Mussel of the Month

We shined our spotlight on the genus Hamiota 19 years ago when the genus was first described after being split from Lampsils. This month, we can all turn our gaze to Hamiota subangulata — the June 2024 Mussel of the Month!

The species of Hamiota are distinctive for their “super-conglutinates,” which are used to attract the obligate hosts of their parasitic larvae. Various mussel taxa are known for the adaptive mimicry that has evolved to attract their host fishes. For example, Lampsils and related genera commonly have mantle lures that attract fish to come close enough to get a face-full of parasitic mussel larvae (known as glochidia). These larvae encyst in the fish’s gills and undergo metamorphosis. The life cycle of a freshwater mussel is shown to the right (Cummings & Graf, 2010). A cool photograph of a mantle lure is available on the FMCS website.

Other freshwater mussels package their glochidia in conglutinates: concentrated bundles of infectious larvae and mucus. These work like a Trojan Horse wherein the conglutinate is ingested by the host fish. However, instead of getting swallowed, the conglutinate releases its many larvae to infect the fish’s gills. In the case of the genus Ptychobranchus, conglutinates are made that much more enticing by looking like insect larvae. Check out this photo on the FMCS website.

In the case of mussels in the genus Hamiota, their super-conglutinates combine both strategies of fishing with a lure with a tempting package of infectious glochidia. Super-conglutinates, as their name suggests, are large conglutinates — one big one rather than many small conglutinates. That is cool enough, but there is more! Mussels like Hamiota subangulata dangle their flipping and flopping super-conglutinates from a gossamer line of mucus. Hamiota subangulata and its congeneric species go fishing for larval hosts with a lure and line.

Check out this cool video of Hamiota subangulata in action!