Cylichnium oliviforme, (Watson, 1883)

Gofas, Serge, Luque, Ángel A., Oliver, Joan Daniel, Templado, José & Serrano, Alberto, 2021, The Mollusca of Galicia Bank (NE Atlantic Ocean), European Journal of Taxonomy 785 (1), pp. 1-114 : 71-73

Cylichnium oliviforme ( Watson, 1883)

Fig. 30H‒J

Utriculus oliviformis Watson, 1883: 332.

Utriculus sp. – Watson 1886: 648, pl. 48 fig. 6.

Utriculus oliviformis – Dautzenberg & Fischer 1896: 400.

Cylichnium oliviforme ( Watson, 1883) – Fechter 1979: 37–38.

Material examined

GALICIA BANK • 7 sh; 42°56.77′ N, 11°58.53′ W; 1631 m; 2 Aug. 2011; BANGAL 0711 V5; MNCN • 6 sh; 42°41.87′ N, 11°26.71′ W; 1720 m; 8 Aug. 2011; BANGAL 0711 V10; MNCN .

Remarks

This species was described tentatively by Watson (1883) and later retracted by Watson (1886) on the grounds of poor condition of the material examined, originating from off the Azores in 1000 fathoms (1850 m). The species was again found off the Azores by Dautzenberg & Fischer (1896) and confirmed as valid. It was later reported from off the NW Iberian Peninsula by Fechter (1979) and transferred to the genus Cylichnium Dall, 1908. The size given 0.32 inches (8.1 mm) and the depth of the type locality are in good agreement with our material. Bouchet (1975) reported Cylichnium africanum ( Locard, 1897) from R/V “ Thalassa ” stn X 336 in southern Bay of Biscay (44°11′ N, 05°10′ W, 1850‒2050 m). He considered it distinct from Cylichnium oliviforme because, in his words, the latter is more distinctly flattened below the suture and has a finely reticulated sculpture in the upper part of the last whorl. Nevertheless, according to these characters we consider the shell figured by Bouchet (1975: pl. 4, c) as conspecific with our material. Conversely Locard (1897: pl. 2 figs 15‒19) illustrated, to represent his Aceras africana , a shell in which the last whorl almost completely covers the spire whereas both the type of C. oliviforme and our specimens have a descending last whorl. Therefore, we follow Fechter (1979) in using the name C. oliviforme for the Iberian species.

Figures

Fig. 30. Heterobranchia 3 (Scaphandridae, Philinidae, Retusidae). A–B. Scaphander punctostriatus (Mighels & C.B. Adams, 1842), BANGAL 0711, V2, 1706 m. 5.8 mm. C. S. punctostriatus, SEM micrograph of the sculpture of the body whorl, BANGAL 0711, V5, 1631 m. D–E. Laona quadrata (Wood, 1839), BANGAL 0711, V5, 4.4 mm. F–G. Pyrunculus ovatus (Jeffreys, 1871), BANGAL 0711, V5, 3.8 mm. H–I. Cylichnium oliviforme (Watson, 1883), BANGAL 0711, V10, 1720 m, 7.6 mm. J. Same specimen, detail of microsculpture of last whorl. K–L. Acteocina interrogens Gofas & Luque sp. nov., holotype (MNCN 15.05/200141H), BANGAL 0711, V4, 744 m, 2.4 mm. Scale bars: A–B, D–I, K–L = 1 mm; C, J = 200 µm.