XII - On the internal structure of some mesozoic brachiopoda

Abstract

The present paper shows how a method of research hitherto but tentatively used by a few workers on the internal characters of Brachiopod shells has been elaborated and applied to certain Mesozoic genera of different families, and has resulted in establishing the relationships of the forms examined more satisfactorily than by methods hitherto employed. It embodies some results of two years’ research on the identification and classification of such numerous species of the Brachiopod families Rhynchonellidae, Terebratulidae, and Terebratellidae, as are found in Jurassic and Cretaceous rocks. At the present time less than half of the Mesozoic Brachiopods are specifically determinable, and little or nothing is known of their internal structure, their mutual relationship, or their evolution. This is probably because internal casts are rare, and in Jurassic and Cretaceous species the two valves are not as a rule found detached from one another.

A taxonomic and phylogenetic study of Kutchithyris – A Jurassic terebratulide from Kutch, India

“…T. dhosaensis is a highly elongated form and resemble K. ingluviosa, which was also placed by Buckman (1918) in Lobothyris. Muirwood (1934), while studying Terebratula punctata, the type species of Lobothyris remarked that many of the species included by Buckman as Lobothyris can be distinguished from L. punctata by marked diVerences in external characters. Lobothyris is a form having subcircular to subelliptical outline, plano-convex to moderately biconvex lateral proWle and rectimarginate to incipiently sulciplicate anterior commissure (Muirwood, 1934(Muirwood, , 1965Cooper, 1983) T. dhosaensis is a highly elongated, and inXated, biconvex, biplicate form with a thick, moderately incurved beak unlike Lobothyris.…”

“…Two outgroups have been chosen, an Early to Middle Bathonian terebratulide genus, Lobothyris, known from Europe, Turkey and Somaliland, and a Bathonian -Callovian genus Holcothyris known from Burma, England and France. Lobothyris is ventriconvex, with loop length nearly half the dorsal valve length (Muirwood, 1934;Cooper, 1983). Holcothyris is unequally biconvex, anterior commissure paraplicate and shell surface radially capillate (Sahni, 1940;Cooper, 1983).…”

“…Buckman (1918) placed T. breviplicata (Kitchin, 1900) in the genus Lobothyris Buckman. Many European species that were included by Buckman (1918) in Lobothyris were externally quite diVerent (Muirwood, 1934) and they were reassigned to diVerent genera by later workers (e.g. Mitra, 1960Mitra, , 1974Mitra, , 1978Cooper, 1983).…”

3D morphometry of polyconitid rudist bivalves based on grinding tomography

“…The earliest techniques of fossil data capture and reconstruction were based on physical reconstructions: traces made of wax and plastic sheets of appropriate thickness (Born 1883; Sollas and Sollas 1913;St. Joseph 1937) or simple graphic reconstructions (Muir-Wood 1934;Ovcharenko 1967) were used for three-dimensional reconstructions. However, the most frequently used methods have been film photography (directly from the fossil surface or through a microscope) and acetate peels.…”

Tomographic techniques for the study of exceptionally preserved fossils

“…The approach is, however, adaptable to a variety of scales and taxonomic groups, and various grinding tomographs (e.g. Simpson 1933;Croft 1950;Ager 1965;Sutton et al 2001) have been used on a wide range of fossils; studies of the internal structures of fossil brachiopods, in particular, have become heavily reliant on Sollas-style tomography since the pioneering work of Muir-Wood (1934).…”