PDF - MPB - Marine PalaeoBiogeography
Transcrição
Bull. Soc. géol. Fr., 2009, t. 180, no 4, pp. 295-307 How did they get here? The biogeography of the marine molluscs of the Azores SÉRGIO P. ÁVILA1,2,3, CARLOS MARQUES DA SILVA4, RALF SCHIEBEL5, FABBRIZZIO CECCA6, THIERRY BACKELJAU7 and ANTÓNIO M. DE FRIAS MARTINS1,3 Key-words. – Pleistocene, Recent, Mollusca, Azores, routes of dispersal, Palaeobiogeography. Abstract. – The geographical location of the Azores, midway between Europe and America, poses problems relative to their colonization and the biogeographic affinity of the biota presently living there. In the way of the Gulf Stream, originating off American shores, the Azorean biota, marine and terrestrial alike is predominantly European. To explain this distributional paradigm the present study investigates the Neogene fossil record of Santa Maria, Azores in order to establish the biogeographical relationships of the Pleistocene to Recent littoral molluscan fauna of this archipelago. The bulk of the Azorean malacofauna, both in the Pleistocene (71.3%) and in Recent times (75.6%) is biogeographically related with the eastern Atlantic, and that the Pleistocene (Eemian) fossil fauna is basically the same as the Recent fauna, with a few losses of tropical species and of shallow water bivalves associated to fine sand substrates. It is hypothesized that during Pleistocene glacial-interglacial cycles, short-duration events have occurred during which short-lived oceanic currents must have been established, especially during or shortly after glacial terminations. During these short-term events, the arrival of species to the Azores may have been increased and facilitated by temporary sea-surface currents that no longer exist now. Probable routes of dispersal to the archipelago of the Azores are also discussed, as well as the possible influence of the Pleistocene glaciations in the shallow water marine molluscs of these islands. Comment sont-ils arrivés ici ? Biogéographie des mollusques marins des Azores Mots-clés. – Pléistocène, Actuel, Mollusques, Azores, Chemins de dispersion, Paléobiogéographie Résumé. – La localisation géographique des Azores, à mi-chemin entre l’Europe et l’Amérique, pose des problèmes relatifs à leur colonisation et les affinités biogéographiques des biotas vivant là actuellement. Sur le tracé du Gulf Stream, qui prend naissance sur les côtes américaines, les biotas azoréens, aussi bien marins que continentaux sont principalement européens. Pour expliquer ce paradigme de distribution, la présente étude porte sur l’enregistrement fossile néogène de Santa Maria, Azores, pour établir les relations biogéographiques des faunes de mollusques littoraux du Pléistocène à l’Actuel de cet archipel. La majeure partie de la malacofaune azoréenne, à la fois au Pléistocène (71.3 %) et à l’Actuel (75.6 %) est biogéographiquement en relation avec l’Est Atlantique, et les faunes fossiles du Pléistocène (Eemien) sont dans l’ensemble les mêmes que celles de l’Actuel avec des pertes d’espèces tropicales et de bivalves d’eau peu profondes associées aux substrats de sables fins. L’hypothèse est émise que durant les cycles glaciaire-interglaciaire du Pléistocène, de courts événements ont eu lieu durant lesquels des courants océaniques temporaires ont du s’établir, spécialement durant et peu de temps après les fins de glaciation. Durant ces événements courts, les arrivées d’espèces aux Azores ont pu augmenter et être facilitées par des courants de surface temporaires qui n’existent plus maintenant. Les chemins de dispersions probables vers l’archipel des Azores sont également discutés, ainsi que l’influence possible des glaciations pléistocènes sur les mollusques d’eaux profondes de ces îles. INTRODUCTION It is known since the 19th century that the marine fauna of the Northeast Atlantic archipelagos of Macaronesia (Azores, Madeira, Selvagens and Canaries) has very diverse biogeo- graphical affinities [MacAndrew, 1854; Ávila, 2000a, 2005; Morton and Britton, 2000; Wirtz et al., 2003]. Due to its geographical location, the archipelago of the Azores is of crucial importance to infer colonization patterns, to establish the biogeographic historical relationships with related biotas and 1. Departamento de Biologia, Universidade dos Açores, 9501-801 Ponta Delgada, Azores, Portugal 2. Centro do IMAR da Universidade dos Açores, 9901-862 Horta, Azores, Portugal 3. MPB, Marine Palaeobiogeography Working Group of the University of the Azores, Rua da Mãe de Deus, 9501-801 Ponta Delgada, Azores, Portugal 4. Departamento e Centro de Geologia, Faculdade de Ciências, Universidade de Lisboa, Bloco C6, Campo Grande, 1749-016 Lisboa, Portugal 5. School of Earth and Ocean Science, National Oceanography Centre, Southampton, European Way, Southampton SO14 3ZH, United Kingdom 6. Université “Pierre et Marie Curie” – Paris VI, CNRS-UMR 5143 “Paléobiodiversité et Paléoenvironnements”, Tour 56-46, 5ème étage, case 104, 4, place Jussieu, 75252 Paris cédex 05, France 7. Royal Belgian Institute of Natural Sciences, Department of Invertebrates, Malacology Section, Vautierstraat 29, 1000 Brussels, Belgium Manuscrit déposé le 30 novembre 2007 ; accepté après révision le 5 mars 2009. Bull. Soc. géol. Fr., 2009, no 4 296 ÁVILA S. P. et al. to propose hypotheses on processes of dispersal, colonization and speciation that occurred in these insular habitats. In the Azores, Santa Maria Island is the only place where both marine and terrestrial Neogene fossils are found. Since the pioneer work of Mayer [1864], most of the studies hitherto have focused on the Miocene-Pliocene marine taxa that are abundant in several outcrops [see Ávila et al., 2002 for a list of references]. Therefore attention has recently moved to the Pleistocene marine molluscs of Santa Maria [García-Talavera, 1990; Callapez and Soares, 2000; Ávila et al., 2002]. Data about the Pleistocene molluscs from Santa Maria, herein reported, will be used to compare and discuss the Pleistocene and the Recent biogeographical relationships of the shallow water (< 50 m) Azorean marine molluscs. Probable routes of dispersal to the archipelago of the Azores, as well as the influence of the Pleistocene glaciation-interglaciation cycles are also discussed. MATERIALS AND METHODS Two Pleistocene marine fossiliferous outcrops are known at Santa Maria : Lagoinhas, located in the north coast of the island at +7.4 m above present sea-level and with a lateral extension of less than 100 m; and Prainha, near the beach of Praia Formosa, about 5 km east of Vila do Porto, with fossiliferous layers that extend for 800 m along the seashore at the present height of +2 to +4 m (fig. 1). Ávila et al. [2002] detailed and discussed the stratigraphic succession established by Zbyszewsky and Ferreira [1961, 