Dirk Van Damme

Conservation status of freshwater mussels in Europe: state of the art and future challenges.

Freshwater mussels of the Order Unionida provide important ecosystem functions and services, yet many of their populations are in decline. We comprehensively review the status of the 16 currently recognized species in Europe, collating for the first time their life‐history traits, distribution, conservation status, habitat preferences, and main threats in order to suggest future management actions. In northern, central, and eastern Europe, a relatively homogeneous species composition is found in most basins. In southern Europe, despite the lower species richness, spatially restricted species make these basins a high conservation priority. Information on freshwater mussels in Europe is unevenly distributed with considerable differences in data quality and quantity among countries and species. To make conservation more effective in the future, we suggest greater international cooperation using standardized protocols and methods to monitor and manage European freshwater mussel diversity. Such an approach will not only help conserve this vulnerable group but also, through the protection of these important organisms, will offer wider benefits to freshwater ecosystems.

Internationalization and quality assurance: Towards worldwide accreditation?

This paper addresses two very closely related issues, namely the integration of the quality dimension in internationalization policies in higher education and the adaptation of quality assurance policies and practices to an increasingly international environment. Through an analysis of some issues and challenges in internationalization on the one hand and an overview of recent developments in quality assurance on the other, our objective is to question how internationalization and quality assurance can be integrated. Internationalization policies and practices are lacking a quality assurance dimension and quality assurance approaches are too much confined to national contexts. Can quality assurance give answers to the challenges facing internationalization and can the introduction of an international dimension give a solution to issues in the field of quality assurance. This paper then focuses on the concept of multiple accreditation and the development of worldwide mutual accreditation networks among institutions as a possible avenue for future progress.This paper addresses two very closely related issues, namely the integration of the quality dimension in internationalization policies in higher education and the adaptation of quality assurance policies and practices to an increasingly international environment. Through an analysis of some issues and challenges in internationalization on the one hand and an overview of recent developments in quality assurance on the other, our objective is to question how internationalization and quality assurance can be integrated. Internationalization policies and practices are lacking a quality assurance dimension and quality assurance approaches are too much confined to national contexts. Can quality assurance give answers to the challenges facing internationalization and can the introduction of an international dimension give a solution to issues in the field of quality assurance. This paper then focuses on the concept of multiple accreditation and the development of worldwide mutual accreditation networks among institutions as a possible avenue for future progress.

GRADUAL VERSUS PUNCTUATED EQUILIBRIUM EVOLUTION IN THE TURKANA BASIN MOLLUSCS: EVOLUTIONARY EVENTS OR BIOLOGICAL INVASIONS?

Abstract A running controversy in evolutionary thought was Eldredge and Goulds punctuated equilibrium model, which proposes long periods of morphological stasis interspersed with rapid bursts of dramatic evolutionary change. One of the earliest and most iconic pieces of research in support of punctuated equilibrium is the work of Williamson on the Plio-Pleistocene molluscs of the Turkana Basin. Williamson claimed to have found firm evidence for three episodes of rapid evolutionary change separated by long periods of stasis in a high-resolution sequence. Most of the discussions following this report centered on the topics of (eco)phenotypy versus genotypy and the possible presence of preservational and temporal artifacts. The debate proved inconclusive, leaving Williamsons reports as one of the empirical foundations of the paradigm of punctuated equilibrium. Here we conclusively show Williamsons original interpretations to be highly flawed. The supposed rapid bursts of punctuated evolutionary change represent artifacts resulting from the invasion of extrabasinal faunal elements in the Turkana palaeolakes during wet phases well known from elsewhere in Africa.

The late Cenozoic ampullariidae (mollusca, gastropoda) of the Albertine Rift Valley (Uganda-Zaire)

The Albertine Rift Valley (Uganda-Zaire) contains vast sedimentary sequences of late Cenozoic age. They were deposited in an extensive riftlake, Lake Obweruka, which existed from c. 8 Ma to 2.5 Ma and was comparable in size and depth to the present L. Tanganyika.Many freshwater molluscs that occur in these lacustrine deposits are characterised by their aberrant shell morphology, their extreme ornamentation and general form, making them resemble marine species. This convergence, rare in freshwater molluscs, is called thalassoidism and extreme ornamentation in marine as well as in freshwater molluscs is considered to be the result of a gradual process of prey/predator coevolution.In the present paper the Albertine representants of the ampullariid genera Lanistes and Pila, most of which are new to science, are taxonomically described and their phylogenetic relation, based upon apomorphic characters, is given. In addition the evolutionary history of these freshwater snails in the basin has been reconstructed.In the pre-riftlake environment 3 species of Lanistes occurred, with no special shell adaptations against predation. After the formation of a riftlake, 2 of these, colonising the new lacustrine ecospace, changed morphologically and radiated. The 3 derived lines show minor adaptations against predation. After the extinction of the dominant Lanistes species group around 6 Ma, the sole surviving lacustrine Lanistes suddenly radiates, the ancestral line persisting next to the 3 new daughter lines. This second morphological shift is spectacular as it produces shells with distinct thalassoid features. All the Lanistes species of L. Obweruka became extinct during a cataclysmic event around 4.5 Ma. Populations of the genus Pila colonised lacustrine habitats after this event, the derived form also showing striking thalassoid characters. There is no doubt that the intense morphological change occurred during a brief period, geologically speaking. The degree of morphological change in molluscs appears hence not to be linked with time. After the sudden radiation all lineages remain morphologically stable until they became extinct c. 1 Ma later. This pattern corresponds to the punctuated equilibrium model. Other groups (viviparids, thiarids) show more gradual changes.

