PROTOGRYLLIDAE, AND

Josse, Hugo, Faberon, Léo, Schubnel, Thomas, Nel, André & Desutter-Grandcolas, Laure, 2023, Reconciliation between neontology and paleontology in the Gryllidea (Orthoptera, Ensifera): reinterpreting the venation of the stridulatory apparatus in crickets, Zoosystema 45 (24), pp. 769-801 : 778

FOREWING VENATION PATTERN IN FOSSIL † PROTOGRYLLIDAE AND † BAISSOGRYLLIDAE

As currently defined, the † Protogryllidae and † Baissogryllidae show a similar and relatively stable venation patterns ( Pérez de la Fuente et al. 2012; Wang et al. 2019). The general organisation of their forewings is almost similar to that of modern crickets, with a lateral field and a dorsal field, a median fold, and a fan between R and CuA (possibly corresponding to a flexible zone, as in mole crickets).

Lateral field. In these fossils, the location of the putative C is often not preserved. The most anterior visible vein is Sc, which has the same pectinate branching as in modern Grylloidea ( Fig. 6 ). Posteriorly, R is present and strongly convex. Then, the M is fused basally with CuA. A lanceolate cell ( Fig. 6 ) is present between R and M: it is basally closed by a short transverse vein (r-m) located at the level of the divergence of M with CuA, and distally closed by a curved RP that partially merges with MA (as in modern Grylloidea , see above). Contrary to the latter, some † Protogryllidae have several secondary transverse veins in the lanceolate cell, as for example † Angarogryllus angaricus ( Sharov, 1968) ( Fig. 6A ). In others, like † Falsispeculum karatavicum ( Sharov, 1968) ( Fig. 6B ), veins between R and M+CuA at the base of the lanceolate cell are very similar and none is stronger than the others, complicating the identification of r-m among the crossveins. This crossvein r-m can either have an oblique direction towards wing base (obliquely inverted) between R and M ( Fig. 6A, B, D ), or be rather transverse ( Fig. 6E, C ). Some † Baissogryllidae (e.g., † Anglogryllus lyristes Gorochov, Jarzembowski & Coram, 2006 , Fig. 6E ) have a short r-m making a ‘constriction’ of the base of the lanceolate cell ( Fig. 6E ), a situation similar to that of the modern Grylloidea ( Figs 3 ; 4 ; 5A ).

R divides distally into a convex anterior branch RA and a rather concave posterior branch RP, well visible in † Angarogryllus angaricus ( Appendix 3: Fig. S5A ). RP is strongly curved basally and partially fuses with MA. The latter, also well visible in † Angarogryllus angaricus , is clearly convex. The fan is often very poorly preserved in fossils, especially for the MP branch. However, applying a conservative approach, we consider that M divides into two branches MA and MP (notably slightly visible in the unidentified † Baissogryllidae no. CCNH-293, Fig. 6D ). These two branches are relatively thin and present in the fan (a situation similar in the modern Grylloidea ).

Dorsal field. The clearly convex CuA diverges from M and joins CuPa crossing the median fold (well visible in † Angarogryllus angaricus , Appendix 3: Fig. S5A ). In the † Protogryllidae and some † Baissogryllidae , the CuA is longer and oblique ( Fig. 6A, B, C ), whereas in other † Baissogryllidae , it is transverse between the two fields ( Fig. 6D,E ). CuA merges with CuPaα, after its bifurcation with CuPaβ and before the bifurcation between CuPaα1 and CuPaα2. Between CuPaα and CuPaβ, there is a strong crossvein, which corresponds to d1 ( Fig. 6 ). Another strong crossvein d2, in alignment with d1, is present between CuPaβ and the anal node at the level of the plectrum. The harp is thus located between CuPa, CuPaβ, d2 and PCuA. In observed † Protogryllidae and † Baissogryllidae (see Appendix 3: Figs S5 ; S 6 ), we noticed a reduced vein in the harp that could correspond to the CuPb, because of its base connected to that of CuPa. These fossils have two branches of PCu, PCuA and PCuP, with their characteristic strong and curved base ( Fig. 6 ). While it has been suggested that the † Baissogryllidae and † Protogryllidae may have a file as in modern crickets (i.e., on the highly curved PCu), no stridulatory teeth are visible on photographs or illustrations of fossil specimens that we have studied. Some teeth are however visible on the PCuA in some undescribed baissogryllids from the lower Jurassic of Luxembourg (H. J. and A. N., pers. obs.), supporting this hypothesis, but it cannot be generalized to all baissogryllid and protogryllid fossils. Two anal veins, AA and AP, are located posteriorly. In the † Baissogryllidae that we observed ( Fig. 6C, D, E ) but not in the † Protogryllidae ( Fig. 6A, B ), the area between the CuPaα2 and CuPaβ is widened: by its position, this area could correspond to the mirror cell s. str. (mi) of modern crickets, but it is distally opened and not closed by s1 as it is in modern crickets.

Figures

FIG. 6. — Hypothesis of primary venation homology of male forewing of †Protogryllidae (A, B) and †Baissogryllidae (C-E): A, †Angarogryllus angaricus (Sharov 1968), PIN 1873-16; B, †Falsipseculum karatavicum (Sharov 1968), PIN 3791/1345; C, †Neosharategia paradoxa Gorochov, 1992, PIN 4270-210a; D, †Baissogryllidae sp., CCNH-293;E, †Anglogryllus lyristes Gorochov et al., 2006,MNEMG 2003.46. Abbreviations:“ha”, distally opened harp; “mi”, distally opened mirror, others and colour code, see text. Grey dash lines represent folds. Scale bars: 1 mm.

FIG. 3. — Hypothesis of primary homology of venation of male Grylloidea:A, Natula longipennis (Serville, 1838) (MNHN-EO-ENSIF9933, Trigonidiidae);B, Lerneca fuscipennis (Saussure, 1874) (MNHN-EO-ENSIF9780, Phalangopsidae). Abbreviations and colour code: see text. Scale bars:1 mm.

FIG. 4. — Hypothesis of primary homology of venation of male Grylloidea: A, Brachytrupes membranaceus (Drury, 1773) (MNHN-EO-ENSIF9769, Gryllidae); B, Phyllogryllus sp. (MNHN-EO-ENSIF9768, Oecanthidae). Abbreviations and colour code: see text. Grey dash lines represent folds. Scale bars: 5 mm.

FIG. 5. — Hypothesis of primary venation homology in male Grylloidea with particular forewing venation:A, B, species with ‘shortened’ wings; B, C, species with ‘reduced’ stridulatory apparatus.A, Landreva sp. (MNHN-EO-ENSIF9775, Gryllidae); B, Nemobius sylvestris (Bosc, 1792) (MNHN-EO-ENSIF9786, Trigonidiidae); C, Tafalisca lineatipes Bruner,1916 (MNHN-EO-ENSIF9760, Oecanthidae);D, Aphonomorphus sp.(MNHN-EO-ENSIF9764, Oecanthidae).Abbreviations:‘ha’, distally opened harp; ‘mi’ distally opened mirror; others and colour code: see text. Grey dash lines represent folds. Scale bars: 1 mm.