We chose Aculamprotula zonata as Mussel of the Month because 1) it is a good-looking shell, and 2) we are kind of surprised that — with all the active reclassification of freshwater mussel genera — the name Aculamprotula is still in use.
Aculamprotula Wu, Liang, Wang & Ouyang, 1999 was described to account for some species of the old Lamprotula sensu lato having triangular glochidia with hooks brooded only in the outer demibranches while other species of Lamprotula sensu stricto have unhooked glochidia brooded in all four demibranches. The ectobranchus species with hooked glochidia were moved to Aculamprotula and classified in the Unioninae, while the tetragenous species with unhooked glochidia stayed in Lamprotula in the subfamily Gonideinae (Graf & Cummings, 2021). This first-splitting of Lamprotula didn’t really take hold with the global mussel community until Pfeiffer & Graf (2013) reanalyzed the phylogenetic data published by Zhou et al. (2007).
In 2018, Huang et al. found that some of those species still left in Lamprotula actually belonged to a different family. They were transferred to the genus Gibbosula and reclassified from the Unionidae to the Margaritiferidae (Graf & Cummings, 2021).
So, there has been lots of attention paid to the species of the former Lamprotula s.l., but there is still work to do.
As we pointed out back in August 2013 when Aculamprotula fibrosa was Mussel of the Month, the type species of Lamprotula, Chama plumbea Dillwyn, 1817, is only known from a figure in Chemnitz (1795, figs. 1991-1992). Not only are we unsure where that species is from, but the shell looks a lot more like this month’s mussel, Aculamprotula zonata — which itself looks like other species of Aculamprotula. Maybe Aculamprotula should really be the one called Lamprotula, and the current Lamprotula s.s. should be called something else.
We don’t even really know if Aculamprotula zonata is a “real” species. Pfeiffer & Graf (2013) found the mtDNA sequences attributed to that species to be only 1% different from those labeled A. fibrosa and A. tientsinensis in Genbank. Whether or not Aculamprotula zonata (Heude, 1883) is a distinct evolutionary lineage/biological species, the name is pre-occupied (i.e., a junior homonym) of Unio marginalis var. zonata Hanley & Theobald, 1872 (= Trapezidens scutum) and as such is permanently invalid — without another nominal species name in synonymy to replace it.
If Aculamprotula zonata is not sunk into synonymy with another species, it needs to be given a new name — and maybe that new name will eventually be transferred back to Lamprotula! |
