CHAPTER XVI. 



THE MICROSAURIAN FAMILY UROCORDYLlDyE, FROM THE COAL MEASURES 



OF OHIO. 



Family UROCORDYLIDiE Lydekker, 1890. 



Lydekker, Cat. Fossil Reptilia and Amphibia, pt. iv, p. 196, 1890. 

 MooDiE, Bull. Am. Mus. Nat. Hist., x.xvi, art. xxv, p. 357, 1909. 



Type of the family: Urocordylus wandesfordii Huxley. 

 Locality and horizon: Coal Measures of Kilkenny, Ireland. 



Stout and long-tailed forms, with the tabulate comua frequently much pro- 

 duced and pitted cranial bones ; lateral lines well-developed ; palate with teeth on 

 palatines, vomers, premaxillae, and maxillae, the two latter elements bearing conical 

 teeth and the others bearing short, stumpy cones, at least in one species; pineal 

 foramen well forward; nostrils and orbits in the anterior part of skull; scapula 

 pecuHarly curved and pointed ; other pectoral elements sculptured ; neural spines 

 and chevrons of caudal vertebras much dilated at their extremities, and pectinated; 

 no caudal ribs ; vertebrae in one genus apparently capped with a sculptured plate 

 as in Zatrachys; tail very long and tapering to a point, 50 to 80 caudal vertebras; 

 dorsal region short; limbs well developed, with clawed digits; carpus and tarsus 

 cartilaginous; endochondrium well formed. 



There are 4 genera which constitute this family: Urocordylus, from the Coal 

 Measures of Ireland; Ceraterpeton, from the Coal Measures of Ireland and Eng- 

 land; Diceratosaurus, from the Coal Measures of Linton, Ohio; Eoserpeton, from 

 the Coal Measures of Linton, Ohio. 



These may be distinguished by the following characters : 



I. Skull triangular, truncated behind, with rounded muzzle and aborted tabulare comua, neural spines of 



caudal vertebrae long, slender, and expanded in a fan-like manner; tail with about 80 vertebrae; 

 ventral scutes oat-like Urocordylus. 



II. Skull parabolic and of great width, with short comua projecting from the supralemporal ; tabulare comua 



nearly twice as long ; neural spines of caudal vertebrse low and wide ; ventral scutes oblong ; caudal 

 vertebrae about 50 Ceraterpeton. 



III. Skull broad with obtuse snout, tabulare comua absent, large, pointed posterior expansions from supra- 



temporal, posterior table within the comua truncate; vertebrae with an apical sculptured plate; 

 caudal vertebras numerous, over 75; ventral scutellae bristle-like, arranged en chevron . . Diceratosaurus. 



IV. Skull a broad oval, with large posterior projecting supratemporal horns, posterior table of skull between 



cornua truncate without the small lateral projection from the supratemporal, orbits a long oval, 

 ribs long, curved and slender, tail unknown, possibly shorter than in other members of the 

 family; it is restored as short in Journal of Geology, xvil, p. 77, fig. 20, 1909, but this is uncertain; 

 the skull has all the characters of the family Eoserpeton. 



The relationships of the family are not far to seek. They fall in immediately 

 with the Amphibamidae and Hylonomidae in being among the most reptile-like of 

 the Paleozoic Amphibia. The group is, however, distinctly amphibian in the pos- 

 session of 4 fingers, with the usual microsaurian phalangeal formula. 



Genus DICERATOSAURUS Jaekel, 1903. 



Jaekel, Neues Jahrbuch f. Mineral., Gcol. u. Paleon., Bd. I, p. 112, 1903. 

 MooDiE, Jour. Geol., xvii, pp. 63-69, figs. 13-15, 1909. 



Type: Diceratosaurus punctolineatus Jaekel. 



Orbits in the anterior two-thirds of the axial skull length, nostrils near to 

 the anterior end of the skull; pineal foramen in the center of the skull roof; skull 



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