TYPE SPECIES: Rissoa coriacea MANZONI, 1868, recent. Madeira.
DIAGNOSIS: Vanikorids with a tall, rissoiform shell sculptured by low sigmoid lamellae, narrow or no umbilicus and with a simple foot with epipodial folds but without posterior sucker.
REMARKS: VAN AARTSEN (1984) pointed out that the name Salassia DE FOLIN, 1870 was based on a pyramidellid type species, S. carinata DE FOLIN, 1873, from W Central America. The name had previously been used for certain NE Atlantic species resembling and with some doubts referred to the Rissoidae (MONTEROSATO 1889), viz.:
Salassia dagueneti DE FOLIN, 1873 (N Spain).
Rissoa coriacea MANZONI, 1868 (Madeira, ex coll MACANDREW, therefore probably dredged)
Rissoa tenuisculpta WATSON, 1873 (Madeira, 40-90 m).
The specimens on which these three names are based are quite similar. We have examined DE FOLIN'S and WATSON'S types, specimens identified as coriacea by WATSON and other material from the Bay of Biscay. S of Spain and from the Alboran Sea in depths between 50 and 1200 m, but have not been able to decide how many species that are involved. Ex¬amination of preserved specimens revealed soft parts very similar to those of Megalomphalus azomts, a foot without a sucker, large, fleshy epipodial folds and a radula of vanikorid type. This supports PONDERS (1985:105) assumption that tenuisculpta WATSON and coriacea MANZONI might be related to the Vanikoridae, and we decided to introduce a new genus for these species.
We agree with PONDER (1985:105) that Rissoa macrostoma THIELE, 1925, from the Agulhas Bank belongs here. Also Cingula sandersoni VERRILL, 1884, belongs to Talassia, judging from shell characters (fig. 48). It was described from off Cape Halteras (NE USA) in 250 m depth and only empty shells are known. WAREN (1974:134) suggested that it belongs to Rissoellidae or Aclididae, which is obviously wrong.
Two genera, presently placed in Epitoniidae (Wenz 1940) deserve com-parison with Talassia: Berthais MELVILL, 1904. type species Scala intertexta MELVILL & STANDEN, 1903 (fig. 49) from the Gulf of Oman in 280 m and Constantia A. ADAMS, 1&60, type species C. elegans A. ADAMS, 1860, from the Strait of Korea, depth 113 m.
Berthais and Constantia differ from Talassia in having a strong, reticulated sculpture with straight axial ribs more similar to those of Couthouyia.
Both genera may turn out to belong to Vanikoridae when the family is better known, or the soft parts are known. Berthais may then turn out to be a junior synonym oi Cytnenorhytis COSSMAN, 1888 (type species Melania fragilis LAMARCK, 1804, Eocene, Paris Basin; for illustration see GOUGEROT & LE RENARD, 1981).

One new species of the genus Talassia is described from the Gulf of Mexico and three are described from western Africa. All American and western African species show a predominantly smooth protoconch. Conversely, the three hitherto known species from the NE Atlantic and western Mediterranean Sea all show protoconchs with spiral sculptures. The two American species have spiral cordlets on the teleoconchs; the NE Atlantic species lack distinct spiral features.

Talassia tenuisculpta, T dagueneti, T. sandersoni, T mexicana sp. nov., T. laevapex sp. nov. and T. flexisculpta sp. nov. have been found in association with DWC habitats. The food source of these species must be present in these habitats. A link between Talassia rugosa sp. nov. and coral habitats needs to be confirmed.

Talassia laevapex sp. nov., T flexisculpta sp. nov. and T. rugosa sp. nov. have been found in upper bathyal oxygen minimum zones (OMZ) off western Africa (Westphal 2007; Westphal et ah 2014; Hebbeln et al 2016, 2020; Ramos et al 2017; Wienberg et al 2018). Off Cape Blanc (NW Africa), the southward flowing Canary Current collides with the northward flowing Mauritanian current thereby forming the SW flowing Northern Equatorial Current (NEC). The bathyal water mass south of the NEC has a dissolved oxygen concentration of less than 1.5 ml/1 (Wienberg et al. 2018). Higher oxygen levels are found in the water mass to the north of the NEC (Wienberg et al. 2018). Hence, it is likely that this hydro-oceanographic separation causes a distinct development of NE Atlantic and West African bathyal species.

The reference collection at SaM contains shells of Talassia dagueneti from the Porcupine Basin. This submarine structure is the northern extent of its distribution range. Talassia dagueneti shows significant variability in outline and sculpture over its distribution area (Waren & Bouchet 1988; Bouchet & Waren 1993).

Similarly, many shells of Talassia tenuisculpta have been found on seamounts south of the Azores. This area currently is the western extent of its distribution area. The species has relatively little variability; it appears to have a more southern range when compared to T. dagueneti, including the Lusitanian Seamounts and island slopes off Madeira and the Canary Islands. The syntype figured by Waren & Bouchet (1988: fig. 44) is a slender subadult specimen. We consider the species distinct from T dagueneti based on the sculpture of the teleoconch.