Miscellanea Malacologica 4(4): 47-61, 31.X.2010

Skeneimorph species () from the Rockall and Hatton Banks, northeastern Atlantic Ocean

L. HOFFMAN1, B. Van HEUGTEN2 & M. S. S. LAVALEYE3 1Zoetermeer, the Netherlands ([email protected]), 2Oosterhout, the Netherlands ([email protected]), 3NIOZ, Texel, the Netherlands ([email protected])

ABSTRACT

A record is given on the occurrence and abundance of skeneimorph species in the families Trochaclididae, Pendromidae and (including those species formerly placed in ) that have been collected during the NIOZ expeditions to the Rockall and Hatton Banks (2004-2008). A description is provided for two new species: hattonensis, and Xyloskenea xenos (Skeneinae, Turbinidae, Gastropoda). Their holotypes have been deposited in the Zoological Museum Amsterdam (University of Amsterdam). Two poorly known species have been figured and re-described: tenera (Jeffreys, 1883), and nitidiuscula Jeffreys, 1883. Key words: Northeastern Atlantic Ocean, Rockall Bank, Hatton Bank, Turbinidae, Skeneidae, , Ganesa, Mikro, Xyloskenea, Granigyra, , new species, HERMES, Moundforce.

INTRODUCTION MATERIAL AND METHODS

The Rockall and Hatton Banks are sea bottom During expeditions conducted in 2004 (Mienis highs that have developed over Jurassic fault et al., 2004 [Moundforce]), 2005 (van Duyl et blocks. These fault blocks were formed during al., 2005 [HERMES]) and 2006 (Duineveld et early failed continental rifts in the Early al., 2006 [HERMES]), box core samples have Cretaceous. The failed rift systems are been taken from the coral-rich sea-bottom in preceding the successful rift that has developed the southeastern slope of the Rockall Bank and since the Cretaceous between the Western in 2008 (Lavaleye et al., 2008 [HERMES]) on European continent and the East Greenland the Hatton Bank. coastline in the North East Atlantic. The deep Whereas some of these box cores have Rockall Trough separates the Rockall Bank been preserved and retained for other from Ireland and Scotland. The Hatton Bank is investigations, other box core samples have the NW extent of the larger Rockall and Hatton been investigated for their malacofauna. Bank area. The Rockall Bank has a miniscule Unfortunately, the great majority of these island as a tip of a fault block in the North of samples only contained empty shells and, the structure. hence, no material has been available for The Hatton Bank is fully submerged. It anatomical studies. may be assumed that the sea bottom Bottom samples from box cores have environment in the Rockall-Hatton area has been washed thoroughly with fresh water, been in a stable state for at least 65 million dried and sieved in fractions of 10 mm, 3 mm, years, i.e. the end of the Cretaceous. These 1 mm, 0.5 mm. Fractions larger than 10 mm stable and isolated environments are known to and 3 mm contained mostly large coral develop endemic species. The highs of the fragments and few larger ; these have present day banks form a conglomerate of been hand picked. Fractions of 1-3 mm have cold-water coral reefs. A rich fauna been fully sorted under a microscope. The community populates these highs of which the fractions of 0.5-1 mm have been sampled and a most prominent groups are Mollusca, corals small volume has been fully sorted. The and sponges. remaining material has been enriched in a Typical water depths where these counter-current washing process and the communities thrive are 500-700 m on the enriched fraction has been fully sorted. The Rockall Bank to 600-1100 m on the Hatton smallest fraction has been fully enriched by Bank. The Royal Netherlands Institute for Sea counter-current washing and representative Research (NIOZ) has conducted detailed samples have been sorted. Taxonomy of the studies on the faunal communities of cold- specimen has been largely based on the online water corals in the NE Atlantic Ocean. CLEMAM database for European Mollusca.

