Metolinus gardneri (Cameron, 1945)

Zhou, Yu-Lingzi & Zhou, Hong-Zhang, 2011, Taxonomy of the genus Metolinus Cameron (Coleoptera, Staphylinidae, Staphylininae, Xantholinini) from China with description of three new species, ZooKeys 112, pp. 53-87 : 63-65

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Metolinus gardneri (Cameron, 1945)


5. Metolinus gardneri (Cameron, 1945) Fig. 14 A–HFig. 14-1 A–E

Cameron 1945: 68 ( Leptacinus ; Type locality: United Provinces: Dehra Dun, New Forest); Herman 2001: 3674 ( Leptacinus ; catalog); Bordoni 2002: 412 ( Metolinus ; characters; China, Thailand, Myanmar, Malaysia, Laos, Vietnam); Bordoni 2003a: 50 ( Metolinus ; Malaysia, W-Perak, 30 km SE Ipoh; Smetana 2004: 691 ( Metolinus ; catalog; Yunnan, India); Bordoni 2007: 71 ( Metolinus ; catalog).

Material examined.

CHINA: Yunnan: Xishuangbanna Dai Autonomous Prefecture, 1 female, 860 m, 11.II.2004, Wu Jie & Bai Dayuan collected (IZ-CAS); Yaoqu (E 101.6659, N 21.7007), 1 male, 1 female, 940 m, 19.II.2004, Wu Jie collected (IZ-CAS); Menglun town (E 100.9876, N 22.1711), 1ex., 620 m, 21.II.2004, Wu Jie & Zhang Jiaolin collected (IZ-CAS); Menglun town, 1 male, 730 m, 13.II.2004, Wu Jie collected (IZ-CAS); Mengla co., Longmen village, Xiaoniupeng (E 101.3252, N 21.3095), 1 female, 1035 m, 07.X.2010, Zhou Yulingzi collected (IZ-CAS); Mengyang town, 1 male, Kungenaban 2nd village (E 100.9876, N 22.1711), 910 m, 09.X.2010, collected by Lvliang (IZ-CAS).


Measurement. BL=4.9 mm, FL=2.7 mm, HL=0.80 mm, HW=0.63 mm, PL=0.90 mm, PW=0.63 mm, EL=0.89 mm, EW=0.69 mm.

Body small sized and nearly compressed. Head, pronotum, mesoscutellum and elytra entirely black. Abdomen dark brown, posterior margin of segment VII and VIII paler. Legs dark brown, tarsi lighter. Antennae brown except apical 1/2 of 11th segment yellowish. Maxillary palpi and labial palpi light brown.

Head(Fig. 14-1A). Subrectangular (HL to HW ratio 1.3), tempora slightly widened posteriorly, posterior angles rounded. Dorsal integument shiny, extensively covered with distinct transverse microstriae, and sparse, scattered setiferous punctures of medium size, distance between punctures ca. 3 puncture diameters. On each side symmetrically with frontal puncture on the epistoma, 2 antennal punctures near antennal insertion, ocular puncture near medial margin of eye (ca. 3-4 puncture diameters from eye), temporal puncture at posterior 1/5 and occipital puncture at lateral 1/3; deflexed portion of tempora with smaller setiferous punctures, and microstriae same as on dorsal integument. Frontal furrows superficial and short, shorter than 1/2 of eye length. Ocular furrows of medium length, subequal to eye length. Eye of medium size, slightly longer than 1/3 of temple length (eye: temple=0.18:0.42 mm), and slightly protruding laterad. Epistoma protruding forwards, anterior margin subtruncated, dorsally flat and broad, as wide as 1/2 of eye length. Distance between antennal insertions ca. 0.23 mm, obviously wider than distance from antenna to eyes (ca. 0.15 mm). Ventral integument shiny, with same microstriae and setiferous punctures as on dorsal integument. Mentum with two pairs of setae inserted at anterior angles in addition to other irregularly scattered setae, submentum with 3 pairs of setae. Gular sutures fused at middle, and separated at base of occiput. Gular plate devoid of punctures, but spread with distinct transverse microstriae.

