Southern Ocean Asteroidea: a proposed update for the Register of Antarctic Marine Species.

BACKGROUND: The Register of Antarctic Marine Species (RAMS, De Broyer et al. 2015) is the regional component of the World Register of Marine Species (WoRMS Editorial Board 2015) in the Southern Ocean. It has been operating for the last ten years, with a special effort devoted towards its completion after the International Polar Year (IPY) in 2007-2008, in the framework of the Census of Antarctic Marine Life (CAML, 2005 - 2010). Its objective is to offer free and open access to a complete register of all known species living in the Southern Ocean, building a workbench of the present taxonomic knowledge for that region. The Antarctic zone defined by this dynamic and community-based tool has been investigated with a particular interest. The Sub-Antarctic zone was a secondary objective during the establishment of the RAMS and is still lacking the impulse of the scientific community for some taxa. NEW INFORMATION: In the present study, more than 13,000 occurrences records of Asteroidea (Echinodermata) have been compiled within the RAMS area of interest and checked against the RAMS species list of sea stars, using WoRMS Taxon Match tool. Few mismatches (basionym mistakes : i.e. original name misspelled or incorrect) were found within the existing list and 97 unregistered species are actually occurring within the RAMS boundaries. After this update, the number of Asteroidea species was increased by around 50%, now reaching 295 accepted species.

Introduction

The Register of Antarctic Marine Species, RAMS

RAMS is a collaborative and dynamic information system managing Southern Ocean marine taxon names and related information (De Broyer et al. 2015). The main objective of RAMS is to establish a benchmark of the present taxonomic knowledge of the Southern Ocean biodiversity (De Broyer et al. 2011).

In a recent appraisal of RAMS, Jossart et al. (2015)​ underscored the number of 10,294 described species of which 8,297 are accepted marine species (viz. checked by taxonomic experts). Among these species, 537 (~6.5%) were reported as accepted species names for echinoderms and 198 (~2.4%) as accepted names for sea star species.

After 10 years of service, RAMS still displays several spatial gaps, especially with regards to species occurring in the sub-Antarctic zone, described as the area below the sub-Tropical front (Deacon 1984, Rintoul 2007) and North of the Polar Front.

In order to complete the taxonomic information for the class , we propose in this work an updated version of the checklist of Southern Ocean sea stars species occurring within the RAMS area of interest.

Materials and methods

Area of interest

As described in De Broyer and Danis (2011) the RAMS area of interest is extending from the coast of the Antarctic continent to the sub-Tropical front. Convenient operational limits have been defined (Table 1; Fig. 1), splitting the Southern Ocean into two zones: the Antarctic zone and the sub-Antarctic zone.

Table 1.

RAMS area of interest. Operational northern limits in the different sector of the Southern Ocean for both the Antarctic zone and the sub-Antarctic zone.

Sector	Longitude range	Northern limit
Antarctic zone
South Atlantic Sector	60°W-50°W	57°S
	50°W-30°E	50°S
Indian Sector	30°E-80°E	50°S
	80°E-150°E	55°S
South Pacific Sector	150°E-60°W	60°S
Sub-Antarctic zone
Atlantic & Indian Sectors	60°W-140°E	43°S
South Pacific Sector	140°E-176°W	48°S
	176°W-80°W	45°S
	80°W-72°W	41°S

Figure 1.

Occurrences of RAMS (light grey dots) and Proposed-RAMS (orange dots) sea star species. The Antarctic zone is located below the green line and the Sub-Antarctic zone between the green and dark red lines. The Polar Front (black line) and the Sub-Tropical Front (dashed black line) are also shown.

Data collection

More than 13,000 occurrences records were agregated from different sources including global information systems such as the Ocean Biogeographic Information System (OBIS), the Global Biodiversity Information Facility (GBIF), initiatives such as the Biogeographic Atlas of the Southern Ocean (De Broyer et al. 2014), historic records mined from the literature pertaining to the early exploration of the Southern Ocean (e.g. Sladen 1889), recently published checklists (e.g. Gutt et al. 2014) or unpublished cruise records. Only the specimens identified at a species level, regardless of their depth (shelf, slope, deep-sea)  were kept for the preparation of this checklist.

