Latissimia ningalooensis Ekins, Benayahu & McFadden, 2022

Benayahu, Yehuda, Ekins, Merrick, Van Ofwegen, Leen P., Samimi-Namin, Kaveh & Mcfadden, Catherine S., 2022, On some encrusting Xeniidae (Octocorallia): Re-examination of the type material of Sansibia flava (May, 1898) and a description of new taxa, Zootaxa 5093 (4), pp. 421-444 : 433-436

Latissimia ningalooensis Ekins, Benayahu & McFadden , sp. nov.

Figures 1 , 11–14

http://zoobank/ urn:lsid:zoobank.org:act:33E744E2-542B-4CF6-85D1-DD020E4FD10B

Material. Australia. Holotype: QM G330711 , Ningaloo Reef , Western Australia , Australia (22.77661° S, 113.696432° E), patch reef, lagoon, 5–7 m, 20 May 2010, coll. M. Ekins & M. Bryce , NR10–030 ; Paratypes: QM G339754 , QM G339755 and WAM Z29359 same details as QM G330711 ; QM G330077 , Ningaloo Reef, inside Norwegian Bommies , Western Australia , Australia (22.62157° S, 113.6424° E), patch reef, lagoon, 5–6 m, 19 May 2010, coll. M. Ekins & M. Bryce, NR09–035; QM G334151 , Long Reef, Kimberley , Western Australia , Australia (13.83015° S, 125.83257° E), mid-littoral reef terrace, 0–1 m, 21 October 2010, coll. M. Ekins & M. Bryce, K-48; WAM Z59816 same details as QM G334151 ; QM G334150 , Long Reef, Kimberley , Western Australia , Australia (13.9018° S, 125.79108° E), sub-littoral reef platform, 2–5 m, 22 October 2010, coll. M. Ekins & M. Bryce, K–49; WAM Z59815 same details as QM G334150 ; QM G334196 , Champagney Islands, Kimberley , Western Australia , Australia (15.33074° S, 124.21692° E), intertidal, mid-littoral reef platform, Champagney Islands, Kimberley 1 m, 15 October 2011, coll. M. Ekins & M. Bryce, K-63; WAM Z54716 same details as QM G334196 ; QM G330421 , Montgomery Reef, Kimberley , Western Australia , Australia (15.897183° S, 124.323967° E), intertidal, mid-littoral reef terrace, 0–1 m, 19 October 2009, coll. M. Bryce, K-15; WAM Z54909 same details as QM G330421 . Other material: Brazil. SMNHTAU_ Co _38205 Rio de Janeiro , Ilha Grande Bay (23.026° S, 44.501° W), September 2017, coll. J. Creed: SMNHTAU_ Co _38206 same details .

Description. The holotype growing on a dead stony coral measures 11 x 9 mm ( Fig. 11A ), with a 1 mm thick spreading membrane with polyps. The polyps are usually 3.5 mm in height, and their body is 0.9 mm in width. The majority of the polyps are fully expanded, with only a small number partly contracted. They have two rows of 18–22 pinnules on either side of the tentacle. The relatively long and expanded polyps give the colonies a fleshy appearance.

The sclerites of the holotype are ellipsoid platelets, some with a median narrowing ( Fig. 12A ). Under a light microscope they are opalescent and abundant throughout the colony, measuring 0.010 –0.017 x 0.013 –0.023 mm in diameter. The sclerites are composed of calcite rods whose tips provide a granular microstructure to their surface, often forming a labyrinthic appearance and arranged in dense patches with some space in between ( Fig. 12B ). The sclerites often tend to fracture during the dehydration process necessary for SEM.

Color. The ethanol-preserved holotype has a pale brown membrane and polyp bodies and cream tentacles.

Etymology. The species name, ningalooensis , refers to Ningaloo, the type locality of the species.

Variation. The morphological features of the paratype colonies resemble the holotype, except in size ( Fig. 11

B–C).

