Kelliola symmetros

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Kelliola symmetros
Kelliola symmetros, holotype, right flap (inside and outside view)

Kelliola symmetros , holotype, right flap (inside and outside view)

Systematics
Superordinate : Imparidentia
Order :
Superfamily : Galeommatoidea
Family : Lentil mussels (Montacutidae)
Genre : Kelliola
Type : Kelliola symmetros
Scientific name of the  genus
Kelliola
Dall , 1899
Scientific name of the  species
Kelliola symmetros
( Jeffreys , 1876)

Kelliola symmetros is a mussel species from the lentil mussel family(Montacutidae). It is the type and only species of the genus Kelliola Dall, 1899. The species lives commensurately with the irregular sea ​​urchin Aeropsis rostrata (Thomson, 1877).

features

The even-folded, very small, non-inflated housings are approximately egg-shaped, with the front end being slightly more extended than the rear end. They are up to 1.3 mm long and up to 1.0 mm high (length to height ratio 1.3 to 1). The housings are unequal, the orthogyrate vertebrae sit a little behind the middle of the housing length. The anterior, almost straight dorsal margin slopes down towards the rounded anterior end. The posterior dorsal margin is shorter and also slopes more steeply towards the rounded posterior end than the anterior dorsal margin. The ventral margin is well rounded. The lock shows a front, peg-shaped cardinal tooth in the right flap. In front of this number is a slight, elongated, but short indentation (or pit). In the left flap there is only a short, front, marginal flange. Back teeth are missing. The short ligament lies internally on a flat recessed resilifer below and slightly behind the vertebrae.

Kelliola symmetros , holotype, lock and interior view, lv = left valve / left flap, rv = right valve / right flap (from Oliver 2012: Fig. 2)

The whitish skin is thin, fragile and translucent. The ornamentation consists of weak lines parallel to the edge and fine radial stripes on the ventral edge of the case. There may be fine microscopic notches on the ventral margin.

Kelliola symmetros , A: outside view of a left flap, BC: inside view of right and left flap, DE: SEM photos of the lock from right and left flap, FH: SEM photos of the inside of right and left flap as well as an outside view of the left Flap, I: SEM photo of the Prodissoconch, J: SEM photo of the front edge with weak radial ornamentation, K: SEM photo of the housing edge with the incised notches (from Oliver 2012: Fig. 3)

The sphincter muscles are approximately the same size. The edge of the coat has a large opening for the foot. It is fused approximately from the middle of the housing to the rear end, with the exception of a small opening for the outflowing breathing water. The foot has a byssus gland that can produce byssus threads quite actively. The gills consist only of the inner half-leaf.

The Prodissoconch I is only indistinctly separated from the Prodissoconch II. It measures 140 μm in diameter and has a microscopic point structure. The Prodissoconch II, on the other hand, is very clearly separated from the Dissoconch; it measures 380 μm in diameter and is ornamented with growth strips parallel to the edge.

The two egg-shaped sphincter impressions are roughly the same size. The surface line is not indented. The edge of the mantle is usually free. At the lower front end there is a large opening for the foot, at the rear end a very small opening for the water flowing out. The foot has a large "toe" and a small "heel". The byssus gland is functional and produces byssus threads throughout life. The anterior foot retractor muscle inserts above the anterior sphincter muscle, and the posterior foot retractor muscle above the posterior sphincter muscle. The gills consist of a single half-leaf with nine non-bent, rod-shaped filaments (in the largest specimens). Labial palps are present, point forward, but are comparatively small.

Geographical distribution, habitat and way of life

Kelliola symmetros is only known from the Bay of Biscay . It occurs there in abyssal water depths (2,000 m and 6,000 m). The mussel species is associated with the irregular sea urchin Aeropsis rostrata (Wyville Thomson, 1877). The animals are attached to the spines of the sea urchin with byssus threads. The host of Kelliola symmetros is widespread in the North Atlantic.

Taxonomy

The Arttaxon was described by John Gwyn Jeffreys in 1876 ​​as Kellia symmetros . William Healey Dall established the subgenus Kelliola for this species in 1889 . The MolluscaBase accepts Kelliola as a valid genus.

supporting documents

literature

  • P. Graham Oliver: Taxonomy of some Galeommatoidea (Mollusca, Bivalvia) associated with deep-sea echinoids: A reassessment of the bivalve genera Axinodon Verrill & Bush, 1898 and Kelliola Dall, 1899 with descriptions of new genera Syssitomya gen. Nov. and Ptilomyax gen. nov. European Journal of Taxonomy, 12: 1-24, 2012 doi : 10.5852 / ejt.2012.12

On-line

Individual evidence

  1. ^ Jeffreys JG 1876. New and peculiar Mollusca of the Kellia, Lucina, Cyprina and Corbula families procured in the 'Valorous' Expedition. Annals and Magazine of Natural History, ser. 4, 18: 490-499. Online at www.biodiversitylibrary.org (p. 491)
  2. ^ William Healey Dall: Synopsis of the Recent and Tertiary Leptonacea of ​​North America and the West Indies. Proceedings of the United States National Museum, 21 (1177): 873-897, 1899 doi : 10.5479 / si.00963801.21-1177.873 (p. 890)
  3. ↑ MolluscaBase: Kelliola symmetros (Jeffreys, 1876)

Web links

Commons : Kelliola symmetros  - collection of images, videos and audio files