Seguenzia elegans Jeffreys 1885
Description
Seguenzia elegans Jeffreys, 1885
(Figs. 19–21)
Seguenzia elegans Jeffreys, 1876: 201 [nomem nudum].
Seguenzia elegans Jeffreys, 1885: 42 (pl. 5, fig. 1–1a); Clarke, 1959: 232; Clarke, 1961: 350 (pl. 2, figs. 5, 7; pl. 3, fig. 5); Abbott, 1974: 38; Gofas et al., 2001: 184, Segers et al., 2009: 5.
Seguenzia cf. elegans: Quinn, 1983b: 728 (figs. 5, 26).
Type locality: Porcupine Expedition, 1870, Atl. St. 16, 17, 17a, off the coast of Portugal, 740–1095 fathoms (ca. 1350–2000 m depth) (Jeffreys 1885).
Distribution: North Atlantic: Bay of Biscay, off Portugal (Jeffreys 1885); off Bermuda (Clarke 1959); off Yucatan, Mexico (Quinn 1983b). South Atlantic: Cape Basin and Argentine Basin (Clarke 1961).
New occurrence: Southeastern Brazil, Espírito Santo, from 1540 to 3450 m depths.
Description: Shell small, conical, relatively thin-walled, with stepped spire. Color translucent to nacreous glossy white. Protoconch (~1 whorl) prominent, bulbous, microporous; transition to teleoconch sometimes visible as an orthocline line, but not always well-marked. Teleoconch sculpture (except whorl base) consisting of strong spiral cords, with well-marked axial threads and very fine spiral threads between cord and suture; spire whorls bearing two visible spiral cords: a weaker subsutural one, and a stronger supramedian that produces a distinct keel; a third strong cord (though weaker than the supramedian) can be observed emerging below the abapical suture. Distance between axial riblets roughly equal to three times rib width; axial threads prosocline above median keel and opisthocline below it, creating a continuous sigmoid pattern. Whorl base sculptured by 8–10 spiral cords; axial threads between cords, becoming fainter toward umbilicus. Whorls slightly concave between spiral cords, but with overall rounded profile. Suture obscured by subsutural spiral cord. Aperture rounded quadrangular, with wellmarked callus, strong columellar tooth, and three labral sinuses: a deep subsutural sinus; a shallow sinus in peripheral part of basal region of aperture; and a very shallow sinus in palatal region of aperture, corresponding to the umbilical carina. Umbilicus narrow, deep, with well-marked (stronger than adjacent spiral cords) but smooth edge.
Measurements (in mm): 5¾–6¾ whorls, H = 2.7 ± 0.27; D = 2.50 ± 0.18; h = 1.37 ± 0.18; d = 1.02 ± 0.14. Material examined: Brazil: Espírito Santo: off São Mateus, continental slope of Abrolhos, 18°59’S 37°47’W, 1540–1550 m, MNHN, 11 shells, MZSP 116279, 5 shells (MD55, sta. DC70, 26/v/1987); 19°08’S 37°34’W, 3450 m, MNHN, 1 shell (MD55, sta. DS66, 25/v/1987).
Remarks: Specimens of S. elegans can be easily distinguished by their overall roundish profile and numerous and closely-packed spiral cords on the basal portion of the whorls. The species has an amphi-Atlantic distribution, but this is the first record from southern Brazilian waters.
Notes
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Linked records
Additional details
Identifiers
Biodiversity
- Family
- Seguenziidae
- Genus
- Seguenzia
- Kingdom
- Animalia
- Order
- Seguenziida
- Phylum
- Mollusca
- Scientific name authorship
- Jeffreys
- Species
- elegans
- Taxon rank
- species
- Taxonomic concept label
- Seguenzia elegans Jeffreys, 1885 sec. Salvador, Cavallari & Simone, 2014
References
- Jeffreys, J. G. (1885) On the Mollusca procured during the H. M. S. " Lightning " and " Porcupine " expedition, Part 9. Proceedings of the Zoological Society of London, 1885, 27 - 63. http: // dx. doi. org / 10.1111 / j. 1096 - 3642.1885. tb 02885. x
- Jeffreys, J. G. (1876) Preliminary report of the biological results of a cruise in H. M. S. Valorous to Davis Straits in 1875. Proceedings of the Royal Society, 25, 177 - 237. http: // dx. doi. org / 10.1098 / rspl. 1876.0043
- Clarke, A. H. Jr. (1959) New abyssal molluscs from off Bermuda collected by the Lamont Geological Observatory. Journal of Molluscan Studies, 33, 231 - 238.
- Clarke, A. H. Jr. (1961) Abyssal mollusks from the South Atlantic Ocean. Bulletin of the Museum of Comparative Zoology, 125 (12), 345 - 387.
- Abbott, R. T. (1974) American Seashells: The Marine Mollusca of the Atlantic and Pacific Coasts of North America. 2 nd Edition. Van Nostrand Reinhold Company, New York, 663 pp.
- Gofas, S., Le Renard, J. & Bouchet, P. (2001) Mollusca. In: Costello, M. J., Emblow, C. & White, R. (Eds.), European Register of Marine Species: A Check-List of the Marine Species in Europe and a Bibliography of Guides to Their Identification. Publications Scientifiques du M. N. H. N., Collection Patrimoines Naturels 50, Paris, pp. 180 - 213.
- Segers, W., Swinnen, F. & Abreu, A. (2009) An annotated checklist of the marine molluscs from the archipelagos of Madeira and the Selvagens (NE Atlantic Ocean). Bocagiana, 226, 1 - 60.
- Quinn, J. F. Jr. (1983 b) A revision of the Seguenziacea Verrill, 1884 (Gastropoda: Prosobranchia). I. Summary and evaluation of the Superfamily. Proceedings of the Biological Society of Washington, 96 (4), 725 - 757.