Orsunius immsi ( BERNHAUER 1914) Assing, 2011

Assing, V., 2011, Orsunius gen. nov. from the Oriental region (Coleoptera: Staphylinidae: Paederinae: Medonina), Linzer biologische Beiträge 43 (1), pp. 221-244 : 230-232

Orsunius immsi ( BERNHAUER 1914) , nov.comb. ( Figs 27-40 )

Medon immsi BERNHAUER 1914: 99 f.

Medon rubicundus CAMERON 1918: 73 f.

Sunius immsi : SMETANA (2004).

T y p e m a t e r i a l e x a m i n e d:

M. immsi : Syntypes: 1♀: "Bankatti. Kheri, Forash-by U. P. / For Zool. Coll. Reg. No. / 27.2.1912, A. D. Imms / Immsi Brh. Cotypus / Chicago NHMus, M. Bernhauer Collection / Orsunius immsi (Bernhauer) , det. V. Assing 2010" ( FMNH) ; 1♀: "Bankatti. Kheri or, under Bark of Sal Call [?]. by. [word illegible] / 24-2-1912 / For Zool. Coll. Reg. No. / 5 / Immsi Brh. Typus / Chicago NHMus, M.Bernhauer Collection / Orsunius immsi (Bernhauer) , det. V. Assing 2010" ( FMNH) .

M. rubicundus: Lectotype Ƌ, present designation: "Woodlands, Singapore, Cameron / M. rubicundus / Cotypus. don Cameron. / Chicago NHMus, M.Bernhauer Collection / Lectotypus Ƌ Medon rubicundus Cameron, desig. V. Assing 2010 / Orsunius immsi (Bernhauer) , det. V. Assing 2010" ( FMNH) . Paralectotypes: 1♀: " Singapore, Cameron / rubicundus Cam / rubicundus Cameron. Cotypus / Cotype / Immsi Brnh , det. Bernhauer / Chicago NHMus, M. Bernhauer Collection / Paralectotypus ♀ Medon rubicundus Cameron, desig. V. Assing 2010 / Orsunius immsi (Bernhauer) , det. V. Assing 2010" ( FMNH) ; 1♀: " Woodlands , Singapore. Dr. Cameron. / Wood (rotten) / M. rubicundus Cam. Type / Type / M.Cameron Bequest B.M. 1955-147. / Type / Syntype / Paralectotypus ♀ Medon rubicundus Cameron, desig. V. Assing 2010 / Orsunius immsi (Bernhauer) , det. V. Assing 2010" ( BMNH) ; 1Ƌ [3 legs separated from body]: " Woodlands , Singapore. Dr. Cameron. / Wood (rotten) / Type / M.Cameron Bequest B.M. 1955-147. / Syntype / Paralectotypus Ƌ Medon rubicundus Cameron, desig. V. Assing 2010 / Orsunius immsi (Bernhauer) , det. V. Assing 2010" ( BMNH) ; 1♀: " Woodlands , Singapore. Dr. Cameron. / M. rubicundus Cam. (Cotype) / Immsi Brnh. / M.Cameron Bequest B.M. 1955-147. / Syntype / Paralectotypus ♀ Medon rubicundus Cameron, desig. V. Assing 2010 / Orsunius immsi (Bernhauer) , det. V. Assing 2010" ( BMNH) .

C o m m e n t: The original description of Medon immsi is based on an unspecified number of syntypes from the environs of "Dehra-Dun (Bankatti-Kheri) unter Baumrinden" collected by "A. D. Imms" in February 1912 ( BERNHAUER 1914). Two syntypes were located in the Bernhauer collection. Since both of them are females and evidently conspecific, a lectotype is not designated.

Medon rubicundus was described in an article on the Staphylinidae of Singapore, based on an unspecified number of syntypes collected in "Woodlands, in rotten logs" ( CAMERON 1918). Two syntypes, a male and a female, were found in the Bernhauer collection; one male (disassembled) and two females were located in the collections of the BMNH. The intact male from the Bernhauer collection is designated as the lectotype.

