Rhynchoraphidia, 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 : 308-312

Genus Rhynchoraphidia gen. nov.

( Figs. 5–6 )

Type species: Rhynchoraphidia burmana sp. nov.

Diagnosis. Minute size. Head ovoid, with portion posterior to compound eyes shorter than eye length and tapering caudad; clypeus slightly prolonged and distinctly narrowed, nearly as long as compound eye length; compound eyes large and ovoid; ocelli absent; antennae possibly long. Pronotum slightly shorter than head, with a constant height along entire length. All tibiae swollen, lacking specialized spines; tibial spurs absent. Wings narrowly elongate. Forewing: Costal space distinctly broadened at its midpoint; pterostigma elongate, ~1/4× wing length, medially with a pterostigmal crossvein, proximally closed by a crossvein and distally closed by a veinlet of RA; Scp terminating into C slightly proximad wing midpoint; posterior veinlet of RA continuous with stem of RA; RP with anterior branch proximally not angled; two radial cells, one discal cell, and one discoidal cell present. Hindwing: Stem of MA proximally fused with MP; CuA distally bifurcated; an oblique proximal mp-cua present; three radial cells, one discal cell, and one discoidal cell present.

Etymology. From “ rhyncho -”, rostrate, and Raphidia , a common genus-group name of Raphidioptera , in reference to the prolonged and narrowed clypeus, of the new genus. Gender: feminine.

Remarks. The new genus appears to be closely related to Alavaraphidia Pérez-de la Fuente, Peñalver, Delclòs & Engel, 2012 in having similar prolonged clypeus and swollen tibiae, but can be separated from the latter genus by the absence of ocelli (three ocelli present in Alavaraphidia) and the tarsomere 3 without digitiform processes (six to eighth digitiform processes present on bilobed extentions in Alavaraphidia). Among the nanoraphidiine genera, Rynchoraphidia gen. nov. also shares the presence of pterostigmal crossvein with the contemporary genus Burmoraphidia gen. nov. while it can be distinguished from the latter genus based on the absence of ocelli (three ocelli present in Burmoraphidia gen. nov.), the pterostigma proximally closed by a crossvein (pterostigma proximally diffused in Burmoraphidia gen. nov.), and the swollen metatibia (metatibia not swollen in Burmoraphidia gen. nov.).

Rhynchoraphidia burmana sp. nov. ( Figs. 5–6 )

Diagnosis. As for the genus.

Description. Holotype EMTG BA-002256. Female. Body length 5.1 mm (measured without ovipositor) and 7.4 mm (measured with ovipositor). Body generally blackish brown except for pale legs.

Head ovoid, 0.9 mm long, with portion posterior to compound eyes shorter than eye length and tapering caudad; clypeus distinctly narrowed and slightly prolonged, nearly as long as compound eye length. Compound eyes large and ovoid, separated by distance slightly shorter than compound eye length. Ocelli absent. Antennae inserted at position slightly posteriad anterior tangent of compound eyes, with only proximal parts preserved; preserved part of antenna about 1.0 mm; scape subcylindrical, strongly robust; pedicel subcylindrical, about half length of scape, and slightly thicker than neighboring flagellomere; flagellum damaged, entire length unknown, but possibly long. Mouthparts not clearly visible, with short maxillary palps.

Prothorax 0.6 mm long, meso- plus metathorax 0.9 mm long; pronotum slightly shorter than head, with a constant height along its entire length, and with anterolateral portions slightly expanded. Legs short, densely setose; all tibiae swollen and lacking spines; tarsomere 3 bilobed; pretarsal claws simple, with a basal enlargement; arolium reduced.

Wings hyaline, veins dark, with short setae. Forewing length 4.4 mm, maximum width 0.8 mm; costal space distinctly broadened at its midpoint (at widest point costal space ~1.4× width of pterostigma); three costal crossveins present; ScP terminating into C slightly proximad wing midpoint; pterostigma elongate (1.1 mm long), ~1/4× forewing length, with constant width along its entire length, and medially with an oblique pterostigmal crossvein; pterostigma starting 0.3 mm (~4.0× 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 simple or with two short branches, anterior branch not zig-zagged with stem of RP; MA with two branches; 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 3.6 mm, maximum width 0.7 mm; costal space distinctly narrower than that of forewing; two costal crossveins present; pterostigma elongate (1.0 mm long), with constant width along its entire length, and with indistinct trace of a pterostigmal crossvein at distal 1/3; pterostigma starting 0.3 mm (slightly more than 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 short branches; MA with two branches, stem of MA proximally fused with MP; three radials cells and one distal cell present; MP with two long, distally bifurcated branches; one discoidal cell present; an oblique proximal mp-cua present; CuA distally bifurcated.

Abdomen length 2.6 mm (measured without ovipositor) and 4.4 mm (measured with ovipositor). Genitalia: Genital sclerites not clearly visible; ectoproct small; ovipositor 2.5 mm long and 0.1 mm thick, distally tapering, with digitiform gonostyli.

