Sympagella walleri, Goodwin, Claire E., Berman, Jade, Janussen, Dorte, Göcke, Christian & Hendry, Katharine R., 2016

Goodwin, Claire E., Berman, Jade, Janussen, Dorte, Göcke, Christian & Hendry, Katharine R., 2016, Hexactinellida (Porifera) from the Drake Passage (Southern Ocean) with a description of three new species, Zootaxa 4126 (2), pp. 207-220 : 213-214

Sympagella walleri sp. nov.

Type material. Holotype: MNHNCL POR-15003 Dried sample, small sub–sample rehydrated with Decon–90, tissue section and spicule preparation on slides. Sub-sample of above deposited as BELUM.Mc2015.365 (spicule preparation on slide only). Crusie sample number NBP1103–DH117–sponge01, 2nd June 2011, Sars Long Nose, Sars Seamount, 59° 45.846’S 68° 55.968’W, 930–1030m, Hein Dredge.

Paratypes: MNHNCL POR-15004 Dried sample, small sub–sample rehydrated with Decon–90, tissue section and spicule preparation on slides, Sub-sample of above deposited as BELUM.Mc2015.273 (spicule slide only). Cruise sample number NBP1103–DH91–sponge08 29th May 2011, Sars Seamount, 59° 43.10’S, 68° 52.0’W, 610– 680m, Hein Dredge; BELUM.Mc2015.313, cruise sample number NBP1103–DH97–sponge15, 30th May 2011, Sars Seamount, 59° 43.06’S 68° 52.23’W, 620–700m, Hein Dredge.

Other specimens (possibly fragments of the above): BELUM.Mc2015.266, cruise sample number NBP1103– DH91–sponge01 and BELUM.Mc2015.278, cruise sample number NBP1103–DH91–sponge13 both Sars Seamount, 59° 43.10’S, 68° 52.0’W, 610–680m, Hein Dredge; BELUM.Mc2015.299, cruise sample number NBP1103–DH97–sponge01, 30th May 2011, Sars Seamount, 59° 43.06’S 68° 52.23’W, 620–700m, Hein Dredge; BELUM.Mc2015.319 cruise sample number NBP1103–DH97–sponge21 Sars Seamount, 59° 43.06’S 68° 52.23’W, 620–700m, Hein Dredge; BELUM.Mc2015.371, cruise sample number NBP1103–DH117–sponge07, 2nd June 2011, Sars Long Nose, Sars Seamount, 59° 45.846’S 68° 55.968’W, 930–1030m, Hein Dredge.

Comparative material examined. BMNH 1908.9.24.28 Sympagella gracilis ( Schulze 1903) Holotype specimen.

BMNH 87.10.20.34 Sympagella johnstoni ( Schulze, 1886) Holotype specimen

BMNH 1887.10.20.35 Sympagella nux Schmidt, 1870 Holotype specimen

Etymology. Named after Dr Rhian Waller who was a principal investigator on RVIB Nathaniel B Palmer Cruise NBP11–03 on which these sponges were collected.

External morphology ( Figure 4 A). The type specimen is a thin walled cup approximately 15cm high with a diameter of 7cm at the osculum. The walls of the cup are 1–2mm thick. The specimen has been damaged during collection and the base is missing. The specimen is cream coloured and has a punctatesurface with small pores visible. When preserved (following drying and rehydration) the sponge is in the form of soft white lumps with a cotton wool like texture. The paratypes are fragments with a similar colour and texture but have been very badly damaged during collection so it is not possible to determine their original form.

Skeleton. The specimens were dried on collection and then rehydrated for examination. Consequently the tissue is not well preserved and it is difficult to see exact skeletal structure. There is a confused choanosomal skeleton of large diactins. Pinular hexactins are present at the surface of the sponge (it was impossible to determine if atrial and dermal categories differed as preservation was not good enough to determine location of these regions in the sponge). Strobiloplumicome and discohexaster microscleres are present throughout the tissue.

Spicules. Measurements unless specified are from the type specimen-measurements from the paratypes are given in Table 2 for comparison.

Choanosomal diactins ( Figure 4 B): 1441–(2601)–3736 by 11.3–(15.5)–26.7 µm abruptly pointed ends densely ornamented with small spines.

Hypodermal/hypoatrial pentactins ( Figure 4 C): With long proximal ray (495–(715)–1006 by 18.2–(25.0)–32.2 µm) and shorter tangential rays (232–(333)–415 by 15.9–(25.2)–33.2 µm). Ends densely ornamented with small spines.

Choanosomal hexactins ( Figure 4 D): Proximal ray (396–(625)–742 by 19.0–(26.2)–31.2 µm), distal ray (148– (449)–665 by 18.2–(26.6)–32.6 µm), tangential rays (231–(407)–594 by 15.9–(23.0)–33.2 µm) Ends densely ornamented with small spines.

Surface pinular hexactins ( Figure 4 E): Pinular ray (107–(125)–136 by 11.3–(19.2)–25.1 µm), proximal ray (56–(83)–113 by 6.4–(9.8)–13.5 µm), tangential rays (53–(95)–120 by 4.8–(9.2)–12.2 µm).

Discohexasters ( Figure 4 F): with usually two, sometimes three secondary rays per primary ray. 81–(92)–103 µm total diameter, centrum diameter 3.4–(5.2)–7.0 µm.

Strobiloplumicomes ( Figure 4 G,H): Rare in all of the specimens. The hook–like ends of the strobiloplumicomes are very fragile and often lost during spicule preparation ( Fig 4 G), a lateral view of a strobiloplumicome rosette with these hooks in place can be seen in Figure 4 H. No strobiloplumicomes were found to measure in the spicule preparations of the type specimens and those on the SEM preparations were at the wrong angle for measurements to be taken. Strobiloplumicomes of the paratypes are 11.0–20.9 µm total diameter with a centrum diameter of 1.9–2.9 µm.

Diagnosis. As these specimens possess strobiloplumicomes they are assigned to the sub-family Lanuginellinae . The lack of a second class of anchorate dermal pentactins, the possession of pinular hexactins and discoidal microscleres assigns them to the genus Sympagella . There are currently ten valid species in the genus (Table 3), one of these Sympagella johnstoni ( Schulze, 1886) was described from the southern Indian Ocean, between the Cape of Good Hope and the Kerguelen Islands, and has also been recorded from the Weddell Sea ( Janussen et al. 2004).

There are only three other species of Sympagella which do not possess oxyoidal microscleres: Sympagella ecomari Tabachnick & Menshenina, 2013 , Sympagella johnstoni ( Schulze, 1886) and Sympagella nux Schmidt, 1870 (Table 3). S. ecomari has much longer and thinner pinular rays on its surface hexactins (up to 267 µm) and larger strobiloplumicomes (29–58 µm); S. johnstoni , from examination of the type specimen, has more robust discohexasters and the pinules of its surface hexactins have a much larger width to length ratio, giving them a very bushy appearance; S. nux can be distinguished as it possesses pinular pentactins and its surface hexactins have much longer and more slender pinular rays.

Figures

FIGURE 4. Sympagella walleri sp. nov. Type specimen MNHNCL POR- 15003, strobiloplumicome image G from BELUM. Mc 2015.313. A. Collected specimen; B. End of diactin, scale bar 200 µm, light microscope; C. Dermal pentactin, scale bar 100 µm, illustration traced from light microscope image; D. Dermal hexactin, scale bar 100 µm, illustration traced from light microscope image; E. Pinular hexactin, scale bar 10 µm, SEM; F. Discohexaster, scale bar 10 µm, SEM; G, H. Strobiloplumicome, scale bar 10 µm, SEM.