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Cephalodiscus graptolitoides Dilly, 1993  

Piotr Mierzejewski
Cephalodiscus graptolitoides was erected by P.N. Dilly (1993) as 17th Recent species of the genus Cephalodiscus
M'intosh, 1882 of the order
Cephalodiscoidea (family Cephalodiscidae). The type specimens of this form were
colected in the region of the island of Lifou (New Caledonian Islands) in February 1989. They were found encrusting
the surface of the tubes of
Vermiliopsis associated with Dendrophylia.
According to P.N. Dilly, "The specimens are orange in colour, consisting of a flattened crust of tissue containing
within it many separate sacs each containing a single adult zooid. The surface of the colony is remarkable for a series
of needle-like spines. These spines are up to 3.5 cm in length tapering from a maximum diameter about 0.5 mm at the
base. They extend outwards at right angles to the surface of the encrusting coenecium and intercoenecial tissue."
ABSTRACT of P.N. Dilly's paper:

"A new species of pterobranch has been found that
has features that could resolve the longstanding
arguments by palaeontologists about how the fossil
graptolites produced their elaborate extra-corporeal
homes. Many complex and biologically highly
unlikely solutions previously proposed can be
simplified. This animal is probably classifiable as a
graptolite and thus a living fossil, representing a
group thought to be extinct for 300 million years."

Dilly, P.N. 1993. Cephalodiscus graptolitoides sp.nov. a
probable extant graptolite.
Journal of Zoology. London. 229,
P.N. Dilly's opinion on Cephalodiscus graptolitoides
was discussed in following papers:

Dilly, P.N. 1993. When is a graptolite not a graptolite? -
Lethaia 27:34.
Maletz, J. & Erdtmannn, B.-D. - Lebende Graptolithen?
- Leider nicht!.
Paläontologie Aktuell 32: 50-51.
Mierzejewski, C. & Kulicki, C. 2002.
Discovery of
Pterobranchia (Graptolithoidea) in Permian. - Acta
Palaeontologica Polonica
47, 169-175.
Rigby, S. 1993. Graptolites come to life. -
Svitil,K. 1993. It's alive, it's a graptolite. - Discover 14,
Urbanek, A. 1994. Living non-graptolite. -
27:18.Urbanek, A. 1994. When is a pterobranch a
graptolite ? -
Lethaia 27:324.

Graptolite Net
edited by
Piotr Mierzejewski, the Count of Calmont F.R.C.
Since 2002
P.N. Dilly's diagram suggesting the
mechanism for the secretions of the spines by
the zooids during excursions from their
coenecial tubes.