Remarks. The paratypes of L. ningalooensis sp. nov. differ from the holotype by their size. This species is distinguished from L. opalia sp. nov. by its smaller polyps and sclerites, whose granular surface microstructure features a labyrinthic appearance. In addition, the species has fewer pinnules on the tentacles compared to its congener (18–22 vs. 24–30 pinnules). The ethanol-preserved holotype and paratypes of L. ningalooensis were sequenced and subsequently assigned to MOTU8 ( McFadden et al. 2019), unlike L. opalia which was assigned to MOTU72. The mean genetic distance (uncorrected p) between the two species was 0.2% at mtMutS and COI, and 1.1% at 28S rDNA.

The examined colonies of the xeniid that is invasive in Brazil (SMNHTAU_Co_38205 and SMNHTAU_Co_ 38206) are encrusting, featuring a spreading membrane and non-retractile polyps ( Fig. 13 ). The polyps feature two rows of 35–50 pinnules on either side of the tentacle, a higher number compared to the two rows of only 18–22 pinnules in the holotype. Their sclerites are ellipsoids, measuring 0.011 –0.013 x 0.016 –0.018 mm, and some have a median narrow waist ( Fig. 14A ). The sclerites are composed of calcite rods whose tips provide a granular appearance to the sclerite surface ( Fig. 14B ). The sclerites often tend to fracture during the dehydration necessary for SEM purposes. These two samples were sequenced and subsequently assigned to MOTU8, and therefore it is concluded that this invasive xeniid should be assigned to L. ningalooensis sp. nov. The morphological differences in pinnule number between the Brazilian and the West Australian material (see above) do not justify establishing a separate species and further indicate the problematic nature of pinnule count for species delineation among xeniid soft corals. In addition, the length of the polyp body varies greatly among the colonies of L. ningalooensis sp. nov. found in Brazil, from 3.5 mm to 3.75 cm (Mantellato et al. 2018), perhaps as a result of differing degrees of contraction.

Living features. The live colonies of L. ningalooensis from western Australia are light brown with a blue tinge that varies in strength ( Figs. 15A, B ). The colonies invasive to Brazil are encrusting ( Figs. 15C, D ) and exhibit a similar coloration, but their symbiotic algae may significantly mask the blue tinge. The colonies can extensively cover the hard substrate while displaying a mixed blue-brown coloration.

Distribution. North-western Australia, Northern Territory (Darwin), Brazil (introduced) ( Fig. 1 ).

Figures

FIGURE 1. Distribution map of the material examined in the current study. Color shades on the background represent different marine realms. TA = Tropical Atlantic, TSAM = Temperate Southern America, TSA = Temperate Southern Africa, WI-P = Western Indo-Pacific, CI-P = Central Indo-Pacific, and TAA = Temperate Australasia.

FIGURE 11. Latissimia ningalooensis gen. nov. sp. nov.: (A) Holotype (QM G330711) top and side view showing expanded polyps emerging from the encrusting spreading membrane. (B, C) Paratype colonies (QM G339754, and QM G339755).

FIGURE 12. Scanning electron micrographs of sclerites of Latissimia ningalooensis gen. nov. sp. nov. Holotype (QM G330711): (A) Ellipsoid platelets. (B) Tips of calcite rods provide a uniform granular appearance to the sclerite surface.

FIGURE 13. Colonies of Latissimia ningalooensis gen. nov. sp. nov., invasive to Brazil, featuring a spreading membrane and non-retractile polyps: (A) SMNHTAU_Co_38205. (B) SMNHTAU_Co_38206.

FIGURE 14. Scanning electron micrographs of sclerites of Latissimia ningalooensis gen. nov. sp. nov. invasive to Brazil (SMNHTAU_Co_38205): (A) Ellipsoid platelets with hexagonal outline. (B) Tips of calcite rods provide a granular appearance to the sclerite surface, organized in patches with space in between.

FIGURE 15. Live colonies of Latissimia ningalooensis gen. nov. sp. nov.: (A–B) Colonies from western Australia exhibiting mixed blue-brown coloration. (C–D) Encrusting colonies invasive to Brazil with their expanded polyps displaying mixed bluebrown color. Photos C–D courtesy of Joel C. Creed (Universidade do Estado do Rio de Janeiro).