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Baker AM Sheldon F Somerville J Walker KF Hughes JM 《Molecular phylogenetics and evolution》2004,32(3):902-912
In the Lake Eyre Basin, the Australian hyriid genus Velesunio is represented by three undescribed species, each of which are highly divergent genetically, but morphologically similar to Velesunio wilsonii (Lea 1859). A fourth species, Velesunio ambiguus (Philippi 1847), occurs not only in the Lake Eyre Basin but throughout much of eastern Australia, including the Murray-Darling Basin. In this study, we show that another hyriid, Alathyria jacksoni (Iredale 1934), which is sympatric with V. ambiguus, is genetically deeply nested within the Velesunio species complex, such that the genus Velesunio is paraphyletic with respect to A. jacksoni. Moreover, our mitochondrial phylogenetic reconstructions indicate that A. jacksoni is closely allied to one of the cryptic Velesunio species occurring in the Lake Eyre Basin, but distinct from V. ambiguus and the two other Velesunio species. These data suggest that the genera Alathyria and Velesunio are in need of revision. The shells of A. jacksoni and Velesunio spp. vary with local conditions and sometimes are difficult to distinguish. Our analyses also show that shell characters of these taxa do not closely match the phylogenetic data, and it appears that the traditional taxonomic emphasis on these plastic characters has obscured evolutionary relationships between these, and possibly other, Hyriidae. 相似文献
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Arthur E. Bogan 《Hydrobiologia》2008,595(1):139-147
The term freshwater bivalve is very inclusive and not very informative. There are representatives of at least 19 families
that have at least one representative living in freshwater. This suggests at least 14 different invasions of freshwater. At
least nine families have small to large radiations in the freshwater environment: Corbiculidae, Sphaeriidae, Dreissenidae,
and the unioniforme families: Hyriidae, Margaritiferidae, Unionidae, Etheriidae, Iridinidae, and Mycetopodidae. The unioniforme
families contain at least 180 genera and about 800 species. This order is characterized by the unique parasitic larval stage
on the gills, fins or the body of a particular host fish. This order of freshwater bivalves is suffering a very high rate
of extinction, with about 37 species considered presumed extinct in North America alone. The level of endangerment and extinction
facing these animals is primarily the result of habitat destruction or modification.
Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens
Freshwater Animal Diversity Assessment 相似文献
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The freshwater mussel Hyridella depressa is an important component of the macrobiota of freshwater systems of south-eastern
Australia. This species has declined in river habitats but is abundant in impounded water storages. Reproduction of river
and lake populations of H. depressa was investigated to document details of their gametogenic cycle and to determine when
the females incubate embryos in their gill marsupia. Four populations in Lake Burragorang and two populations in the Hawkesbury-Nepean
River were studied over two breeding seasons. Reproduction was documented by anatomical and histological examination of the
gonads. The study sites differed in anthropogenic influence and trophic status and the influence of these factors on reproduction
in H. depressa was assessed. A skewed sex ratio in favour of females was common in the populations and histology revealed
that some of these females were microhermaphrodites. It appears that sexuality in H. depressa is labile with the potential
for self-fertilisation by individuals that largely function as females. H. depressa is a long-term brooder with progeny present
in the marsupia for up to eight months of the year from mid-winter to late summer. Across all sites brooding started in July
or August and finished in January or February of the following year. In parallel with the prolonged spawning pattern, gametogenesis
in H. depressa was continuous. At the eutrophic sites the gonads contained advanced gametes throughout the year. H. depressa
at these sites had a high annual reproductive output with the females producing several clutches each year. In contrast, gametogenesis
in mussels at the oligotrophic sites was more seasonal. At one of the oligotrophic sites reproductive failure was common and
in 1996 most females failed to brood a single clutch. Implications of this research for conservation of H. depressa are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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《Geobios》2020
Two new taxa of freshwater mussels (Bivalvia: Unionida) from the Aptian Crato Formation of the Araripe Basin, NE Brazil, are described. The fossil bivalves are confined to 30- to 130-cm-thick bioturbated mudstones overlying the fossil-rich laminated limestones of the Crato Formation Konservat-Lagerstätte. Individuals are often preserved with closed or splayed articulated valves, some of them potentially in life position, forming an autochthonous to parautochthonous assemblage. Monginellopsis bellaradiata nov. gen., nov. sp. shares key characters with the Trigonioidoidea: (i) the anterior pedal retractor muscle scar is clearly separated from the anterior adductor muscle scar; (ii) the shell has fold-like radial ribs on the posterior half; (iii) a right valve anterior tooth has a striated facet. Araripenaia elliptica nov. gen., nov. sp. is the most abundant and widely distributed unionid of the Crato Formation. Its ornament of anterior inverted V-shaped riblets, and central and posterior radial and sub-radial riblets resembles modern and fossil Hyriidae from the Americas, but also Trigonioidoidea from Eurasia. Its dentition of two smooth anterior pseudocardinals and two smooth posterior laterals in each valve provides no further clues for systematic assignment; muscle scars are not preserved. Assignment to the Hyriidae would make Araripenaia the oldest member of this family known from South America. Moreover, this bivalve assemblage of trigonioidoidids, hyriids, and previously reported silesunionoids suggests palaeobiogeographic links to other areas in both Gondwana and Laurasia. 相似文献
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