Gorhamium gen. nov.

Type species.

Gorhamium bidentatum sp. nov. (by present designation).

Diagnosis.

Gorhamium gen. nov. can be distinguished from other Eurrhacini by the combination of the following characters: a) elytra (Fig. 2 A – C) with nine longitudinal costae (4 costae in Haplobothris); b) pronotum (Fig. 3 A, B) wider than long (elongated in Calocladon); c) median areola on pronotum slenderly lenticular (slightly wider in Cladocalon and Atlanticolycus); d) male antennomere 3–10 flabellate (Fig. 4 B, C); e) aedeagus with each paramere projected ventrobasally into a slender, medially curved process (d 1, Fig. 6 C), sometimes joining at midline forming an annular bridge (d 3, Fig. 6 G) (also present in Calocladon, Cladocalon, and Atlanticolycus). Among unique features of Gorhamium gen. nov. belong: a) base of phallus pointed anchored-shaped (inverted mushroom-shaped), with arcuate arms and a pointed tip (a 1, Fig. 6 E, F), while the base of phallus of Cladocalon and Atlanticolycus is flat, or rounded (a 2, Fig. 6 A); b) median portion of phallus extending ventrally into oval opening (b, Fig. 6 C); c) dorsal edge of phallus hooked (c, Fig. 6 D, G); d) internal sac membranous with minute spines distally (e, Fig. 6 D, G); e) parameres shorter than 2 / 3 of phallus (while the parameres are almost as long as phallus in Atlanticolycus); f) base of parameres semicircular in cross-section (flattened / ribbon-like in Cladocalon); g) apex of parameres denticulate, provided with one or two coarse teeth; h) female genitalia with valvifers as long as coxites and styli combined (Fig. 6 H).

Description.

Body length: 5.5–6.4 mm, width across the humeri: 1.2 mm. Head partly covered by pronotum from above. Labrum small, mandibles slender, arcuate (Fig. 4 A). Maxillary palps 4 - segmented, gradually widened distally, palpomere 1 (= P 1) at least 3 × shorter than P 2, P 2 longest of all, ~ 2 × longer than P 4, P 3 1.5 × shorter than P 4, terminal palpomere securiform, apex obliquely rounded (Fig. 4 A). Terminal palpomere of labial palps securiform. Pronotum somewhat trapezoidal, with anterior margin produced forward, posterior margin 1.4 × wider than median length; lateral margins divergent posterad, with anterior 2 / 3 almost straight, convergent anteriorly, posterior angles acute; posterior margin bisinuate, medioposterior process almost triangular (Fig. 3 A, B); median longitudinal carina on pronotum bifurcating in anterior third, forming very slender, lenticular areola. Scutellum square, apex minutely emarginate medially (Fig. 3 A). Elytra subparallel-sided, slender, 4 × longer than humeral width (Fig. 2 A – C). Each elytron with nine longitudinal costae (4 primary costae and 5 less elevated secondary costae), primary costae 2 and 4 strongly elevated; intercostal intervals with a row of irregular reticulate cells, secondary costae 3 and 4 absent posteriorly. Anterior thoracic spiracles small, tubulate. Legs compressed, trochanters almost triangular (Fig. 4 A), as long as third of femur, tibiae straight, their spurs small, covered by pubescence, tarsomeres 1–4 lobed.

Male. Eyes medium-sized to large, eye diameter 1.3–1.7 × longer than interocular distance. Antennae reaching beyond elytral midlength, antennomeres 3–10 flabellate, antennal branches flattened, antennomere 1 (= A 1) stout, A 2 small, transverse, A 3 slightly (1.15–1.3 ×) shorter than A 4, A 4 – A 10 subequal in length. Lamellae arise basally, lamella of A 3 slightly longer than antennomere body, remaining lamellae considerably longer. Abdominal sternum VIII widely emarginated distally (Fig. 5 C, F), emargination shallow, as deep as ¼ of sternum length. Sternum IX elongate, 3.5 × longer than wide (Fig. 5 A, E), widest in distal quarter, proximal half narrow with lateral margins convergent. Phallus with ventromedial oval opening (b, Fig. 6 C, G), base of phallus pointed anchored-shaped, or inverted mushroom-shaped (a 1, Fig. 6 E, F); distal portion of phallus rod-like, apex clavate, dorsal margin hooked (c, Fig. 6 D, G); internal sac membranous with minute spines distally (e, Fig. 6 G), sometimes also medially. Parameres at most as long as 2 / 3 of phallus, base of parameres almost semicircular in cross-section; each paramere projected basally in a thin ventral, medially arched, process (d 1, Fig. 6 C), sometimes joining medially in a ring-like bridge (d 3, Fig. 6 G); parameral apex denticulate, provided with one or two coarse teeth. Phallobase slightly asymmetrical, distorted, moderately arched ventrally.

Female. Eyes small, interocular distance 1.3 × longer than eye diameter, antennae serrate (Fig. 2 B). Terminal sternum (IX) simple (Fig. 5 D), spiculum gastrale rudimentary, triangular. Ovipositor with valvifers 1.3 × longer than coxites (Fig. 6 H).

Etymology.

The genus is named in honor of H. S. Gorham, the author of chapters on Malacodermata in Biologia-Centrali Americana (Gorham 1880, 1881, 1884), where he described many genera and species of Eurrhacini and Calopterini . The gender is neuter.

Distribution.

Panama, Ecuador.