The validity of each species name was controlled using the Taxa Match Tool available in RAMS (http://www.marinespecies.org/rams/aphia.php?p=match) and WoRMS (http://www.marinespecies.org/aphia.php?p=match) to ensure its validity and presence in the RAMS checklist.

Data resources

Complete checklist of Southern Ocean Asteroidea

The data underpinning the analyses reported in this paper are deposited at GBIF, the Global Biodiversity Information Facility, http://ipt.pensoft.net/resource?r=southern_ocean_asteroidea&v=1.1

Checklists

Checklist of RAMS species

(Sladen, 1883)

(Sladen, 1883)

(Koehler, 1912)

(Koehler, 1920)

(Sladen, 1889)

(Bell, 1908)

(Koehler, 1912)

(Koehler, 1906)

(Perrier, 1875)

(Lütken, 1857)

Perrier, 1875

(Koehler, 1920)

(Koehler, 1920)

Koehler, 1923

(E. A. Smith, 1876)

(Verrill, 1876)

(Koehler, 1920)

(Bell, 1881)

Perrier, 1891

(deLoriol, 1894)

Fisher, 1940

Fisher, 1940

(E. A. Smith, 1876)

Perrier, 1875

Müller & Troschel, 1842

Sladen, 1889

Ludwig, 1903

(Sladen, 1885)

Clark, 1962

Bernasconi, 1966

Bernasconi, 1972

(Perrier, 1881)

(Sladen, 1889)

(Koehler, 1907)

Ludwig, 1903

(Studer, 1884)

(Sladen, 1889)

Sladen, 1889

(H.E.S. Clark, 1971)

Koehler, 1908

H.L. Clark, 1923

Fisher, 1940

(Philippi, 1858)

Sladen, 1889

Koehler, 1923

(Koehler, 1906)

Lütken, 1871

Sladen, 1889

(Koehler, 1912)

(Koehler, 1917)

Koehler, 1920

(Philippi, 1857)

(Bell, 1881)

(Koehler, 1908)

(Koehler, 1917)

(Perrier, 1875)

(Studer, 1885)

(Koehler, 1923)

(Müller & Troschel, 1843)

Bernasconi, 1937

(Sladen, 1882)

(Sladen, 1882)

(Sladen, 1882)

Koehler, 1907

Ludwig, 1903

(Sladen, 1883)

(Ludwig, 1905)

Ludwig, 1907

(Sladen, 1889)

Sladen, 1889

Döderlein, 1927

Korovchinsky, 1976

Sladen, 1889

Koehler, 1908

Sladen, 1889

Korovchinsky, 1976

Koehler, 1907

Gray, 1847

Perrier, 1891

(Sladen, 1889)

(E. A. Smith, 1876)

(Studer, 1885)

(Koehler, 1923)

A.M. Clark, 1962

(Sladen, 1889)

(Studer, 1885)

Koehler, 1912

(Sladen, 1889)

(Koehler, 1920)

Perrier, 1891

Fisher, 1940

(Parelius, 1768)

Sladen, 1882

Koehler, 1908

Sladen, 1882

Sladen, 1882

Koehler, 1908

Koehler, 1908

Sladen, 1882

Koehler, 1908

Sladen, 1882

Sladen, 1882

Thomson, 1873

Ludwig, 1903

Sladen, 1882

Sladen, 1882

(Sladen, 1889)

Sladen, 1883

Koehler, 1907

Koehler, 1920

A.M. Clark, 1962

Sladen, 1889

Lütken, 1872

(Koehler, 1920)

E. A. Smith, 1876

(Koehler, 1912)

(Bernasconi, 1969)

Fisher, 1923

Sladen, 1889

Fisher, 1940

Koehler, 1912

Sladen, 1889

Koehler, 1920

(Say, 1825)

(Koehler, 1920)

(Ludwig, 1903)

(Ludwig, 1903)

A.M. Clark, 1962

Fisher, 1940

Fisher, 1940

(Koehler, 1920)

(Ludwig, 1903)

(Studer, 1885)

(Koehler, 1920)

(Perrier, 1881)

Fisher, 1940

(Studer, 1885)

