Herniosina erymantha, Rohacek, Jindrich, 2016

Rohacek, Jindrich, 2016, Herniosina Rohacek: revised concept, two new species, new key and atlas of male and female terminalia (Diptera, Sphaeroceridae), ZooKeys 609, pp. 69-106 : 77-82

Taxon classification Animalia Diptera Sphaeroceridae

Herniosina erymantha sp. n. Figs 14, 15-19, 20-26

Type material.

Holotype ♂ labelled: "GREECE: NW Peloponnese: Alepochori 0.5 km SE 37°58'57"N, 21°48'10"E ", "590 m, 27.5.2015, sifting leaves under Platanus , J. Roháček leg.", "Holotypus ♂ Herniosina erymantha sp. n., J. Roháček det. 2016" (red label). The specimen is dry-mounted on pinned triangular card, with left wing and abdomen detached, genitalia dissected and all removed parts preserved in glycerine in coalesced plastic tube pinned below the specimen (SMOC).

Etymology.

The name of the new species is an adjective derived from the Erimanthos (= Lat. Erymanthos) Mts inasmuch as its type locality is situated in the western part of this montane range.

Description.

Male. Total body length 1.79 mm; general colour blackish brown with relatively sparse dark greyish brown microtomentum. Head blackish brown to brown. Frons largely blackish brown, brownish only at anterior margin, rather sparsely microtomentose. Occiput blackish brown and dark greyish brown microtomentose. Orbits, interfrontalia (poorly delimited) and ocellar triangle also greyish brown (not densely) microtomentose and duller than rest of frons; frontal triangle comparatively wide and shining. Cephalic chaetotaxy: pvt absent, only minute adpressed postocellar setulae behind ocellar triangle; occe and occi subequal and less than half length of vte; vti longest among frontal setae, vte and oc slightly shorter than vti; 2 strongly exclinate ors, both distinctly shorter than oc; only 3 relatively short ifr, the middle pair longest; 3-4 very minute ads inside and below ors; g weak, not longer than anterior peristomal setula; vi about as long as vti. Frontal lunule short, wide, similarly brown as anterior margin of frons. Face with cavities below antennae dark brown, rather shining; medial carina slightly elevated but distinct. Gena high, reddish only anteriorly, otherwise blackish brown, sparsely greyish microtomentose. Eye relatively small; its longest diameter about 2.2 times as long as smallest genal height. Antenna blackish brown, relatively long; its 3rd segment distinctly tapered apically both in dorsal and lateral view. Arista long, about 3.8 times as long as antenna, relatively long ciliate.

Thorax dark brown to blackish, mesonotum subshining due sparser microtomentum, pleuron lighter and dull. Suturae between pleural sclerites paler brown. Scutellum relatively large and long, rounded triangular. Thoracic chaetotaxy: 2 hu but internal reduced to microseta; 2 postsutural dc, anterior short and weak (only twice longer than ac microsetae), posterior strong but slightly shorter than basal sc; 8-10 rows of ac microsetae on suture; medial prescutellar ac pair somewhat prolonged; 2 strong sc, basal slightly longer than scutellum, apical about 1.6 times as long as basal; 2 stpl but anterior reduced to minute hair-like setula.

Legs dark brown, coxae, trochanters, knees and tarsi pale brown to ochreous. f1 with relatively sparse setae in posterodorsal and posteroventral rows. f2 with a row of curved but relatively short ventral setae in basal half (Fig. 18); t2 ventrally with a long row of small dense spines and reduced va seta (shorter than anteroapical seta), see Fig. 18; dorsal chaetotaxy of t2 as in congeners but posterodorsal seta in apical fourth somewhat shorter (Fig. 16). t2: mt2 = 1.84.

Wing (Fig. 14) with pale brownish membrane and ochreous to dark brown veins. C hardly produced beyond apex of R4+5. R2+3 slightly sinuate but apically distinctly upcurved to C; R4+5 sinuate and its apical half almost straight. Discal cell (dm) relatively short and distally less tapered than in most relatives, with small process of M beyond dm-cu; posterior outer corner of dm not rounded but obtuse-angled. A1 sinuate; anal lobe well developed; alula narrow but not acute. Wing measurements: length 1.87 mm, width 0.77 mm, C-index = 0.95, rm\dm-cu: dm-cu = 2.62. Haltere with ochreous stem and dark brown knob.

