Habelia

Habelia is a genus of extinct arthropod from the Middle Cambrian, thought to be one of the earliest known relatives of chelicerates. Its fossils have been found in the Burgess Shale in British Columbia, Canada. Fifty-four specimens of Habelia are known from the Greater Phyllopod bed, where they comprise 0.1% of the community.

== Description == The body is divided into two main segments. The cephalon ("head")/prosoma with seven segments/8 somites, and the trunk with 12 segments, making for a total of 19 body segments. The body is around in length excluding the long telson that terminates the body. The head, which is 25% wider than it is long, makes up about 30% of the total body length, and has a bulging shape, with triangular genal spines projecting outward at its edges. It housed the stomach of the animal. The head bore a pair of spherical compound eyes, which were accommodated by notches in the head shield. A hypostome-labrum complex was present, with the mouth openling vertically close to the front of the head. The first pair of appendages was very short and probably flexible, this was followed by 5 pairs of appendages that bore large gnathobases (modified basipod/base of the appendages used to process food), increasing in size posteriorly which bore staggered rows of strongly sclerotized teeth on their inner edge. The limbs were biramous (divided into two branches), The endopods (lower branch) of these limbs increased in size posteriorly, and had seven segments/podomeres, with the terminating segment being a claw, with podomeres 5 and 6 having borne a brush of inward facing setae (hair-like structures). The exopods (upper branch) of these limbs were elongate and thin rami, increasing in size posteriorly, each composed of 7 or more podomeres, which bore setae at the segment joints.