(Studer, 1885)

(Koehler, 1911)

(Koehler, 1912)

(Ludwig, 1903)

Koehler, 1920

(Koehler, 1907)

Fisher, 1940

Fisher, 1940

(H.E.S. Clark, 1962)

Fisher, 1940

(E. A. Smith, 1876)

(Philippi, 1870)

Koehler, 1907

Koehler, 1906

(Koehler, 1912)

(Koehler, 1912)

(Koehler, 1907)

Perrier, 1885

Sladen, 1889

(Bell, 1908)

H.E.S. Clark, 1963

Sladen, 1889

Koehler, 1920

(Koehler, 1906)

Koehler, 1912

(Koehler, 1920)

(Koehler, 1912)

Sladen, 1889

Sladen, 1889

(Perrier, 1891)

(Koehler, 1907)

Perrier, 1891

Wyville Thomson, 1877

Fisher, 1940

Sladen, 1889

(Koehler, 1906)

Smith, 1876

Koehler, 1920

(Sladen, 1882)

(Sladen, 1882)

A.M. Clark, 1962

Sladen, 1882

(Sladen, 1882)

Sladen, 1882

(H.L. Clark, 1916)

Koehler, 1912

(Koehler, 1920)

Koehler, 1920

Koehler, 1907

O'Loughlin & O'Hara, 1990

(Sladen, 1889)

(Sladen, 1889)

Downey, 1971

Sladen, 1889

Sladen, 1883

Ludwig, 1907

Sladen, 1883

Koehler, 1908

Verrill, 1880

Bernasconi, 1965

Sladen, 1889

Checklist of Proposed-RAMS species

McKnight, 2006

(Farquhar, 1895)

(Muller & Troschel, 1844)

(Hutton, 1879)

(Sladen, 1889)

(Mortensen, 1925)

Müller & Troschel, 1842

(Hutton, 1872)

H.E.S. Clark, 1969

H.E.S. Clark, 1969

McKnight, 1973

(Verrill, 1894)

H.E.S. Clark, 2001

Studer, 1883

Mah, 2011

Mah & Foltz, 2014

(Gray, 1840)

Verrill, 1870

H.L. Clark, 1916

McKnight, 1973

H.L. Clark, 1916

(Perrier, 1875)

(Fell, 1953)

McKnight, 1973

(H.L. Clark, 1916)

Benham, 1909

Mah, 2011

(Sladen, 1889)

Sladen, 1889

(Sladen, 1889)

(Perrier, 1869)

Fisher, 1906

Mortensen, 1925

(Sladen, 1889)

(Farquhar, 1898)

(Perrier, 1869)

Fell, 1958

(Sladen, 1889)

(E. A. Smith, 1876)

McKnight, 1973

Wyville Thomson, 1876

(McKnight, 1973)

(Döderlein, 1927)

Macan, 1938

McKnight, 1973

A.H. Clark, 1917

(Sladen, 1889)

McKnight, 1973

Benham, 1909

(O'Loughlin, Waters & Roy, 2003)

(O'Loughlin, Waters & Roy, 2003)

(Sladen, 1889)

(Moyana & Larrain Prat, 1976)

McKnight, 1973

(Mortensen, 1925)

Janosik & Halanych, 2010

Janosik & Halanych, 2010

O'Hara, 1998

Rowe & Albertson, 1988

H.L. Clark, 1916

H.E.S. Clark, 1970

(Koehler, 1920)

(Verrill, 1867)

Mah et al. 2015

(Sladen, 1889)

Gray, 1840

Fell, 1958

McKnight, 1973

(McKnight, 1973)

McKnight, 2006

H.E.S Clark & D.G. McKnight, 2000

H.E.S. Clark, 1970

H.E.S Clark & D.G. McKnight, 2000

H.E.S Clark & D.G. McKnight, 2000

Fell, 1958

A.H. Clark, 1917

(Mortensen, 1925)

McKnight, 2006

Fell, 1958

H.E.S. Clark, 1962

Sladen, 1889

Fell, 1958

McKnight, 1973

(Sladen, 1889)

(Hutton, 1872)

H.L. Clark, 1928

Stampanato & Jangoux, 1993

Sladen, 1889

A.M. Clark, 1976

(Verrill, 1871)

McKnight, 1973

Sladen, 1889

Fisher, 1919

McKnight, 2006

Thomson, 1873

H.L. Clark, 1916

Fisher, 1906

Analysis

More than 13,000 occurrences records from 295 accepted species have been compiled within the extent of the RAMS area of interest. 198 of these species (67%) were already in the RAMS database and 97 (33%) were new to the system. After this update, the number of species in RAMS will be increased by around 50%.

