Locustopsis rhytofemoralis, Gu, Jun-Jie, Yue, Yanli, Shi, Fuming, Tian, He & Ren, Dong, 2016

Gu, Jun-Jie, Yue, Yanli, Shi, Fuming, Tian, He & Ren, Dong, 2016, First Jurassic grasshopper (Insecta, Caelifera) from China, Zootaxa 4169 (2), pp. 377-380 : 377-379

Locustopsis rhytofemoralis sp. nov.

Holotype: CNU-ORT-NN2011010PC Diagnosis: ScA long, reaching anterior margin close to mid-length of wing, distal of the divergence of M; MA forked into MA1 and MA2 basally, at the level of the origin of CuPab; hind lobe of pronotum long. Etymology. The specific epithet derives from Latin “ rhyto ”, for its vein of femora.

Occurence. Jiulongshan Formation, Middle Jurassic (Bathonian–Callovian boundary interval), Daohugou Village , Shantou Township, Ningcheng County, Inner Mongolia, China.

Description. Male ( Fig 1 ): small size, body 15.0 mm long, measured from the head to the abdominal apex; Head ( Fig 2 A): 3.4 mm high, hypognathous; antennal sockets strongly rimmed; scape slightly longer than pedicle, both of them distinct wider than flagella; compound eyes rather big, 1.2 mm long, oval; mandible stout, clypeus large, maxillary and labial partially preserved; subocular furrow S-shaped; genae short. Thorax ( Fig 1 ): pronotum saddle-shaped, 3.8 mm long, with large hind lobe of disc; this lobe extending posteriorly and covering the basal part of the tegmina, apex looks round; lateral lobe well developed, 2.7 mm high, 1.8 mm wide. Legs ( Fig1 , 2 C): fore femora 2.6 mm long in average; mesofemora 2.7 mm long, mesotibiae about 3.5 mm; fore tibiae with 6 spines and mesotibiae with 4 spines preserved on ventral side; hind femora dilated, about 8.3 mm long, maximum width 2.0 mm, with pinnate veins; upper genicular lobes prominent; hind tibiae 6.4 mm long in average, with 22 or 23 small outer spines; and two ventral and probably two dorsal apical spurs; hind tarsi three-segmented, first segment has four or more denticles on dorsal margins and an apical spur discernible. Wing s ( Fig 1 , 2 D): wings strongly overlapped; about 17.9 mm long; ScA long and slightly S-shaped, reaching anterior margin close to mid-length of wing, distal of the origin of CuPa; ScP long, reaching anterior margin basal of MA1 reaching posterior wing margin; RA simple, RP pectinate with 5 branches reaching wing apex; MA forked into MA1 and MA2 basally, nearly at the level of ScA reaching anterior wing margin; CuPa forked into CuPaa and CuPab at its midlength, slightly distal of origin of MA1; CuPb simple and fuse with AA1 distally. Abdomen ( Fig 2 B): subgenital plate in lateral view narrow and short, cerci short and conical, about 1.0mm long.

Remarks. Locustopsis rhytofemoralis sp. nov. distinctively resembles other species of Locustopsis due to its basal divergence of MA and three branches of M. Additionally, species of Locustopsis also possess hind tarsi with a first segment that bears denticles on dorsal margin and an apical spine, as well as a pronotum with both a developed lateral lobe and elongated hind lobe. The shape of the pronotum belonging to L. rhytofemoralis sp. nov. looks transitional between that of Locustopsis and Paralocustopsis. The length/width ratio of L. rhytofemoralis ’s pronotum is higher than either L. karatavica or L. bucklandi , but lower than Parapleurites sp. Sharov 1968. The apex of its hind lobe is not distinctly pointed. Besides, the hind leg of L. rhytofemoralis sp. nov. is similar to L. bucklandi that the femur is longer than tibiae, and more robust than in other species. Although some information on wing venation is absent due to incomplete preservation and strongly overlapped wing pairs, it differs from all other locustopsid species by virtue of its long ScA which reaches the anterior margin near mid-length of wing and MA forked into MA1 and MA2 at the level of the origin of CuPab.

Discussion. Why have there been so few fossil grasshoppers described from China and, more specifically, from the Jurassic ? There are more than 30 known ensiferan species with thousands of specimens reported from Middle Jurassic of China (Ren et al. 2012), but only one caeliferan specimen is currently known. Tan & Ren (Tan & Ren 2002) and Zheng (Zheng 2005) assumed that Yanliao biota and Jehol biota corresponded to great ancient lake basins which were surrounded by hygrophilous plants; more distant from the lakes, the climate was mild and dry. Therefore, one interpretation can be proposed that these caeliferans might have preferred dry habitats and not lived as close to the water as those ensiferans, thus they were essentially an ecologically foreign element in the environment of sedimentation. Plus, the distribution of these grasshoppers might be narrowed by the vegetation types. These factors might led them had a rather lower chance to be fossilized in these lacustrine deposit.

Figures

FIGURE 1. Locustopsis rhytofemoralis sp. nov., CNU-ORT-NN 2011010 P: A. photograph of habitus (dry-ethanol composite); B. drawing of habitus.

FIGURE 2. Drawings of holotype specimen in detail: A. head in lateral view; B. abdomen; C. hind tibiae and tarsi; D. left forewing. For list of abbreviations, see text.