The Burgess Shale

Ctenorhabdotus capulus

A comb-jelly with a lantern-like body and 8 sets of 3 comb-rows

Reconstruction of Ctenorhabdotus capulus.

© Marianne Collins

Taxonomy:

Kingdom: Animalia
Phylum: Ctenophora
Class: Unranked clade (stem group ctenophores)
Remarks:

Ctenorhabdotus is regarded as a very primitive ctenophore, possibly representing a stem-group member (Conway Morris and Collins, 1996).

Species name: Ctenorhabdotus capulus
Described by: Conway Morris and Collins
Description date: 1996
Etymology:

Ctenorhabdotus – from the Greek ktenos, “comb,” and rhabdotos, “striped,” in reference to the pronounced striped-like appearance of the comb-rows.

capulus – from the Latin capulus, “a handle,” in reference to the prominent aboral capsule-like element.

Type Specimens: Holotype –ROM50822 in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

Period:
Middle Cambrian, Bathyuriscus-Elrathina Zone (approximately 505 million years ago).
Principal localities:

The Walcott and Raymond Quarries on Fossil Ridge.

History of Research:

Brief history of research:

Ctenorhabdotus capulus was described by Conway Morris and Collins in 1996 and no additional studies have been published since then.

Description:

Morphology:

Ctenorhabdotus is ovoid in shape and bears 24 comb-rows. The top (aboral) and bottom (oral) surfaces are relatively flat. The comb-rows are organised in 8 sets of three, with the central row being much shorter than the two flanking ones. Each group of three comb rows converges towards the aboral side to form 8 strands. The oral region is well developed with an undulating margin. There is a small capsule-like structure on the aboral side of the animal which is thought to include an apical organ and statocysts.

Abundance:

Ctenorhabdotus is rare, known from about two dozen specimens, mostly from the Raymond Quarry. In the Walcott Quarry, this species comprises only 0.01% of the specimens counted (Caron and Jackson, 2008).

Maximum Size:
70 mm

Ecology:

Life habits: Mobile, Nektonic
Feeding strategies: Unknown
Ecological Interpretations:

The presence of comb-rows suggests the animal was an active swimmer. Its mode of feeding is more conjectural as the mouth is not well preserved and there is no evidence of tentacles.

References:

CARON, J.-B. AND D. A. JACKSON. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.

CONWAY MORRIS, S. AND D. COLLINS. 1996. Middle Cambrian ctenophores from the Stephen Formation, British Columbia, Canada. Philosophical Transactions of the Royal Society of London, Series B, 351: 279-308.

Other Links:

None