Rafael La Perna

PLEISTOCENE BATHYAL MOLLUSCAN ASSEMBLAGES FROM SOUTHERN ITALY

Four Pleistocene bathyal molluscan assemblages from southern Italy (Calabria and Messina area) were studied. One hundred and thirty-six species were recorded. Twenty-four were classified and described in detail and thirty-five were illustrated. The following new combinations are pro posed: Solariella marginulata (Philippi, 1844), Iphitus tenuisculptus (Seguenza, 1876), Benthomangelia tenuicostata (Seguenza, 1879), Chrysallida microscalaria (Seguenza, 1876), Ennucula corbuloides (Seguenza, 1877), Ennucula rotundata (Seguenza, 1877), Thestyleda cuspidata (Philippi, 1844), Katadesmia confusa (Seguenza, 1877), Austrotindaria pusio (Philippi, 1844), Austrotindaria salicensis (Seguenza, 1877). Comments concerning the taxonomy of Fissurisepta Seguenza, 1862, Solariella Wood, 1842, Ennucula Iredale, 1931, Thestyleda Iredale, 1929, Ledella Verrill & Bush, 1897, Yoldiella Verrill & Bush, 1897, Bathyspinula Filatova, 1958, Katadesmia Dall, 1908, Austrotindaria Fleming, 1948 and Cadulus Philippi, 1844 are included. The assemblages are dominated by nuculoids and fit the general compositional pattern of the deep-sea molluscan communities. A paleodepth of 500-600 m is inferred for two assemblages, whereas a greater depth, pro bably not exceeding 1,000 m, is suggested for the other two. Taxonomic affinities with northeast Atlantic and more generally with World Ocean deep-sea molluscan faunas are remarkable. The Plio-Quaternary evolution of the deep Mediterranean benthos is discussed.

The identity of Yoldia micrometrica Seguenza, 1877 and three new deep-sea protobranchs from the Mediterranean (Bivalvia)

Three new species are described from the relatively well-known deep Mediterranean protobranch fauna. Yoldiella wareni n. sp. is a miniaturized species so far misidentified as Yoldiella micrometrica (Seguenza, 1877), which is a Pleistocene species (neotype here designated). Yoldiella ovulum n. sp. is similar to Y. micrometrica, of which it may represent a descendant species. Ledella marisnostri n. sp. is the second species known for the genus in the Mediterranean. These three species are thought to be endemic to the Mediterranean, where they may represent either persisting Plio-Pleistocene species which survived the changes from psychrospheric to homeothermic conditions, or newly adapted species, evolved from Plio-Pleistocene ancestors. In the second case, they seem to be the result of an ongoing differentiation of the deep Mediterranean protobranch fauna from the North-East Atlantic one, due to the physical isolation of the Mediterranean basin.Three new species are described from the relatively well-known deep Mediterranean protobranch fauna. Yoldiella wareni n. sp. is a miniaturized species so far misidentified as Yoldiella micrometrica (Seguenza, 1877), which is a Pleistocene species (neotype here designated). Yoldiella ovulum n. sp. is similar to Y. micrometrica, of which it may represent a descendant species. Ledella marisnostri n. sp. is the second species known for the genus in the Mediterranean. These three species are thought to be endemic to the Mediterranean, where they may represent either persisting Plio-Pleistocene species which survived the changes from psychrospheric to homeothermic conditions, or newly adapted species, evolved from Plio-Pleistocene ancestors. In the second case, they seem to be the result of an ongoing differentiation of the deep Mediterranean protobranch fauna from the North-East Atlantic one, due to the physical isolation of the Mediterranean basin.

