Permoridium fresenaci sp. nov. (Figures 2–3)
urn:lsid:zoobank.org:act:B064BCBF-35B3-4AF6-9B68-
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Ditch along the road south of Freisen-Grügelborn/Saarland. Lower Permian, Glan Subgroup, highest Meisenheim Formation (M 10), top of Odernheim Subformation; Asselian or early Sakmarian.
After ‘Fresenacum’, Latin designation for the village of Freisen in the Saarland. The type locality Grügelborn is a district of Freisen.
As for genus, by monotypy.
The basal half (at least) of a forewing except for clavus, preserved part 23.0 mm long, 11.2 mm wide; the relative convexities of the main longitudinal veins quite similar; wing tegminized with a net of large cells, each subdivided into a net of small irregular cells forming a reticular pattern; costal margin strongly curved basally and straight distally; vein ScA slightly distant from costal margin at wing base but rapidly approximating it to be closely parallel to it up to most distal preserved part of wing, ScA emitting one short anterior branch at its extreme base, ending into C, and two posterior branches which are vanishing in area between it and ScP; at wing base, basal parts of ScA and ScP strongly approximating and probably basally with a common stem, even if not preserved; ScP approximating R near wing base, and strongly diverging from it more distally, to approximate it again near its apex, ScP ending into RA; area between ScA and ScP quite broad, 1.8 mm wide, with two or three rows of large cells in-between; area between ScP and R broad, 1.4 mm wide, with one row of large cells; R hardly wavy, separating into RA and RP far from wing base, 18.0 mm away; only basal parts of RA and RP preserved, with two rows of large cells inbetween; vein M+CuA very shortly appressed to R, diverging from it 0.4 mm from extreme wing base, strongly diverging from R and strongly wavy distally; area between R and M strongly broadened in its distal part, with two or three rows of large cells in-between; M emitting an oblique MP 8.2 mm from wing base, ending into CuA 1; area between M and CuA with secondary oblique veins defining a net of large cells; CuA separating from M 4.0 mm from wing base, basal part of CuA before its fusion with crossvein cuacup weak and short; cua-cup very strong, 2.6 mm long, and aligned with distal part of CuA and basal part of CuP; CuA divided into two strong branches 4.8 mm from point of fusion of its basal part with cua-cup; CuA 1 (anterior branch) simple, CuA 2 (posterior branch) emitting short posterior branches; CuP strong at base, very weak distal of separation from cua-cup at 1.4 mm from wing base, straight and closely parallel to CuA and PCu; PCu as weak as CuP, shortly fused with it (0.4 mm), at 2.2 mm of wing base and separating again distally to be straight; anal area (clavus) not preserved.
The general shape of the wing and the straight and closely parallel veins CuP and PCu indicate that this fossil is a forewing. The main veins having the same convexity plus the presence of a net of large cells that are subdivided into a dense net of small cells indicate that it is tegminized. The presence of a vein ScA closely appressed to the costal margin, the broad area between ScA and ScP, the ScP approximating R and distally diverging from it, the presence of a M+CuA with a common base with R and the general shape of the wing support an attribution to the Hemiptera. The crossvein cua-cup is generally weaker than CuA in the Acercaria. The strong cua-cup aligned with the distal part of CuA and the basal part of CuP plus the weakened basal part of CuA in Permoridium fresenaci gen. et sp. nov. are unusual but can be found also in some extant Hemiptera, e.g., in Cicadellidae (Nel et al. 2012). The presence of two main branches of CuA is a general character of the Acercaria, lost in the Thripida and few other clades, by reduction of the size of the forewing. Nevertheless, P. fresenaci gen. et sp. nov. displays some characters unique for Hemiptera, viz. the base of M+CuA situated at the extreme wing base; CuA, CuP and PCu very closely parallel; ScA emitting two posterior branches.