47 Hoffman, Van Heugten & Lavaleye, 2010: Skeneimorph species

For all box core stations, statistical shell counts In this paper, we add two more new have been carried out such that species species in Skeneinae. Their holotypes have abundance by weight or sea-bottom area could been deposited in the Zoological Museum be estimated. Amsterdam. A few paratypes have been We have used as abundance unit retained in the collections of the authors. shells/kg-dry-sediment-weight and it must be realised that its large uncertainty is caused by inaccuracies introduced by sampling (location ABBREVIATIONS and depth of penetration) as well as in the information gathering (subjective hand sorting, CLEMAM = Check-List of European Marine visual counts, statistical extrapolations, Mollusca HERMES = Hotspot Ecosystem Research of the subjective taxonomic classification). Typical Margins of European Seas dry-weight sediment samples in the box cores n. sp. = new species contain 0.3-20 kg. For large sample sets with NIOZ = Royal Netherlands Institute for Sea high-related abundance it is not meaningful to Research, Texel specify the exact number of shells as this has ZMA = Zoological Museum Amsterdam often been based on statistical extrapolation of sub-samples. For rare species, frequently the ACKNOWLEDGEMENTS fully sorted shell set has been investigated but then the abundance is meaningless with only The authors express their appreciation to NIOZ few specimens available and it has been for allowing to work the unique material and to omitted consequently. publish the results of these studies. We greatly Representatives of most species have acknowledge the assistance of captain, crew, been digitally photographed using a technicians and scientists on board of RV stereomicroscope camera and a computer. ‘Pelagia’ during the cruises. Images have been taken as spherical slices at We particularly thank Robert G. regular focusing distances and the set of Moolenbeek (ZMA) for stimulating images have been synthetically combined into discussions, his knowledgeable advice on the one sharp image using Helicon Focus software. taxonomy and the provision of literature. He Alternatively, rare specimens have been has been most cooperative in allowing the first selected for SEM photography; they have been author to use the SEM facility at the University cleaned in a weak bleach solution, rinsed in of Amsterdam for micro-photographic fresh water, subjected to ultrasonic cleaning. pictures. Bram van der Bijl, Marien J. Faber Subsequently, they have been mounted for and an anonymous referee critically read the SEM photography. manuscript. The class of Archaeogastropoda and in particular the subfamily Skeneinae in the family Turbinidae is predominantly SYSTEMATICS represented in the malacofauna, both in terms of number of specimens as well in the number Family: Trochaclididae of species. In 2008, Hoffman et al. discussed four new skeneid species in the new Trochaclis islandicus Warén, 1989 Lopheliella from the Rockall Bank.

The holotypes of the genera Trochaclis islandicus Warén, 1989: 9-11, figs 6-7 Lopheliella, Mikro and Xyloskenea are in the collection of the Zoological Museum Material examined.- Amsterdam (formally part of University of ROCKALL BANK: Moundforce 2004/29, depth 1443 m, Amsterdam). All remaining material is either 1 shell; Hermes 2006/12, depth 1091 m, 3 shells; in the collection of the National Museum of HATTON BANK: Hermes 2008/36, depth 700 m, 9 Natural History ‘Naturalis’ in Leiden, the shells; Hermes 2008/117, depth 958 m, 12 shells. Netherlands or in the collections of the authors.

48 Miscellanea Malacologica 4(4): 47-61

Family: Pendromiidae Skenea areolata: Warén, 1991: 58, figs 3A-C

Rugulina fragilis (G.O. Sars, 1878) Material examined.- (Figs 1-3) ROCKALL BANK: Moundforce 2004/29, depth 1443 m; Moundforce 2004/41C, depth 784 m; Hermes 2005/15, Adeorbis fragilis G.O. Sars, 1878: 213, tab. 22, figs 19a-c depth 593 m; Hermes 2005/34, depth 767 m; Hermes Rugulina fragilis: Warén, 1991: 71-73, figs 11A-E, 13A- 2006/10C, depth 578 m; Hermes 2006/12, depth 1091 m; B Hermes 2006/23A, depth 578 m; Hermes 2006/56, depth 578 m; Hermes 2006/65, depth 1087 m; HATTON Material examined.- BANK: Hermes 2008/36, depth 700 m; Hermes 2008/92, ROCKALL BANK: Moundforce 2004/37, depth 557 m; depth 822 m; Hermes 2008/117, depth 958 m. Hermes 2005/15, depth 593 m; Hermes 2005/34, depth Abundances are 72.2 shells/kg at 400-600 m, 11.8 767 m; Hermes 2006/10C, depth 587 m; Hermes shells/kg at 600-800 m, 2.2 shells/kg at 1000-1200 m, 2.4 2006/12, 1091 m; Hermes 2006/23A, depth 578 m; shells/kg at 1443 m. Hermes 2006/56, depth 578 m; Hermes 2006/65, depth 1087 m; HATTON BANK: Hermes 2008/35, depth 796 m; Hermes 2008/36, depth 700 m; Hermes 2008/59, Skenea basistriata (Jeffreys, 1877) depth 788 m; Hermes 2008/92, depth 822 m. Abundances are 6.5 shells/kg at 400-600 m, 6.9 shells/kg at 600-800 Cyclostrema basistriata Jeffreys, 1877: 234 m, 2.7 shells/kg at 1000-1200 m. Skenea basistriata: Graham, 1988: 138, fig. 47 Skenea basistriata: Warén, 1993: 176, figs 16A-F, 17A-D Rugulina species Material examined.- (Figs 4-6) ROCKALL BANK: Hermes 2006/12, depth 1091 m;

Hermes 2006/65, depth 1087 m. Material examined.- HATTON BANK: Hermes 2008, St.117, depth 958 m, 1 fragmentary shell. Skenea larseni Warén, 1993

