Antipatharia, Milne-Edwards & Haime, 1857

Lima, Manuela M., Cordeiro, Ralf T. S. & Perez, Carlos D., 2019, Black Corals (Anthozoa: Antipatharia) from the Southwestern Atlantic, Zootaxa 4692 (1), pp. 1-67 : 62-63

Artifical key to South Atlantic Antipatharians

1A: Colony unbranched (filiform)............................................................................ 2

1B: Colony monopodial and pinnulate or branched, with or without pinnules......................................... 5

2A: Polyps in more than one row............................................................ Cirrhipathes secchini

2B: Polyps in one single row................................................................................ 3

3A: Polypar spines up to 0.18 mm in height................................................. Stichopathes occidentalis

3B: Polypar spines more than 0.18 mm in height................................................................ 4

4A: Spines up to 0.24 mm in height........................................................... Stichopathes spiessi

4B: Spines up to 0.34 mm in height........................................................ Stichopathes paucispina

5A: Corallum not pinnulated................................................................................ 6

5B: Corallum pinnulated................................................................................... 9

6A: Spines anisomorphic.................................................................. Acanthopathes humilis

6B: Spines isomorphic.................................................................................... 7

7A: Spines on the entire corallum............................................................................ 8

7B: Spines only on terminal branchlets....................................................... Leiopathes glaberrima

8A: Corallum branching in one plane, usually fan-shaped.......................................... Antipathes atlantica

8B: Corallum branching in more than one plane; broom like, with long ascending branches................ Antipathes furcata

9A: Polyps 2 mm or more in transverse diameter............................................................... 10

9B: Polyps usually less than 2 mm in transverse diameter........................................................ 23

10A: Spines simple, smooth, deltoid, conical and acicular in lateral view; polyps without secondary mesenteries............. 11

10B: Spines simple or with multiple bifurcations, triangular, laterally compressed; polyps with six primary and four secondary mesenteries........................................................................................... 14

11A: Primary pinnules irregularly arranged, sometimes in clusters of three............................ Cladopathes plumosa

11B: Primary pinnules in four or more regular rows............................................................. 12

12A: Primary pinnules in four rows........................................................ Trissopathes cf. tristicha

12B: Primary pinnules in six rows........................................................................... 13

13A: Around two secondary pinnules per posterior primary; 22 to 33 primary pinnules per centimeter...................................................................................................... Chrysopathes micracantha

13B: One secondary pinnule per posterior primary; 18 to 21 primary pinnules per centimeter........... Chrysopathes oligocrada

14A: Polyps reaching 2–3 mm in diameter..................................................................... 15

14B: Polyps 3 mm or more in diameter....................................................................... 17

15A: Corallum branched to the third or fourth order.................................................. Taxipathes recta

15B: Corallum monopodial or sparsely branched................................................................ 16

16A: Spines up to 0.07 mm in height........................................................ Parantipathes laricides

16B: Spines up to 0.20 mm in height...................................................... Parantipathes helicosticha

17A: Pinnules in two rows, subpinnulated................................................. Dendrobathypathes grandis

17B: Pinnules in two rows, simple........................................................................... 18

18A: Corallum branched................................................................................... 19

18B: Corallum unbranched................................................................................. 20

19A: Pinnules short, up to 1 cm in length...................................................... Stauropathes punctata

19B: Pinnules long, more than 3 cm long.......................................................... Telopathes magna

20A: Corallum not attached................................................................... Schizopathes crassa

20B: Corallum attached.................................................................................... 21

21A: Pinnules decreasing in size distally toward the corallum apex............................... Alternatipathes alternata

21B: Pinnules longest in the middle of the corallum............................................................. 22

22A: Spines up to 0.26 mm in height......................................................... Bathypathes galatheae

22B: Spines usually less than 0.1 mm in height.................................................... Bathypathes patula

23A: Pinnules and subpinnules in rows or pairs................................................................. 24

23B: Pinnules and subpinnules in verticils..................................................................... 32

24A: Pinnules subpinnulated................................................................................ 25

24B: Pinnules simple...................................................................................... 30

25A: Colony densely branched................................................................ Tanacetipathes hirta

25B: Colony monopodial or sparsely ramified.................................................................. 26

26A: Secondary pinnules up to 47 mm long............................................... Tanacetipathes longipinnula

26B: Secondary pinnules usually up to 22 mm long.............................................................. 27

27A: Posterior primary pinnules bearing up to 42 secondary pinnules............................ Tanacetipathes thalassoros

27B: Posterior primary pinnules bearing up to 18 secondary pinnules................................................ 28

28A: Posterior primary pinnules bearing 8 to 10 secondary pinnules................................ Tanacetipathes thamnea

28B: Posterior primary pinnules bearing less than 7 secondary pinnules.............................................. 29

