Cephalodiscus graptolitoides is a species of sessile pterobranch hemichordate in the genus Cephalodiscus. It was collected off Lifou in New Caledonia at a depth of . The species forms a flattened, encrusting tubarium with long spines.
Description Cephalodiscus graptolitoides forms an encrusting colony containing separate cavities occupied by individual zooids. Its tubarium bears tapering spines that may reach about in length.
The species is placed in the nominate subgenus, Cephalodiscus (Cephalodiscus), whose members lack separate cylindrical dwelling tubes and instead occupy interconnected cavities within a communal tubarium.
Discovery and distribution The species was collected in 1989 during the CALSUB expedition, which explored the bathyal fauna of New Caledonia using the French submersible Cyana. The specimen came from CALSUB dive 9 off Lifou at depth. P. N. Dilly formally described it as a new species in 1993.
Relationship to graptolites Dilly proposed that the structure of the tubarium and its spines indicated that C. graptolitoides might be a living graptolite. This interpretation was later disputed, with subsequent reviews retaining the species within Cephalodiscida.
A 2013 phylogenetic analysis recovered Graptolithina as the sister group of Cephalodiscida and placed the living genus Rhabdopleura within Graptolithina.
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