Parapeytoia

Parapeytoia is a genus of extinct arthropod that lived over 530 million years ago (Cambrian Stage 3) in the Maotianshan shales of prehistoric China. It was interpreted as an anomalocaridid (radiodont) with legs,[1] but later studies reveal it was a megacheiran,[2][3][4][5] a group of arthropods which are no longer thought to be closely related to the radiodonts.[6][7]

Interpretations on Parapeytoia yunnanensis as an anomalocaridid (radiodont, A) and megacheiran (B) respectively. Red parts indicating suggested anomalocaridid-like features with questionable affinity. Dark grey indicating other structures unambiguously belong to this species.

Parapeytoia Temporal range:
Holotype of P. yunnanensis, part and counterpart
Ventral structures of Parapeytoia yunnanensis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	†Megacheira
Family:	†Jianfengiidae
Genus:	†Parapeytoia Hou, Bergström & Ahlberg, 1995
Species:	†P. yunnanensis
Binomial name
†Parapeytoia yunnanensis Hou, Bergström & Ahlberg, 1995

Parapeytoia is known from a few incomplete fossil materials with part of its ventral structures preserved. The frontmost appendages were a pair of great appendages that had a peduncle and 4 spines on each of them, a characteristic feature shared by other megacheirans such as Yohoia and Fortiforceps.[8] Behind the great appendages were 2 or 3 pairs of short appendages, and numerous pairs of well-developed biramous appendages, each formed by a basipod with spiny gnathobase, lobe-like exopod and leg-like endopod with 8 segments. A narrow sternite associated between each of those appendages.[1]

Some features originally interpreted as anomalocaridid-like are more or less questionable, such as radial sclerites interpreted as its mouthparts have since been assigned to another genus of animal, Omnidens.[9]

Parapeytoia was in all likelihood a benthic feeder, spending most of its time on the ocean floor hunting (or possibly scavenging) for prey.[2]