The impact of late Holocene environmental change on lacustrine Ostracoda in Armenia

Lake Sevan, Armenia, is an ancient lake, although it evolved into its present form only in the Holocene. The ostracod population was dominated by extant, spatially widespread species that have been recorded throughout Europe and Asia (e.g. Limnocythere inopinata, Ilyocypris bradyi, Cyprideis torosa, Candona candida and Candona neglecta), although a small proportion of the association is restricted to the Caucasus (e.g. Fabaeformiscandona caucasica). Diversity appears to reflect the gradual increase in water depths and environmental heterogeneity during the Sub-boreal European climatic phase (late in the Khvalynian climatic phase of the Caspian region). The muds, silts and sands penetrated by the boreholes contain shallow water ostracods indicating water depths of about 5 to 20 m. None of the boreholes penetrated deeper water deposits, so that Fabaeformiscandona dorsobiconcava, which lives at depths below c.40 m in the modern lake, was not found. Salinity was no greater than oligohaline; and water temperatures appear to have been cool. As is the case today, there were a number of streams transporting ostracods (such as Prionocypris zenkeri and Ilyocypris bradyi) into the lake and weeds were abundant. The Holocene association of Lake Sevan is unusual in that it is one of the few in which bisexual populations of Limnocythere inopinata occur

Taxonomy Of Quaternary Deep-Sea Ostracods From The Western North Atlantic Ocean

Late Quaternary sediments from Ocean Drilling Program (ODP) Hole 1055B, Carolina Slope, western North Atlantic (32°47.041’ N, 76°17.179’ W; 1798 m water depth) were examined for deep-sea ostracod taxonomy. A total of 13 933 specimens were picked from 207 samples and c. 120 species were identified. Among them, 87 species were included and illustrated in this paper. Twenty-eight new species are described. The new species are: Ambocythere sturgio, Argilloecia abba, Argilloecia caju, Argilloecia keigwini, Argilloecia robinwhatleyi, Aversovalva carolinensis, Bythoceratina willemvandenboldi, Bythocythere eugeneschornikovi, Chejudocythere tenuis, Cytheropteron aielloi, Cytheropteron demenocali, Cytheropteron didieae, Cytheropteron richarddinglei, Cytheropteron fugu, Cytheropteron guerneti, Cytheropteron richardbensoni, Eucytherura hazeli, Eucytherura mayressi, Eucytherura namericana, Eucytherura spinicorona, Posacythere hunti, Paracytherois bondi, Pedicythere atroposopetasi, Pedicythere kennettopetasi, Pedicythere klothopetasi, Pedicythere lachesisopetasi, Ruggieriella mcmanusi and Xestoleberis oppoae. Taxonomic revisions of several common species were made to reduce taxonomic uncertainty in the literature. This study provides a robust taxonomic baseline for application to palaeoceanographical reconstruction and biodiversity analyses in the deep and intermediate-depth environments of the North Atlantic Ocean