Description.- Skenea larseni Warén, 1993: 173, figs 11D-F, 12A, 12C, Fragile well rounded tonnoid-shaped shell, 12E, 13C, 14A-B, 15C-D height 2.3 mm, width 2.3 mm, with radial regular rib structure. Protoconch is eroded and Material examined.- hence unknown. Teleoconch whorls are well ROCKALL BANK: Moundforce 2004/41C, depth 784 rounded but somewhat oval in cross-section. m; Hermes 2005/15, depth 593 m; Hermes 2005/23, The base of the outline is a well-rounded base. depth 667 m; Hermes 2005/34, depth 767 m; Hermes The outer lip is sharp. The suture is shallow. 2006/10C, depth 578 m; Hermes 2006/12, depth 1091 m; Hermes 2006/23A, depth 578 m; Hermes 2006/56, depth Umbilicus is open and deep. The aperture is 578 m; Hermes 2006/65, depth 1087 m; HATTON prosocline. Sharp radial ribs dominate the BANK: Hermes 2008/35, depth 796 m; Hermes 2008/36, surface texture: about 21 on the body whorl. depth 700 m; Hermes 2008/92, depth 822 m; Hermes Fine prosocline growth lines are evident. The 2008/117, depth 958 m. Abundances are 22 shells/kg at 400-600 m and 13 shells/kg at 1000-1200 m. umbilical area is rather smooth. The single shell is somewhat translucent cream white. Skenea ossiansarsi Warén, 1991 Discussion.- The specimen has been placed in Rugulina in Skenea ossiansarsi Warén, 1991: 58-60, figs 4C-D, 6F, the family Pendromiidae because of its 9C-D superficial resemblance to R. fragilis. Once more complete specimen and/or soft parts are Material examined.- available, a more conclusive taxonomic ROCKALL BANK: Moundforce 2004/41C, depth 784 m; Hermes 2005/15, depth 593 m; Hermes 2005/23, placement can be made. depth 667 m; Hermes 2005/34, depth 767 m; Hermes 2006/10C, depth 587 m; Hermes 2006/12, depth 1091 m; Family: Turbinidae Hermes 2006/23A, depth 578 m; Hermes 2006/56, depth 578 m; Hermes 2006/65, depth 1087 m; HATTON Skenea areolata (G.O. Sars, 1878) BANK: Hermes 2008/35, depth 796 m; Hermes 2008/36, depth 700 m; Hermes 2008/59, depth 788 m; Hermes

2008/92, depth 822 m; Hermes 2008/117, depth 958 m. Cyclostrema areolatum G.O. Sars, 1878: 345, tab. 34, Abundances are 453 shells/kg at 400-600 m and 703 figs 6a-d shells/kg at 600-800 m, 118 shells/kg at 1000-1200 m.

49 Hoffman, Van Heugten & Lavaleye, 2010: Skeneimorph species

Skenea peterseni (Friele, 1877) BANK: Hermes 2008/36, depth 700 m; Hermes 2008/117, depth 958 m. Cyclostrema peterseni Friele, 1877: 3 Skenea peterseni: Warén, 1991: 60-61, figs 3F, 4A-B, 6D Skenea peterseni: Warén, 1993: 175, figs 11A-C, 12B, Skenea turgida (Odhner, 1912) 12D, 13B, 15A-B Cyclostrema turgidum Odhner, 1912: 79 Material examined.- Skenea turgida: Warén, 1991: 65, figs 5D, 5G, 7D, 9A ROCKALL BANK: Moundforce 2004/29, depth 1443 m; Hermes 2006/12, depth 1091 m; Hermes 2006/65, depth Material examined.- 1087 m. ROCKALL BANK: Moundforce 2004/29, depth 1443 m; Hermes 2006/12, depth 1091 m; Hermes 2006/65, depth 1087 m. Skenea polita Warén, 1993

Skenea polita Warén, 1993: 171-173, figs 10A-E, 13A Lopheliella hermesae Hoffman, van Heugten & Lavaleye, 2008 Material examined.- ROCKALL BANK: Moundforce 2004/12, depth 1443 m, Lopheliella hermesae Hoffman et al., 2008: 43, figs 16- 1 old shell. 19, 23

Material examined.- Skenea profunda (Friele, 1879) ROCKALL BANK: Hermes 2005/34, depth 767 m, holotype, 1 shell; Hermes 2005/15, depth 593 m, 1 shell; Cyclostrema profundum Friele, 1879: 272 Hermes 2005/23, depth 667 m, 1 shell; Hermes 2006/56, Skenea profunda: Warén, 1991: 65, figs 5C, 7B depth 578 m, 1 shell.

Material examined.- ROCKALL BANK: Moundforce 2004/29, depth 1443 m; Lopheliella moolenbeeki Hermes 2006/65, depth 1087 m. Hoffman, van Heugten & Lavaleye, 2008

