| 释义 |
acritarch Palæont.|ˈækrɪtɑːk|
[f. Gr. ἄκριτ-ος uncertain + ἀρχή origin.]
Any of a group of unicellular microfossils of uncertain affinity having hollow, organic tests.
1963W. R. Evitt in Proc. Nat. Acad. Sci. XLIX. 158 A proposal for a new informal group of microfossils of organic composition and unknown affinity to be known as acritarchs. Ibid. 300 Left behind by this transfer is a ‘residue’ of forms of unknown affinities for which the name Hystrichosphaerida is no longer appropriate. It is for this ‘residue’ that I propose the name acritarchs... The name chosen implies no affinity with any other organisms and is not derived from the name of any taxon included in the group. 1970R. M. Black Elements Palaeont. xix. 299 Acritarchs are included here along with algae since they most nearly resemble cysts or vegetative stages in the life cycle of certain algae..; but there seems some possibility that a number will eventually be identified otherwise. 1979Nature 8 Feb. 464/2 The first cycle was governed by organic-walled plankton (acritarchs, green and blue-green algae), whereas the second cycle was dominated by calcareous nannoplankton (coccolithophorids, dinoflagellates). |