Megalinus nonvaricosus Zhou & Zhou

ZHOU, YU-LINGZI, BORDONI, ARNALDO & ZHOU, HONG-ZHANG, 2013, Taxonomy of the genus Megalinus Mulsant & Rey (Coleoptera: Staphylinidae, Xantholinini) and seven new species from China, Zootaxa 3727 (1), pp. 1-66 : 19-22

Megalinus nonvaricosus Zhou & Zhou , sp. nov.

(Fig. 5A–H; Fig. 5-1A–H)

Type materials. Holotype: male, CHINA: Ningxia: Xiji co. (E 105.7291, N 35.9639), Xie Chengjun collected ( IZ-CAS); paratypes: CHINA: Ningxia: Haiyuan co. : Lingguangsi (E 105.6408, N 36.5633), one female, Ren Guodong collected ( IZ-CAS).

Description

Measurements. BL= 9.8 mm, FL=5.0 mm, HL= 1.4 mm, HW= 1.2 mm, PL= 1.7 mm, PW= 1.2 mm, EL= 1.7 mm, EW= 1.5 mm.

Body cylindrical (Fig. 5D), large sized. Body brown, except head darker and elytra brunneus. Legs and antennae entirely brown, except apical 1/3 of last antennomere yellowish. Maxillary and labial palpi brown.

Head (Fig. 5A). Subrectangular (HL to HW ratio 1.2), temple slightly dilated, posterior angles rounded. Dorsal integument shiny, distributed with round, densely-distributed, small-sized punctures, interspaces between punctures 1–2 punctures’ diameter, except impunctate longitudinal impunctate band (0.25 mm width); also with some microstriae along posterior margin. Each side of cranium also with frontal puncture on epistoma, anterolateral puncture near antennal insertion, 3–4 small punctures on frontal region, midlateral puncture approximately a distance of 5–6 punctures’ diameter from dorsal margin of eye, temporal puncture and occipital puncture not obvious; deflexed portion of head with 2–3 rows of punctures. Frontal furrows slightly arcuate or substraight, deeper and longer than anteocular furrows; anteocular furrows of subequal length to eye, arriving line connecting rearmost of each eye. Eye of small size, near 1/3 of temple length (eye: temple = 0.30: 0.90 mm), protruding laterad. Epistoma protruding forwards, of subrectangular shape, anterior margin subtruncated. Distance between antennal insertions 0.36 mm, wider than that from antenna to eye (0.30 mm).

Antennae. Scape stout, thickened apically, longer than three subsequent antennomeres combined, 0.60 mm; antennomere II elongate, 0.15 mm, equal to III; III elongate, 0.15 mm; IV and V transverse, subequal in length, 0.090 mm; last antennomere of medium length, 0.21 mm, subequal to preceding two antennomeres combined.

Neck. Medium width (0.48 mm), slightly wider than 1/3 of head width.

Pronotum (Fig. 5B). Subrectangular, distinctly elongated (PL to PW ratio 1.4), longer than head, but of same width. Anterior angles well-developed and slightly widened, lateral margins subparalleled or slightly sinuate, posterior angles broadly rounded. Integument shiny, microsculpture missing, micropunctures presenting. Two rows of setiferous punctures presenting on each side, admedian row consisting of 8–9 punctures; lateral row, slightly curvedly arranged, of 7–9 punctures; other irregular punctures scattered near anterior margin.

Mesoscutellum. Shiny, extensively covered with distinct microstriae, and with several small, irregular punctures.

Elytra (Fig. 5C). Subquadrated (EL to EW ratio 1.1), obviously wider than pronotum, but of same length. Humeri well developed, lateral margins distinctly widened posteriorly, hind margin slightly arcuate. Integument shiny and flattened, without microsculpture; each elytron with each elytron with 6–8 rows of medium-sized punctures; deflexed portion with 3–4 rows of smaller setiferous punctures.

Abdomen. Cylindrical, broadest at segment VI. Tergites III–VII shiny, covered with distinctly transverse microstriae, also distributed with small setiferous punctures, interspaces between punctures near 2–3 punctures’ diameter, denser laterobasally; each tergite with impunctate basal impression which bearing obvious polygonal reticulum. Surface between two basal transverse carinae impunctate, but bearing distinct polygonal reticulum. All abdominal sternites shiny, with microsculpture and setiferous punctures as those on tergites.

Male. Abdominal segment VIII entirely covered with setiferous punctures, except a narrow medial longitudinal impunctate band; posterior margins of tergite VIII slightly emarginated medially, that of sternite VIII subtruncated (Fig. 5-1A, B). Tergite IX symmetrical, connected mediobasally. Sternite IX symmetrical, with acuminate base and emarginated posterior margin (Fig. 5-1C). Tergite X symmetrical, with subtruncated base and broadly emarginated posterior margin (Fig. 5-1D), in situ broadly exposed between tergite IX. Median lobe of aedeagus oviform and oblong, medium sized (Fig. 5G, H; Fig. 5-1E, F), basal piece without transparent, membranous medial-longitudinal band; basal bulb 1.10 mm long, anterior portion subcylindrical and short (Fig. 5E, F), 0.25 mm, slightly short than 1/4 of basal bulb. Parameres symmetrical and long, slightly longer than 1/3 of basal bulb. Internal sac coiled one time at basal 1/3, extensively bearing scales.

Female. Posterior margin of sternite VIII gradually sharpened backwards (Fig. 5-1G;). Genital segment medium sized (Fig. 5-1H), 0.80 mm long, sternite with slightly bisinuate basal margin, supplementary sclerites medium sized, 0.35 mm long, overlapped entire basal margin of genital sternite.

Distribution. China (Ningxia).

Etymology. The specific epithet is derived from the Latin words " non - "(non) and " varicosus " (variable).

Remarks. This species could be distinguished from its congeners by: 1) head subrectangular, HL to HW ratio 1.2; 2) temple not obviously dilated or subparalleled; 3) head distributed with small, round punctures; 4) eye of small size, near 1/3 of temple length (eye: temple = 0.30: 0.90 mm), flattened and not protruding laterad; 5) anterior angles of pronotum slightly protruding and angulated; 6) tergites III–VII covered with superficial transverse microstriae; 7) posterior margins of tergite VIII slightly emarginated medially; 8) Internal sac coiled one time at basal 1/3, extensively bearing scales.