29A: Posterior primary pinnules bearing 3 to 7 secondary...................................... Tanacetipathes tanacetum

29B: Posterior primary pinnules bearing less than 3 secondary................................. Tanacetipathes barbadensis

30A: Pinnules/branchlets in one to four irregular rows........................................... Antipathella wollastoni

30B: Pinnules in two regular rows........................................................................... 31

31A: Distance between pinnules in a same row 1.6–2.0 mm....................................... Plumapathes pennacea 31B: Distance between pinnules in a same row 2–4 mm ......................................... Plumapathes fernandezi 32A: Corallum branched, mainly from near the base........................................ Triadopathes cf. triadocrada 32B: Corallum monopodial, rarely branched................................................................... 33 33A: Subpinnules rarely covering the “worm run”.............................................. Stylopathes columnaris 33B: Subpinnules always covering the “worm run”............................................. Stylopathes adinocrada

Distribution of the Antipatharia order in the South Atlantic

There are currently 97 antipatharian species recorded from the Atlantic Ocean (Supplementary file), with representatives of all seven families. Of this total, approximately 59% (~ 57 spp.) of the species occur in the western North Atlantic, this being the region that holds the largest number of records (Supplementary file). About 58 species of the order are endemic to the Atlantic. Five genera are unique to this region: Distichopathes Opresko, 2004 , and Elatopathes Opresko, 2004 , in the family Aphanipathidae ; Tanacetipathes Opresko, 2001 , in the family Myriopathidae ; and Taxipathes Brook, 1889 and Telopathes MacIsaac & Best 2013 ; in the family Schizopathidae .

Of the 97 black coral species recorded for the entire Atlantic, three species (about 3%) are endemic to the southwestern region and none are endemic to the southeastern region so far. The southeastern Atlantic has only one black coral record, Parantipathes helicosticha Opresko, 1999 , from Valdivia seamount, which forms part of the Walvis Ridge ( Molodtsova & Pasternak, 2005).

As of 2009 approximately 40 black coral species (16% of the diversity of antipatharians species currently known worldwide) were recorded from the Gulf of Mexico (data compiled in this paper; Opresko, 2009). The Caribbean Sea, being one of the regions with the best documented antipatharian faunas of the world ( Opresko, 2009; Wagner et al., 2015), has 57 recorded species.

The major biogeographic barriers which were thought to separate the shallow-water fauna of the Caribbean Sea and the northeastern part of South America from the rest of the Atlantic coast of South America are the mouth of the Amazon River and the mouth of the Orinoco River. However, Cordeiro et al. (2015) recently verified the existence of a mesophotic reef between 18 and 125 m deep at 15 km off the mouth of the Amazon River, and recorded 38 coral species for this region, including a species in the antipatharian genus Cirrhipathes . Thus, corals occurring below 30 m do not suffer from the direct influence of the Amazon plume ( Cordeiro et al., 2015), thereby enabling faunal connectivity between the Caribbean Sea and the South Atlantic.

Approximately 25 black coral species occur in Brazil (including records documented in the present work). Of these, 15 are shared with the Caribbean Sea. The best documented region in the western South Atlantic corresponds to the region between 13° and 22° S ( Loiola & Castro, 2001; Loiola & Castro, 2005; Loiola, 2007; Cordeiro et al., 2012). Although there is a record of the species Tanacetipathes tanacetum ( Pourtalès, 1880) for the Parcel of Manuel Luís, the northern region of Brazil still represents a great gap in knowledge.

This study contains the first description of the black coral fauna of the Rio Grande Rise, and identifies nine species for the region. However, only Leiopathes glaberrima ( Esper, 1788) is shared with the Brazilian continental margin. Other two species [ Leiopathes glaberrima ( Esper, 1788) ; Stauropathes punctata ( Roule, 1905) ] occur in the northeastern Atlantic, while three species [ Parantipathes helicosticha Opresko, 1999 ; Parantipathes laricides Van Pesch, 1914 ; and Stichopathes paucispina Brook, 1889 ] occur in IndoPacific. Parantipathes helicosticha , orginally described from Australia and Tasmania, also has a record for the Walvis Range in the Southeast Atlantic.

In the future, more specimens collected in the Rio Grande Rise may also allow confirmation of the identification of Trissopathes tristicha ( Van Pesch, 1914) and Triadopathes triadocrada ( Opresko, 1999) for the South Atlantic. Both species were also originally described for the western Pacific, in waters adjacent to coast of Australia.

Although the invertebrate fauna of the Rio Grande Rise has just begun to be studied in this decade, the icthyofauna already recorded has a high similarity with that found in the Walvis and Madagascar Cordillera, the latter in the Indian Ocean ( Pérez et al., 2012). However, any biogeographic inference for antipatharians is still premature.