The Coal Measures Amphibia of North America

by Roy Lee Moodie

Genus ICHTHYERPETON Huxley, 1866.

Huxley, Trans. Roy. Irish Acad., XXIV, p. 195, pl. xxiii, fig. 1; Scientific Memoirs, III, p. 195, pl. 23, fig. 1, 1866.

The genus was founded by Huxley ([334]) for the reception of the species Ichthyerpeton bradleyæ from the Kilkenny Coal Measures of Ireland. The remains of the type specimen represent "the hinder moiety of the trunk, with the greater part of the tail, of an animal whose scaly integument and laterally compressed, fin-like tail might easily lead one to take it for a fish, were not its true position among higher vertebrata settled at once by the digitate hind limb; while its alliance with the labyrinthodonts is indicated by the delicate spicular ossicles, which form a rudimentary dermal shield along the belly." (Huxley.)

Ichthyerpeton squamosum Moodie.

Moodie, Jour. Geol., XVII, No. 1, p. 69, 1909.

Moodie, Proc. U. S. Nat. Mus., 37, p. 24, 1909.

Type: Specimens Nos. 4476 and 4459, U. S. National Museum.

Locality and horizon: Linton, Ohio, Coal Measures.

The present species is based on well-preserved remains from the Linton, Ohio, beds. There are two specimens of the species preserved on blocks of coal and together they represent the greater part of the length of the animal. The species is located in the genus Ichthyerpeton, which was founded by Huxley ([334, p. 351]) on remains from the Coal Measures of Ireland, on account of the character of the dermal covering, which consists of small scales such as Huxley described in the form from Ireland. The specific characters of this form are the small size of the rounded scales, the attenuated tail, the apparent absence of limbs, the character of the ventral scutellation, and the slightly curved condition of the ribs.

It is estimated, from the portions preserved, that the animal attained a length of not less than 3 feet and its body was long and slender. It may have had an appearance similar to the modern caudate genus Siren, though there were doubtless 4 limbs present instead of 2. The slenderness of the body is at variance with the condition found in the type species Ichthyerpeton bradleyæ Huxley, in which the trunk was rather stoutly built. The character of the anterior portion of the body in the present species can not be determined and the skull is wanting. There are no evidences of anterior limbs, although the ventral scutellation preserved would seem to include the pectoral region. No pectoral shields are preserved, nor are there any traces of pelvic girdle or limbs.