New record of the nudibranch Polycera hedgpethi Er. Marcus, 1964, in South Australia, with a discussion on its occurrence in Australia

WA Museum Records and Supplements | Updated 8 years ago

INTRODUCTION – Polycera hedgpethi was first described from California (Marcus 1964), where it occurs along the entire Californian coastline (Gosliner 1982). Some authors (Gosliner 1982; McDonald 1983) believe it to also occur in the Gulf of California as P. gnupa Ev. Marcus and Er. Marcus, 1967, but this remains contested (Miller 2001). After its description, P. hedgpethi was quickly recorded from a number of other localities across the globe, often appearing in ports. Its widespread distribution has been interpreted as indicating an invasive species, thought to have spread via fouling on ships (Rudman 1999). This scenario was already suggested for Thecacera pennigera by Willan (1976). To date, the Australian National Marine Pest Information System (NIMPIS) suggests that P. hedgpethi is native to California, cryptogenic in the Caribbean, and introduced to South Africa, south West Africa, the Mediterranean, Australia and New Zealand (NIMPIS 2002 and references therein). It is also recently reported from Japan (Keiu 2000) and the Atlantic coast of the Iberian Peninsula (Caballer and Ortea 2002). Although California is assumed to be the natural range of P. hedgpethi, multiple specimens were known from New Zealand prior to the original species description (Miller 2001).