Taxonomy of fossil Palaeontinidae from the Late Mesozoic in Northeast China (Insecta: Heimptera: Cicadomorpha)

Authors: Ying Wang1   Dong Ren2* 

Author’s affiliations:

1 Beijing Museum of Natural History, 126 Tianqiao South Street,Beijing100050,China;

2 College of Life Sciences, Capital Normal University, 105 Xisanhuanbeilu, Haidian District, Beijing 100048,China

E-mail address: wangying_527@126.com; rendong@mail.cnu.edu.cn

Key words: Palaeontinidae, Taxonomy,Mesozoic,China

Palaeontinidae is an extinct family of Hemiptera, with existed from the Triassic to the Mid Creatceous. Until now, it included 44 genera and 110 species, distributed in the Kyrgyzstan (Triassic of Issyk-kue and Sulucta, Jurassic of Sai-Sagul), Turkmenistan (Jurassic of Karabas-Tau), China (Jurassic of Xinjiang, Hebei, Gansu and Inner Mongolia; Late Jurassic to Early Cretaceous of Liaoning), Russia (Jurassic of Iya, Ust-Baley and Irkutsk, Early Cretaceous of Transbaikalia), Tadzhikistan (Jurassic of Shurab), Kazakhstan (Jurassic of Turgay), Australian (Triassic of Ipswich), South Africa (Triassic of Bird’s River), Brazil (Cretaceous) and Spain (Late Jurassic to Early Cretaceous) (Wang Y et al., 2007a). The extinct family Palaeontinidae had the first appearance in the Middle Triassic of Australian (Evans, 1956). It was abundant in the Jurassic and became extinct by the Mid-Cretaceous (Menon et al., 2005). The distribution of Palaeontinidae is correlated with the abundance of Ginkgoales (Zherikhin and Kalugina, 1985). It is highly improbable that they may feed on phloem of rather thick stems of Ginkgoales.

Mesozoic volcanic activity in easternChinacommenced in the Late Triassic, gradually increased in intensity during the Early and Middle Jurassic. During the Late Jurassic the volcanism was very strong, while in the Early Cretaceous it was weaker and nearly terminated in the Late Cretaceous (Xu, 1990). The Northeast China, especially Jiulongshan Formation of Middle Jurassic and Yixian Formation of Late Jurassic to Early Cretaceous, yield a mass of notable fossils including abounded insects which provide important evidence for study of the origin and early evolution of insects.

Among these abundant insect fossils, the record of fossil of Palaeontinidae are quite common in the insectiferous deposits from the Northeastern China, and often very well preserved and presenting distinct morphological disparity. These valuable materials are the important supplement to the record of world fossil palaeontinid and may aid study of their origin as well as their interactions between insects and plants.

Representatives of extinct Palaeontinidae were huge, moth-like insects, resembling a little, but not related to singing cicadas, which witnessed the rise and fall of dinosaurs. Head with small postclypeus and long rostrum.  Compound eyes and ocelli present. Their wing span ranges 10-36 mm; wings are very often disruptive patterned, and body is often covered with scales or dense hairs (Wang Y et al., 2007a; Wang Y and Ren, 2009). A combination of cryptic coloration and disruptive marking enhanced their camouflage. They constitute 15.5% of specimens in the fossil record of Northeastern China. The known taxonomic diversity of these fossils is relatively high, with 42 species within 17 genera reported from the Daohugou (the Middle Jurassic) and Beipiao (the Upper Jurassic to Lower Cretaceous) strata. Another 14 species within 6 genera reported from the Xinjiang, Hebei andGansuProvince.

It is not very common to find fossil specimens with well-preserved and complete body, forewings and hind wings. Among erected genera of Palaeontinidae, most genera were described and illustrated based on a single forewing or hind wing. Up to now, 15 genera worldwide were established based on complete forewings and hind wings. Different venation pattern of forewings and hind wings is important for generic classification in palaeontinids. Well preserved specimens from Daohugou and Beipiao strata enabled us to fix accurately the characters of the wing and head.

The section atDaohugouVillageis composed of grey tuffaceous sandstone and sandy mudstone. Up to now, in comprises rich animal and plant fossils, at least 130 species of insects have been collected fromDaohugouVillage(Wang Y et al., 2007b). The paleoenvironment reconstructed for this locality is a volcanic region with mountain streams and lakes. The age of Daohugou fossil-bearing beds is Middle Jurassic. With recent discoveries of the fossil genera Daohugoucossus Wang B. et al., 2006 (2006a), Eoiocossus Wang B. et al., 2006 (2006b), Quadraticossus Wang Y. and Ren, 2007, Hamicossus Wang Y. and Ren, 2007, Abrocossus Wang B. et al., 2007, Neimenggucossus Wang B. et al., 2007, Cladocossus Wang Y. and Ren, 2009 and Cricocossus Wang Y. and Ren, 2009, Daohugou area has proven to be one of the most important site for studying past diversity of the Palaeontinidae. By comparison, the Middle Jurassic palaeontinids diversity is greater than those in any other epoch, suggesting that the family probably went into its most prosperous stage in the Middle Jurassic. Their high taxonomic and morphological diversity suggests a high complexity of niche structure and a high level of specialization within the guild.                                                                                            

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