The nassariids from the Gulf of Gabès revisited (Neogastropoda, Nassariidae)

ABSTRACT

Since the latter half of the nineteenth century, marine biologists have recognized that many molluscs living in the Gulf of Gabès, on the southern coast of Tunisia, exhibit a number of morphological characters that set them apart from the ‘typical form or variety’ that occurs in the rest of their Mediterranean distribution area. In the family Nassariidae, local forms (varieties or subspecies) were recognized as early as 1882, but none of these is currently recognized as having taxonomical significance. We have revisited the species-level systematics of the family using an integrative approach, based on morphological, geographic and molecular evidence (COI and 28S). Besides Tritia gibbosula (not sampled by us), we delimitated seven species, three with a broad range: Tritia neritea (probably introduced), T. mutabilis (but with considerable genetic structure between localities), and T. corniculum; and four not previously recognized as valid, and which may be considered Gulf of Gabès endemics: T. lanceolata, T. tenuicosta, T. pallaryana sp. nov. and T. djerbaensis sp. nov. Also, Tritia elongata is recognized as a valid species in the T. corniculum complex, with a distribution outside the Gulf of Gabès. It is remarkable that all have paucispiral protoconchs indicating non-planktotrophic larval development.

http://zoobank.org/urn:lsid:zoobank.org:pub:069F3B3B-66E8-4C07-A974-3023924426EB

RESPONSIBLE EDITOR:

• Rachel Collin

KEYWORDS:

• Nassarius
• Tritia
• endemism
• new species
• integrative taxonomy
• Gulf of Gabès
• cryptic diversity

Acknowledgements

We are grateful to the colleagues who helped us collect in the Gulf of Gabès or sent us specimens from other Mediterranean and Atlantic localities: Manuel Caballer, Serge Gofas, Philippe Maestrati, Javier Martin, Jean Pierre Miquel, Leopoldo Moro, Marco Oliverio, Gianni Spada, Jacques Pelorce and Emmanuel Vassard. Special thanks go to Gianni Spada who did the primary morphospecies segregation and to Hugo Kool who compared our material to his reference collection and offered opinions and suggestions. Yves Samyn (RBINS) facilitated our examination of the material in the Dautzenberg collection. For image acquisition, we acknowledge the support of Sylvain Pont (scanning electron microscope) and Manuel Caballer (E-RECOLTNAT project: ANR-11-INBS-0004) of the MNHN Directorate of Collections. Virginie Héros, Barbara Buge and Philippe Maestrati helped with the curation of vouchers and access to MNHN historical material.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This project was partially supported by the network ‘Bibliothèque du Vivant’ funded by the Centre National de la Recherche Scientifique, MNHN, Institut National de la Recherche Agronomique, Commissariat à l'Energie Atomique and Genoscope, and by the MNHN Action Thématique ‘Barcode’ (PIs: S. Samadi and J.N. Labat).