Studies of Early Jurassic brachiopoda and their distribution, with special reference to Argentina

• Main Author: Mancenido, M. O.
• Published: Swansea University 1979
• Subjects: 560
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637993

The first part of the present thesis consists of a brief survey of previous research on the subject and sets out the objectives, terminology and methodology followed in the study. The second part is entirely devoted to a monographic description of the Early Jurassic articulate brachiopod faunas of three key areas, providing in most cases photographic illustrations for the first time. A major chapter dealing vdth Argentina is based upon the author's personal sampling from the Provinces of San Juan, Mendoza and Neuqudn in the Argentine Andes, and supplemented by museum collections from these and additional areas. About thirty taxa are described, among them six new species, three new subspecies and one new terebratulid genus (Peristerothyrie). It is the first time that South American Mesozoic brachiopods have been investigated with the help of serial grinding techniques to reveal their internal structures. In another chapter the brachiopod assemblages from the islands of Timor and Seram (Indonesian Archipelago) are revised on the basis of museum collections and published data. A reappraisal of twenty-seven taxes reported previously has revealed the existence of several subjective q'nonyms, one homonym -thioh had to be renamed- and several genera are recorded for the first time from that area. The next chapter provides further new records of many genera which have been recognized in a reassessment of museum collections from western Greece and an examination of undescribed material from east-central Greece. The whole assemblage comprises more then thirty taxes, including a new species. In the third part of the thesis the new evidence provided by the systematic studies is combined with a review of the relevant literature and the patterns of distribution of most known genera are analysed on a world-wide scale. A series of forty-seven maps displaying the occurrences as compiled, supports the distinction of the following kinds of distribution: Pandemic, Borealoid, Boreal, Sub-boreal, Tetbyoid, Meaogeal, Sub-mesogeal and Pacificoid.