agnathan

English

Agnathans, such as this lamprey, are distinguished by the lack of a jaw.

From Agnatha, from Ancient Greek ἀ- (a-, “without”) + γνάθος (gnáthos, “jaw”)

agnathan (comparative more agnathan, superlative most agnathan)

(zoology) Belonging or pertaining to the superclass Agnatha, the jawless vertebrates.
- 2005, Tim Haines and Paul Chambers, The Complete Guide to Prehistoric Life, BBC Books, page 20:
  Haikouichthys is one of three species of jawless (or agnathan) fish to be found in the Early Cambrian period.

agnathan (plural agnathans)

(zoology) A member of the superclass Agnatha of jawless vertebrates.
- 1956, D. R. Newth, "On the Neural Crest of the Lamprey Embryo", Journal of Embryology and Experimental Morphology, volume 4, page 358:
  Thus should the cranial neural crest in cyclostomes prove to be non-skeletogenous this might be a reflection either of its own primitiveness or of the different evolutionary origins and morphological status of the visceral skeleton in agnathans and gnathostomes.
- 1992, Peter J. Hanley et al., "Hagfish Humoral Defense Protein Exhibits Structural and Functional Homology with Mammalian Complement Components", Proceedings of the National Academy of Sciences, volume 89, page 7910:
  The hagfish is an agnathan, a modern representative of the earliest evolved group of vertebrates, the ostracoderms or jawless fishes, which arose prior to the ancient placoderms (3).

member of the superclass Agnatha of jawless vertebrates