We identified a total of three species of Geodia, all new records for this area: G. macandrewii (Bear Seamount), G. barretti (Muir Seamount) and G. megastrella (Picket, Kelvin, Manning and Muir Seamounts). Their distributions are shown in Fig. 1. We succeeded in sequencing the two mini-barcodes for all three species, including the 161-year-old holotype of G. barretti. Morphological and molecular studies were concordant. Collecting information and identifications results are available in the PANGAEA data repository (doi:10.1594/PANGAEA.867276).
Class DEMOSPONGIAE Sollas, 1885
Subclass HETEROSCLEROMORPHA Cárdenas et al., 2012
Order TETRACTINELLIDA Marshall, 1876
Suborder ASTROPHORINA Sollas, 1887
Family GEODIIDAE Gray, 1867
Genus Geodia Lamarck, 1815
Geodia macandrewii Bowerbank, 1858
Material
YPM 28261, Bear Seamount, 39°53′N, 67°26′W to 39°52′N, 67°23′W, Yankee 36 otter trawl, net depth: 1,489 m, R/V Delaware II cruise DE02–06, st. 46, coll. J. A. Moore, 29 July 2002 (preservation not recorded, not likely formalin).
YPM 27001, Bear Seamount, 39°55.22′N, 67°28.83′W to 39°54.24′N, 67°29.80′W, Yankee 36 otter trawl (1-h trawl), 1,826–2,008 m, R/V Delaware II cruise DE00–11, st. 17, coll. J. A. Moore, 5 December 2000 (frozen on board, then fixed in 70% ethanol).
Outer morphology (Figs. 2c, 3)
YPM 27001 is a large bowl-shaped specimen, 40 cm in diameter, with a flattened top surface (Fig. 3a). YPM 28261 is smaller with a more inflated top surface (Fig. 3b). Cribriporal pores (0.5–1 mm in diameter) are on the sides, cribriporal to uniporal oscules on the top surface (0.5–1 mm in diameter); cortex is 1–2 mm (YPM 27001) or 1–1.5 mm (YPM 28261) thick. Cortex is white; the choanosome is also white, a bit creamer. YPM 28261 has parasitic Hyrrokkin sp. foraminifera (Fig. 3c) deeply settled in the cortex, only in the pore areas (Fig. 3b) (identification on pictures by T. Cedhagen, Aarhus University, Denmark).
Spicules, YPM 28261
Megascleres:
(a) Oxeas I: length, 4,025 μm (n = 1); width, 25 μm (n = 1). (b) Oxeas II (= microxeas): mostly straight but sometimes slightly bent; length, 262–318.8–360 μm; width, 7.5–9.3–11 μm. (c) Orthotriaenes: rhabdome length, 2,825–6,642–7,920 μm (n = 10); width, 40–106–120 μm (n = 15); clad length, 230–690–1,000 μm (n = 10). (d) Anatriaenes: rhabdome length, >15 mm; width, 40–40.6-42 μm (n = 3); clad length, 260 μm (n = 1). (e) Promesotriaene: rhabdome width, 11 μm (n = 1); clad length, 260 μm (n = 1); central clad length, 200 μm (n = 1).
Microscleres:
(f) Sterrasters (Fig. 4a): spherical to slightly elongated; length, 167–196.1–217 μm; width, 155–175.4–195 μm; thickness, 122–150 μm. (g) Spheroxyasters: rough, 7.5–11–15 μm in diameter. (h) Oxyasters: rough; diameter, 17–19.6–25 μm.
COI barcoding and mini-barcoding
We managed to sequence the universal Folmer barcoding fragment for YPM 27001 (Genbank no. KX982850), it is 100% identical to all other G. macandrewii sequenced previously (e.g., EU4422198) (Cárdenas et al. 2011, 2013): nine sequences from Norway (four), Spitsbergen (two), Porcupine Bank (one), Davis Strait (one) and Flemish Cap (one). The universal mini-barcode sequence of YPM 28261 was 100% identical to the first 130 bp of the Folmer fragment of G. macandrewii, this was the first blast hit.
