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| Distichopathes hickersonae Opresko & Brugler
in Opresko, Goldman, Johnson, ... et Brugler, 2020.
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Abstract
The continental shelf edge of the NW Gulf of Mexico supports dozens of reefs and banks, including the West and East Flower Garden Banks (FGB) and Stetson Bank that comprise the Flower Garden Banks National Marine Sanctuary (FGBNMS). Discovered by fishermen in the early 1900s, the FGBs are named after the colourful corals, sponges and algae that dominate the region. The reefs and banks are the surface expression of underlying salt domes and provide important habitat for mesophotic coral ecosystems (MCE) and deep coral communities to 300 m depth. Since 2001, FGBNMS research teams have utilized remotely operated vehicles (e.g. ‘Phantom S2’, ‘Mohawk’, ‘Yogi’) to survey and characterize benthic habitats of this region. In 2016, a Draft Environmental Impact Statement proposed the expansion of the current sanctuary boundaries to incorporate an additional 15 reefs and banks, including Elvers Bank. Antipatharians (black corals) were collected within the proposed expansion sites and analysed using morphological and molecular methods. A new species, Distichopathes hickersonae, collected at 172 m depth on Elvers Bank, is described within the family Aphanipathidae. This brings the total number of black coral species in and around the sanctuary to 14.
Keywords: Distichopathes, DNA barcoding, Flower Garden Banks National Marine Sanctuary, mesophotic coral ecosystem, scanning electron microscopytaxonomy
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| Fig. 2. Distichopathes hickersonae sp. nov., colony photographed in situ, at 172 m on Elvers Bank (specimen not collected). |
Systematics
Order ANTIPATHARIA Milne-Edwards & Haime, 1857
Family APHANIPATHIDAE Opresko, 2004
Diagnosis: Corallum sparsely to densely branched (i.e. bramble-like, bushy, broom-like or fan-shaped), or pinnulated with simple pinnules arranged in two or more rows. Spines conical; usually covered to varying degrees with conical tubercles, but may be smooth; apex of spines simple (acute or rounded), occasionally bifurcated. Polyps 0.6–3 mm in transverse diameter.
Genus Distichopathes Opresko, 2004
Antipathes, de Pourtalès, 1867: 112, 1871: 54, 1880: 118 (in part); van Pesch, 1914: 85 (in part, as subgenus Aphanipathes).
Aphanipathes Brook, 1889: 121 (in part); Opresko, 1972: 993 (in part).
Distichopathes Opresko, 2004: 235–237.
Diagnosis: Corallum monopodial, unbranched, or sparsely to densely branched; tending to be planar with overlapping branches. Stem and branches pinnulate. Pinnules simple, not subpinnulate; arranged primarily in two lateral rows, but with simple short pinnules occurring very rarely on the abpolypar side of the axis. Pinnules also arranged alternately along the stem and branches.
Type species: Distichopathes disticha Opresko, 2004.
Species assigned to Distichopathes: Three species are currently assigned to the genus, D. filix (de Pourtalès, 1867), D. disticha Opresko, 2004, and D. hickersonae sp. nov.
Distribution: Species of Distichopathes are known only from the North-western Atlantic.
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| Fig. 3. Distichopathes hickersonae sp. nov. (A) In-situ photo of holotype (USNM 1517703); (B) laboratory photo of holotype; (C) In-situ photo of paratype (USNM 1548274); (D) laboratory photo of paratype; (E) upper section of two branches of the paratype. |
Distichopathes hickersonae sp. nov. Opresko & Brugler
Diagnosis: Corallum densely branched, branches tending to lie in one plane. Stem and branches with simple bilateral pinnules. Pinnules up to 2 cm long and 0.3 mm in diameter at their base; arranged in two very regular bilateral rows, with pinnules in each row alternating with those in opposite row. Small simple pinnules occurring very rarely on the abpolypar side of the axis. Spines anisomorphic: circumpolypar spines 0.26–0.35 mm tall, interpolypar spines 0.2–0.25 mm, the hypostomal spines 0.1–0.14 mm, and the abpolypar spines 0.1–0.18 mm. Polyps small, 0.65–0.8 mm in transverse diameter and are placed in a single series on one side of the pinnules, with 8–10 polyps per cm.
Etymology: Named in recognition of Emma L. Hickerson (NOAA's FGBNMS Research Coordinator). Since 2005, Emma has generously been inviting co-authors DMO and MRB, as well as underrepresented minority undergraduates from CUNY, to the FGBNMS to survey and collect black corals. These research cruises aboard the MV ‘Spree’ and RV ‘Manta’ have resulted in the discovery of a number of new species of antipatharian corals.
Distribution: Known only from the north-western Gulf of Mexico at 172 m depth.
Dennis M. Opresko, Samantha L. Goldman, Raven Johnson, Katherine Parra, Marissa Nuttall, G.P. Schmahl and Mercer R. Brugler. 2020. Morphological and Molecular Characterization of A New Species of Black Coral from Elvers Bank, north-western Gulf of Mexico (Cnidaria: Anthozoa: Hexacorallia: Antipatharia: Aphanipathidae: Distichopathes). Journal of the Marine Biological Association of the United Kingdom. 100(4); 559-566. DOI: 10.1017/S002531542000051X
