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Phorcus gallicophorcus Landau, Van Dingenen & Ceulemans, 2017 † Late Miocene (Tortonian): NE Atlantic (France: Loire Basin). (Landau et al. 2017)

Subgenus Phorcus Risso, 1826 Type species. Phorcus margaritaceus Risso, 1826 [= Phorcus richardi (Payraudeau, 1826)], SD (Bucquoy et al. 1885: 399). Present-day, Mediterranean Sea. Diagnosis. Subtriangular, turbiniform shells with moderately convex teleoconch whorls and convex base. Umbilicus initially open, narrowing during ontogeny; usually minute or fully sealed, but open in few species. Shell surface either smooth or with low, broad spiral cords (see also Affenzeller et al. 2017). Remarks. The oldest occurrences are documented from the Late Miocene of the NE Atlantic (Landau et al. 2017; Martín-González et al. 2018). Mediterranean records all post-date the Messinian Salinity Crisis, suggesting an immigration with Atlantic faunas during the early Pliocene. The generic placement of extant species follows Donald et al. (2012). = Neptheusa Leach in Gray, 1852; type species: Trochus crassus Pulteney, 1799, by monotypy. Present-day, British Isles. = Umbiculus Nordsieck, 1982; type species Trochus richardi var. pallida Bucquoy, Dautzenberg & Dollfus, 1884 [= Phorcus richardi (Payraudeau, 1826)], OD (Nordsieck 1982: 26). Present-day, Mediterranean Sea. Introduced as “Sektion” (= section) of Gibbula (Gibbula), which makes it an available name according to ICZN Article 10.4. (A uninominal name proposed for a genus-group division of a genus, even if proposed for a secondary (or further) subdivision, is deemed to be a subgeneric name even if the division is denoted by a term such as “section” or “division). = Mutilastra Nordsieck, 1974; type species Trochus mutabilis Philippi, 1851, OD (Nordsieck 1974: 21). Present-day: NE Atlantic (Portugal); Mediterranean Sea., Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on page 50, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/4419088, {"references":["Affenzeller, S., Haar, N. & Steiner, G. (2017) Revision of the genus complex Gibbula: an integrative approach to delineating the Eastern Mediterranean genera Gibbula Risso, 1826, Steromphala Gray, 1847, and Phorcus Risso, 1826 using DNA-barcoding and geometric morphometrics (Vetigastropoda, Trochoidea). Organisms Diversity & Evolution, 17 (4), 789 - 812. https: // doi. org / 10.1007 / s 13127 - 017 - 0343 - 5","Landau, B. M., van Dingenen, F. & Ceulemans, L. (2017) The upper Miocene gastropods of northwestern France, 1. Patellogastropoda and Vetigastropoda. Cainozoic Research, 17 (2), 75 - 166.","Martin-Gonzalez, E., Vera-Pelaez, J. L., Castillo, C. & Lozano-Francisco, M. C. (2018) New fossil gastropod species (Mollusca: Gastropoda) from the upper Miocene of the Canary Islands (Spain). Zootaxa, 4422 (2), 191 - 218. https: // doi. org / 10.11646 / zootaxa. 4422.2.3","Donald, K. M., Preston, J., Williams, S. T., Reid, D. R., Winter, D., Alvarez, R., Buge, B., Hawkins, S. J., Templado, J. & Spencer, H. G. (2012) Phylogenetic relationships elucidate colonization patterns in the intertidal grazers Osilinus Philippi, 1847 and Phorcus Risso, 1826 (Gastropoda: Trochidae) in the northeastern Atlantic Ocean and Mediterranean Sea. Molecular Phylogenetics and Evolution, 62 (1), 35 - 45. https: // doi. org / 10.1016 / j. ympev. 2011.09.002","Bucquoy, E., Dautzenberg, P. & Dollfus, G. (1884, 1885) Les mollusques marins du Roussillon. Tome Ier. Gastropodes. Bailliere & fils, Paris, pp. 197 - 342 (1884), pp. 343 - 418 (1885). [http: // www. biodiversitylibrary. org / item / 103592]"]}

