Rock Pools

Here is a new species of Berosus from Venezuela that will appear in a forthcoming paper. It has a very specific habitat: it lives in "pothole" pools in the large granite outcrops in the Guiana Shield region. Despite our sampling efforts, this species has only been found in these pools, where it can be fairly common--but nowhere else...not even in nearby forest pools or ditches! Another example of the high habitat specificity in the region.

UAE Hydrophilids

Ever want to identify your water scavenger beetles from the United Arab Emirates, but frustrated by lack of a good key? No more! See the latest volume of the "Arthropods of the UAE" for the complete reference.

The Giant Water Scavengers

After unnecessary dawdling, my work on the Hydrophilina was finally published this month in the journal Systematics and Biodiversity. In addition to the first phylogeny for the group, a very curious new genus is described from Venezuela:

Short, A.E.Z. 2010. Phylogeny, evolution and classification of the giant water scavenger beetles (Coleoptera: Hydrophilidae: Hydrophilini: Hydrophilina). Systematics & Biodiversity, 8(1), 17-37.

Abstract. The hydrophiline subtribe Hydrophilina is composed of nearly 200 described species, including all known water scavenger beetles over 15 mm in length. Found in all biogeographic regions, the lineage is the most recognizable group in the family due to its large size and presence of a sternal keel. A phylogenetic analysis of Hydrophilina based on 80 adult morphological characters supports the reciprocal monophyly of most genera, including Tropisternus Solier, Sternolophus Solier, Hydrophilus Geoffroy, and Hydrobiomorpha (s. str.) Blackburn. The monophyly of Hydrochara Berthold was not resolved. The subgenus Brownephilus Mouchamps of the genus Hydrobiomorpha is elevated to generic rank and suggested to subtend (Hydrophilus+ Hydrobiomorpha (s. str.)). A newly discovered taxon from Venezuela, Protistolophus spangleri gen. et sp. nov., is described and resolved as the earliest diverging lineage of the Hydrophilina. A revised generic classification of the Hydrophilina is proposed, including a key and revised diagnoses for each genus. The evolution of giantism and complex secondary sexual characters are discussed in the context of the newly developed phylogenetic hypothesis.

More Oocyclus

I spent some time over the last few weeks playing with our imaging system here in the division. I'm still learning, but so far I'm pleased with the results. Here is a composite of some of the new Oocyclus from Venezuela I am describing with Mauricio Garcia. I've just finished the photos for all 15 species. Next up: tackling the 35+ species of Berosus. The time it takes to take the actual photos is not really that long (I take as stack of about 15-25 images and then use CombineZ to smash them together)--the tedius time-involved process is selected a presentable specimen that is CLEAN (or, as clean as you can get it) and positioning it just so.

Side Project: Spangler's Tropisternus

Once upon a time Paul Spangler, Godfather of Neotropical Waterbeetleology and curator of Coleoptera at the Smithsonian compiled perhaps the most exhaustive treatment of a water scavenger beetle group ever written: a 1000+ page tome on the genus Tropisternus. It is a beast (see photo of the binders that collectively hold just about every piece of information known on this common group). Sadly, after 40 years in the making and 70,000 specimens it never quite crossed the finish line that is "publication" before his retirement. Having borrowed the raw drafts and disks from the Smithsonian, I have been working on and off (mostly off) for the last two years trying to coax/shove it across that finish line. I've recently started making a more concerted effort to get it done. This group is one of the most commonly encountered water beetles in the Americas, and deserves its do, as does Paul. Stay tuned!

Species of the Month: June

Our very first species of the month is a new species of water scavenger beetle in the genus Oocyclus. It doesn’t have a name yet, so feel free to suggest one! This little iridescent green sphere lives in rock seeps and the spray zones of waterfalls in the Venezuelan Andes (in this case, near Trujillo). I’ll take this opportunity to note the blog title refers to the lab’s research interest in insects that live in these kinds of habitats. So far, our work in Venezuela has found 15 new species in this genus. Based on this and preliminary data from elsewhere, it would not be surprising if northern South America was home to 50 or more species. These guys tend to be relatively localized to regional mountain chains, with 2 to 4 species endemic to each chain. I don't have a good up-close habitus photo yet. I'll post one when I do; they look cooler in their element anyway.