Reisia guillaumei

Béthoux, Olivier & Anderson, John M., 2023, New light shed on Triadophlebiomorpha wing morphology and systematics (Insecta: Odonata), Geodiversitas 45 (17), pp. 479-496 : 486

Reisia guillaumei ( Grauvogel & Laurentiaux, 1952), n. comb.

( Fig. 2 )

Triadotypus guillaumei Grauvovel & Laurentiaux, 1952: 124 , figs 2, 3. — Nel et al. 2001: 503, figs 1-3.

Reisia gelasii Laurentiaux, 1958: 37 , text-figs 3, 4, pl. 1, fig. 2 (partim). — Bechly 1997: 53 (partim).

EXAMINED MATERIAL. — Holotype and only known specimen 7885/7886 (left wing in dorsal and ventral aspect, respectively; also referred to as ’57.32’ or ‘5732’ in the literature; Louis Grauvogel collection at the ‘Staatliches Museum für Naturkunde Stuttgart’, Stuttgart, Germany; Fig. 2 ).

TYPE LOCALITY AND STRATIGRAPHY. — Bust (Bas-Rhin, France); ‘Grès à Voltzia’ Formation; Anisian, Triassic; Gall & GrauvogelStamm 2005).

EMENDED DIAGNOSIS. — Width opposite the RP1/RP2 fork about 22 mm (lower in Reisia nana ); MP with 4 main posterior branches (in addition to its anterior stem; fewer branches in Reisia rubra n. comb.).

REMARKS

Our investigation revealed a number of discrepancies between previous descriptive accounts and what can be observed in the available material. Most importantly, the part that Nel et al. (2001) regarded as the base of MP (and Grauvogel & Laurentiaux [1952] as the base of CuP) turns out to be the pons, which is very long. Incidentally, it is strongly convex, which is inconsistent with an identification as (part of) MP. The course of the actual base of MP, although poorly preserved, yet is substantiated by a marked concave groove immediately posterior to the pons (black arrow on Fig. 2E, F ). Additionally, there is no evidence of a long RP+MA stem, as suggested by Nel et al. (2001). The corresponding area is not preserved in the side preserving the wing in dorsal aspect ( Fig. 2 ): only a very short section of the stem of RA (or R) is preserved, ending opposite the white arrow on Fig. 2E, F . The splitting plane then runs at the level of ScP, which is well exposed, with a short section of MA visible (i.e. RA and RP are embedded in the other side of the specimen). Further on, where preserved, RA (blue arrow on Fig. 1A, B ), RP and MA are clearly distinct. Quite unfortunately the corresponding area is totally missing in the side preserving the wing in ventral aspect (7886), probably as a consequence of rock splitting at the time of collection. Given our current knowledge of the wing morphology in triadophlebiomorphans, it is rational to assume that RP and MA run next to each other, but distinct, in Reisia guillaumei n. comb. ( Fig. 2A ; and see above).

Figures

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.

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.