Skenea rugulosa (G.O. Sars, 1878) Lopheliella moolenbeeki Hoffman et al., 2008: 41-42, figs 6-9, 21 Cyclostrema rugulosum G.O. Sars, 1878: 129, tab. 21, figs a-d Material examined.- Skenea rugulosa: Warén, 1991: 63-64, figs 3E, 4E-F, 6C, ROCKALL BANK: Hermes 2006/56, holotype, depth 9F 578 m, >200 paratypes; Moundforce 2004/37, depth 557 m, >200 shells; Hermes 2005/15, depth 593 m, 16 shells; Material examined.- Hermes 2005/23, depth 667 m, > 20 shells; Hermes ROCKALL BANK: Moundforce 2004/37, depth 557 m; 2005/34, depth 767 m, 4 shells; Hermes 2006/10C, depth Hermes 2005/34, depth 767 m; Hermes 2006/10C, depth 587 m, 36 shells. HATTON BANK: Hermes 2008/117, 578 m; Hermes 2006/12, depth 1091 m; Hermes 2006/56, depth 958 m, 1 shell. depth 578 m; Hermes 2006/65, depth 1087 m; HATTON BANK: Hermes 2008/35, depth 796 m; Hermes 2008/36, depth 700 m; Hermes 2008/59, 788 m; Hermes 2008/92, Lopheliella moundforceae depth 822 m; Hermes 2008/117, depth 958 m. Hoffman, van Heugten & Lavaleye, 2008 Abundances are 120 shells/kg at 400-600 m and 16 shells/kg at 600-800 m, 118 shells/kg at 1000-1200 m and Lopheliella moundforceae Hoffman et al., 2008: 42-43, 37 shells/kg at 1443 m. figs 10-15, 22

Material examined.- Skenea trochoides (Friele, 1876) ROCKALL BANK: Hermes 2006/28A, depth 588 m, holotype, 1 shell; Moundforce 2004/37, depth 557 m, 2 Cyclostrema trochoides Jeffreys MS - Friele, 1876: 60 worn shells; Moundforce 2004/41C, depth 784 m, 6 worn Skenea trochoides: Warén, 1991: 58, figs 2E-F, 3D, 3G, shells; Hermes 2005/23, depth 667 m, 4 shells; Hermes 6E, 8B 2006/10C, depth 578 m, 6 worn shells.

Material examined.- ROCKALL BANK: Moundforce 2004/29, depth 1443 m; Lopheliella rockallensis Hermes 2005/15, depth 593 m; Hermes 2006/12, depth Hoffman, van Heugten & Lavaleye, 2008 1091 m; Hermes 2006/65, depth 1087 m; HATTON

50 Miscellanea Malacologica 4(4): 47-61

Lopheliella rockallensis Hoffman et al., 2008: 41, figs 1- whorl is slightly sloping downwards. Above 5, 20 and below the suture, a remarkable etched

band is visible as a line on the Material examined.- ROCKALL BANK: Hermes 2006/St.56, holotype, depth microphotograph but it is not visible with a 578 m, >100 paratypes; Moundforce 2004/37, depth 557 normal stereomicroscope. This bands ends m, 30 shells; Hermes 2005/15, depth 593 m, 13 shells; abruptly at the anal side of the aperture. The Hermes 2005/23, depth 667 m, >20 shells; Hermes umbilicus is very narrow without umbilical 2005/34, depth 767 m, 11 shells; Hermes 2006/10C, groove. Outer lip is sharp and prosocline below depth 587 m, 7 shells; Hermes 2006/23A, depth 587 m, 2 shells. the suture; then follows a straight line until the periphery of the whorl; finally, with a marked curve leading to the basal part of the lip under gaudryi nearly 100º. A basal view clearly shows the (Dautzenberg and Fischer, 1896) prosocline aperture developing in a straight

Tharsis gaudryi Dautzenberg & Fischer H., 1896: 486, line from the centre to the periphery of the plate 21 figs 13-15 whorl. Callus is developed along the lip but is nearly absent along the columella. The surface Material examined.- appearance is smooth and glossy. Colour is HATTON BANK: Hermes 2008/117, 958 m. translucent cream white.

Locality.- Cirsonella romettensis Hermes 2005/23, N55.50337-W15.78590, (Granata-Grillo, 1877) depth 667 m, upper SE flank of the Rockall Oxystele romettensis Granata-Grillo, 1877: 5. Bank, one empty shell. The sediment sample Cirsonella romettensis: Warén, 1992: 160, figs 4C, 9E, contained fine biogenic silty clay. Living fauna 11C-E, 12A included the corals Madrepora and Stylaster as well as Actiniaria, Bryozoa, Tunicata and Material examined.- Bivalvia; dead fauna included Lophelia and ROCKAL BANK: Hermes 2006/St.65, 1087 m. Madrepora corals.

Ganesa nitidiuscula Jeffreys, 1883 Distribution.- (Figs 7-14) Jeffreys (1883) reported the species from between the Hebrides and the Faroes. We add Ganesa nitidiuscula Jeffreys, 1883: 94, plate 19 fig. 9 the Rockall Bank to its distribution. Ganesa nitidiuscula: Warén, 1992: 176, fig. 33A

