Glaresidae, Kolbe, 1905

Gordon, Robert D. & Hanley, Guy A., 2014, Systematic revision of American Glaresidae (Coleoptera: Scarabaeoidea), Insecta Mundi 2014 (333), pp. 1-91 : 4

Family Glaresidae

Glaresidae Kolbe 1905: 543 (as Glaresini ); Semenov-Tian-Shanskii and Medvedev 1932: 22 (as Glaresini : Troginae ); Scholtz 1987: 353 (as Glaresidae , stat. n.); Jameson 2002: 15; Král and Löbl 2006: 81.

Description. Length 2.5-6.0 mm. Color light tan to dark brown. Head deflexed; antenna 10-segmented, club 3-segmented, basal segment largest, usually cupuliform and partially enclosing segment 2; eye divided by large canthus, dorsal portion of eye small, ventral portion large; mandibles heavily sclerotized, molar region varies from having 3 blunt teeth to having a plate-like surface, apex may be asymmetrically dentate with more teeth on one mandible than the other. Elytra with 8-10 costae (all American species have 10 costae). Thorax long, with well developed wings, metasternum may have deep metasternal groove for reception of mesotarsus. Metipemeron with apical projection extended over lateral elytral margin, locking elytron in place. Protibia strongly developed for digging with 3 teeth; meso - and metatibia armed with dentiform processes and various ridges and setae; metatibia broad, spatulate, metatafemora and metatibia enlarged to cover abdomen in retracted position. Abdomen with 5 visible ventrites. Male genitalia simple, symmetrical, trilobed, with parameres and median lobe fused to basal piece which is either shorter or longer than parameres.

Remarks. The family description above is modified after Scholtz (1987), who was first to positively place the genus Glaresis in a family of its own based on various characters. Scholtz et al. (1994) confirmed that family assignment based on phylogenetic assessment of 72 characters such as eye structure, wing venation, etc.

Most Glaresis species, except for the distinctive G. pardoalcaidei , are apparently not sexually dimorphic, but G. phoenicis , G. dakotensis , and G. medialis have modified apices of the 5th abdominal ventrite, and some species of the mendica group also have similar modifications. Males may usually be recognized in spite of lack of secondary sexual differences because the abdominal apex is often curled ventrally, or at least straight. In females the abdominal apex is usually curled or angled dorsally. In most Coleoptera species the abdomen is a firm, well sclerotized structure capable of protecting the apical ventral surface. In Glaresis this protective function is taken over by the expanded metafemur and metatatiba resulting in an abdomen that has a soft, flexible, lightly sclerotized structure.

Species of Glaresis are known from all major regions of the world except Australia (also none from Chile). The Afrotropical region has 18 species; Palearctic Region, 23 species (including those from North Africa); Madagascar, 1 species; Nearctic Region, 25 species; and Neotropical Region, 7 species.