The Lower Pliocene marine gastropods of Santa Maria Island, Azores: Taxonomy and palaeobiogeographic implications.

In this work, all the Lower Pliocene gastropod assemblages of Santa Maria Island are revised. These all form part of the Touril Complex. Seventy-seven species are identified representing 61 genera. Two species are described as new: Bittium miradouroense nov. sp. and Erato mayeri nov. sp. The name Tritonium secans Bronn in Reiss 1862 is considered a junior subjective synonym of Monoplex comptus (A. Adams, 1855). Pleurotoma perturrita Bronn in Reiss 1862 is considered a junior subjective synonym of Crassopleura maravignae (Bivona, 1838). However, due to the difficulties in collecting from these deposits, this is likely to be a considerable underestimate of the original diversity of local Early Pliocene gastropod faunas. The assemblage reflects a fully tropical with mean annual sea surface temperatures (SSTs) estimated about 3.7°C to 6.3°C higher than the present-day 20.6°C, and with mean monthly SSTs ranging from 20°C to 28°C, with six months with mean SSTs over 24°C. The assemblages all represent relatively shallow water, fully saline marine environments. At genus level the assemblage is typical of that seen in the tropical Mediterranean-West African Palaeobiogeographical Province during the early Pliocene (MPPMU1; roughly equivalent to the Zanclean and earliest Piacenzian). At species level, 35% of the species taxa found in Santa Maria are also found in the Mediterranean during MPPMU1. There is a much weaker association with the northern warm temperate Pliocene Boreal-Celtic Province, with only 17% of species occurring in both. Moreover, most of those are ubiquitous European species with both wide geographic and stratigraphic distributions. The assemblage is relatively endemic (29%) suggesting that the Azorean subprovince/ecoregion, which is recognised today, was already in place in the Lower Pliocene. A small number of tonnoidean species found in Santa Maria are species known to have had an amphiatlantic distribution during the Pliocene, and for Distorsio mcgintyi Emerson & Puffer, 1953, a well-known and widely distributed tropical American Atlantic species from the Early Miocene to present-day, its presence in Santa Maria marks the most easterly range expansion for the species, as today is not found in the Azores.

Morphospecies and molecular diversity of 'lace corals': the genus Reteporella (Bryozoa: Cheilostomatida) in the central North Atlantic Azores Archipelago.

BACKGROUND: As in most bryozoans, taxonomy and systematics of species in the genus Reteporella Busk, 1884 (family Phidoloporidae) has hitherto almost exclusively been based on morphological characters. From the central North Atlantic Azores Archipelago, nine Reteporella species have historically been reported, none of which have as yet been revised. Aiming to characterise the diversity and biogeographic distribution of Azorean Reteporella species, phylogenetic reconstructions were conducted on a dataset of 103 Azorean Reteporella specimens, based on the markers cytochrome C oxidase subunit 1, small and large ribosomal RNA subunits. Morphological identification was based on scanning electron microscopy and complemented the molecular inferences. RESULTS: Our results reveal two genetically distinct Azorean Reteporella clades, paraphyletic to eastern Atlantic and Mediterranean taxa. Moreover, an overall concordance between morphological and molecular species can be shown, and the actual bryozoan diversity in the Azores is greater than previously acknowledged as the dataset comprises three historically reported species and four putative new taxa, all of which are likely to be endemic. The inclusion of Mediterranean Reteporella specimens also revealed new species in the Adriatic and Ligurian Sea, whilst the inclusion of additional phidoloporid taxa hints at the non-monophyly of the genus Reteporella. CONCLUSION: Being the first detailed genetic study on the genus Reteporella, the high divergence levels inferred within the genus Reteporella and family Phidoloporidae calls for the need of further revision. Nevertheless, the overall concordance between morphospecies and COI data suggest the potential adequacy of a 3% cut-off to distinguish Reteporella species. The discovery of new species in the remote Azores Archipelago as well as in the well-studied Mediterranean Sea indicates a general underestimation of bryozoan diversity. This study constitutes yet another example of the importance of integrative taxonomical approaches on understudied taxa, contributing to cataloguing genetic and morphological diversity.

Restructuring of the 'Macaronesia' biogeographic unit: A marine multi-taxon biogeographical approach.