Bathymetric range
157–2,012 m (Cárdenas et al. 2013; this study).
Remarks
With its moderately thick cortex (1–2 mm), its very hairy sides and cribriporal pores and oscules, these specimens look like typical G. macandrewii. Furthermore, spicule measurements are perfectly in accordance with the description of the species (Cárdenas and Rapp 2015; Cárdenas et al. 2013). G. macandrewii was only collected in the Bear Seamount (seamount closest to the continental shelf, Fig. 1) but underwater pictures suggest it is also present in the Retriever Seamount (Fig. 2c), ~100 km from Bear Seamount (Fig. 1). Both of these seamounts are now protected as part of the Northeast Canyons and Seamounts Marine National Monument. Sightings in the Retriever Seamount were at 2,012 m depth, making it the deepest record for this species. The foraminifera could be the common parasitic Hyrrokkin sarcophaga Cedhagen 1994 described in the Northeast Atlantic on Geodia sponges, including G. macandrewii (Beuck et al. 2008; Cedhagen 1994) but genetic data are wanting to confirm this identification.
Geodia megastrella Carter, 1876
Material
YPM 28870, Muir Seamount, 33°46.54′N, 62°34.29′W, DSV Alvin dive 3885, st. 1, 2,027 m, R/V Atlantis cruise AT07–35, coll. D. Scheirer and R. Waller, 3 June 2003 (fixed in formalin).
YPM 28891, Muir Seamount, 33°45.20′N, 62°45.10′W, DSV Alvin dive 3887, st. 5, 2,265 m, R/V Atlantis cruise AT07–35, coll. J. Adkins and L. Robinson, 6 June 2003 (fixed in formalin).
YPM 58540, Muir Seamount, 33°45.20′N, 62°45.10′W, DSV Alvin dive 3887, st. 5, 2,265 m, R/V Atlantis cruise AT07–35, coll. J. Adkins and L. Robinson, 6 June 2003 (fixed in formalin).
YPM 34730, Kelvin Seamount, 38°50.992′N, 63°55.572′W, DSV Alvin dive 3904, st. 208–1, 1,880 m, R/V Atlantis cruise AT08–01, coll. S. C. France and I. G. Babb, 16 July 2003 (fixed in formalin).
YPM 36027, Manning Seamount, 38°08.09′N, 61°06.965′W, ROV Hercules dive 6, St. MAN708, 1,718 m, R/V Ronald H. Brown cruise RB04–04, coll. J. A. Moore, 15 May 2004 (preservation not recorded).
YPM 46869, Picket Seamount, 39°39.14052′N, 65°56.600400′W, DSV Alvin dive 4162, st. PIC 104–1, 1,995 m, R/V Atlantis cruise AT12–01, coll. L. Mullineaux and S. Eltgroth, 28 October 2005 (fixed in formalin).
Outer morphology (Figs. 2a, 5)
YPM 28870, 46869, 34730 and 58540 are large subspherical specimens. Diameters range from 8 cm (YPM 46869) to 20 cm (YPM 58540). YPM 28891 is more flattened (6 × 5 cm). All samples have one single preoscule opening (0.3–1.5 cm in diameter) on the top surface except for YPM 34730 that has two (Fig. 5b). Smaller preoscule openings (3–4 mm) have raised margins (YPM 36027). On the sides, cribriporal areas (2–3 mm in diameter) have characteristic ‘snowflake’ shapes (Fig. 5d). Specimens are not compressible with a very hard and thick cortex (1.5–3 mm). Surface is smooth, to human-skin-like, to beehive-like patterns. YPM 28891 and 58540 are growing on coral rubble; YPM 36027 is growing on dead Lophelia skeleton, while YPM 46869 was attached to the base of live Paragorgia. External color alive and in ethanol is brown to light brown. Internal color alive and in ethanol is cream (lighter than cortex).