Freshwater Molluscs of the Nile Basin, Past and Present

The malacofauna of the Nile is poor compared to that of the Congo and its degree of endemicity is lower. While the highest species richness of the Congo Basin is in stenotopic taxa that live in the rivers and lakes, the highest diversity in the Nile Basin occurs in eurytopic taxa living in fringe habitats such as temporary pools. The paucity of endemics that need perennial waters as well in the Lower Nile as in the White Nile confirms the geological evidence indicating instability and discontinuity in water supply during Plio-Pleistocene times. The fauna of the Nile is predominantly Afrotropical in the Lower Nile and exclusively Afrotropical south of the junction of the White Nile and Blue Nile. Of all sub-basins, the degree of endemicity (either zero or two species) is lowest in the Equatorial Nile, indicating that the perennial aquatic environment in this sub-basin is young (probably Holocene) and lending support to the idea that the Bahr el Arab and White Nile Transcontinental Rift System were hydrologically unstable, with endorheic, alkaline lakes during most of the Plio-Pleistocene (Salama, 1997). In the Lower (Egyptian) Nile and in the Ethiopian Highlands palaearctic faunal components occur, consisting of widespread species and of a limited number of endemics of palaearctic origin, related to Levantine species. Most of these taxa first appear in the fossil record around 2.5 Ma. There is no evidence that the Nile functioned as an invasion route for Eurasiatic species prior to that time. Only Theodoxus niloticus is possibly of Paratethyan origin and may have invaded in the Late Miocene. The main invasion of freshwater molluscs into Africa appears to have occurred via the Horn of Africa in Middle and Late Miocene times. In the East African Rift, a diversified fauna occurs that only shares a fraction of species with the Nile Basin north of the Albert Nile (> ∼5° N). In the equato- rial headwaters, some species from southern Africa reach their northern limit, but the main community consists of species that are either endemic to one of the rift lakes or endemic to the region stretching from Turkana to the Kivu Basins. There hence exists a distinct East African bio-province, that was already recognisable in

Molluscan assemblages from the late Cenozoic of the lower Omo basin, Ethiopia

Abstract The lower Omo basin, southern Ethiopia, preserves formations of sedimentary and pyroclastic rocks which span a substantial range of later Cenozoic time. These formations are often extraordinarily rich in vertebrate fossils and have also afforded a series of molluscan assemblages from contexts radiometrically dated by K/Ar or 14 C. The late Cenozoic molluscan fauna has been previously ill-known in this part of Africa and these assemblages provide a broad faunal zonation for the northern sector of the Eastern Rift valley. The five principal assemblages are here treated as faunal groupings, rather than as formal faunal zones. Three groupings are recognized for the Pliocene/Pleistocene time range, one grouping for the later Pleistocene and one grouping for the subrecent and present.

Palaeobiology and evolution of the Late Cenozoic freshwater molluscs of the Turkana Basin: Iridinidae Swainson, 1840 and Etheriidae Deshayes, 1830 (Bivalvia: Etherioidea)

