Redescription and three-dimensional reconstruction of the limnic acochlidian gastropod Strubellia paradoxa (Strubell, 1892) (Gastropoda: Euthyneura) from Ambon, Indonesia

Abstract

This study is the first to examine the entire microanatomy of a representative of the limnic family Acochlidiidae s.l., belonging to the otherwise marine mesopsammic Acochlidia. A paratype of Strubellia paradoxa (Strubell, 1892) was reconstructed three-dimensionally from serial semi-thin sections using the software Amira; additional material recently collected close to the type locality on Ambon Island, Indonesia was examined by scanning electron microscopy. Results are critically compared with the original description by Küthe of 1935. The genital system of S. paradoxa is monaulic, with two allosperm receptacles in the male phase, suggesting that the species is a sequential, protandric hermaphrodite rather than gonochoric; an open seminal groove connects to a complex cephalic copulatory apparatus. The two-chambered heart with conspicuous epicardium, the elongated kidney and the looped nephroduct are interpreted as possible adaptations to the freshwater habitat. Differences from S. “paradoxa” sensu Wawra 1974 and 1988 from the Solomon Islands are discussed.

Keywords:

• Mollusca
• Heterobranchia
• Opisthobranchia
• histology
• microanatomy

Acknowledgements

Katharina Jörger is thanked for her help during the entire project and with the SEM, and Tobias Lehmann is thanked for embedding the specimen recollected from Ambon (both ZSM). Jürgen Kriwet (Stuttgart) is thanked for his help during the field trip to Ambon in 2008. Rick Hochberg (University of Massachusetts) and an anonymous reviewer are thanked for their helpful comments on the manuscript. This study was financed by a grant of the German Research Foundation (DFG SCHR 667/4-3 to MS). Three-dimensional reconstruction was supported by the GeoBioCenter/LMU München.