Angulatella Nützel and Hausmann

Hausmann, Imelda M., Nützel, Alexander, Roden, Vanessa Julie & Reich, Mike, 2021, Palaeoecology of tropical marine invertebrate assemblages from the Late Triassic of Misurina, Dolomites, Italy, Acta Palaeontologica Polonica 66 (1), pp. 143-192 : 159

Genus Angulatella Nützel and Hausmann nov.

ZooBank LSID: urn:lsid:zoobank.org:act:A90DB9CA-6986-4819-BABB-ECBE164CFDA2

Type species: Angulatella bizzarinii Nützel and Hausmann sp. nov., see below.

Species included: Type species only.

Diagnosis.—High-spired shell, spiral keels on teleoconch; upper keel angulates whorl profile in early teleoconch whorls, with a steep ramp between adapical suture and keel; whorl profile concave, parallel to shell axis between upper and lower keels; later whorl more or less convex with weaker angulations; base convex, anomphalous; protoconch orthostrophic; larval whorls ornamented with two strong spiral keels; third spiral keel present on third protoconch whorls; spiral keels angulate larval whorls; spiral keels ornamented with minute tubercles; protoconch ends abruptly at sinusigera; sinus strengthened with a varix.

Remarks.—The carinate, small larval shell of Angulatella closely resembles larval shells of many Recent and fossil Cerithioidea. The teleoconch resembles that of some Mathildoidea. However, Mathildoidea have a heterostrophic protoconch. The finding of Angulatella is further evidence for an early radiation of Cerithioidea. The small bicarinated larval shell resembles that of Permocerithium Nützel, 2012 ( Nützel and Nakazawa 2012) from the Middle Permian of Japan. However, the teleoconch of this genus is not angulated. The Triassic Camposcala has the same type of larval shell but differs from Angulatella in having a strong cancellate teleoconch ornament. Small bicarinated larval shells of the same type have been reported from numerous Mesozoic Cerithoidea (e.g., Bandel 1992; Schröder 1995; Kaim 2004; Guzhov 2004).

Stratigraphic and geographic range.—Only known from the Carnian, Upper Triassic; northern Italy (Cassian Formation).