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Rhabdopleura compacta  Hincks, 1880
Graptolite NetGraptolites & Graptoliters | Rhabdopleuroidea | Cephalodiscoidea | Crustoidea | Tuboidea
At right there are SEM micrographs showing three coenecia of the hemichordate Rhabdopleura compacta collected alive by A.R.D. Stebbing in 1967 while dredging off Stoke Point (depth 21-24 m), South Devon, England. The colonies were attached to the concave surfaces of disarticulated shells of the bivalve Glycymeris glycymeris. For SEM study, they were etched intact from the shell with a weak solution of acetic acid.
     The colonies are about 0,8-2.9 mm in diameter and form irregular, compact and encrusting mats of adhering repent tubes, from which arise 2, 3, or up to 10 erect tubes. A frayed marginal membrane runs around the periphery of the attached part of each coenecium.
     According to P.N. Dilly (1971), colonies of
Rh. compacta are rarely more than 4 mm across, although some colonies may have diameters of about 1 cm.


A. Young coenecium composed of a sicula and two zooidal tubes.
B. Adult coenecium consisting of a sicula and a dozen or so zooidal tubes.
C. Young coenecium built of a sicula and three zooidal tubes.


Mierzejewski, P. and Kulicki, C. 2003. Cortical fibrils and secondary deposits in periderm of the hemichordate Rhabdopleura (Graptolithoidea). - Acta Palaeontologica Polonica 48, 1, 99-111.
edited by
Piotr Mierzejewski, the Count of Calmont and Countess Maja A. Korwin-Kossakowska
since 2002
SEM micrographs from Mierzejewski & Kulicki
Pterobranchs: Rhabdopleuroidea
Portal of Graptolites and Pterobranchs sponsored by M.M. plus M. SZTANDARY