Turanopteron sinensis Huang & Nel, 2023

Huang, Di-Ying, Xu, Min-Min, Zhao, Qian, Gao, Jian & Nel, André, 2023, New stem-anisopteran dragonflies in the Jurassic of China (Odonata: Epiproctophora), Zootaxa 5396 (1), pp. 26-34 : 28-29

Turanopteron sinensis Huang & Nel sp. nov.

urn:lsid:zoobank.org:act:54CEA447-CF9C-4155-BF76-D2A33FDF9BB1

Figure 2

Etymology. Named after Sinica, Latin name for China.

Material. Holotype NIGP202928 (a nearly complete forewing, with extreme base and apex missing), housed in the Nanjing Institute of Geology and Palaeontology, CAS, Nanjing, China.

Age and outcrop. Earliest Late Jurassic (Oxfordian); uppermost part of Yangshuzhuang Formation near Anyao Village, Chengliu Township, Jiyuan City, Henan Province, China.

Diagnosis. Forewing characters. Forewing ca. 19–20 mm long; stem of RP basad midfork four cells long; long intercalary veins in areas between RP3/4 and IR2 and between MAa and RP3/4; one row of cells in cubital area; MAa and IR2 weakly zigzagged.

Description. Preserved part of wing 18.3 mm, wing ca. 20.0 mm long, 4.5 mm wide, possibly infuscate; pterostigma 0.8 mm long, 0.4 mm wide, covering one-two cells; no oblique pterostigmal brace; distance between nodus and pterostigma 8.0 mm, between wing base and arculus ca. 2.3 mm, between arculus and nodus 7.3 mm, between wing base and Ax1 1.5 mm, between Ax1 and Ax2 2.1 mm; Ax1 and Ax2 of inverted obliquity; no secondary antenodals in area between C and ScP, ca. six secondary antenodals of second row; ca. eight subantenodal crossveins; no crossvein in area between RP and MAa basad midfork; stem of RP four cells long; discoidal space basally open; MAb close arculus; one row of cells in anal area; AA+CuP no distally fused with MP+CuA; MP and CuA separating at level of apex of MAb; area between MP and CuA basally narrower than postdiscoidal area, CuA rather long, without well-defined posterior branches and one row of cells between it and posterior wing margin; area between MP and posterior wing margin broad, with two rows of cells; postdiscoidal area with one row of cells strongly narrowed distally; MAa basally straight and distally weakly zigzagged; area between MAa and RP3/4 distally broadened with five secondary veinlets in-between; area between RP3/4 and IR2 with a secondary zigzagged longitudinal vein in-between; IR2 very weakly zigzagged distally; one secondary longitudinal vein in area between IR2 and RP3/4; no antefurcal crossvein basal of midfork; nodal crossing and subndus aligned; base of RP2 two cells distad subnodus; no oblique crossvein ‘O’; area between IR2 and RP2 narrow with one row of cells; IR1 well defined, with two rows of cells and a strong secondary longitudinal vein between it and RP2; one-two rows of cells between IR1 and RP1; nine postnodal crossveins not well aligned with seven postsubnodal crossveins.

Remarks. This nearly complete forewing can be attributed to the Isophlebioptera because it shows the following putative synapomorphies: RP3/4 parallel to IR2; space between RP3/4 and MAa distinctly expanded and traversed by four long convex ‘secondary branches’ of RP3/4; postdiscoidal space between MP and MA very narrow, with only one row of cells between them; CuAa shortened and postero-distally indistinct (zigzagged); distal space between MP and CuAa strongly expanded; distal of Ax2 all antenodal crossveins between costal margin and ScP suppressed. An attribution to the Euthemistidae Pritykina, 1968 is unlikely because the new fossil has only one secondary longitudinal vein between RP3/4 and IR2, and between RP2 and IR1, no secondary antenodals vs. numerous, and base of RP2 well distad subnodus vs. opposite it ( Nel et al. 1993; Li et al. 2013). The Selenothemistidae Handlirsch, 1939 currently comprise the genera Selenothemis Handlirsch, 1920 , Turanothemis Pritykina, 1968 , Caraphlebia Carpenter, 1969 , Sinothemis Huang et al., 2018 , Jurathemis Huang et al., 2019 , and maybe also Paraliassophlebia Hong, 1983 ( Bechly 2016; Kelly & Nel 2018; Huang et al. 2018b, 2019). Selenothemis , Turanothemis , Caraphlebia , Sinothemis , and Jurathemis strongly differs from the new fossil in the very broad area between RP3/4 and IR2 ( Pritykina 1968; Nel et al. 1993; Kelly & Nel 2018; Huang et al. 2018b, 2019). The Isophlebiida Bechly, 1996 have much more intercalary ‘branches’ of MP distad apex of CuA than in the new fossil.

