Reisia Handlirsch, 1912

Béthoux, Olivier & Anderson, John M., 2023, New light shed on Triadophlebiomorpha wing morphology and systematics (Insecta: Odonata), Geodiversitas 45 (17), pp. 479-496 : 483-484

Genus Reisia Handlirsch, 1912

Reisia Handlirsch, 1912: 6 . — Type species: see below.

Handlirschia Reis, 1909: 677 .

Triadotypus Grauvogel & Laurentiaux, 1952: 124 . — Type species: Triadotypus guillaumei Grauvogel & Laurentiaux, 1952 .

Rabru Béthoux, De la Horra, Benito, Barrenechea, Galán & López-Gómez, 2009: 182 . — Type species: Rabru rubra Béthoux, De la Horra, Benito, Barrenechea, Galán & López-Gómez, 2009 , n. syn.

TYPE SPECIES. — Handlirschia gelasii Reis, 1909 by monotypy.

DIAGNOSIS. — RP1/RP2 fork and point of origin of the first I- in the area between RP3+4 and MA opposite each other, or nearly so (known in Reisia gelasii , Reisia guillaumei n. comb. and Reisia rubra n. comb.); pons very long (known in Reisia guillaumei n. comb. only); RP/MA fork in a more basal position than the MP/Cu+AA fork (known in Reisia guillaumei n. comb. only); at its origin, Irp 1 -rp 2 closer to RP2 than to RP1 (known in Reisia guillaumei n. comb. and Reisia rubra n. comb.); first I- in the RP3+4 area well-developed, dichotomously branched (known in all species); in its distal part, MP with 4 main posterior branches (in addition to the ending of its main stem; known in Reisia gelasii and Reisia rubra n. comb., assumed in Reisia guillaumei n. comb.; probably fewer branches in Reisia rubra n. comb.); in the area between the first and second posterior branches of CuA, occurrence of a well-developed, branched I- (known in Reisia guillaumei n. comb. and Reisia rubra n. comb.); CuP rectilinear (as opposed to curved or sigmoidal), with two main stems, both branched, with a well-formed I+ between them (known in Reisia guillaumei n. comb. and Reisia rubra n. comb.); AA (or, anterior branch of) rectilinear (as opposed to curved or sigmoidal; known in Reisia guillaumei n. comb. and Reisia rubra n. comb.); area between AA and the posterior wing margin, basal to the pons, lobe-shaped and filled with poorly organized veinlets, some directed backwards (known in Reisia guillaumei n. comb. only; possibly a feature proper to the hindwing).

OTHER SPECIES. — Reisia guillaumei ( Grauvogel & Laurentiaux, 1952) , n. comb., Reisia nana ( Laurentiaux-Vieira, Ricour & Laurentiaux, 1952) and Reisia rubra ( Béthoux, De la Horra, Benito, Barrenechea, Galán & López-Gómez, 2009) , n. comb.

REMARKS

Whether a number of triadophlebiomorphan species should be included, or not, in this genus, remained a conundrum for decades due to the incompleteness of the available material on one hand, and inadequate data on some of its potential relatives. Preliminarily, in the holotype of Reisia gelasii , circular elevations with a puncture in their middle occur in the area between RP1 and RP2 [at least in its basal part; noted by Reis (1909) as ‘pores’; see Fig. 1E, F ]. This is unique among triadophlebiomorphans but might have been overlooked and/ or may be poorly preserved in other members of this taxon. Indeed, similar structures were observed by Carpenter (1947) in Permian, large-sized meganisopterans. According to this author, they might represent setal bases. The occurrence and distribution of these structures would need a better documentation for their systematic relevance to be properly assessed. Our new data and observations led us to concur withBechly (1997; and see Grauvogel & Laurentiaux 1952) that the genus Triadotypus Grauvogel & Laurentiaux, 1952 must be regarded a junior synonym of Reisia Handlirsch, 1912 . Indeed, as far as preserved, the respective holotypes (and only known material) of the type-species of each genus ( Reisia gelasii [ Fig. 1 ] and ‘ Triadotypus ’ guillaumei [ Fig. 2 ]) are nearly identical, including size (width opposite the RP1/RP2 fork, 22.0 mm and about 22.4 mm, respectively), but for: i) the RP1/RP2 fork and the point of origin of the first I- in the RP3+4, both located in a slightly more basal position in Reisia gelasii ; and ii) a higher density of cross-veins in the median part of the wing in Reisia gelasii . Such traits are best regarded as of specific relevance. Among characters advocated by Nel et al. (2001) to maintain Reisia and Triadotypus as distinct genera, only the branching pattern of MP (or lack thereof) is preserved in both holotypes. Even though the holotype of ‘ Triadotypus ’ guillaumei is comparatively poorly preserved in the corresponding area, the course of the CuA distal-most branch suggests that MP indeed possesses genuine posterior branches, as in Reisia gelasii . Another notable point is that in ‘ Triadotypus ’ nana , consistently regarded as closely related to ‘ Triadotypus ’ guillaumei by previous authors (including Nel et al. 2001), MP clearly has several posterior branches.

