Ophiactis nidarosiensis Mortensen 1920
Creators
- 1. Museums Victoria, GPO Box 666 E, Melbourne, 3001, AUSTRALIA,
- 2. Natural History Museum of Luxembourg, 24 Rue Münster, 2160 Luxembourg
Description
Ophiactis nidarosiensis Mortensen, 1920
Ophiactis nidarosiensis Mortensen, 1920: 60–63, fig. 5.— Mortensen 1933a: 346–347, fig. 58a.— Mortensen 1936: 264.— Alva & Vadon 1989: 839, fig. 5c–d.— Olbers et al. 2019: 250–252, fig. 254–255.
Material examined. MD 50 DC108, MNHN IE.2009.1590 (2). MD 50 DC114, MNHN IE.2009.1591 (3). MD 50 CP149, MNHN IE.2009.1592 (3). MD 50 DC157, MNHN IE.2009.1593 (4).
Comparative Material. Ophiactis hirta Lyman, 1879: Eltanin 15/1343, Southeast Pacific Basin, North Of Amundsen Sea, 54° 50´S, 129° 50´W, 567–604 m, 7/11/1964, USNM E52227 (2). EXBODI/CP3893, Mont Vauban Partie Sud-Est, 22° 24.1´S, 171° 46.9´E, 786–814 m, 19/9/2011, MNHN IE. 2007.6981 (2). SLOPE/32, South of Point Hicks, 38° 21.9´S, 149° 20´E, 1000 m, 23/7/1986, MV F90159 (17). TAN1402/57, Censeam Guyot, Stratum 4, 36° 54.47´S, 169° 50.78´W, 1013– 1010 m, 15/2/2014, NIWA 94253 (12).
Distribution. Arctic (150–560 m), NE Atlantic (810–1095 m), E Atlantic (175–423 m), S Africa (102–200 m). SPA (135–510 m).
Remarks. The MD 50 specimens are small (<1.5 mm dd) and have six arms, two distal oral papillae, fanshaped DAPs that are longer than wide with a convex distal edge and tapered proximal sides, 3 arm spines and an occasional disc spine. The smallest specimens have only 3 arms or show other signs of fissiparity.
Clark (1976) tentatively referred some small six-armed SPA specimens from 40–80 m to Ophiactis savignyi Müller & Troschel, 1842 on the basis that they had two distal oral papillae, truncate lower arm spines and fanshaped DAPs with a flattened distal edge. However, although the lower arm spines on the MD 50 specimens are widened compared to the upper one, they differ from O. savignyi in being terminated in a pointed thorny apex, and the DAPS are more droplet-shaped and show no sign of a truncate distal edge.
Instead, they are similar to equal-sized specimens of Ophiactis nidarosiensis from the Atlantic and Ophiactis hirta Lyman, 1879 from SE Australia/ New Zealand (e.g., MV F90159) which are also fissiparous. The similarity between these two species has been noted by Mortensen (1924). Both have six or more arms, two distal oral papillae, and DAPs that are longer or as long as wide with rounded distal margins. Mortensen (1924) stated that O. nidarosiensis differed in being fissiparous, oral shields with a distal lobe and relatively narrow VAPs. But all these characters can occur in SE Australian specimens that we have identified. Similar specimens that we have provisionally identified as O. hirta occur off New Caledonia, Louisville Ridge and the Heezen Fracture Zone of the south-central Pacific. Without genetic data it is unclear whether there is one or more cryptic species present across this wide distribution. In the interim, the SPA animals are treated as belonging to the species reported from South Africa.
Notes
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Linked records
Additional details
Identifiers
Biodiversity
- Collection code
- MNHN, IE , MV , NIWA , SLOPE , USNM
- Event date
- 1964-11-07 , 1986-07-23 , 2011-09-19 , 2014-02-15
- Family
- Ophiactidae
- Genus
- Ophiactis
- Kingdom
- Animalia
- Material sample ID
- NIWA 94253 , SLOPE/32
- Order
- Amphilepidida
- Phylum
- Echinodermata
- Scientific name authorship
- Mortensen
- Species
- nidarosiensis
- Taxon rank
- species
- Verbatim event date
- 1964-11-07 , 1986-07-23 , 2011-09-19 , 2014-02-15
- Taxonomic concept label
- Ophiactis nidarosiensis Mortensen, 1920 sec. O'Hara & Thuy, 2022
References
- Mortensen, T. (1920) Notes on some Scandinavian echinoderms, with descriptions of two new ophiurids. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening, 72, 45 - 79.
- Mortensen, T. (1933 a) Echinoderms of South Africa (Asteroidea: Ophiuroidea). Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening, 93, 215 - 400, pls. 8 - 19.
- Mortensen, T. (1936) Echinoidea and Ophiuroidea. Discovery Reports, 12, 199 - 348, 9 pls. https: // doi. org / 10.5962 / bhl. part. 8051
- Alva, V. & Vadon, C. (1989) Ophiuroids from the western coast of Africa (Namibia and Guinea - Bissau). Scientia Marina, 53, 827 - 845.
- Olbers, J. M., Griffiths, C. L., O'Hara, T. D. & Samyn, Y. (2019) Field guide to the brittle and basket stars (Echinodermata: Ophiuroidea) of South Africa. Brussels: Royal Belgium Institute of Natural Sciences.
- Lyman, T. (1879) Ophiuridae and Astrophytidae of the exploring voyage of H. M. S. Challenger under Prof. Sir Wyville Thomson, F. R. S. Part 2. Bulletin of the Museum of Comparative Zoology, Harvard University, 6, 17 - 83, pls. 11 - 19.
- Clark, A. M. (1976) Asterozoa from Amsterdam and St Paul Islands, southern Indian Ocean. Bulletin of the British Museum (Natural History), 30, 247 - 261, pls. 1 - 2. https: // doi. org / 10.5962 / bhl. part. 2384
- Muller, J. & Troschel, F. H. (1842) System der Asteriden. Braunschweig: Papier, Druck und Verlag.
- Mortensen, T. (1924) Echinoderms of New Zealand and the Auckland-Campbell Islands. II. Ophiuroidea. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening, 77, 91 - 177, pls. 3 - 4.