Medon sundaicus, Assing, 2018

Assing, Volker, 2018, A revision of Medon. XI. Five new species, additional records, and the first confirmed records from the Oriental region (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology (Beitr. Entomol.) 68 (1), pp. 69-81 : 75-77

Medon sundaicus spec. nov.

urn:lsid:zoobank.org:act:5009E115-85F9-441E-9348-2FFCEEC75102

( Figs 13–21 )

Type material: Holotype ♂: “ Indonesia, Jawa Barat, Mount Halimun , 19–25.VIII.2009, leg. Majer / Holotypus ♂ Medon sundaicus sp. n. det. V. Assing 2017” (cAss) . Paratypes: 13 exs.: “ SULAWESI TENGAH: Solato R., Taronggo , 1°45'S – 121°40'E, 27–30.iii.1980 / sieving / M.J.D. Brendell, B.M. 1980-280” ( BMNH, cAss) ; 1 ex.: “ SULAWESI TENGAH: Nr. Kolonodale, Gililana village , 1°55'S – 121°22'E. 7–8.ii.1980 / rotting fruit / M.J.D. Brendell, B.M. 1980-280” ( BMNH) ; 1 ♀: “ INDONESIA: SULAWESI UTARA, Dumoga-Bone N.P., February 1985. / Plot B, ca 300 m, Lowland forest / Flight interception trap / R.Ent.Soc.Lond., Project Wallace, B.M. 1985- 10” ( BMNH) ; 1 ♀: same data, but “Plot A, ca 200 m ” ( BMNH) ; 1 ♀: “ INDONESIA: SULAWESI UTARA, Dumoga-Bone N.P., 1985. / ‘ Edwards’ Camp, Lowland forest , 664 m, 26.iv.–4.vi. / Malaise trap / R.Ent.Soc. Lond., Project Wallace, B.M. 1985-10” ( BMNH) .

Additional material: 1 ♂ [in poor condition]: “ Thailand, Ban Sai Yok, 9.III.82, Rougemont” (cRou).

Comment: The above male from Thailand is not included in the type series. Its primary and secondary sexual characters ( Figs 15, 17, 20–21 ) are practically identical to those of the males from Java and Sulawesi, but the microsculpture of the head is much less pronounced. Additional material from Thailand or adjacent regions is required to assess whether the populations from the Sunda Islands and Thailand are conspecific.

Etymology: The specific epithet (adjective) alludes to the fact that this species is at present reliably known only from two of the Great Sunda Islands.

Description: Body length 3.0–4.0 mm; length of forebody 1.6–1.9 mm. Coloration: head brown to blackish-brown; pronotum reddish to dark-brown; elytra pale reddish, posteriorly often with an extensive dark spot of somewhat variable size and shape posteriorly, this spot not reaching suture, posterior margins, and humeral portion; abdomen reddish to reddish-brown, usually with at least the middle of tergites VI and VII somewhat infuscate; legs yellowish; antennae reddish.

Head ( Fig. 13 ) weakly transverse, 1.05–1.10 times as broad as long, and with marked posterior angles; punctation very fine and moderately dense; interstices with distinct fine microreticulation. Eyes large and moderately convex, slightly shorter than postocular region in dorsal view.

Pronotum ( Fig. 13 ) approximately 1.1 times as broad as long and about as broad as head, or slightly broader; punctation and microsculpture similar to those of head, or slightly more pronounced.

Elytra ( Fig. 13 ) slightly shorter than pronotum; punctation dense and fine, but much more distinct than that of head and pronotum; interstices without microsculpture. Hind wings fully developed. Metatarsomere I slightly longer than II, distinctly shorter than the combined length of II and III.

Abdomen slightly narrower than elytra; punctation fine, very dense on anterior and somewhat less dense on posterior tergites; interstices with pronounced microreticulation; posterior margin of tergite VII with palisade fringe.

♂: sternite VII ( Figs 14–15 ) moderately transverse, posterior margin with broad and pronounced concavity, on either side with a comb of 5–6 palisade setae; sternite VIII ( Figs 16–17 ) with a rather large posterior excision of subtriangular shape; aedeagus ( Figs 18–21 ) 0.42–0.46 mm long and slender; internal sac with a dark median structure.

Comparative notes: Based on the derived shapes and chaetotaxy of the male sternites VII–VIII and on the morphology of the aedeagus, M. sundaicus belongs to the M. ferrugineus group (see ASSING 2013). It is distinguished from other species of this group by the shape and chaetotaxy of the male sternite VII, and by the shape of the aedeagus. In addition, it is characterized by rather small size, as well as the distinct microsculpture and fine punctation of the forebody.

Distribution and natural history: Medon sundaicus represents the first confirmed representative of the genus from the Oriental region and Indonesia. The record from Thailand should be considered tentative. The type specimens were collected in the type locality in Jawa Barat and in three localities in Sulawesi Tengah and Sulawesi Utara, northern Sulawesi, by sifting forest litter, as well as with flight interception and Malaise traps. One specimen was collected from rotting fruit. Part of the type material from Sulawesi is slightly teneral.

Figures

Figs 13–25: Medon sundaicus spec. nov. (13–21, 15, 17, 20–21: non-type male from Thailand) and M. sabahicus spec. nov. (22–25): forebody (13); male sternite VII (14–15, 22); male sternite VIII (16–17, 23); median lobe of aedeagus in lateral and in ventral view (18–21, 24–25). Scale bars: 13: 0.5 mm; 14–25: 0.2 mm.