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Tiny Tiny Fungus Beetle - Malacocis brevicollis

Tiny Tiny Fungus Beetle - Malacocis brevicollis
Near Ruraldale, Upshur County, West Virginia, USA
February 15, 2006
Size: 1.7 mm
Probably my tiniest beetle photographed to date. A tripod set-up would have helped here, as well as some extra oomph to my macro lens.

I'm debating several families of small fungus beetles, but my best bet seems to be Minute Tree-Fungus Beetles. I'm posting three photos, possibly of different individuals, showing the species from different angles. One shows the antennae.


Very good photo!!!

It seems more like a "Malacocis brevicollis". "Ropalodontus americanus" has a more elongate body, elytra parallel-sided with coarser punctation (at least in the paratypes I analysed).

Comparing both genera, "Malacocis" has a smaller pronotum, more conspicuous antennal club, broader prosternal process, spines of protibiae restricted to their apices, and males bearing a circular and pubescent fovea in the first abdominal ventrite. "Ropalodontus" has the protibiae expanded and spines at their outer edges, laminate prosternal process, and abdominal fovea in males with a flap cover.

I'm using the spelling "Ropalodontus" instead of "Rhopalodontus" according to a recent article of a british colleague.

cf. Rhopalodontus americanus
key characters invisible, but: very short body, strong elytral punctures and bristly elytral pubescence strongly indicate genus Rhopalodontus, with only one N-Am. species according to Nearctica.

regards, Boris

Boris, Thanks for the ID help with this tiny beetle.