A marine invertebrate of the phylum "Hemichordata"; an acorn worm.
- ‘Molecular phylogenies have suggested that hemichordates are in fact a sister lineage to the echinoderms.’
- ‘The molecular phylogeny does agree in one respect with the morphological one in that there are close similarities between the larvae of hemichordates (acorn worms and pterobranchs) and some echinoderms.’
- ‘Unfortunately, a change in the genetic code of the mitochondrial genome in both enteropneusts and echinoderms strongly rejects chordate affinities of the hemichordates.’
- ‘Size comparisons between living and extinct hemichordate zooids are not conclusive evidence, however, as it is easy to imagine a small, hypothetical, zooid that possessed multiple tentaculated arms.’
- ‘We chordates are deuterostomes, as are echinoderms, some marine worms called hemichordates, and the urochordates, or sea squirts.’
Relating to or denoting hemichordates.
- ‘Evidence for the hemichordate affinity of the extinct graptolites has been steadily amassing.’
- ‘The hemichordate sequences always contained considerable support for both hypotheses.’
- ‘There are two classes of hemichordate, the pterobranchs and the enteropneusts, which differ greatly in appearance and lifestyle.’
- ‘Unfortunately there are no living fenestrate hemichordate species.’
- ‘They lack two others, the notochord and post-anal tail, hence the name hemichordate.’