Identification of fossil worm tubes from Phanerozoic hydrothermal vents and cold seeps

One of the main limitations to understanding the evolutionary history of hydrothermal vent and cold seep communities is the identification of tube fossils from ancient deposits. Tube-dwelling annelids are some of the most conspicuous inhabitants of modern vent and seep ecosystems, and ancient vent and seep tubular fossils are usually considered to have been made by annelids. However, the taxonomic affinities of many tube fossils from vents and seeps are contentious, or have remained largely undetermined due to difficulties in identification. In this study, we make a detailed chemical (Fourier-transform infrared spectroscopy and pyrolysis gas-chromatography mass-spectrometry) and morphological assessment of modern annelid tubes from six families, and fossil tubes (seven tube types from the Cenozoic, 12 Mesozoic and four Palaeozoic) from hydrothermal vent and cold seep environments. Characters identified from these investigations were used to explore for the first time the systematics of ancient vent and seep tubes within a cladistic framework. Results reveal details of the compositions and ultrastructures of modern tubes, and also suggest that two types of tubes from ancient vent localities were made by the annelid family Siboglinidae, which often dominates modern vents and seeps. Our results also highlight that several vent and seep tube fossils formerly thought to have been made by annelids cannot be assigned an annelid affiliation with any certainty. The findings overall improve the level of quality control with regard to interpretations of fossil tubes, and, most importantly, suggest that siboglinids likely occupied Mesozoic vents and seeps, greatly increasing the minimum age of the clade relative to earlier molecular estimates

Biology and conservation of freshwater bivalves : past, present and future perspectives

Freshwater bivalves have been highly threatened by human activities, and recently their global decline has been causing conservational and social concern. In this paper, we review the most important research events in freshwater bivalve biology calling attention to the main scientific achievements. A great bias exists in the research effort, with much more information available for bivalve species belonging to the Unionida in comparison to other groups. The same is true for the origin of these studies, since the publishing pattern does not always correspond to the hotspots of biodiversity but is concentrated in the northern hemisphere mainly in North America, Europe and Russia, with regions such as Africa and Southeast Asia being quite understudied. We also summarize information about past, present and future perspectives concerning the most important research topics that include taxonomy, systematics, anatomy, physiology, ecology and conservation of freshwater bivalves. Finally, we introduce the articles published in this Hydrobiologia special issue related with the International Meeting on Biology and Conservation of Freshwater Bivalves held in 2012 in Braganc¸a, Portugal.We would like to express our gratitude to our sponsors and institutions, especially to the Polytechnic Institute of Braganca for all the logistic support. We acknowledge all keynote speakers, authors, session chairpersons and especially to all attendees whose contributions were fundamental for the success of this meeting. We would also like to thank all referees of this special issue and to Koen Martens, Editor-in-Chief of Hydrobiologia, for all the valuable comments and suggestions. The chronogram was built with the help of the expert opinion of fellow colleagues Rafael Araujo, Arthur Bogan, Kevin Cummings, Dan Graf, Wendell Haag, Karl-Otto Nagel and David Strayer to whom we are very grateful. The authors acknowledge the support provided by Portuguese Foundation for Science and Technology (FCT) and COMPETE funds-projects CONBI (Contract: PTDC/AAC-AMB/117688/2010) and ECO-IAS (Contract: PTDC/AAC-AMB/116685/2010), and by the European Regional Development Fund (ERDF) through the COMPETE, under the project "PEst-C/MAR/LA0015/2011"

Shark fossil diversity (Squalomorphii, Squatinomorphii, and Galeomorphii) from the Langhian of Brielas (Lower Tagus Basin, Portugal)

The fossiliferous marine Miocene sediments of the Lower Tagus Basin (Portugal) present a great diversity of Chondrichthyes forms. The current study focuses on the fossil sharks from the Langhian Vc unit of the Brielas section, located in the Setúbal Peninsula. A total of 384 isolated fossil teeth were analysed and ascribed to 17 species from the Orders Hexanchiformes, Squaliformes, Squatiniformes, Lamniformes, and Carcharhiniformes. Centrophorus granulosus and Iago angustidens are described for the first time in Portuguese sediments, whereas Pachyscyllium dachiardii and Rhizoprionodon ficheuri represent only their second reported occurrence. Galeorhinus goncalvesi was already known from the Portuguese uppermost Miocene (Alvalade Basin), but it is now recognized in older sediments. Furthermore, the new material seems to include the first reported occurrence of Hexanchus cf. agassizi in Miocene sediments. As a whole, these new findings support the previous palaeoenvironment characterization of a warm infralittoral setting gradually deepening to a circalittoral one, where seasonal upwelling phenomena could have occurred