Description.- Mikro hattonensis n. sp. A description has been added because a fresh (Figs 15-22) shell has been imaged for the first time with a SEM photograph and additional shell details Description of the holotype (ZMA Moll. can be provided. Warén (1992) figured only a 410023; Figs 15-22).- fragmentary topotype without apex; the Very small and elevated skeneimorph shell authors have not studied this shell. with keeled shoulder. Height 0.795 mm, width The skeneid shell is small, globose, 0.767 mm. Inflated protoconch with 1.2 whorls firm and glossy. Outline is slightly with a clear transition to the teleoconch but no cyrtoconoid. Height 1.91 mm, width 1.51 mm. varix is present. The surface structure of the Protoconch of slightly more than 1 whorl has a protoconch is eroded but it appears to be dimension of 230 x 173 μm with a rough smooth. Diameter of the protoconch is 130 μm. surface structure consisting of irregularly Teleoconch whorls are well rounded, and show shaped grains of 2-10 μm. Transition to the a keel at the shoulder. A strong radial rib teleoconch is marked by a clear varix. marks the upper edge of the keel. The start of Teleoconch has 3.2 well-rounded smooth the teleoconch shows a remarkably pitted whorls with occasionally a growth line. Suture structure both on the shoulder and on the is very shallow; the joint to the preceding immediate area below it. A ventral outline

51 Hoffman, Van Heugten & Lavaleye, 2010: Skeneimorph species shows a step-wise top, obese shell with a well- general shape, size and protoconch appear very rounded base. Surface texture of the peripheral similar but the protoconch of our species is area of the body whorl is smooth with many smaller. In M. hattonensis, the radial rib on the growth lines. The lip is sharp and slightly shoulder extends over the full spire and, in flared at the base. The suture is very shallow; contrast, it fades away on the teleoconch of M. the shoulder is straight. The umbilicus is open globulus. Finally, the pitting on top of the and deep. The umbilical area forms a wide teleoconch and in the umbilical area of M. spiral funnel with a pronounced elevated radial hattonensis is absent in M. globulus. ridge at the midst of the columella. The umbilical area is covered with numerous elongated pits and with some axial growth Akritogyra curvilineata Warén, 1992 lines. A weak spiral rib marks the umbilical Akritogyra curvilineata Warén, 1992: 162-163, figs 4F, area. The adjacent area on the body whorl also 13A-D, 15A, 16A-B shows less frequent pitting. The aperture is slightly opisthocline at the suture; aperture Material examined.- plane is slightly curved inwards (concave). HATTON BANK: Hermes 2008/117, depth 958 m, 1 Shell is opaque white. shell.

Variability.- Akritogyra similis (Jeffreys, 1883) Variability is poorly mapped. Maximum size is 1.5 mm; recorded from the Rockall Bank Cyclostrema simile Jeffreys, 1883: 92, plate 19, fig. 4 specimen. This specimen was in poor Akritogyra similis: Warén, 1992: 161-162, figs 13E-F, condition and an alternative shell was selected 14A-B, 15C for the holotype. The clearly adult specimen Material examined.- from Rockall has a flared lip / varix. ROCKALL BANK: Moundforce 2004/41C, depth 784 m; Hermes 2005/15, depth 593 m; Hermes 2005/23, Type locality.- depth 667 m; HATTON BANK: Hermes 2008/59, depth Hermes 2008/35, N58.74118 -W18.66255, 788 m. depth 796 m, Hatton Bank, holotype is based on an empty shell. Sediment sample contained Lissotesta minima (Seguenza, 1876) fine carbonate mud. Fauna included corals

(Anthozoa), Ophiuroidea and Polychaeta. Margarites minima Seguenza, 1876: 186. Lissotesta minima: Warén, 1992: 171-172, figs 25E-F, Type material.- 29A-C The holotype and one paratype have been found at the type locality. Moundforce Material examined.- 2004/29, N55.422-W15.611, depth 1443 m, ROCKALL BANK: Hermes 2006/65, depth 1087 m; HATTON BANK: Hermes 2008/117, depth 958 m, 1 one worn paratype with height 1.5 mm. All shell. shells were empty.

Distribution.- Lissotesta turrita (Gaglini, 1987) This species is only known from the Hatton and Rockall Banks. Cyclostrema turritum Gaglini, 1987: 5 Lissotesta turrita: Warén, 1992: 172-173, figs 26B, 30A- F Etymology.- The species is named after the type locality. Material examined.- ROCKALL BANK: Hermes 2006/65, depth 1087 m. Discussion.- Only a single genus in Skeneinae fits our new species: Mikro Warén, 1996. Mikro Anekes affinis (Jeffreys, 1883) hattonensis is very similar to the type species Mikro globulus Warén, 1996, which has been Cyclostrema affinis Jeffreys, 1883: 92, plate 19 fig. 5 Anekes affinis: Warén, 1992: 164-165, figs 18A-B, 19A described from Iceland. The keeled outline,

52 Miscellanea Malacologica 4(4): 47-61

Material examined.- slightly prosocline, nearly orthocline with a ROCKALL BANK: Hermes 2006/65, depth 1087 m; slight bend in the lip. Shell is translucent HATTON BANK: Hermes 2008/36, depth 700 m. white.

Locality.- Anekes paucistriata Warén, 1992 Hermes 2006/65, carbonate mud with coral Anekes paucistriata Warén, 1992: 165-166, figs 19D, debris, N55.452-W15.766, depth 1087 m, 20B-D, 21A, 22B Rockall Bank, one empty shell.