The seven Orders of the Class are represented in the Southern Ocean. The  are the most speciose with 8 families, 41 genus and 87 species followed by (6 families, 30 genus, 78 species), (6 families, 22 genus, 43 species), (2 families, 6 genus, 37 species), (1 family, 4 genus, 20 species), (2 families; 9 genus; 19 species) and  (1 family, 4 genus, 2 subgenus, 11 species).

After a careful verification of the RAMS species list for we propose to address the following points. These issues have been taken into account in this paper:

and  are only described from Central America and should be removed from the RAMS list

is only described from Amsterdam and Saint-Paul Islands which are not part of the RAMS area of interest

, , , , and do not seem to be distributed in the RAMS area of interest

is only described from South America and should be removed of the RAMS list​

was originally described as  by Korovchinsky (1976)

and are source of a problem. Both genus do exist but and are the only described species. The genus name being nearly identical, it has lead to a mistake.  is an invalid name and should be deleted from RAMS and WoRMS systems

Moreover, we recommend the addition of species from our "Proposed-RAMS" checklist (i.e. species not registered in the RAMS list but present in the RAMS area of interest) to RAMS. None of these species are new to science but their austral distribution range was not properly documented (e.g. species from the Campbell Plateau are reported as New-Zealand species but are also present in the Southern Ocean, species from the French sub-Antarctic Islands, etc...). Interestingly, 22 of the 97 "non-RAMS" species are present in the Antarctic zone. Some have been described recently (e.g. and  described by Janosik and Halanych (2010);  described by Mah (2011) or  described by Mah et al. 2015) but have not been added to the RAMS.

A final comment pertains to , occurring in the RAMS Sub-Antarctic region in a location that is not actually South from the Sub-Tropical Front. This final observation shows that convenient boundaries should be used with care. However, only one species was concerned for a very wide area of interest.  presence in the RAMS checklist should be discussed by the editors from RAMS and WoRMS.

Discussion

This study highlights the fact that after ten years of effort, the work is still in progress for RAMS. The main objective of covering the Antarctic zone has generally been reached for the class but needs at this point to go through a major update by the editors. Regarding the asteroids, the secondary objective of covering the Sub-Antarctic zone lacked the impulse of the scientific community and we hope that the work presented here will fill the gaps as accurately as possible.

This approach may not bring the same results for all the taxa in the Southern Ocean. Indeed some charismatic fauna are very well known in the RAMS area of interest (e.g. marine mammals), however, we believe that the knowledge concerning the number of species present in the Southern Ocean waters might be significantly increased.

Only few mistakes were found in the existing RAMS list of and should be fixed soon after getting in contact with the editors. The new updated checklist of species will be available through the RAMS website (http://www.marinespecies.org/rams) in early 2016. A way to improve the general system, with the sea stars for model is also in development.

Recent work using genetics on  species (Janosik and Halanych 2010) highlights the fact that diversity might be higher than expected even in well-studied areas. There is also a lack of ressources for identification and taxonomic work leading to redundant mistakes. In this context, the creation of a digital library, hotlinked with the RAMS and compiling original descriptions, literature materials and DNA barcoding informations for each species will bring the RAMS a step ahead and provide a vital tool for future taxonomic and biogeographic work. Perspectives also include an illustrative determination key using a polytomic approach and the creation of interactive Antarctic Field Guides (http://afg.biodiversity.aq) on the http://www.biodiversity.aq platform (Van de Putte et al. 2015) in order to help the scientific community with the identification process and to enhance data availability.

We believe that the homogenization of available data for all taxa will result in a better understanding of the Southern Ocean and its biogeography, especially in the Sub-Antarctic zone.