Uaoning Photo Dajian Li CASFormation in Linyuan Liaoning Photo Dongxing Deng NIGP

MB 68 A nearly complete individual (venrral view, 16 mm long) of Liaoningogriphus quadriportitus from Sihetun locality (lower part of Yixian Formation) in Beipiao, Liaoning, showing thorax, abdomen and tail. (Photo: Hai-chun Zhang/ N1GP)

deposits of Las Hoyas, Spain are under description.

A new spelaeogriphacean, Liaoningogriphus quadripartitus, was recently described by Shen, Taylor anil Schram (Figs. 6H—70) from the Yixian Formation in Sihetun, Jianshangou, and Huangbanjigou areas of Beipiao City, and near Dakangpu village of Yixian County, Liaoning Province. Irs body is elongated and cylindrical in outline with a maximum observed length about 20 mm. Thinly sclerocized carapace covers the head and most of the first two thoracomeres. Liamngpgripht/s possesses a very short, broadly rounded rostrum. The antennules are biramous and the antennae uniramous. Thoracopods 2~8 are well developed with endopods. The last six thoracomeres are freely exposed. Very well developed, elongate, biramous pleopods .ire equally present on the pleomeres 1 ~5. The distal protopod margin is sigmoidally curved, with two-segmented exopods and an endopod. The telson possesses two pairs of short, robust median terminal spines and a fine transversal line in its lower middle part. The uropods are more than twice as long as the telson. The exopod has two ovoid segments.

The living spelaeogriphaceans are restricted to the Southern Hemisphere. Conversely, all known fossil taxa are found from the Northern Hemisphere. There is a trend of size reduction: the recent taxa appear to be considerably smaller (about 7 mm long) than the fossil forms (9.4—20 mm long).

Liaoningogriphus is extremely abundant but completely lack of diversity. They are usually preserved in yellowish-gray tuffaceous shales anil siltstones with fine laminated structure and often associated with terrestrial freshwater

wart 69 A nearly complete individual 116 mm long) of Liaoningogriphus quadripartitus in lateral view, from Sihetun locality (lower part of Yixian Formation) in Beipiao, Liaoning. (I'hoto: Da-jian Li/CAS)

mm 70 Reconstruction of Liaoningogriphus quadripartitus in dorsal (a) and lateral (b) aspects. (Courtesy: F. R. ScliranV 7.MLJA)

organisms, such as conchostracans, ostracods, bivalves, gastropods, insects and plants. Three living spelaeogriphacean forms, Spelaeogriphus kpiclops, Potiicora brasilemis and Matigkr/tu mityula, are swiftly swimming animals with rapidly undulating body. They are found in caverned freshwater pools and underground aquifer. However, based on associated conchostracan habits and the shrimp-bearing beds with abundant tuffaceous materials, Liaoningogriphus must have lived in ground-water lakes and pools instead of cave pools or underground water. It was warm temperate-subtropical climatic environments during the late Mesozoic in eastern Asia.






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