Nannotanyderus oliviae Skibińska, Krzemiński & Coram, 2014

Skibińska, Kornelia, Krzemiński, Wiesław & Coram, Robert A., 2014, Discovery of the most ancient member of family Tanyderidae (Diptera) from the Lower Jurassic (Sinemurian) of England, Zootaxa 3857 (1), pp. 125-130 : 126-127

Nannotanyderus oliviae Skibińska, Krzemiński & Coram sp. nov.

( Figs. 2–5 )

Etymology. The new species name is dedicated to Olivia, daughter of Robert Coram.

Type material. Holotype No. I-F/MP/ 2/1621/13, complete wing; Paratype No. I-F/MP/ 1/1600/12, wing lacking anal lobe below A1 vein. Both from Brooki Bed, Shales-with-Beef Member, Charmouth Mudstone Formation, Lias Group (Lower Sinemurian, Turneri zone, Brooki subzone), Monmouth Beach, Lyme Regis, Dorset, UK (national grid reference SY 334 914).

Diagnosis. The new species differs from all other members of the genus in that veins Rs, R4+5 and R4 form a nearly straight line, and vein R4+5 is shorter than in other described species. It also differs from N. grimmenensis and N. ansorgei in that Sc terminates on the wing margin before fork of Rs into R2+3 and R4+5, from N. krzeminskii and N. kubekovensis in that m-cu is more distal to the fork of M3+4 into M3 and M4, and from? N. incertus in that Rs is shorter. The anal lobe is also more developed than in N. krzeminskii and N. ansorgei (not known in other species).

Description. Holotype. Wing length 2.8 mm. Sc short, extending half wing length, ending before fork of Rs into R2+3 and R4+5; R2+3 1.6 times longer than Rs and 2.6 times longer than R2; Rs as long as R3 and forming straight line with vein R4; R5 originates directly from R4 a short distance distal to its fork from Rs; vein M1 about 1.3 times longer than the upper edge of d cell; m-cu leaves M4 distal to the fork of M3+4 into M3 and M4. Explicit anal lobe.

Remarks. Although similar to other Nannotanyderus species, in particular N. krzeminskii , the observed wing venation differences and significantly older age (in excess of 12 Ma), justify the description of a new species for the English material.

Figures

FIGURE 2. Photography of the wing venation of Nannotanyderus oliviae sp. nov.; holotype (Lower Jurassic, Sinemurian). Scales 0.5 mm.

FIGURE 3. Photography of the wing venation of Nannotanyderus oliviae sp. nov.; paratype Scales 0.5 mm.

FIGURE 4. Reconstruction of the wing venation of Nannotanyderus oliviae sp. nov.; holotype (Lower Jurassic, Sinemurian). Scale 0.5 mm.

FIGURE 5. Reconstruction of the wing venation of Nannotanyderus oliviae sp. nov.; paratype (Lower Jurassic, Sinemurian). Scale 0.5 mm.