Mussel of the Month

UMMZ 232482. [Abu Rauwash], west of Cairo, Egypt. Kuntz, 1950!

Nitia teretiuscula is found in the Nile Basin of Africa. What interests us about this mussel this month is that it served as the hard working sister-group to Coelatura and the other Afrotropical unionid species in a recent phylogenetic analysis.

DLG, Anthony Geneva, John Pfeiffer and Alex Chilala just published a new paper on the phylogenetic relationships of the mussels of Lake Mweru. The paper focuses on two monotypic genera, Prisodontopsis and Mweruella, and the upshot was that the two taxa are sister to each other (with some interesting complications). Graf et al. (2014) concluded that there was really just one genus with two species, Prisodontopsis aviculaeformis and P. mweruensis. With the help of Nitia to calibrate the molecular clock, they were able to determine a Pleistocene age for the divergence of the two Lake Mweru species. Lake Mweru doesn't have much of a fossil record, but Nitia is well known from the Rift Valley, which does (Van Damme & Pickford, 2010).

Let's all take this month and celebrate little Nitia teretiuscula, the horologer.

Classification:

Phylum Mollusca
Class Bivalvia
Subclass Palaeoheterodonta
Order Unionoida

Family UNIONIDAE Rafinesque, 1820
Subfamily PARREYSIINAE Henderson, 1935
Tribe COELATURINI Modell, 1942

Genus Nitia Pallary, 1924

Species Nitia teretiuscula (Philippi, 1847)