Type material. Holotype EMTG BA-002256: amber piece preserving a complete adult female of R. burmana , a thripid, and a midge; it is polished in the form of a subtriangular cabochon, slightly obscure, with length×width about 24.1× 16.2 mm, height about 10.7 mm.

Etymology. The specific epithet “ burmana ” refers to the occurrence of the new species in the Early Cretaceous Burmese amber.

Remarks. By having the narrow wings and pterostigmal crossvein, the new species somewhat resembles D. engeli sp. nov., but it can be distinguished from the latter species by the narrowly prolonged clypeus and the shape of RP fork.

Genus Burmoraphidia gen. nov. ( Figs. 7–11 )

Type species: Burmoraphidia reni sp. nov.

Diagnosis. Minute size. Head ovoid, with portion posterior to compound eyes shorter than eye length and tapering caudad, and with clypeus slightly shorter than compound eye length; compound eyes large, ovoid; three small ocelli present on posterior half of head; antenna much longer than head plus prothorax, but shorter than entire body length, with ~40 flagellomeres. Pronotum slightly shorter than head, with a constant height along entire length. Pro- and mesotibiae swollen, but metatibia slender, tibial spurs present. Forewing: Costal space distinctly broadened (at widest point costal space ~1.5× width of pterostigma); pterostigma elongate, ~1/3× wing length, proximally diffused but not closed by a crossvein, starting proximad termination of Scp, with an oblique pterostigmal crossvein slightly distad midpoint of pterostigma, distally closed by a veinlet of RA; ScP terminating into C slightly distad wing midpoint; posterior veinlet of RA prolonged and zig-zagged with stem of RA; RP simple; two radial cells, one discal cell, and two discoidal cells present. Hindwing: Configuration of pterostigmal area same to that of male; stem of MA proximally fused with RA; an oblique proximal mp-cua present; two radial cells, one discal cell, and one discoidal cell present; A1 distally bifurcated and medially fused with A2 for a short distance, proximally forming an ovoid anal cell.

Etymology. From Burma and Raphidia , a common genus-group name of Raphidioptera , in reference to the occurrence of the new genus from the mid Cretaceous Burmese amber. Gender: feminine.

Remarks. The new genus differs from all other nanoraphidiine genera by the pterostigma with a pterostigmal crossvein and a diffuse base.

Figures

FIGURE 5. Rhynchoraphidia burmana gen. et sp. nov., holotype EMTG BA- 002256. A. Habitus in dorsal view; B. Head and thorax in dorsal view; C. distal parts of left wings; D. Drawing of head and prothorax in dorsal view. Arrow indicating pterostigmal crossvein. Scale bar = 1.0 mm.

FIGURE 6. Rhynchoraphidia burmana gen. et sp. nov. A. Holotype EMTG BA- 002256, drawing of right fore- and hindwing; B. same specimen, drawing of left fore- and hindwing. Scale bar = 1.0 mm.

FIGURE 7. Burmoraphidia reni gen. et sp. nov., female. A. Holotype EMTG BA- 001272, habitus in dorsal view; B. Paratype EMTG BA- 002135, habitus in dorsal view; C. Paratype EMTG BA- 002260, habitus in dorsal view; D. Paratype EMTG BA- 0 0 2254, habitus in dorsal view. Arrows indicating pterostigmal crossvein. Scale bar = 1.0 mm.

FIGURE 8. Burmoraphidia reni gen. et sp. nov., male. A. Paratype EMTG BA- 001772, habitus in dorsal view; B. Paratype EMTG BA- 002158, habitus in ventral view; C. Paratype EMTG BA- 002255, habitus in ventral view; D. Paratype EMTG BA- 0 0 2197, habitus in laterocaudal view. Scale bar = 1.0 mm.

FIGURE 9. Burmoraphidia reni gen. et sp. nov., holotype EMTG BA- 001272, drawing of fore- and hindwing. Scale bar = 1.0 mm.

FIGURE 10. Male genitalia of Burmoraphidia reni gen. et sp. nov. A. Paratype EMTG BA- 001772, photo in lateral view; B. Paratype EMTG BA- 001772, drawing in lateral view; C. Paratype EMTG BA- 002158, photo in ventral view; D. Paratype EMTG BA- 002158, drawing in ventral view; E. Paratype EMTG BA- 002197, photo in caudal view; F. Paratype EMTG BA- 0 0 2197, drawing in caudal view. Arrows indicating distal forking of the central structure. T: tergum; S: sternum; gx: gonocoxite; gp: gonapophysis; e: ectoproct. Scale bar = 0.5 mm.

FIGURE 11. Female genitalia of Burmoraphidia reni gen. et sp. nov. A. Paratype EMTG BA- 002260, photo in ventral view; B. Paratype EMTG BA- 002260, drawing in ventral view; C. Paratype EMTG BA- 002135, photo in lateral view; D. Paratype EMTG BA- 002135, drawing in lateral view; E. Paratype EMTG BA- 002254, drawing in lateral view. T: tergum; S: sternum; sg: subgenitale; gst: gonostylus; op: ovipositor; e: ectoproct. Scale bar = 0.5 mm.