Peytoia infercambriensis

Peytoia infercambriensis is a species of hurdiid formerly assigned to the genus Cassubia. It is known from drillcore material that was collected from the Lower Cambrian of Kashubia, Poland.

The species name is derived from the Latin words for "Lower Cambrian". The former genus name Pomerania refers to the Latinized name for Pomorze, a region of northern Poland. The replacement name for the preoccupied genus, Cassubia, is derived from the Latinization of Kaszuby, the region in Poland where the holotype specimen was discovered.

The holotype—and only—specimen was recovered from the Kościerzyna borehole, in the Lower Cambrian Zawiszyn Formation. It was described by Kazimiera Lendzion in 1975 and given the name Pomerania infercambriensis, a name which soon proved to be preoccupied by a Middle Jurassic ammonoid. In her initial description, Lendzion interpreted the fossil as preserving 11 thoracic segments and a chelicera of a Leanchoilia-like arthropod. Subsequent study identified it as an anomalocaridid-like frontal appendage. At first, the portion originally identified as thoracic segments was interpreted as representing the base of an elongate appendage, but it appears to be the body of an indeterminate arthropod.

Peytoia infercambriensis may represent a transitional form between taxa with two rows of similar ventral spines such as Anomalocaris pennsylvanica and taxa with highly differentiated ventral spines such as Peytoia nathorsti. It bears particular similarity to Anomalocaris pennsylvanica and Tamisiocaris borealis.

The frontal appendage was made up of at least 18 segments and had long, straight ventral spines. It is not known whether the ventral spines were paired like in most related taxa. On the anterior edge of the spines were minute serrations which may form the bases of setae.

If the ventral spines possessed setae, Peytoia infercambriensis may have used its frontal appendages to filter through fine sediment.