Circeaster americanus (A.H. Clark 1916 )

Mah, Christopher L., 2024, Two New Taxa of Goniasteridae (Asteroidea, Echinodermata) and Noteworthy Observations of Deep-Sea Asteroidea by the NOAA Ship Okeanos Explorer in the North and Tropical Atlantic, Zootaxa 5432 (4), pp. 461-508 : 481-483

Circeaster americanus (A.H. Clark 1916)

FIGURE 8A–B , 9A–B

Clark & Downey 1992: 237; Mah 2015: 2; Garcia-Guillen et al. 2023: 231, 233

Diagnosis

Body stellate, (R/r= ~2.4 to 4.0). Granules round, scattered over abactinal disc, arm surfaces. Arm plates enlarged, bare relative to disc plates; Disc plates transition gradually to those on arm, overall disc plates similar to arm plates in overall size and shape. Superomarginal plates abutted at midline. Row of enlarged subambulacral spines present adjacent to furrow spines. Bivalve pedicellariae present on actinal and adambulacral plates.

Comments

Two clear observations of this distinctive species were observed in situ for the first time from Kuchatov Ridge ( Fig. 8A–B ) and Cachalote Guyote in the eastern Atlantic. A determination of Circeaster was clear from the images. This further confirms a significant new range occurrence for this species, which has historically been known only from the tropical western Atlantic ( Clark & Downey 1992; Halpern 1970). Garcia-Guillen et al (2023) recorded this species in the eastern Atlantic, south of the Azores. In situ observations from EX2107 extend the lower depth range of this species to 1756 m.

Occurrence

Tropical Atlantic. Florida, Louisiana, Gulf of Mexico, North Carolina and the Caribbean, including Columbia, the Grenadines, Leeward Islands, Nicaragua, Netherlands, Antilles, St. Vincent, Suriname and Venezuela. 668–1675 m.

North Atlantic. Manning Seamount. 1333 m.

New occurrence. Eastern Atlantic. South of Azores. Kurchatov Ridge and Cachalote Guyote. 1462–1756 m.

Images Observed

Kurchatov Ridge, North Atlantic (near Azores), 40.662469, -29.384747, 1756 m EX2205_IMG_20220725T122132Z_ROVHD.jpg

Kurchatov Ridge, North Atlantic, 40.663154 -29.386514, 1658 m.

EX2205_IMG_20220725T161626Z_ROVHD.jpg

Cachalote Guyote, North Atlantic (near Azores), 39.365395, -31.969577, 1462 m EX2205_IMG_20220728T150553Z_ROVHD.jpg

EX2205_IMG_20220728T150619Z_ROVHD.jpg

Million Mounds dive site, western North Atlantic, 28.538949 -79.262737, 816 m.

EX2107_IMG_20211114T163028Z_ROVHD.jpg

EX2107_IMG_20211114T163024Z_ROVHD.jpg

Figures

FIGURE 8. Circeaster americanus (Goniasteridae) New Observations, East Atlantic. A. Kuchatov Ridge, 1756 m. B. Kuchatov Ridge, 1658 m.

FIGURE 9. Circeaster americanus (Goniasteridae) A. Cachalote Guyote, 1462 m. B. Million Mounds (east coast of Florida), 816 m.