Amamiclytus Ohbayashi, 1964

Niisato, Tatsuya & Han, Chang-do, 2011, A revision of the genus Amamiclytus Ohbayashi from Taiwan and the Ryukyu Islands (Coleoptera, Cerambycidae), ZooKeys 118, pp. 19-52 : 21-25

Genus Amamiclytus Ohbayashi, 1964

Amamiclytus Ohbayashi 1964: 21, pl. 4, fig. 1; type species: Amamiclytus nobuoi Ohbayashi, 1964.

Description.

Small to very small clytine with black, glossy body arranged with white pubescent maculations on pronotum, elytra and ventral surface, characterized by relatively well-separated eyes, and dense hair on middle and hind tibiae. Colour mostly black, glossy, sometimes more or less matted, usually with brownish antennae and legs, and sometimes also on meso- and metathoraces, and abdomen. Hairs and pubescence mostly very short though some partially dense and long; head usually sparsely clothed with pale gray pubescence on frons in both sexes, though more or less sparsely so in ♀; antennae with long, pale brown hairs along underside of 2nd to 4th or 5th segments; pronotum thinly pubescent, with white pubescent band along base (Pb), transverse or separated at sides, though sometimes sparse or quite absent according to species; scutellum with fine pale pubescence; elytra basically with three white maculations: 1) semicircular maculation or slightly oblique short band on basal third to fourth (La), 2) almost complete arcuate band on apical third to 2/5 (Lp), 3) narrow but usually clear band at apices (A), supplemented with the following maculation according to species: 4) basal narrow band (B), 5) sutural spot behind scutellum (S); prosternum with white pubescence on basal half to 2/3; metasternum with white pubescence at sides (Msl) and on intercoxal process (Mss); metathorax with L-shaped band along apical margin of metasternum, extending to apical half to 2/3 of metepisternum (Mta); abdomen with white pubescence at sides of ventrites 1-2, sometimes with same, though sparse maculation on ventrite 3 or ventrites 3-4 (V1-V4).

Head across eyes almost equal to the width of pronotum; frons almost quadrate, flattened, provided with a fine smooth median line, usually closely or coarselypunctured; clypeus flattened or slightly raised; mandible short and broad, rather strongly hooked near apex, with almost smooth inner margin, covered with numerous short hairs on surface, a few long hairs on outer margin near apex; maxilla with galea and lacinia weakly developed, terminal segment of palpus clearly flabellate, strongly dilated apicad in ♂, weakly so in ♀; terminal segment of labial palpus strongly dilated apicad in ♂, weakly so in ♀; vertex raised towards antennal cavities which are usually separated each other by half to 2/5 the width of occiput; occiput distinctly convex; genae relatively shallow, almost half to 1/3 the depth of lower eye-lobes in frontal view; eye moderately large, almost semicircular, a little narrower than frons in frontal view. Antennae thin, moderate in length or relatively long, slightly thickened apicad except for those of Amamiclytus hirtipes which are simply slender; scape almost cylindrical, 3rd segment 1.5-2.0 times as long as 4th segment, terminal segment usually obtusely pointed.

Pronotum globose or slightly elongate, slightly narrower than elytra, simply arcuate at sides; disc distinctly convex though slightly depressed above, provided with large shallow punctures. Scutellum small, regular triangular.

Elytra relatively short to relatively long; sides rounded at humeri, weakly arcuately emarginate at a level between basal fourth and apical half; apices oblique, slightly arcuate at margins, usually with weak dents at external angles; disc evenly convex with slight depression near suture just behind scutellum. Hind wing with vein Cu not attaining AA3+4 which is forming an ordinary H-shape.

Ventral surface smooth; prosternum moderately emarginate near apical half in profile; metasternum slightly convex; abdomen relatively slender, with male anal ventrite arcuately rounded at apical margin.

Legs long and slender; hind legs 1.5-2.0 times as long as elytra, with femur gradually swollen apicad, slightly compressed, usually exceeding elytral apex at apical fifth, almost equal to the length of hind tibia, 1st tarsal segment varied in length according to species, 1.5-2.5 times as long as the following two segments combined.

Male genitalia. Relatively large and somewhat elongate, basically related to that of several species of Rhaphuma . Median lobe elongate and slender, slightly reflexed in profile; dorsal plate almost equal in width to, or a little longer than ventral plate, gently narrowed to rounded apex; ventral plate gently narrowed to pointed apex; median struts slender. Endophallus about twice the length of median lobe, provided with minute or medium-sized spinous spicules behind crescent-like sclerites, densely cov ered with minute serrate or crenulate spicules on apical part. Tegmen usually elongate, shorter than median lobe; parameres nearly half to 2/5 the length of tegmen, divided in apical fifth to third, with each lobe almost rounded at apex, which is provided with short and long setae; basal ridge raised. Eighth tergite more or less elongate, slightly longer than wide. Eighth sternite distinctly transverse, emarginate or transversely truncate at apical margin, provided with long projection at middle of basal margin.

Female genitalia. Coxite lobe ovoid, scattered with short and long setae. Stylus half to equal in length to coxite lobe, elongate, weakly dilated apicad. Spermatheca narrow, weakly broadened apicad; gland short and thin; duct relatively long and thin.

Geographical distribution.

Indochina, China, Taiwan, Japan (Ryukyus), Malay Peninsula, Sumatra and Borneo.

Comments.

The species of the genus Amamiclytus Ohbayashi have so far been known from a rather restricted area between Indochina and the Ryukyu Islands of Southwest Japan. However, several undetermined species belonging to the genus have been found from Sumatra, Borneo and the Malay Peninsula. The genus contains small, glossy black species with pure white pubescent maculations on the body surface, and are slightly similar in external appearance to several members of the genus Rhaphuma Pascoe. They share the following features: 1) body relatively elongate, especially in elytra, meso- and metasterna, and legs; 2) antennae thin and long, with 3rd segment usually longer than scape; 3) antennal cavities approximate each other; 3) eyes large and prominent, rather distinctly approximate in front; 4) mandible almost smooth and provided with numerous short hairs along inner margin; 5) labial and maxillary palpi show distinct sexual dimorphism in each terminal segment, strongly dilated apicad in ♂ or weakly so in ♀. However, Amamiclytus is very distinct in the tribe Clytini by a combination of the following characters: 1) body small and rather convex, with relatively long antennae and legs; 2) colour wholly black, usually brownish antennae and legs, strongly glossy or sometimes more or less matted; 3) white scaly pubescence form the maculations on elytra, ventral surface and sometimes on the base of pronotum, of which elytra are always provided with three arcuate or transverse bands, sometimes supplemented with vague basal band along basal margin and a longitudinal spot near suture behind scutellum; 4) mid and hind tibiae provided with long erect hairs; 5) frons relatively wide, with a fine median groove; antennae usually thickened towards apical segments, though simply slender in Amamiclytus hirtipes , with antennal cavities widely separated at sides of frons; 6) pronotum rather convex, simply arcuate at sides; 7) male genitalia relatively large, with endophallus densely provided with minute serrate or crenulate spicules on apical part, without spinous spicules.

Adults of the genus are usually found on various types of tree blossoms as Castanopsis , Quercus and Acer mainly in spring and early summer season, such as February to June, except for Amamiclytus hirtipes which appears in the autumn season. Larvae of Amamiclytus nobuoi , bore in the dead, thin twigs of Machilus thunbergii and Rhaphiolepis indica var. umbellata (Niisato, 2007).

Key to species of the genus Amamiclytus from Taiwan and the Ryukyu Islands