Mongoliaeshna sinica sp. n.

After Mongolia and Aeshna.

Mongoliaeshna differs from Progobiaeshna liaoningensis Bechly et al. (2001) in the anal loop divided into five cells instead of nine cells, forewing vein PsA angled with three cells in subdiscoidal space instead of two, basal part of area between MP and CuA with a longer zone with two rows of cells in hindwing, and basal part of area between RP1 and RP2 with two rows of cells just distal of second oblique vein, as in Gobiaeshna occulta Pritykina, 1977. Mongoliaeshna differs from this latter taxon in the subdiscoidal space three-celled. A further difference with both Progobiaeshna and Gobiaeshna is the free hypetriangle in Mongoliaeshna, instead of being crossed by two or three cross-veins.

Mongoliaeshna sinica sp. n. (Fig. 1, Fig. 2, Fig. 3, Fig. 4 and Fig. 5).

Head 2.8 mm long, 3.0 mm wide, with eyes meeting for about 2 mm long; thorax 8.0 mm long, 6.0 mm wide; four abdominal segments preserved, no expanded lobed on abdominal segments 3 and 4, unlike in Cymatophlebia species (Bechly et al., 2001).

Wings hyaline; forewing 45.0 mm long, 11.3 mm wide; distance from base to arculus 5.0 mm; from arculus to nodus 15.0 mm; from arculus to base of RP3/4 9.3 mm; no secondary antenodal cross-vein basal of Ax1, at least two antenodal cross-veins of first row and one of second row between Ax1 and Ax2, nine of first row and nine of second row distal of Ax2; distance from wing base to Ax1 3.6 mm, between Ax1 and Ax2 4.5 mm; Ax2 basal of apex of discoidal triangle; RP and MA strongly separated in arculus; hypertriangle 4.5 mm long, 0.9 mm, free; discoidal triangle 0.7 mm distal of arculus, divided into five smaller cells, elongate, with basal side 2.3 mm long, anterior side 3.8 mm long, and MAb 4.1 mm long; no angle in MAb and no convex trigonal planate; postdiscoidal area with 3-4 rows of cells; no Mspl; no pseudo-ScP distal of nodus; basal part of area between RA and RP with five cross-veins basal of RP3/4, and four distal of base of RP3/4 and basal of subnodus; area between RP and MA with ten cross-veins basal of RP3/4; two oblique veins ‘O’, first two cells distal of base of RP2 and second six cells distally; RP2 with a weak curve just basal of pterostigma; IR2 with a weak curve; 1-2 rows of cells between RP2 and IR2; area between RP1 and RP2 basal of pterostigma narrow but with two rows of cells; pseudo-IR1 very short; Rspl well defined with three rows of cells between it and IR2; RP3/4 and MA with a weak double curve and with space between them widened near posterior wing margin; pterostigma rather short, 3.8 mm long, 0.9 mm wide, covering four cells; pterostigmal brace not very oblique but aligned with basal side of pterostigma; 13 postnodal cross-veins not aligned with 17 postsubnodal cross-veins; 1-2 rows of cells between MP and CuAa; median area free; submedian area crossed by CuP-crossing; subdiscoidal space divided into three cells; PsA angled; two rows of cells between AA and posterior wing margin; cubito-anal area broad, with seven rows of cells between CuAa and posterior wing margin; CuAa with six posterior branches.

Hindwing 50.4 mm long, 14.3 mm wide; distance from base to arculus 5.2 mm; from arculus to nodus 13.2 mm; from arculus to base of RP3/4 7.5 mm; no secondary antenodal cross-vein basal of Ax1, at least two antenodal cross-veins of first row and two of second row between Ax1 and Ax2, four of first row and four of second row distal of Ax2; distance from wing base to Ax1 3.8 mm, between Ax1 and Ax2 5.7 mm; Ax2 opposite apex of discoidal triangle; RP and MA strongly separated in arculus; hypertriangle 4.3 mm long, 1.0 mm, free; discoidal triangle 0.9 mm distal of arculus, divided into five smaller cells, elongate, with basal side 2.0 mm long, anterior side 3.4 mm long, and MAb 4.3 mm long; no angle in MAb and no convex trigonal planate; postdiscoidal area with four rows of cells; no Mspl; no pseudo-ScP distal of nodus; basal part of area between RA and RP with three cross-veins basal of RP3/4, and three distal of base of RP3/4 and basal of subnodus; area between RP and MA with four cross-veins basal of RP3/4; two oblique veins ‘O’, first two cells distal of base of RP2 and second five cells distally; RP2 with a weak curve just basal of pterostigma; IR2 with a weak curve; 1-2 rows of cells between RP2 and IR2; area between RP1 and RP2 basal of pterostigma narrow but with two rows of cells; pseudo-IR1 very short; Rspl well defined with three rows of cells between it and IR2; RP3/4 and MA with a weak double curve and with space between them widened near posterior wing margin; pterostigma rather short, 4.7 mm long, 0.9 mm wide, covering four cells; pterostigmal brace not very oblique but aligned with basal side of pterostigma; 13 postnodal cross-veins not aligned with 16 postsubnodal cross-veins; two rows of cells between MP and CuAa; median area free; submedian area crossed by CuP-crossing; subdiscoidal space crossed by one cross-vein, PsA nearly straight; posterior wing margin angular at base with a long three-celled anal triangle (male specimen); anal area broad, with two posterior branches of AA directed towards posterior wing margin, and eight rows of cells between AA and posterior wing margin; anal loop rather small, not elongate, pentagonal, posteriorly closed, divided into five cells; cubito-anal area broad, with ten rows of cells between CuAa and posterior wing margin; CuAa with seven posterior branches.

Holotype specimen NIGP 140800 (print and counterprint of a body with two complete wings and bases of the two other wings attached), housed in Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, China.

Liutiaogou Village, Ningcheng County, Inner Mongolia, NE China.

Lower Cretaceous, Yixian Formation.

Named after Sinica, Latin name for China.