Range extensions for heterobranch sea slugs (formerly opisthobranch) belonging to the families Diaphanidae, Plakobranchidae and Facelinidae on the eastern coast of Australia

Abstract

Southern range extensions of the tropical Australian heterobranch sea slug fauna may be symptomatic of climate change, particularly in south-eastern Australia, a recognized climate change hot-spot. In the Solitary Islands Marine Park, northern New South Wales, the presence of biogeographic mixing means that the southern coastal distribution limit of several tropical marine species and the northern limit of some temperate species overlap. During a year-long series of monthly surveys of sea slug communities on intertidal rocky shores, we observed four species beyond their previously recorded range –Colpodaspis thompsoni, Elysia pusilla, Phidiana bourailliandHerviella claror. The southern migration of species is an anticipated response to warming seas and we note an apparent extension of the southern limit for these taxa.

A Victorian emigrant: first observation and range extension of the nudibranch Tenellia catachroma (Burn, 1963) in Western Australia (Mollusca: Gastropoda)

“…Several recent range extensions have been reported for sea slugs on the east coast and these may be attributed to a combination of increased survey effort and shifts in distribution in response to ocean warming (Nimbs et al 2015;, 2017.…”

Southern range extensions for twelve heterobranch sea slugs (Gastropoda: Heterobranchia) on the eastern coast of Australia

“…For example, the tropical stichodactylid actinian Stichodactyla haddoni (Saville-Kent, 1893), host for three species of tropical commensal shrimps, was recently reported from Port Stephens and Sydney Harbour (Scott et al, 2015). Other documented range extensions on Australia's eastern coast include four heterobranch sea slugs on the mid-north coast of NSW (Nimbs et al 2015) and a number of intertidal mollusc species in eastern Tasmania (Pitt et al, 2010).…”

“…South-eastern Australia is a recognised climate change 'hot-spot' (Hobday & Lough, 2011) where strengthening of the EAC and increasing water temperature may facilitate the arrival and establishment of novel species that may alter species interactions (Underwood & Chapman, 2007). In this area, southward shifts in distribution are anticipated for many marine organisms (Przeslawski et al, 2008), with range extensions already documented for some species of fishes (Figueira & Booth, 2010;Harasti, 2015), scleractinian corals (Baird et al, 2012), sea slugs (Nimbs et al, 2015), and host anemones and their complement of commensal crustaceans (Scott et al, 2015). New species records will come about through greater intensity of observations (sea slugs are inherently rare in time and space -Marshall & Willan, 1999) and as a result of range shifts due to warming conditions.…”

Astonishing diversity revealed: an annotated and illustrated inventory of Nudipleura (Gastropoda: Heterobranchia) from Mozambique

“…Indo-west Pacific. New Caledonia, Papua New Guinea, Australia (Nimbs et al 2015), Philippines, Madagascar , South Africa (Gosliner 1987) and Mozambique.…”