Table 1. Collection information and GenBank accession numbers for the samples analysed herein.

Species	Locality	Coordinates	Year	N	GenBank accession nos.
Aylacostoma stigmaticum	Isla Ibicuy, PY*	27°17′56.76′′S; 56°3′28.44′′W**	1934	1	KU168372
Aylacostoma brunneum	Ita Cuá, PY	27°24′42.13′′S; 55°48′45.69′′W	2007	1	KU168374
	Río Beach, PY*	27°24′29.83′′S; 55°49′32.94′′W	2007	2	KU168373, KU168375
Aylacostoma chloroticum	Candelaria, AR	27°26′50.96′′S; 55°45′0.84′′W	2008	4	KU168376 –KU168379
			2011	2	KU168380, KU168381
	Río Beach, PY	27°24′29.83′′S; 55°49′32.94′′W	2007	1	KU168382
Doryssa sp.***	Venezuela	–	2010	1	KU168383
Pachychilus laevissimus***	Venezuela	–	2010	1	KU168384
Pachychilus nigratus***	Cuba	–	1997	1	KU168385

AR, Argentina; PY, Paraguay; N, number of specimens analysed.

*Type locality.

**The coordinates are approximate; only the locality name was reported in the original description and the precise location is uncertain.

***Outgroup species.