1962] and by García-Talavera [1990] for the outcrop of Prainha, and by Callapez and Soares [2000] for Lagoinhas. Ávila et al. [2008a] have recently dated the basal sequence at Prainha as corresponding to the Marine Oxygen Isotope Substage 5e (MIS5e) (117-130 m.y.). One hundred and three bulk samples were collected at Prainha and two samples at Lagoinhas from February 2000 to June 2002 [Ávila et al., 2002]. New fossil material was collected at the Lagoinhas outcrop in February 2003. Ten bulk samples of sandy fossiliferous sediments (1 kg each) were washed through a 0.5 mm mesh sieve. All mollusc remains found were sorted and identified. Recent collecting from the fossiliferous strata of Prainha and Lagoinhas during the 2nd and 3rd Workshops “Palaeontology in Atlantic Islands” (2005 and 2006) provided additional material. The samples are deposited in the fossil collection of the Department of Biology of the University of the Azores (DBUA-F) (the complete list of the samples is available at http://www.uac.pt/~fosseis/DBUA-F.pdf). The mode of larval development of the gastropods represented in the analyzed samples was inferred trough SEM images of the protoconch morphology [Jablonski and Lutz, 1980]. This procedure was extended to most of the micro-molluscs shells obtained. The palaeobiogeographical relationships of the Santa Maria Pleistocene shallow-water marine molluscs were established by comparing the Prainha and Lagoinhas database with data from the western Atlantic (Atlantic shores of Canada, U.S.A and the Caribbean), eastern Atlantic (Atlantic shores of Europe and west Africa), the Mediterranean, and the archipelagos of Macaronesia [for sources of data see Ávila, 2000a, 2005]. Bull. Soc. géol. Fr., 2009, no 4 Abbreviations used in text DBUA-F – reference collection of the fossil marine molluscs of the Azores (Department of Biology of the University of the Azores, Ponta Delgada, São Miguel Island, Azores) (http://www.uac.pt/~fosseis/DBUA-F.pdf). DBUA – reference collection of the Recent marine molluscs of the Azores (Department of Biology of the University of the Azores, Ponta Delgada, São Miguel Island, Azores) (http://www.uac.pt/~fosseis/DBUA.pdf). RESULTS Ávila et al. [2002] reported 95 species from the outcrops of Prainha and Lagoinhas (80 Gastropoda and 15 Bivalvia) of which six were considered as dubious records (5 Gastropoda and 1 Bivalvia). The records of Tricolia pullus azorica DAUTZENBERG, 1889 and of Bulla amygdala DILLWYN, 1817 (=B. mabillei LOCARD, 1897) previously reported by Zbyszewsly et al. [1961] and García-Talavera [1990], but not found by Ávila et al. [2002] are now confirmed. Thirteen new records, some illustrated in figures 2-4 (three found at Prainha and the remaining 10 at Lagoinhas) increase the number of species to 108 (92 Gastropoda and 16 Bivalvia), of which seven gastropods are considered dubious records (their identification needs confirmation): Rissoa similis SCACCHI, 1836; Rissoa ventricosa DESMAREST, 1814; Alvania canariensis (d’ORBIGNY, 1840); Alvania pagodula (BUCQUOY, DAUTZENBERG and DOLLFUS, 1884); Pusillina philippi (ARADAS and MAGGIORE, 1844); Pusillina radiata (PHILIPPI, 1836) and Gibbula cineraria (LINNAEUS, 1758). In particular, Rissoa ventricosa and Pusillina radiata, both reported to the Prainha outcrop by García-Talavera [1990], are most likely to be misidentifications, as these are species with a strong connection to seagrasses beds, which are unlikely to have occurred in the Azores (in the present, there are also no seagrasses beds off the Azores). Thus, 101 is the updated number of species currently known from the Pleistocene of Santa Maria Island (fig. 5, tabl. I). The new records are: Cerithiopsis minima (BRUSINA, 1865); Littorina saxatilis (OLIVI, 1792); Alvania abstersa VAN DER LINDEN and VAN AARTSEN 1994; Alvania formicarum GOFAS, 1989; Pusillina inconspicua (ALDER, 1844); Nassarius incrassatus (STRØM, 1768); Columbella adansoni MENKE, 1853; Philippia hybrida (LINNAEUS, 1758); Odostomella doliolum (PHILIPPI, 1844); Odostomia duureni AARTSEN, GITTENBERGER and GOUD, 1998; Odostomia cf. kuiperi AARTSEN, GITTENBERGER and GOUD, 1998 and the bivalves Striarca lactea (LINNAEUS, 1758) and Pinna rudis LINNAEUS, 1758 (tabl. I). Seventeen, out of the 101 Pleistocene species presently reported from Santa Maria Island, are endemic to the Azores, four are widespread in the Macaronesian archipelagos and only 11 occur in the western Atlantic, most of them, in the Caribbean area. In contrast, 71 species that were found at Prainha and Lagoinhas also occur in the Pleistocene deposits from the eastern Atlantic/Mediterranean European shores (tabl. I). DISCUSSION Biogeographical relationships of the Pleistocene (Eemian) and Recent Azorean malacofauna The location of the Azores in the middle of the north Atlantic renders this archipelago susceptible to colonization by THE BIOGEOGRAPHY OF THE MARINE MOLLUSCS OF THE AZORES TABLE I. – Checklist and geographical distribution of the 101 species reported to the Pleistocene outcrops of Prainha and Lagoinhas (Santa Maria Island, Azores). AZO end – endemic species to the Azores. A – species/taxa collected by the authors; B – species/taxa reported but not collected by the authors. TABL. I. – Liste et distribution géographique des 101 espèces reconnues dans les affleurements du Pléistocène de Prainha et de Lagoinhas (Île de Santa Maria, Azores). AZO end – espèces endémiques des Azores. A – espèces/taxa récoltés par les auteurs ; B – espèces/taxa reportés ici mais non récoltés par les auteurs. 297 TABLE I. – (following) TABL. 1. – (suite) species from both sides of the Atlantic. Several authors concluded that, notwithstanding the fact that the present day prevailing currents in the Azores region would favour colonization from the western Atlantic, most of the recent littoral marine Azorean molluscs are biogeographically related with the eastern Atlantic shores [Mac Andrew, 1854; Ávila, 2000a, 2005; Ávila and Albergaria, 2002]. Even considering only the Azorean endemic species, with the Rissoidae accounting for almost half of the total number of endemisms [Ávila, 2000b, 2005], the present benthic littoral malacofauna of the Azores is clearly dominated by species in common to European and/or Madeira and Canary Islands coasts. Of the 299 (Recent) species of molluscs reported from the Azores by Ávila [2005], 39 (13.0%) occur also at the western Atlantic, whereas of the 101 taxa reported from Pleistocene sediments of Santa Maria, 11 species were present in the western Atlantic (10.9%) (tabl. II). The bulk of the Azorean malacofauna, both in the Pleistocene (71.3%) and in Recent times (75.6%) is biogeographically related with the eastern Atlantic. In the present time, Stramonita haemastoma haemastoma (LINNAEUS, 1766), Charonia variegata (LAMARCK, 1816), Phalium granulatum (BÖRN, 1778), Conus ermineus BÖRN, 1778 and Polynices lacteus (GUILDING, 1834) are amphi-Atlantic species [García-Talavera, 1981] as well as Skeneopsis planorbis (O. FABRICIUS, 1780). Laursen [1981] reported the larvae of Polynices lacteus TABLE II. – Pleistocene and Recent biogeographical relationships of the mollusc fauna from Prainha and Lagoinhas (Santa Maria, Azores). TABL. II. – Relations biogéographiques pléistocènes et actuelles des faunes de mollusques de Prainha et Lagoinhas (Santa Maria, Azores). Bull. Soc. géol. Fr., 2009, no 4 298 ÁVILA S. P. et al. FIG. 1. – Geographical location of Santa Maria Island in the Azores archipelago (A) and location of the sampling sites, Prainha and Lagoinhas (B). (c) Secção de Geografia, Universidade dos Açores. FIG.1. – Localisation géographique de l’île de Santa Maria dans l’archipel des Azores (A) et localisation des sites d’échantillonnage, Prainha et Lagoinhas (B). (c) Secção de Geografia, Universidade dos Açores. in the waters surrounding the Azores and, although Morton et al. [1998] reported the adults of this species to the Azores, the authors have stated that it was erroneous information (in litt., 2004). The largest fossil specimen of Polynices lacteus collected at Prainha is 1.8 x 1.4 cm but Ávila et al. [2002] questioned the existence of viable recent populations of this species in the Azores. In fact, more than 800 lots of the DBUA collection (Recent shallow-water marine molluscs of the Azores) were surveyed and not a single specimen of this conspicuous gastropod was found [Ávila et al., 1998, 2000a, 2000b; Ávila, 2005]. Except for the thermophilic species (the so-called “Strombus accompanying fauna”) that presumably reached the Azores during the transition from the Pleistocene marine isotope stage MIS6 to the MIS5e or shortly after that (tabl. III) due to the higher sea-surface temperatures (SST), the molluscan assemblages found at Prainha and Lagoinhas are very similar to those described by Ávila [2000a, 2003] Bull. Soc. géol. Fr., 2009, no 4 and Ávila et al. [2005] for the Recent littoral marine molluscs of the Azores, with a high number of Azorean species that presently occur also at the Mediterranean, Portugal, Madeira and the Canary Islands. This pattern of Recent biogeographical relationships is also observed in other well studied organisms in the Azores : Porifera, Cnidaria (Anthozoa), Annelida, Arthropoda (Crustacea), Echinodermata, Pisces [for a review and references see Morton and Britton, 2000] and it is not consistent with the present pattern of sea-surface circulation of the North Atlantic [Käse and Siedler, 1982; Gould, 1985; Kleine and Siedler, 1989; Alves and Simões, 1997; Alves and Verdière, 1999; Alves et al., 2002; Schiebel et al., 2002], thus a mechanism is needed to explain this apparent contradiction. Previous authors [Mayer, 1864; Cotter, 1888-1892; Friedlander, 1929; Agostinho, 1937; Berthois, 1950, 1951, 1953; Ferreira, 1952, 1955; Krejci-Graff et al., 1958; Zbyszewski et al., 1961; Zbyszewski and Ferreira, 1961, 1962] THE BIOGEOGRAPHY OF THE MARINE MOLLUSCS OF THE AZORES TABLE III. – Stratigraphic distribution and mode of larval development (p – planktotrophic; np – non-planktotrophic) of the thermophilous species collected in the Pleistocene of Prainha and Lagoinhas (Santa Maria Island, Azores) and that subsequently locally disappeared from the Azores. The stratigraphy of the outcrops follows Ávila et al. [2002]: a basal strongly cemented calcareous conglomerate (unit A1), overlaid by a calcareous algae mat (unit A2) and above a non-depositional hiatus surface, a sandy beach deposit (unit B1). TABL. III. – Distribution stratigraphique et mode de développement des larves (p – planctotrophique ; np – non planctotrophique) des espèces thermophiliques récoltées dans le Pléistocène de Prainha et Lagoinhas (Île de Santa Maria, Azores) et qui disparaissent ensuite localement des Azores. Stratigraphie des affleurements d’après Ávila et al. [2002] : à la base un conglomérat calcaire fortement cimenté (unité A1), surmonté par un tapis algaire calcaire (unité A2) et au-dessus une surface de hiatus sans dépôt, un dépôt de sable de plage (unité B1). all agreed that also the Miocene to Pliocene mollusc fauna from Santa Maria has eastern Atlantic affinities. Preliminary results from our work at Santa Maria since 1998 show that more than 96% of the Miocene-Pliocene molluscs of Santa Maria are biogeographically related with the eastern Atlantic. Geological and oceanographical data The Azores is an archipelago of about 8 Ma (Santa Maria Island) [Madeira, 1986; Serralheiro et al., 1987; Serralheiro and Madeira, 1990; Serralheiro, 2003]. As volcanic oceanic islands, these once empty habitats had to be colonized from elsewhere. The nearest colonizing source is the Madeira archipelago, presently at about 900 km southeast, but other plausible sources are the Iberian and West European Atlantic shores, the Mediterranean, the western African shores, the Canary Islands and also the Caribbean region. The general pattern of oceanic circulation in the Northern Atlantic has been roughly the same since the closure of the Isthmus of Panama, a complex, slow and progressive process that begun about 13 Ma and finished with the complete separation between the Pacific and the Atlantic between 3.1 and 2.7 Ma ago [Coates and Obando, 1996; Haug and Tiedermann, 1998]. Intermittent connections between those oceans may have persisted into the Late Pliocene and possibly during Early and Middle Pleistocene interglacial periods [Beu, 2001; Landau et al., 2007]. The Gulf Stream is the major hydrographical feature influencing the climate in the Azores region. During glacial periods this large sea-surface current was stronger than at present, with both higher velocity and volume, due to the latitudinal descent of the Polar Front [Crowley, 1981; Wunsch, 2003]. Moreover, wind-velocities were higher than nowadays [Crowley and North, 1991]. As a consequence, during the glacial episodes, the probability of western Atlantic specimens (larvae and/or juveniles/adults) reaching the Azores would be 299 higher (warm-water Caribbean species, for instance). However, for the establishment of viable, reproductive populations in the Azores Islands, this would require the existence of optimal SSTs both for the survival of larvae and, later, for the accomplishment of successful reproductive phases [Raffi, 1986]. Should these optimal thermal conditions not exist the newly arrived molluscs would simply originate “pseudopopulations” in the sense of Bouchet and Taviani [1992] or “dependent populations” [Boehlert et al., 1994], the maintenance of which would rely solely on the regular arrival of new colonizers. How to reach an oceanic