Phorcus atratus (Wood, 1828) Present-day: E Atlantic (Canary Islands, Madeira). Canaries and Madeira only, other records are misidentifications. The Cape Verde populations are distinguished as P. mariae (Templado & Rolán 2012). (MolluscaBase 2020l), Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on page 50, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/4419088

Phorcus lineatus (da Costa, 1778) = Trochus crassus Pulteney, 1799 Pleistocene: NE Atlantic (France). Present-day: NE Atlantic (British Isles, Portugal, Spain, Mauritania). (Glibert 1962), Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on pages 50-51, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/4419088, {"references":["Da Costa, E. M. (1778) Historia naturalis testaceorum Britanniae, or, the British conchology; containing the descriptions and other particulars of natural history of the shells of Great Britain and Ireland: illustrated with figures. In English and French. - Historia naturalis testaceorum Britanniae, ou, la conchologie Britannique; contenant les descriptions & autres particularites d'histoire naturelle des coquilles de la Grande Bretagne & de l'Irlande: avec figures en taille douce. En anglois & Francois. Millan, White, Emsley & Robson, London, 254 pp. [https: // www. biodiversitylibrary. org / page / 13116783]","Glibert, M. (1962) Les Archaeogastropoda fossiles du Cenozoique etranger des collections de l'Institut royal des Sciences naturelles de Belgique. Memoires de l'Institut Royal des Sciences Naturelles de Belgique, 68, 3 - 131. [http: // biblio. naturalsciences. be / rbins-publications / memoirs-of-the-royal-institute-of-natural-sciences-of-belgium-second-series / 68 - 1962]"]}

Phorcus gallicophorcus Landau, Van Dingenen & Ceulemans, 2017 † Late Miocene (Tortonian): NE Atlantic (France: Loire Basin). (Landau et al. 2017), Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on page 50, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/4419088, {"references":["Landau, B. M., van Dingenen, F. & Ceulemans, L. (2017) The upper Miocene gastropods of northwestern France, 1. Patellogastropoda and Vetigastropoda. Cainozoic Research, 17 (2), 75 - 166."]}

Phorcus (Osilinus) sauciatus (Koch in Philippi, 1845) Present-day: NE Atlantic (Bay of Biscay, Portugal, Canary Islands, Morocco, Madeira). (Rubal et al. 2014), Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on page 52, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/4419088

Phorcus burgadoi Martín-González in Martín-González, Vera-Peláez, Castillo & Lozano-Francisco, 2018 † Late Miocene (Tortonian): NE Atlantic (Canary Islands). (Martín-González et al. 2018), Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on page 50, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/4419088, {"references":["Martin-Gonzalez, E., Vera-Pelaez, J. L., Castillo, C. & Lozano-Francisco, M. C. (2018) New fossil gastropod species (Mollusca: Gastropoda) from the upper Miocene of the Canary Islands (Spain). Zootaxa, 4422 (2), 191 - 218. https: // doi. org / 10.11646 / zootaxa. 4422.2.3"]}

Phorcus mariae Templado & Rolán, 2012 Present-day: NE Atlantic (Cape Verdes). (Templado & Rolán 2012)

* Phorcus (Osilinus) turbinatus (Born, 1778) Pliocene (Zanclean): Mediterranean Sea (Spain: Estepona Basin; Italy). Pliocene (Piacenzian): Mediterranean Sea (Italy). Pleistocene (Gelasian to late Pleistocene): Mediterranean Sea (France; Balearic Islands; Italy; Cyprus). Present-day: Mediterranean Sea. (Landau et al. 2003), Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on page 52, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/4419088, {"references":["Born, I. (1778) Index rerum naturalium Musei Caesarei Vindobonensis. Pars I. ma. Testacea. Verzeichniss der nat ʾ rlichen Seltenheiten des k. k. Naturalien Cabinets zu Wien. Erster Theil. Schalthiere. Kraus, Vindobonae, XL + 458 pp. [https: // www. biodiversitylibrary. org / item / 43890 page / 7 / mode / 1 up] https: // doi. org / 10.5962 / bhl. title. 11581"]}

