Ushanaia ferruginea Kessel & Alderslade & Bilewitch & Schnabel & Norman & Potts & Gardner 2022, gen. et sp. nov.

Ushanaia ferruginea gen. et sp. nov.

urn:lsid:zoobank.org:act: B82A7D8A-03FB-4B8B-93F8-B02DA463A319

Figs 1B, D, 2I, 28A, 29–30

Diagnosis

Colonies encrusting, orange with white polyps. Collaret and points may be colourless or orange and consist of slender, often flattened, warty spindles. Tentacles contain irregular, warty, scale-like sclerites. Polyp neck contains abundant tuberculate to warty rod-like sclerites. Polyp mounds contain larger warty rod-, spindle-, and club-like forms. Surface contains radiates, grading into more elongated warty clubs. Interior with warty radiates.

Etymology

The species name is the Latin ‘ ferruginea ’, meaning ‘rusty or rust-coloured’ and referring to the colour and encrusting habit of the examined specimens.

Material examined

Holotype NEW ZEALAND • Northland, ~ 8 km SE of Cape Brett; 35.2160° S, 174.4033° E; depth 99–105 m; 6 Jul. 2009; Oceans Survey 2020 exped.; stn TAN0906/38; NIWA 156313.

Paratypes NEW ZEALAND – Northland • 4 specimens (and several small fragments); ~ 16 km ESE of North Cape; 34.4650° S, 173.2115° E; depth 140–141 m; 13 Jul. 2009; Oceans Survey 2020 exped.; stn TAN0906/134; NIWA 24533 • 3 specimens; ~ 27 km SE of North Cape; 34.5570° S, 173.28533° E; depth 139–141 m; 13 Jul. 2009; Oceans Survey 2020 exped.; stn TAN0906/132; NIWA 56056 • 3 specimens; ~ 22 km NE of Whangaroa Bay; 34.8302° S, 173.8940° E; depth 149–151 m; 9Jul. 2009; Oceans Survey 2020 exped.; stn TAN0906/93; NIWA 55605 • 5 specimens (and several small fragments); same collection data as for holotype; NIWA 54984.

Additional material

NEW ZEALAND – Northland • 3 specimens; ~ 14 km E of North Cape; 34.4000° S, 173.1717° E; depth 249–252 m; 15 Oct. 1968; New Zealand Oceanographic Institute exped.; stn F933; NIWA 3976 • 4 specimens (and several small fragments); ~ 10 km E of North Cape; 34.4137° S, 172.1333° E; depth 133–210 m; 19 Apr. 1999; Coral Reef Research Foundation exped.; stn Z9742; NIWA 143081 • 2 specimens; ~ 8 km ESE of North Cape; 34.4398° S, 173.1297° E; depth 110–115 m; 15 Jul. 2009; Oceans Survey 2020 exped.; stn TAN0906/181; NIWA 24532 • 3 specimens; ~ 16 km NE of Mahinepua / Stephenson Island; 34.8502° S, 173.9050° E; depth 132–134 m; 19 Jul. 2009; Oceans Survey 2020 exped.; stn TAN0906/236; NIWA 57457 • 1 specimen; ~ 15 km NE of Mahinepua / Stephenson Island; 34.8760°S, 173.9158° E; depth 114–117 m; 19 Jul. 2009; Oceans Survey 2020 exped.; stn TAN0906/235; NIWA 57364 • 2 specimens; ~ 15 km SE of Cape Brett; 35.2402° S, 174.4827° E; depth 135–139 m; 6 Jul. 2009; Oceans Survey 2020 exped.; stn TAN0906/42; NIWA 55022 • 1 specimen; ~ 15 km SE of Cape Brett; 35.2417° S, 174.4833° E; depth 128–133 m; 6 Jul. 2009; Oceans Survey 2020 exped.; stn TAN0906/36; NIWA 54943 • 1 specimen; ~ 3.5 km NE of Whananaki; 35.4858° S, 174.5012° E; depth 59–63 m; 5 Jul. 2009; Oceans Survey 2020 exped.; stn TAN0906/21; NIWA 54723. – Bay of Plenty • 2 specimens; ~ 18 km WSW of Whakaari / White Island, Rungapapa Knoll; 37.5497° S, 176.9707° E; depth 155–176 m; 5 Nov. 2000; NIWA exped.; stn KAH0011 /40; NIWA 142902. – NE coast of South Island • 6 specimens; ~ 65 km E of Pegasus Bay, Pegasus Canyon; 43.4172° S, 173.5315° E; depth 115 m; 14 May 2011; Oceans Survey 2020 exped.; stn TAN1108/24; NIWA 74201.

