Emarginula christiaensi Piani, 1985

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 : 30-32

Emarginula christiaensi Piani, 1985

Fig. 4I–J

Emarginula elata Locard, 1898: 82‒83 , pl. 4 figs 16‒18 (junior homonym of Emarginula elata Libassi, 1859 ) [figures erroneously called as pl. 4 figs 13‒15 in text and in plate caption].

Emarginula christiaensi Piani, 1985: 217‒219 , figs 65‒67 (replacement name).

Material examined

GALICIA BANK • 1 sh; 42°42′ N, 11°48′ W; 765 m; 18 Oct. 1987; SEAMOUNT 1 DW106 ; MNHN • 2 sh; 42°40′ N, 11°36′ W; 675‒685 m; 19 Oct. 1987; SEAMOUNT 1 DW111 ; MNHN • 1 sh; 42°52′ N, 11°51′ W; 985‒1000 m; 20 Oct. 1987; SEAMOUNT 1 DW116 ; MNHN • 1 sh; 42°39.95′ N, 11°36.42′ W; 615 m; 23 Jul. 2009; ECOMARG 0709 R2 ; MNCN .

Remarks

This species was never formally compared with Emarginula crassa Sowerby, 1813 , described as a Pliocene fossil in the Crag of Ipswich ( England) and reported in the Recent fauna of the British Isles and Scandinavia (Forbes & Hanley 1850: 481) and off NW Spain in 748‒1262 m ( Dautzenberg & Fischer 1897: 179). The latter species is differentiated by having a lower profile, with the apex more central and less curved backwards, and in having a more attenuated sculpture. In our experience, it has never been possible to differentiate the two species in the same locality, therefore they could represent at most geographical variants or subspecies of the same taxon. In the fossil record, Marquet (1995) separated subspecies Emarginula crassa crassa from E. crassa crassalta Wood, 1874 , which is very similar, if not identical, to E. christiaensi . However, both forms did not coincide in the same geological formation. More recently, Hoffman & Freiwald (2018) cited many empty shells of Emarginula christiaensi and two shells of E. crassa on the continental slope of Mauritania as if both were two different species, but they did not compare them and their figures do not show any differential character. The resolution of this taxonomic problem is beyond the scope of this work, but the name Emarginula crassalta Wood, 1874 , would have priority if it were the same as Emarginula christiaensi .

Figures

Fig. 4. Fissurellidae 1. A–C. Diodora tenuiclathrata (Seguenza, 1863), BANGAL 0711, GOC6, 903 m, 19.2 mm. D–E. Emarginula multistriata Jeffreys, 1882, SEAMOUNT 1, DW111, 675–685 m, 10.0 mm. F–H. Emarginula tuberculosa Libassi, 1859, SEAMOUNT 1, DW116, 985–1000 m, 6.1 mm. I–J. Emarginula christiaensi Piani, 1985, SEAMOUNT 1, DW106, 765 m, 20.0 mm. K–L. Puncturella granulata (Seguenza, 1863), SEAMOUNT 1, DW108, 1110–1125 m, 5.3 mm. Scale bars: A–C, I–J = 10 mm; D–H, K–L = 1 mm.