Sigmaboilus fuscus, Gu, Junjie, Zhao, Yun-Yun & Ren, Dong, 2009

Gu, Junjie, Zhao, Yun-Yun & Ren, Dong, 2009, New fossil Prophalangopsidae (Orthoptera, Hagloidea) from the Middle Jurassic of Inner Mongolia, China, Zootaxa 2004, pp. 16-24 : 18-19

Sigmaboilus fuscus sp. nov.

( Figs. 1–2 )

Diagnosis: Forewing: Whole tegmen fuscous; precostal area approximately triangular; basal free part of CuA gently curved; second anterior branch of CuA+CuP1a pectinate with four branches; CuP1b slightly curved.

Hindwing: ScP and R with a long basal common stem; R diverging nearer wing base than in forewing, RP branched before first branch of RA; M bowed towards R and diverging before origin of RP.

Description: Forewings; long and narrow; base of tegmen constricted. Preserved length about 30.5 mm, width 8.7 mm (opposite the fusion of ScA with anterior margin, holotype). Area between ScA and anterior margin approximately triangular and numerous ‘radial veinlets’ coupled with regular cross-veins at its base, loose branches and network of irregular cross-veins take up distal part. ScA long, mildly undulate, reaching anterior wing margin slightly beyond first branch of RA. ScP apparently long, branches of ScP numerous and most of them end in stem ScA, straight and regular cross-veins between them; Area between ScP and R narrow. R straight and strong, R and M with basal common stem; R forking into RA and RP at about 1/3 basal tegminal length, RA posteriorly pectinate with 5 branches in preserved part, RP branched beyond first branch of RA, posteriorly pectinate at least with 4 branches; Area between R and M with straight and more or less parallel cross-veins in preserved part. M forked before the origin of RP, MA oriented towards RP at its origin, further gently curved and oriented toward posterior wing margin; Cross-veins at the base of area between CuA+M and CuP sigmoidal. Basal free part of CuA gently curved and slightly longer than basal free part of M; point of fusion of CuA and CuP1a beyond divergence of M; CuP1a twice the length of CuA before their fusion; CuA and CuP1a remaining united as CuA+CuP1a for a short and measurable distance, and exhibiting 6 terminal branches, first anterior branch of CuA+CuP1a oriented toward MP, beyond gently curved; second anterior branch of CuA+CuP1a pectinate with four branches; cross-veins between branches of CuA+CuP1a variable, some sigmoidal, some ramified; CuP1b slightly sigmoidal; CuP2 strong, sharply curved, probably Zshaped, cross-veins between CuP2 and CuP1b curved. 1A strong and similar to CuP 2 in shape, probably touching CuP2 at a point, 2A apparently S-shaped.

Hindwing: Poorly preserved and largely hidden by forewing; Preserved length about 27.8 mm. Area between ScA and ScP very narrow, ScP and R with basal common stem, basal free part of R slightly curved towards M; R diverging nearer wing base than in forewing, RA posteriorly pectinate with 5 branches in preserved part; RP branched before first branch of RA and pectinate at least with 6 branches, cross-veins between RA and RP regular, areas between branches of RP with straight cross-veins in basal part and reticulated cross-veins in distal part; M bowed toward R and diverging before origin of RP, MA and MP gently curved and subparallel; Cubital and anal areas missing.

Material: Holotype, male tegmen and poorly preserved hindwing, CNU-ORT-NN2008035; paratypes: 1, male tegmen: CNU-ORT-NN2008049.

Etymology: The specific epithet derives from Latin ‘ fuscus ’, for its fuscous wing.

Horizon and locality: Jiulongshan Formation, Middle Jurassic, Daohugou Village, Ningcheng County, Inner Mongolia, China.

Remarks: The new species can be distinguished from the type species in following features on the forewing: Precostal area approximately triangular; branching mode of CuA+CuP1a different; basal free part of CuA slightly curved; CuP1b between ‘handle’ and posterior wing margin curved; and CuP1a twice the length of CuA before their fusion. It differs from Sigmaboilus sinensis in having a whole fuscous tegmen, and second anterior branch of CuA+CuP1a pectinate.

Figures

FIGURE 1. Sigmaboilus fuscus sp. nov., photograph of holotype, CNU-ORT-NN 2008035.

FIGURE 2. Sigmaboilus fuscus sp. nov., line drawing of holotype, A. forewing; B. hindwing, CNU-ORT-NN 2008035.