Atrina oldroydii
| Atrina oldroydii | ||||||||||||
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| Scientific name | ||||||||||||
| Atrina oldroydii | ||||||||||||
| Dall , 1901 |
Atrina oldroydii is a mussel species from the pen mussel family(Pinnidae). It occurs on the coasts of the Eastern Pacific from southern California to Chile.
features
The same-hinged, inflated housing is triangular-ham-shaped; it becomes up to 36 cm long. It is relatively wide in relation to its length (L / W ratio under 2). The vertebrae are very small and sit at the front end. The dorsal margin is straight, the ventral margin near the anterior margin is concave, towards the rear end it is straight to slightly convex. The rear edge is well rounded and sloping from the dorsal edge to the ventral edge. From the vertebra to the posterior ventral margin, a more pronounced keel runs centrally and curved.
The mother-of-pearl layer extends to around three quarters of the length of the case (seen from the front edge). The anterior sphincter is small and elongated and sits directly on the front edge (“tip” of the housing). The posterior sphincter is very large and elliptical across. It sits clearly away from the rear edge in the mother-of-pearl layer.
The shell is comparatively thick, translucent, solid-walled and heavy. The color varies from horn-brown, brown to black-gray with individual reddish-brown areas. The surface is shiny. On the three quarters of the surface seen from the dorsal margin, there are around 40 fine longitudinal ribs, which are crossed by more or less strong growth strips and also interrupted by strong indentations parallel to the edge at irregular intervals. Occasionally there are some short, triangular thorns on the ribs. Usually the radial ribs are lost on the last quarter before the rear edge. The ventral field (last quarter before the ventral margin), on the other hand, shows only coarse asymptotic growth strips.
Similar species
Atrina oldroydii has only weak ribs that intersect with weak strips parallel to the edge. Atrina texta has about 30 very fine, widely spaced, serrated ribs, Atrina maura 9 to 16 ribs with tubular spines.
Geographical distribution and habitat
The distribution area extends from southern California ( San Pedro Bay , 33.7 ° N) and the Gulf of California to Chile ( Antofagasta , 23.5 ° S).
Atrina oldroydii lives vertically with the front edge attached with byssus facing down in the muddy sediment from approx. 2 to 160 meters water depth.
Taxonomy
The species was described in 1901 by William Healey Dall . Today it is generally recognized as a valid species. Peter Schultz and Markus Huber add the species to the subgenus Servatrina Iredale, 1939. The subgenus classification of Atrina proposed by Schultz and Huber is not generally accepted.
supporting documents
literature
- Eugene V. Coan, Paul Valentich-Scott: Bivalve Seashells of Tropical West America marine Bivalve mollusks from Baja california to Northern Perú. Part 1,598 pp., Santa Barbara Museum of Natural History, Santa Barbara 2012 ISBN 978-0-936494-43-2 (p. 226)
- Peter Schultz, Markus Huber: Revision of the worldwide Recent Pinnidae and some remarks on fossil European Pinnidae. Acta Conchyliorum, 13: 164 S., Hackenheim, ConchBooks, 2013 PDF (summary) (pp. 52–54)
Individual evidence
- ^ William Healey Dall: A new Pinna from California. The Nautilus, 14 (12): 142-143, 1901 online at www.biodiversitylibrary.org
- ↑ a b MolluscaBase: Atrina oldroydii Dall, 1901