Spicules, YPM 28870, unless stated otherwise.
Megascleres:
(a) Oxeas I: straight or slightly bent, some are slightly centrotylote; length, 2,600–2,998–3,680 μm (n = 7); width, 35–46.8–60 μm (n = 7). (b) Oxeas II (= microxeas): straight or slightly bent, with very sharp tips; length, 225–372.4–570 μm; width, 3.5–6.8–7.5 μm. (c) Orthotriaenes: rhabdome length, 3,160–3,480 μm (n = 2); width, 90–97–110 μm (n = 10).
Microscleres:
(d) Sterrasters: spherical to subspherical (Fig. 4b), 195–212.6–225 μm in diameter; thickness, 155–160 μm; sterrasters in the rest of the specimens are more elongated (sometimes lemon-shaped) (Fig. 4c). (e) Strongylasters: 5.0–7.2–10 μm in diameter. (f) Oxyasters I: 5–9 rough actines; diameter, 73–90.5–105 μm (Fig. 4b-c); oxyasters in YPM 34730, 28891 and 36027 have many oxyasters reduced to 3–2 actines, which often makes much larger oxyasters (diameter, 60–121.3–187 μm in YPM 34730) with actines up to 90 μm long. (g) Oxyasters II: thin rough actines; diameter, 15–29.4–50 μm. Anatriaenes and protriaenes not observed.
COI mini-barcoding
Identical universal mini-barcodes (130 bp) were obtained for three samples (out of six): YPM 028891, YPM 046869 and YPM 034730. Identical Depressio-minibarcodes (296 bp) were obtained for two samples: YPM 028891, YPM 046869. These Depressio-minibarcodes are 100% identical with a G. megastrella sequence from the Gulf of Cadiz (ZMAPOR 21231, Genbank no. HM592741) but have 1-bp difference with two other G. megastrella sequences from Scotland and Irving Seamount (south of the Azores) (Cárdenas et al. 2011). Two merged mini-barcode sequences (YPM 028891, 046869) were submitted to Genbank (KX982851–KX982852).
Bathymetric range
200–2,600 m (Cárdenas and Rapp 2015; Topsent 1911).
Remarks
Spicule measurements and external morphology are perfectly in accordance with previous descriptions from the Mid-Atlantic Ridge and Madeira (Cárdenas and Rapp 2015; Topsent 1928). Lemon-shaped sterrasters have also been observed in MNHN-DT1298 from Madeira, 2380 m (Topsent 1928). Contrary to its sister species in the Depressiogeodia clade (the boreal G. barretti and the arctic G. hentscheli) (Cárdenas et al. 2011), this species is not known to form mass occurrences (i.e., sponge grounds). This species was sighted (Fig. 2a) and collected between 1,719 and 2,265 m depth on several NES (Picket, Kelvin and Manning) and Muir Seamount (Fig. 1). Although the Depressio-minibarcodes are identical to the COI sequence of G. megastrella ZMAPOR 21231, the external morphology and spicule sizes of the latter are slightly different from our specimens (and those from the Mid-Atlantic Ridge or Madeira), thus suggesting the presence of genetically cryptic species with identical COI in this already suspected species complex (Cárdenas et al. 2011). This is the first time that this typical deep-sea northeastern Atlantic Geodia is recorded on the northwestern side. This G. megastrella morphotype (identical to the specimens from Madeira and the Mid-Atlantic Ridge) can therefore be added to the growing list of deep-sea amphi-Atlantic boreo/arctic/temperate demosponges (Cárdenas et al. 2013; Cárdenas and Rapp 2015).
