Hymenorus Mulsant, 1851

Campbell, J. M., 2014, An unusual suite of sexual characters in three new species of Hymenorus (Coleoptera, Tenebrionidae, Alleculinae) from Guatemala and Mexico, ZooKeys 415, pp. 295-309 : 296

Hymenorus Mulsant, 1851

Hymenophorus Mulsant, 1851, p. 201 [1852a, p. 68]; type species Hymenophorus doublieri Mulsant, 1851, by monotypy. Novák 2006, p. 317; Novák 2007; Novák and Petterrsson 2008, p. 322.

Hymenorus Mulsant, 1852, p. 188 [emendation]; Mulsant (1856a: 17, 33); Jacquelin du Val (1861: 344, 356); LeConte (1866: 137); LeConte and Horn (1883: 390); Champion (1888: 386, 424); Seidlitz (1896: 49); Casey (1891: 72, 83); Blatchley (1910: 1271, 1273); Reitter (1911: 351, 352); Fall (1931: 161); Chagnon and Robert (1962: 325); Campbell (1962:9 2); Arnett (1962: 703); Hatch (1965: 183); Campbell (1971: 68); Campbell (1982: 31; Campbell (1984: 296); Downie and Arnett (1996: 1099); Aalbu et al. (2002, 480, 499); Steiner (2004: 739); Althoff et al. (2005: 905); Bouyon (2011: 191); Kanda (2013: 587).

Description.

A full description of the New World species of Hymenorus is not possible at this time pending modern revisions of the more than 170 North and Central American species of the genus. However, the following brief description will readily distinguish these three species from all other New World species of Hymenorus .

Body narrowly elongate-oval (Fig. 1); length 7.5-10.0 mm. Eyes large, moderately separated dorsally; OI of males varying from 18 to 27, females slightly more widely separated, OI varying from 18-33. Antennae narrowly elongate, antennomeres four through ten narrowly elongate, approximately two times longer than wide. Pronotum (Fig. 2) wider than long, width at base slightly narrower than width of base of elytra; PI ranging from 62 to 78; disc with fine, dense microsculpture between punctures; punctures coarse, dense, narrowly separated, evenly distributed over disc; each puncture obliquely impressed. Metaventrite moderately densely punctate medially, punctures becoming sparser laterally; without median patches of dense, elongate setae. Like all Hymenorus species, the third and fourth segments of the pro- and mesotarsi and the penultimate segment of the metatarsi have a distinct membranous lobe on the ventral margins.

Male. Hymenorus excavatus and Hymenorus bifurcatus have the second segment of the anterior tarsus with a small, rudimentary lobe and a densely pubescent pad on the venter of the basal segment; only the third and fourth segments of the protarsi are lobed in Hymenorus balli . The anterior tarsal claws of the three species each have at least 20 teeth (Fig. 3). The fifth abdominal ventrite is highly modified, in one species ( Hymenorus excavatus ) (Figs 10, 11), the ventrite is deeply, triangularly excavate from the apical margin to the anterior third; in Hymenorus balli (Figs 4-5) and Hymenorus bifurcatus (Figs 7-8) the ventrites have a distinct, bifurcate process projecting ventrally from the middle of the disc. Lobes of eighth sternite of each species are highly modified (Figs 19-21), unlike any other species of the genus.

Female. The ninth tergite (Figs 6, 9, 12) of each species is highly modified and completely unlike any other known species of the genus. In most species of the genus the apical margin of the tergite is evenly convex and the length of the tergite varies from short to elongate.

Remarks.

I have not provided a key to distinguish these species. Other than sexual characters they are very similar. The modifications of the male fifth abdominal ventrite and lobes of the eighth sternite and the shape of the female ninth tergite will readily distinguish the species. In most series a few of the sexual characters are readily visible without dissections.