Material examined.- ROCKALL BANK: Hermes 2006/65, depth 1087 m. Retigyra millipunctata (Friele, 1886)

Cyclostrema millipunctatum Friele, 1886: 33, plate 11 Granigyra arenosa Warén, 1993 figs 17, 18, 18a Retigyra millipunctata: Warén, 1989: 6, figs 5A-E Granigyra arenosa Warén, 1993: 180-181, figs 18-20 Material examined.- Material examined.- HATTON BANK: Hermes 2008/36, depth 700 m; HATTON BANK: Hermes 2008/35, depth 796 m, 2 Hermes 2008/117, depth 958 m. shells.

Xyloskenea naticiformis (Jeffreys, 1883) Granigyra tenera (Jeffreys, 1883) (Figs 23-27) Cithna naticiformis Jeffreys, 1883: 112, plate 20 fig. 11 Xyloskenea naticiformis: Warén, 1996: 202-205, figs 3A- Cyclostrema tenerum Jeffreys, 1883: 91-92, plate 19 fig. D, 7C 2 Granigyra tenera: Warén, 1992: 176, fig. 33B Material examined.- ROCKALL BANK: Moundforce 2004/29, depth 1443 m, Description.- 1 eroded shell. A description has been provided because a fresh shell has been imaged for the first time Xyloskenea xenos n. sp. with a SEM photograph and microstructure (Figs 28-33) and a protoconch can be displayed.

The elevated skeneimorph shell has a Description of the holotype (ZMA Moll. rugose radial and axial surface structure. 410024; Figs 28-30).- Height 1.1 mm, width 1.2 mm. Protoconch Fragile elevated skeneimorph shell with with 1.1 whorls with a clear transition to the flattened apex and keeled umbilicus. The teleoconch; surface structure is granular with a height is 2.9 mm; the width is 3.3 mm. The few very fine spiral ribs. Size of the protoconch has a typical skeneid form with 1.3 protoconch is 180 x 240 μm. whorls but the surface has been eroded. Teleoconch whorls are very well Diameter of the protoconch is about 160 μm rounded, slightly oval towards the base. The and has a smooth surface. Teleoconch has 2.7 first half whorl of the teleoconch has numerous whorls that rapidly grow in diameter. axial growth ridges. Then radial ridges are The whorls are well rounded, weaved in at the second teleoconch whorl and somewhat globose, and they show weak yet these are ultimately dominating in the body clearly visible radial ribs covering the upper whorl; spacing between the radial ridges on the half of the whorls. Outline is flattened at the last whorl is about 10-20 μm. The outline is top ending in a well-rounded base. The lip is rather inflated ending in a well-rounded base. sharp. The suture is fairly deep. The umbilicus The outer lip is sharp thin and fragile. The is open, wide and deep. The umbilical area suture is deep initially but rather shallow in the shows a pronounced intra-umbilical keel with a body whorl; the joint is nearly perpendicular to sharp edge leaning towards the umbilical side. the previous whorl. Umbilicus is narrow, deep The aperture is prosocline and oval. Surface but tortuous. Regular spiral ribs and axial texture is fairly smooth with numerous fine ridges cover the umbilical area. Aperture is

53 Hoffman, Van Heugten & Lavaleye, 2010: Skeneimorph species growth lines. Shell is dull and white, even Portugal. The authors have also found this though the surface of the holotype has been species on the Rockall Bank. An obvious keel exposed to erosion. at the base of the whorl can easily distinguish X. naticiformis from X. xenos. The former Variability.- also lacks the weak radial rib structure. Variability is poorly known with only few specimens available. Maximum width is 3.3 mm. The initial whorls of subadult specimens Palazzia ausonia (Palazzi, 1988) are more flattened; only the single adult ausonia Palazzi, 1988: 103 specimen, i.e. the holotype, shows a body Palazzia ausonia: Warén, 1991: 75-77, figs 17A-G, 18A whorl with a suture well below the periphery of the penultimate whorl. The inside of the Material examined.- body whorl of the sub-adults is a bit glossy. ROCKALL BANK: Hermes 2006/65, 1087 m.

Type locality.- Palazzia planorbis (Dall, 1927) Hermes 2008/35, N58.74118 -W18.66255, depth 796 m, Hatton Bank, holotype is based Lippistes planorbis Dall, 1927: Art. 18, 131 on an empty shell. Sediment sample contained Palazzia planorbis: Warén, 1991: 75-77, figs 16A-D, fine carbonate mud. Fauna included corals 18B (Anthozoa), Ophiuroidea and Polychaeta. Material examined.- Type material.- ROCKALL BANK: Moundforce 2004/37, depth 557 m; Hermes 2006/10C, depth 587 m; Hermes 2006/12, depth The holotype and four paratypes have been 1091 m; Hermes 2006/65, 1087 m. found at the type locality. Hermes 2008/59, biogenic carbonate mud, N58.78065 – W18.58983, depth 788 m, one paratype. All Eudaronia aperta (Sykes, 1925) type specimens are empty shells. Omalogyra aperta Sykes, 1925: 192

Eudaronia aperta: Warén, 1991: 80, figs 14C-E, 18D Distribution.- This species is only known from the Hatton Material examined.- Bank. ROCKALL BANK: Hermes 2006/65, depth 1087 m.

