The carpus of Eryops and the structure of the primitive chiropterygium. Bulletin of the AMNH ; v. 48, article 10.
Supplemental Materials
Date
1923
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Journal Title
Journal ISSN
Volume Title
Publisher
New York : Published by order of the Trustees, American Museum of Natural History
DOI
DOI
Abstract
"(One) Eryops had only four digits in the manus. (2) Eryops possessed a well-developed prepollex. (3) The carpus (as well as the tarsus) consists of two moieties; the radius (tibia) moiety, embracing the prepollex (prehallux) and carpal elements, forming the first preaxial ray, and the ulna (fibula) moiety, including the digits and their carpals, converging toward the ulna (fibula). The distinctness of these two moieties is further demonstrated by the subdivisions of the carpal (or tarsal) musculature. (4) The pectoral appendage of Eryops is readily comparable with the pectoral fin of the rhipidistian crossopterygians. The distinctness of the two primary series of carpal elements even in these forms is obvious. (5) All known Amphibia, recent and fossil, possess only four digits in the manus, but embryological and indirect palaeontological evidence allows us to infer that the most primitive Amphibia had a prepollex, five digits, and a postminimus in the hand; a prehallux, five digits, and a postminimus in the foot. (6) The primitive chiropterygium was therefore at least seven-rayed in both the manus and pes, but with a tendency toward a reduction in the two marginal rays, which has proceeded furthest in the last postaxial ray. (7) The carpus of Eryops and the primitive chiropterygium possessed three medialia and one centrale, as well as the radiale, intermedium, ulnare and carpalia. (8) The phalangeal formula of Eryops was only 2-2-3-2 in the manus"--P. 287-288.
Description
p. 279-288 : ill. ; 24 cm.
Includes bibliographical references (p. 288).
Includes bibliographical references (p. 288).
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