Before the extinction - Permian platyceratid gastropods attached to platycrinitid crinoids and an abnormal four-rayed Platycrinites s.s. wachsmuthi (Wanner) from West Timor

The occurrence of Paleozoic gastropods attached to echinoderms has been recognized for nearly 170 years. Specimens have been illustrated from each of the geologic periods from the Ordovician to Permian. We illustrate two occurrences of Permian platycrinitid camerate crinoids from West Timor, Platycrinites s.s. wachsmuthi (Wanner) and Neoplatycrinus dilatatus Wanner, that have the platyceratid attached on the tegmen on the former and along the radial summit on the latter. Both platyceratids barely cover the anal opening and suppress the development of the arms of at least one ray. The D ray arms are suppressed on Platycrinites s.s. wachsmuthi, whereas the development of the C ray arms and perhaps the most adjacent arms of the D and B rays are suppressed on Neoplatycrinus dilatatus. An additional specimen of Neoplatycrinus major retains the impressed conch outline of a formerly attached platyceratid on the tegmen. This is the first report of a platyceratid/Neoplatycrinus association. The West Timor occurrences are among the youngest known of the platyceratid/platycrinitid association before the End-Permian extinction of the camerates. In addition, an abnormal four-rayed theca of Platycrinites s.s. wachsmuthi is described.