Granulated spatula

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Granulated spatula
Granulated spatula (Thracia villosiuscula) (from MacGillivray 1827: Plate 1, Fig. 10, 11 [1])

Granulated spatula ( Thracia villosiuscula ) (from MacGillivray 1827: Plate 1, Fig. 10, 11)

Systematics
Superordinate : Anomalodesmata
Order :
Superfamily : Thracioidea
Family : Spatula clams (Thraciidae)
Genre : Thracia
Type : Granulated spatula
Scientific name
Thracia villosiuscula
( MacGillivray , 1827)

The Granulated Spatelmuschel ( Thracia villosiuscula ) is a shell - type from the family of Spatelmuscheln (Thraciidae).

features

The unevenly hinged, only moderately inflated housing is up to 30 mm long. The right flap is slightly larger and more arched than the left flap. It is unequal, with the vertebrae sitting behind the midline. It is oblong-ovoid in outline. Nordsieck gives a ratio of length to width to thickness of 20-25 mm to 14-17 mm to 7-8 mm. The posterior dorsal margin is straight to very slightly concave. The rear edge appears trimmed at right angles to the longitudinal axis. The anterior dorsal margin is initially also straight and merges into the broadly rounded anterior margin. The ventral margin is only slightly arched, in some specimens almost straight. The ligament is external and internal. The external ligament is short and lies behind the vertebrae. The inner ligament is thick and lies in a narrow, triangular pit (each in the right and left flaps) under the external ligament in the lock plate. The lithodesm is short, cone-shaped and sits in front of the ligament. It fits into a pit in the other flap. The anterior sphincter is long and thin, the posterior sphincter is somewhat broader and rounded and triangular. The jacket bay is U-shaped, very deep and extends to the level of the front end of the inner ligament.

The whitish skin is thin and fragile. The ornamentation consists of fine lines and ribs parallel to the edge. The surface is also finely grained. The grain is better visible under the magnifying glass and is particularly pronounced in the rear part of the case. The light brown periostracum is a very thin, organic membrane. The inner edge of the case is smooth. The inside of the case is glossy white.

Similar species

The granulated spatula ( Thracia villosiuscula ) is very difficult to distinguish from the white bean ( Thracia phaseolina ). In the latter type, the rear edge is trimmed backwards at an angle. A typical feature of the granulated spatula is the granular surface, which can only be seen with a magnifying glass. The long spatula ( Thracia pubescens ) is significantly larger.

Geographical distribution and habitat

The distribution area of ​​the species extends from the eastern North Sea (Sweden, Norway) to the British Isles and the Channel. The depth distribution begins from the deeper tidal area to the middle of the shelf (about 60 meters). It prefers coarse sand, fine gravel to coarse gravel soils.

Taxonomy

The taxon was published by William MacGillivray in 1827 under the original combination Anatina villosiuscula . It is generally recognized as a valid species.

supporting documents

literature

  • Paul Chambers: British Seashells: A Guide for Collectors and Beachcombers. 233 pp. Remember When, Barnsley 2009 ISBN 978-1-84468-051-1 ; 1-8446-8051-7 Preview on Google Books (p. 196)
  • Fritz Gosselck, Alexander Darr, Jürgen HJ Jungbluth, Michael Zettler: common names for mollusks of the sea and brackish water in Germany. Mollusca, 27 (1): 3-32, 2009 PDF (p. 29)
  • Fritz Nordsieck : The European sea shells (Bivalvia). From the Arctic Ocean to Cape Verde, the Mediterranean Sea and the Black Sea. 256 p., Gustav Fischer Verlag, Stuttgart 1969 (p. 160 as Thracia papyracea villosiuscula )
  • Guido Poppe. Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3925919104 (138)
  • Peter J. Hayward, John S. Ryland: Handbook of the Marine Fauna of North-West Europe. X + 800 S., University Press, Oxford 2017 ISBN 978-0-19-954944-3 Preview on Google Books (p. 566)

On-line

Individual evidence

  1. ^ A b William MacGillivray: Description of Anatina villosiuscula, a new species, and of Venerupis nucleus, a species new to the British fauna. The Edinburgh New Philosophical Journal, 2: 370-372, Edinburgh, 1827 Online at www.biodiversitylibrary.org Plate 1
  2. ↑ MolluscaBase: Thracia villosiuscula (MacGillivray, 1827)

Web links

Commons : Granulated spatula ( Thracia villosiuscula )  - Collection of images, videos and audio files