Prosoglypta Shavrin & Smetana, 2019

Shavrin, Alexey V. & Smetana, Aleš, 2019, Prosoglypta, a new remarkable genus from Vietnam (Coleoptera: Staphylinidae: Omaliinae: Omaliini), Zootaxa 4609 (2), pp. 388-394 : 389-391

Prosoglypta Shavrin & Smetana , gen. nov.

( Figs. 1−15 )

Type species: Prosoglypta alesenkae Shavrin & Smetana , sp.nov.

Description. Body strongly convex, oblong; reddish-brown ( Fig. 1 ). Punctation of forebody moderately large and dense, markedly sparser and smaller on head and deeper on pronotum. Dorsal surface of body very glossy, without microsculpture between punctures, without pubescence except of several long setae on apical part of clypeus and dorsolateral portions of head between eyes and middle elevation, short setae along lateral and middle portions of pronotum and elytra, and very short and sparse recumbent setae on abdominal tergites.

Head markedly narrower than pronotum, transverse, with sharp nuchal constriction and obtuse postocular ridge, with a pair of ocelli at level of posterior margins of eyes, with very narrow impressions near anterior margins of each ocellus and long furrows beginning from inner lateral margin of ocelli between relatively convex shield-like elevated middle portion, gradually widened apicad. Lateroapical portions of middle elevation with slight and relatively wide impressions at level of antennal insertions. Eyes large and strongly protruded, four to five times as long as surface between basal margin of eye and postocular ridge (if seen laterally); dorsal margins of eyes with thin slightly elevated infraorbital ridge; dorsal surface slightly convex between infraorbital ridge and lateral margin of middle elevation. Antennal insertion concealed under shield-like elevated middle portion of head; antenna slightly shorter than head and pronotum combined, with last five antennomeres forming a loose club, first six antennomeres with scattered long setation, remaining antennomeres with additional dense short setae. Labrum ( Fig. 3 ) short, transverse, slightly concaved anteriorly, with four pairs of long setae on anterolateral portions and two rows of short setae in middle of apical portion. Mandibles ( Figs. 4 ) moderately broad, each with acute apex; right mandible with more curved apex and small obtuse tooth at distal third of cutting edge; articulating molar lobes with moderately strong acute dents almost along entire lateral margin. Maxilla ( Fig. 6 ) narrow; galea oblong, with dense long apical setae; lacinia narrow, straight on outer margin, with row of small thorns on apical third of inner margin, apex with feebly curved tooth; maxillary palpus moderately long, second palpomere about as long as and slightly wider than third palpomere, apical palpomere slightly narrower and longer than penultimate palpomere, from apical third tapering toward apex. Labium ( Fig. 5 ) distinctly bilobed, palpus three-segmented, narrow, each segment distinctly longer than wide, apical segment narrower than penultimate segment. Mentum ( Fig. 5 ) moderately large, trapezoidal, with four long setae on anterior third. Gular sutures widely separated from each other at level of posterior margins of eyes, strongly divergent posteriad. Each gena with distinct, moderately protruded anterolateral extensions, visible in front of anterior margins of eyes, if seen dorsally.

Pronotum transverse, markedly convex, without longitudinal impressions, lateral margins narrowly and slightly explanate, indistinctly serrate on anterior half; posterolateral portions bearing indistinct, wide lateral pits. Prothorax short, strongly transverse, with moderately short acute intercoxal process reaching about middle of front coxae; surface with sparse and large deep punctures. Mesothorax short, with distinct, long median carina, reaching apex of very long and narrow intercoxal process extending to posterior third of mesocoxae that are narrowly separated from each other. Scutellum wide, triangular. Metathorax markedly transverse, convex, with deep mesocoxal cavities and moderately wide and short intercoxal process, obtuse apically and extending to mesosternal process; surface with sparse, moderately large and deep punctation, denser on lateral portions.

Legs short; apical half of pro- and mesotibiae with spines on inner and outer margins, markedly denser on protibiae; metatibiae without spines, covered with long setae; shape of hind trochanter, and shape and setation of protarsomeres 1−4 sexually dimorphic (for details see the species description); tarsi short, apical tarsomere equal to or slightly longer than previous four tarsomeres combined.

