With over 300 species, California is home to a great diversity of darkling beetles. Members of this family are common everywhere, but especially in drier areas. Flightless 'stink beetles' in the genus Eleodes are conspicuous in a variety of habitats throughout the state. But while these large, slow beetles exemplify the family in some ways, many Californian darkling beetles look nothing like these.

Coal Oil Point is home to at least 7 species of darkling beetles, including several coastal specialists. The small, ladybird-like Phaleria rotundata is found only in sandy coastal areas, as are Epantius obscurus and two species in the genus Coelus. One of these, the Globose Dune beetle (Coelus globosus) has become rare throughout its range, and is a state 'species of concern'. The two species of Coelus are difficult to tell apart, but C. globosus is usually slightly larger, and has the 'clypeus' (a part of the head above the mouth) more deeply cut-out, as shown in the picture below. The dune beetles leave a distinct track on the beach that resembles a labyrinth. Their footprints cannot be seen on the track because the beetle walks below the sand, leaving a collapsed tunnel behind.

Tenebrionid Photos (click to enlarge)
Coelus ciliatus	clypeus, C. ciliatus	clypeus, C. globosus
Phaleria rotundata	Epantius obscurus