Genus Pusionella Gray, 1847

Type species. Buccinum nifat Bruguière, 1789, original designation by Gray (1847: 137). Present-day, western Africa.

Note. When establishing Pusionella, Gray (1847: 137) listed “ Terebra (Nifat) Adans. 1757. Fusus, sp. Lam. Mur. Pusio, Born. ” Petit (2012: 137) referred to " Mur. Pusio, Born " as first type species designation and concluded that this designation was based on a misidentified type species, because Born (1780: 316) attributed Murex pusio to Linnaeus [= Pisania pusio (Linnaeus, 1758); family Buccinidae]. On page 129, however, Gray (1847) states: “ The method I have followed is to observe the first name given to the genus and the type on which it was founded ”. Therefore, Buccinum nifat Bruguière, 1789 was originally designated as type species of Pusionella and the status of Murex pusio Born is not relevant here. The specimen illustrated by Adanson (1757), which is the type specimen of Bruguière (1789), was identified and illustrated by Fischer-Piette (1942: 165, pl. 2 fig. 10).

Diagnosis. ‘Shell rather large, 35–40 mm, subfusiform, with a moderately tall spire of rather flat-sided whorls, a long narrow body-whorl, considerably excavated over the neck, and produced below into a moderately long slightly flexed and deeply notched anterior canal, with a ridge-margined fasciole. Aperture narrowly ovate-pyriform; outer lip thin edged, sinuous with a broad subsutural very slight sinus, a very widely open V, its apex above the greatest peripheral convexity. Protoconch conical, apparently smooth and several whorls. Early post-embryonic whorls closely axially costate’ (Powell 1966: 67).

Discussion. Pusionella species are easily distinguished from Clavatula and Perrona by their very shallow anal sinus (Figs 10F–G). Like the type species P. nifat, P. palatina has a row of large opisthocline suprasutural beads on early teleoconch whorls, and we assume that this sculpture is characteristic for the genus.

Paleoecology. Extant Pusionella species occur in inner neritic environments, e.g., Boyer & Ryall (2006) report Pusionella ghanaensis from 18 to 34 m water depth.

Distribution and stratigraphy. Pusionella is a poorly diverse genus with ten species restricted to the tropical Eastern Atlantic off western Africa (Tucker 2004; MolluscaBase 2022). The oldest record listed by Tucker (2004) is Pusionella prima Ryckholt, 1861, from the Cretaceous of Belgium. Based on the illustration in Ryckholt (1861: pl. 30, figs. 22, 23), this species is unrelated to Pusionella. Pusionella procera Hölzl, 1962 from the Egerian (= Chattian) of Germany (Hölzl 1962: 189, pl. 10, fig. 8) is based in poorly preserved internal casts and placement in Pusionella is not supported by conchological features. A reliable fossil record starts during the early Miocene, when Pusionella was well established along the European coasts with Pusionella borealis Kautsky, 1925 in the North Sea Basin, P. pseudofusus (Des Moulins, 1842) in the northeastern Atlantic and P. tauronifat Sacco, 1891 and P. pedemontana Sacco, 1891 in the Proto-Mediterranean Sea (Sacco 1891; Peyrot 1931; Glibert 1954) [note that Pusionella saucatensis Mayer listed by Kautsky (1925: 151) is a nomen nudum]. During the Miocene Climatic Optimum, the genus reached the Central Paratethys Sea and was represented by P. palatina and P. hofmanni nov. sp. The genus vanished from the Paratethys Sea after the Langhian, but persisted into the Serravallian in the northeastern Atlantic (Peyrot 1931; Glibert 1954). We are not aware of any fossils from the African coasts. Pusionella did not re-enter the Mediterranean Sea during the Pliocene.