island? Processes of dispersion The dispersion of many benthic marine invertebrates is achieved by means of pelagic larvae [Strathman, 1974], which are dependent on the main sea-surface currents. Other plausible means of dispersion are by foresy, that is, transported by birds attached to their feathers, a common feature in the case of some intertidal molluscs nowadays present in the Azores [Ávila, 2000a], by rafts of egg-masses, juveniles or adults of small-sized species attached to seaweeds [Highsmith, 1985; Ávila, 2006], to carapaces of marine turtles [Frazier et al., 1985], pumice [Jokiel, 1984], logs, and other suitable floating materials [Jokiel, 1990]. Gittenberger et al. [2006] have recently shown that terrestrial snails were transported by birds as far as from Europe to the Azores islands. Birds are frequently blown off course by strong winds. Strong easterly winds originating from northwestern Africa and extending over the Atlantic as far as the Caribbean Sea are a common feature, and are recorded by the presence of Saharan dust [Chester, 1971; Reis et al., 2002; Petit et al., 2005]. It is therefore likely that at least some of the intertidal species of the malacofauna of Santa Maria (about 2% of the total Pleistocene species; Ávila, unpubl. data) have been introduced by birds, which have been flown or blown over to the Azores from the western shores of Europe. However, and with the possible exception of some of the intertidal species, all of the others certainly reached these islands by larval dispersion or by rafts. As the Azores are not at midway between Europe and America, but closer to Europe and Africa, in spite of the Gulf Stream, it is more likely that larvae can reach the Azores more easily from east (via the Macaronesian bridge, as discussed below) than from the Caribbean. Glacial terminations During Pleistocene glacial-interglacial cycles, short-duration events have occurred during which short-lived oceanic currents must have been established, especially during and/or shortly after glacial terminations. Fifteen such cycles have occurred during the last million years [Wilson et al., 2000]. The penultimate interglaciation begun about 130,000 y ago and was preceded by a rapid glacial termination (Termination II, 132,000-126,000), a 6,000 y event during which sea level rose by several tens of meters [Broecker and Henderson, 1998; Waelbroeck et al., 2002]. During Termination I (19,500-6,000 y) sea level rose by 120-130 m [Yolohama et al., 2000; Lambeck and Chappel, 2001; Clark and Mix, 2002]. During these short-term events, the arrival of species to the Azores (especially from the east Atlantic) due to range expansion processes may have been increased and facilitated by temporary sea Bull. Soc. géol. Fr., 2009, no 4 300 ÁVILA S. P. et al. surface currents that no longer exist now. This possibility is supported by Gerber et al. [1989] data, who studied several Pleistocene outcrops from Porto Santo Island (Madeira archipelago) of similar age to that of the Prainha and Lagoinhas mollusc assemblages, and who reported Polynices lacteus, Cantharus variegatus (GRAY, 1839) and one Conus species, all of them having locally disappeared from Madeira archipelago. At Tenerife (Canary Islands) the Pleistocene stratigraphic sequence of Tachero presents similarities in both age and taxonomic composition, with those of Prainha and Lagoinhas in the Azores [García-Talavera et al., 1978; 2006, pers. comm]. Both show a biogenic limestone bed (40 cm thick at Tachero, formed mostly by remains of the Melobesia calcareous algae) at the base of the sequence, followed by a sandy layer. Of the 94 species reported by García-Talavera et al. [1978 : 99] for Tachero (72 Gastropoda, 21 Bivalvia and one Cephalopoda), 16 also occur at Prainha : 13 Gastropoda and 3 Bivalvia. Most of the gastropods identified have a planktotrophic larval development (tabl. IV). FIG. 2. – A, B: Alvania abstersa (DBUA-F 149/170-5); C Alvania abstersa (DBUA-F 149/170-4): D-F: Alvania formicarum DBUA-F 2/102-1; G: Pusillina inconspicua (DBUA-F 149/171-2); H, I: Pusillina inconspicua (DBUA-F 149/171-1); J-L: Odostomella doliolum (DBUA-F149/172-1). FIG. 2. – A, B : Alvania abstersa (DBUA-F 149/170-5) ; C : Alvania abstersa (DBUA-F 149/170-4) : D-F : Alvania formicarum DBUA-F 2/102-1 ; G : Pusillina inconspicua (DBUA-F 149/171-2) ; H, I : Pusillina inconspicua (DBUA-F 149/171-1) ; J-L : Odostomella doliolum (DBUA-F149/172-1). Bull. Soc. géol. Fr., 2009, no 4 THE BIOGEOGRAPHY OF THE MARINE MOLLUSCS OF THE AZORES Modes of larval development and dispersal ability It is usually assumed by marine biologists that gastropods with a planktotrophic larval development show wider geographical ranges than those with a non-planktotrophic development [Scheltema, 1971, 1977, 1986a, 1986b, 1989; Jablonski and Lutz, 1980, 1983]. Some notorious exceptions are known – e.g.: Lasaea adansoni [GMELIN, 1791], a brooding bivalve [Ó Foighil, 1989], and temperate intertidal small-sized gastropods with non-planktotrophic development [Ávila, 2005, 2006; Ávila et al., 2005], that disperse attached to drifting seaweeds – but, in average conditions, the rule holds for most of marine molluscs. Thus, in oceanic islands geographically located far away from source populations, we would expect to find a high proportion of species with a planktotrophic larval development (p), relative to the number of non-planktotrophic ones (np), and that is precisely what happens with the Recent molluscs of the Azores. From a total of 146 Prosobranchs presently reported to these islands, 62 (42.5%) are planktotrophic species, 54 (37.0%) are non-planktotrophic species and it was not possible yet to determine the mode of larval development for the remaining 30 species (20.5%) (Ávila, unpub. data). Omitting the endemic stock (27 np-species and 2 p-species) and the 30 species with undetermined mode of development, the proportions are 69.0% of planktotrophic species and 31.0% of non-planktotrophic species. However, that is not the case with the species that locally disappeared from Santa Maria, as a consequence of the last glaciation (tabl. V). We must stress that these thermophilic species could not occur in the Azores during MIS6 (that is, before the beginning of Termination II), therefore they must have arrived to the Azores during or shortly before MIS5e. As none of the different modes of development (p or np) is apparently favoured (53.8% of p-species versus 46.2% of np-species), in contrast with the figures for the Recent malacofauna, where an excess of p-developers occurs (69.0%), relative to np-developers (31.0%), this seems to support the idea of a short-temporal window assisting the TABL. IV. – Mode of larval development (p – planktotrophic; np – non-planktotrophic) of the Pleistocene gastropod species collected at Tachero (Tenerife, Canary Islands) by García-Talavera et al. [1978] and also reported to the Pleistocene of Santa Maria Island (Azores) by Ávila et al. [2002]. TABL. IV. – Mode de développement des larves (p – planctotrophique ; np – non planctotrophique) des espèces de gastéropodes pléistocènes collectés à Tachero (Tenerife, Îles Canaries) par García-Talavera et al. [1978] et également retrouvées sur l’Île de Santa Maria (Azores) par Ávila et al. [2002]. 