Eoplatypalpus sachalinensis Shamshev & Vasilenko & Perkovsky 2025, sp. nov.
Creators: name: Shamshev, Igor V.
name: Vasilenko, Dmitry V.
name: Perkovsky, Evgeny E.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Hybotidae
Eoplatypalpus
Eoplatypalpus sachalinensis

description: Eoplatypalpus sachalinensis Shamshev, sp. nov.
(Figs 1–3)
Type material. HOLOTYPE, ♂, Starodubskoye, Dolinsk district, Russia, Sakhalinian amber (PIN 3387/162A; syninclusions: 1 ♂ (PIN 3387/162B) and 1 ♀ (PIN 3387/162C) paratypes; 1 ♂ of Empidoidea (PIN 3387/162D), 1 specimen of Tachydromiinae (PIN 3387/162E), and a fragment of some Diptera (PIN 3387/162F). PARATYPES: 1 ♂, 1 ♀, Starodubskoye, Dolinsk district, Russia, Sakhalinian amber (PIN 3387/162c and PIN 3387/162d, respectively; in same amber piece with holotype); 1 ♀, Starodubskoye, Dolinsk district, Russia, Sakhalinian amber (PIN 3387/ 162g).
Remarks on type series. The holotype is in an amber nodule with syninclusions (Fig. 1). The specimen is nearly complete but in a poor condition. The body is somewhat squashed, cleared and deformed; some internal cavities are probably filled with a resin and the wings are somewhat shrunken.
The paratype male PIN 3387/162B rests near the holotype (Figs 1B, 2B), complete specimen, same condition as the holotype. The paratype female PIN 3387/162C is represented by an incomplete specimen: head and anterior part of thorax missing (Fig. 1C). The paratype female PIN 3387/ 162g is included in a separate, small, narrow, reddish yellow amber nodule together with a specimen of Aranea (3387/162h). The specimen is incomplete because a part of the nodule was probably broken off: head, most part of thorax anteriorly and fore legs missing. The left wing of PIN 3387/ 162g was photographed (Fig. 3B). The wing rests nearly in one plane, only a short portion of posterior margin is slightly deformed (concave).
Diagnosis. As for genus. Medium-sized, slender species.
Description. Male (Figs 2, 3A). Since the holotype and the paratype are affected by deformation due to preservation conditions, their body lengths are not to be considered natural. Based on well preserved wing of female, body length of the species is probably about 2.5 mm.
Head. Rather small, almost rounded in profile, distinctly convex both in front and occiput; ocellar triangle prominent, bearing 2 fine, moderately long setae; vertical setae undifferentiated; occiput with some fine, short setae. Antenna with postpedicel rather elongate (natural length unclear due to deformation; also scape unnaturally elongated), tapered, dorsal margin straight, ventral margin slightly convex; stylus terminal, probably slightly longer than postpedicel, faintly pubescent. Proboscis rather weak, straight, nearly half as long as head height; palpus small, narrow, with scattered, short fine setae.
Thorax. Pruinescence or tomentum undistinguishable. Postpronotal lobe prominent, small, with fine setae. Mesoscutum entirely covered with short, fine setae, rows of acrostichals and dorsocentrals undifferentiated; row of 4 short supra-alar setae present; scutellum with 3 pairs of long, fine setae of different lengths, apical pair somewhat longer.
Legs. Long, slender, without any special raptorial modifications; covered with fine, hair-like setae. Femora of subequal widths; fore femur with somewhat longer setae ventrally than mid and hind femora; mid femur only with rows of short, fine setae ventrally. Fore tibia probably slightly thickened; mid tibia without apical projections; hind tibia slightly thickened towards apex, covered with denser and slightly longer setae subapically. Fore and mid tarsi of subequal lengths, hind tarsus somewhat longer; all tarsomeres covered with rather dense and slightly longer setulae, bearing erect setulae ventrally; claws elongate.
Wing (Fig. 3B, C). Long, narrow, of nearly equal width at basal and apical third, nearly 4X as long as width opposite apex of vein R 1; membrane hyaline, covered with distinct microtrichia. Costal vein as in Symballophthalmus, strong up to apex of M 1, very weak along lower margin; with 3–4 fine setae near base. Sc evanescent, incomplete; R 1 meeting costa at approximately midpoint of wing; Rs originating at about proximal 1/6 between humeral crossvein and apex of vein R 1, long, nearly 4.5X longer than basal portion of R 4+5; R 2+3 straight, R 4+5 and M 1 divergent at base, nearly parallel in remaining part. Cells br and bm of approximately equal lengths (along upper margin of bm) and almost aligned apically, br narrow, bm nearly 2X as wide as br. Crossvein bm-m touching or nearly so with crossvein r-m, slightly oblique. Cell cua absent (vein CuA absent but some free portion of vein CuA+CuP present as scarcely visible trace). Anal lobe scarcely prominent.
Abdomen. Tergites covered with short to moderately long, fine setae. Hypopygium moderately large, more or less elongate oval, natural rotation degree unclear due to deformation, probably rotated 45–90° (holotype hypopygium deformed and partly broken); separate sclerites unrecognisable due to deformation.
Female. Wing length 2.8 mm. Similar to male.Abdomen long, telescopic, pointed; terminal segments somewhat deformed but generally resembles Symballophthalmus. Cercus (Fig. 3D, E) long, slender, covered with setulae.
Etymology. The epithet refers to the type locality, Sakhalin Island, Russia.
Distribution. Sakhalinian amber.
description: Published as part of Shamshev, Igor V., Vasilenko, Dmitry V. & Perkovsky, Evgeny E., 2025, A new genus of hybotid dance fly (Diptera: Hybotidae, Tachydromiinae) from the Eocene Sakhalinian amber, pp. 283-294 in Zootaxa 5575 (2) on pages 285-288, DOI: 10.11646/zootaxa.5575.2.4, http://zenodo.org/record/14746881