Paleochina minuta, 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 : 378-381

Paleochina minuta sp. nov.

Fig. 7B, C .

Zoobank LSID: urn:lsid:zoobank.org:act:C33D57DF-9413-4C75-A312-906D99EC2532

Etymology: Named after the minute size of the tegmen.

Type material: Holotype: MNT NEL 1928 . Paratype: MNT BDL 1043 , both isolated tegmina .

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

Type horizon: Middle Paleocene, Menat Basin.

Material.— Holotype and paratype only.

Diagnosis.—M+CuA separating from R well basal of apex of ScA; one row of cells between CuA+CuPaα and CuPaβ.

Description.— Holotype MNT NEL 1928 ( Fig. 7B ). Forewing hyaline, very narrow, 14.0 mm long, 2.2 mm wide in widest part; posterior margin straight; C very weakly curved basal of apex of ScA; area between C and ScA narrow, 0.3 mm wide, but poorly preserved; apex of ScA 4.3 mm from wing base; area between ScA and ScP 0.2 mm wide; area between C and ScP narrow, 0.2 mm wide, with a series of short parallel crossveins; ScP and R strongly approximate but not touching; apex of ScP 2.5 mm distal of that of ScA; area between C and RA darkened, 0.2 mm wide, without visible crossvein, except near apex of RA; apex of RA 1.5 mm from wing apex; M+CuA appressed to R in basal half of wing, separating from R 4.0 mm from wing base; independent stem of M+CuA 1.2 mm long; M simple; CuPaα weak, ending into CuA 0.4 mm from point of separation between M and CuA; CuA+CuPaα simple; one row of cells between M and CuA+CuPaα; base of RP 7.3 mm distal of wing base; area between RA and RP narrow, 0.4 mm wide, with one row of simple crossveins between them; RP with five posterior branches, with two rows of cells between them; one row of cells between CuA+CuPaα and CuPaβ; one row of cells between M+CuA and CuPa, and between CuPa and CuPb; CuPb straight, area between CuPb and anal vein very narrow.

Paratype MNT BDL 1043 ( Fig. 7C ). Same pattern of coloration and venation as for holotype, tegmen ca. 14.5 mm long, 2.8 mm wide .

Remarks.— Paleochina duvergeri sp. nov. and Paleochina minuta sp. nov. have very similar tegmina, that of P. duvergeri being longer than that of P. minuta and with few differences indicated in the respective diagnoses. We consider that they belong to different species within the same genus. Sexual dimorphism that concern the size and shape of the tegmina can occur in the Caelifera. As we do not know the sex of these insects, it is not totally excluded that they could correspond to male and female of the same species but differences in the venation support a specific non-identity. These tegmina are typical of the Eumastacoidea , viz. reduction of vein CuPaα ( Sharov 1968; Dirsh 1975), tegmen very narrow, with few intercalary cells between main veins and a narrow area between radial vein and costa. Such structures can be found in some Chorotypidae Stål, 1873 and Eumastacidae Burr, 1899 ( Dirsh 1975; internet site www.orthopteran.speciesfile.org). Among the Chorotypidae , Paleochina gen. nov. differs from Erucius Stål, 1875 (Eruciinae Burr, 1899) in the broader radial area and broader and darkened area between RA and C ( Dirsh 1975: fig. 2). This last character of Paleochina gen. nov. is present in the genus China Burr, 1899 , but China mantispoides (Walker, 1870) , unique species of this genus, has only three branches of RP instead of five in Paleochina gen. nov. ( Descamps 1974: fig. 30). Eupatrides Brunner von Wattenwyl, 1898 , second genus of the subfamily Chininae Burr, 1899 , has a broader area between C and ScA, with C making a strong curve instead of being straight. Among the winged Chorotypinae Stål, 1873, Burrinia Bolívar, 1930 has two rows of cells in area between ScA and C and less developed area of RP ( Bolívar 1930). Chorotypus Bolívar, 1930 , Orchetypus Brunner von Wattenwyl, 1898 , Phyllochoreia Westwood, 1839 , and Hemierianthus Saussure, 1903 have broader tegmina, with numerous rows of cells between main veins. Pseudorchetypus Descamps, 1974 and Scirtotypus Brunner von Wattenwyl, 1898 has C making a strong curve instead of being straight in its basal part ( Descamps 1974). The extant Erianthinae Karsch, 1889 have a broader area between C and ScP.

Among the extant winged Eumastacidae , several genera, e.g., Eumastax Burr, 1899 , Homeomastax Descamps, 1979 , Hysteromastax Descamps, 1979 , Helicomastax Rowell and Bentos-Pereira, 2001 , Paramastax Burr, 1899 , and Temnomastax Rehn and Rehn, 1942 , among others, have much reduced venation of the tegmina, with three or less branches of RP ( Dirsh 1975; Descamps 1974, 1979; internet site www. orthopteran.speciesfile.org). Paleochina gen. nov. is probably not a Eumastacidae and more likely a Chorotypidae , but a more complete specimen with genitalia at least partly preserved will be necessary to better support its exact relationships.

