Itaphlebia elegana Cao, Shih & Ren sp. nov.

Figs 3, 4, 5

Etymology.

The specific name is from Latin adjective “elegans”, referring to the elegant body posture.

Type material.

Holotype: female, No. CNU-MEC-NN2008228 p/c (Fig. 3), preserved in lateral view, thorax partly preserved, abdomen well-preserved, with four wings partly preserved, veins of one forewing mostly discernible, veins of one hind wing relatively discernible. Paratypes: sex unknown, No. CNU-MEC-NN2015026 (Fig. 4), preserved in ventral view, thorax and abdomen partly preserved, only right forewing venation clearly discernible; female, CNU-MEC-NN2016020 p/c (Fig. 5), body nearly complete but not well-preserved, forewing venation partly discernible.

Locality and horizon.

All specimens were collected from the Jiulongshan Formation, latest Middle Jurassic age (Bathonian-Callovian boundary interval) from Daohugou Village, Ningcheng County, Inner Mongolia Autonomous Region in China.

Diagnosis.

On forewing, costal area slightly broad; Sc forking with three branches; Rs (R2 to R5) forking with five branches; R2+3 forking before the crossvein r3-r4; R4+5 forking before the crossvein r5-m1+2; crossvein cu1-cu2 near the forking of Cu1+M, and crossvein cu1-m4 far before M3+4 forking. Long and robust setae present on anal veins of forewing.

Description.

Mainly based on Holotype, unless indicated as paratype.

Thorax: Incompletely preserved, setae discernible.

Wing: Long and oval, basal part of the wing narrow, gradually broadening from the base toward the apex. Forewing with the basal part of C somewhat convex, anterior area slightly broad, pterostigma incompletely preserved; Sc with three branches, Sc1 and Sc2 ending at C before the middle of the wing length, Sc3 near pterostigmal area; Rs forking with five branches, one short crossvein sc-r before pterostigma, crossvein r1-r2 under the pterostigma, approximately near the forking of R2+3, crossvein r2+3-r4 before crossvein sc-r, oblique crossvein r3-r4 between R3 and R4, R2+3 four times as long as R4+5, R4 forking with two branches (R4a, R4b), oblique crossvein r5-m1+2 emerged after the forking of R4+5, crossvein r5-m1 present before the crossvein r4-r5; conspicuous thyridium at the forking of M; M with four branches, M3+4 divided beyond the forking of M1+2; straight crossvein m1+2-m3 forking at the middle length of M1+2; crossvein m-cu1 before the forking of M3+4; Cu1 coalesced with M for a relatively short distance and separated from M near the crossvein cu1-cu2; long and robust setae present on veins A1 and A2, A1 and A2 almost parallel; crossvein a1-a2 at the same level of Cu1; A3 absent. Hind wing shorter and broader than forewing; pterostigma preserved in hind wing. Sc simple, terminated at C in the first one third of wing; R1 under pterostigma and connecting with C by a short crossvein c-r1, Rs with four branches, two crossveins between R2+3 and R4. Anal margins in hind wings not preserved, several long and robust setae preserved.

Abdomen: With 11 visible abdominal segments, segments VIII-XI distinctly smaller than segment VII, a pair of cerci at the end of abdomen, each one with three segments, setae discernible.

Remarks.

Itaphlebia elegana sp. nov. demonstrates an individual aberration of the sixth branch of R vein by the forking of R4, providing a character for understanding the evolution of wing venation. Although the hind wing has R with five branches, the diagnosis of Itaphlebia should be revised to indicate that the forewing Rs forking with four or five branches. CNU-MEC-NN2008228 p/c has two crossveins between R1+2 and R3+4, but only one crossvein is visible in CNU-MEC-NN2016020 p/c and CNU-MEC-NN2016026 p/c. Considering these three specimens have many similarities regarding other characters, we regard them as the same species. The difference in crossveins between R2+3 and R4 might have been due to the intraspecific difference or inheritable mutations.

Measurements

(in mm). Holotype: female, No. CNU-MEC-NN2008228 p/c: Abdomen length 6.0, forewing length 9.4, hind wing length 7.5 (all as preserved). Paratypes: sex unknown, No. CNU-MEC-NN2015026: thorax length 1.8, thorax maximum width 1.1, forewing length 7.5, forewing maximum width 3.0 (all as preserved); female, CNU-MEC-NN2016020 p/c: head length 1.1 (excluding the antenna), head maximum width 0.8 (excluding the antenna), thorax length 2.2, thorax maximum width 1.7, forewing length 8.4, forewing maximum width 3.5 (all as preserved).