elongate Acrosterigma
Acrosterigma extremattenuatum
Acrosterigma extremattenuatum is a large and striking subtidal species (2-78 m dead, 20 m live) with spathulate shape ventrally and cream-yellow exterior coloration with red- brown chevron markings. It is a Dampierian endemic, found from northern WA (Ningaloo) to Queensland (Torres Strait). The name extremattenuatum refers to the more pronounced elongate and attenuate shape of this species compared to A. attenuatum.
Morphology
It is a large and elongate shell for the genus (61.3 mm length). It is solid, elongately ovate, inequilateral and strongly elongate (H/L 1.63-1.95, n = 16, H 40.8-61.3 mm). The species is highly attenuate towards the umbones and moderately inflated. Exterior glossy and almost smooth with weak ribbing (56.5 mean number, ranging from 51-59). The main shell feature that differentiates this species from similar A. attenuatum is that the new species is more elongate and attenuate less inflated, differs in coloration, with prominent red brown chevrons lacking in A. attenuatum and a smaller maximum size.
Evolution
Little is known about the relationship of this species to other members of the genus.
Behaviour
This species, like all cardiids, is shallowly infaunal and will reburrow if disturbed.
Method of reproduction
Broadcast spawner.
Habitat
Marine
Subtidal infaunal in sand, silt
Distribution
Indo west Pacific. In northern WA, restricted to inner and mid-continental shelf where it has been found most frequently off the Pilbara coast.
| Kingdom: | Animalia |
|---|---|
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Subclass: | Heterodonta |
| Superorder: | Imparidentia |
| Superfamily: | Cardioidea |
| Family: | Cardiidae |
| Genus: | Acrosterigma |
| Species: | extremattenuatum |
| Name Published Year: | 2017 |
|---|---|
| Scientific Name Authorship: | ter Poorten & Kirkendale |
| Commercial Impact: | None |
| Conservation Assessment: | Least Concern |
Cite this page
Western Australian Museum Collections https://museum.wa.gov.au/online-collections/names/Acrosterigma-extremattenuatum
Accessed 16 Sep 2025
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