Elytra markedly convex, moderately short and wide, extending to apical margin of abdominal tergite IV or basal margin of abdominal tergite V, weakly widened posteriad, with moderately broad epipleura and well-developed rounded humeri, with slightly serrate lateral margins. Wings fully developed.

Abdomen convex, distinctly narrower than elytra, with a pair of moderately wide tomentose spots (wing-folding patches) on middle of abdominal tergite IV; apical margins of tergites IV and V with brickwall sculpture, apical margin of tergite VII with very narrow, indistinct palisade fringe.

Male. Apical abdominal (genital) segment as in Fig. 10 . Aedeagus with fused parameres ( Fig. 14 ).

Female. Accessory abdominal sternite ( Fig. 13 ) wide and oval. Sclerotized spermatheca missing. Gonocoxites moderately wide and long, with thin short styli ( Fig. 13 ).

Immature stages unknown.

Discussion. Based on the shape of the strongly convex and short body, with elevated middle portion of head separated from each lateral side by a distinct, long furrow, as well as on the presence of conspicuous process of anterolateral portion of each gena, visible dorsally, the new genus is similar to two genera of Omaliini : Pycnoglypta and Prosopaspis . Despite the similar habitus with Pycnoglypta , as well as in the presence of well-developed neck constriction, shapes of apical portions of mandibles and transverse metathorax, absence of median carina on the prothorax, contiguous position of the mesocoxae, general shape of the aedeagus with the presence of the median lobe, and well defined female accessory sclerite ( Shavrin 2016), Prosoglypta gen. nov. differs from it by the presence of ocelli, significantly protruded eyes, and by the absence of sclerotized spermatheca. Based on the shapes of eyes and gonocoxites, presence of the ocelli, modified male adhesive setae on protarsomeres 1−4, a pair of very long spines in basal portion of the internal sac, and the absence of the sclerotized spermatheca ( Smetana 1987), Prosoglypta gen. nov. is similar to Prosopaspis , from which it differs by the narrower elevation of the middle portion of head, shorter conspicuous process of anteriolateral portions of each gena, shapes and structure of gular sutures (more modified and coriaceous in Prosopaspis ), presence of the preapical tooth in left mandible and nuchal constriction, significantly shorter elytra, long median carina on mesothorax ( Prosopaspis has two moderately strong median ridges on it), significantly narrowly separated mesocoxae, absence of the median carina on the prothorax, as well as by presence of the median lobe and basal pieces of the aedeagus.

From both these genera, Prosoglypta gen. nov. differs by the following characters: 1) dorsal and ventral margins of eyes with narrowly elevated infraorbital ridge; 2) antenomeres 7−11 forming a loose club; 3) lateroapical margins of the pronotum indistinctly serrate; 4) middle portion of mesothorax with distinct long carina; 5) hind trochanter of male with very long projection, as that in some western Palaearctic species of Hapalaraea Thomson, 1858 ( Zanetti 1983) ; 6) unusual structure of the aedeagus, with fused parameres.

Etymology. The feminine generic name is a combination of parts of the existing names Prosopaspis and Pycnoglypta .

Figures

FIGURES 1–2. Habitus of holotype (Fig. 1) and location of the type locality in northern Vietnam (Fig. 2) of Prosoglypta alesenkae Shavrin & Smetana, gen. et sp. nov. Scale bar: 1.0 mm.

FIGURES 3–6. Mouthparts (dorsal view) of Prosoglypta alesenkae Shavrin & Smetana, gen. et sp. nov.: 3–labrum, 4–mandibles (left and right), 5–labium and mentum, 6–maxilla (right). Scale bars: 0.1 mm.

FIGURES 7–13. Male hind leg (Fig. 7) and abdominal segments of Prosoglypta alesenkae Shavrin & Smetana, gen. et sp. nov. (Figs. 8–13): 8–male tergite VIII (dorsal view), 9–male sternite VIII (ventral view), 10–male genital segment, 11–female tergite VIII (dorsal view), 12–female sternite VIII (ventral view), 13–female genital segment and accessory sclerite (dorsal view). Scale bars: 0.1 mm.

FIGURES 14–16. Aedeagus of Prosoglypta alesenkae Shavrin & Smetana, gen. et sp. nov.: 14–aedeagus, parameral view (outline of internal sac shown as point line), 15–internal sac, parameral view, 16–aedeagus, lateral view. Scale bars: 0.1 mm.