Palaeocambarus is an extinct genus of crayfish discovered in the Yixian Formation in China, with only a single species, Palaeocambarus licenti. It is one of the oldest known fossil crayfish.[1][2][3]
The species was first named by Van Straelen in 1928 as Astacus licenti. In 1999, the species was assigned to the new genus Palaeocambarus, and was placed in the family Cambaridae. In the same publication, the genus and species Cricoidoscelosus aethus was described, and was placed into the monotypic family Cricoidoscelosidae.[1] In 2019, a supposed new species of the spider Mongolarachne, "Mongolarachne" chaoyangensis was described from the Yixian Formation in China.[4] However, in a later publication that same year, when the specimen was subject to fluorescence microscopy, it was shown that the specimen was a forgery using specimen D3088, a specimen of Cricoidoscelosus, as a base, that had been painted to look like a spider, and as such the species was a junior synonym of Cricoidoscelosus.[2] In 2023, a re-evalutation of crayfish from the Yixian Formation found that Cricoidoscelosus was a synonym of Palaeocambarus and that Palaeocambarus could be confidently placed in Cambaroididae, which includes modern East Asian crayfish (Cambaroides).[1]
^ abTaylor, R.S., Schram, F.R. & Shen, Y.B. (1999) A new crayfish family (Decapoda: Astacida) from the Upper Jurassic of China, with a reinterpretation of other Chinese crayfish taxa, Paleontological Research, 3, 121–136.
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