Mussel of the Month

Monocondylaea paraguayana was Mussel of the Month back in September 2008, when we took the opportunity to discuss the changing diversity estimates of Neotropical freshwater mussels since the work of Haas (1969). There was a glimmer of taxonomic lumping by Simone (2006), and then a rebound requiring re-splitting from Pereira et al. (2014). Back in 2008, the thinking was that there were 3 species in the genus Monocondylaea. Today, we have eight (Graf & Cummings, 2021).

Despite the apparent taxonomic interest in Monocondylaea and the other genera of the Mycetopodidae, there hasn’t been much progress toward resting the classification of the family on a firm phylogenetic footing. The Monocondylaeinae is one of four subfamilies of the Mycetopodidae — the 2nd most species-rich with 18, and with 6 genera, it exceeds the genus-richness of the other 3 subfamilies combined. But, as is summarized on the cladomics page for the subfamily, no phylogenetic analysis has included more than two species of monocondylaeines* and never two in the same genus. Only weak tests the monophyly of the subfamily are available (and even then, it usually isn't recovered as monophyletic), and there has been no test of the monophyly of Monocondylaea, the most species-rich genus.

The state of cladistic knowledge isn’t much better for the Mycetopodidae itself. Although the family has more than 50 species in 11 genera, no phylogenetic analysis has included more than five species or represented more than two of the subfamilies! Are mycetopodids actually even a thing?**

We feel pretty confident that at least Monocondylaea minuana is a thing, and it is our current Mussel of the Month.

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* As of this writing, the word “monocondylaeines” is unknown to Google.com.
** It seems like that should be answered before anyone wants the revise taxonomy to claim that Mulleria is a mycetopodid and therefore mycetopodids are "mulleriids."