There is some doubt as to whether the previously established synonymy of M. rubicundus and M. immsi is correct. The type specimens of the former are somewhat larger, have a larger head, and the abdomen is of slightly different coloration. However, since no males from the environs of the type locality of M. immsi have become available, it is currently unclear if these differences are an expression of intra- or of interspecific variation. Therefore, the long-standing synonymy ( CAMERON 1931) is maintained for the time being.

R e d e s c r i p t i o n: Small species; body length 3.2-4.3 mm. Habitus as in Fig. 27 . Coloration: head and pronotum reddish; elytra yellowish with the anterior 1/4-1/2 diffusely reddish; abdomen reddish to reddish-brown, with the apex occasionally darker (syntypes of M. immsi ); legs and antennae reddish yellow.

Head of transversely rectangular shape, 1.20-1.25 times as broad as long ( Fig. 28 ); punctation very fine and sparse in median dorsal portion ( Fig. 29 ), somewhat less fine and denser in remainder of dorsal surface; sides of head with long black setae. Eyes large and bulging, approximately as long as postocular portion in dorsal view (slightly longer in syntypes of M. immsi , slightly shorter in syntypes of M. rubicundus). Antennae relatively short and with weakly transverse preapical antennomeres ( Fig. 30 ). Labrum, maxillary palpus, and ligula as in Figs 31-33 . Ventral aspect of head with pronounced microsculpture; gular sutures very narrowly separated ( Fig. 34 ).

Pronotum approximately as broad as (syntypes of M. immsi ), or slightly narrower than (syntypes of M. rubicundus) head, 1.20-1.25 times as broad as long, widest at anterior angles ( Fig. 28 ); lateral margins in dorsal view visible only in posterior half, in anterior half concealed and visible only in lateral view; punctation similar to that of median dorsal portion of head; midline punctate ( Fig. 35 ); lateral margins with long black setae.

Elytra 1.10-1.15 times as long as pronotum ( Fig. 28 ); punctation denser and more distinct than that of pronotum. Hind wings fully developed. Tarsi short; protarsomeres I-IV moderately dilated; metatarsomere I longer than II, but shorter than the combined length of II and III.

Abdomen with fine, dense punctation and with distinct microsculpture; posterior margin of tergite VII with palisade fringe.

Ƌ: sternite VII strongly transverse and with dense, fine, dark pubescence in the middle, posterior margin weakly concave ( Fig. 38 ); sternite VIII with sparse unmodified pubescence, posterior margin broadly and feebly concave ( Fig. 39 ); tergites IX and X as in Fig. 40 ; aedeagus 0.60-0.65 mm long and with symmetric ventral process of distinctive shape ( Figs 36-37 ).

C o m p a r a t i v e n o t e s: From all of its congeners, O. immsi is readily distinguished by the small pronotum (in relation to the head), the concealed anterior half of the pronotal lateral margins, the shape of the pronotum (widest at the anterior angles), the conspicuously fine and sparse punctation of the head and the pronotum, the very narrowly separated gular sutures, as well as by the male sexual characters.

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: Thisspecieshasbeenrecorded from northern India (Uttarranchal Pradesh) and Malaysia (type localities of M. immsi and M. rubicundus, suggesting that, if the type material of both names should be confirmed to be conspecific, Orsunius immsi is widespread in the Oriental and the southern East Palaearctic regions. The types of both M. immsi and M. rubicundus were found associated with dead wood.

Figures

Figs 27-37: Orsunius immsi (BERNHAUER) (lectotype of Medon rubicundus CAMERON): (27) habitus; (28) forebody; (29) median dorsal portion of head; (30) antenna; (31) labrum; (32) maxillary palpus; (33) ligula; (34) ventral aspect of head; (35) median dorsal portion of pronotum; (36- 37) aedeagus in lateral and in ventral view. Scale bars: 27: 1.0 mm; 28, 30: 0.5 mm; 29, 31-32, 34- 37: 0.2 mm; 33: 0.1 mm.

Figs 38-40: Orsunius immsi (BERNHAUER) (lectotype of Medon rubicundus CAMERON): (38) posterior median portion of male sternite VII; (39) male sternite VIII; (40) male abdominal segments IX-X in dorsal view. Scale bar: 0.2 mm.