Two new species of the tropical facelinid nudibranch Moridilla Bergh, 1888 (Heterobranchia: Aeolidida) from Australasia

WA Museum Records and Supplements | Updated 6 years ago

ABSTRACT – The Indo-Pacific aeolid nudibranch Moridilla brockii Bergh, 1888 comprises a species complex. Here we describe two morphs from the complex as new species. Using morphological comparisons, we show the new species to be closely related but distinct from each other and from M. brockii. Distributed across north-western Australia, M. fifo sp. nov. is known from Exmouth, Western Australia to the Wessel Islands, Northern Territory, whereas M. hermanita sp. nov. is known only from Madang, Papua New Guinea. Differences between the two species include colouration, the size of the receptaculum seminis and some distinction in the jaws. Unravelling the entire complex will take much wider geographic sampling, and will require recollection from the type locality of M. brockii. This group is yet another example of a purportedly widespread aeolid species comprising a complex of species.