Proinogomphus kreuzerorum, Bechly, 2018

Bechly, Günter, 2018, First record and a new species of the fossil dragonfly genus Proinogomphus (Odonata: Liassogomphidae) from the Early Jurassic of Bascharage in the Grand Duchy of Luxembourg, Zootaxa 4450 (1), pp. 108-114 : 110-111

Proinogomphus kreuzerorum n. sp.

Figures 1–4

Holotype. Isolated complete hind wing of a female dragonfly with collection no. SMNS 67854 , deposited in the paleontological department at the State Museum of Natural History in Stuttgart ( Germany). The counter plate remains in private collection Kreuzer, but does not show any further details.

Type locality and horizon. Bascharage (49.6° N, 5.9° E: paleocoordinates 38.2° N, 14.8° E), south-west of the Grand Duchy of Luxembourg. “ Calcareous nodules” of the Schistes carton Formation ( Hermoso et al. 2014); Early Jurassic , Early Toarcian , Upper Liassic ( Lias epsilon), ca. 183 million years.

Etymology. A noun in the genitive case, named after Claudia and Frances Kreuzer (Trier, Germany), in appreciation of their kind donation of the holotype to the State Museum of Natural History Stuttgart.

Diagnosis. This species can be distinguished from the type species P. bodei by the following combination of characters: hind wing length only 35 mm (instead 45 mm), thus about 25% smaller; triangle and subtriangle free (instead of both crossed, with possible exception of the type specimen of P. aequalicellatus ); posttrigonal field with 2-3 rows of cells (instead strictly two rows until 8 cells distal of triangle); 8 branches of CuA (instead only about 5- 6); lestine oblique vein ‘o’ is 7 cells distal of subnodus (instead only about 5).

Description of holotype ( Figures 1-4 ). Well-preserved and complete isolated hind wing of a female dragonfly. Total length 35.2 mm, max. width 12.0 mm. Wing articulation with costal and radio-anal plates preserved. Only the primary antenodal crossvein ax1 is very distinct and 2.5 mm distal of basal brace ax0 (wing base), while ax2 is not clearly discernible in the fossil (either the fourth or rather the sixth antenodal distal of ax1); about 11 secondary antenodal crossveins in both rows, incl. several ones between ax1 and ax2. Space between RA and RP basal of subnodus regularly crossed by 11 antesubnodal crossveins (no cordulegastrid gap of antesubnodals near subnodus). Nodus at 44% of wing length; nodal veinlet n short and perpendicular; subnodal veinlet sn oblique. Nine postnodal crossveins non-aligned with the 9 postsubnodal crossveins beneath them; no libellulid gap of postsubnodal crossveins near subnodus. Pterostigma 4.3 mm long and max. 1.0 mm wide, elongate, with oblique sides and broadened margins; stigmal brace aligned with anterior margin of pterostigma, but not very oblique and strong; only 2 crossveins (3 cells) beneath pterostigma; 4 crossveins between C and RA distal of pterostigma. Primary IR1not developed; secondary IR2 originating 2 cells distal of pterostigma with a single row of cells between it and RP1; RP1 and RP2 distally divergent with 2-4 rows of cells between them; RP2 originates at subnodus; a single lestine oblique vein ‘o’ between RP2 and IR2 7 cells (4.9 mm) distal of subnodus. IR2 originating on RP3/4 (rather that RP1/2) a single cell distal of origin of RP3/4. No Rspl, but there is a single stronger intercalary vein distally branching from IR2. Midfork 7.7 mm distal of arculus; 10 antefurcal crossveins between RP and MA. RP3/4 and MA undulate and distally divergent with 2-4 rows of cells between them. Posttrigonal area between MA and MP with 2-3 rows of cells (in the area within 8 cells distal of triangle there are only 3 cell triplets, but 5 duplets); no Mspl, but there is a single stronger intercalary vein distally branching from MA. Between MP and CuA there is basally a short gap of crossveins; MP and CuA distally very divergent, with MP reaching far beyond level of nodus. CuA reaching to level of nodus with 8 posterior branches and 7 rows of cells in the cubital field. Anal vein with 4 posterior branches and 6 rows of cells in the anal field; anal margin rounded without anal angle or anal triangle. Arculus complete (closed) and broken (kinked), situated between ax1 and ax2, only 0.6 mm distal of ax1; hypertriangle very wide (2.7 mm long, max. width 0.7 mm), undivided, and quadrangular because trigonal vein ends distinctly below its distal angle; discoidal triangle transverse and undivided (length of basal side 1.5 mm, upper side 1.9 mm, distal side 2.1 mm); subdiscoidal vein parallel to CuPcrossing (= “anal crossing”) and delimiting a subdiscoidal cell, which is hardly developed as subtriangle. Basal space free. Wing hyaline without trace of color pattern, except for the dark pterostigma.

Figures

FIGURE 1. Photograph of the calcareous lens with the holotype SMNS 67854 of Proinogomphus kreuzerorum sp. nov. Scale bar = 20 mm.

FIGURE 2. Photograph of holotype SMNS 67854 of Proinogomphus kreuzerorum sp. nov. Scale bar = 5 mm.

FIGURE 3. Photograph of counter plate of the holotype of Proinogomphus kreuzerorum sp. nov., in private collection Kreuzer. Scale bar = 5 mm.

FIGURE 4. Drawing of Proinogomphus kreuzerorum sp. nov., holotype SMNS 67854, female hind wing. Scale bar = 5 mm.