| 释义 |
somasteroid, a. and n. Zool.|səʊˈmæstərɔɪd|
Also Somasteroid.
[ad. mod.L. Somasteroidea (W. K. Spencer 1951, in Phil. Trans. R. Soc. B. CCXXXV. 87), f. Gr. σῶµα body + mod.L. Asteroidea, name of a subclass or class of echinoderms, f. Gr. ἀστεροειδής (see asteroid a. and n.) + L. -ea, neut. pl. of -eus -eous.]
A. adj. Belonging or pertaining to the sub-class or class Somasteroidea, which belongs in the subphylum Asteroidea of star-shaped echinoderms and comprises extinct forms having broad, petal-like arms with a pinnate structure.
B. n. A somasteroid echinoderm.
1955L. H. Hyman Invertebrates IV. xv. 700 The arrangement recently adopted by palaeontologists.., according to which asteroids and ophiuroids derive from a common somasteroid..ancestor.., must be somehow wrong. 1962D. Nichols Echinoderms iii. 40 The fossilized remains of these ossicles have even been found in the earliest asteroids, the Somasteroids. 1963Phil. Trans. R. Soc. B. CCXLVI. 383 The Asterozoa, or star-shaped echinoderms, may be regarded as a natural taxon, comprising the somasteroids, asteroids and ophiuroids. 1964[see phanerozone a. (n.)]. 1979W. D. Russell-Hunter Life of Invertebrates xxxiv. 607 The smallest class, Somasteroidea, which arose in the Ordovician, was never an extensively diversified group, being relegated by many neontologists to the status of a subclass of the Asteroidea. (The living genus, Platasterias, is no longer regarded as a somasteroid.) |
