Macrurous Decapoda from the Luoping Biota (Middle Triassic) of China

Abstract

A large collection of macrurous decapod crustaceans is recorded from the middle–late Anisian (Middle Triassic) Guanling Formation in Yunnan Province, China. A remarkable assemblage of over 20,000 vertebrate, invertebrate, and plant fossils collectively referred to as the Luoping Biota has been collected from quarries in the vicinity of the city of Luoping. Among these, arthropods including the decapods are the most common element although articulated fish and reptiles are also common. The decapods represent new taxa, includingKoryncheiros luopingensisn. gen. n. sp. within Clytiopsidae, a newly elevated family within Erymoidea;Tridactylastacus sinensisn. gen. n. sp. within Glypheidae; andYunnanopalinura schramin. gen. n. sp. within Palinuridae. A single specimen has been referred to Palinuridae sp.Koryncheiros luopingensisexhibits a unique cheliped architecture and the second through fourth chelipeds are subchelate, an extremely rare configuration.Tridactylastacus sinensisalso exhibits subchelate closures of pereiopods 2–4, but it bears a distinctive subchelate first pereiopod with an intercalated spine between the fingers on the distal margin of the propodus.Yunnanopalinura schramirepresents the oldest occurrence of Palinuridae and Achelata. Collectively, these expand our knowledge of Chinese decapods significantly in that only six species of fossil decapods have been described previously from the country.