Description (holotype, NIWA 156313)

Colony form

The holotype encrusts a ~ 15 cm long sponge fragment and consists of ~10 raised, fleshy mounds, which contain polyps and are joined together by ribbon-like membranes (Fig. 28A). These mounds range from a few millimetres up to several centimetres across, are up to ~ 5 mm thick, and range from pale to bright orange (ethanol-preserved), fading to beige towards their edges. The membranes are very thin (<1 mm) and vary from pale-orange to beige. Polyps are concentrated towards the thicker parts of colony patches where they grow with a somewhat irregular spacing, but a few isolated polyps grow directly from the thin connective membranes between patches. Polyps are white, 0.75 mm to 2 mm tall when expanded, with collaret and points ranging from colourless to orange (Fig. 2I). Larger polyps tending to occur on thicker sections of the colony. Other polyp-bearing mounds encrusting the sponge that are not joined to the holotype are considered as paratypes.

Sclerites

Points are composed of slender, warty spindles (~ 0.25–0.45 mm long), many of which are flattened (Fig. 29A). Proximally, the spindles become larger and slightly more crescentic (~ 0.4–0.6 mm long), transitioning into a transverse orientation and merging with the collaret, which is usually around eight to twelve rows deep (Figs 2I, 29A, E). The tentacles contain irregular, warty, scale-like forms, often slightly crescentic (~ 0.1–0.25 mm long) (Fig. 29B). Tuberculate to warty rod-like sclerites (~ 0.08– 0.18 mm long) are abundant in the polyp neck (Fig. 29C). Larger warty rod- and spindle-like forms (~ 0.12–0.25 mm long), some of which can be club-like, form a densely packed surface layer in the polyp mounds (Fig. 29D). The rest of the surface layer (of fleshy areas) between polyp mounds contains radiates which grade into more elongated, warty clubs (~ 0.08–0.2 mm long) (Fig. 30A). Sclerites of the interior (of fleshy areas) are more uniformly comprised of warty radiates (~ 0.08–0.18 mm long) (Fig. 30B).

Variability

NIWA 54723, NIWA 55022 and NIWA 142902 are encrusting gorgonian fragments and NIWA 74201 is encrusting chaetopterid worm tubes.All other specimens are encrusting sponges.All preserved specimens are similar in growth form, varying only in the sizes of colony patches. In the examined specimens, colony patches reach up to ~ 8 cm long, with some encircling their sponge substrates completely. Specimens vary only slightly in colour (Fig. 28A). All fifteen lots are very similar in their sclerite compositions, varying only minimally in some size ranges, but these always fall within those described for the holotype (Figs 29–30).

Comparisons

Ushanaia ferruginea gen. et sp. nov. can easily be distinguished from U. fervens gen. et sp. nov. by the far more brightly and conspicuously coloured collaret and point sclerites in the latter (compare Figs 2I– J, 28A and 2M, 28B, 31). Additionally, specimens of U. ferruginea lack distal clubs in their points, which are present in U. fervens (compare Figs 29A and 32B). Ushanaia ferruginea also possesses large, very uniform rod/spindle-like sclerites in polyp mounds, which are distinctly different from the irregular forms present in U. fervens (compare Figs 29D and 33A). Beyond this, the surface and interior sclerites of specimens of U. ferruginea are overall noticeably more robust than those of U. fervens (compare Figs 30 and 33B–C). Note also that U. ferruginea has so far been collected only from considerably greater depths than U. fervens (~ 60–250 m vs <30 m).

Specimens of Ushanaia ferruginea gen. et sp. nov. do not form fleshy lobes to the same extent as U. solida gen. et sp. nov., and also clearly differ from this species in having polyps that are typically around twice as large (up to 2 mm vs up to 1 mm), and in lacking the distinctive, broad, flattened collaret and point sclerites found in U. solida (compare Figs 29A and 35A).

Habitat and distribution

While most specimens were collected off the east coast of far northern New Zealand, NIWA 142902, collected from the Bay of Plenty, and NIWA 74201, collected from Pegasus Canyon off the east coast of Waiponamou/South Island, suggest that Ushanaia ferruginea gen. et sp. nov. may be widely distributed at depths of ~ 60–250 m around New Zealand (Fig. 1B–D). Collection notes indicate that the species occurs in areas with a range of substrates, including muddy bottoms, gravels and shell debris, and is commonly associated with a high density of sponges and/or tube worms. Ushanaia ferruginea also occurs syntopically with K. amicispongia gen. et sp. nov., as several specimens of each were collected alongside the other.