Margarinotus, MARSEUL, 1853

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 : 2

MARGARINOTUS MARSEUL, 1853

Diagnosis. Among Histerini , Margarinotus are generally recognizable by the presence of a complete outer subhumeral elytral stria. Most species have multidenticulate, rounded protibiae, with only poorly developed marginal teeth, with the protibia shallowly excavate between the teeth on the anterior surface. However, they are most unambiguously diagnosed by their distinctive aedeagus, with an elongate median lobe with articulated dorsal armature that rotates upwards when extruded ( Figs. 2 , 4 , 5 , 8 , 10 ). In California, they are the most common all-black Histerini , and the most common Histerini in general (though that is not to say that they are common – they are rarely encountered). Of the five species of true Hister known to occur in California, none have a complete outer subhumeral stria, and only Hister militaris Horn is fairly widespread, with Hister abbreviatus F. extending barely into the northern part of the state, and Hister comes Lewis and Hister coenosus Erichson extending into the more monsoonal-influenced extreme southeastern part of the state. Two species of Spilodiscus Lewis occurring in California exhibit red elytral maculations. The adventive Margarinotus obscurus (Kugelann) has not yet been recorded in California, but is known from Washington and Oregon, and may occur in northern California. This species has an abbreviated outer subhumeral elytral stria, and can only be assigned to the genus on the basis of genitalic and protibial characters.

Figures

Fig. 2. Margarinotus ephemeralis and Margarinotus remotus, median lobe of aedeagus. A. M. ephemeralis, dorsal view.B.M. ephemeralis, lateral view.C. M. ephemeralis, apical view of gonopore. D. M. remotus, apical view of gonopore. E. M. remotus, dorsal view. F. M. remotus, lateral view.

Fig. 4. Margarinotus spp., median lobe of aedeagus. A. M. fractifrons, dorsal view. B. M. fractifrons, lateral view. C. M. harrisii, dorsal view. D. M. harrisii, lateral view. E. M. rectus, dorsal view. F. M. rectus, lateral view. G. M. pluto, dorsal view. H. M. pluto, lateral view.

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. 8. Margarinotus thomomysi, median lobe of aedeagus. A. Dorsal view. B. Lateral view. C. Apical view of gonopore.

Fig. 10. Margarinotus sexstriatus and Margarinotus merdarius, median lobe of aedeagus. A. M. sexstriatus, dorsal view. B. M. sexstriatus, lateral view. C. M. merdarius, apical view of gonopore. D. M. merdarius, dorsal view. E. M. merdarius, lateral view.