Metolinus shanicus Bordoni, 2002

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 : 61-63

4. Metolinus shanicus Bordoni, 2002 Fig. 13 A–HFig. 13-1 A–E

Bordoni 2002: 375 (Type locality: Yunnan, Gaoligongshan Mts., 90 km W of Baoshan); Bordoni 2007: 71 ( Metolinus ; catalog)

Material examined.

2 males, 4 females, CHINA: Yunnan: Jingdong co.: Ailaoshan Field Station (E 98.2974, N 25.1119), 2486 m, 20.IX.2010, Zhou Yulingzi collected (IZ-CAS); 1 female, same locality as above, 21.IX.2010, Zhang Xi collected (IZ-CAS).

Description.

Measurement. BL=4.7 mm, FL=2.7 mm, HL= 0.74 mm, HW=0.66 mm, PL=0.87 mm, PW=0.60 mm, EL=0.99 mm, EW=0.78 mm.

Body small and nearly compressed. Head dark brown; pronotum, mesoscutellum, elytra and abdomen brown, except humeral portion (anterior 1/3 of elytra), posterior half of abdominal segment VII and entire VIII ochre. Legs entirely testaceous. Antennae, maxillary palpi and labial palpi castaneous.

Head (Fig. 13-1A). Subquadrate (HL to HW ratio 1.1), tempora (behind eyes) subparallel or 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. 4-5 puncture diameters. On each side symmetrically with frontal puncture on the epistoma, 2 antennal punctures near antennal insertion, ocular puncture near inner side of eye (ca. 3-4 puncture diameters from eye), temporal puncture at posterior 1/4 and occipital puncture at lateral 1/3; deflexed portion of tempora with same setiferous punctur es and microstriae as on dorsal integument. Frontal furrows of medium length, ca. 2/3 of eye length, slightly curved and extending backward to same level of eye midlength. Ocular furrows of medium length, as long as eye length. Eye of medium size, nearly 1/3 of temple length (eye: temple =0.15:0.45 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 that from antenna to eyes (ca. 0.15 mm). Ventral integument shiny, with same microstriae and setiferous punctures as dorsal integument, except punctures deeper. Mentum with two pairs of setae inserted at anterior angles in addition to other irregularly scattered setae, submentum with 2 pairs of setae. Gular sutures fused at middle, not separated at base of occiput. Gular plate devoid of punctures, but with distinct transverse microstriae.

Antennae (Fig. 13-1B). Scape stout, thickened apically, longer than three subsequent antennomeres combined, ca. 0.33 mm; 2nd elongate, ca. 0.12 mm, distinctly longer than 3rd; 3rd globular, ca. 0.075 mm; 4th and 5th subequal, ca. 0.06 mm; last antennomere proportionately long, ca. 0.12 mm, subequal to preceding 3 antennomeres combined.

Mouthparts. Labrum transverse and V-shaped bilobed, with two subtruncated teeth on anterior margin. Mandibles falciform, left one 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. 13-1A).Subrectangular, distinctly elongate (PL to PW ratio 1.5), obviously longer than head but of same width as head. Slightly widened anteriad, lateral margins substraight; anterior angles well defined, posterior angles broadly rounded. Integument shiny, extensively covered with obliquely microstriae; with two rows of setiferous punctures on each side, admedian row consisting of 5-7 punctures, lateral row of 4-5 punctures obliquely arranged; hind angle puncture ca. 1-2 puncture diameters distant from lateral margin. Antesternal plate integrated and symmetrically shallowly concave medially; medial longitudinal suture missing, transverse suture at anterior 1/5 fine but observable. 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 demarcated, process of mesoventrite triangularly protruding backwards. Metaventrite rather long, medial longitudinal keel sharp and obvious, without a fine furrow on keel top; process of metaventrite subtruncated.

Elytra (Fig. 13-1A).Subrectangular, distinctly elongate (EL to EW ratio 1.3), obviously longer and wider than pronotum. Humeri well developed, lateral margins subparallel, slightly widened posteriorly, hind margin subtruncated. Integument shiny and flattened, without microsculpture. Each elytron with three rows of setiferous punctures, along suture, in middle and near lateral margin, additional 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 meso- and metatarsi longer than that of protarsi and about equal to length of II–IV combined. Tibia with apical ctenidium, only protibia with 2-3 rows of subapical ctenidia.

Abdomen. Cylindrical, broadest at segment VI. Terga III–VII shiny, entire surface covered with distinct transverse microstriae, with sparse, scattered, round 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 VIIIentirely covered with setiferous punctures, except a narrow medial longitudinal impunctate band; posterior margin of tergite VIII triangularly extended (Fig. 13A), that of sternite VIII triangularly emarginated (Fig. 13B). Tergite of genital segment (Fig. 13C) symmetrical, with sharp base and round apex, in situ broadly exposed between pleurites. Pleurites of genital segment symmetrical, connected mediobasally. Sternite (Fig. 13D) asymmetrical, with subtruncated base and more angular right side. Aedeagus (Fig. 13-1D; Fig. 13 E–G) elliptical and medium sized, basal bulbus ca. 1.04 mm long; median lobe distinctly elongate, ca. 1/3 of basal bulbus length. Parameres symmetrical and of medium length, ca. 1/3 of basal bulbus length, thin and curved. Internal sac (Fig. 13-1E) with well sclerotized structure, some large spines on base, some small spines spirally arranged in middle, a long and thin flagellum extending out and intertwining right paramere in dorsal view.

Female. Posterior margin of tergite VIII and sternite VIII broadly arcuate backwards. Genital segment (Fig. 13-1C; Fig. 13H) small, ca. 0.40 mm long. Sternite with subtruncated base. Additional triangular-shaped sclerite attached to base of genital segment and folded by itself (Fig. 13-1C).

Distribution.

China (Yunnan).

Remarks.

This species may be distinguished from its congeners by the bicolorous elytra, the unique internal sac of aedeagus (Fig. 13G) and genital segment (Fig. 13C, D). However, the shape of the male tergite VIII of the specimens reported here slightly differs from the illustration given by Bordoni (2002: 374) which might reflect some degree of intraspecific variation.