Lyriopsis cossmanni ( Vredenburg, 1923 )

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 : 110

Lyriopsis cossmanni ( Vredenburg, 1923) comb. nov.

( Fig. 4 I–K)

Lyria cossmanni Vredenburg, 1923: 264 (new name for Lyria sihesurensis sensu Cossmann & Pissarro, 1909 , pl. 2, fig. 26 and pl. 3, figs 25–26, incorrect identification as Voluta sihesurensis d’Archiac & Haime, 1853 ).

Lyria sihesurensis (non Voluta sihesurensis d’Archiac & Haime, 1853 ). Cossmann & Pissarro, 1909: 29, pl. 2, fig. 26, 31 and pl. 3, figs 25–26 [new combination].

Lyria feddeni Vredenburg, 1923: 265 (new name for Lyria sihesurensis sensu Cossmann & Pissarro, 1909 , pl. 2, fig. 31, incorrect identification as Voluta sihesurensis d’Archiac & Haime, 1853 ); Cotter in Vredenburg 1928: 37.

Lyria cossmanni . Cotter in Vredenburg 1928: 37.

Description. Shell biconic, H 30–32, D 16–20 mm. Protoconch smooth, rounded, bulbous, of 2¼ whorls, strongly differentiated from teleoconch. Teleoconch of 4 to 4 ¼ whorls. Spire low, occupying 23% of total shell height. Spiral whorls rather depressed, weakly convex, terraced. Last whorl ventricose. Suture slightly channelled. Axial sculpture of strong but narrowly rounded costae, not corresponding from whorl to whorl. Costae slightly opisthocline, extending from suture to suture on spire, posterior part rather flexuous, extending to base. First whorl: 18 costae, spire: 10–12 costae, last whorl: 9–10 costae. Spiral sculpture of ca. 30 fine threads present only from base to anterior half of last whorl. No spiral sculpture on spire. Aperture narrowly ovate, occupying 60% of total height, 28% of diameter. Posterior notch shallow. Outer lip thickened externally. Inner lip almost straight anteriorly, slightly curved posteriorly. Parietal callus weakly developed. Four strong columellar folds. Base of siphonal canal not preserved.

Material. 2 spm (stn 4: CPAG.RAN. I.6–7, cast MNHN.F. A50344 –45).

Comments. According to Vredenburg (1923), Cossmann & Pissarro (1909) made a mistake in identifying the Ranikot material as Lyria sihesurensis , which represents another species from the Middle Eocene of the Salt Range ( Pakistan). From the monograph of Cossmann & Pissarro (1909), Vredenburg (1923) distinguished two species: Lyria cossmanni (in reference to Lyria sihesurensis sensu Cossmann & Pissarro, 1909 , pl. 2, fig. 26 and pl. 3, figs 25–26) and L. feddeni (in reference to Lyria sihesurensis sensu Cossmann & Pissarro, 1909 pl. 2, 31 only). The figured material of L. cossmanni corresponds to three specimens from Jhirak (two well-preserved juveniles and a less well-preserved adult). The specimen illustrated on plate 3, fig. 26 is a well-preserved juvenile and is designated here as the lectotype of L. cossmanni . The material collected in the Lakhra Dome is similar to the specimens of L. cossmanni from Jhirak and shares fine threads present only from the base to anterior part of the last whorl and opisthocline costae flexuous over the posterior part of the whorls. The only illustrated specimen of L. feddeni is designated here as the lectotype of the species. Unfortunately, it is poorly preserved and it is difficult to establish differences between L. cossmanni and L. feddeni , although they were published in the same work (respectively Vredenburg 1923, pp. 264 and 265). In respect to article 24.2.2 of the ICZN (Determination of precedence of names or acts by the First Reviser) we act as first revisers and give precedence to the name Lyria cossmanni by those who consider L. cossmanni and L. feddeni to be conspecific; thus the valid name for the species is Lyriopsis cossmanni ( Vredenburg, 1923) . L. cossmanni can be compared to L. samanaensis Cox, 1930 from the Paleocene ( Köthe 1988; Wardlaw et al. 2007; Afzal et al. 2009) of the Hangu Formation (Samana Range, North Pakistan). Cox (1930) compared L. samanensis to L. feddeni , but as seen above, the illustrated specimen of L. feddeni does not allow accurate identification. Lakhra specimens are very similar to the holotype of L. samanaensis . They share the same number of costae on the spire and on the last whorl, a flexuous morphology of these costae, spiral threads on the base of the last whorl, four oblique and strong columellar folds on the inner lip, and a pyriform outline. These numerous similarities suggest strongly that Lyriopsis cossmanni and Lyriopsis samanaensis belong to the same species. However, the protoconch Lyriopsis samanaensis is missing and this character is needed before we can regard L. samanensis as a junior synonym of L. cossmanni . Kachhara et al. (2011) reported the occurrence of L. feddeni in the Paleocene from Southwestern Kachchh, Gujarat ( India), but this identification is based only on an internal cast lacking specific characters.

Stratigraphic range. Lakhra Formation: Jhirak ( Cossmann & Pissarro 1909; Vredenburg 1923) and Lakhra Dome (this paper).

Figures

FIGURE 4. A. Lyria sp., CPAG. RAN. I. 1, stn 5; B – H. Mitreola brohii sp. nov., B – C (holotype, CPAG. RAN. I. 2, ventral (B) and dorsal (C) views, stn 4), D (paratype 1, CPAG RAN. I. 3, ventral view, stn 4), E – F (paratype 2, CPAG. RAN. I. 4, ventral (E) and dorsal (F) views, stn 4), G – H (paratype 3, CPAG. RAN. I. 5, juvenile, ventral view (G) and enlarged view of the spire (H), stn 4); I – K. Lyriopsis cossmanni (Vredenburg, 1923), I – J (CPAG. RAN. I. 6, ventral view (I) and enlarged view of the spire (J), stn 4), K (CPAG. RAN. I. 7, ventral view, stn 4); L. Lyrischapa haimei (d’Archiac & Haime, 1853), CPAG. RAN. I. 8, ventral view, stn 6; M – N. Lyrischapa sismondai (d’Archiac & Haime, 1853), M (CPAG. RAN. I. 10, ventral view, stn 6), N (CPAG. RAN. I. 9, dorsal view, stn 3). Scale bars: B – G, I, K – N = 10 mm; A, H, J = 5 mm.