The Indo-West Pacific venerid genus Lioconcha is reviewed, with special emphasis on species occur... more The Indo-West Pacific venerid genus Lioconcha is reviewed, with special emphasis on species occurring in the Australian and New Caledonian regions. Nineteen species, including four new species, are recognised: Lioconcha castrensis (Linnaeus, 1758), L. macaulayi n. sp., L. hieroglyphica (Conrad, 1837), L. tigrina (Lamarck, 1818), L. fastigiata (Sowerby, 1851), L. annettae Lamprell & Whitehead, 1990, L. pseudofastigiata n. sp., L. ornata (Dillwyn, 1817), L. berthaulti n. sp., L. sowerbyi (Deshayes, 1853), L. polita (Roding, 1798), L. schioettei n. sp., L. trimaculata (Lamarck, 1818), L. philippinarum (Hanley, 1844), L. dautzenbergi (Prashad, 1932), L. melharteae Lamprell & Stanisic, 1996, L. caledonensis Harte & Lamprell, 1999, L. richerdeforgesi Lamprell & Stanisic, 1996 and L. gordoni (E. A. Smith, 1885). Colour variation within species ranges from very high (L. ornata, L. castrensis) to very low (L. melharteae, L. caledonensis, L. philippinarum). All species are figured, diagnosed ...
Sperm ultrastructure is described for the ocean quahog Arctica islandica (Linnaeus, 1767) (Arctic... more Sperm ultrastructure is described for the ocean quahog Arctica islandica (Linnaeus, 1767) (Arcticidae), a long-lived, and commercially and phylogenetically important marine bivalve from the North Atlantic, and for Neotrapezium sublaevigatum (Lamarck, 1819), an Indo-Pacific member of the only other family of Arcticoidea (Trapezidae). Spermatozoa of A. islandica consist of (in anterior to posterior sequence): an elongate-conical, deeply invaginated, acrosomal vesicle (length 2.0 ± 0.2 μm; invagination occupied by a granular subacrosomal material); a straight, anteriorly-tapered, rod-shaped nucleus (length 6.6 ± 0.4 μm); a short (approximately 0.8 μm) midpiece consisting of two orthogonally arranged centrioles, surrounded by four (approximately 75% of spermatozoa observed) or, less commonly, five (approximately 25% of spermatozoa observed) spherical mitochondria; nine satellite fibres connecting the distal centriole to mitochondria and the plasma membrane; and a flagellum (length 60 ± ...
Molecular phylogenetics and evolution, Feb 10, 2016
The systematics of the molluscan class Bivalvia are explored using a 5-gene Sanger-based approach... more The systematics of the molluscan class Bivalvia are explored using a 5-gene Sanger-based approach including the largest taxon sampling to date, encompassing 219 ingroup species spanning 93 (or 82%) of the 113 currently accepted bivalve families. This study was designed to populate the bivalve Tree of Life at the family level and to place many genera into a clear phylogenetic context, but also pointing to several major clades where taxonomic work is sorely needed. Despite not recovering monophyly of Bivalvia or Protobranchia-as in most previous Sanger-based approaches to bivalve phylogeny-our study provides increased resolution in many higher-level clades, and supports the monophyly of Autobranchia, Pteriomorphia, Heteroconchia, Palaeoheterodonta, Heterodonta, Archiheterodonta, Euheterodonta, Anomalodesmata, Imparidentia, and Neoheterodontei, in addition to many other lower clades. However, deep nodes within some of these clades, especially Pteriomorphia and Imparidentia, could not b...
To re-evaluate the relationships of the major bivalve lineages, we amassed detailed morpho-anatom... more To re-evaluate the relationships of the major bivalve lineages, we amassed detailed morpho-anatomical, ultrastructural and molecular sequence data for a targeted selection of exemplar bivalves spanning the phylogenetic diversity of the class. We included molecular data for 103 bivalve species (up to five markers) and also analysed a subset of taxa with four additional nuclear protein-encoding genes. Novel as well as historically employed morphological characters were explored, and we systematically disassembled widely used descriptors such as gill and stomach ‘types’. Phylogenetic analyses, conducted using parsimony direct optimisation and probabilistic methods on static alignments (maximum likelihood and Bayesian inference) of the molecular data, both alone and in combination with morphological characters, offer a robust test of bivalve relationships. A calibrated phylogeny also provided insights into the tempo of bivalve evolution. Finally, an analysis of the informativeness of mo...
