Platygeniops Krikken, 1978

Jákl, Stanislav & Krikken, Jan, 2011, Description of a second species in the enigmatic Southeast Asian genus Platygeniops (Coleoptera: Scarabaeidae: Cetoniinae), Zootaxa 3003, pp. 63-68 : 64-65

Genus Platygeniops Krikken, 1978

Redescription. Head. Clypeus bisinuate in front, rounded anterolaterally; sides feebly, simply marginate all around; clypeopleuron absent. Clypeolateral ridges straight to slightly curvilinear near eye canthus, lateral declivities narrowly distinct in full-face view. Clypeal and frontal surface generally flat to slightly convex, without any additional protrusions or other modifications. Clypeus and frons strongly punctate (punctate-striolate), virtually glabrous. Eye canthus extending laterad, simple, straight, narrow. Eyes large and very distinct in full-face view.

Pronotum. Prothorax wide, base only slightly narrower than elytral base. Pronotal disc generally flat. Pronotal sides rounded, evenly convergent in front, subparallel behind, lateral border entirely marginate. Anterior margin of pronotum very slightly raised; anterior declivity slightly convex, unmodified. Pronotal apex without discrete protrusion(s). Basal border of pronotum slightly bisinuate (medial section convex in dorsal view), at most finely marginate; posterolateral angle weakly rounded, not (or hardly) shifted forward relative to basomedian border. Posterolateral area of pronotum unmodified, basomedian surface of pronotum generally flat or very slightly convex, without protrusions or impressions. Pronotum generally with small, simple to arcuate-striolate punctures mainly concentrated along borders; pilosity absent or sparse. Scutellum large, simply elongate-triangular (sides basally not convergent), apex acute; sides fitting closely to elytra; surface punctate-striolate.

Elytra. Elytral strial-interstrial pattern poorly defined, discal surface superficially quasi-multicostate, basal part of disc slightly swollen. Elytra on cross-section deplanate; discolateral transition subabrupt, may be delimited by costa; surface lacking salient structural or sculptural features; disc between “costae” with (partly ill-defined) rows of punctures and (partly confluent) arcuate striolae. Juxtasutural margin of elytron not elevated (at most with fine impressed groove). Humeral umbone distinct, intrahumeral depression absent; anteapical umbone slight; apicosutural angle of elytron weakly rounded. Distal elytral declivity gradual, unmodified. Posthumeral elytral emargination virtually absent; elytral epipleuron almost straight, very narrow. Elytral surface locally (distally) with pilosity; setae varying from abundant, inconspicuous stubbles (short, stiff setae) to dense (sub)erect bristles. General shape of elytron more or less elongate, lateral outline in dorsal view more or less straight and parallel.

Head appendages. Antennal lamellae (male and female) with elongate-subelliptic outline, about as long as antennomeres 2–7 combined or slightly shorter; antennal lamellae unmodified, scapus slender, simply claviform. Labial palpus with 3 palpomeres, palpomere 1 short. Mandibles strongly sclerotized. Maxillary galea and lacinia penicillate-dentate. Maxillary palpus with 3 palpomeres. Mentum flat to (medially) slightly concave, shortly bisinuate-bilobate in front.

Ventral parts. Preprosternum more or less tectiform, lacking apophysis. Procoxae (sub)contiguous. Postprosternum unmodified. Propectoral sides unmodified, surface posteriorly concave. Mesosternal surface unmodified, striolate, narrowly interposed between mesocoxae; no distinct mesometasternal protrusion between mesocoxae. Mesepimeron (in dorsal view) distinctly convex. Metacoxae (sub)contiguous. Abdominal sides (in dorsal view) at most just distinct (largely covered by elytra, only distally slightly more exposed); ventro-dorsal transition gradually convex. Distal abdominal spiracles visible, not covered by elytra; propygidial constriction narrow at spiracular level, spiracles not raised. Ventral side with numerous setae; metasternum and abdominal sternites abundantly annulate-arcuate-striolate; number of visible abdominal sternites (ventrites) over midline 6, plus lateral part of basal ventrite on either side; anal sternite unmodified, median length different according to sex and species (shorter in female); impression of abdominal venter strong in male, not impressed in female. Pygidium generally evenly, variably convex, broadly transverse, with (at most finely marginate) anal border, lacking broadly reflexed anal margin and lacking any distinct surface protrusions; pygidium distinct from above, surface with conspicuous but fine (braided) striolation-rugulation; pygidial pilosity varies, usually with distinct pilosity.

Male genitalia. Parameres generally broadly lobiform, laterally rounded in full-face view, inner edges closed, subcontiguous (curved downward in lateral view; tips not bifid, without appendages); parameral surface entirely glabrous; intermediate piece long, slightly curved (in lateral view), slender (narrower than parameres combined); basal piece short.

Legs. Procoxa conically protuberant, distance of prothoracic edge to coxa wide. Protibia with 3 distinctly separated, acute, external denticles (both sexes), with inferior-longitudinal ridge (which is terminally not dentate); lacking basal-internal projection; terminal protibial spur tapering. Mesotarsi and metatarsi virtually as long as tibiae; 5 tarsomeres on all legs; tarsal claws simply sickle-shaped (lacking extra denticle); tarsomere 1 not distinctly longer than subsequent tarsomeres, all tarsomeres claviform to subcylindrical, pilosity sparse. Protarsomeres 1–4 subequal in length, unmodified. Mesofemora and metafemora unmodified. Outer side of both mesotibiae and metatibiae with a single anteapical protrusion; mesotibiae and metatibiae in cross-section more or less rounded; apex of mesotibia bidentate, apex of metatibia tridentate; terminal spurs of both tibiae tapering, movable. Metacoxal lateral side broad, finely marginate, with distinct posterolateral angle.

General. Predominant coloration black and/or red (red-brown); dorsum simply pigmented, without extra cover of any kind, any color pattern simple or limited. Dorsum (particularly elytra) with variably dense, short pilosity. General microsculpture of surface punctate to (annulate/arcuate) striolate, locally dense, contiguous, or braided. Sexual dimorphism very slight. Habitus robust (may be slightly complanate, in lateral view), total body length approximately 2.5–3.5 cm.

Type species. Platygeniops exspectans Krikken, 1978 (by original designation).

Distribution. The two known species have been recorded from Borneo, Malaysia, Thailand, and Myanmar.

Platygeniops elongatus Platygeniops exspectans

Body shape longer, slender, complanate shorter, plump Dorsal color largely red entirely black Elytral pilosity densely set brown bristles inconspicuous pale stubbles