Acrosterigma suduirauti, a new species of the Acrosterigma uniornatum species group (Bivalvia : Cardiidae) from the Philippines

Volume: 8Start Page: 71End Page: 7

The West African enigma: Systematics, evolution, and palaeobiogeography of cardiid bivalve Procardium

Procardium gen. nov. is proposed for a group of early Miocene to Recent large cardiids in the subfamily Cardiinae. The type species is Cardium indicum, the only living representative, previously assigned to the genus Cardium. It is a mainly West African species, with a very limited occurrence in the westernmost Mediterranean. Procardium gen. nov. and Cardium differ markedly with regard to shell characters and have distinct evolutionary and biogeographic histories. Six species, in the early Miocene to Pleistocene range, and one Recent species are assigned to the new genus: Procardium magnei sp. nov., P. jansseni sp. nov., P. danubianum, P. kunstleri, P. avisanense, P. diluvianum, and P. indicum. During the Miocene, Procardium gen. nov. had a wide distribution in Europe, including the Proto-Mediterranean Sea, Western and Central Paratethys and NE Atlantic, with a maximum diversity during the Langhian and Serravallian. Its palaeobiogeographic history was strongly controlled by climate. During the Langhian stage, warm conditions allowed the genus to reach its highest latitude, ca. 54° N, in the southern North Sea Basin. With cooling, its latitudinal range gradually retreated southward, becoming mainly Mediterranean in the Pliocene–Pleistocene, and West African at present

[poster] Grafische vormgeving in Nederland, een eeuw : 14 maart - 18 april 1993 Breda De Beyerd /

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Mollusc biodiversity in late Holocene nearshore environments of the Caspian Sea: A baseline for the current biodiversity crisis

The Caspian Sea is an evolutionary island whose rich and endemic fauna have evolved in partial isolation over the past two million years. Baseline studies of pre-20th Century communities are needed in order to assess the severity of the current Caspian biodiversity crisis, which mostly involves invasive species. An inventory of late Holocene shelly assemblages (c. 2000–2500 cal yr BP) from outcrops in and around Great Turali Lake (Dagestan, Russia) shows a diverse nearshore community consisting of 24 endemic Caspian species, two invasive species and two Caspian native species that lived in a shallow embayment with mesohaline salinities of circa 5–13 psu (parts per thousands). This pre-crisis Holocene Caspian mollusc community serves as a baseline against which modern mollusc diversity measurements can be evaluated. Examination of faunas from similar environments living today and in the past illustrates the dramatic changes in nearshore communities during the 20th Century. Our study identifies a habitat that may have served as a refuge, but that is currently under threat from invasive species. The severity of the Caspian biodiversity crisis is comparable with other well-known biodiversity crises in semi-isolated ecosystems such as the cichlid fish communities of Lake Victoria, Africa.Applied Geolog

Mollusc species from the Pontocaspian region – an expert opinion list

Defining and recording the loss of species diversity is a daunting task, especially if identities of species under threat are not fully resolved. An example is the Pontocaspian biota. The mostly endemic invertebrate faunas that evolved in the Black Sea – Caspian Sea – Aral Sea region and live under variable salinity conditions are undergoing strong change, yet within several groups species boundaries are not well established. Collection efforts in the past decade have failed to produce living material of various species groups whose taxonomic status is unclear. This lack of data precludes an integrated taxonomic assessment to clarify species identities and estimate species richness of Pontocaspian biota combining morphological, ecological, genetic, and distribution data. In this paper, we present an expert-working list of Pontocaspian and invasive mollusc species associated to Pontocaspian habitats. This list is based on published and unpublished data on morphology, ecology, anatomy, and molecular biology. It allows us to (1) document Pontocaspian mollusc species, (2) make species richness estimates, and (3) identify and discuss taxonomic uncertainties. The endemic Pontocaspian mollusc species richness is estimated between 55 and 99 species, but there are several groups that may harbour cryptic species. Even though the conservation status of most of the species is not assessed or data deficient, our observations point to deterioration for many of the Pontocaspian species