Abdomen blackish brown, with some sclerites brown. Preabdominal terga large, shining blackish brown, with only scarce greyish microtomentum, sparsely and shortly setulose. T4 longer than T3; T5 enlarged but less than that of Herniosina bequaerti , postabdomen strongly down-curved (Fig. 15). Preabdominal sterna as in Figs 15, 17: S1+2 strongly bulging (Fig. 15) and anteromedially narrowly desclerotized (Fig. 17); S3 and S4 deeply anteriorly emarginate due to large lateral lobes (Fig. 17), with distinctive pigmentation; S1+2, S3 and S4 with sparse setae at posterior margins, with only medial (in S4 submedial) pair longer. S5 (Fig. 19) reduced and transversely strip-shaped, with setose lateral parts as in relatives but with distinctive dark medial part provided with a flattened (in lateral view knob-like, Fig. 15) and distally forked process having 2 setulae on each lobe of its digitiform terminal part (Fig. 19). S6 and S7 fused to form a complex sclerite on left side of postabdomen, narrow ventrally and dorsally but dilated laterally (Fig. 15) as in congeners. S8 shorter and more tapered, with a slit left laterally and a few setae.

Genitalia. Epandrium (Figs 20, 21) of medium length but comparatively wide and more angular dorsolaterally (see Fig. 21) than those of relatives, and with a group of longer and stronger setae laterally and lateroventrally (posterior seta longest and most robust) but dorsolaterally without longer seta. Anal fissure slightly wider than high (Fig. 21), subcircular. Cerci fused with epandrium, posteroventrally projecting in 2 processes, one (more anterior) robust, long (about as long as gonostylus) and distally somewhat thickened and bearing 1 long seta in addition to a number of setulae, the other (more medial) small, elongately conical and simple (Figs 20, 21). Medandrium small (low), reduced but connected by long internal arms with gonostyli (Fig. 21), posteromedially fused with cerci. Hypandrium with very long and slender anteromedial rod-like apodeme (Fig. 20). Gonostylus (Figs 20-23) most resembling that of Herniosina bequaerti but ventrally simple (not emarginate in lateral view), with longer anteroven tral seta, and with long, very slender, curved and apically lancet-shape dorsal internal process (cf. Fig. 22). Aedeagal complex (Figs 24-26) with long phallapodeme (as in Herniosina bequaerti ) but having distinctly lower dorsal keel. Aedeagus also somewhat similar to that of Herniosina bequaerti but with funnel-shaped apex of distiphallus more robust, its lateral lobes and unpaired ventral process markedly longer and its postgonite more slender, with curved, slender and terminally blunt apex. Phallophore closely resembling that that of Herniosina bequaerti , anteriorly rod-like but dorsoventrally flattened, posteriorly projecting ventrally and hence epiphallus-like. Ejaculatory apodeme not observed.

Female unknown.

Discussion.

Herniosina erymantha sp. n. is only known from the male holotype and, consequently, for the evaluation of its relationships the female characters cannot be used. However, based on the male terminalia the species is a distinctive member of Herniosina unmistakeably recognizable from any other known congener. It differs from all relatives by the flattened, distinctively forked medial process of S5 (Fig. 19), broad epandrium with strikingly rectangular dorsolateral corners without dorsolateral long seta and with broad (wider than high) anal fissure (Fig. 21), relatively simple sub-oblong gonostylus (Fig. 23) with very slender and long internal process (Fig. 22), distinctive cercus with long and robust, distally somewhat dilated but laterally flattened lateral process combined with short medial ones (Figs 20, 21) and characteristic postgonite (Fig. 24).

Judging from the construction of the male abdomen and male genitalia, Herniosina erymantha seems to be related to Herniosina bequaerti and Herniosina horrida sharing with them the following synapomorphies: strongly bulging S1+2; very slender and dorsally situated internal process of gonostylus. Its closest relative obviously is Herniosina bequaerti having similarly (albeit much more) prolonged and basally fused medial processes of S5, a small medial apically pointed process of cercus and more robust funnel-shaped apex of distiphallus.

Biology.

The holotype of Herniosina erymantha sp. n. was sifted towards the end of May from dead leaves under Platanus trees (see Fig. 13, arrow) in a valley of a montane brook in the western ridge of the Erimanthos Mts (Fig. 12). The microhabitat (layers of decaying leaves of broad-leaved trees) is similar to that known for Herniosina horrida and Herniosina pollex in Central Europe (see under these species).

Distribution.

Hitherto only known from Greece: NW Peloponnese.