Daniilacheta Gorochov & Coram, 2023

GOROCHOV, ANDREI V. & CORAM, ROBERT A., 2023, New and little known taxa of the order Orthoptera (Insecta) from the Upper Triassic and Lower Jurassic of England, Palaeoentomology 6 (2), pp. 198-204 : 199-200

Genus Daniilacheta Gorochov & Coram gen. nov.

Type species. Daniilacheta aristovi gen. et sp. nov., by present designation.

Composition. Only type species.

Etymology. After the first name of the Russian palaeoentomologist Daniil [=Danila] S. Aristov (in his memory) and the genus Acheta .

Diagnosis. Male tegmen ( Fig. 1A ) with a very long apical area and distinctly developed stridulatory apparatus having the following characters: lancet-like area also distinctly developed, probably moderately wide and with two or three crossveins in its distal half; distal parts of Sc and R+1MA1 strongly protruding beyond this area; harp area with strongly arcuate crossveins (“oblique veins”); diagonal vein and proximal part of CuA2 (before it) clearly developed; rest of CuA2 (behind diagonal vein) and majority of branches of MP+CuA1 almost straight to very slightly arcuate, obliquely longitudinal, with areas between them rather narrow and more or less equal in shape but gradually narrowing to tegminal apex; stridulatory vein obliquely transverse, rather long; chords strongly curved but not long.

Remarks. The new genus is similar to Bacharogryllus in the presence of two or more crossveins in the lancet-like area, but is distinguished from it by this area having more numerous crossveins in its distal half ( Bacharogryllus has one crossvein, whereas Daniilacheta gen. nov. has two or more) and by a shorter harp area with significantly more arcuate crossveins. The new genus differs from Archaegryllodes in having more numerous crossveins in the lancet-like area ( Archaegryllodes has only one crossvein) as well as having a shorter harp area and a longer stridulatory vein. Differences from Protogryllus are problematic with respect to the above discussion, but some specimens known from male tegmina and included in this genus by different authors are distinguished from Daniilacheta gen. nov. by the lancet-like area lacking crossveins, the harp area with almost straight crossveins, the apical area and distal parts of Sc and R+1MA1 distinctly shorter, and some of the MP+CuA1 branches clearly S-shaped.

It is necessary also to mention that Aenigmagryllus Gorochov, 1992 (Upper Jurassic or Lower Cretaceous of Mongolia), which has an unknown lancet-like area, is included in Protogryllidae without attribution to any subfamily and differs from the new genus in having less arcuate crossveins of the harp area, a strongly S-shaped portion of CuA2 located behind the diagonal vein, and a shorter costal (longest) chord. The two other subfamilies of Protogryllidae (Karataogryllinae Gorochov, 1985 and Falsispeculinae Gorochov, 1985) can be respectively distinguished from the new genus by a much longer costal chord of the male tegmen and by the absence of crossveins in the distal part of the lancet-like area mentioned above (Falsispeculinae and Protogryllinae differ from each other mainly in the structure of the base of this lancet-like area, unknown in the new genus, and in this connection, inclusion of this genus in Protogryllinae but not to Falsispeculinae is somewhat tentative).

Figures

FIGURE 1. Daniilacheta aristovi gen. et sp. nov., male tegmen, holotype LD/Orth 19, Dorset, Lower Jurassic. A, Reconstruction of spread venation. B, Photograph of imprint (part). C, Photograph of imprint (counterpart). Abbreviations: c – area with chords (distal parts of CuP, 1A and 2A); d – diagonal vein (oblique crossvein crossing CuA2 and having two branches near stridulatory vein); h – harp area with harp veins or “oblique veins” (crossveins between CuA1 and proximal part of CuP); lancet – lancet-like area between R and MA. Scale bar = 3 mm.