Marcepania halva, Jałoszyński, 2020

Jałoszyński, Paweł, 2020, Three new species of Marcepania Jałoszyński (Coleoptera: Staphylinidae Scydmaeninae), Zootaxa 4852 (2), pp. 223-230 : 224-226

Marcepania halva sp. n.

( Figs 1 , 4–9 )

Type material. Holotype: INDONESIA (North Sumatra Province): ♂, two labels: “ SUMATRA: N Sum. / 7 km N Brastagi / 1500 m, 2.XII.1989 / Agosti, Löbl / Burckhardt # 28a” [white, printed], “ MARCEPANIA / halva m. / P. Jałoszyński, 2020 / HOLOTYPUS ” [red, printed] ( MHNG) . Paratypes: 1 disarticulated female mounted in Canada balsam and 3 dry-mounted specimen of unknown sex, same data as for holotype (cPJ, MHNG) .

Diagnosis. Body relatively stout, EI approximately 1.3, and large (BL slightly above 1 mm); head, pronotum and elytra with distinct, dense punctures; aedeagus elongate and subtrapezoidal with oblique distal margin; endophallus with a pair of well demarcated elongate structures, only slightly darker than surrounding areas; parameres much longer than median lobe, each with two conspicuously long apical setae.

Description. Body of male ( Fig. 1 ) elongate and slender, moderately convex, light brown, covered with yellowish setae; BL 1.08 mm.

Head ( Figs 1 , 4 ) broadest at moderately large, weakly convex, oval and coarsely faceted eyes, HL 0.10 mm, HW 0.25 mm; vertex and posterior region of frons confluent and weakly convex; anterior portion of frons flattened; supraantennal tubercles barely marked; frons and vertex covered with dense and distinct but shallow punctures; setae sparse and short, suberect.Antennae ( Figs 1 , 4 ) short, AnL 0.43 mm; antennomeres 1–2 strongly elongate; 4 slightly transverse, 5–7 each elongate; 8 and 9 each almost as long as broad, 10 indistinctly transverse, 11 much shorter than 9–10, about 1.8 × as long as broad, with truncate apex.

Prothorax ( Figs 1 , 5 ) nearly semi-oval, broadest slightly in front of middle; PL 0.35 mm, PW 0.43 mm.Anterior margin rounded; lateral margins strongly and nearly evenly rounded in anterior half, nearly straight and weakly convergent posterad in posterior half; hind corners weakly obtuse-angled; posterior margin shallowly bisinuate; lateral ante-basal impressions small and shallow but with relatively sharp margins. Punctures on disc distinct, relatively sharply marked and dense, those near middle separated by spaces slightly shorter than puncture diameters; setae sparse, short, suberect.

Elytra ( Figs 1 , 7 ) together oval, broadest near anterior third; EL 0.63 mm, EW 0.48 mm, EI 1.32; apices broadly, separately rounded; punctures similar to those on pronotum but denser, partly arranged into irregular longitudinal rows; setae short, sparse, suberect.

Legs short, robust; unmodified.

Aedeagus ( Figs 8–9 ) moderately stout; AeL 0.15 mm; median lobe in ventral view elongate subtrapezoidal with oblique distal margin; endophallic structures weakly sclerotized, with pair of elongate fusiform components only slightly darker than surrounding areas; parameres conspicuously long, each with two long apical setae.

Distribution. Northern Sumatra ( Fig. 14 ).

Etymology. The name halva (a noun in apposition) refers to the Middle East sweet confection (as fitting well the genus name that is derived from marzipan).

Remarks. This species has the largest and most convex adults; this is the only known Marcepania whose adults exceed 1 mm in length. The unusually convex body prompted detailed morphological examination to confirm that this is indeed a Marcepania and not an unknown genus. Structures of a disarticulated female ( Figs 4–7 ) do not differ in any detail from those known in previously examined species ( Jałoszyński 2013); M. halva has asymmetrical mandibles, the right one with pre-apical tooth ( Fig. 4 ; pat, lacking in the left one), button-shaped maxillary palpomere 4 ( Fig. 4 ; mxp4), gradually thickened antennae, open procoxal cavities ( Fig. 5 ; pcxc), complete notosternal sutures ( Fig. 5 ; nss; poorly visible in a photograph, but confirmed as complete under microscope), narrow inner (i.e., adcoxal) portions of hypomera ( Fig. 5 ; ihy), a massive mesoventral intercoxal process ( Fig. 6 ; msvp) clearly separating mesocoxae, its posterior margin bearing a long and narrow median longitudinal carina ( Fig. 6 ; mlc) running posteriorly, lateral metaventral carinae ( Fig. 6 ; lmvc) and lateral metaventral foveae ( Fig. 6 ; lmvf), broadly separated metacoxae, a transverse mesoscutum ( Fig. 7 ; sc2) and mesoscutellum ( Fig. 7 ; scl2) with a distinct scutoscutellar suture ( Fig. 7 ; sss), and well-marked humeral denticles ( Fig. 7 ; hd). Together with a weakly sclerotized, plate-shaped, simple aedeagus with slender parameres, this set of characters agrees with that given in the diagnosis of Marcepa- nia ( Jałoszyński 2013). An additional character was found in M. halva (and, less pronounced, in the two remaining newly described species), i.e., setiferous punctures on elytra partly arranged in longitudinal rows. This feature is poorly visible in small specimens, and it may occur in all Marcepania species, but only in the large-bodied M. halva it is distinct enough to be easily noticed under a stereomicroscope. The rows of setae and setiferous punctures are better visible in transparent mounts of disarticulated elytra.

The aedeagus of M. halva is most similar to that of M. semengohensis Jałoszyński, 2013 , and M. princesa Jałoszyński, 2019 . In addition to proportionally much longer parameres and different endophallic structures, M. halva differs from these two species in external characters: the male of the newly described species is distinctly stouter, with EI 1.32, versus 1.40–1.47 in M. semengohensis and 1.52 in M. princesa . Together with M. krowka described below, this is the first record of the occurrence of Marcepania on Sumatra.

Figures

FIGURE 14. Distribution of Marcepania species.

FIGURES 1–3. Dorsal habitus of Marcepania halva sp. n. (1), M. krowka sp. n. (2), and M. daifuku sp. n. (3).

FIGURES 4–7. Morphological structures of Marcepania halva sp. n. with structures important for genus identification indicated. Head in ventral view (4); prothorax in ventral view (5); pterothorax in ventral view (6); elytral base with meso- and metanotum in dorsal view (7). Abbreviations: hd, humeral denticle; ihy, inner portion of hypomeron; lmvc, lateral metaventral carina; lmvf, lateral metaventral fovea; mlc, median longitudinal carina; msvp, mesoventral intercoxal process; mxp4, maxillary palpomere 4; nss, notosternal suture; pat, pre-apical tooth; pcxc, procoxal cavity; sc2, mesoscutum; scl2, mesoscutellum; sss, scutoscutellar suture.

FIGURES 8–13. Aedeagus in ventral view. Marcepania halva sp. n. (8–9), M. krowka sp. n. (10–11; one paramere broken off), and M. daifuku sp. n. (12–13; 12 includes also a fragment of abdominal segment, omitted in 13).