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The recent discovery and exploration of deep-sea hydrothermal vent fields in the Mid-Cayman Spreading Centre, Caribbean Sea (Beebe Vent Field, 4956–4972 m depth) and the East Scotia Ridge, Southern Ocean (E2 and E9 vent fields, 2394–2641 m depth) have yielded extensive collections of two new provannid species, Provanna beebei n. sp. and P. cooki n. sp. Morphological and molecular taxonomy (530 bp of the mitochondrial cytochrome c oxidase subunit I gene) confirm P. beebei n. sp. and P. cooki n. sp. as distinct species; these species are formally described, and details are provided of their distribution, habitat and species associations. Bayesian and maximum likelihood analyses support the placement of P. beebei n. sp. and P. cooki n. sp within the genus Provanna and show that these two new deep-sea species form a well-supported clade with the abyssal West Pacific P. cingulata. Provanna beebei n. sp. and P. cooki n. sp. represent the first records of Provanna from hydrothermal vents in the Caribbean Sea and Southern Ocean, respectively, and extend the known geographic range of the genus. For the first time, intraspecific phenotypic variation in size and sculpture has been reported for Provanna. At the East Scotia Ridge, shell-size frequency distributions and median shell size of P. cooki n. sp. varied significantly between the E2 and E9 vent fields, as well as between diffuse flow and high-temperature venting habitats within each field. The variation in shell sculpture in relation to habitat was also observed in P. cooki n. sp.

BackgroundGastropods of the genusProvannaare abundant and widely distributed in deep-sea chemosynthetic environments with seven extant species described in the northwestern Pacific.MethodsWe investigated the population history and connectivity of fiveProvannaspecies in the northwestern Pacific through population genetic analyses using partial sequences of the cytochromecoxidase subunit I gene.ResultsWe found thatP. subglabra, the most abundant and genetically diverse species, is genetically segregated by depth. Among the five species, the three comparatively shallower species (P. lucida, P. kuroshimensis, P. glabra) had a more constant demographic history compared to the deeper species (P. subglabra,P. clathrata).DiscussionEnvironmental differences, especially depth, appears to have a role in the segregation ofProvannasnails. The population ofP. clathratain the Irabu Knoll appears to have expanded afterP. subglabrapopulation. The remaining three species,P. lucida,P. kuroshimensis, andP. glabra, are only known from a single site each, all of which were shallower than 1,000 m. These data indicate thatProvannagastropods are vertically segregated, and that their population characteristics likely depend on hydrothermal activities.

Sixteen gastropod species from two Campanian (Upper Cretaceous) hydrocarbon seep localities in Hokkaido, Japan are described. Seven species are new: the acmaeid limpet Serradonta omagariensis; three turbinids: Homalopoma abeshinaiensis, Cantrainea yasukawensis, and C. omagariensis; the trochid Margarites sasakii; the seguenzioid Cataegis nakagawensis; and the provannid Provanna nakagawensis. The most common species in the investigated localities are acmaeid limpets (S. omagariensis), tiny turbinids (H. abeshinaiensis, C. yasukawensis, C. omagariensis), and provannids/hokkaidoconchids (P. nakagawensis and Hokkaidoconcha hikidai). The Upper Cretaceous associations described here do not resemble Lower Cretaceous associations known from other regions but are composed of species similar to gastropods from Recent hydrocarbon seeps and hydrothermal vents in the Northwestern Pacific. This strongly suggest that this region possesses a regional pool of gastropods in chemosynthesis-based communities at least since L...

A fauna of provannid and provannid-like shells is described from Upper Cretaceous seep carbonates in Hokkaido, Japan. We describe two new provannid species, Provanna tappuensis sp. nov. and Desbruyeresia kanajirisawensis sp. nov., with preserved protoconchs of unquestionable provannid type with decollate apex. This material confirms the occurrence of Provannidae as early as the Middle Cenomanian. We also describe Hokkaidoconcha gen. nov. and a new family Hokkaidoconchidae fam. nov., with two named species, H. hikidai sp. nov. and H. tanabei sp. nov. Hokkaidoconchidae are possibly related to the Provannidae, judging from a similar, but not decollate larval shell, although the juvenile teleoconch whorls differ in being of a general cerithimorph appearance and the details of the aperture are unknown. Furthermore, we review the published fossil record of Provannidae and Abyssochrysidae, and we consider that in those older than the Eocene, there is no evidence preserved that unequivocally supports a position there. The Jurassic Acanthostrophia acanthica from Italy seems to be the oldest known record of Abyssochrysidae, and the most reliable occurrence of the family, older than from the Miocene. Other fossil, pre-Miocene species that have been classified in the Abyssochryssidae are provisionally referred to Hokkaidoconchidae. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154, 421–436.

