Calliostomatidae, Colloniidae, Margaritidae, and Solariellidae (Gastropoda: Trochoidea) collected by the Marion Dufresne (MD55) expedition in southeastern Brazil, with description of a new species of Calliostoma

Abstract

The deep-water mollusks collected during the Marion Dufresne (MD55) expedition to the southeastern Brazilian coast in 1987 have been studied in several recent works. The present paper lists and diagnoses 19 species belonging to the vetigastropod families Calliostomatidae, Colloniidae, Margaritidae, and Solariellidae. A new species, Calliostoma valkuri sp. nov., is described. It is mainly characterized by a very short teleoconch I, with limits marked by conspicuous varices and sculpture consisting of 3 spiral threads; sculpture of the teleoconch II consisting of spiral cords with thorn-like projections; and the presence of two strongly marked cords on the median portion of the whorls. Based on the MD55 samples and complementary specimens from other expeditions, the following species have their geographical and/or bathymetrical range extended: Bathymophila euspira, Calliostoma gemmosum, Calliostoma rude, Callogaza watsoni, Gaza compta, Falsimargarita terespira, Homalopoma boffii, Lamellitrochus cancapae comb. nov., Lamellitrochus pourtalesi, Margarites imperialis, and Solariella quinni.

Cerithiidae, Litiopidae, Modulidae and Planaxidae (Gastropoda, Cerithioidea) collected by the Marion Dufresne MD55 expedition in southeastern Brazil

“…This is not unprecedent, since several papers based totally or partially on MD55 material reported the presence of genera and species of gastropods previously unrecorded in the Southwestern Atlantic (e.g., Fernandes et al, 2013;Simone & Cunha, 2014;Salvador et al, 2014;Cavallari et al, 2019;Fernandes & Pimenta, 2020). Significant range expansions of over 1,000 km have also been frequently reported in these studies (e.g., Cavallari et al, 2014;Salvador et al, 2014;Simone & Cunha, 2014;Cavallari et al, 2019). In many cases, the new records leave large occurrence gaps (e.g., some species recorded in the Caribbean and off southeastern Brazil, as in I. oryza).…”

“…The expedition recovered numerous deep-water mollusks from the southeastern Brazilian coast. Most of this material remained unstudied for years, but recent efforts have been steadily changing this scenario, e.g., comprehensive reports on Triphorinae (Fernandes et al, 2013), Naticidae (Simone, 2014), Fissurellidae (Simone & Cunha, 2014), Seguenziidae (Salvador et al, 2014), and Calliostomatidae (Cavallari et al, 2019). The present work focuses on a small assembly of species belonging to the cerithioidean families Cerithiidae, Litiopidae, Modulidae and Planaxidae.…”

Two new species of deep water south Brazilian turriforms (Neogastropoda, Conoidea, Turridae and Cochlespiridae)

“…A more detailed survey of the continental shelf and slope is fundamental, understanding the richness and possible endemicity areas. The malacofauna has been a source of several new recent discoveries (e.g., Simone & Cunha, 2012, 2014Simone, 2014Simone, , 2017Cavallari et al, 2014Cavallari et al, 2019 showing a high diversity and a certain endemicity degree, which undoubtedly can be threatened in case of any petroleum accident.…”