Houtman Abrolhos
The Houtman Abrolhos is unusual in having a luxuriant and diverse living coral reef at such a high latitude. 194 species in 50 genera have been recorded there, all but two of which are tropical. This is a surprisingly high coral diversity, considering the high latitude of the reef, and the relatively low diversity of other biota. For a full list, see list of corals of the Houtman Abrolhos.
Abbottella
A third complex consists of species with rather large, openly coiled to nearly planispiral shells with pronounced prickly sculpture and widely expanded outer lips; the shells are often strongly patterned. The group contains "Abbottella haitensis", and "Abbottella moreletianus". Bartsch (1946) broke "Abbottella moreletianus" into five subspecies. Zoogeographically, this group presents a problem: the two species occur at opposite ends of the island (Thomazeau, Haiti and the Samaná Peninsula and environs). This group will be addressed in a future study.