* Phorcus richardi (Payraudeau, 1826) Figs 7M 1 –M 2 Pliocene (Zanclean): Mediterranean Sea (Spain: Estepona Basin, Italy). Pliocene (Piacenzian): Mediterranean Sea (Italy). Pleistocene: Mediterranean Sea (Italy), NE Atlantic (Morocco). Present-day: Mediterranean Sea. (Landau et al. 2003; Chirli 2004), Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on page 51, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/4419088, {"references":["Chirli, C. (2004) Archaeogastropoda. Malacofauna Pliocenica Toscana, 4, 1 - 113."]}

Phorcus mariae Templado & Rolán, 2012 Present-day: NE Atlantic (Cape Verdes). (Templado & Rolán 2012), Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on page 51, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/4419088

Phorcus punctulatus (Lamarck, 1822) Pleistocene (late Pleistocene): E Atlantic (Morocco). Present-day: E Atlantic (Senegal, Gambia). (Glibert 1962), Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on page 51, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/4419088, {"references":["Lamarck, J. P. B. A. de Monet de (1822) Histoire naturelle des animaux sans vertebres ... precedee d'une introduction offrant la determination des caracteres essentiels de l'animal, sa distinction du vegetal et des autres corps naturels, enfin, l'exposition des principes fondamentaux de la zoologie. Lamarck, Paris, 711 pp. [https: // www. biodiversitylibrary. org / item / 47433 page / 9 / mode / 1 up]","Glibert, M. (1962) Les Archaeogastropoda fossiles du Cenozoique etranger des collections de l'Institut royal des Sciences naturelles de Belgique. Memoires de l'Institut Royal des Sciences Naturelles de Belgique, 68, 3 - 131. [http: // biblio. naturalsciences. be / rbins-publications / memoirs-of-the-royal-institute-of-natural-sciences-of-belgium-second-series / 68 - 1962]"]}

Genus Phorcus Risso, 1826 Type species. Phorcus margaritaceus Risso, 1826, Published as part of Mart��n-Gonz��lez, Esther, Vera-Pel��ez, Jos�� Luis, Castillo, Carolina & Lozano-Francisco, M. Carmen, 2018, New fossil gastropod species (Mollusca: Gastropoda) from the upper Miocene of the Canary Islands (Spain), pp. 191-218 in Zootaxa 4422 (2) on page 203, DOI: 10.11646/zootaxa.4422.2.3, http://zenodo.org/record/1251497, {"references":["Risso, A. (1826) Histoire naturelle des principales productions de l'Europe Meridionale et particulierement de celles des environs de Nice et des Alpes Maritimes 4. IV. F. G. Levrault, Paris, 439 pp."]}

