Itaphlebia laeta

Liu, Nan, Zhao, Yunyun & Ren, Dong, 2010, Two new fossil species of Itaphlebia (Mecoptera: Nannochoristidae) from Jiulongshan Formation, Inner Mongolia, China, Zootaxa 2420, pp. 37-45 : 41-42

Itaphlebia laeta s p. nov.

( Figure 4 A–D, Figure 5 E–F)

Material. Holotype female, CNU-MEC-NN2009311-1 and CNU-MEC-NN2009311-2, positive and negative. Paratype, CNU-MEC-NN2009222-1 and CNU-MEC-NN2009222-2, positive and negative.

Horizon and locality. Jiulongshan Formation, Middle Jurassic, Daohugou Village, Ningcheng County, Inner Mongolia, China.

Diagnosis. Costal area narrow. In forewing, Sc simple, terminating at C near pterostigma; M with 4 branches; Cu1 and M forked before the cross-vein cu1-cu2.

Description. Antenna filiform, incompletely preserved. Femur shorter than tibia. Tibial spurs not present. Setae irregularly arranged.

Costal area narrow, one cross-vein c-sc between C and Sc. Sc simple, ending at C and extending to pterostigmal area. One short cross-vein sc2-r1 before pterostigma. Rs arised at the same level to cross-vein csc. Rs with 4 branches. Length of R2 two-thirds that of stem of R2+3. Cross-vein r1-r2 at level of pterostigma. Cross-vein r3-r4 at level of cross-vein r1-r2. Cross-vein r5-m1+2 approximately at middle of wing length. Crossvein r5-m1 proximal to cross-vein r4-r5. One cross-vein r4-r5 dividing cell R4 into 2 cells. Conspicuous thyridium at fork of M, which has 4 branches. M3+4 divided beyond the fork of M1+2; cross-vein m1+2-m3 between M1+2 and M3; cross-vein m-cu not straight, slightly S-shaped. Cu1 coalesced with M for a short distance and separated from M before cross-vein cu1-cu2. One cross-vein a1-a2 connected 1A and 2A. 3A absent.

Female abdomen with 11 segments, segments 9–11 smaller than segment 8. One pair of cerci located at apex of abdomen. Right cercus with 3 segments. Third segment of left cercus not preserved. Basal segments fused with abdomen segment 11.

Body length 7.8 mm, forewing length 8.2 mm, width 2.6 mm.

Etymology. From the Latin word laetus (clear), indicating venation is very clearly.

Remarks. The new species shows a similarity to Itaphlebia reducta but differs from the latter by location of the fork of R2+3 and length of R2 compared with R2+3.

Figures

FIGURE 4. Itaphlebia laeta sp. nov. A. Holotype, part CNU-MEC-NN 2009311 - 1; B. Holotype, counterpart CNU- MEC-NN 2009311 - 2; C. Paratype, part CNU-MEC-NN 2009222 - 1; D. Paratype, counterpart CNU-MEC-NN 2009222 - 2. All scales = 2 mm.

FIGURE 5. Itaphlebia laeta sp. nov., line drawings of holotype. A. Ventral view of body with wings; B. Left forewing.