Paraphloeostiba gracillima, Shavrin, 2022

Shavrin, Alexey V., 2022, New species and records of Omaliini McLeay, 1825 from Eastern Palaearctic and Oriental regions (Coleoptera: Staphylinidae: Omaliinae), Zootaxa 5169 (5), pp. 457-471 : 462-464

Paraphloeostiba gracillima sp.n.

( Figs. 16–23 )

Type material examined. Holotype ♂: ‘ THAILANDE Chiang | Mai, Doi Suthep | 1180 m, I-II.1986 (BF) | P. Schwendiger’ <printed>, ‘HOLOTYPE | Paraphloeostiba | gracillima sp.n. | Shavrin A.V. des. 2022’ <red, printed> ( MHNG)

Paratypes: 8 ♂♂ (two specimens dissected), 16 ♀♀ (one specimen dissected): same data as the holotype, with additional red printed label : ‘ PARATYPE | Paraphloeostiba | gracillima sp.n. | Shavrin A.V. des. 2022’ (2 ♂♂, 2 ♀♀: cSh; 6 ♂♂, 14 ♀♀: MHNG) .

Description. Measurements (n=25): HW: 0.40–0.46; HL: 0.22–0.27; AL (holotype): 0.53; OL: 0.11–0.12; PL: 0.30–0.32; PW: 0.54–0.59; ESL: 0.56–0.58; EW: 0.74–0.76; AW: 0.72–0.75; MTbL (holotype): 0.30; MTrL (holotype): 0.22 (MTrL 1–4: 0.05; MTrL 5: 0.17); AedL: 0.35–0.36; TL: 1.70–2.25 (holotype: 1.85).

Body yellow-brown to reddish-brown, with darker middle portion of pronotum, and lateral and posterior portions of elytra; antennomeres 6–11 brown; mouthparts, antennomeres 1–5, laterobasal portions of pronotum and apical segments of abdomen in some specimens, and legs yellow. Head with irregular, indistinct, fine and sparse punctation, denser on vertex and infraorbital ridges (some paratypes without punctures in middle); neck without or with very fine and sparse punctation; pronotum with moderately dense punctation, distinctly larger than that in head, finer and sparser in mediobasal and larger and coarser in laterobasal portions (some paratypes without punctures along midline); scutellum without visible punctures; elytral punctation about as that in pronotum, but slightly larger and deeper; abdominal tergites with fine and moderately dense punctation (indistinct in some paratypes), somewhat larger on abdominal tergite VII. Head with regular and strong microsculpture, slightly transverse on vertex and isodiametric in middle portion; pronotum with dense and moderately strong microreticulation about as that on middle part of head; scutellum with fine transverse meshes; microsculpture of elytra dense, slightly larger than that on pronotum; abdomen with strong and dense isodiametric sculpture, transverse in basal portions of abdominal tergites IV–VI.

Head slightly elevated in median and posterior portions between ocelli and eyes, with moderately wide postantennal depressions, 1.7–1.8 times as broad as long, with short and deep anteocellar foveae slightly not reaching middle of eyes; postocular carina distinct, acute or obtuse, surface between postocular ridge and posterior margin of eye as long as diameter of two nearest ommatidia. Apical maxillary palpomere long, about three times as long as preceding segment. Antennae short, reaching basal margin of elytra when reclined, with distinctly transverse antennomeres 6–10, progressively broadened apicad; basal antennomere about twice as long as broad, antennomere 2 slightly narrower than basal antennomere, 3 narrow, about as long as 2 or slightly longer, 4 small and suboval, about as long as broad, 5 suboval, slightly longer and broader than 4, 6 slightly longer than 5 and about 1.5 times as broad as long, 7–8 slightly longer than 6 and about twice as broad as long, 9–10 slightly broader than 8, apical antennomere about twice as long as 10, from middle gradually narrowed toward rounded or subacute apex.

Pronotum slightly convex, 1.8 times as broad as long, 1.2–1.3 times as broad as head, widest in about middle, slightly more narrowed posteriad than anteriad; anterior angles widely rounded, not protruded apicad; posterior angles obtuse; anterior margin somewhat straight, about as long as posterior margin of slightly shorter; middle portion usually without impressions or with very indistinct and wide paramedian impressions in some paratypes; laterobasal impressions wide and moderately deep.

Elytra 1.3 times as broad as long, 1.8 times as long as pronotum, slightly broadened apicad; posterior margin straight.

Metatarsi 1.3 times as long as metatibia.

Abdomen slightly narrower than elytra, with two very small and round tomentose spots in middle of abdominal tergite IV; apical margin of abdominal tergite VII with very narrow palisade fringe.

Male. Posterior margin of abdominal tergite VIII truncate ( Fig. 18 ). Posterior margin of abdominal sternite VIII widely concave ( Fig. 19 ). Aedeagus with wide basal bulb, strongly narrowed toward narrow rounded apex; parameres narrow, distinctly broadened in apical portions, slightly not reaching apex of median lobe, with two long apical setae and several short setae on inner and outer margins of each paramere; internal sac complicated, narrow and long, with several sclerotized elongate structures in middle and basal portions ( Fig. 16 ). Lateral aspect of aedeagus as in Fig. 17 .

Female. Posterior margins of abdominal tergite VIII ( Fig. 20 ) and sternite VIII ( Fig. 21 ) truncate. Female accessory sclerite with wide basal part, significantly narrowed towards long apical portion ( Fig. 22 ). Spermatheca as in Fig. 23 .

Comparative notes. Regarding the coloration and the length of the body, features of the microsculpture of the forebody, shapes of the antennomeres and the slightly convex pronotum with indistinct paramedian impressions, it is similar to P. subuliformis sp.n. It can be distinguished from this species by the somewhat finer and denser punctation of the more transverse pronotum, shorter parameres with narrower apical portions, broader median lobe, the different morphology of the internal sac and different shape of the female accessory sclerite. The general shape of the aedeagus of P. gracillima sp.n. and P. subuliformis sp.n. is somewhat similar to P. rhopalocera (Cameron, 1928) , known from Sumatra and New Guinea, but both new species can be distinguished from it by the larger body, darker elytra, distinctly narrower antennomeres 7–10, and different shapes of the apical portion of the median lobe and the parameres.

Distribution. The new species is at present known only from the type locality in Chiang Mai, Thailand.

Bionomics. The specimens were collected at an elevation of 1180 m a.s.l. The detailed ecological data are unknown.

Etymology. The specific epithet is derived from the Latin adjective gracilis, - e, (slender). It alludes to the narrow apical portion of the median lobe.

Figures

FIGURES 16–23. Paraphloeostiba gracillima: 16–aedeagus, parameral view, 17–aedeagus, lateral view, 18–male abdominal tergite VIII, 19–male abdominal sternite VIII, 20–female abdominal tergite VIII, 21–female abdominal sternite VIII, 22–female accessory sclerite, 23–spermatheca. Scale bar: 0.10 mm.