Megadictyon

Megadictyon is a genus of Cambrian lobopodian with similarities to Jianshanopodia and Siberion. The name of the genus is occasionally mis-spelt as Magadictyon.^[1]

Megadictyon Temporal range: Cambrian Stage 3 PreꞒ Ꞓ O S D C P T J K Pg N
Reconstruction of Megadictyon cf. haikouensis
Scientific classification
Kingdom:	Animalia
Phylum:	Lobopodia
Class:	†Xenusia
Order:	†Siberiida
Family:	†Siberiidae
Genus:	†Megadictyon Luo & Hu, 1999
Species:	†M. haikouensis
Binomial name
†Megadictyon haikouensis Luo & Hu, 1999

Description

Megadictyon is a large lobopodian, with a body length (excluding appendages) possibly up to 20 centimeters in total.^[2] The head has a pair of robust frontal appendages^[3] associated with rows of spines and terminal claws.^[2] Located on the underside of the head is a radiodont-like mouthpart formed by multiple layers of plates and tooth-like structures.^[2] The trunk is wide and annulated, with a pair of well-developed lobopodous limbs on each body segment. Only 8 segment/limb pairs are countable in the incomplete fossil materials which are lacking the posterior region, so it may have had more (possibly up to 11 to 13) in nature.^[2] It also has pairs of digestive glands similar to those of basal arthropods.^[2][4]

Phylogeny

Phylogenetic position of Megadictyon according to Pates et al. (2022).^[5]

	Aysheaia Onychodictyon Tardigrada Onychophora Megadictyon Jianshanopodia Hadranax Kerygmachela Pambdelurion Utaurora Opabinia Aegirocassis Peytoia Schinderhannes bartelsi Cambroraster Hurdia Amplectobelua Lyrarapax Anomalocaris Houcaris Deuteropoda