''Musculus somaliensis'' is an extinct

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of small saltwater mussel, a

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

marine bivalve mollusc in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Mytilidae Mytilidae are a family of small to large marine and brackish-water bivalve molluscs in the order Mytilida. One of the genera, '' Limnoperna'', even inhabits freshwater environments. The order has only this one family which contains some 52 gener ...

, the mussels. The size, shape and sometimes color of these fossils are reminiscent of a pistachio nut.

Distribution

''Musculus somaliensis'' lived during the late

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

, possibly throughout the Ethiopian Faunal Province, which consisted of Ethiopia, Somalia, Jordan, Yemen, Kenya, Madagascar, Saudi Arabia, and Tunisia according to Kiessling.W. Kiessling, D. K. Pandey, M. Schemm-Gregory, H. Mewis, and M. Aberhan. 2011. "Marine benthic invertebrates from the Upper Jurassic of northern Ethiopia and their biogeographic affinities". ''Journal of African Earth Sciences'' 59:195-214 Fossils of ''M. somaliensis'' are known from the Upper Jurassic of Somalia (

Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 166.1 ± 4.0 Ma (million years ago) and 163.5 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...

/ Oxfordian in Jirba Range, Biyo Dader Tug, Bihendula), Ethiopia (Callovian in Mt. Guresu, Marda Pass; Late Oxfordian in

Antalo Limestone The Antalo Limestone, also known as the Antalo Sequence, is a geological formation in Ethiopia. It is between 300 and 800 metres thick and comprises fossiliferous limestones and marls that were deposited in a reef. Marine microfossils have shown ...

north of Mekele) and Tunisia (Late Callovian/Oxfordian in Ghomrassen; Middle Callovian/Late Callovian in Ksar Ben Soltane, Krechem el Miit; Callovian/Early Oxfordian in Foum Tataouine Post Optique; Callovian/Oxfordian in Bir Remtha, Faljet Jdar/Ed-DghaghraS. Holzapfel. 1998. Palökologie benthischer Faunengemeinschaften und Taxonomie der Bivalven im Jura von Südtunesien. Beringeria - Würzburger geowissenschaftliche Mitteilungen (22)1-199 ).Paleobiology Database

Habitat

The fossil locations cited were tropical shallow seas, where this mussel lived as a stationary epifaunal suspension feeder.

Description

''Musculus somaliensis'' has a modioliform shape with a straight to weakly convex dorsal margin. A rounded carina runs from the umbo to the postero-ventral corner of the shell, forming an angle of c. 45° with the dorsal margin, ventrally followed by a shallow sulcus. The antero-ventral part of the shell is inflated and has a convex antero-ventral margin. Its carina is more strongly curved and in its distal part forms an angle of c. 60–70° with the dorsal margin. A sulcus is absent, the antero-ventral part is low and limited by a concave antero-ventral margin.

References

{{Taxonbar, from=Q6940416 Mytilidae Jurassic bivalves Fossil taxa described in 1935 Molluscs described in 1935 Jurassic animals of Africa