The palaeobiology of the Late Cenozoic freshwater molluscs that inhabited the Omo-Turkana Basin, situated in the eastern branch of the East African Rift System (Ethiopia, Kenya), remains poorly documented. Here we revise the taxonomy and palaeobiology of the bivalve superfamily Etherioidea from this region and discuss some palaeohydrological implications. In the Iridininae (Mutela, Pleiodon), the genus Iridina Lamarck, 1819 is revived for elongated iridinids with a denticulated hinge, since all fossil Iridininae of the Omo-Turkana Basin and most Miocene-Early Pleistocene Iridininae elsewhere in Africa have denticulate hinges that are not comparable to those of modern Mutela. In addition to the ubiquitous Etheria elliptica (Etheriidae), 11 iridinids are described, five of which are new to science, namely Chambardia feibeli, Iridina turkanica, I. omoensis, I. browni and Pleiodon bentoni. Most species do not show lacustrine adaptations and are/were part of a widespread East African fauna. This confirms the highly unstable character of the Pliocene-Holocene aquatic ecosystems in the Omo-Turkana Basin. Indications for intralacustrine speciation are only observed in the Late Pliocene-Early Pleistocene long-lived (similar to 250 ka or longer) Palaeolake Lorenyang. Williamsons (1981) evolutionary model for the Omo-Turkana Basin molluscs does not apply to the Etherioidea.Synopsis The palaeobiology of the Late Cenozoic freshwater molluscs that inhabited the Omo‐Turkana Basin, situated in the eastern branch of the East African Rift System (Ethiopia, Kenya), remains poorly documented. Here we revise the taxonomy and palaeobiology of the bivalve superfamily Etherioidea from this region and discuss some palaeohydrological implications. In the Iridininae (Mutela, Pleiodon), the genus Iridina Lamarck, 1819 is revived for elongated iridinids with a denticulated hinge, since all fossil Iridininae of the Omo‐Turkana Basin and most Miocene‐Early Pleistocene Iridininae elsewhere in Africa have denticulate hinges that are not comparable to those of modern Mutela. In addition to the ubiquitous Etheria elliptica (Etheriidae), 11 iridinids are described, five of which are new to science, namely Chambardia feibeli, Iridina turkanica, I. omoensis, I. browni and Pleiodon bentoni. Most species do not show lacustrine adaptations and are/were part of a widespread East African fauna. This confirms the highly unstable character of the Pliocene‐Holocene aquatic ecosystems in the Omo‐Turkana Basin. Indications for intralacustrine speciation are only observed in the Late Pliocene‐Early Pleistocene long‐lived (∼25o ka or longer) Palaeolake Lorenyang. Williamsons (1981) evolutionary model for the Omo‐Turkana Basin molluscs does not apply to the Etherioidea.

Late Cenozoic freshwater mollusks of the Wembere-Manonga formation, Manonga Valley, Tanzania

The fossil freshwater mollusks described and analyzed in this chapter were collected by members of the Wembere-Manonga Paleontological Expedition (WMPE) in the Manonga Valley during the 1992 and 1994 field seasons. The following list summarizes basic information about the seven localities from which fossil mollusks were obtained. The abbreviations in parentheses are those used in Table I.

The first vertebrate fossil from Socotra Island (Yemen) is an early Holocene Egyptian fruit bat

Data on the prehistoric biota of the Socotra Archipelago (Yemen) are scarce. We report on the first extinct vertebrate ever recorded from this western Indian Ocean island group. An exceptionally preserved adult specimen of Egyptian fruit bat Rousettus aegyptiacus was found in a calcite flowstone in Hoq Cave on the NE coast of Socotra Island. Accelerator mass spectrometry (AMS) radiocarbon dating on bone fragments estimates the fossil at ca. 7600–7400 cal a BP (radiocarbon age 6669 ± 70 14C a BP) corresponding to an early Holocene wet period in southern Arabia and the Horn of Africa. Morphometric analysis of the skull compared to Recent specimens from the neighbouring mainlands finds the fossil morphologically most similar to Egyptian (Nile Valley and Libyan Desert), not to East African or Middle Eastern populations. The species is currently absent from the Horn of Africa (Somalia and Eastern Ethiopia). Although potentially a stray individual, we also discuss the palaeoenvironmental implications under the hypothetical scenario that the fruit bat is a remnant of an extinct resident population. If so, the extinction of an important pollinator and seed disperser may have impacted the Socotran terrestrial ecosystems.

PALEOECOLOGIC SIGNIFICANCE OF MALACOFAUNA, OLDUVAI GORGE, TANZANIA

Abstract The rich record of vertebrate, hominin and archaeological remains recovered from Olduvai Gorge in northern Tanzania stands in stark contrast to the largely unexplored macroinvertebrate record from the region. Here we examine fossil malacofauna from Olduvai Gorge, inclusive of new discoveries and previous reports, and survey their potential as paleoecologic indicators. Recorded for the first time from Olduvai, an assemblage of fossil bivalve shells is attributed by character comparison to modern Chambardia wahlbergi, a freshwater unionid species widespread across Africa. The fossilized shells were localized in Bed III conglomerate channel deposits, with channel geometry exhibiting scour bases and superimposed fill structures with fining upward sequences. The ecology of recent C. wahlbergi combined with sedimentological data indicate the aquatic environment in this region during Olduvai Bed III times can be reconstructed as a periodically desiccated floodplain bordering a river channel or channels with permanent running water and marked seasonal fluctuations. This paleo-environmental setting presents drastic change compared with that of the lower Bed I and Bed II deposits, when an alkaline/saline lake extended over the site and fresh water was restricted to standing groundwater-fed pools with snail species known today to be intermediate hosts for the trematode genera Schistosoma (schistosomiasis) and Fasciola (fascioliasis). This research enhances details of landscape evolution at Olduvai basin and furthers paleoenvironmental interpretations during the time of Bed III deposition.