Parelmoidae Rohdendorf, 1962

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

Family Parelmoidae Rohdendorf, 1962

Type genus.

Parelmoa Carpenter, 1947 .

Included genera.

Diapha Kukalová-Peck, 1974 ; Elmodiapha Kukalová-Peck, 1974 ; Paradiapha Kukalová-Peck, 1974 ; Permelmoa Prokop & Nel, 2011 ; Permodiapha Kukalová-Peck, 1974 ; Permuralia Sinichenkova & Kukalová-Peck, 1997 ; Protodiapha Kukalová-Peck, 1974 ; Pseudelmoa Carpenter, 1947 ; Stenodiapha Kukalová-Peck, 1974 ; Sinoelmoa gen. nov.

Commented diagnosis.

ScP long, ending beyond the first fork of RP (plesiomorphy within Diaphanopterodea ); near wing base, shortly after its origin, CuA fused for some distance with, or running closely along, R + M (apomorphy; as currently documented, shared with all Diaphanopterodea except Sinodiaphidae , in which CuA is connected with M by a short cross-vein, and Diaphanopteridae , in which the connection of CuA and M is very brief); first cross-vein in the CuA – CuP area very short and oblique, with CuA displaying a clear inflexion at the point of connection with this cross-vein [also present in Diaphanopteridae , Carrizodiaphanoptera and, to some extent, Elmoidae (Fig. 3 ); possibly an apomorphy of the entire Diaphanopterodea – except for Sinodiaphidae , in which this state is primarily absent –, and with presumed secondary losses in various families, such as Martynoviidae ]; MP branched (plesiomorphy within Diaphanopterodea ); CuP with 1–3 distal branches (plesiomorphy within Diaphanopterodea ); developed anal area (putative apomorphy for the family).

Remarks.

The combination of (i) an overall rich venation, (ii) a long fusion of CuA with R + M (or, CuA running very close to R + M for some distance), and (iii) a cua-cup cross-vein very short, is generally used to identify members of the Parelmoidae . The Pennsylvanian Diaphanopteridae differ from this family only by lacking character state (ii) (see Béthoux and Nel 2003). Given the polarity of several character states listed as diagnostic of the family, it is not excluded that this taxonomic concept might represent a paraphyletic entity, to include other Diaphanopterodea families, such as Elmoidae .

Carpenter (1992) considered the six genera and 10 species reported from the Obora locality (Permian, Cisuralian, Sakmarian), and originally assigned to the Elmoidae or Parelmoidae ( Kukalová-Peck 1974) , as of uncertain Parelmoidael affinities. Addressing aspects of species delimitation, and the systematics of these species, is made difficult by post-depositional deformations this material endured. Nevertheless, wing venation character states they display tend to indicate a placement to the family Parelmoidae as delimited above, in particular the well-developed anal area. Also, despite deformation, this comparatively large sample allows appreciating variation in character states variability (in other words, how the extent of variability varies within families), likely to differ among (and within) the closely related families Diaphanopteridae , Parelmoidae and Elmoidae (see below and Kukalová-Peck and Sinichenkova 1992).

Notably, a distal fork of CuP is common in the Obora material, with some specimens displaying an early fork, and even a 3 - branched CuP. The relation between RP and MA is also very variable across the corresponding species, ranging from a complete lack of fusion to a long one. In contrast, species of the genus Parelmoa Carpenter, 1947 (Fig. 2 A – D ) show more stable venational features (CuP simple; MA and RP connected by a short cross-vein). Among other Parelmoidae , the monotypic genera Pseudelmoa Carpenter 1947 (Fig. 2 E ) and Permuralia Sinichenkova & Kukalová-Peck, 1997 (Fig. 2 F ) remain similar to Parelmoa spp. in most of their venational features. Also, Elmoa trisecta Tillyard, 1937 ( Elmoidae ; Fig. 3 ) shows rather stable venational features, with a consistent occurrence of a (i) distally forked CuP and (ii) a MA distinct from RP, with a cross-vein connecting the two veins shortly after the origin of the latter. The Obora material is therefore unusual in several respects. Instead of attempting to finely resolve relationships between the corresponding taxa, whose variability in many aspects cannot be properly appreciated, we believe it is more sensible to use the Parelmoidae as a broad taxonomic concept, possibly paraphyletic (i. e., a grade), to include the Obora 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.