Menatgryllus longixiphus, Schubnel & Desutter-Grandcolas & Garrouste & Hervet & Nel, 2020

Schubnel, Thomas, Desutter-Grandcolas, Laure, Garrouste, Romain, Hervet, Sophie & Nel, André, 2020, Paleocene of Menat Formation, France, reveals an extraordinary diversity of orthopterans and the last known survivor of a Mesozoic Elcanidae, Acta Palaeontologica Polonica 65 (2), pp. 371-385 : 373-374

Menatgryllus longixiphus sp. nov.

Fig. 2 .

Zoobank LSID: urn:lsid:zoobank.org:act:DFC23D67-3E7E-4F55-854A-AEBC4F01B39C

Etymology: Named after its very long ovipositor.

Holotype: MNT-1053, female with legs and ovipositor well-preserved, abdomen and hind legs in ventral view, head and thorax in lateral position.

Type locality: New quarry, Menat, Puy-de-Dôme, France.

Type horizon: Middle Paleocene, Menat Basin.

Material.— Holotype only.

Diagnosis.—Acoustic tympanum present on fore tibia; forewings and hindwings both present in females; no serrulation on hind tibiae; tarsomeres 2 flattened; strong setae on the fastigium.

Measurements.—Fore femur 4.2 mm long; fore tibia 2.7 mm long; hind femur 8.0 mm long, 2.9 mm wide; hind tibia 7.5 mm long; ovipositor 17.5 mm long.

Description.—Body densely covered with short setae; head long and narrow in lateral view; scape longer than wide; left eye present but hardly visible, possibly protruding; fastigium distinct, but its shape unclear; with some strong setae (apical?); maxillary palpi hardly distinct; pronotum present in lateral position; lateral lobe probably longer than high, anterior angle longer than posterior one; legs all present; tarsi short with flattened second tarsomere ( Fig. 2 ); left fore leg with a well-developed outer tympanum, elongate and obliterate; right fore leg possibly with a smaller elongate inner tympanum; left tibia with three apical spurs; both legs with complete three-joint tarsi; basitarsomere I with two long and subequal apical spurs; mid legs complete, from coxae to tarsi; mid tibiae with four apical spurs (seen in ventral view: Fig. 2 ); hind femora thick and short, without a filiform apical part; hind tibiae slightly shorter than hind femora; with three inner apical spurs, the dorsal the longest and longer than half basitarsomere, also with three outer apical spurs, shorter than inner spurs, and with at least four inner and four outer subapical spurs, with no discrepancy between inner and outer subapical spurs; no serrulation between and above subapical spurs; hind basitarsomeres with several dorsal spines in addition to apical ones; forewings close to left hind femur; wings plicated, colored, except along veins; venation unclear; hind wings much longer than forewings and much longer than body; abdomen complete; subgenital plate small and transverse; distal margin concave; cerci broken, but right only long; ovipositor very long, more than twice hind tibia length; apex small; ornamentation not visible.

Remarks.—The shape of the hindlegs, with three-joint tarsi, the shape of the ovipositor and the presence of acoustic tympanum on tibia I attest that this fossil belongs to Grylloidea . The presence of three apical spurs on fore tibia could fit the synapomorphy of the family Gryllidae (sensu Chintauan-Marquier et al. 2016) , but the absence of serrulation on hind tibiae, the flattened shape of tarsomeres 2, and the presence of strong setae on the fastigium make an original combination of characters, supporting a new genus. Menatgryllus gen. nov. shares with the Baltic amber genus Eopentacentrus Gorochov, 2010 the presence of four pairs of subapical spurs on the hind tibiae but it differs from this genus in the fore tibia with three apical spurs instead of two ( Gorochov 2010). Some other fossil gryllid genera are described from the Paleocene or the Eocene, but they are based on isolated wings ( Gorochov 1992; Rust 1999), impossible to compare to Menatgryllus gen. nov.

Stratigraphic and geographic range.— Type locality and horizon.

Figures

Fig. 2. Grylloidean orthopteran Menatgryllus longixiphus gen. et sp. nov., holotype, MNT-1053 from Paleocene of Menat, France. Photograph of habitus A1), reconstruction of hind tibiae and tarsus (A2, left; A3, right).