Geodia barretti Bowerbank, 1858
Material
YPM 28886, Muir Seamount, 33°45.42′N, 62°36.06′W, DSV Alvin dive 3886, st. 1, 2,829 m, R/V Atlantis cruise AT07–35, coll. T. Shank and S. Eltgroth, 5 June 2003 (preservation not recorded, probably formalin).
Outer morphology (Fig. 6)
Spherical, 6 cm in diameter, regular short hispidity, slightly compressible, light-brown external color, cream color inside (lighter), one elevated preoscule (3.5 mm in diameter), slightly flexible cortex = 1 mm, radial skeleton organization, Pores areas <1 mm, on the bottom half of the sphere. Dichotriaenes/pro(meso)triaenes/anatriaenes crossing the surface.
Spicules, YPM 28886
Megascleres:
(a) Oxeas I: slightly bent, some are slightly centrotylote; length, 860–2,328–3,680 μm (n = 12); width, 16–34.9–50 μm (n = 10). (b) Oxeas II (= microxeas): straight or slightly bent; length, 262–470.2–600 μm; width, 5–7.6–17 μm. (c) Dichotriaenes: rhabdome length, 2,520–2,768–3,000 μm (n = 12); width, 110–126–140 μm (n = 11); protoclad length, 200–243-300 μm (n = 15); deuteroclad length, 200–284-360 μm (n = 15). (d) Anatriaenes: only observed at the surface, not measured. (e) Mesotriaenes: clads are sickle shaped; rhabdome length, 1,475 μm (n = 1); width, 5–12.3–17 μm (n = 3); clad length, 170–253–300 μm (n = 3); central clad length, 20–50–70 μm.
Microscleres (Fig. 4d):
(f) Sterrasters: spherical; 85–114.5–125 μm in diameter; thickness, 95–97 μm. (g) Strongylasters: 5–6.4–10 μm in diameter. (h) Oxyasters I: rough actines, a few have a single much longer actine (up to 72 μm long); diameter, 38–47.7–65 μm. (i) Oxyasters II: thin actines; diameter, 12.5–24.9–38 μm.
COI mini-barcoding
The universal mini-barcode and Depressio-minibarcode were both sequenced. The resulting merged sequence (Genbank no. KX982853) was 100% identical to the COI haplotype 1 of G. barretti (e.g., EU442195).
Bathymetric range
30–2,829 m (Cárdenas and Rapp 2013; this study)
Remarks
Spicule measurements are in accordance with the description of the species (Cárdenas et al. 2013). A few differences are, however, noted. This specimen has the largest sterrasters (85–114.5–125 μm) measured to date for this species. Since there seems to be a relation between depth and size of sterrasters (Cárdenas and Rapp 2013), this may be related to the fact that this is the deepest record of G. barretti. Also, unlike previous observations in G. barretti, there is no clear size distinction between oxyasters I and II in this specimen; it is more of a continuum. Moreover, the large oxyasters with a single unusually long actine found here had never been observed in G. barretti before, or even in North Atlantic Geodia species. Finally, the relatively dark brown color and the hispidity of this specimen are also atypical for this species (Cárdenas et al. 2013). All these small differences suggest that the Muir Seamount may somehow represent a separate population. This is the western-most record of this species in the Atlantic and although no specimens were collected in the NES, its presence on the Muir Seamount suggests its presence in the neighboring NES. The carnivorous sponge Abyssocladia polycephalus Hestetun et al. 2016 was found growing on this specimen.
To test the use of the two mini-barcodes on old type material, we tried to get mini-barcodes from the dry holotype of Geodia barretti (NHM 1877.5.21.1399) collected in 1855. Although DNA could not be detected in our extract, we succeeded in sequencing the COI universal mini-barcodes and the Depressio-minibarcodes (following the PCR protocols detailed above), thus obtaining a total of 416 bp from this 161-year-old type. The merged sequence, submitted to the Sponge Barcoding Project (SBP no. 1647, Genbank no. KX982854), was 100% identical to the COI haplotype 1 of G. barretti.