Schistomerus is an extinct genus of predaceous diving beetle that is known from one species, Schistomerus californense, which inhabited Lake Barstow during the middle Miocene.[1] It is the most common beetle found in the concretions from the Barstow Formation. The specimens are typically preserved in three dimensions.

Temporal range: Middle Miocene, 13.4 Ma
Scientific classification edit
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Dytiscidae
Genus: Schistomerus
S. californense
Binomial name
Schistomerus californense
(Palmer, 1957)

All ontogenetic stages of the beetle are present in the concretions. The larval stages of the beetle are most commonly represented, and the mature larvae range from 4.5 - 5.5 mm long.[2] Only 3 adults have been recovered.

Due to the preservational conditions of the formation, a number of individuals were preserved with intact internal anatomy. The tracheal system as well as parts of the organism's nervous system have been described.[2]

See alsoEdit


  1. ^ Park, Lisa E.; Downing, Kevin F. (April 2001), "Paleoecology of an Exceptionally Preserved Arthropod Fauna from Lake Deposits of the Miocene Barstow Formation, Southern California, U.S.A", Palaios, Society for Sedimentary Geology, 16 (2): 175–184, doi:10.1669/0883-1351(2001)016<0175:POAEPA>2.0.CO;2, ISSN 0883-1351
  2. ^ a b Palmer, A.R., 1957, Miocene arthropods from the Mojave Desert California: U.S. Geological Survey Professional Paper, v. 294-G, p. 237-280.