Trichosomaptera, Pham, Minhlan, Bai, Xiaoshuan, Heiss, Ernst & Cai, Wanzhi, 2014

Pham, Minhlan, Bai, Xiaoshuan, Heiss, Ernst & Cai, Wanzhi, 2014, Aradidae from Vietnam III. Trichosomaptera gibbosa n. gen., n. sp., an apterous Carventinae (Hemiptera: Heteroptera: Aradidae), Zootaxa 3768 (3), pp. 395-400 : 396

Trichosomaptera new genus Bai, Heiss & Cai

Type species: Trichosomaptera gibbosa n.sp.

Diagnosis. Resembling the apterous genus Dasyaptera Usinger & Matsuda 1959 but is distinguished from the latter by the stylate eyes (eyes not stylate), more slender and longer antennae about 1.36x as long as head (as long as head), a narrower head about 0.7x as wide as long (as wide as long), by mtg III strongly elevated medially into a subcylindrical pilose hump (without such hump), and by spiracles II ventral and not visible from above (all spiracles lateral and visible from above).

Description. Small-sized apterous. Body elongate oval, surface structures partially with dense pilosity, uncovered parts glabrous and shiny; elevated thoracic lobes and hump of mtg III beset with tufts of long stiff yellowish setae. Legs and antennal segment I beset with long curved setae.

Head. Distinctly longer than width across eyes; clypeus prominent, genae thin as long as clypeus; antenniferous lobes short and stout diverging anterolaterally with subacute apex; antennae about 1.9x as long as width of head across eyes, segment I longest with long stiff setae, these curved at apex, II shorter, III with a long petiole, IV shortest; eyes stylate; postocular lobes very long, converging posteriorly, lateral margin beset with stiff erect setae, these more dense on carinate vertex. Rostrum arising from a slit-like atrium, not reaching limits of rostral groove. Rostral groove deep and wide at base, open posteriorly.

Pronotum. Nearly 3x as wide as long; collar distinct; lateral lobes elevated and pilose, depression between them glabrous; posterior margin distinctly delimited by a deep transverse medially convex groove.

Meso- and metanotum. Fused at middle to each other and to mtg I+II, the mesonotal part of this median sclerite with 2(1+1) oval pilose ridges separated by a deep cleft followed posteriorly by a glabrous concave plate belonging to metanotum and mtg I+II; lateral lobes of metanotum raised and pilose, fused mtg I+II with tuft of setae lateral of median plate, lateral parts glabrous and sloping.

Abdomen. Tergal plate subrectangular consisting of fused mtg III–VI; mtg III strongly raised medially into a subcylindrical hump, its apex covered by long stiff setae; mtg IV–VI elevated medially into a smooth ridge, lateral parts glabrous; deltg I+II fused; deltg III–VII separated by sutures; lateral margins of deltg IV–VII with posteriorly increasing angular projections bearing spiracles IV–VII which are visible from above; mtg VII raised medially.

Venter. Spiracles II ventral, III–IV sublateral, V–VII lateral on distinct tubercles, all except II visible from above,VIII terminal on ptg VIII; pro,-meso, and metasternum fused to mst II+III forming a smooth glabrous polygonal plate; mst IV–VI smooth at middle, rugose laterally; sternite VII with a longitudinal smooth ridge medially and with 2(1+1) tubercles on either side; pygophore conical and constricted posteriorly, ptg VIII clavate.

Legs. Long and slender beset with erect setae; femora only feebly incrassate, trochanters fused to femora; tarsi short, claws with thin pulvilli.

Etymology. Referring to the conspicuous body structures, from>trichos<(Greek) hairy,>soma<(Greek) body and its apterous condition.

Distribution. Only one species from Vietnam is known to date.

Discussion. The presence of the striking dorsal hump on mtg with long yellowish tufts of setae is unique among the family Aradidae . This hump seems to be an obstacle when copulating and a disadvantage for the life in subcortical or leaf litter habitats where they occur. Thus its function remains unknown.