Lyriopsis

Merle, Didier, Pacaud, Jean-Michel, Métais, Grégoire, Bartolini, Annachiara, Lashari, Rafiq A., Brohi, Imdad A., Solangi, Sarfraz H., Marivaux, Laurent & Welcomme, Jean-Loup, 2014, Volutidae (Mollusca: Gastropoda) of the Lakhra Formation (Earliest Eocene, Sindh, Pakistan): systematics, biostratigraphy and paleobiogeography, Zootaxa 3826 (1), pp. 101-138 : 108

Genus Lyriopsis gen. nov.

Type species. Lyria cossmanni Vredenburg, 1923 . Early Eocene from Lakhra Formation (Sindh, Pakistan).

Etymology. Combination of Lyria with the suffix opsis (resembling in appearance). Gender feminine.

Diagnosis. A ventricose “ Lyria ” shape with costae slightly opisthocline, rather flexuous in their posterior part, not corresponding from whorl to whorl. Whorls rather depressed, slightly convex, terraced. Four oblique, strong columellar folds. Protoconch bulbous.

Included species. Lyria cossmanni Vredenburg, 1923 (Lakhra Formation, Sindh Province, Pakistan) and Lyria samanaensis Cox, 1930 (Hangu Formation, Paleocene, Khyber Pakhtunkhwa, Pakistan).

Discussion. Cossmann & Pissarro (1909), Vredenburg (1923) and Cox (1930) attributed these two species to the genus Lyria and compared them to three Eocene species from the Paris Basin: Lyria (Lyria) harpula ( Lamarck, 1803) , L. (L.) subturgidula (d’Orbigny, 1850) (= Voluta turgidula Deshayes, 1835 , not of Brocchi, 1814) and L. (Pseudolyria) coroni (Morlet, 1888) . According to these authors, strong but narrowly rounded costae and a biconic shape are shared with the Eocene Lyria species of the Paris Basin and even with many other Cenozoic species of Lyria . Thus, Lyriopsis is placed in the tribe Lyriini , but four characters distinguish members of Lyria from Lyriopsis : the morphology of the costae, the construction of the columellar folds, the shape of the whorl, and the protoconch. In L. ( Lyria ), the posterior ends of the costae are straight, whereas they are obviously sinuous in Lyriopsis . Regarding the subgenus Pseudolyria Martin, 1931 [type species Pseudolyria ventricola Martin, 1931 by monotypy], the costae are more sinuous than in L. ( Lyria ), but the sinuosity is more anteriorly placed than in Lyriopsis . Moreover, the outer lip of L. ( Pseudolyria ) is crenulated, whereas it is smooth in Lyriopsis . In L. ( Lyria ), the inner lip of most species displays two or three strong basal folds and several weaker folds adapically, whereas only four strong folds have been observed in the species referred to Lyriopsis . The shape of the whorl is rather depressed, slightly convex and terraced in Lyriopsis species, whereas the whorls are strongly convex in most species of Lyria (Lyria) . For these reasons, the placement of Lyriopsis in the Lyriini is provisional and uncertain.