Chitonaster cataphractus Sladen 1889

• Main Author: Mah, Christopher L.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2011
• Subjects: Biodiversity; Taxonomy; Animalia; Echinodermata; Asteroidea; Valvatida; Goniasteridae; Chitonaster; Chitonaster cataphractus; South Sandwich Islands; Southern Ocean; Thurston Island
• Online Access: https://doi.org/10.5281/zenodo.6184329; http://treatment.plazi.org/id/03D28792FFCEFF9184E4178A6ED0834B

Chitonaster cataphractus Sladen, 1889 (Figure 4 A–E) Sladen, 1889: 283; A.M. Clark, 1962: 22; 1992: 250; A.M. Clark, 1993: 250 (as C. cataphractus ) Distribution. South Sandwich and Thurston Island, Ellsworth Land to 62˚26’S, 95˚44’E (type locality), 3612– 5350 m. Comments and distinctions from other species. Chitonaster cataphractus is distinguished from the other species of Chitonaster based on the single spines on each abactinal and superomarginal plate, the superomarginal and inferomarginal spines in series, the absence of pedicellariae, the elongate arms and relatively small disk (Fig. 4 A–E). Other characters, such as the relatively small abactinal plates and the absence of papulae, are shared between C. cataphractus , C. felli , and C. johannae . These all appear to be characters present in taxa collected from abyssal depths (2000–5000 m). Original type specimens and newly collected specimens of C. cataphractus show disparity between small and large sized specimens as well as the number of spines on the marginal plates. The serial spination on the superomarginals and inferomarginals is present in smaller C. cataphractus but is less distinct relative to those observed in the adults and may vary in specimens as specimen size inceases. Although morphological distinctions are clear between specimens examined, characters such as presence/absence of pedicellariae among other Goniasteridae have been shown to be variable. The boundary between C. cataphractus and C. johannae should be regarded carefully as more specimens become available. Material examined. USNM 1122198 South Sandwich Islands, 55˚05’ 35”S 25˚47’23”W, 5350 m. Coll. Moss Landing Marine Laboratories (1 dry spec. R=4.6, r=1.3); USNM 1122200 South Sandwich Islands, 55˚05’ 34.8”S 25˚ 47’ 23.28” W, 5350 m. Coll. Stacy Kim, Moss Landing (3 wet spec. R=5.4, r=1.5; R=5.5, r=1.8; R=5.7, 4=1.5), USNM 1086360 Thurston Island, Ellsworth Land, Southern Ocean. 70˚20’S, 99˚ 10’W to 70˚13’S, 98˚57’W. 3848–3980 m. (1 dry spec. R=2.0, r=0.7). Description. Body ...