Etymology.- Xyloskenea is known to live on sunken wood Adeuomphalus ammoniformis but there has been no mention of recovered Seguenza, 1876 wood from any of the box-core localities. The current species is considered a stranger (xenos Adeuomphalus ammoniformis Seguenza, 1876: 10 Adeuomphalus ammoniformis: Kano, Chikyu & Warén in Greek) at the type locality. 2009: 401-403, figs 1F-I

Discussion.- Material examined.- The genus Xyloskenea Marshall, 1988 shows ROCKALL BANK: Hermes 2006/65, depth 1087 m. the morphological features of the new species and they are known to exceed the size of 3 mm globally. Other genera in Skeneinae seldom Adeuomphalus densicostatus exceed this size in the NE Atlantic, only deep- (Jeffreys, 1884) water species of the genus Cirsonella Angas, Homalogyra densicostata Jeffreys, 1884: 129, plate 10 1877 (like Cirsonella ateles Dautzenberg & fig. 1 Fischer, 1896) form an exception but these Adeuomphalus densicostatus: Kano, Chikyu & Warén have a totally different shell. Xyloskenea 2009: 403-404, figs 1A-E naticiformis (Jeffreys, 1883) is the only known Material examined.- representative of Xyloskenea in the NE ROCKALL BANK: Hermes 2005/15, depth 593 m; Atlantic; see Warén, 1996. Xyloskenea Hermes 2006/12, depth 1091 m; HATTON BANK: naticiformis is known from off Iceland and off Hermes 2008/36, depth 700 m.

54 Miscellanea Malacologica 4(4): 47-61

Cantrainea globuloides Granata-Grillo G., 1877. Descriptions de (Dautzenberg & Fischer, 1896) quelques espèces nouvelles ou peu connues. Napoli: Salvatore Marchese. 16 pp. Leptothyra globuloides Dautzenberg & Fischer H. 1896: 175, plate 21 fig. 1 Hoffman, L., B. van Heugten & M. S. S. Material examined.- Lavaleye, 2008. A new genus and four new HATTON BANK: Hermes 2008/117, depth 958 m. species in the family Skeneidae (Gastropoda) from the Rockall Bank, northeastern Atlantic Ocean. Miscellanea Malacologica 3: 39-48 REFERENCES Jeffreys J. G., 1877. New and peculiar Dall W. H., 1927. Small shells from dredgings Mollusca of the Patellidae and other families off the southeast coast of the United States by of Gastropoda procured in the Valorous the United States Fisheries Steamer expedition. Annals and Magazine of Natural "Albatross", in 1885 and 1886. Proceedings of History (4)19: 231-243 the United States National Museum 70 (18): 1-134 Jeffreys J. G., 1883. On the Mollusca procured during the H. M. S. "Lightning" and Dautzenberg P. & H. Fischer, 1896. Dragages "Porcupine" expedition. Proceedings of the effectués par l'Hirondelle et par la Princesse Zoological Society of London: 88-115 Alice 1888-1895. 1. Mollusques Gastropodes. Mémoires de la Société Zoologique de France Jeffreys J. G., 1884. On the Mollusca procured 9: 395-498 during the H. M. S. "Lightning" and "Porcupine" expedition. Proceedings of the Duineveld, G. C. A [editor], 2006. Zoological Society of London: 111-149 Biodiversity, ecosystem functioning and food web complexity of cold water coral reefs in Lavaleye, M. S. S. [editor], 2008. HERMES the NE Atlantic (Rockall Bank). Cruise 2008 Coralfish2008, Belgica Mound 64PE249, Galway-Oban, 19 June – 7 July Province, Hatton Bank, Cruise Report 2006. Texel: NIOZ. 25 pp. (excluding 64PE291-292, Texel-Cork-Texel, 10-June – appendices) 16 July 2008. Texel: NIOZ. 90 pp.

Friele H., 1876. Bidrag til Vestlandets Mienis, F. & H. de Haas [editors], 2004. The Molluskenfauna. Forhandlinger I Viden- distribution, morphology, sedimentology and skapsselkabet I Kristiania 1875: 57-64 watermass characteristics of and around mounds in the Gulf of Cadiz and at the SW Friele H., 1877. Preliminary report on the Rockall Trough Margin. Cruise report, R.V. Mollusca from the Norwegian North Atlantic Pelagia, Moundforce 2004 (64PE229), 15 Expedition in 1876. Nyt Magazin for August - 9 September. Texel: NIOZ. 99 pp. Naturvidenskaberne 23: 1-10 Odhner, N. H., 1912. Northern and Arctic Friele H., 1879. Catalog auf der norwegischen Invertebrates in the Collection of the Swedish Nordmeer-expedition bei Spitzbergen State Museum. Prosobranchia, 1. Diotocardia. gefundenen Mollusken. Jahrbücher der Kungliga Svenska Ventenskapsakaemiens Deutschen Malakolozoologischen Gesell- Handlingar 54 (1): 1-274 schaft 6: 264-286 Palazzi, S., 1988. Note sugli Friele H., 1886. The Norwegian North mediterranei e maderensi. Bollettino Mala- Atlantic Expedition 1876-1878, Third cologico 24: 101-111 Volume, Zoology, Mollusca II. Christiania: Grøndahl & Søn, 44 pp. Rubio, F., L. Dantart & Á. A. Luque, 1998. Two new species of (Gastropoda,

