Two new species of Ovassiminea Thiele, 1927 (Truncatelloidea: Assimineidae) from tropical Australia

Abstract

This study reports Ovassiminea Thiele, 1927 (Truncatelloidea: Assimineidae) for the first time in Australia, and two new species, Ovassiminea annulata n. sp., and Ovassiminea miskellyi n. sp., are described. They share a combination of morphological characters similar to the genus type species Ovassiminea dohrniana (Nevill, 1880), such as radular and shell morphology, configuration of the glandular oviduct, and a distinctly undulating anterior vas deferens, the latter a possible autapomorphy for the genus. Maximum Likelihood and Bayesian Inference analyses of a COI mitochondrial fragment (625 bp) suggest evolutionary affinities of the two Australian taxa to the Australian genus Cryptassiminea Fukuda & Ponder, 2005 and Assiminea grayana Fleming, 1828. Of the two new species, O. annulata possesses stronger spiral sculpture, a more pronounced internal protuberance on the operculum, and three pairs of basal cusps on the radula as opposed to two in O. miskellyi. Both species share a long penial papilla that is absent in O. dohrniana. The two species are not sympatric, with O. annulata occurring from the western Gulf of Carpentaria to Darwin, Northern Territory, and with O. miskellyi known from northern Kimberley and the Preston Peninsula, Pilbara, Western Australia.

Ovassiminea annulata http://zoobank.org/urn:lsid:zoobank.org:act:256B4E59-076B-4B5B-A93F-14F0DB3CD6F2

Ovassiminea miskellyi http://zoobank.org/urn:lsid:zoobank.org:act:C997758A-BE45-4B71-BE27-4565D7F391DE

Keywords:

• Ovassiminea
• estuarine
• mangrove
• taxonomy
• Truncatelloidea

Acknowledgements

We wish to thank Winston Ponder for helpful advice, Mandy Reid, Alison Miller and Janet Waterhouse for assistance with collection material and specimen registration, Alison Miller for mounting radulae, and Sue Lindsday for SEM. Furthermore, Ashley Miskelly is thanked for his considerable assistance in the field in northern Australia. Adam Bourke and Kristin N. Metcalfe at EcoScience, Darwin, are acknowledged for collecting assimineid material in NT, and Vince Kessner for collecting in Kimberley, WA. Corey Whisson and Lisa Kirkendale (WAM), and Richard Willan (NTM), are thanked for their assistance with registration of type material. Francesco Criscione is acknowledged for providing a name for one of the species, and we thank the Australian Biological Resources Study (ABRS) for a postdoctoral grant awarded to A. Hallan. Finally, Bruce Marshall, Martin Haase and an anonymous reviewer are thanked for providing feedback which has improved this study.

Disclosure statement

No potential conflict of interest was reported by the authors.