301 TABLE V. – Mode of larval development (p – planktotrophic; np – non-planktotrophic; ? – probable mode of larval development) of the Pleistocene gastropod species reported to Santa Maria Island (Azores) that locally disappeared during the last glaciation. TABL. V. – Mode de développement des larves (p – planctotrophique ; np – non planctotrophique; ? – mode développement probable des larves) des espèces pléistocènes de gastéropodes pléistocènes signalées dans l’Île de Santa Maria (Azores) et qui disparaissent localement durant la dernière glaciation. arrival of both p and np-developers to the Azores. During this time frame, short-lived oceanic currents (different from the ones that exist in the present times) must have been established, especially during or shortly after glacial Terminations, promoting the dispersal of species to the Azores. If the direction of these currents was similar to the present ones, we would expect exactly the reverse: i.e. short time dramatically favouring the more active p-colonisers, and longer time-windows allowing progressively also the less efficient np- np-developers. Thus, the expected likelihoods will dramatically change, if the currents are in the direction of the Azores. In this case, the proportion “np/p” will increase, and that is precisely what we see in the fossil record of Santa Maria. TABLE VI. – Approximate surface area (km2) of the islands of the Azores, Madeira and Canary Islands (18,000 y) and in the present. * The former island of Mahan is equivalent nowadays to the islands of Fuerteventura and Lanzarote, and the islets of La Graciosa and Los Lobos [García-Talavera, 1999; Ávila, 2005]. TABL. VI. – Surface approximative (km2) des îles des Azores, de Madère et des Canaries il y a 18,000 ans et actuellement. * L’ancienne île de Mahan est l’équivalent actuel des îles de Fuerteventura et de Lanzarote et des îlots de La Graciosa et Los Lobos [García-Talavera, 1999 ; Ávila, 2005]. Bull. Soc. géol. Fr., 2009, no 4 302 ÁVILA S. P. et al. FIG. 3. – A : Littorina saxatilis (DBUA-F 149/170-3); B, C: Nassarius incrassatus (DBUA-F 149/170-2); D: Bulla mabillei (DBUA-F 148); E, F: Odostomia cf. kuiperi (DBUA-F 149/171-4); G-J: Philippia hybrida (DBUA-F 137/156-1). FIG. 3. – A : Littorina saxatilis (DBUA-F 149/170-3) ; B, C : Nassarius incrassatus (DBUA-F 149/170-2) ; D : Bulla mabillei (DBUA-F 148) ; E, F : Odostomia cf. kuiperi (DBUA-F 149/171-4) ; G-J : Philippia hybrida (DBUA-F 137/156-1). Ávila et al. [2002; 2008b] have shown that, besides the thermophilic species, only those species of littoral endobenthic bivalves usually associated to fine sandy substrata, such as Ensis minor (CHENU, 1843) and Lucinella divaricata (LINNAEUS, 1758), did locally disappear from Santa Maria Island during the last glaciation. The endemic Azorean species (where the minute Rissoidae account for almost half) were not affected by the drop of SSTs and the associated sea level fall [Ávila, 2005]. Bull. Soc. géol. Fr., 2009, no 4 At the peak of the last glaciation, sea level was about 120-130 m lower than at present [Lambeck and Chappel, 2001]. As a consequence, the area of the islands of the Macaronesian archipelagos was larger than today (tabl. VI) and a number of seamounts nowadays located between the southwest of Iberia and Madeira were true islands (fig. 6). The distance between each of these palaeoislands located between Madeira and Iberia would be of only 200-300 km. Therefore, these islands may have played an important role THE BIOGEOGRAPHY OF THE MARINE MOLLUSCS OF THE AZORES 303 FIG. 4. – A: Sinezona cingulata (DBUA-F 139/126-2); B: Pinna rudis DBUA-F 147 (96 x 66 mm); C, D: Odostomia duureni (DBUA-F 137/151-3); E: Striarca lactea (teratological specimen) (DBUA-F 137/160-1); F: Conus cf miruchae DBUA-F 89); G: Trachypollia nodulosa (DBUA-F 3/115-1); F: Odostomia (DBUA-F 139/126-5); H, I: Auriculinella bidentata (DBUA-F 149/171-3); J: Pedipes pedipes (DBUA-F2/114-1). FIG. 4. – A : Sinezona cingulata (DBUA-F 139/126-2) ; B : Pinna rudis DBUA-F 147 (96 x 66 mm) ; C, D : Odostomia duureni (DBUA-F 137/151-3) ; E : Striarca lactea (spécimen) (DBUA-F 137/160-1) ; F : Conus cf miruchae (DBUA-F 89) ; G : Trachypollia nodulosa (DBUA-F 3/115-1) ; F : Odostomia (DBUA-F 139/126-5) ; H, I : Auriculinella bidentata (DBUA-F 149/171-3) ; J : Pedipes pedipes (DBUA-F2/114-1). in the processes of dispersion, especially of the intertidal and shallow water molluscs. Thus an increase in the number of successful migrants of littoral species from Iberian shores towards Madeira during glacial periods is expectable, taking advantage on the smaller distances and favourable currents and winds. By contrast, the fossil record of Santa Maria shows that during interglacial periods, warm-water species from Caribbean and African shores did reach the Azores, e.g. several species of Conus [Ávila et al., 2002; Ávila, 2005]. It seems to us that the predominant routes will be different during glacial and interglacial periods. The similarities Bull. Soc. géol. Fr., 2009, no 4 304 ÁVILA S. P. et al. FIG. 5. – Cumulative number of species correctly reported to the Pleistocene outcrops of Prainha and Lagoinhas (Santa Maria Island, Azores). FIG. 5. – Nombre cumulé d’espèces avec enregistrements validés dans les affleurements pléistocènes de Prainha et Lagoinhas (Île Santa Maria, Azores). found in the fossil record of Santa Maria (Azores) and Porto Santo (Madeira) (interglacial period, both with a MIS5e attributed age) seems to point to a colonization of the Azores via Madeira. However, this is not consistent with recent DNA investigations, which indicate a younger connection between Azores and Portugal and an ancient connection between the Azores and Madeira [Gonçalves et al., 2000; Ó Foighil et al., 2001]. CONCLUSIONS Prior to the final closure of the Isthmus of Panama and the development of the Gulf Stream, the main sea surface currents in the Atlantic Ocean had an east-west predominant direction; therefore, it is expectable that, before the onset of FIG. 6. – Oceanic islands 18,000 y [adapted from García-Talavera, 1999]. FIG. 6. – Iles océaniques il y a 18 000 ans [adapté de García-Talavera, 1999]. Bull. Soc. géol. Fr., 2009, no 4 the Pleistocene glaciations, European species more easily reached the Azores region than they do today. The