Tetradelus sinensis, 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 : 469-470

Tetradelus sinensis sp.n.

( Figs. 36–40 )

Type material examined. Holotype ♂ (dissected; part of right tibia and tarsus are missing): ‘ China Yunnan, 1800m | LIJIANG 23.6.-21.7. | 26.53N 100.18E | lgt. S. Becvar 1992’ <printed>, ‘cfr | Tetradelus [handwritten] | det. Zanetti 95.’ <printed>, ‘HOLOTYPE | Tetradelus | sinensis sp.n. | Shavrin A.V. des. 2022’ <red, printed> ( MHNG).

Description. Measurements: HW: 1.00; HL: 0.43; AL: 1.33; OL: 0.19; PL: 0.77; PW: 1.16; ESL: 1.12; EW: 1.36; AW: 1.31; MTbL: 0.77; MTrL: 0.40 (MTrL 1–4: 0.15; MTrL 5: 0.25); AedL: 0.80; TL: 4.06.

Body wide, slightly convex ( Fig. 36 ), reddish-brown, with slightly darker head and paler abdomen; antennomeres 6−11 brown; mouthparts, antennomeres 1−5 and legs yellow (two preapical maxillary palpomeres slightly darker). Head with very dense, fine punctation, sparser and larger in middle and coarser and denser on infraorbital ridges (frontal part of vertex without punctures); neck without punctures except of apical portion with moderately sparse and fine punctation; punctation of pronotum dense, slightly denser and finer than that on middle portion of head; scutellum with several fine punctures; punctation of elytra very dense, slightly denser than that on pronotum; abdominal tergites with very dense, moderately deep and coarse punctation, somewhat finer and sparser on abdominal tergite VII. Body glossy; forebody without microsculpure except of frontal portion of vertex with fine transverse meshes and neck with indistinct isodiametric microreticulation; abdominal tergites with very dense isodiametric microsculpture. Head with erect and moderately long setation on apical portion of vertex and with several short and erect lateral setae; lateral portions of pronotum with several short setae; lateral margins of each elytron with very dense and short pubescence; abdomen with very dense, short, accumbent pubescence.

Head transverse, more than twice as broad as long, with slightly elevated middle portions and infraorbital ridges. Supra-antennal prominences narrowly elevated. Postantennal depressions wide and deep connected with lateral depressions between infraorbital ridges and middle portion; median part with indistinct, moderately narrow longitudinal impression.Anterolateral portions between antennal insertion and anterior margin of eye with moderately deep semicircular notch. Anteocellar foveae and occipital furrow missing. Eyes large and convex. Postocular ridge distinct, subacute; surface between postocular ridge and posterior margin of eye about as long as three nearest ommatidia. Ocelli large, slightly convex, located about at level of postocular ridges; distance between ocelli about as long as distance between ocellus and posterior margin of eye. Apical segment of maxillary palpomere very long, more than four times as long as preapical palpomere, narrow in basal part, slightly broadened in middle and gradually narrowed toward subacute apex. Antenna reaching apical margins of elytra when reclined, antennomeres 5−11 with moderately dense and long setation; basal antennomere about two and a half times as long as broad, antennomere 2 slightly elongate and distinctly narrower than basal antennomere, 3 narrow and distinctly longer than 2, 4 about twice shorter than 3, 5 distinctly longer and slightly broader than 4, 6 slightly shorter than 5, 7 slightly shorter than 6, 8 slightly shorter and broader than 7, 9−10 transverse, distinctly broader and longer than 8, apical antennomere about 1.5 times as long as preceding antennomere, from middle gradually narrowed toward subacute apex.

Pronotum 1.5 times as broad as long, slightly broader than head, from widest middle distinctly more narrowed posteriad than anteriad; anterior margin slightly and widely concave, slightly narrower than somewhat straight posterior margin; anterior angles widely rounded; posterior angles subacute; lateroapical and lateral margins narrowly bordered; middle portion with indistinct wide and paired slightly deeper impressions in mediobasal third; laterobasal portions widely impressed.

Elytra distinctly broader than long, 1.4 times as long as pronotum, reaching apical margin of abdominal tergite III, with lateral sides distinctly and narrowly bordered and slightly explanate; middle portion of each elytron with indistinct longitudinal elevations, diagonally stretching from apical toward posterior portions; posterior margin straight. Hind wings fully developed.

Legs moderately long, with inner and outer margins of pro- and mesotibia covered by dense and short setation; each protibia slightly broadened apicad; protarsi 1.9 times as long as protibia, with very long apical protarsomere, 1.6 times as long as preceding tarsomeres.

Abdomen slightly narrower than elytra, with two small suboval tometose spots in middle part of abdominal tergite IV and two smaller spots in middle of tergite V, and with narrow palisade fringe on apical margin of tergite VII.

Male. Apical margin of abdominal tergite VIII slightly concave ( Fig. 39 ). Apical margin af abdominal sternite VIII somewhat truncate ( Fig. 40 ). Aedeagus narrow, from widest basal portion gradually narrowed toward middle part of median lobe and more strongly narrowed from middle toward apex splitted by narrow and moderately deep indentation into two apical lobes; parameres very wide, slightly narrowed toward apical portions, not reaching apex of median lobe, with two moderately long apical and two preapical setae; internal sac without visible fields of thorns, with very long flagellum significantly broadened in basal portion ( Fig. 37 ). Lateral aspect of aedeagus as in Fig. 38 .

Female unknown.

Comparative notes. Based on the general shape of the body and the aedeagus, Tetradelus sinensis sp.n. is similar to T. trigonuroides Fauvel, 1904 , originally described from Sikkim, India ( Fauvel 1904; morphological features see also in Cameron (1930) & Steel (1966)), but differs from it by the smaller and paler body, the presence of median impressions on the pronotum, more narrowed basad, different shapes of longitudinal elevations of the elytra, wider parameres and different shape of the apex of the median lobe (if compare Fig. 6 in Steel (1966) and Fig. 37 ).

Distribution. Tetradelus sinensis sp.n. is at present known only from the type locality in Yunnan, China.

Bionomics. The specimens were collected at an elevation of 1800 m a.s.l. The detailed ecological data are unknown.

Etymology. The specific epithet refers to the country where the new species was collected.

Figures

FIGURES 36–40. Tetradelus sinensis: 36–habitus, dorsal view, 37–aedeagus, parameral view, 38–aedeagus, lateral view, 39– male abdominal tergite VIII, 40–male abdominal sternite VIII. Scale bar: 1.00 mm (Fig. 37), 0.10 mm (Figs. 38–41).

FIGURES 1–8. Acrolocha wahuiense: 1–aedeagus, parameral view, 2–aedeagus, lateral view, 3–male abdominal tergite VIII, 4–male abdominal sternite VIII, 5–female abdominal tergite VIII, 6–female abdominal sternite VIII, 7–female accessory sclerite, 8–spermatheca. Scale bar: 0.10 mm.