Jiangyong Zhang Fan

Fishes are che most abundant fossils in the Jehol Biota. They are counted tens of thousands. The scientific study on fossil fishes of Jehol Biota in western Liaoning started in the second half of the 19th century when II. E, Sau vage, a French anatomist, named the specimens from northern China as a new species. Prolebias davidi, of Cyprinodontidae. Nearly hall a century later, Amadeus W. Grabau, an American paleontologist, described Lycoptcra johtdensis ami L.jahoknsis var. minor in his book Stratigraphy of China in 1928. Subsequently, Kazuo Saito and Fuyuji Takat, from Japan, also studied fossil fishes from the area. The hrst work published by Chinese scholars is the monograph Lycopterid Fishes from North China by Hsien-ting Liu and others. In recent years, many new fossil fishes were found in the area. To date, seven genera of the fossil fishes o( Jehol Biota have been published, including Peipiaoste/ts, Yanosteus, Protopsephnrm, Sinamia, Lungdekhthys, LycopUm, and Jinanichthys.

Peipiaosleus, Yanostens, and Protopstpburus are fishes belonging to

Acipenseriibrmes (sturgeons), Chondrostei, Actinopterygii. The earliest acipenseriform fishes were found from the Early Jurassic of Britain and Germany. But the Late Jurassic-Early Cretaceous ones were only found in Central Asia and the north of East Asia. Both fossil and extant acipenseriforms appear only in Holarctic and live in fresh waters or in anadromous migration style since Early Jurassic. Acipenseriforms are predators and prey on planktonic animals in juvenile and soon after acquire a benthic life. Adapting themselves to rlias lifestyle, they develop an elongated jaw and an inferior mouth. The preys are primarily shellfishes, mollusks and small fishes, including certain kinds of their own. Acipenser sinensis (Fig. 95) is an endemic-species of China and is a national treasure. It is a large anadromous migration fish, with an individual weighing up to 550 kg. The juveniles live in the littoral of the Eastern China Sea antl then migrate up the rivers ro spawn. The spawning areas are mainly in the Yangtze anil Pearl Rivers.

Peipiaoiteus and Yanosteus are referred to a newly erected fossil family

95 Acipenser sinensis, a large anadromous migration fish, with juveniles living in the littoral of eastern China and adults migrating mainly to the Yangtze and Pearl rivers to spawn. (Courtesy: IHB)

96 Peipiaosteus pan), the first fossil acipenseriform fisli found in China, usually less than one meter. A very well preserved specimen (Leftl, with impressions of muscles and roes, from Huangbanjigou locality (lower part ofYixian Formation) in Beipiao, Liaoning. and a close-up view of its digestive tract impression iRight. denoted by a red arrow). (Photo: 1VPP|

ma 97 Yanosteus longidorsalis, characterized by an extremely long dorsal fin (denoted by a red arrow) nearly up to one third of its total body length. The fish may reach one meter in standard length (Photo: IVPP)

Peipiaosteidae. Peipiaosteus (Fig. 96), from Yixian and Jiufotang Formations of Beipiao, Liaoning and Fengning, Hebei, is the first fossil acipenseriform found in China, with a relatively small body size usually not exceeding one meter. Judging from the specimens preserved with roes, the fish probably became mature when its body reached 30 cm long. Peipiaosteus differs from other acipenseriforms in the absence of the caudal fulcra on its caudal fin.

Yanosteus (Fig. 97) was discovered in Lingyuan, Liaoning and Fengning, Hebei. The remarkable feature of the fish is its extremely long dorsal fin, nearly up to one third of its total body length. Although approximately fusiform in its body shape, Yanosteus has a relatively straight dorsal margin of the body. The length of the smallest individual is about 20 cm whereas a large specimen may reach one meter long. No specific information (such as roes) can be used to determine the adult size.