The Indo-West Pacific venerid genus Lioconcha is reviewed, with special emphasis on species occur... more The Indo-West Pacific venerid genus Lioconcha is reviewed, with special emphasis on species occurring in the Australian and New Caledonian regions. Nineteen species, including four new species, are recognised: Lioconcha castrensis (Linnaeus, 1758), L. macaulayi n. sp., L. hieroglyphica (Conrad, 1837), L. tigrina (Lamarck, 1818), L. fastigiata (Sowerby, 1851), L. annettae Lamprell & Whitehead, 1990, L. pseudofastigiata n. sp., L. ornata (Dillwyn, 1817), L. berthaulti n. sp., L. sowerbyi (Deshayes, 1853), L. polita (Roding, 1798), L. schioettei n. sp., L. trimaculata (Lamarck, 1818), L. philippinarum (Hanley, 1844), L. dautzenbergi (Prashad, 1932), L. melharteae Lamprell & Stanisic, 1996, L. caledonensis Harte & Lamprell, 1999, L. richerdeforgesi Lamprell & Stanisic, 1996 and L. gordoni (E. A. Smith, 1885). Colour variation within species ranges from very high (L. ornata, L. castrensis) to very low (L. melharteae, L. caledonensis, L. philippinarum). All species are figured, diagnosed ...
Sperm ultrastructure is described for the ocean quahog Arctica islandica (Linnaeus, 1767) (Arctic... more Sperm ultrastructure is described for the ocean quahog Arctica islandica (Linnaeus, 1767) (Arcticidae), a long-lived, and commercially and phylogenetically important marine bivalve from the North Atlantic, and for Neotrapezium sublaevigatum (Lamarck, 1819), an Indo-Pacific member of the only other family of Arcticoidea (Trapezidae). Spermatozoa of A. islandica consist of (in anterior to posterior sequence): an elongate-conical, deeply invaginated, acrosomal vesicle (length 2.0 ± 0.2 μm; invagination occupied by a granular subacrosomal material); a straight, anteriorly-tapered, rod-shaped nucleus (length 6.6 ± 0.4 μm); a short (approximately 0.8 μm) midpiece consisting of two orthogonally arranged centrioles, surrounded by four (approximately 75% of spermatozoa observed) or, less commonly, five (approximately 25% of spermatozoa observed) spherical mitochondria; nine satellite fibres connecting the distal centriole to mitochondria and the plasma membrane; and a flagellum (length 60 ± ...
Molecular phylogenetics and evolution, Feb 10, 2016
The systematics of the molluscan class Bivalvia are explored using a 5-gene Sanger-based approach... more The systematics of the molluscan class Bivalvia are explored using a 5-gene Sanger-based approach including the largest taxon sampling to date, encompassing 219 ingroup species spanning 93 (or 82%) of the 113 currently accepted bivalve families. This study was designed to populate the bivalve Tree of Life at the family level and to place many genera into a clear phylogenetic context, but also pointing to several major clades where taxonomic work is sorely needed. Despite not recovering monophyly of Bivalvia or Protobranchia-as in most previous Sanger-based approaches to bivalve phylogeny-our study provides increased resolution in many higher-level clades, and supports the monophyly of Autobranchia, Pteriomorphia, Heteroconchia, Palaeoheterodonta, Heterodonta, Archiheterodonta, Euheterodonta, Anomalodesmata, Imparidentia, and Neoheterodontei, in addition to many other lower clades. However, deep nodes within some of these clades, especially Pteriomorphia and Imparidentia, could not b...
To re-evaluate the relationships of the major bivalve lineages, we amassed detailed morpho-anatom... more To re-evaluate the relationships of the major bivalve lineages, we amassed detailed morpho-anatomical, ultrastructural and molecular sequence data for a targeted selection of exemplar bivalves spanning the phylogenetic diversity of the class. We included molecular data for 103 bivalve species (up to five markers) and also analysed a subset of taxa with four additional nuclear protein-encoding genes. Novel as well as historically employed morphological characters were explored, and we systematically disassembled widely used descriptors such as gill and stomach ‘types’. Phylogenetic analyses, conducted using parsimony direct optimisation and probabilistic methods on static alignments (maximum likelihood and Bayesian inference) of the molecular data, both alone and in combination with morphological characters, offer a robust test of bivalve relationships. A calibrated phylogeny also provided insights into the tempo of bivalve evolution. Finally, an analysis of the informativeness of mo...
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