We further noted unexpected similarities between Reisia guillaumei n. comb. and ‘ Rabru ’ rubra . Even if the latter is known from a fragmentary, single wing, its wing venation matches, in nearly every aspect, that of Reisia guillaumei n. comb., including the organisation of CuP, provided with two main stems and an I+ between them. Both species are also very similar in size (width opposite the RP1/RP2 fork about 21.4 mm in ‘ Rabru ’ rubra ). We therefore propose to assign ‘ Rabru ’ rubra to the genus Reisia . One notable point regards the number of MP and CuA branches, lower in Reisia rubra n. comb. than in any other species herein assigned to Reisia . This trait is considered as of specific relevance. As for Reisia nana ( Laurentiaux-Vieira, Ricour & Laurentiaux, 1952) , known from a very fragmentary, single wing, there are virtually no differences between it and Reisia guillaumei n. comb., apart from a distinctly smaller size (judging from the morphology of the latter, wing width is about 14.0 mm opposite the RP1/RP2 fork in Reisia nana ), which justifies maintaining the species ( Bechly 1997).

The assignment of ‘ Triadotypus ’ sogdianus Pritykina, 1981 to the genus Reisia , provisionally proposed by Nel et al. (2001), is dubious, as this species has (compared to Reisia species for which the corresponding traits are documented): i) the first fork of the first I- in the area between RP3+4 and MA area located more basally; ii) a more developed MP; and iii) curved CuP and AA. This species should probably be assigned to a genus on its own. The case of ‘ Reisia ’ rieki Deregnaucourt, Wappler, Anderson & Béthoux, 2017 will be addressed below.

In summary, available evidence points towards marked similarities between Reisia gelasii , Reisia guillaumei n. comb., Reisia rubra n. comb. and Reisia nana . Yet, it must be acknowledged that most of these species are known from fragmentary material. Future discoveries might reveal unforeseen differences, making it necessary to reinstate some of the genera herein regarded as junior synonyms of Reisia .

Figures

FIG. 1. — Reisia gelasii (Reis, 1909), holotype, specimen SNSB-BSPG 1908 I 49 (‘Bayerische Staatssammlung für Paläontologie und Geologie’, Munich, Germany), right wing in dorsal aspect: A, B, overview; A, drawing of venation (small blue arrow, ending of RP3+4; small green arrows indicating the termination of CuA branches); B, photograph; C-F, details, locations as shown on B, photographs extracted from RTI file (D, F, under normals visualisation); C, area posterior to RP3+4, the origins of paired convex and concave intercalaries (I+ and I-) become increasingly concave from the distal to the proximal areas; D, detail of the ‘MP-CuA twilight zone’ (nature of structures encircled in white discussed in the text); E, F, detail of presumed setal bases (large white arrows indicating the best preserved ones). Scale bars: A, B, 10 mm; C, D, 5 mm; E, F, 2 mm.

FIG. 2. —Reisia guillaumei (Grauvogel & Laurentiaux, 1952),n. comb.,holotype,specimen 7885 (collection Louis Grauvogel at the ‘ Staatlisches Museum für Naturkunde Stuttgart’,Stuttgart,Germany), left wing: view; A, drawing of venation (large blue arrow indicating the only portion of RA preserved between the pons and the nodus; small green arrows indicating the termination of CuA branches); B, photograph of fragment, dorsal aspect (flipped horizontally); C, photograph of the distal fragment, dorsal aspect (flipped horizontally); D-F, detail of the wing base, location as shown on B; drawing of venation (enlargement from added color-coding); E, F, photographs extracted from RTI file (F, under normals visualisation; large white arrow indicating the end of the preserved section of the adjoined R and MA [or RA and RP+MA]; large row indicating the course of MP below the pons). Scale bars: A-C, 10 mm; D-F, 4 mm.