Protopsephurus (Fig. 98) is a member of a recent family Polyodontidae (paddlefish). It was collected from Lingyuan, Liaoning, with a length of approximately 10 cm in smallest individuals and over one meter in large specimens. Judging from the matured skeletons, Protopsephurus could be the smallest in body size among the genera of Polyodontidae. This genus is the earliest fossil record of the family. An extremely long rostrum, a series of rostral splints and spine-fringed scales are the most prominent features of the family. Psephurus is the only extant polyodontid in China who lives in the drainage of the Yangtze River and littoral region of the East China Sea whereas Protopsephurus is a stem-polyodontid closely related to Paleopsephurus, a Late Cretaceous sturgeon from North America. The living paddlefish is commercially an important freshwater fish. It has naked body surface and spoon-like rostrum and is thus also called duck-mouthed sturgeon. The paddlefish eats mainly zooplankton, and is adapted to a wide range of temperature (2~37°C). A native in the drainage of the Mississippi in the United States, the paddlefish has been growing very well in China since it was introduced here.

Sinamia (Fig. 99) is supposed to belong to a fossil family of its own, Sinamiidae (Amiiformes). The genus was named by E. A. Stensio, a Swedish paleontologist, based on the materials from Mengyin, Shandong, China collected by Xi-chou Tan from China and O. A. Zdansky from Austria in 1923. Sinamia was found in the Yixian and Jiufotang Formations in Yixian, Chaoyang, Liaoning and also in Shaanxi, Gansu, Ningxia, Inner Mongolia, Anhui and Zhejiang. The wide distribution of Sinamia implies the possible connections between the drainages of the aforementioned places.

Sinamia is very similar to, but more primitive than, the living bowfin Amia. Fossil bowfins were usually found in marine deposits in many parts of the world; in contrast, they have occurred only in freshwater deposits of the Early Cretaceous of both North and South China and early Tertiary of North America. The only surviving species of bowfin {Amia calva) lives in fresh waters of eastern part of North America and is called a "living fossil". Normally, Amia inhabits sluggish, clear, lowland fresh waters preferably rich in vegetation. It can withstand high temperature, gulp and expel air at the surface, and is even known to aestivate. With its strong and sharp teeth, Amia is a voracious predator. The juvenile Amia feeds on smaller animals such as insects, insect larvae, ostracods, other Zooplankton and phytoplankton, but after reaching 10 cm long, it begins to feed on other fishes. Adults also eat crayfish. The teeth of Sinamia are similar to those of Amia. Their food sources might be also similar.

Lycoptera (Fig. 100) is the most frequently met fish from the Jehol group. It is a small fish referred to a group called teleosts that reach the greatest diversity among the recent vertebrates. The fish was found mainly in the Yixian Formation in west Liaoning. Endemic to East Asian, Lycoptera was discovered only in Siberia, Mongolia, Korea and northern China from the late Mesozoic. The genus was named by a German anatomist, J. Müller, based on the materials from Transbaikalia of Siberia. The study of Lycoptera in China began with the work of Henri E. Sauvage on the fossil teleosts collected from North China (probably Daxinfangzi, Lingyuan, Liaoning). The fish was named by Sauvage as Prolebias davidi and was referred to Lycoptera by A. S. Woodward (a British paleontologist) afterwards. From then on, many scientists of both China and foreign countries have worked on the genus and named about 16 species. Most species of Lycoptera had tiny teeth and ate plankton, but L. sinensis, L. gansuensis and L. muroii bore relatively large teeth and were capable of preying on small insects and their larvae. Lycoptera is usually well-preserved, possibly because they were buried in situ. Entombed in great density, the fish seems to have a habit of swimming in shoals (Fig. 101).

Lycoptera is also the earliest fossil teleosts discovered in China. The strata bearing Lycoptera were previously considered the Late Jurassic. The vanishing of Lycoptera was regarded as the indicator of the boundary between the Jurassic and Cretaceous. But workers studying ostracods, fossil plant and some other invertebrates have long regarded the strata as the Early Cretaceous. The

98 I'rotopsephurus liui. the earliest fossil polyodontid found to date and more than one meter long in large specimens, is a distinct relative of Psephurus living in the drainage of the Yangtze River and littoral region of China. This is a well-preserved specimen from Dawangzhangzi locality (middle part of Yixian Formation) in lingyuan, Liaoning, showing distinct scales and caudal skeleton. (Photo: IVPP)

99 Sinamia. found from freshwater deposits of both North and South China, is a distinct relative of living bowfin with strong and sharp teeth, and a voracious predator. This specimen is about 50 cm long. (Photo: IVPP)

