Eocithara, Fischer, 1883

Merle, Didier & Pacaud, Jean-Michel, 2004, New species of Eocithara Fischer, 1883 (Mollusca, Gastropoda, Harpidae) from the Early Paleogene with phylogenetic analysis of the Harpidae, Geodiversitas 26 (1), pp. 61-87 : 69

Eocithara (s.s.) helenae n. sp. ( Figs 1A ; 4E, F ; 6A )

Eocithara sp. – Merle 1986: 36.

TYPE MATERIAL. — Holotype ( MNHN R 63431, Merle coll.), 3 paratypes ( MNHN R 63436, Merle coll.), 1 paratype ( MNHN R 63800, Merle coll.).

TYPE LOCALITY. — Tuilerie of Gan, Pyrénées-Atlantiques, France, upper Ypresian.

ETYMOLOGY. — For Hélène Merle for her participation to the field research.

MEASUREMENTS. — R 63431 (holotype): height 21 mm, maximal width 11 mm ; R 63436a (paratype): height 19 mm, maximal width 9 mm ; R 63436b (paratype): height 18 mm, maximal width 7.5 mm ; R 63436c (paratype): height 31 mm, maximal width 18 mm (broken) ; R 63800 (paratype): height 18 mm, maximal width 11 mm .

DESCRIPTION OF THE HOLOTYPE

Shell 21 mm in height and 11 mm in width. Protoconch multispiral, conical, of 3.5 smooth whorls. Teleoconch of five slightly convex whorls. Conical spire 19% of total length. Simple, linear suture. Axial sculpture of lamellose, abaxially oriented major varices. Posterior part of major varices adapically projected and moderately covering base of penultimate whorl. Twentyone orthocline major varices on the first whorl and 15 on the last whorl. Five to six lamellose secondary varices between each pair of major varices. Spiral ornamentation of four narrow primary cords (P1 to P4) on first whorl. P1 delineating a small carina on end of first whorl. Secondary cord (s2) appearing on third whorl. Primary and secondary cords indistinguishable on last whorl. Cord spine P1 not present. Axial microsculpture with numerous and fine striae. Aperture oblong of 81% of total length, contract- ed in its abapical angle. Centre of the columella straight, lightly curved over anterior part. Columellar callosity small, labial part well delineated. Pseudoumbilicus very narrow, closed by columellar callosity and delineated by umbilical ridge. Umbilical ridge curved dorsally. Siphonal canal short, curved dorsally. Outer lip thin, but thickened by the last varix, orthocline, with parasigmoid outline.

COMPARISONS

This upper Ypresian species differs from all other European Eocene species by its multispiral protoconch. On the first teleoconch whorl, E. (s.s.) helenae n. sp. also possesses orthocline varices, while they are sinuose in E. (s.s.) mutica , E. (s.s.) elegans and in the Rupelian species E. (s.s.) submutica. E. (s.s.) helenae n. sp. is more nearly similar to the American Priabonian species E. (s.s.) jacksonensis (Harris, 1896) in its multispiral protoconch ( Figs 1B ; 6B ) and in the sculptural features of its first teleoconch whorl (orthocline varices, poorly marked spiral cords). Nevertheless, the spiral sculpture is more developed in E. (s.s.) jacksonensis and no spine in the topological position P1 has been observed in E. (s.s.) helenae n. sp., whereas it commonly occurs in most specimens of E. (s.s.) jacksonensis.

Figures

FIG. 1. — Multispiral (A-D), paucispiral protoconchs (E-G) and teleoconch early sculpture of harpids; A, Eocithara (s.s.) helenae n. sp., holotype MNHN R63431, Tuilerie of Gan, Pyrénées-Atlantiques, France, Ypresian; B, E. (s.s.) jacksonensis (Harris, 1896), MNHN J05528 (Cossmann coll.), Jackson, USA, Priabonian; C, E. (s.s.) submutica (d’Orbigny, 1852), MNHN R63796 (Merle coll.), Gaas, Espibos, Landes, France, Rupelian; D, Harpa doris Röding, 1798, MNHN R11402 (Lecointre coll.), Praia de Castalho, Cape Verde, Recent; E, Eocithara (s.s.) mutica (Lamarck, 1803), MNHN J05527 (Cossmann coll.), Mouchy-le-Châtel, Oise, France, Lutetian; F, E. (s.s.) elegans (Deshayes, 1835), MNHN R11401, Vendrest, Seine-et-Marne, France, Bartonian; G, Austroharpa tenuis (Tate, 1889), MNHN J05731 (Cossmann coll.), Muddy Creek, Australia, Balcombian. Abbreviations: P1-4, abapical primary cords; PS, protoconch scar; s, secondary cords. Scale bars: 1 mm.

FIG. 4. — A, B, Eocithara (s.s.) mutica (Lamarck, 1803), MNHN R63429 (Schtrock coll.), Chaussy, Val d’Oise, France, Lutetian; C, D, E. (s.s.) mutica, MNHN R63430 (Leroy coll.), Saint-Gobain, Aisne, France, lower Ypresian; E, F, E. (s.s.) helenae n. sp., holotype, MNHN R63431 (Merle coll.), Tuilerie of Gan, Pyrénées-Atlantiques, France, upper Ypresian; G, H, Eocithara (s.s.) eucosmia n. sp., holotype, MNHN R63798 (Boucher coll.), Bois-Gouët, Saffré, Loire-Atlantique, France, Bartonian. Scale bars: 10 mm.

FIG. 6. — SEM views of multispiral and paucispiral Eocithara (s.s.); A, Eocithara (s.s.) helenae n. sp., paratype, MNHN R63800 (Merle coll.), Tuilerie of Gan, Pyrénées-Atlantiques, France, upper Ypresian; B, E. (s.s.) jacksonensis (Harris, 1896), MNHN J05528 (Cossmann coll.), Jackson, USA, Priabonian; C, E. (s.s.) submutica (d’Orbigny, 1852), MNHN R63801 (Aucoin coll.), Gaas, Espibos, Landes, France, Rupelian; D, Eocithara (s.s.) mutica (Lamarck, 1803), MNHN J05527 (Cossmann coll.), Mouchy-le-Châtel, Oise, France, Lutetian; E, E. (s.s.) elegans (Deshayes, 1835), MNHN R11401, Vendrest, Seine-et-Marne, France, Bartonian; F, Eocithara (s.s.) eucosmia n. sp., paratype, MNHN R11404 (Ledon coll.), Saint-Aignan-de-Grand-Lieu, Loire-Atlantique, France, Bartonian. The white arrow indicates the protoconch scar. Scale bar: 1 mm.