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Duck Clam
Mactridae, common name the trough shells or duck clams, is a family of saltwater clams, marine bivalve mollusks in the order Venerida. Description These clams have two short siphons, each with a horny sheath. The shell is shaped like a rounded-cornered equilateral triangle and there is a slight gape at the posterior. Each valve bears two cardinal teeth with four lateral teeth on the right valve and two on the left. The foot is white and wedge-shaped. They mostly inhabit the neritic zone. Ecology Trough shells burrow in sand or fine gravel and never in muddy substrates. Subfamilies and genera According to the World Register of Marine Species (2025), this family contains 56 genera and is split into the following subfamilies: Subfamily Darininae * '' Darcinia'' Clark, 1946 * '' Darina'' J. E. Gray, 1853 Subfamily Lutrariinae * '' Eastonia'' J. E. Gray, 1853 * '' Heterocardia'' Deshayes, 1855 * ''Lutraria'' Lamarck, 1799 * '' Meropesta'' Iredale, 1929 * '' Standella'' J. E. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ninth and longest geological period of the entire Phanerozoic. The name is derived from the Latin , 'chalk', which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation . The Cretaceous was a period with a relatively warm climate, resulting in high Sea level#Local and eustatic, eustatic sea levels that created numerous shallow Inland sea (geology), inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was largely ice-free, although there is some evidence of brief periods of glaciation during the cooler first half, and forests extended to the poles. Many of the dominant taxonomic gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zenatia
''Zenatia'' is a genus of medium-sized clams, marine bivalve molluscs in the family Mactridae. Distribution This genus is endemic to New Zealand. Species Species in the genus ''Zenatia'' include: * '' Zenatia acinaces'' ( Quoy and Gaimard Joseph Paul Gaimard (31 January 1793 – 10 December 1858) was a French naval surgeon and naturalist. Biography Gaimard was born at Saint-Zacharie on January 31, 1793. He studied medicine at the naval medical school in Toulon, subsequent ...) * '' Zenatia zelandica'' Gray References * Powell A. W. B., ''New Zealand Mollusca'', William Collins Publishers Ltd, Auckland, New Zealand 1979 Mactridae Bivalves of New Zealand Bivalve genera {{bivalve-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tresus
''Tresus'' is a genus of saltwater clams, marine bivalve mollusks in the family Mactridae. Many of them are known under the common name the horse clam or as species of gaper clam. They are similar to geoducks. Species Species within the genus ''Tresus'' include: * '' Tresus allomyax'' (Coan & Scott, 2000) – strange gaper * '' Tresus capax'' (Gould, 1850) – fat gaper * '' Tresus keenae'' (Kuroda & Habe, 1950) – mirugai clam * '' Tresus nuttallii'' (Conrad, 1837) – Pacific gaper * '' Tresus pajaroanus'' (Conrad, 1857) – lost gaper Habitat These species' habitat is the lower intertidal zones on out to waters as deep as 50–60 feet (13–15 m). They prefer sand, mud, and gravel substrates, normally burying themselves 12–16 inches (30–41 cm), so they are much easier to dig than geoducks. Their preferred substrates are also preferred by butter and littleneck clams, so horse clams are often taken incidentally in commercial harvesting. ''Tresus'' cla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lutraria
''Lutraria'' is a genus of medium-sized marine bivalve mollusks or clams, commonly known as otter shells. Characteristics Members of this genus have large, elongated oval shells with two equal sized valves. The anterior end is somewhat sharply curved but the posterior end is more rounded. The valves gape slightly at both ends, more so at the posterior end. The shell is fairly thick and is sculptured with fine concentric lines corresponding to periods of growth. The basic colour is white and the periostracum is brown, but the latter is usually abraded. The interior surface of the valves is glossy white. The beaks are blunt and situated slightly closer to the anterior end. The ligament is small and largely internal. The foot is small and the siphons are long and are housed in a common horny sheath for most of their length. Biology These mollusks live buried in sand to a depth of about , usually below low water mark, with their siphons extended to the sea bed. As they grow they b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
