Fissurellidae, Fleming, 1822

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 : 29-30

Key to species of Fissurellidae found in the GB (see also Bogi & Giusti 1994 for differentiating Emarginula spp. )

1. Anterior part of the aperture with a deep slit reaching the edge ....................................................... 2

– Anterior part of the aperture entire, shell with a slit or a hole not reaching the edge ....................... 4

2. Shell height> half length, commarginal sculpture of tightly packed, vermiculate cordlets .............. ................................................................................ Emarginula christiaensi Piani, 1985 ( Fig. 4I–J )

– Shell height ≤ half length, commarginal cords elevated and narrower than intervals ...................... 3

3. Apex definitely overhanging the posterior edge of the shell .............................................................. .......................................................................... Emarginula tuberculosa Libassi, 1859 ( Fig. 4F–H )

– Apex not overhanging the posterior edge of the shell ........................................................................ ......................................................................... Emarginula multistriata Jeffreys, 1882 ( Fig. 4D–E )

4. Shell with a hole situated at the apex or close to it ........................................................................... 5

– Shell with a slit situated between the apex and the anterior edge .................................................. 10

5. Apex retaining coiled part with larval shell, and the hole immediately anterior to it ...................... 6

– Apex without coiled part, with the hole situated on it ...................................................................... 7

6. Shell height> shell length, shell surface smooth ............................................................................... ............................................... Profundisepta alicei (Dautzenberg & H. Fischer, 1897) ( Fig. 6C–D )

– Shell height ≤ shell length, radial sculpture of granulose riblets ........................................................ ....................................................................... Profundisepta profundi (Jeffreys, 1877) ( Fig. 6E–G )

7. Shell usually large, with a sculpture of radial and commarginal riblets ............................................. ..................................................................... Diodora tenuiclathrata ( Seguenza, 1863) ( Fig. 4A–C )

– Shell always smaller than 10 mm with a sculpture of minute granules ............................................ 8

8. Granules arranged along radial lines ................ Fissurisepta granulosa Jeffreys, 1883 ( Fig. 6A–B )

– Granules arranged quincuncially ...................................................................................................... 9

9. Shell height nearly twice shell length ................. Cornisepta rostrata ( Seguenza, 1863) ( Fig. 6H–J )

– Shell height about the same as shell length ........................................................................................ ........................................ Cornisepta microphyma (Dautzenberg & H. Fischer, 1896) ( Fig. 6K–M )

10. Shell sculpture formed by definite radial ribs intersecting commarginal cordlets ............................. ............................................................. Puncturella asturiana (P. Fischer, 1882) [not found on GB]

– Shell sculpture formed by radial rows of granules, aligned to form ribs ........................................11

11. Apex strongly curved, overhanging posterior edge ............................................................................ ...................................................................... Puncturella granulata ( Seguenza, 1863) ( Fig. 4K–L )

– Apex weakly curved, not overhanging posterior edge ....................................................................... .................................................................................... Puncturella agger Watson, 1883 ( Fig. 5A–N )

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.

Fig. 6. Fissurellidae 3. A–B. Fissurisepta granulosa Jeffreys, 1883. Galicia Bank, 590–900 m, shell figured in Rolán Mosquera & Pérez Gándaras (1981), 3.2 mm. C–D. Profundisepta alicei (Dautzenberg & H. Fischer, 1897), BANGAL 0711, V5, 1631 m, 2.2 mm. E–G. Profundisepta profundi (Jeffreys, 1877), SEAMOUNT 1, DW116, 985–1000 m, 3.2 mm. H–J. Cornisepta rostrata (Seguenza, 1863), SEAMOUNT 1, DW116, 985–1000 m, 4.8 mm height. K–M. Cornisepta microphyma (Dautzenberg & H. Fischer, 1896), BANGAL 0711, V4, 744 m, 5.6 mm height. Scale bars: A–I, K–L = 1 mm; J, M = 500 µm.

Fig. 5. Fissurellidae 2. Puncturella agger Watson, 1883. A–C. BANGAL 0711, GOC6, 903 m, 4.0 mm. D–F. SEAMOUNT 1, DW116, 985–1000 m, 4.0 mm, SEM micrographs of protoconch and sculpture. G–I. SEAMOUNT 1, DW116, 985–1000 m, 4.4 mm.J–L. Syntype (NHMUK 1887.2.9.130), Challenger expedition, Station 24 (18°38′30″ N, 65°5′30″ W) off Culebra Island, West Indies, 390 fathoms [713 m], 4.1 mm, courtesy and © NHMUK. M–N. Galicia Bank, campaigns 1980‒1981 by Instituto de Investigaciones Pesqueras de Vigo-CSIC, 590–900 m, same specimen figured as Puncturella profundi (Jeffreys, 1887) in Rolán Mosquera & Pérez-Gándaras (1981: 6, pl. 1 fig. 4), and Rolán Mosquera (1983: 68), 6.0 mm. Scale bars: A–D, G–M = 1 mm; E–F = 200 µm.