Haichim Zhang

Hexagenitidae of the order Ephemeroptera, is very important in che correlación of non-marine strata in East Asia, its nymphs, with abundant individuals, lived in the warm, shallow and stagnant waters near the shore, crawling on the bottom or swimming in the waters and preying on other aquatic insects. The adults lived on land and were short-lived and poor fliers. This mayfly is distinguished from other components of Hexageniridae by irs large size, and is a cecal branch in the evolution of rhis family in rhe late Mesozoic,

Aeschnidiitm beishankowense (Fig. 73) is a kind of large dragonfly referred to Aeschnidiidac* of Odonata. Its larvae are numerous, and lived in a similar environment to that of Ephemeropsis trmtal'u, They preyed on other aquatic insects dominated by wigglcrs of mosquitoes and flies or small, young aquatic insects and fishes. The adults lived upon land as long-lived and excellent fliers.

72 Adult mayfly Ephemeropsis trisetalis, about 60 mm long.

■n 73 Adult, female dragonfly Aeschnidium hetshankowense. about 130 mm wide when wings stretched. Red arrow denoting the long ovipositor.

■n 73 Adult, female dragonfly Aeschnidium hetshankowense. about 130 mm wide

This large species influences, directly or indirectly, on the quantity variation of almost all other insects, or even on their rise and fall, for both larvae and adults of this species are the largest carnivorous insects of the Jehol entomofauna. Its con-generic relative has been found from the lower Tithonian in Solnhofen, Germany, and thus it plays an important role in ascertaining the age of the Jehol insect fauna. The family Aeschnidiidae was an interesting group in the Late Jurassic—Early Cretaceous, and as the typically early-staged representative of this group. This Chinese species shows some primitive characteristics such as the dense veins and much small cells on fore- and hind-wings.

when wings stretched. Red arrow denoting the long ovipositor.

Mesolygaeus laiyangensis (Fig. 74), a medium or small-sized aquatic bug belonging to an extinct family Mesolygaeidae referable to Heteroptera within Hemiptera, plays an important role in the correlation of non-marine strata in East Asia. Both juveniles and adults, with abundant individuals, lived in the warm, shallow and stagnant waters near the shore, crawling and swimming in the waters, but sometimes they also disembarked. The adults could fly off the waters, preying on other small aquatic insects, such as the wigglers of mosquitoes and flies. This species only lived in the late Mesozoic but was closely related to extant shore bugs (the family Saldidae), and both of them

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wait 74 Saldoid bug Mesolygaeus laiyangensis, about 7 mm long, from Nanligezhuang locality (Laiyang Formation) in Laiyang, Shandong.

175 Chaoborid mosquito Chironomaptera gregoria, about 6 mtn long, from Nanligezhuang locality (Laiyang FormarionI in Laiyang, Shandong.

176 Brachyceran fly Protanemestrius jurassicus, about 13 nun long, red arrow denoting ihe proboscis. (Courtesy: Dong Ren/CNU)

177 Sketch drawing ol Protanemestrius jurassicus. (Courtesy: Dong Ken/ CNU)

matid earwig, aboui 20 mm long.

lower bug, about 10 mm long matid earwig, aboui 20 mm long.

Katydid, about 25 mm long.

Katydid, about 25 mm long.

i84 Cupedid beetle Natocupes laetus, about 15 mm long. 186 Snakefly Alloraphidia longistigmusa. about 20 mm long.

85 Dung beetle, about 20 mm long.

187 Chaoborid mosquitos Chironomaptera vesca. about 10 mm long,

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belong to the same superfamily Saldoidea. As for lifestyle, however, the former could live in water and is regarded more primitive than the latter that are often seen along shores of ponds or lakes.

Cbironomaptera gregaria (Fig. 75), belonging to phantom midges (the extant family Chaoboridae), is a small mosquito. It is also an important component in the correlation of non-marine strata in East Asia. Their wrigglers, with abundant individuals, lived in the warm, shallow and stagnant waters near the shore, wriggling in the waters. The adults were terrestrial, flying over the marshes where plants were prosperous. The species belongs to the Chironomapterinae, a Mesozoic extinct subfamily, the phylogenic position of which in the family Chaoboridae remains unclear. As the food of other medium-sized and small predatory insects, these wrigglers were important in the ecological chains of the lacustrine systems in the period they lived.

Though not large in quantity, the Jehol probably flower-associated insects are of great importance to the Biota, giving an example of co-evolution between these ancient probable pollinators and earliest representatives of angiosperms (flowering plants). The identification of the flower-related

91 Ichneumon fly Tanychora beipiaoensis, about 7 mm long.

insects gives further proofs that the flowering plants were possibly present, though not dominant, in the Biota from the Late Jurassic—Early Cretaceous in the northeastern part of China. Some of the probably pollinating insects of the Jehol Biota are referred to the order Diptera, e.g., Prntonemestrinsjurassicm (Figs. 76, 77), Protonemestrins beipiaoensis, Florinemestrius pnlcherrimus, and flowering bug (Fig.78), etc. The characteristic feature of these insects is with special nectaring mouthparts (proboscis) rhat are similar ro modern con-familial pollinating taxa. However, the probability rhat these insects fed, in fact, on juice of plants or blood of orher animals could not be excluded. Besides the aforementioned taxa, materials of other Jehol insects (Figs. 79~93) were also inrensively collected.

In the Jehol Biota, spiders were low in diversity and nor rich in abundance, with representatives in some species of the family Araneidae referable to the order Araneida within the class Arachnid a (Fig. 94). They usually lived amongst wood branches or leaves in the forests, spinning orb webs that were vertical or horizontal or inclined depending on the spatial relationships of the supporting objects. Usually, the spider sat on the center of the web from dusk to dawn, and hid between plant stems or leaves near its web during the day, preying on many kinds of small and medium-sized winged insects.

(Except where indicated, all fossils in this chapter were collected from the Huangbanjigou locality of the lower part of the Yixian Formation in Beipiao, Liaoning)

Wi/,94 Orb-web spider, about 10 mm long.

92 Pelecinid wasp Scorpiopelecinus versatMs, about 15 mm long.

sen93 Digger wasp Pompiloperus s'p.. about 15 mm long.

Wi/,94 Orb-web spider, about 10 mm long.

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