not unlike that of Baphetes, but longer in proportion; and much resembles that of the labyrinthodont reptiles of the Trias. The bones "The scapular and sternal bones seem to have been well developed and strong, but only portions of them are known. The fore limb of the adult animal, including the toes, must have been 4 or 5 inches in length, and is of massive proportions. The bones are hollow, and in the case of the phalanges the bony walls were thin, so that they are often found crushed flat. The humerus, however, was a strong bone, with thick walls and a cancellated structure toward its extremities; still, even these have sometimes yielded to the great pressure to which they have been subjected. The cavity of the interior of the limb-bones is usually filled with calc-spar stained with organic matter, but showing no structure; and the inner side of the bony wall is smooth, without any indications of cartilaginous matter lining it. "The vertebrÆ, in the external aspect of their bodies, remind one of those of fishes, expanding toward the extremities, and being deeply hollowed by conical cavities, which appear even to meet in the center. There is, however, a large and flattened neural spine. The vertebrÆ are usually much crushed, and it is almost impossible to disengage them from the stone. * * * in its long neural and hÆmal spines, reminds us of the caudal vertebrÆ of those batrachians and reptiles which have tails flattened for swimming, and probably indicates that this was the case with Dendrerpeton. The ribs are long and curved, with an expanded head, near to which they are solid, but become hollow toward the middle; and the distal extremities are flattened and thin-walled. The posterior seems to have been not larger than the anterior, perhaps smaller. The tibia is much flattened at the extremity, as in some labyrinthodonts, and the foot must have been broad, and probably suited for swimming or walking on soft mud, or both. That the hind limb was adapted for walking is shown not merely by the form of the bones, but also by that of the pelvis, the best preserved specimen of which I have represented (208, pl. III, fig. 28). "The external scales are thin, oblique-rhomboidal or elongated-oval, marked with slight concentric lines, but otherwise smooth, and having a thickened ridge or margin; in which they resemble those of Archegosaurus, and also those of Pholidogaster. * * * The microscopic structure of the scales is quite similar to that of the other bones, and different from that of the scales of ganoid fishes * * * ." Dendrerpeton oweni Dawson. Dawson, Quart. Jour. Geol. Soc. London, XVIII, p. 460. 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 REMAINS OF SKIN AND HORNY SCALES. "In one of my earliest explorations of the reptile-bearing stumps of the Joggins, I observed on some of the surfaces patches of a shining black substance, which on minute examination proved to be the remains of cuticle, with horny scales and other appendages. The fragments were preserved; but I found it impossible to determine with certainty to which of the species whose bones occur with them they belonged, or even to ascertain the precise relations of the several fragments to each other. I therefore merely mentioned them in general terms, and stated my belief that they may have belonged to the species of Hylonomus. "(1) One of my specimens is a flattened portion of cuticle 2.25 inches in length. The greater part of the surface is smooth and shining to the naked eye, and under the microscope shows only a minute granulation. A limited portion of the upper and, I suppose, anterior part is covered with imbricated scales, which must have been membranous or horny and generally have a small spot or pore near the outer margin, some having in addition smaller scales or points on their surfaces. In contact with the upper part of this specimen there were many fragments of the skull of Dendrerpeton oweni. "(2) Another portion of the cuticle, similarly marked, appears to preserve the form of the posterior part of the body and tail of the animal, and also a mark representing the point of attachment of the hind leg; near to which, and along the dorsal ridge, is a portion of the skin covered with much smaller scales. This was found in close proximity to a mass of bones of Dendrerpeton oweni, mingled with some of Hylonomus lyelli. "(3) A third and still larger surface of integument with similar markings has upon it a number of vertebrÆ and detached bones of the small reptile Hylonomus wymani, to be described in the sequel; for which species, however, it would be much too large a covering. "(4) Another well-preserved fragment, less than 2 inches in length, exhibits very different markings. It is nearly covered with very small imbricated scales, thicker than those on the specimens previously described. On either side of what seems to have been the middle line of the back, there is a series of pointed flat horny processes, which probably formed a double spinous crest. Without these there are tufts of strong bristles, and exteriorly to these last are rows of flat, thick, horny plates, transversely wrinkled. Near to these was a row of conical truncated tubercles. Sections of these appendages show them to have been horny and attached to the cuticle. None of them have bony structure. "(5) Near this last portion of cuticle, and possibly belonging to it, are pointed and probably membranous appendages, marked on each side with rows of scales not overlapping and each with a pore in its center. The manner in which these appendages are bent and wrinkled shows