Biogeography of Iberian Atlantic Neogene Marginelliform Gastropods (Marginellidae, Cystiscidae): Global Change and Transatlantic Colonization

Abstract The Marginellidae Fleming and the Cystiscidae Stimpson, herein collectively referred to as marginelliform gastropods, are convergent families of thermophilic marine gastropods. Shallow-water marginelliform gastropods are found in the Ibero-Moroccan Gulf and Mediterranean, diversity rapidly increasing towards tropical West Africa. Surprisingly, in the tropical and subtropical European Miocene fossil record, marginelliform genera of tropical affinity such as Persicula Schumacher and Prunum Herrmannsen, occurring today in West Africa, are altogether missing. Others, such as Marginella Lamarck, are present only in the southwestern Iberian and Mediterranean Neogene record. This work describes the marginelliform gastropods from the Atlantic Iberian Neogene. Ten species are recorded, of which three are new, Persicula mikhailovae n. sp., Gibberula costae n. sp., and Gibberula brebioni n. sp. This study shows that Gibberula Swainson and Volvarina Hinds have been present in Europe since the Eocene. Marginella may have originated in southern Africa and migrated north to Europe in the Miocene, never extending further north than west central Portugal. Persicula and Prunum probably originated in the Caribbean and migrated east during the Pliocene, following closure of the Central American Seaway. The colonization of the Pliocene European Atlantic coast by gastropods of these genera was selective, only where high sea-water temperature and high productivity were combined. These findings suggest that post-Messinian recolonization of the Mediterranean during the Pliocene was a complex process, involving colonization by groups originating in various regions of the Atlantic, including Europe, Africa and the Americas.

Homalopoma emulum (Seguenza, 1876)a bathyal cold stenothermic gastropod in the Mediterranean PleistoceneHomalopoma emulum (Seguenza, 1876) un gastéropode bathyal sténothermefroid dans le Pléistocène méditerranéen

Abstract Homalopoma emulum Seguenza , 1876) is a poorly known gastropod from the bathyal deposits of the Mediterranean Lower Pleistocene (Strait of Messina area). Its affinity with Homalopoma globuloides ( Dautzenberg & Fischer , 1896 ) living on the bathyal bottoms of the Northeast Atlantic Ocean (Azores and Gulf of Biscay) is very high and the two species are more closely related than two simply congeneric species. Homalopoma emulum belongs to a category of Mediterranean Plio-Pleistocene deep-water species characterized by remarkable taxonomic, morphologic and ecologic affinities with deep-water species from the Atlantic Ocean, or extra-Mediterranean areas in general. Such affinities seem to indicate a cold-stenothermic character, incompatible with the present deep homothermy in the Mediterranean Sea. The reason for the extinction of these species is referred to homothermic episodes which took place cyclically during the interglacial phases of the Upper Pleistocene. A progressive and selective extinction of these species led to the present lack of cold-stenothermic species in the Mediterranean deep benthos.

A revision of the genus Europicardium Popov, 1977 (Bivalvia: Cardiidae) from the European Neogene: tracking palaeogeography and climate changes

The cardiid genus Europicardium Popov, 1977 was introduced for a small group of Cenozoic species from Europe, but remained almost unknown in the western literature until about 15 years ago, and its type species, Cardium multicostatum Brocchi, 1814, continued to be cited mainly as Trachycardium multicostatum. Many records are available for this species from the Miocene of Europe, but most are based on several distinct, often misidentified species. In the present revision, based on museum material, the taxonomy of Europicardium is discussed and the identity of its type species is fixed. Seven species are assigned to Europicardium: E. multicostatum (Brocchi, 1814), E. miorotundatum (Sacco, 1899) (lectotype designated), E. miocaudatum (Sacco, 1899), E. polycolpatum (Cossmann & Peyrot, 1912), E. pseudomulticostatum (Zhizhchenko, 1934), E. badeniense (Kókay, 1996) and E. hoernesi sp. nov. from the middle Miocene of Austria. However, literature records and museum material suggest the occurrence of additional species and the need for further investigation. The oldest record of Europicardium is from the early Miocene of the Aquitaine Basin, from where the genus likely spread into the Mediterranean and throughout the Paratethys. Europicardium reached a maximum diversity in the early middle Miocene (Badenian) of the Paratethys, probably in relation to the Miocene Climatic Optimum, and also with the complex and variable palaeogeography of the Paratethys, which promoted differentiation and diversity. Europicardium disappeared from the Paratethys when it became a freshwater basin in the late Miocene, and from the Mediterranean due to the Messinian Salinity Crisis. The last European species was E. multicostatum, which arrived in the Mediterranean from the adjacent Atlantic with the post-Messinian recolonization, and became extinct in the Pleistocene due to climatic deterioration. At the present day, Europicardium occurs in the tropical waters of West Africa, with three species. http://zoobank.org/urn:lsid:zoobank.org:pub:9074907D-410A-411E-8E51-EAAAF32209BD

