The Aglajidae is a family of about 100 species that are distributed worldwide across tropical and temperate latitudes, and are particularly common in the tropical Indo-West Pacific. In Australia, large and small species are common all around the coast, from the intertidal down to over 200 m deep, but they are most common in the tropics, living in or on shallow sand. Reaching a size up to about 60 mm, some species have brightly coloured animals and so are obvious on reefs and the shore.
In the Aglajidae the shell is usually internal, reduced, and usually not calcified, but in the genera Chelidonura and Noalda there is a solid, white shell. Aglajids are active predators feeding on animals including other sea slugs, and polychaete and nemertean worms, which they ingest whole by means of a strongly muscular pharynx.
Zamora-Silva, A. & Malaquias, M.A.E. 2017. Molecular phylogeny of the Aglajidae head-shield slugs (Heterobranchia: Cephalaspidea): new evolutionary lineages revealed and proposal of a new classification. Zoological Journal of the Linnean Society for 2017: 1-51.
There are at least 15 species of this family recorded from NSW of which several are reasonably common at low tide and in the shallow subtidal. Only one species is detailed here, All have internal shells. Using the most recent nomenclature (Zamora-Silva & Malaquias 2017), they are as follows:
Biuve fulvipunctata (Baba, 1938)
Chelidonura electra Rudman, 1970
Chelidonura hirundinina (Quoy & Gaimard, 1833)
Chelidonura varians Eliot, 1903
Mariaglaja inornata (Baba, 1949)
Mariaglaja sandrana (Rudman, 1973)
Melanochlamys queritor (Burn, 1957)
Noalda exigua (Hedley, 1912)
Philinopsis speciosa Pease, 1860
Philinopsis taronga (Allan, 1933)
Spinoaglaja orientalis (Baba, 1949)
Spinophallus falciphallus Gosliner, 2011
Tubuliphilinopsis lineolata (H. & A. Adams, 1854)
Tubuliphilinopsis pilsbryi (Eliot, 1900)
Tubuliphilinopsis reticulata (Eliot, 1903)
Some of these species are illustrated on the Sea Slug Forum.
Aglajids are recognised by their cylindrical bodies, and the visceral shield being extended into lobes posteriorly like the tail of a swallow.
Copyright Des Beechey 2018