that they must have been soft, except at the tips, which seem to have been hard and horny, and they are arranged in series, as if originally placed along the sides of the neck or abdomen, or both. The use of these appendages is not easy to conjecture. They "(6) Some other fragments appear to have belonged to a different species from either of the foregoing. The best preserved specimen, which is about 1 inch in length and half an inch in breadth, is covered with very small imbricated scales. It is crossed by 6 or 7 obscure ridges, which both at the bottom and along a mesial line project into points covered with larger scales. A row of large scales with round pores connects these along the lower side. If, as seems probable, this fragment belonged to the side of the trunk or tail, it would perhaps indicate a division of the subcutaneous muscles into an upper and lower band, as in the newts. A separate fragment with transverse horny ridges and another with a longer lobe, similar in structure to those above mentioned, may perhaps be referred to the same animal. A larger patch of skin presents similar imbricated scales, but without a mesial line, and with an edging of larger scales. "Six species of reptiles have left their bones in the repositories containing these remnants of cuticle. Of these, Dendrerpeton acadianum, was an animal of too great size to have been clothed with integument of this character and of such dimensions. Hylonomus aciedentatus and Hylerpeton dawsoni are each represented by only a single specimen, and these did not occur in proximity to any of the portions of cuticle, except that the appendages were found near a specimen of the former. Of the three remaining species, Dendrerpeton oweni, from its size, the number of specimens found, and the juxtaposition of their bones to the fragments of cuticle, appears to have the best claim to the integument included under Nos. 1, 2, and 3; and in this case, while the creature had its throat, and perhaps its abdomen, armed with bony scales, its upper parts and tail, as well as its limbs, had a uniform covering of small, thin imbricated horny scales, in the manner of many modern reptiles. "If the remaining portions of integument, Nos. 4 and 5, as would seem likely, belonged to two species, both of smaller dimensions, there would seem little reason to doubt that these were Hylonomus lyelli and H. wymani. In this case, both of these species must have possessed a highly ornate covering of horny scales and appendages, comparable with that of many of the modern lizards, while there seems good reason to believe, as stated in a previous paper, that they were in part protected by bony scales somewhat like those of Dendrerpeton. These points, however, we shall consider more in detail under the sections which refer to the species of Hylonomus. "Before leaving these curious specimens of ancient skin, the most ancient I suppose known to exist, it is of interest to observe that the thicker portions, when broken across, have the aspect of jet, or of pure shining coal, and thin slices, under the microscope, have the same rich brown colour with that material, though rather more translucent. When burned, fragments of the substance give a strong flame, and a bituminous and ammoniacal odour. We have thus an example of the production of coal from animal membrane, no doubt gelatinous and horny in the first instance, but which has proved itself capable of the same chemical changes that have been experienced by the vegetable matter buried with it. In order that this substance should be preserved in this way, it would be necessary that it should either be kept dry and hard, or that it should be immediately buried in matter impervious to air and kept moist. The latter conditions are the more probable. The preservative qualities of the peaty vegetable matter imbedded with it must be considered; and it is possible that these hollow stumps, partly filled with fragments of Sigillaria bark, may have formed natural tan-pits, in which animal membranes would be preserved in a manner impossible in ordinary sediments. If this were the case, we may yet find an entire reptile, preserved as a flattened mummy, in one of these strange repositories." Dawson, Proc. and Trans. Roy. Soc. Canada, 1895, XII, p. 77 (sec. IV). Type: Platystegos loricatum Dawson. Dawson's description is as follows: "Head broad and short, orbits very large, cranial bones deeply sculptured; teeth strongly plicated and curved, with sharp edges at apices, especially the inner palatal teeth, which are very large. Many minute teeth on the vomerine bones; vertebrÆ ossified, biconcave; limb bones imperfectly ossified, short; lower surface protected with a thoracic plate and thick, densely imbricated bony scales in transverse rows; body above with thin, round scales, concentrically marked." Platystegos loricatum Dawson. Dawson, Proc. and Trans. Roy. Soc. Canada, XII, p. 77, 1895. Dawson describes the species: "Head about 8 cm. long; when flattened 9 cm. broad across parietal foramen; squamosal and temporal bones projecting backwards in points much behind the condyles; parietal foramen small, orbits large; length of longest tooth seen 7 mm.; cranial bones closely and deeply pitted; humerus with very thin bony walls, cartilaginous within, 3.5 cm. long." Erect tree, coal formation, at the South Joggins; collected by P. W. McNaughton. Type in Peter Redpath Museum at McGill University. Dawson regarded the form as of uncertain relationship. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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