Data from: The Collins’ monster, a spinous suspension-feeding lobopodian from the Cambrian Burgess Shale of British Columbia

Lobopodians, a paraphyletic group of Palaeozoic vermiform animals bearing
metameric appendages, are key to the origin of extant panarthropods. First
discovered in 1983 on Mount Stephen (Yoho National Park, British
Columbia), the Cambrian (Wuliuan) Burgess Shale lobopodian nicknamed
“Collins’ monster” is formally described as Collinsovermis monstruosus
gen. et sp. nov. A formal systematic revision of the poorly known
lobopodian Acinocricus stichus from Utah is also provided. The body of
Collinsovermis is plump and compact, lacking space between lobopod pairs
but shows the diagnostic suspension-feeding characters of luolishaniid
lobopodians. The six anterior lobopod pairs are elongate, adorned with
long and slightly curved ventral spinules arranged in a chevron-like
pattern. The eight posterior lobopod pairs, which attach to a truncated
body termination, are stout and smooth, each terminated by a single strong
recurved claw. Each somite bears a pair of dorsal spines; somites 4 and
posteriad bear an additional median spine. The spines on somites 1–3 are
much shorter than the spines on the remaining somites. The head is short,
bears a pair of antenniform outgrowths, and is covered by an oblong
sclerite. Collinsovermis plus Collinsium and Acinocricus comprise a
sub-group of stout luolishaniid lobopodians with remarkably long spinules
on the front lobopods, interpreted here as a clade (Teratopodidae). This
clade is distinct from both the comparatively slenderer Luolishania and a
sub-group composed of Facivermis and Ovatiovermis with posterior lobopods
reduced or absent. Luolishaniids were mostly sessile forerunners of
arthropods that had coupled efficient suspension-feeding devices and, as
in Collinsovermis defensive features.