In the Sternorrhyncha (including the extinct Paleorrhyncha) and the Auchenorrhyncha, the vein M+CuA separates from R distinctly distal from wing base. Some Auchenorrhyncha (e.g., some extant Cicadellidae and the Triassic Granulidae, Saaloscytinidae, and Maguviopseidae) have a net of large cells that are subdivided into a dense net of small cells in their tegmina (Martins-Neto et al. 2006; Shcherbakov 2011; Fu et al. 2022, Fu and Huang 2022), but their M+CuA separates from R in a distinctly distal position, they have no ScA with posterior branches. In the Heteroptera, the situation is more confusing because of the tegminisation occurring in many taxa. Nevertheless, in the most ‘basal’ clades (Enicocephalomorpha, Dipsocoromorpha, Nepomorpha, Gerromorpha) of true bugs, the vein M+CuA clearly separates from R far from wing base (e.g., see figures in Schuh and Weirauch 2020: figs 44.1B, 45.1B, 47.1C, 50.1C). The structure of a M+CuA distally emerging from a common stem with R and a cuacup, characteristic of the Acercaria (Nel et al. 2012), is clearly visible in the oldest known Nepomorpha (see Criscione and Grimaldi 2017: fig. 4.4). Even it is still present in the Hypsipterygidae in which the basal stem of R +M+CuA is very short (Rédei 2007: fig. 9). In the more ‘derived’ clades, the situation is less clear because of the strong modifications occurring in the tegmens. Nevertheless, the vein M is currently interpreted as emerging in a distal position from R (e.g., see Schuh and Weirauch 2020: fig. 63.1C). Furthermore, no Heteroptera has a well-developed vein ScA.
In the extant Coleorrhyncha (Peloridiidae), the situation is again somewhat confusing because of the tegminisation of the forewing, resulting in the branching of M+CuA from R and in RP looking like crossveins. While in P. fresenaci gen. et sp. nov., the wing base bears eight veins, viz. C, ScA, ScP, R, M+CuA, CuP, PCu and A which is not preserved, in the extant Coleorrhyncha and other Hemiptera, only seven veins are developed: C, ScA, ScP, R+M+CuA, CuP, PCu and A (Figure 4). P. fresenaci gen. et sp. nov. shares with the Peloridiidae a strong ScA, distant from costal vein and with a short anterior branch at its extreme base, ending into C, plus posterior branches, unlike all the other Hemiptera. Also, the extant Coleorrhyncha have a particular shape of ScP that is appressed and below R +M+CuA at extreme wing base (Burckhardt 2009: figs. 5– 7), a situation that resembles that in the new fossil in which ScP is appressed to R. The extant Coleorrhyncha also share with the new fossil a very long and well-defined ScP, ending into RA. These three characters are interpreted as putative synapomorphies of the new fossil with this clade. A further synapomorphy could be the ScA ending into ScP. The tegminisation of the forewing with large cells could be a further one but tegminisation also occurs in some Auchenorrhyncha and Heteroptera. P. fresenaci gen. et sp. nov. differs from extant Peloridiidae in the much larger tegmen size>23 mm versus 2–5 mm. The other fossils currently attributed to the Coleorrhyncha also have smaller tegmina (Popov and Shcherbakov 1991).
The extinct families of Coleorrhyncha (Hoploridiidae, Karabasiidae and Progonocimicidae) have no ScA well separated from C and with branches and an elongate and well-defined ScP (Popov and Shcherbakov 1991). The Progonocimicidae have a ScP ‘incorporated’ into R, while the Karabasiidae and Hoploridiidae have an ‘obscure’ and short ScP (Popov and Shcherbakov 1991; Wang et al. 2009; Szwedo 2011). Popov and Shcherbakov (1996), and Shcherbakov and Popov (2002, pp. 147–148) proposed the following synapomorphies to unite the fossil and extant Coleorrhyncha: ‘suprantennal ledge continuous below median ocellus; forewings overlapping in repose (left one uppermost); forewing with enlarged posterior apical cells, short transverse CuA2 and broad appendix; coupling fold very short in forewing; fore and middle tarsi two-segmented [a character frequent in Acercaria]; pygophore barrel-shaped, parameres protruding and elbowed’. These body characters are quite difficult to observe or are not available in the fossil taxa. Nevertheless, Gakasha calcaridentata Jiang, Wang and Szwedo 2019, a unique Progonocimicidae found in Burmese amber, shows a suprantennal ledge continuous below median ocellus, and fore and middle tarsi two-segmented (Jiang et al. 2019). The wing venation characters are present in representatives of other clades of Hemiptera. Thus, it seems that the attributions to this suborder of the fossil genera and species based on isolated wings are rather poorly grounded.
Ye et al. (2019, p. 138) considered the Progonocimicidae as belonging to the clade (Coleorrhyncha + Heteroptera) and not strictly to the Coleorrhyncha. They also indicated that ‘ Evans (1981) and Popov and Shcherbakov (1996) discussed the phylogeny of peloridiids, but their hypotheses are not testable for methodological reasons’.
It is interesting to note that the Hoploridiidae shares with P. fresenaci gen. et sp. nov. the presence of large cells subdivided into numerous smaller cells.