Phorcus burgadoi Mart��n-Gonz��lez sp. nov. Figure 7 A, B, C Type material. Holotype: complete, well-preserved shell of a large adult specimen (H: 35.6 mm; W: 34.8 mm), record number TFMCFO-6109. Paratypes: six specimens with record numbers TFMCFO-4623 (H: 15.6 mm; W: 16.6 mm); TFMCFO-6109a (H: 24.9 mm; W: 23 mm); TFMCFO-6109b (H: 24.7 mm; W: 23.9 mm); TFMCFO- 6109c (H: 35.6 mm; W: 27.9 mm); TFMCFO-3726 (H: 31.8 mm; W: 30.3 mm); TFMCFO-3780 (H: 30.5 mm; W: 28.2 mm). Other material examined. Overall, 45 specimens, two from Lanzarote (TFMCFO-1835, Barranco de las Pilas), and 43 from Fuerteventura (TFMCFO-3420, Morrete de los Castrillos; TFMCFO-3443, Acantilados de Aldiana; TFMCFO-3462, TFMCFO-3707, TFMCFO-4623, TFMCFO-6109, TFMCFO-6406, Bajas Amarillas; TFMCFO-3465, TFMCFO-6407, TFMCFO-6541, Playa del ��guila; TFMCFO-3726, Punta del Viento; TFMCFO- 3743, Majada Blanca; TFMCFO-3752, Barranco de Esquinzo; TFMCFO-4158, Gran Valle; TFMCFO-3780, TFMCFO-6533, TFMCFO-6583, TFMCFO-6584, Aljibe de la Cueva). Table 5 contains the descriptive biometrics and statistics for the species. Type locality. Bajas Amarillas (Fuerteventura, Canary Islands). UTM 28 R 593643 m E 3161892 m N, 10 m asl. The level is composed of poorly cemented, dark gray biogenic sandstones. Dated as Tortonian by the gastropod association described above. The paratypes are from the same type locality, as well as from Punta del Viento and Aljibe de la Cueva, in Fuerteventura. Etymology. The specific epithet refers to the common name given in the Canary Islands to the species in this genus, burgado. Description. Shell large for the genus (Hmax: 35.6 mm; Wmax: 34.8 mm), robust, trochiform, of equal height and width, with an elevated conical spire. Protoconch paucispiral, slightly eroded. Teleoconch consists of five convex whorls with a straight, linear and superficial suture, and a very prominent ramp. Superficial sculpture lacking in the adult individuals, except for the fine prosocline and opisthocyrt growth lines. In juvenile shells, very attenuated, longitudinal cords on the penultimate whorl. Suture line on last whorl is slightly convex at its end. Base evenly rounded, non-umbilicate. Aperture holostomatous with rounded, unthickened labrum. Short thin callus ending in a single blunt tooth at the columellar edge. Color not preserved; the holotype is black, probably due to taphonomic disturbances. Remarks. Phorcus burgadoi sp. nov. has not been described in previous works on the Canarian Neogene, despite its considerable size. The genus Phorcus is represented in the Canary Islands by two species, P. sauciatus (Koch in Philippi, 1845) and P. atratus (Wood, 1828), which are clearly different from the new taxon because of their smaller size and general shape. Phorcus burgadoi sp. nov. has a higher spire and a more rounded last whorl than P. sauciatus and P. atratus has a stepped shape with straighter and less globular whorls. Phorcus burgadoi sp. nov. presents some characteristics very similar to those of P. lineatus (da Costa, 1778). They differ in the aperture, which is slightly more closed in P. lineatus, also presenting a slight point in the collumelar tooth of adult specimens, and P. burgadoi sp. nov. has a higher spire. Phorcus turbinatus (Born, 1778) differs from Phorcus burgadoi sp. nov. by having a higher conical spire and a subquadrangular. The same features distinguish the new species from P. articulatus (Lamarck, 1822). Phorcus articulatus also differs in having an ornament of spiral cords separated by fine flutings. Phorcus (Trochocochlea) miocaenica (Mayer, 1858) from the French Atlantic Miocene differs from Phorcus burgadoi sp. nov. by having an ornament of spiral cords. Distribution. Upper Miocene, Tortonian: Fuerteventura, Lanzarote and Gran Canaria., Published as part of Mart��n-Gonz��lez, Esther, Vera-Pel��ez, Jos�� Luis, Castillo, Carolina & Lozano-Francisco, M. Carmen, 2018, New fossil gastropod species (Mollusca: Gastropoda) from the upper Miocene of the Canary Islands (Spain), pp. 191-218 in Zootaxa 4422 (2) on pages 203-205, DOI: 10.11646/zootaxa.4422.2.3, http://zenodo.org/record/1251497, {"references":["Philippi R. A. (1845) Bemerkungen uber die Molluskenfauna von Massachusetts. Zeitschrift fur Malakozoologie, 2, 68 - 79","Wood, W. (1828) Supplement to the Index Testaceologicus; or a catalogue of shells, British and Foreign. Illustrated with 480 figures. Richard Taylor for W. Wood, London, vi + 59 pp., 8 pls.","Da Costa, E. M. (1778) Historia Naturalis Testaceorum Britanniae, or, the British Conchology. Millan, White, Elmsley & Robson, London, xii + 254 + viii pp., 17 pls.","Born, I. von (1778) Index rerum naturalium Musei Caesarei Vindobonensis. Pars I. ma. Testacea. Erster Theil. Verzeichniss der naturlichen Seltenheiten des k. k. Naturalien Cabinets zu Wien. Schalthiere, 458 pp.","Lamarck J. B. M. (1822) Histoire naturelle des animaux sans vertebres. Tome Septieme. Paris, 711 pp.","Mayer, C. (1858) Description de coquilles nouvelles des etages superieurs des terrains tertiaires. Journal du Conchologie, 7, 73 - 89."]}

