Archaeohelorus hoi Shih, Feng & Ren, 2011

Forewing 2cu-a intersecting Cu and Rs+M at the same point or postfurcal. Hind wing may have tubular veins C and Sc+R separated at base, R developed, M+Cu robust and forking at the basal part, M and Cu distinct, or simplified venation.

Archaeohelorus hoi Shih, Feng & Ren, 2011, Archaeohelorus polyneurus sp. n. and Archaeohelorus tensus sp. n.

This genus was established by Shih et al. 2011 based on a holotype, allotype and six paratypes from the Middle Jurassic of Daohugou, Inner Mongolia, China. Due to lack of discernible hind wings on the fossils of holotype and allotype, the hind wing venation was not described. With the new forewing and hind wing venational information on our new materials, we emended the generic diagnosis.

The specific nameis from Greek word “polyneurus”, means “many veins”, referring to the complete venation of the hind wing preserved.

Holotype, CNU-HYM-NN2012052, dorsal view, gender unknown. A well-preserved body with almost complete forewings and hind wings and part of legs, but head missing. Paratype: CNU-HY-NN2008010, dorsal view, a well-preserved almost complete body with forewings and right hind wing and part of legs, previously mis-identified as a paratype of Archaeohelorus hoi.

Jiulongshan Formation, Middle Jurassic, Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China.

In forewing, 2cu-a intersecting Cu and Rs+M at the same point and cell r obtuse-angled triangular (vs. approximately right-angled triangular in Archaeohelorus hoi). Hind wing with Sc+R confluent with C and extended to costal margin, R developed. M+Cu distinct and forking at the basal part, M and Cu robust.

Upon further examination, we found that a paratype of Archaeohelorus hoi, CNU-HYM-NN2008010, has forewing 2cu-a intersecting Cu and Rs+M at the same point and cell r obtuse-angled triangular (vs. approximately right-angled triangular in Archaeohelorus hoi); and hind wing with tubular vein C parallel with Sc+R at base, M+Cu robust and forking at the basal section, M long, 1-Cu, 2-Cu distinct. These venational characters are consistent with the diagnostic characters of Archaeohelorus polyneurus sp. n., hence we transfer CNU-HYM-NN2008010 as a paratype of Archaeohelorus polyneurus sp. n.

A medium-sized body with both forewings and hind wings well-preserved, but, without head (Fig. 1). Forewing broad. Mesosoma suboval, nearly 1.35 times as long as wide; mesoscutum trapezoidal with notauli distinct and concave; tegula triangular; scutellum broad with two rows of pits; metanotum relatively wide with plenty of pits; propodeum transverse, 2.89 times as broad as long.

Metasoma suboval with six segments; first metasomal segment transverse, second segment with several longitudinal ridges; third and fourth segments trapezoidal with shorter longitudinal ridges anteriorly; other ones smooth; the end of terminal segment not preserved.

Forewing broad and subtriangular. Pterostigma long and acute apically, not widened beyond mid-length. C robust and extending to apex of forewing. 2r-rs arising from basal one third of pterostigma, slightly oblique apicad, slightly longer than pterostigmal width. R robust, cell r obtuse-angled triangular and closed by R, M+Cu, 1-Rs and 1-M; Rs straight and intersecting with distal part of C. Cell 1+2r six-sided and surrounded by R, 1-Rs, 1-Rs+M, 2-Rs+M, 2-Rs, and 2r-rs. M+Cu straight and distinct; M and Cu distinct, M straight, Cu break after 1m-cu. 1-Rs as long as 1-M and slightly inclined toward wing base. Cell 1mcu small and subtriangular. M and Rs branching at 30% from 1m-cu of the length between 1m-cu and 2r-rs. 1cu-a and 2cu-a distinct and reaching A. 1cu-a in line with 1-M; and 2cu-a intersecting Cu and Rs+M at the same point.

Hind wing with tubular veins C parallel with Sc+R at base; R developed and Rs preserved; M+Cu robust and forking at the basal section, M and 1-Cu long and distinct, 2-Cu long.

Right foreleg with only coxa and femur partially preserved. Right midleg with partial trochanter, spindle-shaped femur and partial tibia preserved. Right hindleg with partial coxa, trochanter trapezoidal and small, robust spindle-shaped femur, long tibia swollen distally with spurs, tarsi with five segments, basitarsus longest and two claws fixing the end of pretarsus.

Measurements (in mm). Mesosoma length 3.36, width 2.48; metasoma > 3.38 long; lengths of the first to fifth metasomal segments are 0.34, 0.51, 0.72, 0.94, and 0.55; forewing length 6.52, width > 3.05.

Body medium-sized (Fig. 2). Head oval and antennae filiform and thick, scape swollen and bell-shaped, only first and second flagellomeres preserved. Mesosoma, forewing and metasoma same as holotype, the end of terminal segment not preserved. Hind wing with tubular vein C parallel with Sc+R at base, M+Cu robust and forking at the basal section, M long, 1-Cu, 2-Cu distinct. Left foreleg and right midleg with only coxa and femur partially preserved. Left midleg with femur robust and tibia long, left hindleg with femur robust and spindle-shaped, long tibia swollen distally. Right hindleg with femur robust and spindle-shaped, tibia partially preserved.

