Solasteridae Viguier 1878

SOLASTERIDAE Viguier, 1878

Comments

The Solasteridae are among the most visible among Antarctic asteroids, including genera, such as Lophaster Verrill, 1878 and Paralophaster Fisher, 1940 which includes among the largest species [e.g., Lophaster gaini Koehler, 1912b up to R= 8–9 cm and Paralophaster antarcticus (Koehler, 1912a) up to R=16.0 cm] in the Southern Ocean. Solasterids, which historically included Cuenotaster until 2011, are among the more regularly documented asteroid taxa reported in monographs of Antarctic Asteroidea (e.g., Fisher 1940; Koehler 1912a, 1912b, 1920; A.M. Clark 1962; H.E.S. Clark 1963), implying they are significant members of the benthic community at high-latitudes. It is surprising that so little has been documented regarding their basic biology, including feeding habits and other ecological information, especially given that where solasterids have been studied (e.g., Solaster Forbes, 1839 in the Pacific Northwest), they are important predators, playing significant roles in community structure (Van Veldhuizen & Oakes 1981). Among Antarctic solasterids, Lophaster gaini is a predator on Antarctic scallops (Berkman 1988) and Solaster regularis is a predator on sea stars and other echinoderms (Mutschke & Mah 2009).

The Solasteridae have been most recently placed within the Valvatacea with molecular phylogenetic overviews reaffirming their relationship with the Asterinidae and related groups such as the Ganeriidae (now a subfamily) (Mah & Foltz 2011b; Mah & Fujita 2020).

Solasterids are diverse at high-latitude settings, including 11 species in four genera, Lophaster, Paralophaster, Solaster, and Crossaster (Mah 2021). Among significant changes to the Solasteridae from this region, A.M. Clark (1962) synonymized the Antarctic Myoraster Fisher 1940 with Paralophaster and Cuenotaster, historically placed within the Solasteridae was moved to the Ganeriidae based on molecular data (Mah & Foltz 2011b). All genera of Solasteridae are now known to occur widely, with occurrence of Crossaster, Lophaster, Paralophaster, and Solaster in both the northern and southern hemispheres. Paralophaster, which had previously recorded exclusively from Antarctic and adjacent regions, has been recorded from deep-sea, North Pacific settings (Mah & Fujita 2020).

Key to the Genera of High-Latitude Solasteridae

(0) Arms 5, exceptionally 6................................................................................ (1) (0’) Multiple arms (7–12)................................................................................. (2)

(1) Superomarginal plates well-developed and morphologically distinct from adjacent abactinal paxillae, present at base of inferomarginal plates................................................................. Lophaster Verrill, 1878 (1’) Superomarginal plates weakly developed, similar or indistinguishable from abactinal paxillae.... Paralophaster Fisher, 1940

(2) Abactinal skeleton reticulate, irregular with wide, open. Paxillae widely spaced with needle-like spinelets. Multiple papulae (>10 present between skin filled plates)....................................... Crossaster Müller & Troschel, 1840a

(2’) Abactinal plates more closely arranged, fenestrate. Paxillae more closely arranged with shorter spinelets. One or two papulae present within pores on abactinal skeleton.................................................. Solaster Forbes, 1839