eastern Atlantic biogeographical relationships of the Azorean fauna that we see nowadays are precisely the remnants of that ancient signal. Only after the installation of the Gulf Stream and its associated system of currents, was possible the arrival to the Azores of species from the Caribbean. This is the reason why, from more than 130 species of molluscs reported to the late Miocene of the Azores, only a few species are also reported from the Caribbean; all others are reported from Miocene outcrops of Europe and western Africa (Ávila et al., unpubl. data), whereas in the Pleistocene and in the Recent, the percentage of Azorean species of molluscs that are reported from the Caribbean is much higher (11 and 13%, respectively) (tabl. II). At the peak of the last glaciation, the area of the islands of the Macaronesian archipelagos was larger than today and a number of seamounts nowadays located between the southwest of Iberia and Madeira were true islands, probably playing an important role in the processes of dispersion, especially of the intertidal and shallow water molluscs. An increase in the number of successful migrants of littoral species from Iberian shores towards Madeira during glacial periods is expected, taking advantage on the smaller distances and favourable currents and winds. During Pleistocene glacial-interglacial cycles, short-duration events have occurred during which, short-lived oceanic currents must have been established, especially during or shortly after glacial terminations. During these short-term events, the arrival of species to the Azores due to range expansion processes may have been increased and facilitated by temporary sea surface currents that no longer exist today. With favourable sea-surface currents and winds, both planktotrophic and non-planktotrophic species (these via rafts) successfully arrived to the Azores and the fossil record of Santa Maria Island testifies this. Acknowledgements. – The authors thank Mr. Pombo (Vila do Porto) for useful information about the fossils and outcrops of Santa Maria Island. Thanks are also due to Emilio Rolán, Serge Gofas, Marien Faber, Jeroen THE BIOGEOGRAPHY OF THE MARINE MOLLUSCS OF THE AZORES Goud, Jacobus van Aartsen, Anselmo Peñas, Constantine Mifsud, Marco Oliverio, Henk Dijkstra, Giancarlo Paganelli and António Monteiro for helping on the identification of some species. The Clube Naval de Santa Maria is acknowledged for providing sea transportation to survey the shorelines of Santa Maria Island. We would like to thank the organization of the “Workshop Fósseis de Santa Maria”, that was held at Vila do Porto (21 to 27 of June 2002) and all the students that helped in the collecting during this period, as well as Direcção Regional da Ciência e Tecnologia (Açores), Direcção Regional do Ambiente (Açores), Direcção Regional da Juventude (Açores) and Câmara Municipal de Vila do Porto, for financial support. 305 The first author also thanks Miguel Matias for helping in the collecting of samples in February 2003 at Lagoinhas. Jorge Medeiros (CIRN/Universidade dos Açores) is acknowledged for the SEM photos. We also thank António Moniz (Secção de Geografia, Universidade dos Açores) for the maps of the Azores and Santa Maria Island. S.P. Ávila was supported by grant SFRH/BPD/22913/2005 (FCT – Fundação para a Ciência e Tecnologia) of the Portuguese government. Research at IMAR-DOP/UAc (UI&D #531 and ISR LA#9) is funded by FCT/MCTES– Lisbon and DRCT/Azores through pluri-annual and programmatic funding schemes (part FEDER). References AGOSTINHO J. (1937). – Sobre a tectónica da ilha de Santa Maria. – Açoreana, 1, 281-286. ALVES M.L.G.R. & SIMÕES A. (1997). – Azores Current system modelling and monitoring. Operational oceanography. The challenge for European co-operation. In : J. H. STEL, H. W. A. BEHRENS, J. C. BORST, J. L. DROPPERT and J. P. VAN DER MEULEN, Eds, Proc. First Internat. Conf. on EuroGOOS 7-11, October 1996, The Hague, The Netherlands, 62, 428-435. ALVES M.L.G.R. & DE VERDIÈRE A. C. (1999). – Instability dynamics of a subtropical jet and applications to the Azores Front Current System : eddy-driven mean flow. – J. Phys. Oceanogr., 29, 837-864. ALVES M., GAILLARD F., SPARROW M., KNOLL M. & GIRAUD S. (2002). – Circulation patterns and transport of the Azores Front-Current system. – Deep-Sea Research, 49, 3893-4002. ÁVILA S.P. (2000a). – Shallow-water marine molluscs of the Azores : biogeographical relationships. – Arquipélago, Life and Marine Sciences, Supplement 2 (Part A), 99-131. ÁVILA S.P. (2000b). – The shallow-water Rissoidae (Mollusca, Gastropoda) of the Azores and some aspects of their ecology. – Iberus, 18 (2), 51-76. ÁVILA S.P. (2003). – The littoral molluscs (Gastropoda, Bivalvia and Polyplacophora) of São Vicente, Capelas (São Miguel Island, Azores): ecology and biological associations to algae. – Iberus, 21 (1), 11-33. ÁVILA S.P. (2005). – Processos e padrões de dispersão e colonização nos Rissoidae (Mollusca: Gastropoda) dos Açores. – PhD Thesis, Universidade dos Açores, Ponta Delgada, 349 pp. ÁVILA S.P. (2006). – Oceanic islands, rafting, geographical range and bathymetry: a neglected relationship? In: T.J. HAYDEN, D.A. MURRAY A ND J.P.O ’CONNOR , Eds, Proc. 5 th internat. Symp. on the fauna and flora of Atlantic Islands, Dublin, 24-27 August 2004. – Occasional Publ. Irish Biogeogr. Soc., 9, 22-39. ÁVILA S.P. & ALBERGARIA A. (2002). – The shallow-water Polyplacophora of the Azores and some comments on the biogeographical relationships of the Azorean malacofauna. – Boll. Malacologico, 38(1-4), 41-44. ÁVILA S.P. & MALAQUIAS M.A. (2003). – Biogeographical relationships of the molluscan fauna of the Ormonde seamount (Gorringe bank, Northeast-Atlantic Ocean). – J. Molluscan Studies, 69, 145-150. ÁVILA S.P., AZEVEDO J.M.N., GONÇALVES J.M., FONTES J. & CARDIGOS F. (1998). – Checklist of the shallow-water marine molluscs of the Azores: 1 – Pico, Faial, Flores and Corvo islands. – Açoreana, 8(4), 487-523. ÁVILA S.P., AZEVEDO J.M.N., GONÇALVES J.M., FONTES J. & CARDIGOS F. (2000a). – Checklist of the shallow-water marine molluscs of the Azores: 2 – São Miguel island. – Açoreana, 9(2), 139-173. ÁVILA S.P., FONTES J., TEMPERA F. & CARDIGOS F. (2000b). – Additions to the marine molluscs of the Formigas islets, Azores. – Açoreana, 9(2), 175-178. ÁVILA S.P., AMEN R., AZEVEDO J.M.N., CACHÃO M. & GARCÍA-TALAVERA F. (2002). – Checklist of the Pleistocene marine molluscs of Prainha and Lagoinhas (Santa Maria Island, Azores). – Açoreana, 9(4), 343-370. ÁVILA S.P., SANTOS A.C., PENTEADO A.M., RODRIGUES A.M., QUINTINO I. & MACHADO M.I. (2005). – The molluscs of the intertidal algal turf in the Azores. – Iberus, 23(1), 67-76. ÁVILA S.P., MADEIRA P., MENDES N., REBELO A., MEDEIROS A., GOMES C., G ARCÍA -T ALAVERA F., M ARQUES DA S