Pneumoderma heronensis nov. sp.: A new Pteropod (Opisthobranchia; Gymnosomata) from Australian waters

In April 1987, seven specimens of a new species of the gymnosomatous pteropod, Pneumoderma heronensis, were collected from surface waters between Heron and Wistari Reefs, southern Great Barrier Reef, Australia (23° 27’S 151° 55’E). Additional specimens were identified from CSIRO plankton collections from the Northwest Shelf, Western Australia (19° 25’S 119° 30’E). This new species is described and illustrated from living specimens. Uniquely, P. heronensis possess 12 lateral buccal arm suckers, arranged alternately in two rows. Morphological comparisons are made with closely related species; P. mediterraneum (Van Beneden, 1838), P. atlanticum atlanticum (Oken, 1815) forma eurycotylum (Meisenheimer, 1905) and P. degraafíi Spoel & Pafort-van Iersel, 1982.