Gerarus bruesi Meunier, 1909

Béthoux, Olivier & Nel, André, 2002, Venation pattern and revision of Orthoptera sensu nov. and sister groups. Phylogeny of Palaeozoic and Mesozoic Orthoptera sensu nov., Zootaxa 96, pp. 1-88 : 35-37

Gerarus bruesi Meunier, 1909

( Figs 13­14 )

1909 Archaeacridites bruesi Meunier, 45­46, fig. 2 (original description) 1919 Sthenaropoda bruesi ­ Handlirsch, 547, fig. 48.

1929 Archaeacridites bruesi ñ Vignon, 112, pl. 3, fig. 2.

1983 Gerarus bruesi ­ Burnham, 35­36, figs 18­19.

1992 Gerarus bruesi ­ Kukalová­Peck & Brauckmann, 2461, fig. 27. 1992 Gerarus bruesi ­ Carpenter 122, fig. 72.3a.

Material: holotype specimen MNHN­LP­R.51164, Laboratoire de Paléontologie, Muséum National d’Histoire Naturelle, Paris, France.

Geological settings: Stephanian, Upper Carboniferous, Commentry, Allier, France.

Diagnosis. CuPb lost in network below CuPa/CuPa. MA2 simple or very distally ramified; origin of MP in very distal position, just distal of first ramification of CuA + CuPa; CuPb very ramified.

Note. The revision of this specimen was necessary because Burnham (1983: fig. 18) did not figure vein ScA and because the convexity of main veins was unknown, partly indicated in Kukalová­Peck & Brauckmann (1992), but with some differences with the present re­description. These last authors figured several veins at the wing base, which they named ‘MA’, ‘CuA’ and ‘AA1’. These veins are not visible on the fossil, particularly because there is a common basal stem of R + M + CuA.

and photograph (light­mirrored). (scale bar represents 5 mm).

Re­description. Counterpart of a nearly complete forewing perfectly preserved with only the apex missing. Preserved length 46.0 mm, width 15.1 mm; ScA reaching anterior margin 12.3 mm from wing base; ScP anteriorly pectinate, with branches simple and slightly sigmoidal; base of RP 18.5 mm distal of wing base; ScP and R (+ M + CuA) basally separated; presence of a common stem R + (M + CuA); RA convex, anteriorly pectinate, with its branches dichotomously ramified; first branch of RA 8.7 mm distal of base of RP; area between RA and RP with sigmoidal cross­veins; convexity of RP neutral; RP dichotomously ramified distally, with one anterior branch fused with posterior branch of RA; CuA separated from M in the basal third of the wing; M dichotomously ramified into MA and MP; first anterior branch of MA close to RP, dichotomously ramified; area between branches of RP and branches of M with more or less regularly spaced straight cross­veins; free part of CuA short, basal of its fusion with CuPa; CuA + CuPa posteriorly pectinate, with its two first posterior branches concave; sigmoidal cross­veins between M and CuA + CuPa; CuPa short basal of its fusion with CuA; CuPa with an apical fork; a network of irregular cells in area between CuA + CuPa and CuPa; division of CuP into CuPa and CuPb near wing base; an anterior branch of CuPb (CuPb), lost in the network between CuPb and CuPa, posterior branch of CuP (CuPb) divided into three long branches; area between CuPa/CuPa and CuPb very broad (largest width opposite origin of CuPa /CuPa), with an irregular network of cells; 1A apparently separated from CuP close to the base of the wing, distally ramified; three main veins in anal area basal of 1A, only the third being branched.

Comparison with other Geraridae . Gerarus bruesi is very similar to Gerarus danielsi . These two taxa share: (1) a simple MA2 or very distally ramified; (2) an anterior branch of MP simple or very distally ramified; (3) a network of cells in area between CuPa/CuPa; (4) a densely ramified CuPb. Gerarus vetus , as figured by Kukalová­Peck & Brauckmann (1992: fig. 13), has different right and left forewings, with apparently different organisation of veins MA, MA1, MA2 and MP. Nevertheless, the right forewing has an anterior branch of MA very close to RP and these veins being connected by a short crossvein. This character is also present in Gerarus bruesi .

Figures

FIGURE 13. Gerarus bruesi, holotype specimen MNHN­LP­R. 51164 (counterpart): reconstruction

FIGURE 14. Gerarus bruesi, holotype specimen MNHN­LP­R. 51164 (counterpart): photograph of the medio­cubital area (detail of common stem M + CuA, distal free part of CuA, and fusion of CuA and CuPa). (scale bar represents 3 mm).