The Azores, Madeira, Selvagens, Canary Islands and Cabo Verde are commonly united under the term "Macaronesia". This study investigates the coherency and validity of Macaronesia as a biogeographic unit using six marine groups with very different dispersal abilities: coastal fishes, echinoderms, gastropod molluscs, brachyuran decapod crustaceans, polychaete annelids, and macroalgae. We found no support for the current concept of Macaronesia as a coherent marine biogeographic unit. All marine groups studied suggest the exclusion of Cabo Verde from the remaining Macaronesian archipelagos and thus, Cabo Verde should be given the status of a biogeographic subprovince within the West African Transition province. We propose to redefine the Lusitanian biogeographical province, in which we include four ecoregions: the South European Atlantic Shelf, the Saharan Upwelling, the Azores, and a new ecoregion herein named Webbnesia, which comprises the archipelagos of Madeira, Selvagens and the Canary Islands.

The Echinoderm Fauna of the Azores (NE Atlantic Ocean).

In more than 150 years of research in the waters surrounding the Azores, several publications on the fauna of echinoderms of the archipelago have been produced, in the form of papers, notes, reports, reviews, and monographs. This work attempts to summarize the present knowledge on this marine group in the Azorean exclusive economic zone (i.e., waters within 200 nautical miles of the archipelago's shores). A short review of the history of the species' taxonomy is given, with key references, geographical distribution, ecology, additional notes and, when possible, figures. We herein report 172 species of echinoderms (6 crinoids, 55 ophiuroids, 45 asteroids, 36 holothurians, and 30 echinoids) from the Azores Archipelago, most of them inhabiting deep waters (>200 m). Only 29 shallow-water species were recorded locally (≤50 m depth). In general, the echinoderm species present in the Azores are characterized by a wide geographical distribution in the Atlantic Ocean. Only nine taxa (all deep-water species, >840 m) appear to be restricted to the Azorean waters. Overall, the knowledge of the echinoderm fauna of the Azores is out-dated, with many species last collected in the archipelago over 100 years ago. A recent interest in the Azorean Mid-Atlantic waters has brought oceanographic cruises back to the archipelago, thus providing new opportunities for the renewal of 150 years of echinoderm studies in the area.

Towards a 'Sea-Level Sensitive' dynamic model: impact of island ontogeny and glacio-eustasy on global patterns of marine island biogeography.

A synthetic model is presented to enlarge the evolutionary framework of the General Dynamic Model (GDM) and the Glacial Sensitive Model (GSM) of oceanic island biogeography from the terrestrial to the marine realm. The proposed 'Sea-Level Sensitive' dynamic model (SLS) of marine island biogeography integrates historical and ecological biogeography with patterns of glacio-eustasy, merging concepts from areas as diverse as taxonomy, biogeography, marine biology, volcanology, sedimentology, stratigraphy, palaeontology, geochronology and geomorphology. Fundamental to the SLS model is the dynamic variation of the littoral area of volcanic oceanic islands (defined as the area between the intertidal and the 50-m isobath) in response to sea-level oscillations driven by glacial-interglacial cycles. The following questions are considered by means of this revision: (i) what was the impact of (global) glacio-eustatic sea-level oscillations, particularly those of the Pleistocene glacial-interglacial episodes, on the littoral marine fauna and flora of volcanic oceanic islands? (ii) What are the main factors that explain the present littoral marine biodiversity on volcanic oceanic islands? (iii) How can differences in historical and ecological biogeography be reconciled, from a marine point of view? These questions are addressed by compiling the bathymetry of 11 Atlantic archipelagos/islands to obtain quantitative data regarding changes in the littoral area based on Pleistocene sea-level oscillations, from 150 thousand years ago (ka) to the present. Within the framework of a model sensitive to changing sea levels, we discuss the principal factors affecting the geographical range of marine species; the relationships between modes of larval development, dispersal strategies and geographical range; the relationships between times of speciation, modes of larval development, ecological zonation and geographical range; the influence of sea-surface temperatures and latitude on littoral marine species diversity; the effect of eustatic sea-level changes and their impact on the littoral marine biota; island marine species-area relationships; and finally, the physical effects of island ontogeny and its associated submarine topography and marine substrate on littoral biota. Based on the SLS dynamic model, we offer a number of predictions for tropical, subtropical and temperate volcanic oceanic islands on how rates of immigration, colonization, in-situ speciation, local disappearance, and extinction interact and affect the marine biodiversity around islands during glacials and interglacials, thus allowing future testing of the theory.