Miocene waterfowl and other birds from central Otago, New Zealand

Copyright © The Natural History Museum 2007Abundant fossil bird bones from the lower Bannockburn Formation, Manuherikia Group, an Early-Middle Miocene lacustrine deposit, 16–19 Ma, from Otago in New Zealand, reveal the “St Bathans Fauna” (new name), a first Tertiary avifauna of land and freshwater birds from New Zealand. At least 23 species of birds are represented by bones, and probable moa, Aves: Dinornithiformes, by eggshell. Anatids dominate the fauna with four genera and five species described as new: a sixth and largest anatid species is represented by just one bone. This is the most diverse Early-Middle Miocene duck fauna known worldwide. Among ducks, two species of dendrochenines are most numerous in the fauna, but a tadornine is common as well. A diving petrel (Pelecanoididae: Pelecanoides) is described, so extending the geological range of this genus worldwide from the Pliocene to the Middle Miocene, at least. The remaining 16 taxa are left undescribed but include: a large species of gull (Laridae); two small waders (Charadriiformes, genus indet.), the size of Charadrius bicinctus and Calidris ruficollis, respectively; a gruiform represented by one specimen similar to Aptornis; abundant rail (Rallidae) bones, including a common flightless rail and a rarer slightly larger taxon, about the size of Gallirallus philippensis; an ?eagle (Accipitridae); a pigeon (Columbidae); three parrots (Psittacidae); an owlet nightjar (Aegothelidae: Aegotheles sp.); a swiftlet (Apodidae: Collocalia sp.); and three passerine taxa, of which the largest is a member of the Cracticidae. The absence of some waterbirds, such as anserines (including swans), grebes (Podicipedidae) and shags (Phalacrocoracidae), among the abundant bones, indicates their probable absence from New Zealand in the Early-Middle Miocene.T. H. Worthy, A. J. D. Tennyson, C. Jones, J. A. McNamara and B. J. Dougla

Global Biodiversity and Phylogenetic Evaluation of Remipedia (Crustacea)

Remipedia is one of the most recently discovered classes of crustaceans, first described in 1981 from anchialine caves in the Bahamas Archipelago. The class is divided into the order Enantiopoda, represented by two fossil species, and Nectiopoda, which contains all known extant remipedes. Since their discovery, the number of nectiopodan species has increased to 24, half of which were described during the last decade. Nectiopoda exhibit a disjunct global distribution pattern, with the highest abundance and diversity in the Caribbean region, and isolated species in the Canary Islands and in Western Australia. Our review of Remipedia provides an overview of their ecological characteristics, including a detailed list of all anchialine marine caves, from which species have been recorded. We discuss alternative hypotheses of the phylogenetic position of Remipedia within Arthropoda, and present first results of an ongoing molecular-phylogenetic analysis that do not support the monophyly of several nectiopodan taxa. We believe that a taxonomic revision of Remipedia is absolutely essential, and that a comprehensive revision should include a reappraisal of the fossil record

Upper Toarcian (Lower Jurassic) marine gastropods from the Cleveland Basin, England: systematics, palaeobiogeography and contribution to biotic recovery from the early Toarcian extinction event

Here we describe a new upper Toarcian (Lower Jurassic) marine gastropod fauna from rocks of the Cleveland Basin exposed on the North Yorkshire coast of England. The fossil assemblage consists of 16 species, of which three are new: Katosira ? bicarinata sp. nov., Turritelloidea stepheni sp. nov. and Striactaenonina elegans sp. nov. Four species are described in open nomenclature as Tricarilda ? sp., Jurilda sp., Cylindrobullina sp. and Cossmannina sp. The other species have previously been described: Coelodiscus minutus (Schübler in Zieten), Procerithium quadrilineatum (Römer), Pseudokatosira undulata (Benz in von Zieten), Palaeorissoina aff. acuminata (Gründel), Pietteia unicarinata (Hudleston), Globularia cf. canina (Hudleston), Striactaeonina cf. richterorum Schulbert & Nützel, Striactaenonina aff. tenuistriata (Hudleston) and Sulcoactaeon sedgvici (Phillips). Most of these species are the earliest records of their respective genera and show palaeobiogeographical connections with contemporary gastropod associations from other regions of Europe and South America. The taxonomic composition of the upper Toarcian Cleveland Basin gastropod assemblage differs substantially from the faunas of the upper Pliensbachian and lower Toarcian Tenuicostatum Zone, showing the strong effect of the early Toarcian mass extinction event on the marine gastropod communities in the basin. Only a few gastropod species are shared between the late Toarcian faunas and the much more diverse Aalenian gastropod faunas in the Cleveland Basin, suggesting that there was a facies control on gastropod occurrences at that time. This is also a potential explanation for the taxonomic differences between the late Toarcian gastropod faunas in the Cleveland Basin and those in France, and northern and southern Germany