ILVA C., C ACHÃO M., H ILLAIRE -M ARCEL C. & DE F RIAS M ARTINS A.M. (2008a). – Mass extinctions in the Azores during the last glaciation : fact or myth? – J. Biogeogr., 35, 1123-1129. doi: 10.1111/ j.1365-2699.2008.01881. ÁVILA S.P., MADEIRA P., MARQUES DA SILVA C., CACHÃO M., LANDAU B., QUARTAU R. & DE FRIAS MARTINS A.M. (2008b). – Local disappearance of bivalves in the Azores during the last glaciation. – J. Quatern. Sci., 23, 777-785. doi.wiley.com/10.1002/jqs.1165. BERTHOIS L. (1950). – Sur la présence d’une microfaune dans le calcaire de Santa Maria (Açores). – Açoreana, 4(4), 277-287. BERTHOIS L. (1951). – Sur la présence de basses terrasses marines dans l’Archipel des Açores. – C. R. 76éme Congrès des Sociétés Savantes à Rennes, 101-106. BERTHOIS L. (1953). – Contribution à l’étude lithologique de l’Archipel des Açores. – Comunicações dos Serviços Geológicos de Portugal, 34, 1-198, 13 pls. BEU A.G. (2001). – Gradual Miocene to Pleistocene uplift of the Central American isthmus: evidence from tropical American tonnoidean gastropods. – J. Pal., 75(3), 706-720. BOEHLERT G.W., WILSON C.D. & MIZUNO K. (1994). – Populations of the sternoptychid fish Maurolicus muelleri on seamounts in the Central North Pacific. – Pacific Science, 48, 57-69. BOUCHET P. & TAVIANI M. (1992). – The Mediterranean deep-sea fauna : pseudopopulations of Atlantic species? – Deep-sea Research, 39, 169-184. BROECKER W.S. & HENDERSON G.M. (1998). – The sequence of events surrounding Termination II and their implications for the cause of glacial-interglacial CO2 changes. – Paleoceanography, 13, 352-364. CALLAPEZ P. & SOARES A.F. (2000). – Late Quaternary marine mollusks from Santa Maria (Azores); paleoecologic and paleobiogeographic considerations. – Ciências da Terra (UNL), 14, 313-322. CHESTER R. & JOHNSON L. R. (1971). – Atmospheric dusts collected off the Atlantic coasts of North Africa and the Iberian peninsula. – Mar. Geol., 11, 251– 260. CLARK P.U. & MIX A.C. (2002). – Ice sheets and sea level of the Last Glacial Maximum. – Quatern. Sci. Rev., 21(1-3), 1-7. COATES A.G. & OBANDO J.A. (1996). – The geological evolution of the Central American isthmus. In: J. B. C. JACKSON, A. F. BUDD and A. G. COATES, Eds, Evolution and environment in tropical America, 21-56. – University of Chicago Press, Chicago. COTTER J.C.B. (1888-1892). – Notícia de alguns fósseis terciários da ilha de Santa Maria no Archipélago dos Açores. – Comunicações da Comissão de Trabalhos Geológicos de Portugal, 2, 255-287. CROWLEY T.J. (1981). – Temperature and circulation changes in the eastern North Atlantic during the last 150,000 years : evidence from the planktonic foraminiferal record. – Mar. Micropal., 6, 97-129. CROWLEY T.J. & NORTH G.R. (1991). – Paleoclimatology. – Oxford University Press, New York, 339 p. Bull. Soc. géol. Fr., 2009, no 4 306 ÁVILA S. P. et al. F ERREIRA O.V. (1952). – Os pectinídeos do Miocénico da ilha de Santa Maria (Açores). – Revista da Faculdade de Ciências de Lisboa, 2ª Série, C, 2(2), 243-258. FERREIRA O.V. (1955). – A fauna Miocénica da ilha de Santa Maria. – Comunicações dos Serviços Geológicos de Portugal, 36, 9-44. FRAZIER J., MARGARITOULIS D., MULDOON K., POTTER C.W., ROSEWATER J., RUCKESCHEL C. & SALES S. (1985). – Epizoan communities on marine turtles. 1. Bivalves and gastropod Mollusca. – Marine Ecology Progress Series, 6, 127-140. FRIEDLANDER I. (1929). – Die Azoren. – Zeitschrift für Vulkanologie, 12, 77-107. GARCÍA-TALAVERA F. (1981). – Los moluscos gasteropodos anfiatlanticos (estudio paleo y biogeografico de las especies bentonicas litorales). – Universidad de la Laguna, secretariado Publicaciones, Coleccion Monografias, 10, 1-352 + VI laminas. GARCÍA-TALAVERA F. (1990). – Fauna tropical en el Neotirreniense de Santa Maria (I. Azores). – Lavori S.I.M., 23, 439-443. GARCÍA-TALAVERA F. (1999). – La Macaronesia. Consideraciones geológicas, biogeográficas y paleoecológicas. In : J. M. FERNÁNDEZ-PALACIOS , J. J. B ACALLADO and J. A. B ELMONTE , Eds, Ecología y cultura en Canarias. – Museo de las Ciencas y el Cosmos, 41-63. GARCÍA-TALAVERA F., KARDAS S.J. & RICHARDS H.G. (1978). – Quaternary marine mollusks from Tenerife, Canary Islands. – The Nautilus, 92(3), 97-102. GERBER J., HEMMEN J. & GROH K. (1989). – Eine pleistozäne marine Molluskenfauna von Porto Santo (Madeira-Archipel). – Mitt. Deutsch. Malakozool. Ges., 44-45, 19-30. GITTENBERGER E., GROENENBERG D.S.J., KOKSHOORN B. & PREECE R.C. (2006). – Molecular trails from hitch-hiking snails. – Nature, 439, 409. GONÇALVES J.M., THORPE J.P. & NASH R.D.M. (2000). – Allozyme variation in Octopus vulgaris in Northeast Atlantic : preliminary results. – CIAC 2000 Symposium Cephalopod Biomass and Production, University of Aberdeen, Scotland, U.K., 5-7 July 2000. GOULD W.J. (1985). – Physical oceanography on the Azores front. – Progress in Oceanography, 14(1-4), 167-190. HAUG G.H. & TIEDEMANN R. (1998). – Effect of the formation of the Isthmus of Panama on Atlantic Ocean thermohaline circulation. – Nature, 393, 673-676. HIGHSMITH R.C. (1985). – Floating and larval rafting as potential dispersal mechanisms in brooding invertebrates. – Marine Ecology Progress Series, 25, 169-179. JABLONSKI D. & LUTZ R.A. (1980). – Molluscan larval shell morphology : ecological and paleontological applications. In : D. C. RHOADS and R. A LUTZ, Eds, Skeletal growth of aquatic organisms. – Plenum, New York, 323-377. JABLONSKI D. & LUTZ R.A. (1983). – Larval ecology of marine invertebrates : paleobiological implications. – Biol. Rev., 58, 21-89. JOKIEL P.L. (1984). – Long-distance dispersal of reef corals by rafting. – Coral Reefs, 3, 69-76. JOKIEL P.L. (1990). – Long-distance dispersal by rafting : reemergence of an old hypothesis. – Endeavour, New Series, 14, 66-73. KÄSE R.H. & SIEDLER G. (1982). – Meandering of the subtropical front south-east of the Azores. – Nature, 300, 245-246. KLEINE B. & SIEDLER G. (1989). – On the origin of the Azores current. – J. Geophys. Res., 94(C5), 6159-6168. KREJCI-GRAF K., FRECHEN J., WETZEL W. & COLOM G. (1958). – Gesteine und Fossilien von den Azoren. – Senckenberg. Lethaea, 39, 303-351. LAMBECK K. & CHAPPELL J. (2001). – Sea-level change through the last glacial cycle. – Science, 292, 679-686. LANDAU B., MARQUES DA SILVA C. & VERMEIJ G. (2009). – Pacific elements in the Caribbean Neogene gastropod fauna: the source-sink model, larval development, disappearance, and faunal units. – Bull. Soc. géol. Fr., 180, 4, 343-352. LAURSEN D. (1981). – Taxonomy and distribution of teleplanic prosobranch larvae in the North Atlantic. – Dana-Report, 89, 1-43. MAC ANDREW R. (1854). – On the geographical distribution of testaceous Mollusca in the North Atlantic and neighbouring seas. – H. Greenwood, Liverpool, 51 p. MADEIRA J.E.O. (1986). – Geologia estrutural e enquadramento