Pachytylaradus, HEISS, 2022

HEISS, ERNST, 2022, Pachytylaradus cretaceous gen. et sp. nov. from Burmese amber (Heteroptera, Aradidae), Palaeoentomology 5 (4), pp. 294-297 : 294-295

Genus Pachytylaradus gen. nov.

Type species. Pachytylaradus cretaceous sp. nov.

Etymology. Refers to the unusual large and wide tylus (clypeus), from ‘pachys’ (Greek) thick, wide and the relationship to Aradidae .

Diagnosis. Distinguished from all Aradidae described so far from Burmese amber by a combination of characters which was never observed together in other genera: large size; clypeus large and wide; antennae shorter than width of head; semicircular scutellum without median carina; no metathoracic scent glands; deltg II-VII without lateral expansions; hyaline membrane of hemelytra; surface of body densely beset with fine setigerous tubercles; claws with long pulvilli.

Description. Macropterous, large body size 6.9 mm; body flat, surface covered with short setigerous tubercles, which are larger and more dense on lateral margins of head, antennae, pronotum, scutellum, deltg II-VII and legs; coloration reddish brown.

Head. Wider than long, tylus (clypeus) large and expanded anteriorly, antenniferous lobes long and acute with dentate lateral margins; antennae shorter than width of head, segments I-III of about equal length, segment IV longest; Eyes slightly stalked, postocular lobes straight, not exceeding outer margin of eyes; vertex and tylus flat.

Pronotum. Strongly transverse, lateral margins sinuately converging anteriorly; disk flat with a shallow median depression; anterior and posterior margins concave.

Scutellum. Of semicircular shape, wider than long; surface flat without carinae.

Hemelytra. Corium about as long as scutellum, clavus distinct; membrane hyaline with distinct veins.

Legs. Unarmed. Femora distinctly thickened, tibiae slender, tarsi two-segmented, claws with pulvilli.

Abdomen. Lateral margins subparallel and straight, deltg VII truncate posteriorly; pattern of apodemal impressions of deltg II-VII and tergal disk not clearly discernible, supposed to be arranged as 2(1):1:1.

Venter. Obscured by impurities; sternites III-VI separated by transverse sutures.

Remarks. The general habitus resembles at first glance a specimen of the subfamily Aradinae or Mezirinae . However Pachytylaradus is distinguished from Aradinae by the structure of head and the presence of pulvilli, from Mezirinae by lack of metathoracic scent glands. This new genus differs from the other extant subfamilies ( Aneurinae , Calisiinae , Carventinae , Chinamyersiinae , Isoderminae and Prosympiestinae) (Usinger & Matsuda, 1959) and the Burmese amber fossil Archearadinae Heiss & Grimaldi, 2002, basically by its habitus and the set of body structures listed above but not shared by one of them. Pachytylaradus might be classified as a member of a new subfamily, which should be based on a phylogenetic analysis as a result of a careful comparison and evaluation of all available characters including other Burmese amber taxa. This is a future study, presently not yet feasible.