Measurements (in mm). Body length > 14.6; head length 1.89, width 1.53; mesosoma length 3.58, width 2.52; metasoma length 3.68; forewing length > 6.54, width > 2.88.

This species can be assigned to Archaeohelorus Shih, Feng & Ren, 2011 by its metasoma with six segments and the first segment narrow and transverse. Forewing 1-Rs as long as 1-M. Cell 1mcu small and subtriangular, 1cu-a in line with 1-M; and 2cu-a intersecting Cu and Rs+M at the same point. Compared with Archaeohelorus hoi, Archaeohelorus polyneurus has preserved hind wing with Sc+R confluent with C and extended to costal margin, R developed. M+Cu distinct and forking at the basal part, M and Cu robust; in forewing, cell r obtuse-angled triangular (vs. approximately right-angled triangular in Archaeohelorus hoi). Besides, Archaeohelorus polyneurus has a much larger body size than Archaeohelorus hoi, length of forewing 6.52 mm or > 6.54 mm (vs. 3.17 mm in Archaeohelorus hoi).

The specific name “tensus” means stretching and long, referring to the shape of the forewing.

Holotype, CNU-HYM-NN2012056p/c, part and counterpart, dorsal view, male. A well-preserved almost complete body with antenna, forewings and part of legs and partial hind wings.

Jiulongshan Formation, Middle Jurassic, Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China.

Forewing 2cu-a postfurcal with intersection of Cu and Rs+M. First abscissa of Rs (1-Rs) and basal section of M (1-M) arched toward basal of wing. Hind wing with tubular veins C, Sc+R, and Rs preserved.

A smalladult specimen with a total body length of 4.4 mm. Head suboval and large relative to mesosoma in width. Eyes large, and located at the both sides of the head.

Antennae filiform, thick, with 6 segments preserved on left and 5 segments preserved on right. Scape swollen and bell-shaped; pedicel short and quadrate; subsequent flagellomeres not well preserved.

Mesosoma subhexagonal and broader than head; pronotum narrower than head, short, probably covered by mesonotum; mesoscutum distorted in the middle and trapezoidal with notauli not distinct but preserved; tegula large and subtriangular; scutellum round with pits anteriorly; propodeum narrow, transverse and areolated.

Metasoma suboval with seven segments; first metasomal segment transverse with several longitudinal ridges; second segment trapezoidal with less longitudinal ridges anteriorly; other ones smooth; the male terminalia triangular, partially covered by the previous segment.

Forewing broad and subtriangular. Pterostigma long and acute apically, not widened beyond mid-length. C robust and extending near the apex of forewing. 2r-rs arising from basal one third of pterostigma, slightly longer than the width of pterostigma, and slightly oblique apicad. R robust and cell r closed with C, R and 1-RS. Rs straight and intersecting with distal part of C. Cell 1+2r longer and narrower relatively and six-sided surrounded by R, 1-Rs, 1-Rs+M, 2-Rs+M, 2-Rs, and 2r-rs. M+Cu straight and distinct; M and Cu distinct, almost straight. 1-Rs as long as 1-M and slightly inclined toward wing base. Cell 1mcu small, subtriangular and relatively slender with 2-M+Cu 4.3 times as long as 1-M. M and Rs branching at 30% from 1m-cu of the length between 1m-cu and 2r-rs. 1cu-a and 2cu-a distinct and reaching A. 1cu-a in line with 1-M; and 2cu-a postfurcal with Rs+M distinctly.

Hind wing, with tubular veins C parallel with Sc+R at base, Rs short, intersecting distal part of C.

Left foreleg, midleg and hindleg and right foreleg with only coxa and femur partially preserved, hind femur much thicker, nearly three times as long as wide; right midleg with partial spindle-shaped femur and partial tibia preserved, right hindleg with partial coxa, trapezoidal trochanter, robust spindle-shaped femur and relatively thin tibia and some parts of tarsus preserved.

Measurements (in mm): Body length 4.67, head length1.39, width 0.68, mesosoma length 1.68, width 1.36; metasoma 2.23 long; lengths of metasomal segments are 0.20, 0.39, 0.48, 0.38, 0.25 and 0.32; forewing length > 2.96, width > 1.36.

This species is assigned to Archaeohelorus Shih, Feng & Ren, 2011 by its seven separated metasomal segments, the first metasomal segment transverse with several longitudinal ridges. Forewing 1-Rs as long as 1-M. Cell 1mcu small and subtriangular, 1cu-a in line with 1-M. Compared with Archaeohelorus hoi, Archaeohelorus tensus has preserved hind wing with tubular veins C, Sc+R, R, and Rs preserved; in forewing, 2cu-a distinctly postfurcal with intersection of Cu and Rs+M (vs. 2cu-a intersecting Cu and Rs+M at the same point in Archaeohelorus hoi); cell 1mcu distinctly slender, 4.3 times as long as wide (vs. 2.4 times in Archaeohelorus hoi); 1-Rs and 1-M arched toward basal of wing (vs. 1-Rs and 1-M straight in Archaeohelorus hoi). It also differs from Archaeohelorus polyneurus by its postfurcal 2cu-a, slender cell 1mcu.