Scolanthus celticus Gusmão & Qu & Burke & Rodríguez 2020, sp. nov.
Creators: name: Gusmão, Luciana C.
name: Qu, Cherie
name: Burke, Sadie L.
name: Rodríguez, Estefanía
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Anthozoa
Actiniaria
Edwardsiidae
Scolanthus
Scolanthus celticus

description: Scolanthus celticus, sp. nov.
Figures 5–7, table 1
MATERIAL: Holotype AMNH _ IZC 331453; Locality: Ireland, Whittard Canyon, 48°42.534′ N, 10°33.642′ W, collected 11 June 2014, by R / V Celtic Explorer, CE 14009, event 9, gear ROV (1130 m). Paratypes AMNH _ IZC 331454 (2 specimens), sampled at the same site of the holotype. Additional material. AMNH _ IZC 331455 (1 specimen), sampled at the same site of the holotype. Material examined for comparison: Scolanthus crypticus Brandão, Gusmão, Gomes, 2019, MNRJ 8685 (8 specimens; paratypes); Locality: Brazil, São Paulo, offshore Ubatuba, 23°34′ S, 44°48′ W, collected 22 October 1986 (40 m).
DIAGNOSIS: Scolanthus with nemathybomes single or clustered, largely sunken into mesoglea protruding only a little in epidermis. Periderm very thick, rusty brown, deciduous. Basitrichs of nemathybomes 42.0–58.4 × 3.8–5.6 µm. Retractor strong, elongated, diffuse-circumscribed, with numerous processes (23–33) and easily recognizable pennon. Parietal muscle small, ovoid, and much smaller than retractor muscle. With p -mastigophores A in filament.
EXTERNAL ANATOMY (fig. 5): All specimens elongate but stout, robust, wider proximally than distally, 5–10 mm in diameter, and 14–24 mm in height. Proximal end rounded, externally differentiated from rest of column but not true physa (fig. 5A, B); body divided in aboral end, scapus, scapulus, and capitulum. All preserved specimens with distal column and oral disc retracted, including part of scapus, scapulus, and capitulum; tentacles not visible (fig. 5A). Periderm thick, rusty brown, tightly adherent, deciduous, covering column and nemathybomes from distal scapus to proximal end (fig. 5A, B). Nemathybomes conspicuous, irregularly scattered on body (fig. 5B, C), single or compound, more aggregated on proximal end (fig. 5B) due to contraction of body. Sixteen small tentacles, arranged in two cycles, presumably all of same size; tentacle length to 3 mm.
INTERNAL ANATOMY AND HISTOLOGY (fig. 6): Epidermis of entire body covered by thick periderm and nemathybomes (fig. 6A, E). Nemathybomes large, to 247.0 × 146.6 µm, simple or compound, sunken into mesoglea, but protruding into epidermis (fig. 6B, C). Longitudinal muscles of tentacles ectodermal (fig. 6D). Physa not histologically differentiated from scapus; without terminal pore. Actinopharynx short, up to 1.5 mm, occupying less than one-third of body length, highly folded. No differentiated siphonoglyph.
Mesenterial arrangement as typical for edwardsiids: eight macrocnemes span length of body, from distal column (fig. 6E) to midcolumn (fig. 6F, G); eight microcnemes only in distalmost column, at bases of tentacles (not shown). Retractor and parietal muscles both well developed, strong (fig. 6F, H). Retractor muscle of macrocnemes strong, circumscribed to somewhat diffuse, with easily recognizable pennon (fig. 6H). Retractor with numerous processes (23–33), tightly spaced, variable in height and degree of ramification, more branched at the pennon (fig. 6H). Parietal muscle small, weak, trianguloid, with longer, branched lamellae closer to body wall; central lamella thicker than side branches (fig. 6I). Specimens examined (holotype and paratype AMNH_IZC 331454) with spermatic cysts (fig. 6J), length 45.2–114.3 µm; species inferred to be gonochoric.
CNIDOM (fig. 7): Spirocysts, basitrichs, p -mastigophores A. See figure 7 and table 1 for size and distribution.
DISTRIBUTION AND NATURAL HISTORY: The four specimens were collected in a single collection site in the Whittard Canyon approximately 450 Km from the SW coast of Ireland, North Atlantic, at 1130 m depth. Scolanthus celticus was collected less than 30 km from the type locality of S. shrimp, suggesting a pattern of sympatry common among edwardsiids (Daly and Ljubenkov, 2008).
ETYMOLOGY: The specific name celticus honors the Celtic Explorer, a multipurpose research vessel operated by the Marine Institute in Galway, Ireland, which collected specimens of the new species.
description: Published as part of Gusmão, Luciana C., Qu, Cherie, Burke, Sadie L. & Rodríguez, Estefanía, 2020, Two new deep-sea species of burrowing anemones (Cnidaria: Actiniaria: Edwardsiidae) from Whittard Canyon off the southwestern coast of Ireland, pp. 1-25 in American Museum Novitates 2020 (3945) on pages 11-12, DOI: 10.1206/3945.1, http://zenodo.org/record/4598761