Morphometric and systematic study on three Acanthocardia species from the Mediterranean Pleistocene (Mollusca, Bivalvia, Cardiidae)

ABSTRACT The cardiids Acanthocardia echinata (Linnaeus, 1758), A. deshayesii (Payraudeau, 1826) and A. lunulata (Seguenza, 1879) co-occur in the Mediterranean Pleistocene and are closely similar to each other, even partially overlapping in shell morphology. Of these, only A. echinata is fairly well known. Acanthocardia deshayesii has been considered a subspecies or even a synonym of A. echinata, whereas A. lunulata, only known from the original description, has been confused with A. deshayesii. The univariate and multivariate morphometric analysis on six shell characters substantiates the distinct taxonomic status of the three species. Acanthocardia mucronata (Poli, 1791), Cardium duregnei Monterosato, 1891 and C. bullatum Locard, 1892 are considered synonyms of A. echinata. Cardium propexum Monterosato, 1891 is proved to be a synonym of A. lunulata, an extinct species probably endemic to the Mediterranean, like A. deshayesii.

Systematic position of two Pliocene carditids with description of Akardita n. gen. and A. iberica n. sp. (Bivalvia: Carditidae)

Akardita n. gen. is described for a small Pliocene to Recent group of carditids. The type species is Cardita subrevoluta de Stefani, 1888, from the lower Pliocene of Italy. The new genus includes Akardita iberica n. sp., from the lower Pliocene of southern Spain, and Cardita (Venericardia) monodi Nicklès, 1953, an extant species from West Africa. A few additional Neogene species from Europe could turn out to be representatives of the new genus, whose disappearance from European seas seems to be related to an increasing cooling trend during the Neogene-Pleistocene interval. Because of the confused status of carditid taxonomy, about which some observations are reported in the present work, it is not possible to assign the new genus to any of the traditional subfamilies.

Bucardium grateloupianum n. sp. from the Lower Miocene of Aquitaine with taxonomic comments on some fossil species from Europe (Bivalvia, Cardiidae)

The genus Bucardium J. E. Gray, 1853 has been widely used in the past literature, either for living and fossil cardiids, but only a single species was known, its type species B. ringens (Bruguière, 1789), living in the tropical waters of West Africa. Another species, from the Lower Miocene of the Aquitaine Basin, turned out to be undescribed, though known since the 19th century. It is herein described as Bucardium grateloupianum n. sp. The genus seems to have always had a low diversity and a tropical distribution. Its disappearance in Europe coincides with the general cooling trend recorded after the Middle Miocene. Several poorly known cardiids from the Lower-Middle Miocene of France and Austria and from the Upper Oligocene of Hungary show closer morphological affinities with the living Cardium indicum Lamarck, 1819, rather than with the genus Bucardium or with Cardium costatum Linnaeus, 1758, the type species of Cardium Linnaeus, 1758. These affinities suggest the need of a systematic reappraisal of the living and fossil species currently assigned to Cardium.

On the Last Occurrence of Marginella Lamarck, 1799 (Gastropoda, Marginellidae) in the Mediterranean: Description of a New Species from the Early Pleistocene and Paleoceanographic Implications

ABSTRACT A new species of Marginella Lamarck, 1799 is described from the Early Pleistocene of the Messina Strait area, M. seguenzai n. sp. The remarkable variability in shell size and shape required a preliminary morphometric analysis, which provided evidence of a single species. This is the last known representative of the genus Marginella in the Mediterranean, today highly diverse in the tropical and subtropical shallow waters of West Africa, up to about 28°N. The genus Marginella was thought to have disappeared from the Mediterranean and the adjacent Atlantic after the Early Pliocene, due to early cooling phases. Anyway, Marginella seguenzai n. sp. was a deep water species, and its extinction was most probably due to the loss of psychrosphere, in the Early Pleistocene, rather than to climatic deterioration. The remarkable closeness between the new species and a deep water living species, endemic to three seamounts in the NE Atlantic, suggests a common origin for both species. High productivity seems to have been a key factor in the Mediterranean distribution of Marginella, either in shallow and deep waters.