Dolichoraphidia engeli, Liu, Xingyue, Lu, Xiumei & Zhang, Weiwei, 2016

Liu, Xingyue, Lu, Xiumei & Zhang, Weiwei, 2016, New genera and species of the minute snakeflies (Raphidioptera: Mesoraphidiidae: Nanoraphidiini) from the mid Cretaceous of Myanmar, Zootaxa 4103 (4), pp. 301-324 : 306-308

Dolichoraphidia engeli sp. nov.

( Figs. 3–4 )

Diagnosis. Mostly as for the genus. Specific diagnosis: Antenna extremely long, ~2.5 times as long as body length, with over 100 flagellomeres; only one forewing discoidal cell present; both fore- and hind wing with a weak pterostigmal crossvein.

Description. Holotype BA001300 . Female. Body length 4.2 mm (measured without ovipositor) and 6.0 mm (measured with ovipositor). Body generally dark brown, but venters of meso- and metathorax much paler; legs pale.

Head ovoid, ~ 0.3 mm long, with portion posterior to compound eyes shorter than eye length and tapering caudad. Compound eyes large and ovoid, separated by distance slightly greater than compound eye length. Ocelli absent. Antennae inserted at anterior tangent of compound eyes; antenna length 13.0 mm; scape subcylindrical, strongly robust; pedicel subcylindrical, about half length of scape, slightly thicker than neighboring flagellomere; flagellum extremely long, with over 100 flagellomeres, bearing sparse, minute setae. Mouthparts not clearly visible.

Prothorax 0.4 mm long, meso- plus metathorax 0.8 mm long; pronotum slightly longer than head, with a constant height along its entire length. Legs slenderly elongate, densely setose; all tibiae swollen and distally bearing a row of spines; tarsomere 3 bilobed; pretarsal claws simple, slightly enlarged basad; arolium reduced.

Wings hyaline, veins dark, with short setae. Forewing length 4.7 mm, maximum width 1.2 mm; costal space narrow (at widest point costal space as wide as pterostigma); four costal crossveins present; ScP terminating into C at wing midpoint; pterostigma elongate (1.0 mm long), ~1/5× forewing length, with constant width along its entire length, and with a weak pterostigmal crossvein; pterostigma starting 0.5 mm (~5.0× pterostigmal width) beyond termination of ScP, proximally closed by a crossvein and distally closed by anterior veinlet of RA; only 1scp-ra present; RA distally bifurcated, with posterior branch continuous with its stem; RP with two branches; MA with two branches; stem of RP extremely short in comparison with stem of MA; two radial cells and one discal cell present; MP with two long, distally bifurcated branches; one discoidal cell present; CuA distally bifurcated, with anterior branch partially fused with posterior branch of MP. Hindwing length 3.8 mm, maximum width 1.1 mm; costal space slightly narrower than that of forewing; three costal crossveins present; pterostigma elongate (1.1 mm long), with constant width along its entire length, and with a weak pterostigmal crossvein; pterostigma starting 0.3 mm (~3.0× pterostigmal width) beyond termination of ScP, proximally closed by a crossvein and distally closed by anterior veinlet of RA; RA distally bifurcated, with posterior branch continuous with its stem; RP with two branches; MA with two branches, stem of MA proximally fused with MP; three radial cells present, but no discal cell; MP with two long, distally bifurcated branches; one discoidal cell present; an oblique proximal mp-cua present; CuA simple.

Abdomen length 2.5 mm (measured without ovipositor) and 4.4 mm (measured with ovipositor). Genitalia: Genital sclerites not clearly visible; ovipositor 1.9 mm long and 0.05 mm thick, distally tapering, with digitiform gonostyli.

Paratype BA001252 . Female. Body length 4.2 mm (measured without ovipositor) and 6.8 mm (measured with ovipositor). Head length 0.4 mm; distal parts of antennae not preserved; prothorax length 0.4 mm; meso- plus metathorax length 0.7 mm; forewing length 4.2 mm, maximum width 1.1 mm; hindwing length 3.7 mm, maximum width 0.8 mm; abdomen length 2.5 mm (measured without ovipositor) and 5.1 mm (measured with ovipositor); ovipositor 2.6 mm long and 0.05 mm wide. General morphology and wing venation almost same to that in holotype female. But, hindwing with one discal cell and with CuA distally bifurcated. Genitalia with sclerites other than ovipositor poorly preserved; configuration of genitalia same to that of holotype female.

Type materials. Holotype EMTG BA-001300: amber piece preserving a complete adult female of D. engeli (body slightly shrinking and decaying), several thrips and beetles, and a spider; it is polished in the form of a semiellipsoid cabochon, clear and transparent, with length×width about 32.3× 11.7 mm, height about 7.8 mm. Paratype EMTG BA-001252: amber piece preserving a complete adult female of D. engeli (distal parts of antennae and most parts of left wings not preserved), four thrips, and a psocopteran; it is polished in the form of a semi-ellipsoid cabochon, clear and transparent, with length×width about 19.0× 14.1 mm, height about 3.7 mm.

Etymology. The new species is dedicated to Dr. Michael S. Engel for his contributions on the taxonomy of fossil Raphidioptera .

Remarks. The new species differs from D. aspoecki sp. nov. by the presence of only one forewing discoidal cell and a weak pterostigmal crossvein in both fore- and hind wing. Between the two females of this new species, we found several distinct variations of wing venation, such as the presence/absence of hindwing discal cell (dc absent in holotype but present in paratype) and the branching condition of hindwing CuA (CuA simple in holotype but distally bifurcated in paratype). It is important to further understand the range of individual venational variations of snakeflies for accurate identification.

Figures

FIGURE 3. Dolichoraphidia engeli gen. et sp. nov. A. Holotype EMTG BA- 001300, habtius in dorsal view; B. Same specimen, fore- and hindwing; C. Same specimen, ovipositor in ventral view; D. Same specimen, drawing of ovipositor in ventral view; E. Paratype EMTG BA- 001252, habitus in dorsal view. Arrows indicating pterostigmal crossvein. Scale bar = 1.0 mm.

FIGURE 4. Dolichoraphidia engeli gen. et sp. nov., holotype EMTG BA 001300, drawing of fore- and hindwing. Scale bar = 1.0 mm.