Abstract
THE Placoderms are of considerable interest to the palæońtologist, since they are the earliest of the gnathostomatons vertebrates. In 1934, Erik A:son Stensiö published the first part of a monograph of this sub class,. with supplements in 1936 and 1939. The present work (on the Placodermi of the Upper Devollian of East Greenland, published as Bd. 139 of the Meddelelser om Grønland udgivne of Kommissionen for Videnskablige Undersøgelser i Grønland. Pt. 1, pp. 662 with 308 text figs. ; Pt. 2, 77 plates (København: C. A. Reitzels Forlag, 1948.) 55 Kr.) constitutes the second part of the monograph and treats of the sub-family Bothriolepinæ, in which two genera, Bothriolepis and Grossilepis gen. nov., are recognized. The order Antiarchi, to which the subfamily belongs, appeared in the Middle Devonian and became extinct in the Upper Devonian. While off the main line of vertebrate evolution, the order was probably derived from early, primitive Euarthrodires and deserves notice because of its high specialization. The author considers that the order falls into two groups, which he names the Asterolepiformes and the Bothriolepiformes, and the Bothriolepidae form one of the four families of the second group. The work is divided into two parts, the first being a detailed description of the anatomy of the subfamily with a discussion of the homology of the bones, and the second is a full account of all previously described forms and a revision of their systematic position. Undoubted remains of pelvic fins have been found. The work is characterized by its comprehensiveness and by the meticulous care that one has learned to associate with the author's previous publications. It is valuable not only on account of the considerable additions to our knowledge of the subfamily, but also because it gives command of all previous work in the same field.
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Primitive Vertebrate. Nature 164, 648 (1949). https://doi.org/10.1038/164648b0
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DOI: https://doi.org/10.1038/164648b0