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Burchard's Dog Whelk

Tritia burchardi

This snail can be found in estuaries and lagoons intertidally. It is relatively bulbous and is distinctly ribbed. On the body whorl, the ribbing fades and the dorsal surface is smooth and unsculptured. The shell is a light green to brown, with darker brown colouration between the ribs. This species is native to Australia, but has established in some areas of New Zealand.

Scintillula solida

This tiny bivalve is a brilliant white in colour and globular. It has a smooth and shiny appearance with a very fine concentric sculpture. It can be difficult to distinguish from other galeommatid bivalves, including Lasaea australis, but its lack of purple pigmentation and less obvious sculpture can differentiate it from that species.

Ascidiella aspersa
directions_boat Introduced species

This introduced solitary ascidian is native to Europe, but now spread globally due to shipping. Its test is a cloudy white or grey, flecked with red and covered in white papillae. The relatively short siphons are lobed and can have red stripes inside. This species resembles many others in the Ascidia genus, but in those species there are usually no papillae.

Diala suturalis

This tiny snail can often be found in very shallow tidepools, where it feeds on filamentous algae. It has a moderately tall spire, with slightly convex whorls. The pattern is somewhat variable, but consists of spiral brown bands of varying width, the lines sometimes broken. The aperture is thin and straight-edged, unbroken by a siphonal canal. This species is difficult to differentiate from other small snails and expert examination can be helpful.

Stereotheca elongata

This pinnate (feather-shaped) hydroid colony can be found on seagrasses and algae, often Amphibolis stems. The colonies themselves can be encrusted by coralline red algae and other epiphytes. The terminal branches of the colony emerge from the zigzag main branches in an alternating arrangement on each side of the branch and the polyps emerge directly from these terminal branches, protected by their cup-shaped hydrothecae. This species can be difficult to identify, but has distinctive jagged-edged hydrothecae along with the other characteristics discussed here.

Leptochiton liratus

This uncommon chiton is a uniform light brown in colour. It has thin longitudinal grooves on both the pleural and lateral areas, although they are thickened or warped in places. It has a girdle of tiny scales, with a fringe of hair-like spicules. This species can be distinguished from other similar species by its uniformly thin sculpturing.

Goniocidaris tubaria

This small pencil urchin is found in various shades of red and white. It has thick primary spines surrounded at the base by a ring of small flattened secondary spines. The primary spines themselves are covered in small spinelets down their entire length, although they are occasionally eroded smooth, or encrusted with epiphytes. Although these spinelets are a giveaway when identifying this species, when they are not visible it can be difficult to distinguish from Goniocidaris impressa. In these cases, the easiest way to differentiate the two species is by the rings of secondary spines, which are flattened in G. tubaria instead of rounded and club-shaped.

Gigartina brachiata

This common red algae forms tangled mats or clumps on rocky reef and coast. It is red in colour, fading to a light cream. This colour transition can often be seen as a red plant with cream blotches or vice versa. The branching thallus is about 1mm thick and each branch terminates in a point. This algae is ubiquitous on many exposed reefs, and is usually easily identified.

Magpie Morwong

Goniistius gibbosus

Previously found only in Western Australia, this whitish morwing species is known from only a handful of photographs in SA, all taken at Port Noarlunga since 2023. It has dark diagonal banding on the front part of the body, to the pelvic fins, and another dark stripe running under the dorsal fin to the tail. The tail and fins are a pale yellow. Although their ranges do not currently overlap, this species is almost identical to the Crested Morwong (Goniistius vestitus), found on the east coast of Australia, and can be differentiated by minor variations in the pattern.

Synalpheus tumidomanus

This snapping shrimp is associated with sponges, but can also be found amongst algae and corals. It is a transparent blue grey in colour, with small red spots on the carapace. The three prongs on its rostrum are almost equal in length. This species can be identified by its colouration and the presence of red spots.