A HUGE and very uncommon Phyllocarid with soft bodied appendage preservation! This appendage arm was used for balance and is very well preserved.
Phyllocarids have a prominent bivalved carapace covering most of the narrowly-segmented body, which has many trunk limbs and a distinctive two-bladed telson. The sub-oval carapace has a straight dorsal hinge line with a pointed spine at each corner. The carapace surface is smooth except for a narrow border along the margin. The bivalved carapace covers most of the head and the anterior part of the body, extending partly over the lateral side of the animal. There is no evidence of eyes in this animal.
Phyllocarids are considered to represent either a stem-lineage euarthropod (Budd, 2002; 2008) or a primitive branchiopod crustacean (crown-group arthropod) (Resser, 1929; Hou and Bergström, 1997; Briggs et al., 2008), perhaps closely related to Marrella (Briggs et al., 1992; Wills et al., 1998).