Epicharmeropsis hexavenulosus Huang, Ren & Shih

Huang, Jiandong, Ren, Dong & Shih, Chungkun, 2007, New genus and species of Hexagenitidae (Insecta: Ephemeroptera) from Yixian Formation, China, Zootaxa 1629, pp. 39-50 : 41

Epicharmeropsis hexavenulosus Huang, Ren & Shih , sp. nov.

( Fig. 1–4 .)

Etymology. Latin prefix hexa- (six) and venulosus (veinlet).

Holotype. CNU-E-YX-2007001-1, CNU-E-YX-2007001-2 ( Fig. 1–3 ). Well preserved part and counterpart of imago; antennae and tarsi of middle and hind legs are not preserved; the Late Jurassic to the Early Cretaceous, Yixian Formation, Shimen Village, Yangshuling Township, Pingquan County, Hebei Province, China.

Material. Holotype and from the same locality, paratypes: male imago, No. CNU-E-YX-2007021-1, No. CNU-E-YX-2007021-2; male imago, No. CNU-E-YX-2007023; male imago, No. CNU-E-YX-2007024; male imago, No. CNU-E-YX-2007025-1, No. CNU-E-YX-2007025-2; female imago, No. CNU-E-YX- 2007004 ( Fig. 4 .).

Diagnosis. In addition to the diagnosis for the new genus, the species can be diagnosed as follows: CuA1 of forewing with 6 triads (loop-shaped veinlets) leading to wing margin.

Description. Male imago (dorsal view) ( Fig. 1–3 .).

Eyes relatively large, contiguous. Pterothorax well-developed; mesonotal suture (MNs) in anterior part of mesonotum strongly stretched backwards medially, not transverse; paired medioparapsidal sutures (MPs) jointed at middle area of mesonotum, not parallel; metanotum long, with evident scutum.

Forewing: broad and triangular with costal brace; costal margin slightly curved; tornoapical (outer) margin longer than basitornal (anal) margin; costal area relatively wide, narrowing toward tip; RA subparallel to SC; membrane slightly thickened at distal part of the field between C and RA; RSa formed two triads, RSp non-branched; MA branched after middle area of wing; MA1 and MA2 uniformly diverging; iMA approximated MA2; MP1 and MP2 diverged at an angle of approximately 30 degree; distinct intercalary veins existing between MP2 and CuA1; CuA bifurcated to CuA1 and CuA2, from the bifurcation a vein iCu formed 6 triads following one another: anterior branch of each triad forms next triad; each of these triads has anterior branch arched by its convexity anteriorly; all branches of these triads go to basitornal margin of wing.

Hind wing: broad with fairly obtuse tip; venation relatively profuse; the base of C strongly arched, far from SC; subcostal area broad, more than 3 times as wide as costal area; RA terminated near wing apex; RS formed triad RSa-iRS-RSp, RSa and RSp non-branched; MA bifurcated near middle; MP bifurcated near the base of wing; iMP approximated with MP1; CuA and CuP un-forked; more than 4 A present; anal area broad; numerous crossveins and intercalary veins near wing margin.

Legs (preserved): relatively sturdy and long; femora longer than tibia; three-segmented tarsi of fore legs preserved, slender; tarsi of middle and hind legs absent.

Abdomen: the posterolateral projections of the ninth segment, very long and sharp, nearly as long as the tenth abdominal tergum.

Paracercus, very short; cerci, long.

Female imago ( Fig. 4 .). Eyes relatively small, separate; mouth apparatus vestigial, only anterior margin of the frons forming a projected lamella; coxa, trochanter and femur of fore and middle legs preserved, sturdy; the posterolateral projections of the ninth segment not extended posterolaterally. Other characters are as in male.

Male and female subimagoes, and nymph are unknown.

Measurements (mm). Holotype: body length (excluding caudalii) 31.0 (head length 3.0, pronotum length 0.5, pterothorax length 9.5, abdomen length 18.0); forewing length 34.0, its width 14.0; hind wing length 18.0, its width 11.0; length of fore leg fragment 27.0 (femur 9.0, tibia 7.0, first tarsus 4.0, second tarsus 5.0, third preserved tarsus 2.0); femora of middle and hind legs 6.0; tarsi of middle and hind legs 5.0. Paratype: female imago No.CNU-E-YX-2007004, forewing length 34.0, its width 14.5.

Figures

FIGURE 1. Epicharmeropsis hexavenulosu s gen. et sp. nov., male imago, holotype: A, photograph of part CNU-E-YX- 200701 - 1; B, photograph of counterpart CNU-E-YX- 200701 - 2.

FIGURE 2. Epicharmeropsis hexavenulosu s gen. et sp. nov., male imago, holotype CNU-E-YX- 200701 - 1: A, photograph of head and thorax in dorsal view; B, photograph of cubital area on forewing. Without scale.

FIGURE 3. Epicharmeropsis hexavenulosu s sp. nov., male imago, holotype: A, body with wings, CNU-E-YX- 200701 - 1; B, forewing, CNU-E-YX- 200701 - 2.; C, hind wing, CNU-E-YX- 200701 - 2. MNs – mesonotal suture, MPs - medioparapsidal suture, LPs – lateroparapsidal suture.

FIGURE 4. Epicharmeropsis hexavenulosu s sp. nov., female imago, paratype CNU-E-YX- 2007004: A, photograph of paratype; B, body with wings on lateral view; C, forewing.