Bostrichoclerus Van Dyke, 1938

Burke, Alan & Zolnerowich, Gregory, 2017, A taxonomic revision of the subfamily Tillinae Leach sensu lato (Coleoptera, Cleridae) in the New World, ZooKeys 719, pp. 75-157 : 97-98

Bostrichoclerus Van Dyke, 1938

Type species.

Bostrichoclerus bicornis Van Dyke, 1938, original designation (monotypy).

Distribution.

Shown in Fig. 21E.

Type locality.

Palm Cañon, Angel de la Guardia, Golf of California, Mexico. Type depository: California Academy of Sciences (CASC).

Distribution.

USA: CA; Mexico: Baja California.

Due to the rarity of the species, this unusual clerid was not examined in this revisionary work; however, in order to complement the revision of the Tillinae in the New World, the descriptive work of Van Dyke (1938) is given here.

Differential diagnosis. The species is most similar to Cymatodera . It, however, does not look like any species of the latter genus, but at first sight rather like a large species of the genus Polycaon of the family Bostrichidae , also because of its size and general appearance somewhat suggests Natalis [ Cleridae : Clerinae ]. Its distinctive peculiarities are the prominent horns, the type of antennae and the glabrous elytra.

Description. Large, elongate, very finely and sparsely pilose. Head large; eyes large, transverse, coarsely granular, feebly emarginate in front, and very prominent; antennae long, 11 segmented, scape robust, segments 2-5 about twice as long as broad, feebly clavate and quite glabrous, a few stiff hairs only being evident, segments 6-10 moderately serrate, eleventh fusiform, the free angles of 6-8 densely clothed with fine silky pile and the three following segments completely clothed; a prominent horn, laterally compressed and bifid at apex, arising from in front of each eye and just within the insertion antennae giving the latter the appearance of arising from their base; mandibles robust; maxillary palpi four segmented, labial palpi three segmented, the terminal segments of both sets securiform, that of the labial palpi the larger, and almost an equilateral triangle. Prothorax robust, somewhat longer than broad, broadly constricted at sides in front of middle and narrowed posteriorly, basal margin a complete and well defined bead; coxal cavities rounded and narrowly opened behind. Elytra almost 3 × as broad as prothorax, two and a half times as long as broad. Finely, densely and irregularly punctured and without striae except for fine sutural striae close to the suture and extending from about the middle almost to the apex. Anterior coxae conical, very narrowly separated, trochantine not visible; middle coxae somewhat conical well separated and with evident trochantine; hind coxae transverse. Abdomen with five free ventral segments. Legs long and slender; tibiae with short terminal spurs; tarsal segments all well developed, flattened dorsally, 1-4 broad yet longer than broad, with usual membranous appendages and densely papillose beneath, the fifth with sides somewhat papillose; claws simple.

Bostrichoclerus bicornis Van Dyke, 1938.

Description. Holotype: unique from Palm Cañon, Angel de La Guardia Island, Gulf of California, collected May 3, 1921, by J. C. Chamberlin, from beneath bark. Moderately large, dark brown and somewhat shining. Head flattened in front, densely punctured above, smooth and sparsely punctured anteriorly, with a faint medial, longitudinal impression on front and sparsely pilose. Prothorax about a sixth longer than broad, base lobed at middle and sinuate each side, apex broadly arcuate and overhanging, disk irregularly punctured, more closely and deeply so in front and with short, reclinate hairs widely scattered about, and broadly and feebly impressed at middle. Scutellum semicircular, densely punctured, rugose and concave. Elytra convex, with pronounced though well rounded humeri, sides almost parallel and disc somewhat dull as the result of the dense punctations and fine rugoseness. Beneath somewhat shining, densely punctured anteriorly and sparely behind. Legs with apices of tibiae beneath and undersurfaces of the tarsal segments from 1-4 densely clothed with short, silky, orange pile. Length 20 mm. with head flexed, breadth 6.5 mm.

Remarks.

Bostrichoclerus is remarkably different from other tillinid species in the New World. Van Dyke (1938) indicated that, based on the coarsely faceted structure of the eyes, the genus should be placed within Tillinae . He thought Bostrichoclerus was closely related to Cymatodera , but Bostrichoclerus is very different from all known forms of Cymatodera . According to Van Dyke, Bostrichoclerus bicornis is easily identified based on the prominent frontal horns, the shape of the antennae, and the completely glabrous elytral disc. Bostrichoclerus bicornis was described based on single specimen collected in Isla Angel de la Guardia in the Golf of California, Baja California, Mexico. Later on, a second specimen was collected in southern California ( Barr 1957). Material of this species has not been collected since.