Global change impacts on large-scale biogeographic patterns of marine organisms on Atlantic oceanic islands.

Past climate changes provide important clues for advancement of studies on current global change biology. We have tested large-scale biogeographic patterns through four marine groups from twelve Atlantic Ocean archipelagos and searched for patterns between species richness/endemism and littoral area, age, isolation, latitude and mean annual sea-surface temperatures. Species richness is strongly correlated with littoral area. Two reinforcing effects take place during glacial episodes: i) species richness is expected to decrease (in comparison with interglacial periods) due to the local disappearance of sandy/muddy-associated species; ii) because littoral area is minimal during glacial episodes, area per se induces a decrease on species richness (by extirpation/extinction of marine species) as well as affecting speciation rates. Maximum speciation rates are expected to occur during the interglacial periods, whereas immigration rates are expected to be higher at the LGM. Finally, sea-level changes are a paramount factor influencing marine biodiversity of animals and plants living on oceanic islands.

New species of Rissoidae (Mollusca, Gastropoda) from the Archipelago of the Azores (northeast Atlantic) with an updated regional checklist for the family.

Four new species of shallow-water marine gastropods belonging to the family Rissoidae are described from the Archipelago of the Azores: Setiaalexandrae sp. n., Setiaermelindoi sp. n., Setianetoae sp. n., and Manzoniamartinsi sp. n. These novelties increase the regional rissoid fauna to 39 species, of which 29 live in shallow-water habitats. A list of the species of Rissoidae from the Azores is presented based on data from the literature and new material examined.

New records for the shallow-water chiton fauna (Mollusca, Polyplacophora) of the Azores (NE Atlantic).

Published records, original data from recent field work on all of the islands of the Azores (NE Atlantic), and a revision of the entire mollusc collection deposited in the Department of Biology of the University of the Azores (DBUA) were used to compile a checklist of the shallow-water Polyplacophora of the Azores. Lepidochitona cf. canariensis and Tonicella rubra are reported for the first time for this archipelago, increasing the recorded Azorean fauna to seven species.

Patterns of diversity of the Rissoidae (Mollusca: Gastropoda) in the Atlantic and the Mediterranean region.

The geographical distribution of the Rissoidae in the Atlantic Ocean and Mediterranean Sea was compiled and is up-to-date until July 2011. All species were classified according to their mode of larval development (planktotrophic and nonplanktotrophic), and bathymetrical zonation (shallow species--those living between the intertidal and 50 m depth, and deep species--those usually living below 50 m depth). 542 species of Rissoidae are presently reported to the Atlantic Ocean and the Mediterranean Sea, belonging to 33 genera. The Mediterranean Sea is the most diverse site, followed by Canary Islands, Caribbean, Portugal, and Cape Verde. The Mediterranean and Cape Verde Islands are the sites with higher numbers of endemic species, with predominance of Alvania spp. in the first site, and of Alvania and Schwartziella at Cape Verde. In spite of the large number of rissoids at Madeira archipelago, a large number of species are shared with Canaries, Selvagens, and the Azores, thus only about 8% are endemic to the Madeira archipelago. Most of the 542-rissoid species that live in the Atlantic and in the Mediterranean are shallow species (323), 110 are considered as deep species, and 23 species are reported in both shallow and deep waters. There is a predominance of nonplanktotrophs in islands, seamounts, and at high and medium latitudes. This pattern is particularly evident in the genera Crisilla, Manzonia, Onoba, Porosalvania, Schwartziella, and Setia. Planktotrophic species are more abundant in the eastern Atlantic and in the Mediterranean Sea. The results of the analysis of the probable directions of faunal flows support the patterns found by both the Parsimony Analysis of Endemicity and the geographical distribution. Four main source areas for rissoids emerge: Mediterranean, Caribbean, Canaries/Madeira archipelagos, and the Cape Verde archipelago. We must stress the high percentage of endemics that occurs in the isolated islands of Saint Helena, Tristan da Cunha, Cape Verde archipelago and also the Azores, thus reinforcing the legislative protective actions that the local governments have implemented in these islands during the recent years.