Manuel Lopes-Lima, Lyubov Burlakova, Alexander Karatayev, André Gomes-dos-Santos, Alexandra Zieritz, Elsa Froufe and Arthur E. Bogan have published a new paper (2019) on molecular systematics with some morphological and geographic analyses regarding the mussel tribe Quadrulini. Many new mussels, mainly from Texas, were part of the analyses; thus, this paper has particular relevance to our understanding of mussels in Louisiana. In the end, the results indicate that Cyclonaias mortoni and C. refulgens are conspecific with C. pustulosa. Further, Q. apiculata is conspecific with Q. quadrula. And finally, Q. nobilis is now placed in the genus Tritogonia. During the last few decades, the genus Quadrula sensu lato has received much attention. As it stands now, there are 4 genera in Louisiana that belong to this group: Quadrula, Cyclonaias, Theliderma and Tritogonia. At this site, we are very interested in the mites that occur in these mussels.
Lopes‐Lima, M, L. Burlakova, A. Karatayev, A. Gomes-dos-Santos, A. Zieritz, E. Froufe and A. E. Bogan. Revisiting the North American freshwater mussel genus Quadrula sensu lato (Bivalvia Unionidae): Phylogeny, taxonomy and species delineation. Zool Scr. 2019; 00: 1–24.
https://doi.org/10.1111/zsc.12344
The mites of the Quadrulini include mites that are found in members of the other tribes, namely Plectomerus dombeyanus, Obliquaria reflexa and Amblema plicata. The mites include the array of species described by Mitchell and Wilson in 1965 from Tennessee mussels. The species of interest are:
• U. tupara—a common parasite of Megalonaias, Amblema and Plectomerus, members of the Quadrulini, Amblemini and Lampsilini, respectively. This mite probably resembles the ancestors of all the following mites in our list.
• U. stricta—a parasite of the genus Uniomerus in Louisiana and much of the Mississippi Interior Basin and Texas.
• U. amandita—a related mite that appears to be mainly a parasite of Amblema.
• U. vikitra—a common parasite of Cyclonaias spp., Quadrula spp., & Tritogonia nobilis; this species also occurs in Obliquaria reflexa–a lampsilinine.
• U. vikitrella—a species similar to U. vikitra but small and less setose with similar host spectrum.
• U. sakantaka—a common parasite of Cyclonaias spp. and Theliderma spp.
• U. vamana—a common parasite of Tritogonia verrucosa.
These mites, currently assigned to the subgenus Unionicolides, were the focus of much my research for my dissertation in the 1970s and into the 1980s. Three other groups of these mites in North America infest the Lampsilini, the Pleurobemini and the Anodontini, respectively. Many of these mite species are widely distributed both in geographic distributions and host associations; thus, there are great opportunities for cryptic species among these named taxa. In many cases, I described these species using morphological character-states. And the variation was great and mesmerizing; thus, I would not be surprised to see additional species. The latest evidence on the several cryptic species within the currently named U. hoesei in the Lampsilini in the Calcasieu River leads me to suspect that many of my species are indeed groups of cryptic species to be discerned by genetic analyses—not unlike what it apparent in the Quadrula sensu lato in this and other papers.
An updated list of the mussels of Louisiana is attached. The changes in the names of these mussels reduces the number of species currently recognized in Louisiana. However, new questions arise as the biogeography of Louisiana mussels in the genus Cyclonaias, namely C. pustulosa, C. mortoni and C. refulgens, and the answers to these questions may change some of the conservation considerations. Likewise, separation of Quadrula quadrula (both Q. quadrula and Q. apiculata sensu lato) from Tritogonia nobilis presents some challenge, and this certainly changes many records in my 1993 book, since most of the Q. quadrula sensu lato in Louisiana were T. nobilis, and some of the conservation considerations.
I hope to do a new book on mussels of Louisiana and a book on the mites of the Unionicolides–these 2 topics have been foci of interest for me for nearly 50 years. And much has changed in their nomenclature and their distributions in the state. We are in a dire need for a full state survey of mussels. Fortunately, we now have a better handle on the systematics of the mussels (and the mites), but much remains to be unraveled and revealed.
Unionicola 