Georissus

Georissus
G. laesicollis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Coleoptera
Suborder:	Polyphaga
Superfamily:	Hydrophiloidea
Family:	Georissidae Laporte, 1819
Genus:	Georissus Latreille, 1809

Georissus, also called minute mud-loving beetles, is the only genus in the beetle family Georissidae (or Georyssidae). They are tiny insects living in wet soil, often near water. Found on every continent except Antarctica.

Characteristics

Georissidae are small beetles (length 1–2 mm). They have a broadly oval body whose outline is more or less interrupted between the pronotum and the elytra. The head and pronotum are granulate, the prosternum is rudimentary, without intercoxal processes. The anterior coxae and trochanters are fused. The basal ventrite is very large.

Systematics and evolution

There are about 75 living species, including:

• Georissus australis
• Georissus babai
• Georissus bipartitus
• Georissus caelatus
• Georissus californicus
• Georissus canalifer
• Georissus capitatus
• Georissus coelosternus
• Georissus costatus
• Georissus crenulatus
• Georissus formosanus
• Georissus fusicornis
• Georissus granulosus
• Georissus instabilis
• Georissus japonicus
• Georissus kingii
• Georissus kurosawai
• Georissus laesicollis
• Georissus minusculus
• Georissus occidentalis
• Georissus pusillus
• Georissus sakaii
• Georissus septemcostatus
• Georissus substriatus
• Georissus trifossulatus

The genus is divided into three subgenera (Georissus, Neogeorissus and Nipponogeorissus). Formerly it was included within the family Hydrophilidae. Recent molecular data indicate, that they belong to a clade comprising the small groups of Hydrophiloidea - Epimetopidae, Hydrochidae, Helophoridae and Georissidae.