Exilibittacus foliaceus, Liu, Sulin, Shih, Chungkun & Ren, Dong, 2014

Liu, Sulin, Shih, Chungkun & Ren, Dong, 2014, Four new species of hangingflies (Insecta, Mecoptera, Bittacidae) from the Middle Jurassic of northeastern China, ZooKeys 466, pp. 77-94 : 84

Taxon classification Animalia Mecoptera Bittacidae

Exilibittacus foliaceus sp. n. Fig. 7

Etymology.

The Latin word of “foliaceus” means folliform, referring to the shape of the wings like leaves.

Holotype.

Female, CNU-MEC-NN2013010, in dorsal view. Body length 12.9 mm, forewing 11.7 mm long and 2.9 mm wide; hind wing 9.7 mm long and 2.6 mm wide.

Horizon and locality.

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

Diagnosis.

Forewing: pterostigmal crossveins (Pcv) absent, but 2A present. Hind wing: Rs with four branches and the bifurcation of Rs at the same level of the bifurcation of M.

Description.

A female holotype preserved in dorsal view. Antenna filiform, scape, pedicel and part of other antennomeres preserved. The vertex of the head raised. Legs not well-preserved, covered with short setae; the fifth tarsomere folded against the fourth, a claw present (Fig. 7A, B).

Forewing. The base of wings narrow, pterostigma slightly dark. Sc terminating at the anterior margin proximad of the R4+5 forking; one subcostal crossvein (Scv) between Sc and R1; R1 running straight through pterostigma, without sagging; one crossvein between R1 and R2+3; Rs with four branches, R4 slightly curved at beginning and then parallel with R5; one crossvein between R2+3 and R4 and one crossvein between R4 and R5; M with four branches, M3+4 forking far proximad of the bifurcation of M1+2; the 'bittacid cross’ aligned and gently curved, posterior part of the 'bittacid cross’ reaching M3 distad of the M3+4 forking point; one crossvein between R5 and M1, one between M1 and M2 and one between M2 and M3; Cu1 and Cu2 almost parallel with two crossveins between them, one crossvein between M4 and Cu1; 1A and 2A simple and one crossvein between them; 1A reaching the posterior margin at the same level of the origination of Rs from R1; 2A reaching the posterior margin at the same level of the origination point of M (Fig. 7C).

Hind wing. With the same shape as the forewing. R1 running smoothly through pterostigma; pterostigmal crossveins (Pcv) absent; Rs with four branches; one crossvein between R2+3 and R4 and one between R4 and R5; the 'bittacid cross’ aligned; M divided into three branches; two crossveins between R5 and M1, one between M1 and M2, one between M2 and M3 and one between M3 and Cu1; Cu1 and Cu2 parallel and with one crossvein between them. Vein 1A reaching the posterior margin at the level slightly proximad of the Rs originating from R1, one crossvein between Cu2 and 1A (Fig. 7D).

Abdomen. Abdomen 9.1 mm long, with ten visible segments. Female genital structure well-preserved from the dorsal view. Supraanale and cercus covered with small and short setae (Fig. 7A, B, E, F).

Remarks.

Exilibittacus foliaceus sp. n. (Fig. 7) is assigned to the genus Exilibittacus Yang, Ren & Shih, 2012 based on the following generic diagnostic characters: in forewing, Sc reaching the anterior margin proximad of the forking of R4+5 and the 'bittacid cross’ aligned; and in hind wing, Rs with four branches while M with three branches. Exilibittacus foliaceus sp. n. is distinguished from the other two species as shown by the key below.