The base of RP2 situated well distad subnodus is a putative synapomorphy of the Parazygoptera. Affinities with the Sphenophlebiidae Bechly, 1997 are excluded because the new fossil has only one intercalary longitudinal vein between RP3/4 and IR2 instead of three-four ( Bode 1953: pl. 1, fig. 8; Nel et al. 1993: fig. 76; Nel & Jarzembowski 1996: figs 5–7). The absence of ‘antefurcal crossvein in the space between RP and MA basad midfork’ is a putative synapomorphy of the Euparazygoptera Bechly, 1997 (= Enigmalestidae Nel & Huang, 2021 , Asiopteridae Pritykina, 1968, Triassolestoidea Tillyard, 1918). The Triassolestoidea differ from the new fossil in the nodal and subnodal veinlets not aligned and separated by a short kink in RA. The Enigmalestidae strongly differ from the new fossil in the veins AA+CuP and MP+CuA partly fused basal of Arc; AA re-emerging from MP+Cu at level of basal closure of discoidal cell and ending at posterior wing margin without being in contact with distal free part of CuA; base of RP2 slightly distal to subnodus ( Nel & Huang 2021).

The Asiopteridae are characterized by two characters present in the new fossil, viz. IR2 distally zigzagged, and MA distally zigzagged; plus the hind wing character discoidal cell secondarily more quadrangle-like, thus with an oblique distal side MAb, unknown in the new fossil. Oreopteron Pritykina, 1968 , Oreopterella Pritykina, 1968 , and Asiopteron Pritykina, 1968 would differ from the new fossil in the short stem of RP basad midfork, only one-two cells long vs. four cells, but this character is proper to the hind wings, while the forewings of the Asiopteridae have an elongate stem of RP, as visible in Oreopterella ( Pritykina 1968: fig. 6). As they are preserved, it is nearly impossible to accurately justify the separations between Asiopteron and Oreopteron on one side, based on hind wings, from the Turanopteron spp. , on the other side, based on forewings.

Amblyopteron breve Pritykina, 1980 , Sogdopteron elongatum Pritykina, 1980 , Sogdopteron leve Pritykina, 1980 , Pauropteron exile Pritykina, 1980 , and Pauropteron miserum Pritykina, 1980 strongly differ from the new fossil in the absence of intercalary longitudinal veinlet between RP3/4 and IR2 ( Pritykina 1980: figs 124–126). Chrismooreia michaelbehei Bechly, 2018 has much longer wings than the new fossil, with a distinctly denser venation ( Bechly 2018: fig. 4).

The new fossil strongly resembles the forewings currently attributed to Turanopteron ( T. minor , T. medium , T. major , and T. pommerana ) ( Pritykina 1968; Ansorge 1996). It differs from T. pommerana in the shorter stem of RP basad midfork, only four cells long vs. six cells in the latter. Turanopteron minor has shorter intercalary veins in areas between RP3/4 and IR2 and between MAa and RP3/4. Turanopteron medium also has a short intercalary vein in areas between RP3/4 and IR2, if those in area between MAa and RP3/4 are of comparable length with the situation in the new fossil. The situation in T. major is unknown but it differs from the new fossil in the presence of two rows of cells in cubital area vs. one in the new fossil. The new fossil is a forewing ca. 19–20 mm long, compatible with T. medium that has a forewing 21 mm long, while it is 14 mm long in T. minor , and 31 mm in T. major . Turanopteron bexleyi is based on an incomplete hind wing from the Lower Cretaceous of UK. It also shows the difference between the fore- and hind wings in the length of the stem of RP, present in the other species of Asiopteridae . Its MAa and IR2 are more strongly zigzagged than in the new fossil ( Nel & Jarzembowski 1996: fig. 8).

Figures

FIGURE 2. Turanopteron sinensis Huang & Nel, sp. nov., holotype NIGP202928, forewing. a, photograph; b, drawing. Scale bars = 2 mm.