55 Hoffman, Van Heugten & Lavaleye, 2010: Skeneimorph species

Skeneidae) from the Mediterranean coast of 31 pp. [excl. Appendices] Spain. Iberus 16: 81-93 Warén, A., 1989. New and little known Rubio, F., L. Dantart & Á. A. Luque, 2004. El Mollusca from Iceland. Sarsia 74: 1-28 género Dikoleps (Gastropoda, Skeneidae) en las costas ibéricas. Iberus 22: 115-132 Warén, A., 1991. New and little known Mollusca from Iceland and Scandinavia. Sars G. O., 1878. Bidrag til kundskaben om Sarsia 76: 53-121 Norges arktiske fauna: 1. Mollusca regionis Arcticae Norvegiae. Oversigt over de i Norges Warén, A., 1992. New and little known arktiske region forekommende bloddyr. skeneimorph gastropods from the Christiania: A.W. Brøgger, xv + 466 pp. Mediterranean Sea and the adjacent Atlantic Ocean. Bollettino Malacologico 27: 149-248 Seguenza G., 1876. Studii stratigrafici sulla formazione pliocenica dell’Italia Meridionale. Warén, A., 1993. New and little known Bollettino del reale Comitato Geologico Mollusca from Iceland and Scandinavia, Part d’Italia 7: 7-15 2. Sarsia 78: 159-201

Van Duil, F. C. & G. C. A Duineveld [editors], Warén, A. 1996. New and little known 2005. Biodiversity, ecosystem functioning and Mollusca from Iceland and Scandinavia, Part food web complexity of deep water coral reefs 3. Sarsia 81: 297-245 in the NE Atlantic (Rockall Bank and Porcupine Bank). Cruise 64PE238, Galway- Texel, 21 June – 21 July 2005. Texel: NIOZ.

56 Miscellanea Malacologica 4(4): 47-61

Figs 1-6. Genus Rugulina. 1-3. R. fragilis (G.O. Sars, 1878), Moundforce 2004/37, depth 557 m, Rockall Bank, height 2.2 mm; 1. Ventral view; 2. Basal view; 3. Surface structure body whorl; 4-6. R. species, Hermes 2008/117, depth 958 m, Hatton Bank, height 2.3 mm; 4. Ventral view; 5. Basal view; 6. Apical view.

57 Hoffman, Van Heugten & Lavaleye, 2010: Skeneimorph species

Figs 7-14. Ganesa nitidiuscula Jeffreys, 1883, Hermes 2005/23, N55.50337-W15.78590, depth 667 m, Rockall Bank, height 1.9 mm, width 1.5 mm; 7. Ventral view; 8. Side view; 9. Apical view; 10. Protoconch 230 x 173 m; 11. Ventral view (SEM); 12. Side view (SEM); 13. Apical view (SEM); 14. Surface structure protoconch.

58 Miscellanea Malacologica 4(4): 47-61

Figs 15-22. Mikro hattonensis n. sp., holotype, Hermes 2008/35, N58.74118 -W18.66255, depth 796 m, Hatton Bank, height 0.80 mm, width 0.77 mm; 15. Side view; 16. Ventral view; 17. Apical view; 18. Microstructure umbilical area; 19. Protoconch 200 x 140 m; 20. Ventral view (SEM); 21. Apical view (SEM); 22. Basal view (SEM).

59

Hoffman, Van Heugten & Lavaleye, 2010: Skeneimorph species

Figs 23-27. Granigyra tenera Jeffreys, 1883, Hermes 2006/65, carbonate mud with coral debris, N55.452-W15.766, depth 1087 m, Rockall Bank, height 1.1 mm, width 1.2 mm; 23. Ventral view; 24. Apical view; 25. Basal view; 26. Protoconch 240 x 180 μm; 27. Detail of body whorl structure.

60 Hoffman, Van Heugten & Lavaleye, 2010: Skeneimorph species

Figs 28-33. Xyloskenea xenos n. sp. Figs 28-30. Holotype, Moundforce Hermes 2008/35, N58.74118 -W18.66255, depth 796 m, Hatton Bank, height 2.9 mm, width 3.3 mm; 28. Ventral view; 29. Apical view; 30. Protoconch diameter 160 m; 31-33. subadult paratype, Hermes 2008/59, N58.78065 – W18.58983, depth 788 m, Hatton Bank, width 1.7 mm. 31. Ventral view; 32. Basal view; 33. Apical view.

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