Medhiama formosana Bordoni, 2002

Zhou, Yu-Lingzi & Zhou, Hong-Zhang, 2012, Taxonomy of the genus Medhiama Bordoni, 2002 (Coleoptera: Staphylinidae, Staphylininae, Xantholinini) with descriptions of three new species, Zootaxa 3478, pp. 169-191 : 180-181

4. Medhiama formosana Bordoni, 2002

( Fig. 6 A, B)

Bordoni, 2002: 670 (Type locality: China, Taiwan, near Tungpu, Nantou-Hsien; 2600 m); Bordoni, 2007b: 71 (catalog); Bordoni, 2011: 27 ( Taiwan).

Material examined: female, with labels as follows: “ Paratypus, Medhiama formosana n. sp., Bordoni det. 1997”/ “(ALISHAN), Chiai-Hsien, Taiwan (2300 m), ‘ Aug. 8th, 1978 ’, Y. Shibata leg.”; female, with labels as follows: “ Paratypus, Medhiama formosana n. sp., Bordoni det. 1997”/ “(Near TUNGPU), Nantou-Hsien, TAIWAN (2600 m), ‘ Aug. 17th, 1973 ’, Coll. S. Nakamura” (CYS).

Description. Female. Measurement. BL= 5.78 mm, FL= 3.40 mm, HL= 1.08 mm, HW= 0.82 mm, PL= 1.18 mm, PW= 0.72 mm, EL= 1.05 mm, EW= 0.97 mm.

Body nearly cylindrical and medium sized. Entirely brown, except head and elytra slightly darker in color.

Head. Not very long (HL to HW ratio 1.33), tempora substraight or slightly widened, posterior angles widely rounded. Dorsal integument entirely bearing mixed and distinct microsculpture composed of isodiametric microsculpture and transverse microstriae, and extensively distributed deep and medium punctures, puncture intervals less than puncture diameter. Median longitudinal region impunctate, width equals to 2–3 puncture diameters; frontal region bearing distinct polygonal reticulum, also with 3 pairs of tiny punctures and 2 irregular larger punctures. Each side of cranium with anterolateral puncture near antennal insertion, midlateral puncture relatively near dorsal margin of eye (3–4 puncture diameters to eye), temporal puncture rather near lateral margin (at lateral 1/6) and occipital puncture rather near posterior margin (at posterior 1/6). Frontal furrows deep and long, convergent backwards; anteocular furrows indistinct, scarcely observable. Eye of medium sized and slightly protruding, diameter slightly longer than 1/4 of temporal length (eye: tempora = 0.19: 0.72 mm). Epistoma relatively wide, subrectangular and flat, with a pair of tiny punctures. Distance between antennal insertions 0.27 mm, longer than distance from antenna to eye (0.19 mm).

Antennae. Scape stout, thickened apically, much longer than three subsequent antennomeres combined, 0.44 mm; antennomere II slightly elongate or subglobular, 0.11 mm; III elongate, of same length as II; IV and V subequal in length, 0.08 mm; last antennomere of medium length, 0.19 mm, subequal to two preceding antennomeres combined.

Mouthparts. Labrum bilobed, with a median longitudinal groove. Maxillary palpus elongate, segment III longest, last segment slender and obconical and shorter than the penultimate. Labial palpus distinctly slender, last segment longest.

Neck. Medium width (0.30 mm), slightly longer than 1/3 of head width, with a transverse substraight ridge on anterior 1/3.

Pronotum. Subrectangular, rather elongate (PL to PW ratio 1.63), of same length as head, but narrower. Widest at anterior 1/6, narrowest at posterior 1/4. Anterior angles dilated and protruding, lateral margins slightly sinuate from middle, posterior angles rounded. Integument bearing microstriae, and a pair of admedian row of 13–16 smaller punctures. Areas outside admedian rows with additional, irregular, sparsely set punctures.

Mesoscutellum. Shiny, extensively bearing polygonal reticulum and with a pair of tiny punctures near apex.

Elytra. Subrectangular (EL to EW ratio 1.1), slightly shorter but distinctly wider than pronotum. Humeri well developed, lateral margins widened posteriorly, hind margin rounded. Integument shiny, without microsculpture; each side symmetrically with regular rows of punctures, interspaces between rows 1–2 puncture diameters; deflexed portion of each elytron with 3–4 rows of punctures.

Legs. First four segments of protarsi and metatarsi stout, not dilated, those of mesotarsi relatively slender; each last segment as long as the II–IV combined. Protibia with apical ctenidium and subapical ctenidia, meso- and metatibia only with apical ctenidium.

Abdomen. Cylindrical, broadest at segment VII. Tergites III–VII slightly shiny, surface entirely covered with a distinct mixture of extensive microstriae and polygonal reticulum; punctures small, interspace between them 2–3 puncture diameters, but much denser on tergite VII. Each tergite without distinct basal impression near anterior margin. Surface between two basal transverse carinae of tergites III–VII bearing distinct polygonal reticulum. All abdominal sternites slightly shiny, with microstriae and setiferous punctures as those on tergites. Sternite VIII quite broad and with substraight lateral margins, and posterior margin sharply protruding posteriorly ( Fig. 6 B). Genital segment with a small pair of subtriangular supplementary sclerites, and a distinctly elongate sternite with slightly sinuate anterior margin ( Fig. 6 A).

Distribution. China ( Taiwan).

Remarks. This species can be easily distinguished from its congeners by the following characteristic combination: in male by distinctly long parameres, simple, non-sclerotized internal sac; in female by relatively shorter head, narrower pronotum, more protruding anterior angles of pronotum, quite broad sternite VIII and a distinctly elongate sternite of female genital segment.

Figures

FIGURE 6. Medhiama formosana Bordoni: A. female genital segment; B. female sternite VIII. Scale bars 0.15 mm.