Eighteen gastropod and seven bivalve species are reported from Eocene to Oligocene cold-seep carbonates in Washington State, USA. Four species are new (Niso littlei, Turrinosyrinx hickmanae, Xanthodaphne? campbellae, and Lurifax goederti), and 16 are described in open nomenclature. Previously unknown features of protoconch or prodissoconch morphology and/or shell microstructure are provided for Retiskenea statura (Goedert and Benham), Provanna antiqua Squires, Nuculana? aff. N. grasslei Allen, and Bathy- modiolus willapaensis (Squires and Goedert). Modiolus (M.) willapaensis is placed within Bathymodiolus based on the elliptical- triangular shape of its juvenile shell, indicating that the divergence between vent/seep and whale/wood-fall inhabiting bathymodiolines took place at least 40 Ma. The first fossil species of the vent/seep genera Pyropelta (Pyropeltidae), Lurifax (family uncertain), and Catillopecten? (Propeamussidae) are reported. Niso (Eulimidae), Xanthodaphne, Turrinosyrinx, Benthomangelia (Turridae), Ledella (Nuculanidae), Tindaria? (Tindariidae), and Delectopecten (Pectinidae) are reported for the first time from fossil cold-seep assemblages. Larval developmental strategies are inferred from protoconch and prodissoconch morphologies in 14 species, which largely reflect the species' phylogenetic groups, as in modern vent and seep molluscs. The data presented here indicate that the radiation of toxoglossate turrids (Gastropoda) into deep water took place already in the Oligocene, and not in the Miocene as previously thought. Healed shell injuries and presumed naticid drill holes represent the oldest known fossil evidence of predation at cold-seeps.

The genomic DNA of two Provanna sp. individuals was extracted, sequenced using an Illumina HiSeq1500, and the mitogenome was assembled. The nearly complete metogenome was 16,183 bp in length, consisting of 37 typical metazoan mitochondrial genes with the typical caenogastropod mitochondrial gene order. All mitochondrial genes were encoded on the heavy strand with the exception of eight transfer RNA genes. To reconstruct the phylogenetic position of the deep-sea Provannidae, we used amino acid sequences of all the 13 mitochondrial protein-coding genes in Bayesian inference, maximum likelihood, and maximum parsimony analyses with sequences of selected gastropods. The resultant phylogenetic trees supported the placement of Provannidae in the superfamily Abyssochrysoidea of the clade Littorinimorpha of Gastropoda, providing new data for understanding the phylogeny of these deep-sea snails.

A limited fauna of relatively simple, thin-walled, hexactinellid sponges, including moderately coarse-textured, funnellike Hexactinella(?) conica new species, fine-textured, tubular to branched Hexactinella(?) tubula new species, fragments of delicate Eurete goederti(?) Rigby and Jenkins, 1983, and Farrea(?) species, has been found in the Oligocene Lincoln Creek Formation on Canyon River, in the southcentral part of the Olympic Peninsula, Washington. These sponges dominate a chemosynthetic invertebrate assemblage that included the gastropod Provanna antigua Squires, 1995; the polyplacophoran Leptochiton alveolus (Lovén, 1846), and radiolarians. Most of the sponges are preserved as silica in a localized cherty and botryoidal, calcareous cement-filled limestone formed at bathyal depths by bacterial oxidation of methane at a cold seep. This is the third known report of sponges from ancient chemosynthetic deposits.

Provanna marshalli sp. nov. is described from Early to Middle Miocene-age fossil hydrocarbon seep localities in the East Coast Basin, North Island, New Zealand, adding to 18 modern and three fossil species of the genus described. Modern species are well represented at hydrothermal vent sites as well as at hydrocarbon seeps and on other organic substrates in the deep-sea, including sunken wood and whale falls. All described fossil Provanna species are restricted to hydrocarbon seep deposits, with a few reports of suspected fossil specimens of the genus from other chemosynthetic environments such as plesiosaurid carcasses, and the oldest occurrences are dated to the Middle Cenomanian (early Late Cretaceous). The New Zealand fossil species is the most variable species of the genus described to date, and may be conspecific with, or antecedent to, a poorly sampled, undescribed modern species found at seep sites off the East Coast of North Island. The microstructure of a fossil Provanna species is reported here for the first time, and found to be comparable to some modern specimens of the genus.