Studies in Canarium urceus (Linné, 1758) Part 4: Canarium (Canarium) orrae (Abbott, 1960) (Gastropoda: Neostromboidae: Strombidae) and a new species from the Northern Territory, Australia

This part of the Canarium (Canarium) urceus (Linné, 1758) after Abbott (1960) revision examines the Australian species of that complex. Currently, there is one recognised species, Canarium (Canarium) orrae (Abbott, 1960), which is divided herein into two species, with the description of Canarium (Canarium) darwinense n. sp. from the Van Diemen Gulf and Darwin surrounds. The C. (C.) darwinense is distinguished from C. (C.) orrae in morphological form. The southern range of C. (C.) orrae is extended to Monkey Mia, Shark Bay. Examples of C. (C.) orrae were also noted from the North Coast of Sumbawa, Indonesia, and Port Moresby, Papua New Guinea. While there is a geographic break in the distribution of C. (C.) orrae creating two populations, Western Australian and Gulf of Carpentaria, populations from these two ranges could not be distinguished using morphology. Future research will likely show genetic differences as a consequence of drift caused by isolation, thus leading to the potential recognition of two cryptic subspecies.