■«100 Lycoptera, the most common fossil vertebrate in western Liaoning and the earliest teleost found in China, is an important member of thejehol Biota and only distributed in Hast Asia. This specimen is about 12 cm long. (Photo: IVPP)

■«100 Lycoptera, the most common fossil vertebrate in western Liaoning and the earliest teleost found in China, is an important member of thejehol Biota and only distributed in Hast Asia. This specimen is about 12 cm long. (Photo: IVPP)

debate has I as red for decades and drawn much attention of geologists and paleontologists. From in-depth studies on Lycop!era in recent years, many palcoichthyologists considered that the fish existed in the Late Jurassic to Early Cretaceous.

Lycoptera became the earliest known osteoglossomorph fish after the British ichthyologist P. H. Greenwood suggested a close relationship between the genus and the superorder Osteoglossomorpha. Fossils of the superorder were found from the Early Cretaceous to Oligocene in nearly all the main continents except Antarctica, but early osteoglossomorphs were mostly recovered from China. Fossil fishes similar to Lycoptera found from the Mesozoic terrestrial deposits of China were frequently referred to the superorder. Up to now, about 25 genera and 50 species of them were reported from China.

The superorder Osteoglossomorpha (bonytongues) is a very early branch of teleosts. The number of its fossil genera far exceeds the extant ones; however, the reverse is the case with most other teleost groups. Living bonytongues are exclusively fresh-water. The Southeast Asian Scleropages (Fig. 102) is the most prized and expensive osteoglossomorphs. Because of the two

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Lycaptera is usually preserved in great density. The specimen was found in Daxinfangzt locality (middle part ofYixian Formation! in Ungyuan, l.iaoning. (Photo: (VHP)

SclempagesJonmsus ("fortune fish"), a livinjt ostcoglossoid fish, is the mosi prized and «pensive osieoglossomorphs, a group also includes Lycoptera and Jinawchthyi as primitive members. (From: http: w ww.arnw.ina. com.tw)

Jinaafchthys, very similar to Lycoptera, was found mainly from the Jiufotang Formation in western liaoning This specimen is about *J cm long, (Phoio: IVPP)

barbels. glorious large st ales and old history nt H>l fish, it w is railed "dragon fish" in China and was believed to have the power to ward off evil and to bring luck and fortune,

Jmtutchthyi d ig. 103) was mainly found from rhc Jiufotang Formation and was described by Fenu-zhen M.i and Jta-ru Sun based on the Inssils from southern Jilin Province. The authors believed thai the speiimens from Jilin were similar to L)u>f>ter<i leneitvpbtt/jit but different from other species of the genus. Therefore, they gave a new generic name,Jinanubtb)\. (n both Lycopttr./ trmgiaphaltn and the specimens from Jilin.

Extant osteogloSsomorphs survived in the tropical or subtropical fresh carers ot North America, South America, Australia, Southeast Asia. India, anil Africa. No consensu*lias ix-en reached by ichthyologists up to now about the interpretations ot the transoceanic distribution ol those freshwater fishes.

Lycoptera, Jmanichihvs and other fossils ot the superordcr found in ( hina are the earliest known osteoglossomorphs. Therefore, some paleoichthyologists suggested that East Asia might be the ancestral origin center of osteoglossiimorphs. An African origin was also suggested. In recent years, some researchers argued that the transoceanic distribution was resulted from the spin tit .m ancestral land blixrk according to vicariance principle. That is to say. the early evolution of osteoglossomorphs had already finished before the last break ot the superconrinent Pangea.

Lottgdtkbihy was another teleost found in western l.iaoning. It was collected from Jiufotang Formation of Yixian and Metsh.in. Its total body length may reach 23 cm. The original name was given by Zhi-theng Liu, based i>n the specimens from Longde, Ningxi.i and Yikezhaomerjg, Inner Mongolia.

Callobatrachus

'7104 Holotype of Callobatrachus sanyanensis (snout-pelvis length 94 mm), a discoglossicl frog, from Sihetun locality (lower part of Yixian Formation, Early Cretaceous) in Beipiao. Liaoning. (Photo: IVPP)

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