Phorcus burgadoi Martín-González sp. nov. Figure 7 A, B, C Type material. Holotype: complete, well-preserved shell of a large adult specimen (H: 35.6 mm; W: 34.8 mm), record number TFMCFO-6109. Paratypes: six specimens with record numbers TFMCFO-4623 (H: 15.6 mm; W: 16.6 mm); TFMCFO-6109a (H: 24.9 mm; W: 23 mm); TFMCFO-6109b (H: 24.7 mm; W: 23.9 mm); TFMCFO- 6109c (H: 35.6 mm; W: 27.9 mm); TFMCFO-3726 (H: 31.8 mm; W: 30.3 mm); TFMCFO-3780 (H: 30.5 mm; W: 28.2 mm). Other material examined. Overall, 45 specimens, two from Lanzarote (TFMCFO-1835, Barranco de las Pilas), and 43 from Fuerteventura (TFMCFO-3420, Morrete de los Castrillos; TFMCFO-3443, Acantilados de Aldiana; TFMCFO-3462, TFMCFO-3707, TFMCFO-4623, TFMCFO-6109, TFMCFO-6406, Bajas Amarillas; TFMCFO-3465, TFMCFO-6407, TFMCFO-6541, Playa del Águila; TFMCFO-3726, Punta del Viento; TFMCFO- 3743, Majada Blanca; TFMCFO-3752, Barranco de Esquinzo; TFMCFO-4158, Gran Valle; TFMCFO-3780, TFMCFO-6533, TFMCFO-6583, TFMCFO-6584, Aljibe de la Cueva). Table 5 contains the descriptive biometrics and statistics for the species. Type locality. Bajas Amarillas (Fuerteventura, Canary Islands). UTM 28 R 593643 m E 3161892 m N, 10 m asl. The level is composed of poorly cemented, dark gray biogenic sandstones. Dated as Tortonian by the gastropod association described above. The paratypes are from the same type locality, as well as from Punta del Viento and Aljibe de la Cueva, in Fuerteventura. Etymology. The specific epithet refers to the common name given in the Canary Islands to the species in this genus, burgado. Description. Shell large for the genus (Hmax: 35.6 mm; Wmax: 34.8 mm), robust, trochiform, of equal height and width, with an elevated conical spire. Protoconch paucispiral, slightly eroded. Teleoconch consists of five convex whorls with a straight, linear and superficial suture, and a very prominent ramp. Superficial sculpture lacking in the adult individuals, except for the fine prosocline and opisthocyrt growth lines. In juvenile shells, very attenuated, longitudinal cords on the penultimate whorl. Suture line on last whorl is slightly convex at its end. Base evenly rounded, non-umbilicate. Aperture holostomatous with rounded, unthickened labrum. Short thin callus ending in a single blunt tooth at the columellar edge. Color not preserved; the holotype is black, probably due to taphonomic disturbances. Remarks. Phorcus burgadoi sp. nov. has not been described in previous works on the Canarian Neogene, despite its considerable size. The genus Phorcus is represented in the Canary Islands by two species, P. sauciatus (Koch in Philippi, 1845) and P. atratus (Wood, 1828), which are clearly different from the new taxon because of their smaller size and general shape. Phorcus burgadoi sp. nov. has a higher spire and a more rounded last whorl than P. sauciatus and P. atratus has a stepped shape with straighter and less globular whorls. Phorcus burgadoi sp. nov. presents some characteristics very similar to those of P. lineatus (da Costa, 1778). They differ in the aperture, which is slightly more closed in P. lineatus, also presenting a slight point in the collumelar tooth of adult specimens, and P. burgadoi sp. nov. has a higher spire. Phorcus turbinatus (Born, 1778) differs from Phorcus burgadoi sp. nov. by having a higher conical spire and a subquadrangular. The same features distinguish the new species from P. articulatus (Lamarck, 1822). Phorcus articulatus also differs in having an ornament of spiral cords separated by fine flutings. Phorcus (Trochocochlea) miocaenica (Mayer, 1858) from the French Atlantic Miocene differs from Phorcus burgadoi sp. nov. by having an ornament of spiral cords. Distribution. Upper Miocene, Tortonian: Fuerteventura, Lanzarote and Gran Canaria.

