Friday, July 19, 2019

[Mollusca • 2019] Calliostoma bullatum • Last Snails Standing Since the Early Pleistocene, A Tale of Calliostomatidae (Gastropoda) Living in Deep-water Coral Habitats in the north-eastern Atlantic


 Calliostoma bullatum (Philippi, 1844) on various substrates

in Hoffman, Beuck, van Heugten & Freiwald, 2019.

Abstract
Three species in the gastropod genus Calliostoma are confirmed as living in Deep-Water Coral (DWC) habitats in the NE Atlantic Ocean: Calliostoma bullatum (Philippi, 1844), C. maurolici (Seguenza, 1876) and C. leptophyma Dautzenberg & Fischer, 1896. Up to now, C. bullatum was only known as fossil from Early to Mid-Pleistocene outcrops in DWC-related habitats in southern Italy; our study confirmed its living presence in DWC off Mauritania. A discussion is provided on the distribution of DWC-related calliostomatids in the NE Atlantic and the Mediterranean Sea from the Pleistocene to the present.

Keywords: Mollusca, Calliostoma, deep-water coral associations, NE Atlantic Ocean, Mediterranean Sea, systematics

FIGURES 9–14. Calliostoma bullatum on various substrates. 
9. MSM16-3/GeoB 14871 (ROV4). Grazing on hydroids. 10. MSM16-3/GeoB 14871 (ROV4). Elongated, muscular foot supports feeding on polyp tissue (Madrepora oculata). Operculum and dorsal groove on foot indicated by arrow. 
11. MSM16-3/GeoB 14873 (ROV7). Muscular foot enables elevation of body above substrate (live Lophelia pertusa). Epipodial sense organs spread directly below the shell (arrow). 12. MSM16-3/GeoB 14871 (ROV4). Feeding on apical portions of a live Madrepora oculata
13. MSM16-3/GeoB 14779 (ROV2). Two individuals feeding on Lophelia pertusa tissue; note the grazing tracks showing the bare, white coral skeleton devoid of polyp tissue in contrast to the orange to pale-pinkish live portions. 14. MSM16-3/GeoB 14891 (ROV9). Three individuals of different sizes all feeding on epibionts of Lophelia pertusa framework; note the grazing traces on adjacent live Lophelia pertusa portions (see arrow). 
[Figs 9-20 were taken by ROV “Sperre”, Tomas Lundälv, Sven Lovén Centre for Marine Infrastructure, Tjärnö, University of Gothenburg, Strömstad, Sweden].

FIGURES 15–20. Calliostoma bullatum on substrates.
 15. MSM16-3/GeoB 14871 (ROV5). Grazing on carnivorous sponge Cladorhiza corallophila; arrow indicating grazing effect. 16. MSM16-3/GeoB 14902 (ROV10). On framework encrusting sponge.
17. MSM16-3/GeoB 14902 (ROV10). Grazing on a valve of live Acesta excavata, which is colonised by epibionts; the two laser points are at a distance of 6 cm. 18. MSM16-3/GeoB 14902 (ROV10). Grazing on a valve of dead Acesta excavata (note in direct surrounding the free portions of epibionts on the valve and the white framework portions of Lophelia pertusa lacking any tissue).
 19. MSM16-3/GeoB 14902 (ROV10). Grazing on a gastropod shell (Ranella olearium). 20. MSM16-3/ GeoB 14891 (ROV9). Grazing on dead hydroid axis in close vicinity to a Solenogastres.

Leon Hoffman, Lydia Beuck, Bart van Heugten and André Freiwald. 2019. Last Snails Standing Since the Early Pleistocene, A Tale of Calliostomatidae (Gastropoda) Living in Deep-water Coral Habitats in the north-eastern Atlantic.  Zootaxa. 4613(1); 93–110. DOI: 10.11646/zootaxa.4613.1.4

No comments:

Post a Comment