Astarte acuticostata Friele, 1877
Crassatelloidea : Astartidae |
| Tebble name: | n/a |
| Smith & Heppell name: | Tridonta acuticostata (Jeffreys, 1869) |
To size: To 13mm. Shell Structure: Thin, brittle. Equivalve: Equivalve. Equilateral: Inequilateral, the beaks lie approximately 20% of dorsal margin length from anterior. Tumidity: Moderately tumid. Outline: Subtrigonal, anterior distinctly narrowed, height of shell just over 80% of the height. Posterior dorsal margin long, gently sloping, very slightly convex to almost straight; anterior dorsal margin more steeply sloping and conspicuously concave behind the umbo and then straight to the anterior end; anterior end slightly rounded; posterior end truncated/bluntly rounded; ventral margin almost straight; lunule distinct, slightly sunken, heart-shaped, relatively smooth with well defined, raised edges; escutcheon distinct, lanceolate, with very well defined raised edges. Beaks prosogyrous.
Sculpture: Narrow, fine, concentric ridges, cusped in a ventral direction, usually at least 35 in adult individuals. Margin: Smooth. Ligament: Broad, distinct but not prominently raised, runs for approximately one third the length of the escutcheon. Hinge: Heterodont: Robust hinge plate; right valve with 1 solid, relatively curved anterior cardinal tooth, and 1 thin and inconspicuous posterior tooth; left valve with 1 large blunt cardinal tooth, distinctly bifid such that it appears to be 2 teeth, and 1 thin and inconspicuous posterior tooth; the anterior part of the left valve has a long thickened ridge similar to a lateral tooth. Pallial Musculature: Entire. Periostracum: Ranges from yellowy gray to grayish brown. Silky surface texture, microscopically punctate. Colour: White.
Distribution & Ecology
Lives in silty sands on the upper and middle slope, in depths ranging from 400 to 900m.
Depth Range
Continental Margin Zone (200 - 500m)
Bathyal (500 - 2000m)
Additional Information & Related Species
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