TL;DR: The phylogenetic position of the ancient family Pleurotomariidae within the Molluscan class Gastropoda, as well as the relationships of its Recent genera and species, were assessed using an iterative, two-gene approach to phylogeny reconstruction.
Abstract: The phylogenetic position of the ancient family Pleurotomariidae within the Molluscan class Gastropoda, as well as the relationships of its Recent genera and species, were assessed using an iterative, two-gene (18S rDNA and cytochrome c oxidase I) approach to phylogeny reconstruction. In order to orient the Pleurotomariidae within Gastropoda, partial 18S rDNA sequences were determined for 7 pleurotomariid and 22 other gastropods that span the major groups within the class as well as for one cephalopod and two polyplacophorans, which serve as outgroups. Cladistic analyses of a sequence of approximately 450 base pairs (bp) near the 5' end of the 18S rDNA support the monophyly of the following higher gastropod taxa: Patellogastropoda, Vetigastropoda, Neritopsina, Apogastropoda, and its subclades Caenogastropoda and Heterobranchia. The 18S rDNA sequences and 579 bp of cytochrome c oxidase I (COI) analyzed separately and together, indicate that Pleurotomariidae are included within Vetigastropoda but comprise a clade that is the sister group to the other families referred to this order. Monophyly of the Pleurotomariidae is also supported by the unique presence of seven separate inserts (ranging in length from 1 to 68 bp) within the V2 variable region of the 18S RNA. Relationships of the genera and species within Pleurotomariidae are fully resolved using "total molecular evidence" consisting of partial sequences of 18S rDNA and COI and including data on length variation within the inserts.
TL;DR: A cladistic analysis of the shell microstructures of Recent Vetigastropoda demonstrates it is more parsimonious to assume crossed lamellar shell structures, rather than nacreous, are plesiomorphic, and it is suggested, that Phasianellidae is neither part of nor sister taxon to Turbinidae.
Abstract: A cladistic analysis of the shell microstructures of Recent Vetigastropoda demonstrates, it is more parsimonious to assume crossed lamellar shell structures, rather than nacreous, are plesiomorphic. The clade Vetigastropoda is characterized by having intersected crossed platy shell structure. The analysis suggests resolution of the internal phylogeny of the Vetigastropoda, particularly separation of a crown group with nacreous shells, composed of Haliotidae, Pleurotomariidae, Seguenziidae, Stomatellidae, Trochidae, and Turbinidae, separated from an unresolved grade with cross lamellar structures, Fissurellidae, Osteopeltidae, and Pseudococculinidae. It is also suggested, that Phasianellidae is neither part of nor sister taxon to Turbinidae.
TL;DR: The assemblage shows a strong Tethyan affinity at generic level, but has a distinctly endemic species content, and thus merits a distinct subprovince within the Indo-Madagascan Faunal Province.
Abstract: Mesozoic gastropod assemblages currently emerged from Kutch, western India constitute one of the most diverse communities known during the Bathonian–Oxfordian worldwide. The present paper describes part of the Jurassic gastropod faunas of the family Pleurotomariidae from Kutch, comprising ten species belonging to three genera, of which eight species are new. They are: Bathrotomaria reticulata (Sowerby), B. waageni sp. nov., B. calloviana sp. nov., B. buddhai sp. nov., B. prasantai sp. nov., B. dhosaensis sp. nov., B. tewarii (Maithani); Leptomaria daityai sp. nov.; L. asurai sp. nov. and Obornella wuerttembergensis (Sieberer). The assemblage shows a strong Tethyan affinity at generic level, but has a distinctly endemic species content, and thus merits a distinct subprovince within the Indo-Madagascan Faunal Province. The genus Pleurotomaria is discussed in historical perspective and shown to be Mesozoic genus. The six species of Bathrotomaria described herein are considered to have evolved from t...
TL;DR: The Danian molluscan fauna from the Paris Basin presents a chronological interest of first importance for the understanding of the diversification of European marine ecosystems at the beginning of the Cenozoic.
Abstract: The Danian molluscan fauna from the Paris Basin presents a chronological interest of first importance for the understanding of the diversification of European marine ecosystems at the beginning of the Cenozoic. The method consisting in the study of all external prints of molluscs from silicone rubber casts reveals an unexpected faunal diversity. The systematics of 23 species of Patellogastropoda and Vetigastropoda (pro parte) from the Danian perireefal limestone of Vigny (Val-d'Oise, France) and other Danian localities of the Paris Basin are presented here. This study will be completed by further papers in which the Danian molluscan fauna will be revised. Ten new species are described and included in the families Acmaeidae (Scurria dysporista n. sp., Scurriopsis deretrana n. sp.), Fissurellidae (Emarginula (s.s.) horrida n. sp., E. (s.s.) minacis n. sp., E. (s.s.) eucosmia n. sp., E. (s.s.) cavernosa n. sp., Entomella necopinata n. sp., Hemitoma (Montfortia) davincii n. sp., Clypidina (Montfortula) celinae n. sp.) and Pleurotomariidae (Leptomaria meyeri n. sp.). Nine species are reported for the first time from the Danian of Paris Basin (Acmaea simplex, Patella vincenti, Proscutum montense n. comb., Emarginula (s.s.) coralliora, E. (s.s.) montensis, Diodora corneti, D. dolloi, D. concentrica, Praescissurella corneti). Emarginula cretacea d'Orbigny, 1850 is considered a nomen dubium. A new species from the Thanetian of Bioues (Haute-Garonne, France), Emarginula (s.s.) villattae n. sp., is introduced and Emarginula (s.s.) jagti n. nom. is proposed as a replacement name for Emarginula radiata Binkhorst, 1861 non Adams, 1851.
TL;DR: The presence of these Triassic pleurotomariids with nearshore brachiopod and molluscan taxa, within fine‐ to coarse‐grained sandstone, suggests they lived in shallow shelf environments, in contrast to the outer shelf to upper bathyal distribution of modern pleuro tomariids.
Abstract: Pleurotomariid gastropods occur as background faunal elements in commonly richly fossiliferous assemblages in New Zealand and New Caledonian Triassic rocks. Most forms are represented by few individual specimens, making description and characterisation difficult. This work on the New Zealand and New Caledonian Triassic pleurotomariids has led to the recognition of 12 new species distributed between the genera Talantodiscus (1 new species; ?Talantodiscus mackayi n. sp.), Pleurotomaria (5 new species; P. karetai n. sp., P. waimumu n. sp., P. otapiriensis n. sp., P. kiritehereensis n. sp., and P. awakinoensis n. sp.), and the three new genera, Murihikua (3 new species; M. tuhawaiki n. sp., M. marwicki n. sp., and M. aparima n. sp.), Mamoea (1 new species; M. wairakiensis n. sp.), and Tahua (2 new species; T. waipiro n. sp., and T. taiaroa n. sp.). The previously described Talantodiscus trechmanni (Marwick), and Pleurotomaria hectori (Trechmann) are also reviewed. Pleurotomariid gastropods are found ...