Epimesoplecia plethora, Lin, Xiuqin, Shih, Chungkun & Ren, Dong, 2015

Lin, Xiuqin, Shih, Chungkun & Ren, Dong, 2015, Revision of the genus Epimesoplecia Zhang, 2007 (Diptera, Nematocera, Protopleciidae) with five new species, ZooKeys 492, pp. 123-143 : 125

Taxon classification Animalia Diptera Protopleciidae

Epimesoplecia plethora sp. n. Figs 2, 3

Etymology.

The epithet of plethora is derived from the Greek word “plethore”, meaning “fullness”, emphasizing the body covered with dense pubescence. The specific epithet is a noun in apposition.

Diagnosis.

Compound eyes crescent. Antennae moniliform. Sc very close to the level of r-m; fork of Rs distad of fork of M1+2; Rs distad of crossvein r-m; bRs less than 2 times (1.6-1.8) as long as dRs, the latter about 3 times (2.6-3) as long as r-m; R2+3, sigmoidly curved, distinctly shorter than bRs and dRs combined; bM1+2 shorter than dM1+2; bM3+4 shorter than m-cu; cell bp as wide as cell ba terminally.

Material.

Holotype: Female. NO. CNU-DIP-NN2013202, a well-preserved almost complete body with left haltere, both wings and part of legs (Fig. 2A). Paratype: NO. CNU-DIP-NN2013209p/c, part and counterpart, lateral view, only right wing and legs preserved, head and abdomen incomplete (Fig. 3A, B).

Horizon and locality.

All specimens were collected from the Jiulongshan Formation, late Middle Jurassic age (Late Callovian) from Daohugou Village, Ningcheng County, Inner Mongolia Autonomous Region in China.

Description.

Head (Fig. 2D, F): Oviform. Compound eyes crescent in females. Antennae: scape and pedicel thick and stout, 1st flagellomere slender, the remaining ones becoming thinner toward apex.

Thorax (Figs 2A, 3A, B): Scutum convex; scutellum clearly projecting; haltere depressed.

Legs (Figs 2A, 3A, B): Forelegs comparatively thin and slender, femur slightly thicker than tibia, covered with dense setae as preserved. The 1st tarsomere 2 times as long as the 2nd tarsomere; the 3rd to 5th tarsi gradually thinned, claws small. Mid legs: femur long and slender, almost equal to tibia, tibial spurs minute, claws well-preserved. Hind legs: femur more than four-fifths of tibia; distinctly longer than forelegs and mid legs, tibia less than 2 times as long as femur; the 1st tarsomere more than 2 times as long as the 2nd tarsomere; with two pretarsal claws.

Wings (Figs 2A, C and 3A): Wing long and narrow, 2.6-2.8 times as long as width (length 8.4-9.0 mm, width 3.0-3.4 mm); Sc terminating at the middle of the anterior margin, the costal field narrow; bRs 4-5 times as long as r-m; R2+3 slightly sigmoidly curved; Rs arising from one-fourth of wing length, furcating distal level of fork of M1+2; stem of Rs longer than stem R, the former longer than R2+3; R4+5 weakly curved upward medially, ending just below apex of wing; both R4+5 and M1 subparallel; crossvein m-cu as long as r-m; CuA strongly curved, distad of M forking, ending at posterior margin of wing; A1 not preserved.

Female genitalia (Fig. 2E, G): The 8th segment slightly smaller than preceding segments, genitalia simple, with 2-segmented cerci, the basal segment of cerci thicker and longer than the terminal one.

Dimensions

(in mm). [Measurements for the paratype CNU-DIP-NN2013209p/c in brackets, if different]. Holotype: female. CNU-DIP-NN2013202, Body length 10 [5 as preserved], maximal width of body 2.2 [2.4]. Head length 0.6, width 0.8. Forelegs: femur 1.7 as preserved [2.2]; tibia 1.4 as preserved [3.4]. Mid legs: femur 3 [2.8], tibia 3.5 [3]. Hind legs: femur 3.6 [4], tibia 4.4 [5]. Wing: length 9.0 [8.2], width 3.4 [3.0], R2+3 2.4, bRs 2.2 [2.1], dRs 1.2, R4+5 3 [3.4].

Remarks.

The new species is differentiated from Epimesoplecia shcherbakovi Zhang, 2007 by the following features: bRs less than 2 times (1.6-1.7) as long as dRs (vs. bRs 4.5 times as long as dRs); Rs bifurcation distad to fork of M1+2 (vs. Rs bifurcation at the same level of fork of M1+2); dM1+2 longer than bM1+2 (vs. dM1+2 shorter than bM1+2). The new species differs from Epimesoplecia elenae Zhang, 2007 in having antennae moniliform (vs. filiform); bRs short, less than 2 times (1.6-1.7) as long as dRs (vs. bRs long, 2.5 times as long as dRs); bM3+4 clearly shorter than m-cu (vs. bM3+4 as long as m-cu). Comparisons with other species are listed in Table 1.