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| Umbellapathes litocrada Opresko & Wagner, 2020 Photos courtesy of NOAA Office of Ocean Exploration and Research. |
Abstract
Three new species of antipatharian corals are described from deep-sea (677–2,821 m) seamounts and ridges in the North Pacific, including Antipathes sylospongia, Alternatipathes venusta, and Umbellapathes litocrada. Most of the material for these descriptions was collected on expeditions aboard NOAA Ship Okeanos Explorer that were undertaken as part of the Campaign to Address Pacific Monument Science, Technology, and Ocean Needs (CAPSTONE). One of the main goals of CAPSTONE was to characterize the deep-sea fauna in protected waters of the U.S. Pacific, as well as in the Prime Crust Zone, the area with the highest known concentration of commercially valuable deep-sea minerals in the Pacific. Species descriptions and distribution data are supplemented with in situ photo records, including those from deep-sea exploration programs that have operated in the North Pacific in addition to CAPSTONE, namely the Hawaii Undersea Research Laboratory (HURL), the Ocean Exploration Trust (OET), and the Monterey Bay Aquarium Research Institute (MBARI).
Keywords: Cnidaria; Black corals; morphology; taxonomy; Antipathidae, Schizopathidae, Hawaii, Johnston Atoll, new species
Order Antipatharia Milne Edwards, 1857
Family Antipathidae Ehrenberg, 1834
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| Antipathes sylospongia sp. nov., in situ photographs: A. holotype; B. paratype; C. HURL-P4-228-Spec. 2; D. colony photographed at 1,357 m off Lisianski (specimen not collected); E. Close-up in situ photograph of the paratype; F. Close-up photograph of colony at 1,800 m at West Northampton Seamount specimen not collected). Photos courtesy of NOAA Office of Ocean Exploration and Research. |
Genus Antipathes Pallas, 1766
Antipathes sylospongia sp. nov.
Diagnosis. Colonies found in association with glass sponges (Fig. 1); to date only recorded growing on Farrea
occa and an unidentified sponge in the family Tretodictyidae. Corallum loosely branched, without a noticeable main
stem or major branches. Branches very thin, extending out in all directions. End-branchlets small, mostly less than
2 cm, varying distances apart; tending to be arranged bilaterally along individual branches; but the arrangement can
be quite irregular, in some places alternating, and often in subopposite pairs. Spines small, triangular in lateral view,
with rounded apex; polypar spines up to 0.03 mm, abpolypar spines 0.01 to 0.02 mm. Polyps mostly about 1.5 mm
in transverse diameter (maximum about 2 mm); arranged uniserially with 5 polyps per cm.
Etymology. The species name “sylospongia” is derived from the Greek prefix “syl” meaning “with”, the connecting vowel “o” and “spongia” for the sponge hosts. To date, all known records of this species are in strict association with hexactinellid sponge hosts, either Farrea occa or an unidentified species in the family Tretodictyidae.
Distribution. Currently only known from the Musician Seamounts and the Northwestern Hawaiian Islands
between Nihoa and Lisianski at depths ranging between 677–1,800 m (Fig. 5).
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| Antipathes sylospongia sp. nov., in situ. colony photographed at 1,357 m off Lisianski (specimen not collected). Photo courtesy of NOAA Office of Ocean Exploration and Research. |
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| In situ photograph of Alternatipathes venusta sp. nov. holotype (USNM 1404492) photographed near McCall Seamount at 2,638 m. Photo courtesy of NOAA Office of Ocean Exploration and Research. |
Family Schizopathidae Brook, 1889
Alternatipathes Molodtsova and Opresko, 2017
Alternatipathes venusta sp. nov.
Diagnosis. Colony attached, monopodial, unbranched, and pinnulate. Pinnules simple, arranged alternately in two
lateral rows along upper part of stem. Lower unpinnulated section of the stem up to two times longer than upper
pinnulated section. Pinnules generally decreasing in length proximally (>13 cm) to distally (~3 cm) in a colony with a 17 cm long pinnulated section. Pinnules 4–6 mm apart on either side of axis; nine to 11 pinnules (total for both
rows) per 3 cm. Polypar spines on pinnules, conical, smooth, acute, and up to 0.22 mm tall; a few are bifurcated.
Abpolypar spines short, triangular, up to 0.08 mm tall. Five to six rows of spines visible in lateral view; with 4 spines
per mm within each row on polypar side; 3–4 spines per mm on abpolypar side. Polyps about 5 mm in transverse
diameter, with 2 polyps per cm.
Etymology. From the Latin “venusta” meaning beautiful.
Distribution. Currently only known from the Hawaiian Islands and Gorda Ridge at depths ranging between
2,638–2,821 m (Fig. 8).
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| Umbellapathes litocrada sp. nov. holotype photographed in situ on Hutchinson Seamount at 1,529 m. Photo courtesy of NOAA Office of Ocean Exploration and Research. |
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| FIGURE 12. In situ photographs of colonies presumed to be Umbellapathes litocrada sp. nov. (specimens were not collected): A. colony on Hutchinson seamount at 1,504 m; B. colony on unnamed seamount north of Johnston Atoll at 1,940 m; C. colony on Rapano Ridge at 1,973 m. D. colony on Naifeh Seamount at 1839. Photos courtesy of NOAA Office of Ocean Exploration and Research (A–B) and Ocean Exploration Trust (C–D). |
Umbellapathes Opresko, 2005
Umbellapathes litocrada sp. nov.
Diagnosis. Corallum monopodial, branched and pinnulate. Stem consisting of long lower unpinnulated section
(stalk) and upper distal section with simple bilateral primary pinnules some of which develop into branches showing same pinnulation pattern as stem, and which together form a discoidally shaped crown. Secondary pinnules not
present on primary pinnules of stem or branches. Branches developing mainly from basal-most pinnules on stem
and a varying number of more distal ones. Corallum has up to three orders of branches. Pinnules on stem generally
arranged alternately in two anterolateral to lateral rows. Pinnules not uniform in length; longest ones often in middle
or on distal part of branch. Pinnular density 9–11 per 3 cm. Spines on pinnules short, triangular to semispherical
in shape. Polypar spines up to 0.08 mm tall from midpoint of base to apex. Spines arranged in very irregular axial rows, five or six rows visible in lateral view, with about 4 spines per mm in each row. Polyps 3–4.5 mm in transverse
diameter; with 2 to 3 polyps per cm.
Etymology. From the Greek “litos” meaning “simple” and “crada” meaning “branch”, referring to the fact that
the pinnules are not subpinnulate, as in U. helioanthes.
Distribution. Currently only known from the Hawaiian Islands, the Musician Seamounts and seamounts near Johnston Atoll at depths ranging between 1,504–2,413 m (Fig. 13).
Dennis M. Opresko and Daniel Wagner. 2020. New Species of Black Corals (Cnidaria: Anthozoa: Antipatharia) from Deep-sea Seamounts and Ridges in the North Pacific. Zootaxa. 4868(4); 543–559. DOI: 10.11646/zootaxa.4868.4.5
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