Atrina maura

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Atrina maura
Atrina maura

Atrina maura

Systematics
Subclass : Pteriomorphia
Order : Ostreida
Superfamily : Pinnoidea
Family : Pen clams (Pinnidae)
Genre : Atrina
Type : Atrina maura
Scientific name
Atrina maura
( GB Sowerby I , 1835)

Atrina maura is a type of mussel from the pen mussel family(Pinnidae). It occurs in the east Pacific coast from Baja California to Peru .

features

The equally-flattened, somewhat flattened housing is elongated-triangular or fan-shaped in outline. It becomes up to 60 cm long. However, the specimens from Peru are significantly larger than the specimens from Baja California, which are only about 22.5 cm long. The case is comparatively wide in relation to its length; the longitude / latitude index is about 1.8. The dorsal margin is straight to slightly concave. The ventral edge is curved straight to slightly concave at the front end, towards the rear end it is convex. The mother-of-pearl layer reaches up to three quarters of the rear end. The anterior sphincter is small and rounded, and sits almost directly on the anterior end. The posterior sphincter is elongated and rounded and sits clearly within the layer of mother-of-pearl (upper end at about two thirds).

On the surface are 8 to 20 (or 9 to 16 according to Coan et al.) Radial ribs that are widely spaced apart, most of which are studded with open, tubular thorns pointing backwards. The longitudinal ribs are missing on the ventral housing field; there are only somewhat irregular, coarse growth strips or bulges parallel to the edge. Juvenile specimens have fewer ribs. New ribs are switched on between the primary ribs. Juvenile cases have thin, fragile shells that are translucent. The color varies from light brown to dark brown to almost black.

Similar species

Atrina maura has 9 to 16 ribs with tubular spines, Atrina texta on the other hand has about 30 very fine, widely spaced, serrated ribs. Atrina oldroydii , on the other hand, has only weak ribs with weak strips parallel to the edge.

Geographical distribution and habitat

The distribution area of Atrina maura extends from Baja California (from 24.6 ° N) over the Gulf of California (up to 31.4 ° N), Panama (7 ° N, type locality) to Peru (7 ° S).

The animals stick vertically with the front end first and attached with byssus in muddy, silty and sandy sediments from the tidal range to about 25 meters water depth. Atrina maura is also found in the mangrove .

The species is probably not segregated like other types of pen mussels, but a protandric hermaphrodite .

Taxonomy

The species was set up in 1835 by George Brettingham Sowerby I in the original combination Pinna maura . Today (2016) it is generally accepted in the genus Atrina . Peter Schultz and Markus Huber place in the sub-genus Servatrina Iredale, 1939, but the sub-genre of Atrina is not generally recognized.

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: 1-164, Hackenheim, ConchBooks, 2013 PDF (summary) (pp. 50–52)

Individual evidence

  1. ↑ Marian A. Camacho-Mondragón, Bertha P. Ceballos-Vázquez, Alma R. Rivera-Camacho and Marcial Arellano-Martínez: Unnoticed Sex Change in Atrina maura (Bivalvia: Pinnidae): Histological and Size Structure Evidence. American Malacological Bulletin 33 (1): 43-51, 2015 doi : 10.4003 / 006.033.0102
  2. ↑ George Brettingham Sowerby I: Characters and observations on new genera and species of Mollusca and Conchifera collected by Mr. Cuming. Gender Pinna. Proceedings of the Zoological Society of London, 3: 84-85, London 1835 Online at www.biodiversitylibrary.org
  3. ↑ MolluscaBase: Atrina maura (GB Sowerby I, 1835)

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