Robin C Whatley

Praecypridea: a new non-marine ostracod genus from the Jurassic and Early Cretaceous of Europe, North and South America, and Africa

The genus Praecypridea gen. nov. (Cypridoidea, Family Cyprideidae Martin, 1940) is described and thus far comprises four species: the type species Praecypridea acuticyatha (Schudack, 1998) comb. nov., Praecypridea postelongata (Oertli, 1957) comb. nov., Praecypridea suprajurassica (Mojon, Haddoumi & Charriére, 2009) comb. nov. and Praecypridea acuta (Moos, 1959 in Wicher, 1959) comb. nov. Representatives of the new genus have been described from the Middle to Late Jurassic of Europe, North America and Africa and the Early Cretaceous of South America, with other presumed representatives also occurring in the Early Cretaceous. Species of Praecypridea are considered to represent members of the ancestral lineage of the extinct genus Cypridea Bosquet, representatives of which flourished in non-marine habitats of latest Jurassic to Early Cretaceous age and account for the first period of abundance of the non-marine Cypridoidea.

Variable noding and palaeoecology of a Middle Jurassic limnocytherid ostracod: implications for modern brackish water taxa

Abstract No less than seven junior synonyms exist of Theriosynoecum kirtlingtonense Bate, 1965 . This taxonomic confusion has been brought about by variations in the degree and patterns of noding within a single species, which was widespread both geographically — from the south of England to the Hebrides — and in the palaeoenvironments it occupied — from freshwater to polyhaline. A critical analysis is undertaken of the taxonomy of Theriosynoecum kirtlingtonense within a framework of palaeoenvironmental constraint, using only those bio-characters which are invariable at the intraspecific level. The distribution of the species in a section of the upper Bathonian Forest Marble Formation at Tarlton in Gloucestershire, is investigated. The population age structure was used to determine those levels in which the species occurs as an autochthonous component, and its variable noding investigated with respect to salinity variations. All aspects of noding in this limnocytherid and in the Neogene to Recent brackish water species Cyprideis torosa (Jones, 1850) are compared and contrasted and both are shown to be related fundamentally to salinity.