The oxygen isotope composition (δ18O) recorded in shells of the gastropods Patella candei crenata and Phorcus atratus from the Canary Islands (27–29°N) potentially provide invaluable high-resolution paleoclimatic data. However, because these two species have never been studied isotopically, it is necessary to calibrate and validate this approach by using live-collected specimens that can be compared to present-day climate data. For P. candei crenata, live organisms were collected at 15-day intervals for nearly one year (between 2011 and 2012) from the rocky-intertidal coast of SE Tenerife along with sea surface temperatures (SST) and seawater δ18O values. The δ18O values of the last growth episode along the shell growth margin, representing the conditions when organisms were collected, illustrate that P. candei crenata δ18O values were 1.3 ± 0.2‰ higher than expected values from isotopic equilibrium. This finding resulted in estimated SST 5.7 ± 0.6 °C lower than observed values. This offset or “vital effect” is uniform and predictable, and therefore can be corrected by subtracting 1.3‰ from the measured shell δ18O value. Adjusted temperatures from the shell coincided with observed SST in the study area. Therefore, Patella candei crenata shells are reliable repositories of SST data, in agreement with other species of Patella from higher latitudes. For Phorcus atratus, a live specimen was analyzed isotopically along shell-growth direction. The intrashell δ18O values showed the entire range of measured SST in the region without an apparent “vital effect”, in correspondence with other Phorcus species from the Mediterranean. Both Patella candei crenata and Phorcus atratus are common components of archaeological and Pleistocene-Holocene paleontological sites across the Canary Archipelago. This study suggests that well-preserved shells of these two taxa retrieved from ancient settings have the capacity to serve as excellent high-resolution paleotemperature archives for the tropical/subtropical eastern Atlantic region.

Snails in the closely related trochid genera Phorcus Risso, 1826 and Osilinus Philippi, 1847 are ecologically important algal grazers in the intertidal zone of the northeastern Atlantic Ocean and Mediterranean Sea. Here we present the first complete molecular phylogeny for these genera, based on the nuclear 28S rRNA gene and the mitochondrial 16S rRNA and COI genes, and show that the current classification is erroneous. We recognize nine species in a single genus, Phorcus: estimated by BEAST analysis, this arose 30 (±10) Ma; it consists of two subgenera, Phorcus and Osilinus, which we estimate diverged 14 (±4.5) Ma. Osilinus kotschyi, from the Arabian and Red Seas, is not closely related and is tentatively referred to Priotrochus Fischer, 1879. Our phylogeny allows us to address biogeographical questions concerning the origins of the Mediterranean and Macaronesian species of this group. The former appear to have evolved from Atlantic ancestors that invaded the Mediterranean on several occasions after the Zanclean Flood, which ended the Messinian Salinity Crisis 5.3. Ma; whereas the latter arose from several colonizations of mainland Atlantic ancestors within the last 3 (±1.5) Ma. © 2011 Elsevier Inc., R.A. and J.T. were funded by the Spanish Ministerio de Educación y Ciencia (Project CGL2007-60954).