Retusa obtusa
Authors/Creators
- 1. Université de Rennes, Campus de Beaulieu, 263 avenue Général Leclerc 35042 Rennes (France) bouchardblanche @ gmail. com (corresponding author)
- 2. Naturalis Biodiversity Center, P. O. Box 9517, 2300 RA Leiden (The Netherlands) and Department of Earth Sciences, Utrecht University, Princetonlaan 8 a, 3584 CB Utrecht (The Netherlands)
- 3. Naturalis Biodiversity Center, P. O. Box 9517, 2300 RA Leiden (The Netherlands)
Description
Retusa obtusa (Montagu, 1803)
(Fig. 13D 1-D 3)
Bulla obtusa Montagu, 1803: 223.
Utriculus obtusus – Harmer 1923: 797, pl. 63, fig. 4.
Retusa alba – Van Regteren Altena et al. 1965: 26, pl. 21, fig. 205. — Ceulemans et al. 2018: 122, pl. 7, fig. 9.
For more, see synonymy list in Ceulemans et al. (2018).
MATERIAL AND DIMENSIONS. — Maximum height 1.7 mm, width 0.8 mm. — RGM.1365120 (20), leg. AWJ; RGM.1365121 (1), leg. AWJ; RGM.1365017 (3), leg. ACJ.
SPECIES CHARACTERISATION. — Shell small, subcylindrical with low spire. Two to three teleoconch whorls separated by deeply impressed suture. Surface smooth. Aperture elongate expanded abapically.
DISTRIBUTION. — Lower Pliocene: NSB, England (Harmer 1923); Atlantic, NW France (Ceulemans et al. 2018). — Upper Pliocene: NSB, Red Crag, England (Wood 1848). — Upper Pliocene-Pleistocene: NSB, Holland (Van Regetren Altena et al. 1955). — Lower Pleistocene: Atlantic, Selsoif, NW France (this paper). — Middle Pleistocene: Atlantic, Irish Sea (Harmer 1923). Today, this species occurs in the Atlantic from Greenland, Iceland to Scandinavia, Nova Scotia to Aleutian Islands, British Isles (Thompson 1988).
REMARKS
Retusa obtusa is variable in shape and size with a more or less elevated apex (Ceulemans et al. 2018). As noted by those authors, this species is rarely reported in the fossil literature. It is predominantly a cooler water species with the most southern record being that of the Lower Pliocene of Le Pigeon Blanc (NW France).
Notes
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Linked records
Additional details
Identifiers
Biodiversity
- Collection code
- RGM
- Material sample ID
- RGM.1365017 , RGM.1365120 , RGM.1365121
- Scientific name authorship
- Montagu
- Kingdom
- Animalia
- Phylum
- Mollusca
- Order
- Cephalaspidea
- Family
- Retusidae
- Genus
- Retusa
- Species
- obtusa
- Taxon rank
- species
- Taxonomic concept label
- Retusa obtusa (Montagu, 1803) sec. Bouchard, Wesselingh, Pouwer & Landau, 2025
References
- MONTAGU G. 1803. - Testacea Britannica or Natural History of British Shells, Marine, Land, and Fresh-Water, Including the most Minute: Systematically Arranged and Embellished with Figures. J. White, London, Vol. 1, xxxvii + 291 p.; Vol. 2, p. 293-606, pl. 1 - 16.
- REGTEREN ALTENA C. O. VAN, BLOKLANDER A. & POUDEROYEN L. P. 1965. - De fossiele schelpen van de Nederlandse stranden en zeegaten I, 2 de druk. Nederlandse Malacologische Vereniging, Leiden, 358 p.
- CEULEMANS L., VAN DINGENEN F. & LANDAU B. 2018. - The lower Pliocene gastropods of Le Pigeon Blanc (Loire-Atlantique, northwest France). Part 5 * - Neogastropoda (Conoidea) and Heterobranchia (fine). Cainozoic Research 18 (2): 89-176.
- WOOD S. V. 1848. - A Monograph of the Crag Mollusca: or, Descriptions of Shells from the Middle and Upper Tertiaries of the East of England: Volume 1: Univalves. Cambridge University Press, Cambridge. https://doi.org/10.1017/CBO9781139680745
- REGTEREN ALTENA C. O. VAN, BLOKLANDER A. & POUDEROYEN L. P. 1954 - 1956. - De fossiele schelpen van de Nederlandse stranden en zeegaten. Basteria 18: 54 - 64, pls 1 - 4 (1, 1954); 19: 27 - 34, pls 5 - 8 (2, 1955); 20: 81-90, pls 9 - 12 (3, 1956).
- THOMPSON T. E. 1988. - Molluscs: Benthic opisthobranchs (Mollusca: Gastropoda). Synopses of the British Fauna (new series) 8: 356.