Metolinus xizangensis Zhou & Zhou

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 : 55-57

1. Metolinus xizangensis Zhou & Zhou sp. n. Fig. 10 A–HFig. 10-1 A–E

Type material.

Holotype: male, CHINA: Xizang: Cayu co.: Shangcayu (E 97.0994, N 28.7131), 1960 m, 21.VIII.2005, Wu Jie & Wang Xuejian collected (IZ-CAS); Paratypes: CHINA: Xizang: 6 males, 6 females, same data as holotype; 2 males, 1 female, same locality as holotype, 2000 m, 7.VIII.2005, Wu Jie collected (IZ-CAS).

Description.

Measurement. BL=7.9 mm, FL=3.8 mm, HL=1.2 mm, HW=0.93 mm, PL=1.3 mm, PW=0.90 mm, EL=1.3 mm, EW=1.1 mm.

Body nearly compressed and medium sized. Head, pronotum, mesoscutellum and elytra entirely dark brown. Abdomen dark brown, segment II and genital segments paler. Legs brown except femora obviously darker. Antennae entirely brown. Maxillary palpi and labial palpi light brown.

Head(Fig. 10-1A). Subrectangular (HL to HW ratio 1.3), tempora (behind eyes) slightly widened posteriorly, posterior angles rounded. Dorsal integument shiny, with extensive microsculpture composed of a mixture of transverse microstriae and polygonal reticulum, and with sparse, scattered with setiferous punctures of medium size, distance between punctures ca. 2 puncture diameters. With pair of frontal puncture on epistoma, 2 antennal punctures near antennal insertion, ocular puncture near medial margin of eye (ca. 3-4 puncture diameters to eye), temporal puncture at posterior 1/5 and occipital puncture at lateral 1/3; deflexed portion of tempora with same setiferous punctures and microstriae as on dorsal integument. Frontal furrows superficial and short, not longer than 1/2 of eye length. Ocular furrows of medium length, equal to eye length. Eye of medium size, nearly 1/3 of temple length (eye: temple = 0.23:0.68 mm), 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. 0.32 mm, obviously wider than that from antenna to eye (ca. 0.26 mm). Ventral integument shiny, with polygonal reticulum, and with setiferous punctures as on dorsal integument, but obviously denser laterad. Mentum with a pair of setae inserted at anterior angle in addition to other irregularly scattered setae, submentum with 2 pairs of setae. Gular sutures fused at middle, and not separated at base of occiput. Gular plate devoid of punctures, with distinct transverse microstriae.

Antennae (Fig. 10-1B). Scape stout, thickened apically, longer than three subsequent antennomeres combined, ca. 0.45 mm; 2nd elongate, ca. 0.14 mm, distinctly longer than 3rd; 3rd globular, ca. 0.090 mm; 4th and 5th subequal, ca. 0.080 mm; last antennomere of medium length, ca. 0.15 mm, subequal to preceding 2 antennomeres combined.

Mouthparts. Labrum transverse and V-shaped bilobed, two lateral teeth subtruncated 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. 0.24 mm), approximately of 1/4 of head width.

Pronotum(Fig. 10-1A).Subrectangular, distinctly elongate (PL to PW ratio 1.4), of same length and width as head. Slightly widened anteriad, lateral margins concavely 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 7-9 punctures and lateral row of 6-8 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 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 demarcated, process of mesoventrite triangularly protruding backwards. Metaventrite rather long, medial longitudinal keel sharp and obvious, without a fine furrow on posterior 1/3 of keel top; process of metaventrite subtruncated.

Elytra(Fig. 10-1A).Subrectangular, distinctly elongate (EL to EW ratio 1.2), of same length as pronotum, but obviously wider. Humeri well developed, lateral margins subparallel or slightly widened posteriorly, hind margin subtruncated. Integument shiny and flattened, without microsculpture, and with setiferous punctures arranged in several rows (more than 3 rows) on each elytron; deflexed portion of each elytron with 2-3 rows of sparse setiferous puncture s.

Legs(Fig. 10-1C). 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 rows of subapical ctenidia.

Abdomen.Cylindrical, broadest at segment VI. Terga III–VII shiny, entire surface covered with distinct transverse microstriae, sparsely scattered with dot-like 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 a narrow medial longitudinal impunctate band; posterior margins of tergite VIII and sternite VIII both arcuately protruding backwards (Fig. 10A, B). Tergite of genital segment symmetrical and small, with sharp base and subtruncated apex (Fig. 10C), in situ broadly exposed between pleurites. Pleurites of genital segment symmetrical, connected mediobasally. Sternite asymmetrical, with rounded base and more angular left side (Fig. 10D). Aedeagus pear-shaped and medium sized (Fig. 10-1E; Fig. 10 E–G), basal bulbus ca. 1.50 mm long; median lobe triangular and long, ca. 1/3 of basal bulbus length. Parameres symmetrical and thin, ca. 1/3 of basal bulbus length. Internal sac with a cylindrical and spiral solid structure, of black color but base paler.

Female. Posterior margin of tergite VIII and sternite VIII broadly arcuate backwards. Genital segment medium sized (Fig. 10-1D; Fig. 10H), ca. 0.86 mm long. Sternite with subtruncated base. No additional sclerites attached on base of genital segment, except some membranous structures.

Distribution.

China (Xizang).

Etymology.

The specific epithet is the Chinese name (Pin-Yin) of the type locality.

Remarks.

This species could be distinguished from its congeners by microsculpture on head, the shape of the male genital segment (Fig. 10C, D) and the internal sac of the aedeagus (Fig. 10G).