Allopteroneura burmana Lu, Zhang & Liu, 2019

Allopteroneura burmana Lu, Zhang & Liu sp. nov.

( Figs 1 View Figure 1 , 2 View Figure 2 )

Diagnosis. As for the genus.

Material. Holotype, EMTG BU-002082 , amber piece preserving a partly preserved adult of Allopteroneura burmana , together with several springtails, beetles, hymenopterans, dipterans, mites and spiders. It is polished in the form of a flattened rectangle cabochon, with length × width about 45.0 × 38.0 mm, height about 8.0 mm .

Etymology. The specific epithet ‘ burmana ’ refers to the occurrence of the new species in mid-Cretaceous Burmese amber. An adjective in the feminine gender.

Description. Body length 16.15 mm; head 0.61 mm long and 2.25 mm wide; distance between compound eyes 0.97 mm; diameter of compound eye 0.37 mm; antenna length 4.86 mm; prothorax 1.49 mm long and 0.87 mm wide; mesothorax 1.52 mm long and 2.14 mm wide; metathorax 0.99 mm long and 2.24 mm wide; preserved part of left forewing 27.99 mm long and 6.54 mm wide; preserved part of right hind wing 13.67 mm long and 6.22 mm wide; preserved part of abdomen 11.70 mm long.

Head orthognathous. Compound eyes large, semi-globular; diameter of eyes much shorter than distance between compound eyes. Antenna clubbed, nearly as long as length of head plus thorax; flagellomere about twice as long as wide.

Prothorax slightly widened posteriad, much longer but narrower than head; meso- and metathorax robust, metathorax almost as wide as mesothorax. Wings elongated, transparent and immaculate.

Forewing leaf-like, elongated, with narrow wing base and acuminated apex. Costal space quite narrow proximally, but strongly widened medially, and again slightly narrowed distad, with 37 preserved simple veinlets; costal space much wider than subcostal space, but narrower than RA space. ScA absent; ScP and RA fused together before reaching to wing apex; subcostal crossveins absent. Presectorial crossveins absent. Hypostigmal cell incompletely preserved, but apparently long. RP þ MA originating slightly distad wing base; RP and MA diverging almost from wing midpoint; RP pectinately branched from its mid-length, with a few crossveins allied as a longitudinal line; 22 crossveins present in RA space; infra radial cell thin and long. M proximally leaving a short oblique stem of MA that is fused with R near wing base; MA distally with five branches. MP1 long, almost straight for a long distance, distally slightly curved, with three branches. Base of MP2 (oblique vein) present proximad of initial branching point of MP 2 þ CuA. CuA and CuP diverging near wing base; MP 2 þ CuA pectinately branched from proximal 1/4, with 11 strongly zig-zagged branches, among which a series of curving crossveins are present and form eight subtrapezoidal cells with stem and branches of CuA; distal fork of branch of MP 2 þ CuA nearly rectangular; CuP pectinately branched into five simple branches; six cua-cup crossveins present. A1 proximally parallel to but not fused into CuP, distally with two simple branches; A 2 þ A3 short, proximally quite approximating and parallel to A1, with three branches.

Hind wing partly preserved. Costal space broad, much broader than that of forewing. Presectorial crossveins absent. Seven crossveins present in RA space. MP diverging into MP1 and MP2 at wing base. CuP pectinately branched.

Legs slender and long; femora, tibiae and tarsi bearing several long spinous setae, which are much longer on tibiae (almost half-length of tibia) than those on femora and tarsi, tibial spurs slightly longer and stronger than tibial spinous setae, and slightly longer than tarsomere 1; numerous short spinous setae also present along tibiae and tarsi; tarsus slightly longer than tibia, 5-segmented, tarsomere 1 longest, tarsomeres 2 and 3 almost equal in length, tarsomere 4 shortest and only half-length of tarsomere 3, tarsomere 5 slightly shorter than tarsomere 1; paired simple pretarsal claws present, prolonged and distally curved, opposable on last tarsomere; arolium absent.

Abdomen slenderly elongate, almost 3/4 × body length; anterior three segments much thinner than remaining segments. Genitalia not preserved.

Remarks. Considering the aforementioned morphological similarity between Allopteroneura gen. nov. and the three species of Cratoneura , the new species differs from C. dividens , C. minor and C. pulchella by the configuration of the forewing MP 2 þ CuA branching area, particularly the presence of eight subtrapezoidal cells along its stem.