geotectónico da ilha de Santa Maria (Açores). – MSc. Thesis, Lisboa, 107 p. Bull. Soc. géol. Fr., 2009, no 4 MALAQUIAS M.A.E. (2001). – Updated and annotated checklist of the opisthobranch molluscs (excluding Thecosomata and Gymnosomata) from the Azores archipelago (North Atlantic Ocean, Portugal). – Iberus, 19, 37-48. MAYER K. (1864). – Die Tertiär-Fauna der Azoren und Madeiren. Systematisches Verzeichniss der fossilen Reste von Madeira, Porto Santo und Santa Maria nebst Beschreibung der neuen Arten, VI+107pp. Zürich. MCINTYRE A., KIPP N.G., BÉ A.W.H., CROWLEY T., KELLOGG T., GARDNER J.V., PRELL W. & RUDDIMAN W.F. (1976). – Glacial North Atlantic 18,000 years ago : a CLIMAP reconstruction. – Mem. Geol. Soc. Amer., 145, 43-76. MORTON B. & BRITTON J.C. (2000). – The origins of the coastal and marine flora and fauna of the Azores. – Oceanogr. Mar. Biol. : an Annual Review, 38, 13-84. MORTON B., BRITTON J.C. & DE FRIAS MARTINS A.M. (1998). – Ecologia Costeira dos Açores. – Sociedade Afonso Chaves, Ponta Delgada. X+249pp. Ó FOIGHIL D. (1989). – Planktotrophic larval development is associated with a restricted geographic range in Lasaea, a genus of brooding, hermaphroditic bivalves. – Mar. Biol., 103, 349-358. Ó FOIGHIL D., JENNINGS R., PARK J.-K. & MERRIWETHER A. (2001). – Phylogenetic relationships of mid-oceanic ridge and continental lineages of Lasaea spp. (Mollusca : Bivalvia) in the northeastern Atlantic. – Mar. Ecology Progress Series, 213, 165-175. PETIT R.H., LEGRAND M., JANKOWIAK I., MOLINIE J., DE BEAUVILLE C.A., MARION G. & MANSOT J.L. (2005). – Transport of Saharan dust over the Caribbean islands: study of an event. – J. Geophys. Res.-Atmospheres, 110 (D18), Art. No. D18S09. RAFFI S. (1986). – The significance of marine boreal mollusks in the early Pleistocene faunas of the Mediterranean area. – Palaeogeogr., Palaeoclimatol., Palaeoecol., 52, 267-289. REIS M.A, OLIVEIRA O.R., ALVES L.C., RITA E.M.C., RODRIGUES F., FIALHO P., PIO C.A. & FREITAS M.C. (2002). – Comparison of continental Portugal and Azores Islands aerosol during a Sahara dust storm. – Nuclear Instruments and Methods in Physics Research Section B-Beam interactions with materials and atoms, 189, 272-278. SCHELTEMA R.S. (1971). – The dispersal of larvae of shoal-water benthic invertebrate species over long distances by ocean currents. In : D.J. CRISP, Ed., Fourth Marine Biology Symposium, Cambridge. – Cambridge University Press, Cambridge, 7-28. SCHELTEMA R.S. (1977). – Dispersal of marine invertebrate organisms : paleobiogeographic and biostratigraphic implications. In : R.G. KAUFFMANN et J.E. HAZEL, Eds, Concepts and methods of biostratigraphy, 73-108. – Dowden, Hutchinson and Ross, Stroudsburg, Pennsylvania, Xiii+ 658 p. SCHELTEMA R.S. (1986a). – Long distance dispersal by planktonic larvae of shoal-water benthic invertebrates among central Pacific Islands. – Bull. Mar. Sci., 39, 241-256. SCHELTEMA R.S. (1986b). – On dispersal and planktonic larvae of benthic invertebrates : an eclectic overview and summary of problems. – Bull. Mar. Sci., 39, 290-322. SCHELTEMA R.S. (1989). – Planktonic and non-planktonic development among prosobranch gastropods and its relationship to the geographic range of species. In : J.S. RYLAND and P.A. TYLER, Eds, Reproduction, genetics and distribution of marine organisms. – Olsen and Olsen, International Symposium Series, 183-188. SCHIEBEL R., SCHMUKER B., ALVES M. & HEMLEBEN C. (2002). – Tracking the Recent and late Pleistocene Azores front by the distribution of planktic foraminifers. – J. Mar. Systems, 37, 213-227. SERRALHEIRO A. (2003). – A geologia da ilha de Santa Maria, Açores. – Açoreana, 10, 141-192. SERRALHEIRO A. & MADEIRA J. (1990). – Stratigraphy and geochronology of Santa Maria island (Azores). – Livro de Homenagem ao Prof. Carlos Romariz. Departamento de Geologia da Faculdade de Ciências da Universidade de Lisboa, 357-376. SERRALHEIRO A., ALVES C.M., FORJAZ V.H. & RODRIGUES B. (1987). – Carta vulcanológica dos Açores, Ilha de Santa Maria. – Centro de Vulcanologia INIC, Ponta Delgada. STRATHMANN R.R. (1974). – The spread of sibling larvae of sedentary marine invertebrates. – Am. Naturalist, 108, 29-44. THE BIOGEOGRAPHY OF THE MARINE MOLLUSCS OF THE AZORES WAELBROECK C., LABEYRIE L., MICHEL E., DUPLESSY J.C., MC MANNUS J.F., LAMBECK K., BALBON E. & LABRACHERIE M. (2002). – Sea-level and deep water temperature changes derived from benthic foraminifera isotopic records. – Quat. Sci. Rev., 21, 295-305. WILSON G.S. et al. (2000). – Chronostratigraphy of the CRP-2/2A drillcore, Ross Sea, Antarctica. – Museo Nazionale dell’Antartide – Siena – Italie. WIRTZ P., OCAÑA O. & MOLODTSOVA T. ( 2003). – Actiniaria and Ceriantharia of the Azores (Cnidaria Anthozoa). – Helgoland Mar. Res., 57, 114-117. WUNSCH C. (2003). – Determining paleoceanographic circulations, with emphasis on the Last Glacial Maximum. – Quat. Sci. Rev., 22, 371-385. 307 YOLOHAMA Y., LAMBECK K., DE DECKER P., JOHNSTON P. & FIEFIELD K. (2000). – Timing of the last glacial Maximum from observed sea level minima. – Nature, 406, 713-716. ZBYSZEWSKY G. & DA V. FERREIRA O. (1961). – La faune marine des basses plages quaternaires de Praia et Prainha dans l’ile de Santa Maria (Açores). – Comunicações dos Serviços Geológicos de Portugal, 45, 467-478. ZBYSZEWSKY G. & DA V. FERREIRA O. (1962). – Étude géologique de l’île de Santa Maria (Açores). – Comunicações dos Serviços Geológicos de Portugal, 46, 209-245. ZBYSZEWSKY G., DA V. FERREIRA O. & DE ASSUNÇÃO C.T. (1961). – Carta Geológica de Portugal na escala 1/50 000. Notícia explicativa da folha de Ilha de Santa Maria (Açores). – Serviços Geológicos de Portugal, Lisboa, 28 p. Bull. Soc. géol. Fr., 2009, no 4
Documentos relacionados
Onl_Er_jbi_1881 1..7 - MPB - Marine PalaeoBiogeography
standard U/Th methodology at the GEOTOP laboratory (Université du Québec à Montreal, Canada). Results Dating of the shells of P. aspera indicates that the deposition of the lower unit of the Pra...
Leia maisobservations of fin whales (balaenoptera physalus) around the
D. João de Castro Bank (DJC) is a shallow seamount with hydrothermal activity located between the islands of Terceira and São Miguel, Azores (Portugal). Due to its remote location, few investigator...
Leia maisThe biodiversity of terrestrial arthropods in Azores
-042 Angra do Heroísmo, Açores, Portugal. cE3c – Centre for Ecology, Evolution and Environmental Changes / Azorean Biodiversity Group and Universidade dos Açores - Departamento de Ciências Agrárias...
Leia maisCONTEÚDO 3 1st Atlantic Islands Neogene, International Congress
Departamento de Biologia, Universidade dos Açores, 9501-801 Ponta Delgada, São Miguel, Açores, Portugal; 2 MPB, Marine PalaeoBiogeography Working Group of the University of Azores, Departamento de ...
Leia mais