Mussel of the Month

At the close of 2017, there was an explosion of new freshwater mussel genera. Counting on our fingers, we have gained 8 new ones on our checklist, principally from two articles: Bolotov et al. (2017) and Williams et al. (2017). Parvaspina and Trapezidens where described as new, pulling species from Pleurobema and Trapezoideus, respectively. The other six were raised from synonymy to accommodate new classifications:

• Utterbackiana from Utterbackia,
• Reginaia from Fusconaia,
• Eurynaia from Elliptio,
• Bineurus and Monodontina from Pseudodon, and
• Sinohyriopsis from Hyriopsis.

We know of still more genus-level revisions coming down the pike.

Sinohyriopsis cumingii was removed from the genus Hyriopsis because true Hyriopsis are classified in the subfamily Rectidentinae, whereas phylogenetic analysis places S. cumingii with the genera of the Gonideinae (Lopes-Lima et al., 2017).

Although the taxonomy of this mussel was largely a guess until recently, it is actually a well-studied mollusk. For example, of all freshwater mussels, Sinohyriopsis cumingii has the richest set of sequences available on Genbank (155). That is, there are sequences for more than 150 different named genes and haplotypes owing to the large number of nuclear protein coding loci that have been characterized. References to many of the studies associated with those sequences can be found here. Sinohyriopsis schlegelii is in 2nd place with 48, and Cristaria plicata has 40. Compare those with 7 for Lampsilis cardium.