Trackway of a Pennsylvanian Tetrapod (Amphibian)

WIGGINS, R.C.*; McCLELLAND, S.: Trackway of a Pennsylvanian Tetrapod (Amphibian?)

The trackway of a tetrapod, worm tracks, fern imprints, and other surface features fossalized in a soft mud from the Pennsylvanian period have been recovered from a West Virginia coal strip-mine. Stride and pace analysis over a recovered distance of about 150 cm indicate that the tetrapod featured four gracile digits on the presumptive forelimb and five on the hind limb, with stocky body proportions. The stride length between each imprint of the same limb is essentially constant at 29 cm, apparently in a slow walk. There is no overstride of one limb’s imprints upon the other, indicating the the trunk length is neither relatively long with short limbs, nor short with long limbs. The palmar (3.5 cm diameter) and plantar (4.0 cm diameter) imprints are separated from left to right by a pace width of about 14 cm (center to center). The pace angulation from righ to left, etc measured 95-97 degrees, which falls in the range of living salamanders and reptiles, and indicates the limbs were relatively well positioned under the weight of the body. The absence of a tail imprint indicates it was either missing, too short to drag in the mud, or held errect. The palmar and plantar imprints are smooth, i.e. without scales, under magnification which shows fine detail in other surface features of the trackway. The trackway has been interpreted as evidence of an amphibian in the Pennsylvanian period.

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