Over its quite considerable range, this species exists as three distinct ecomorphs, the typical one on the cold Atlantic coast, form insignis on the warmer south and east coasts and form kraussi in the more sheltered habitats in False Bay. Genetically they cluster as an unresolved clade exhibiting little genetic differentiation

As Phasaniella kraussi:
It is smaller than P. capensis, the only species it can be compared with, is different in form, and the style of coloration is also different. The general outline is more ovate, the spire shorter, the body-whorl larger in proportion to the rest of the shell, and the aperture is also larger and almost patulate. It is difficult to describe the colour. It consists of reddish-brown and creamy or white undulating lines, the reddish-brown colour usually predominating. The white markings are most conspicuous below the suture on the body-whorl, and they are very frequently bordered on their anterior margin with dark brown, in some specimens in the form of spots. The apex of the spire is pale and pellucid, and sometimes the penultimate whorl is almost without colour - markings, being uniformly corneous. In a few specimens the reddish-brown colour is replaced by a dark purple-brown tint. The dimensions given are those of an average-size example. The largest specimen observed is 6 mm. in length.

T. bicarinata occurs on the Atlantic Cape coast, from Kommetjie to Namibia (Luderitz); On intertidal and near-shore reefs to 30 m.