Micromolluscs (76 gastropods, 10 bivalves) and 27 juvenile specimens of larger species. (0-45 m water depth) in Matai Bay, Northland, New Zealand. Species of marine molluscs (96 gastropods, 21 bivalves) are recorded from 16 dredge stations
Seventy-five species of benthic marine ostracods, 120 species of benthic foraminifera and 113 is proposed for the oldest New Zealand species of crassatellid, ‘Eucrassatella’ australis. Two species (‘Spissatella’ subobesa and the Australian ‘S.’ maudensis) are transferred to the genus Eucrassatella the genus Spissatella is redescribed and the species assigned to it are reviewed.
#Snails and squids belong to the phylum full#
A full revision of the New Zealand species of Spissatella and Eucrassatella is presented, incorporating the results of this new phylogenetic analysis. kingicola (Lamarck), form a derived group that is sister to Spissatella. According to the resulting phylogeny, New Zealand taxa currently included in the genus Eucrassatella do not form a monophyletic group: ‘Eucrassatella’ australis (Hutton) occupies a basal position with regards to the rest of the taxa, and the remaining species of Eucrassatella, including the Australian type species E. We use stratocladistic methods combined with morphometric data to produceĪ phylogeny of two closely related genera of New Zealand crassatellid bivalves-Spissatella Finlay, 1926 and Eucrassatella Iredale, 1924-and find that the inclusion of the stratigraphic character improves congruence of tree to data, as measured Thus while deep-water seeps in New Zealand were repeatedly or continuously colonized by members of the global seep fauna, the general mollusk fauna of the New Zealand region developed a considerable degree of endemism during this time.Īccurate, phylogenetically informed taxonomy is required for any group of organisms to be used in biostratigraphy, palaeoecologicalĪnd palaeoenvironmental studies, or palaeoclimatology. In contrast to the general marine mollusk fauna of New Zealand, which shows a high degree of endemism in both the Cenozoic and Recent, New Zealand's Cretaceous to present-day seep faunas consist largely of taxa known from coeval seeps around the world.
The carbonates preserve a typical mollusk dominated, Late Mesozoic, deep-water seep fauna including the large modiomorphid bivalve Caspiconcha, the lucinid bivalve Ezolucina, and limpets, hokkaidoconchids and a large abyssochrysoid among the gastropods, with close biogeographic relationships to North Pacific seep faunas of Cretaceous age. V-PDB) and biphytane (−99‰), and the bacterial biomarker anteiso-C 15 fatty acid (−47‰), reveal that sulfate-dependent anaerobic oxidation of methane (AOM) induced the formation of these deposits. V-PDB) and 13 C-depleted molecular fossils such as the archaeal biomarkers pentamethylicosane (−97‰ vs. These petrographic features, in combination with negative δ 13 C values of early diagenetic micrites (as low as −29.2‰ vs. The dominant petrographic fabric of the carbonates is detrital micrite, and the numerous fenestrae and vugs are filled with various cements including two types of non-detrital micrite, and botryoidal and banded fibrous calcites.
Dinoflagellate dating indicates a Late Albian to mid-Cenomanian age for three deposits from Port Awanui, and a mid-Campanian age for two deposits from Waipiro Bay and for one from Owhena Stream. Six Cretaceous methane-seep deposits are reported from the Raukumara Peninsula, eastern North Island, New Zealand.