Cladaster rudis Verrill 1899

Mah, Christopher L., 2020, New species, occurrence records and observations of predation by deep-sea Asteroidea (Echinodermata) from the North Atlantic by NOAA ship Okeanos Explorer, Zootaxa 4766 (2), pp. 201-260 : 219

Cladaster rudis Verrill 1899

Figure 8 A–D

This species was identified based on its triangular arms and coarse granules covering the abactinal and marginal plate surfaces, superomarginals abutted over the mid radius on each arm, the large single subambulacral spine and the pedicellariae type present on the actinal surface.

The sample collected was obtained from a region near the type locality and was morphologically very similar in terms of the abactinal and marginal surface granulation and plate and arm plate morphology. The specimen had much rounder granules on the actinal surface versus the holotype which had more pointed and conical granules on the surface. Pedicellariae also seemed to be more abundant on the specimen mentioned herein.

Feeding Observations

On three of the four observations that this species was observed, it was positioned vertically on a small branched Lophelia colony upon which it was apparently feeding ( Fig. 8A ). Polyps from the colony were withdrawn with most of the colony seemingly lifeless. One of the Stetson Mesa West observations observed a Cladaster present on a laterally positioned Lophelia colony with its disk and arms arched around it. This represents the first in situ feeding observation of Cladaster rudis .

Occurrence: Off Florida, Stetson Mesa North and West, Blake Plateau, Yucatan Channel. 150– 900 m.

Images Examined

Stetson Mesa North, North Atlantic 30.40337, -79.59817, 787 m.

EX1806_IMG_20180620T 151009 Z_ROVHD.jpg

Stetson Mesa West 29.859987, -79.455657, 767 m.

EX1907_IMG_20191103T205656Z_ROVHD.jpg

Stetson Mesa West 29.861274, -79.45494, 785 m.

EX1907_IMG_20191103T185505Z_ROVHD.jpg

Material Examined

USNM 1607547 Stetson Mesa Mound Field One, 30.399, -79.2757, 824 m, Coll. ROV Deep Discoverer, NOAA Ship Okeanos Explorer , EX 1907. 4 Nov. 2019. 1 wet spec. R=1.9 r=1.0. EX1907_IMG_20191104T175744Z_ ROVHD.jpg

Figures

FIGURE 8. Cladaster rudis, USNM 160757 A. In situ feeding observation of Cladaster feeding on Lophelia coral. B. Abactinal surface. C. Actinal surface. D. Actinal intermediae region, showing three pedicellariae (indicated with arrows).