Nidalia occidentalis Gray, 1835

Devictor, Susan T. & Morton, Steve L., 2010, Identification guide to the shallow water (0 - 200 m) octocorals of the South Atlantic Bight 2599, Zootaxa 2599 (1), pp. 1-62 : 31-32

Nidalia occidentalis Gray, 1835

( Figure 30C,D )

Nidalia occidentalis Gray 1835:60 .— Deichmann 1936: 56; Plate 1 fig. 3[sic. 5]; Plate 4 figs. 1–3.— Utinomi 1958:102; Figs. 1–3 .— Bayer 1961:53; Figs. 9h , 10a–c .— Verseveldt 1978:45.— Verseveldt and Bayer 1988:59; Figs. 42e–g , 45 , 47b , 52, 53. — Cairns et al. 2002:33.

Material examined. SERTC S 1384, 63 m, off Anastasia Island , FL, August 30, 2004 . S 2325, 92 m, off Charleston , South Carolina, April 12, 1974 . S 2788, 60 m, off Anastasia Island , Florida, August 31, 2004 .

Remarks. Nidalia occidentalis is easily distinguishable from other octocorals in the SAB by its stiff, barren stalk and capitate head bearing the monomorphic polyps and conical calyces. The stalk bears large (up to 1 mm), slightly curved, tuberculated spindles while the anthocodiae contain smaller needle-like rods in a collaret and points arrangement, and small flat platelets. The large spindles are six times longer than wide, a feature that distinguishes N. occidentalis from N. rigida , which bears thicker spindles. In life, one SERTC Nidalia occidentalis specimen had an orange stalk and red terminus bearing white polyps. In the preserved state the colors are slightly duller. The examined specimens reach 20 mm in length.

Atlantic distribution: North Carolina to French Guiana, Gulf of Mexico, Caribbean, 37–440 m (one record off Venezuela indicates collection from 914 m) ( Deichmann, 1936; Bayer 1961; Verseveldt 1978; NMNH collections; SERTC collection).

Figures

FIGURE 1. The South Atlantic Bight, which includes coastal waters between Cape Hatteras and Cape Canaveral, USA. The 200 m isobath is shown.

FIGURE 2. Branching colony forms; a) dichotomous (Iciligorgia schrammi); b) monopodial (Telesto sp.); c) whip-like branches (Leptogorgia virgulata); d) rod-like branches (Titanideum frauenfeldii); e) open, irregularly pinnate (Muricea pendula) f) planar (Leptogorgia hebes); g) lobed, with clusters of polyps (Pseudodrifa nigra).

FIGURE 3. Unbranched colony forms; a) flagelliform (whip-like) (Leptogorgia setacea); b) capitate (Nidalia occidentalis); c) foliose (Renilla reniformis) d) club-like (Sclerobelemnon theseus); e) pen-like (Virgularia presbytes); f) stoloniferous (Scleranthelia rugosa var. rugosa).

FIGURE 9. a) Pseudodrifa nigra, basal disc indicated; b) holdfast of Muricea pendula; c) encrusting colony of Scleranthelia rugosa (from Bayer 1981a).

FIGURE 10. a) Sclerobelemnon theseus peduncle indicated; b) Renilla reniformis, peduncle indicated; c) Virgularia presbytes, leaf-like structures indicated; d) Stylatula elegans, showing two polyp leaves (modified from Bayer, 1958).

FIGURE 30. A, Pseudodrifa nigra (USNM 55234) sclerites; a, b) foliated clubs from polyp wall; c–g) sclerites from stalk (scale bar = 0.05 mm); B, Pseudodrifa nigra (live specimen), base width approximately 27 mm; C, Nidalia occidentalis (live specimen, S1384), height approximately 20 mm; D, Nidalia occidentalis (S1384) sclerites; a, b) large spindles from capitulum; c, d) small spindles from capitulum; e–g) small platelets from polyp; h–j) spindles from polyp (scale bar for a, b = 0.2 mm; c, d, h–j = 0.1 mm; e–g = 0.02 mm).

FIGURE 42. Leptogorgia hebes: A, sclerites (S1863); a–c) capstans from coenenchyme; d, e) flat anthocodial rods (scale bar = 0.02 mm); B, stem and expanded polyps; C, colony morphology (S430, preserved specimen; height approximately 15 cm).

FIGURE 45. Leptogorgia virgulata: A, coenenchymal sclerites (S2713) (disc spindles and anthocodial rods not shown; scale bar = 0.05 mm); B, close-up of branch (live specimen), showing polyp expansion (stem width approximately 3 mm); C, colony in situ; D, branching arrangement (preserved specimen); E, polyps (live specimen).

FIGURE 47. Renilla reniformis: A, live specimen (S427), whole colony (diameter approximately 22 mm); B, frond with expanded polyps, showing sclerites.