Neoarisemus groehni, WAGNER, 2021

WAGNER, RÜDIGER, 2021, Neoarisemus groehni sp. nov., a notable moth fly (Diptera, Psychodidae, Psychodinae) from Ukrainian amber, Palaeoentomology 4 (1), pp. 19-22 : 19-21

Neoarisemus groehni sp. nov.

( Fig. 1A )

Type material. The amber pieces with holotypus and paratypus ( GPIH no. 5029, coll. Gröhn no. 9200) are housed in the collection of the Geologisch-Palaeontologisches Institut of University Hamburg ( GPIH), the institution is now named CeNak ( Centrum of Natural History = Zentrum für Naturkunde). In the Museum of GPIH the collection of Mr. Carsten Gröhn is separately deposited. The holotype is placed deep in the amber of the large piece, the paratype lies close to the surface of the smaller amber piece.

Etymology. The new species is named after Carsten Gröhn who made the specimens available to the author.

Diagnosis. Neoarisemus groehni sp. nov. is characterized by the eye-bridge without suture, wing forks R 2/3 and R 2+3/4 near wing base, eversible whitish structures on head, terminalia with basally swollen epandrial appendages, and aedeagus with asymmetrical, blade shaped sclerites.

Description. Head with eye-bridge consisting of four facet rows, no interocular suture. On both sides of head occur large whitish probably eversible structures with dark center, larger than cornicula of known extant species. Antennae wrapped around body and randomly twisted around each another so that number and structure are not identifiable with certainty. Scape and pedicel not clearly visible; flagellum with probably 14 flagellomeres, most being bottle-shaped, with necks as long as inflated basal parts. Penultimate flagellomere bottle-shaped but shorter than previous segments, apical segment spherical ( Fig. 1B ). Ascoids not distinguishable from setae.

Thorax difficult to see in detail, without distinguishing features. Legs as well without distinctive features, partly covered with blackish setae.

Wing ( Fig. 1C ) as usual for genus, with Sc short; R 1 elongate, ending in costa at about level of M 4. Radius sector with four veins, forks R 2/3 and R 2+3/4 nearby in basal third of wing. R 5 ending in wing tip. Media forking at about middle of wing. Wing length 1.5 mm; body length 1.2 mm.

Abdomen with eight segments and terminalia ( Fig. 1D, E ). Hypandrium a thin band connected ring-shaped to rectangular epandrium. Epandrial processes about as long as epandrium, basally swollen, curved with apical retinacula (probably 2–4). Gonocoxites slightly bent, tubular, gonostyli longer than gonocoxites with a sharp tip that is bent up. A broad sclerite between gonocoxites, with sinuous apical edge. Behind it lies the roughly triangular elongate asymmetrical aedeagus with tip bent upward. At higher magnification, apical part apparently blade-like with asymmetric edges (Fig. E).

Remarks. The placement of the new species in Neoarisemus is certain: the head, antennae, wings, and terminalia fit the genus diagnosis ( Vaillant, 1975). The large pale structures on the head is a remarkable apomorphy of N. groehni sp. nov. However, it is not clear whether the large cross sclerite in the terminalia is part of the aedeagus, or broken from the apical aedeagus or even is a peculiar sclerite of its own. This uncertainty could not be solved comparing the two specimens.

Figures

FIGURE 1. Neoarisemus groehni sp. nov. A, Male, body from rear dorsal view (scale = 1 mm). B, Outlines of terminal flagellomeres. C, Wing (longitudinal veins and characteristic forks labelled). D, terminalia, oblique view (abbreviations: aed, aedeagus; epa, epandrium; epaa, epandrium appendages; gcx, gonocoxite; gst, gonostylus; hyp, hypandrium). E, Outlines of the asymmetrical aedeagus tip.