Velutinidae
Velutinidae is a family of small sea snails, marine gastropod molluscs in the clade Littorinimorpha.
Description
The length of the shell varies between 25 m mand 40 mm.The shell of these animals is very thin and delicate, and internal, completely covered by the mantle so the appearance of these animals more closely resembles that of dorid sea slugs rather than sea snails, but anatomically quite different. They are readily distinguished by the anterior siphon and typically snail-like, tentacle-bearing head beneath the
anterior mantle. There are no rhinophores or dorsal circlet of gills.
The shell is present but is completely internal. It is covered by a fleshy mantle. The ventral surface features a distinct foot and a head bearing tentacles with basal eyes. The anterior of the dorsal surface is indented along the midline, forming a short siphon. The mantle is relatively firm but has a somewhat gelatinous texture, appearing mostly smooth. The internal shell resembles an ear, being thin and fragile.
The colour is translucent, greyish-white to pinkish or yellow with black/brown spots and blotches. This colouration is variable, resembling that of the ascidian prey on which they live and feed and thus providing camouflage.
Taxonomy
The following two subfamilies were recognized in the taxonomy of Bouchet & Rocroi (2005):- Subfamily Velutininae J. E. Gray, 1840 - synonyms: Marseniidae Leach in Gray, 1847; Marsenininae Odhner, 1913; Capulacmaeinae Golikov & Gulbin, 1990; Onchidiopsinae Golikov & Gulbin, 1990 ; Marseniopsidae Badel, 1993
- Subfamily Lamellariinae A. D. d'Orbigny, 1841 - synonyms: Coriocellidae Troschel, 1848; Sacculidae Thiele, 1929 ; Pseudosacculidae Kuroda, 1933
Genera
Genera within the family Velutinidae include:Calyptoconcha- * Calyptoconcha pellucida A. E. Verrill, 1880 - translucent lamellariaCartilagovelutina Golikov & Gulbin, 1990
- * Cartilagovelutina beringensis
- * Cartilagovelutina chondrina
- * Cartilagovelutina cristata Ciliatovelutina Golikov & Gulbin, 1990Cilifera Golikov & Gulbin, 1990Coriocella Blainville, 1824 Echinospira Krohn, 1853Lamellaria G. Montagu, 1815Lamellariopsis Vayssière, 1906Limneria H. Adams & A. Adams, 1851Marseniella Bergh, 1886
- * Marseniella borealis Bergh, 1886Marsenina Gray, 1850Marseniopsis Bergh, 1886Mysticoncha Allan, 1936Onchidiopsis Bergh, 1853
- * Onchidiopsis glacialis M. Sars, 1851 - icy lamellaria
- * Onchidiopsis latissima Odhner, 1913
- * Onchidiopsis spitzbergensis Jensen, in Thorson, 1944Piliscus Lovén, 1859
- * Piliscus commodus Middendorff, 1851
- * Piliscus rostratus
- * Piliscus undulatus Pseudosacculus Hirase, 1928Pseudotorellia Warén, 1989
- * Pseudotorellia fragilis Warén, 1989Torellivelutina McLean, 2000Velutina [John John Fleming (naturalist)|Fleming (naturalist)|Fleming], 1820
- * Velutina plicatilis
- * Velutina schneideri Friele, 1886
- * Velutina velutina
Subfamily Velutininae Gray, 1840
;Genera brought into synonymy:Capulacmaea M. Sars, 1859 : synonym of Piliscus Lovén, 1859Chelinotus Swainson, 1840: synonym of Coriocella Blainville, 1824Cryptocella H. Adams & A. Adams, 1853: synonym of Lamellaria Montagu, 1815Marsenia Oken, 1823: synonym of Lamellaria Montagu, 1815Marvillia : synonym of Limneria H. Adams & A. Adams, 1851Morvillia Gray, 1857: synonym of Limneria H. Adams & A. Adams, 1851Oithonella Mörch, 1857: synonym of Marsenina Gray, 1850
- Oncidiopsis : synonym of Onchidiopsis Bergh, 1853Pilidium Middendorff, 1851: synonym of Piliscus Lovén, 1859Pseudoacculus : synonym of Pseudosacculus Hirase, 1928Sacculus Hirase, 1927: synonym of Pseudosacculus Hirase, 1928Velutella Gray, 1847: synonym of Velutina Fleming, 1820