Sinoelmoa yangquanensis Yang, Cui, Xu & Béthoux, 2024

Yang, Nan, Cui, Yingying, Xu, Ziqiang, Xu, Yanqi, Ren, Dong & Béthoux, Olivier, 2024, The first Permian Diaphanopterodea (Insecta, Megasecopteromorpha) from China, Fossil Record 27 (2), pp. 247-258 : 247-258

Sinoelmoa yangquanensis Yang, Cui, Xu & Béthoux sp. nov.

Fig. 4

Type material.

YQZYW 15 , part and counterpart .

Etymology.

Named after the Yangquan city where the Shuiquan Gully locality is located.

Type locality.

The specimen was collected at the Shuiquan Gully locality; Shanxi Formation, Permian, Cisuralian, Asselian (Shen S. et al. 2020; Shen B. et al. 2022); near Yangquan City, Shanxi Province, China.

Diagnosis.

Area between anterior wing margin and R / RA dark; ScP vanishing in the area between anterior margin and R / RA; MA / MP split opposite the RA / RP split (as opposed to MA / MP split well distal of RA / RP split); CuP forked; AA long (as opposed to AA short), ending on posterior margin beyond wing mid-length.

Description.

Positive and negative imprints of a right forewing, distal part missing; dark area between anterior margin and R / RA; near wing base, preserved anterior wing margin very oblique, suggestive of the presence of a short portion of ScA distinct from the anterior wing margin (see Fig. 4 A ); ScP vanishing in the area between the anterior wing margin and RA, just beyond the brief RP-MA connection; stem of R + M convex, with a distinct inflexion opposite the point of separation of R and M (located about 3.6 mm distal from wing base); RA convex, simple and strong, parallel to anterior wing margin; RP posteriorly pectinate, with 3 simple branches preserved; MA / MP split opposite the RA / RP split; MA diverging anteriorly and then shortly connected with RP; MA simple; MP forked distally; short Cu stem visible; CuA diverging anteriorly from Cu, then close and parallel to R + M stem for some distance, suddenly diverging posteriorly, slightly basal to the R / M split; CuA simple; CuP forked distally; CuA – CuP area narrow until the first cross-vein occurring in this area, which is short and strong, located slightly distal to MA / MP split; anal area very well-developed, with a total of eight terminal branches (anterior-most branch, presumably AA, with 3 terminal branches); cross-veins difficult to observe, evenly distributed over the whole wing, forming two gradate series.

Measurements.

Preserved wing length 15.4 mm, width 5.5 mm.

Systematic placement.

The presence of a very short cua-cup cross-vein allows assigning the new specimen to the Diaphanopterodea and, within this taxon, allows excluding affinities with the Sinodiaphidae . Furthermore, the derived state ‘ long fusion of CuA with R + M (or, CuA running very close to R + M for some distance) ’ allows excluding the new material from the Diaphanopteridae . Then, an assignment to the Parelmoidae as delimited above is straightforward. Nevertheless, a possible assignment to the family Elmoidae was also considered. Two main character states allow distinguishing members of this family (Fig. 3 ) from the Parelmoidae (Fig. 2 ), namely (1) an anal area narrow, with a simple AA (Fig. 3 A, B, C, E ), sometimes with a short AP-like vein (Fig. 3 D, F ) (as opposed to a well-developed anal area, with numerous long veins, in Parelmoidae ); and (2) ScP terminating on RA near the basal third of the wing length (as opposed to distal to the wing mid-length, in Parelmoidae ). Even though the termination of ScP is not visible in the new material, it is clearly not directed towards RA at the point where it vanishes, which is already distal to the point where it reaches RA in Elmoidae . The assignment of our new material to the Elmoidae can therefore be excluded.

Within the Parelmoidae , the extent of the AA area is a useful character to consider first. This area is distinctively long in the new material, a state shared with Elmodiapha (see Kukalová-Peck 1974, text-figs 1, 2), from Obora ( Czech Republic; Cisuralian, Sakmarian), and Parelmoa (Fig. 2 A – D ) and Pseudelmoa (Fig. 2 E ), from the Elmo & Midco localities (Kansas, Oklahoma, USA; Cisuralian, Artinskian). However, the MA / MP split is located well distal of the RA / RP split in these three genera, whereas they are at the same level in new material. The new material further differs from Parelmoa , Pseudelmoa and Elmodiapha by the brief connection of RP and MA (the two veins are distinct in the three genera) and the presence of a forked CuP (this vein is simple in the three genera). Incidentally, in addition to differences in the extent of the AA area, the same characters allow excluding affinities with the genus Permuralia (Fig. 2 F ; Chekarda, Russian Federation; Cisuralian, Kungurian; and see Kukalová-Peck and Sinichenkova 1992), in which RP and MA are fused for a more or less long distance, and CuP is simple.

Permelmoa magnifica Prokop & Nel, 2011 , from the Lodève locality ( France; Cisuralian, Kungurian), is also currently assigned to Parelmoidae . To better assess the affinities of the new material we carried out new observations of the material of this species (Fig. 5 ; and see Yang et al. 2024). In contrast with Prokop and Nel (2011), we observed that (i) RP has four branches (as opposed to three); that (ii) CuA runs close to (or is fused with) R + M for a short distance, and then sharply diverge posteriorly from the R + M stem, just basal of the first split of this stem, a character generally occurring in Parelmoidae (Fig. 2 ) and Elmoidae (Fig. 3 ) (and see Carpenter 1943, 1947, 1992); that (iii) the first fork of MP is located distally [the basal portion of the stem regarded by Prokop and Nel (2011) as the first posterior stem of MP (long dotted line on Fig. 5 A ) is herein regarded as a twin, shifted impression of CuA, because (i) the apical part of the wing is preserved as a shifted impression, on a layer different from the rest of the wing (Fig. 5 A ), (ii) the elevation of this vein portion is inconsistent with an assignment to MP and (iii) such twin imprints have already been documented for Lodève material ( Béthoux et al. 2007: p. 185; and O. B. pers. obs.) but also from other fossil localities (e. g., see Béthoux 2015); it may be the consequence of delamination and then shifting of the two epidermic layers composing the wing, or of multiple impressions implying a release from the sediment, displacement, and second impression of a single wing, a phenomenon yet to be demonstrated experimentally], this being consistent with previous reports on the wing morphology of Parelmoidae and Elmoidae (Figs 2 , 3 ; and see Kukalová-Peck 1974); and (iv) despite a very incomplete preservation, it can be assessed that CuA and CuP, distal to their respective origins, approximate each other before departing, and are therefore most likely connected by a short, oblique cua-cup cross-vein known in Diaphanopteridae , Parelmoidae and Elmoidae (see above). Additionally, we propose homology conjectures alternative to those followed by Prokop and Nel (2011) regarding the MA / MP split. These authors adopted a traditional interpretation (Fig. 5 B ) involving a free stem of M splitting into MA and MP near the origin of RP. However, this implies the presence of a very strong, oblique cross-vein between RA and RP (* on Fig. 5 B ), unknown in other Parelmoidea and Elmoidae . A possible alternative interpretation (Fig. 5 C ) predicts that the MA / MP split occurs at the point where R and M diverge, and that MA runs fused with R for some distance. The ‘ strong oblique cross-vein’ can then be interpreted as the base of RP (* in Fig. 5 C ). Incidentally, RP and MA are then connected by a strong cross-vein, as is commonly the case in Parelmoidae and Elmoidae . However, the first cross-vein in the MA – MP area is then located in a more basal position than is usually the case in these families, but this can be legitimately related to the more basal position of the MA / MP split. It must be emphasized that a R + MA common stem has already been advocated for Permuralia sharovi ( Kukalová-Peck and Sinichenkova 1992) (although a free base of MA is still present) and is admitted for several other members of the order Diaphanopterodea (see Prokop and Kukalová-Peck 2017: text-figs 4, 6; and in Asthenohymenidae Tillyard, 1924 and Martynoviidae Tillyard, 1932 ). Following this interpretation, and in conjunction with a very long ScP, Permelmoa magnifica stands out as a very unique Parelmoidae . Regardless of the favoured interpretation on the course of MA, the new material differs from Permelmoa magnifica in many respects, including the respective position of the RA / RP and MA / MP split, the extent of ScP, and the extent of the AA area.

In summary, it is legitimate to erect a new genus and species for the new material.

Figures

Figure 2. Wing venation of representatives of Parelmoidae Rohdendorf, 1962. A – D. Representatives of the genus Parelmoa Carpenter, 1947. A. Parelmoa revelata Carpenter, 1947, holotype, specimen MCZ 4822, drawing of right forewing and photograph (positive imprint, light-mirrored). B, C. Parelmoa radialis Carpenter, 1947. B. Holotype, specimen MCZ 4825, drawing of left forewing and photograph (negative imprint, flipped horizontally, light-mirrored). C. Paratype, specimen MCZ 4824, drawing of left forewing and photograph (negative imprint, flipped horizontally). D. Parelmoa obtusa Carpenter, 1947, holotype, specimen MCZ 4823, drawing of left forewing and photograph (composite of both sides). E. Pseudelmoa ampla Carpenter, 1947, holotype, specimen MCZ 4826, drawing of right forewing and photograph (positive imprint). F. Permuralia maculata (Kukalová-Peck & Sinichenkova, 1992), paratype, specimen PIN 1700 / 492, drawing of right forewing and photograph (negative imprint). Photographs of MCZ material, Museum of Comparative Zoology, Harvard University, © President and Fellows of Harvard College, CC BY-NC-SA 4.0; photograph of PIN specimen, courtesy A. Felker.

Figure 3. Wing venation of Elmoa trisecta Tillyard, 1937 (Elmoidae Tillyard, 1937). A. Specimen MCZ 4590, drawing of left forewing and photograph (negative imprint, reversed, light-mirrored). B. Specimen MCZ 4593, drawing of right forewing and photograph (negative imprint, light-mirrored). C. Specimen MCZ 4606, drawing of right forewing and photograph (negative imprint, flipped horizontally). D. Specimen MCZ 4592, drawing of right forewing (positive imprint). E. Specimen MCZ 4591, drawing of wings and photograph (positive imprint). F. Specimen MCZ 4594, drawing of left forewing and photograph (positive imprint). Abbreviations: LFW, left forewing; LHW, left hind wing; RFW, right forewing; RHW, right hind wing. All photographs, Museum of Comparative Zoology, Harvard University, © President and Fellows of Harvard College, CC BY-NC-SA 4.0.

Figure 4. Sinoelmoa yangquanensis gen. et sp. nov., holotype, specimen YQZYW 15. A. Overview, drawing and photograph (dry-eth-eth composite; dashed line delimiting the area missing on side a) of right forewing. B. Detail of the course of CuA, drawing and photograph (eth-eth-dry composite), as located in A.

Figure 5. Wing venation of Permelmoa magnifica Prokop & Nel, 2011 (Parelmoidae Rohdendorf, 1962), holotype specimen Ld LAP 365, right forewing. A. Interpretative drawing under interpretation favoured herein (dotted line, twin imprints of vein sections; and see text), photograph (RTI extract), and normals visualization (RTI extract). B, C. Detail of the radial and median systems, as located in A, under the interpretation followed by Prokop and Nel (2011) (B) and the interpretation favoured herein (C).