Margarinotus (Ptomister) umbrosus (Casey, 1893)

Caterino, Michael S., 2010, A Review of California Margarinotus Marseul (Coleoptera: Histeridae: Histerinae: Histerini), with Descriptions of Two New Species, The Coleopterists Bulletin 64 (1), pp. 1-12 : 8

Margarinotus (Ptomister) umbrosus (Casey, 1893) ( Figs. 5E–G , 6 )

Hister umbrosus Casey 1893: 547 .

Hister umbratilis Casey 1916: 217 ; Wenzel 1960: 459. Synonym.

Margarinotus umbrosus (Casey) ; Wenzel 1944: 126.

Diagnosis. PEL= 3.43–4.86 mm; PNW= 2.62– 4.30 mm. See diagnosis under M. umbilicatus for a diagnosis of this species. In more northern populations assigned to this species, especially in British Columbia, the lateral apical teeth of the median lobe tend to be much reduced, almost disappearing to leave a single median tooth in many individuals. In California populations the lateral teeth are usually well developed, though smaller than the median one.

Remarks. Margarinotus umbrosus seems to be a more generalist species than its close relatives, having been recorded from dung, carrion, and decaying vegetation.

Distribution ( Fig. 6 ). This species occurs along the Pacific coast from central California (Marin Co.) through British Columbia ranging eastward in the north to Montana and Alberta.

Figures

Fig. 5. Margarinotus umbilicatus and Margarinotus umbrosus, median lobe of aedeagus. A. M. umbilicatus, dorsal view. B. M. umbilicatus, lateral view. C. M. umbilicatus, apical view of gonopore (variant). D. M. umbilicatus (typical form), apical view of gonopore. E. M. umbrosus, apical view of gonopore. F. M. umbrosus, dorsal view. G. M. umbrosus, lateral view.

Fig. 6. Map of known California localities for Margarinotus spp.