Antennae(Fig. 14-1B). Scape stout, thickened apically, longer than three subsequent antennomeres combined, ca. 0.30 mm; 2nd elongate, ca. 0.075 mm, distinctly longer than 3rd; 3rd globular, ca. 0.060 mm; 4th and 5th subequal, ca. 0.053 mm; last antennomere medium long, ca. 0.11 mm, as long as preceding 2 antennomeres combined.

Mouthparts. Labrum short and V-shaped bilobed, with two subtruncated teeth on anterior margin. Mandibles falciform, left with two teeth on medial edge. Maxillary palpus elongate, with 3rd segment longest, last slender and aciculate. Labial palpus distinctly slender, with 2nd longest, last slender and aciculate.

Neck. Rather narrow (ca. 0.17 mm), approximately of 1/4 of head width.

Pronotum (Fig. 14-1A). Subrectangular, distinctly elongate (PL to PW ratio 1.4), of same length and width as head. Slightly dilated anteriad, sides sinuate; anterior angles well defined, posterior angles broadly rounded. Integument shiny, extensively covered with oblique microstriae; with two rows of setiferous punctures on each side, admedian row consisting of 4-5 punctures, lateral row with 3-4 punctures straightly arranged; hind angle puncture ca. 1-2 puncture diameters distant from lateral margin. Antesternal plate integrated, not concave; medial longitudinal suture missing, transverse suture on anterior 1/5 fine but visible. Prosternum with demarcated medial longitudinal carina on furcasternum, prosternal process (between anterior legs) triangularly projecting upwards. Mesoventrite extensively covered with transverse microstriae, medial longitudinal carina missing, process of mesoventrite triangularly protruding backwards. Metaventrite rather long, medial longitudinal keel sharp and obvious, with a fine furrow on posterior 1/3 of keel top; process of metaventrite subtruncated.

Elytra (Fig. 14-1A). Subrectangular, distinctly elongate (EL to EW ratio 1.3), of same length and width as pronotum. Humeri well developed, lateral margins widened posteriorly, hind margin convex. Integument shiny and flattened, without microsculpture. Each elytron with three rows of setiferous punctures, along suture, in middle and near lateral margin, other punctures scattered irregularly between them; deflexed portion of each elytron with 2-3 rows of sparse setiferous punctures.

Legs.First four segments of protarsi obviously dilated, heart shaped, bearing extremely dense clothing of white fine hairs ventrally, last tarsomere as long as III–IV combined. Last segment of both meso- and metatarsi longer than that of protarsi and about equal to length of II–IV combined. Tibiae with apical ctenidium, only protibia with 2-3 of subapical ctenidia.

Abdomen.Cylindrical, broadest at segment VI. Terga III–VII shiny, entire surface covered with distinct transverse microstriae, with sparse, scattered, tiny setiferous punctures, but denser laterobasally; each tergite with impunctate basal impression bearing more obvious transverse microstriae. All abdominal sterna shiny, with microstriae and setiferous punctures as those on terga.

Male.Tergite VIII entirely covered with setiferous punctures, except for a narrow medial longitudinal impunctate band; tergite VIII with posterior margin broadly arcuate backwards (Fig. 14A), sternite VIII emarginated (Fig. 14B). Tergite of genital segment (Fig. 14C) symmetrical, with sharply pointed base and subtruncated apex, in situ broadly exposed between pleurites. Pleurites of genital segment symmetrical, connected mediobasally. Sternite (Fig. 14D) asymmetrical, with subtruncated base and more angular right side. Aedeagus (Fig. 14-1D; Fig. 14 E–G) tubular-shaped and small sized, ca. 0.90 mm long; median lobe distinctly elongate, ca. 1/3 of basal bulbus length. Parameres symmetrical and thin, shorter than 1/3 of basal bulbus length. Internal sac (Fig. 14-1E) with well sclerotized structure, tubular-shaped, apical portion with two black and large spines.

Female. Posterior margin of tergite VIII subtruncated, that of sternite VIII subtruncated, and slightly transparent. Genital segment (Fig. 14-1C; Fig. 14H) small, ca. 0.58 mm long. Sternite with subtruncated base. Additional brown transverse sclerite attached to base of genital segment.


China (Yunnan); India, Thailand, Myanmar, Malaysia, Laos, Vietnam.


This species may be distinguished from its congeners by the few number of admedian punctural row of pronotum, the unique internal sac of the aedeagus (Fig. 14G) and genital segment (Fig. 14C, D).