Roxaniella jeffreysi

Roxaniella jeffreysi (Weinkauff, 1866)

Roxaniella jeffreysi @ Split, Croatia by Pero Ugarković

Taxonomic note: Originally described as Bulla (Cylichna) jeffreysi by Weinkauff (1866), based on material previously confused with other species of the genus Bulla. Subsequently, Monterosato (1884) erected the genus Roxaniella for this species; however, in much of the contemporary literature it has been treated as Atys jeffreysi, considering Roxaniella as a synonym or subgenus of Atys (Oskars et al., 2017). Recent studies based on molecular phylogeny have demonstrated that Mediterranean species traditionally assigned to Atys do not form a monophyletic group, suggesting affinities with different Indo-Pacific lineages and highlighting the taxonomic instability of the group (Oskars et al., 2017, 2019). In this context, the use of Roxaniella has been reinstated in recent works on the phylogeny of Haminoeidae sensu lato (Oskars et al., 2019), although its acceptance is not yet universal.

Synonyms

• Bulla blainvilliana Récluz, 1843
• Bulla ovulata Brocchi, 1814 sensu Jeffreys, 1856 (misidentification)
• Cylichna jeffreysi Weinkauff, 1866
• Atys jeffreysi (Weinkauff, 1866)

Description
Translucent animal, with the body covered by small white dots; the mantle, beneath the shell, shows irregular brown to reddish-brown blotches, also scattered over the cephalic shield and parapodial lobes (Oskars et al., 2017). The cephalic shield is short, broad, rounded, and bilobed, with well-defined small cephalic lobes; the eyes are visible through transparency. The parapodial lobes are triangular in shape (Oskars et al., 2017). The shell is translucent, whitish to yellowish in colour, cylindrical and truncated at both ends. The surface is covered by spiral striae extending over the entire shell, formed by fused rounded indentations, alternating thicker and thinner striae. Axial striae (growth lines) intersect the spiral ones, producing a characteristic decussate pattern. The aperture extends along the entire shell, narrowing towards the apex; the outer lip extends beyond the apex and arches towards the upper columella, without apical folds or torsion. The columellar lip shows a weak fold, and a small umbilical groove is present behind this fold (Oskars et al., 2017).

Biology
Specimens studied by Oskars et al. (2017) were collected between 40 and 60 m depth on Mediterranean sea bottoms, suggesting an affinity for relatively deep infra- and circalittoral habitats. No specific published information is available regarding the feeding or reproductive biology of this species.

Etymology

• Jeffreysi. In honor to John Gwyn Jeffreys, (1809-1885), solicitor from Swansea, who got interested in conchology already when young. By conchology Jeffreys meant not only shell collecting, but the total science about molluscs. He began to organize dredging expeditions, visiting the Shetlands, W. Scotland, Channel Islands, Norway etc. and accompanied by chosen specialists. He took part in some longer expeditions to W. Greenland and the Bay of Biscay and visited collecting colleagues in foreign countries. He could not come to terms with Darwinism, because, according to his view, it implied that no borders between species were to be found. “British Conchology” in 5 volumes 1862-69 is his main work. His very extensive shell collection was purchased for the Smithsonian Institution 1883 by W.H. Dall.

Distribution
The type locality of this species is La Spezia (Italy), on the coast of the Ligurian Sea (Mediterranean). The species has been documented in various areas of the Mediterranean and in the Macaronesian region (Madeira and Canary Islands) (Oskars et al., 2017; Moro et al., 2003). The specimens analysed in the redescription by Oskars et al. (2017) originate from Malta, confirming its presence in the central Mediterranean. The small size of the species and the scarcity of records may indicate that its actual distribution is insufficiently documented.

More pictures

Bibliography

1246567 Roxaniella jeffreysi 1 eunomia-revista-en-cultura-de-la-legalidad 50 creator asc 1 18306 https://opistobranquis.info/wp-content/plugins/zotpress/
Bibliography based on the works by Steve Long, 2006. Bibliography of Opisthobranchia 1554-2000 and Gary McDonald, 2009. Bibliographia Nudibranchia, with later updates from other resources.

Further reading

• Biodiversity Heritage Library
• Flickr pictures
• GROC
• IDscaro.NET
• Interim Register of Marine and Nonmarine Genera
• Medslugs (Med)
• NCBI GenBank
• OBIS - Search by Taxon
• World Register of Marine Species

Cite this article as: