Shell equivalve, slightly inequilateral, subovate to subtriangular, with a rounded ventral margin and prominent umbones; sculpture mainly concentric; valves not gaping; ligament external; no pallial sinus.
Astarte Sowerby, 1816:
Shell medium-sized, thick, moderately convex, almost equilateral; the width is at least equal to the height; sculpture of smooth concentric plicae; periostracum brown; hinge: one large cardinal in the right valve, two smaller cardinals in the left, no laterals; inside of margins crenulated; muscle scars deeply impressed.
Digitaria Gray, 1851:
« Valves rotund, shell small, lentiform, hinge as in Gonilia, having the larger cardinals bifid; surface obliquely, arcuately sulcate, the sulci grooving more or less the inner margin tangentially. » – W. H. Dall: “Synopsis of the family Astartidae”, Proceedings of the United States National Museum vol.26, Washington 1903, p.936. The genus bears the same name than a group of plants of the family Poaceae (R.Br.) Barnh., 1895: Digitaria Haller, 1768.
Gonilia Gray, 1851:
« Small, lentiform, hinge as in Astarte; disk with divaricate ribbing centrally. » – Ibid. The genus is monotypic.
Goodallia Gray, 1851:
« Small, smooth, the hinge teeth reduced by the absence of the anterior or posterior right cardinal or both of them; inner margins crenate at resting stages only. » – Ibid.