Among the fossil Eumastacoidea , Promastax archaicus Handlirsch, 1910 (type species of the fossil family Promastacidae Kevan and Wighton, 1981 , Paleocene–Eocene, Canada, the distal two-third of a tegmen) has only three branches of RP, ScA ending on costa distal of base of RP, a broad area between RA and RP, unlike Paleochina gen. nov. ( Handlirsch 1910: fig. 1). Notice that this fossil family is based on few, poor characters ( Kevan and Wighton 1981), and should be revised. The second genus and species of this family, Promastacoides albertae Kevan and Wighton, 1981 (same outcrop) is based on a nearly complete tegmen. The original description and figure are problematic, but it seems to have M with three branches, and a quite broad wing, unlike the Eumastacoidea . Its phylogenetic relationships are uncertain.

All the described fossil taxa currently placed in Eumastacidae are based on wings, thus their exact positions in the Eumastacoidea are tentative. The Jurassic genus Archaeomastax Sharov, 1968 differs from Paleochina gen. nov. in the broader area between ScP and RA ( Sharov 1968). The Eocene Eoerianthus Gorochov in Gorochov and Labandeira, 2012, has only three branches of RP and apices of ScP and RA very close to wing apex (in the type species E. eocaenicus Gorochov, 2012 ). The second species E.? multispinosa ( Scudder, 1890) , originally placed in the fossil genus Tyrbula Scudder, 1885 (type species Tyrbula russelli Scudder, 1885 ), and Truxalidae, is rather poorly preserved. The Paleocene–Eocene Eozaenhuepfer Zessin, 2017 has a two-branched median vein ( Zessin 2017b), while it is simple in Paleochina gen. nov. The fossil genus Taphacris Scudder, 1890 is rather poorly defined ( Zeuner 1944; Rehn 1948). Its type species Taphacris reliquata Scudder 1890 (Eocene–Oligocene of Florissant, USA) has a simple M but only four branches of RP, unlike Paleochina gen. nov. ( Scudder, 1890). Taphacris bitttaciformis Cockerell, 1909 (same outcrop) is poorly described and figured, nevertheless it has a three-branched RP ( Cockerell 1909, 1926), unlike Paleochina gen. nov. Taphacris bitttaciformis tillyardi Cockerell, 1926 (same outcrop) is even based on a more fragmentary fossil. The Chinese Paleocene Taphacris stenosis Lin, 1977 has also four branches of RP and a simple M, but a distinctly longer ScA than in Paleochina gen. nov., reaching mid wing level ( Lin 1977). The Chinese Early Cretaceous Taphacris turgis Lin, 1980 has apparently the same characters but it would need a revision ( Lin 1980). The Miocene Paleomastacris ambarinus Pérez-Gelabert, Hierro, Dominici, and Otte, 1997 (from the Dominican amber) is based on an apterous fossil, not comparable to Paleochina gen. nov. ( Pérez-Gelabert et al. 1997; Pérez-Gelabert 2002). Lastly Lewis et al. (1990) cited a Eumastacidae from the Miocene of Idaho. Orthacanthacris rhenana Theobald, 1937 (Oligocene, Germany) could also be an Eumastacoidea for the narrow tegmina and thin and long hind legs; it differs from Paleochina gen. nov. in the more numerous branches of RP ( Théobald 1937). This taxon needs to be revised. Lewis (1974) figured undescribed specimens from the Oligocene of Ruby River Basin (Montana) that are attributable to the Eumastacoidea . Lewis (1976) also figured an undescribed eumastacoid tegmen (either in Eumastacidae or Chlorotypidae) from the same outcrop. Its area between C and ScA is broader than in Paleochina gen. nov. Martins-Neto (1991a) cited the presence of an Eumastacoidea in the Cretaceous of the Crato Formation in Brazil, that was never described.

Among the other Caelifera described from Menat, only “ Oedipoda spec. ” and Ochrilidia lineata are comparable to Paleochina gen. nov. “ Oedipoda spec. ” differs from Paleochina gen. nov. in the presence of three dark spots on the tegmen. Ochrilidia lineata differs from Paleochina gen. nov. is the absence of secondary zigzagged longitudinal veins between branches of RP. It also differs from Paleochina duvergeri in the distinctly shorter tegmina (ca. 16–17 mm long). The “genus and species A” described above differs from Paleochina gen. nov. in the very broad costal area in forewing. Heads (2008) described an apterous Eumastacoidea Proscopiidae from the Lower Cretaceous of the Crato formation in Brazil, showing the antiquity of this superfamily.

Stratigraphic and geographic range.— Paleocene, Menat Formation, Menat, France.

Elcanoidea Handlirsch, 1906

Elcanidae Handlirsch, 1906

Remarks.—The exact phylogenetic relationships of the Elcanoidea within the Orthoptera remain debatable. If Gorochov and Rasnitsyn (2002) considered them as sister group to all other Orthoptera, Béthoux and Nel (2002) considered them as Caelifera on the basis of a phylogenetic analysis.

Figures

Fig. 7. Tegmina of chorotypid orthopteran Paleochina spp. from Paleocene of Menat, France. A. Paleochina duvergeri gen. et sp. nov., holotype, MNT NEL 3267; A1, left wing; A2, right wing (reversed view). B. Paleochina minuta sp. nov., holotype, MNT NEL 1928. C. Paleochina minuta sp. nov., paratype, MNT BDL 1043. Scale bars 5 mm.Abbreviations: C, costa; CuA/P, cubitus anterior/posterior; CuPaα, most anterior branch of CuP; CuPaβ, median branch of CuP; CuPb, posterior branch of CuP; M, median vein; RA/P, radius anterior/posterior; ScA/P, subcostal anterior/posterior.