Direct development in the intertidal South American shell-less Onchidella marginata (Couthouy in Gould, 1852) (Gastropoda: Heterobranchia: Onchidiidae)

ABSTRACT

This work shows evidence of complete encapsulated development of Onchidella marginata for the first time in South America. Recent common ancestry was suggested for geographically separated New Zealand sub-Antarctic and South American populations of Onchidella. This could be explained as driven by passive rafting mediated by circumpolar ocean currents. In samples from mussel- and algal-beds in intertidal rocky shores from the southern tip of South America (Tierra del Fuego Island, Argentina) we found both adults and egg masses, and crawling hatchlings were observed.

KEYWORDS:

• Reproduction
• Tierra del Fuego
• rocky shore
• egg mass
• hatchlings
• ecology

Acknowledgements

G. Pastorino (Buenos Aires) kindly provided old literature. Carlos Sanchez contributed to histological procedures. Argentina National Park Administration Agency gave permission [077-DRPA-2017 (renovation)] for sampling in EZ and Provincial Secretary of Environment and Sustainable Development gave permission (Res.SDSyA.978/15) for sampling in PL and CD. We thank an anonymous reviewer of a previous version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We thank CONICET. PhD grant awarded in 2015 to M. C. Dalton, associated with the Scientific and Technological Research subsidy, El Fondo para la Investigación Científica y Tecnológica P. BID PICT 2015 N°2468 awarded to M. G. Palomo are thanked for financial support.