Vasticardium luteomarginatum
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Vasticardium luteomarginatum , Maldives |
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| Vasticardium luteomarginatum | ||||||||||||
| ( Voskuil & Onverwagt , 1991) |
The Vasticardium luteomarginatum (synonym: Trachycardium luteomarginatum ) is a type of mussel from the family of cockles (Cardiidae), which belongs to the order Cardiida .
features
The case is relatively large, up to approx. 9 cm high and 4 to 5 cm wide, oblong-oval and strongly arched. It is set with 32 to 35 low and rounded, wide ribs, which are provided with thorns on the front third of the case. In the back, the ribs become flatter. The areas between the ribs are about half as wide as the ribs themselves in the middle of the case, slightly narrower than half in the front and rear case areas. The ribs are crossed by faint strips of growth. The color varies between reddish-brown and yellow-brown bands. The shell is relatively thick. The lunula is relatively large; it is slightly wider on the right flap than on the left flap. The edge of the flaps is serrated; only almost straight at the front edge of the case. In the front half, the ribs can still be seen inside. The lock is strong. In the left valve it consists of two main or lateral teeth, of which the anterior is large and triangular, the posterior is somewhat smaller, as well as an anterior and posterior lateral or lateral tooth. The anterior lateral tooth is relatively high and narrowed, the posterior lateral tooth is small and close to the posterior margin. The proportions of the two main or cardinal teeth of the right valve are the opposite of those of the left valve; the front one is very small, the rear one very large. There are two anterior lateral teeth, the ventral one large and the dorsal very small, as well as a strong posterior lateral tooth.
Way of life, occurrence and distribution
Vasticardium luteomarginatum lives shallowly buried in sandy sediments in shallow water. It occurs mainly in the eastern Ind and in the western Pacific ( Maldives , Thailand , Singapore and Indonesia ).
Systematics
Vasticardium luteomarginatum is included in the Vasticardium orbita complex. This is a close family group within the subfamily Trachycardiinae, to which the two species Vasticardium orbita and Vasticardium luteomarginatum and their subspecies belong. The species Vasticardium orbita (Broderip & Sowerby, 1833) are assigned the subspecies orbita , hawaiiensis , mendanaense and philippinense , all of which are native to the Pacific. To Vasticardium luteomarginatum (Voskuil and Onverwagt, 1991), are mainly occurring in the Indian Ocean subspecies luteomarginatum , marerubrum (from the Red Sea ) and insular (from the west coast of Madagascar ). Since the distribution areas of the two species do not substantially overlap ( allopatry ) or indistinguishable forms occur in the area of overlap, it is possible that all forms could be geographically divided subspecies of a single species. This is supported by the fact that their youth stages have the same housing morphology. This only differentiates in the course of ontogeny with increasing age in the shape of the housing and in the structure of the radial ribs.
literature
- RPA Voskuil and WJH Onverwagt: Studies on Cardiidae. 4. The taxonomy of the genus Trachycardium (Part 1) with description of three new species. Vita marina, 41 (2): 56-72, The Hague 1991 ZDB -ID 919455-1
Individual evidence
- ^ J. Vidal: Large Trachycardiinae from the Indo-West Pacific: The group of Vasticardium orbita (Broderip & Sowerby, 1833) (Mollusca, Cardiidae). Molluscan Research, Volume 18, Issue 1, pp. 11-32, April 30, 1997 abstract
