different between agnathan vs agnathia

English

Etymology

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

Pronunciation

• enPR: ?g?n?-th?n, IPA^(key): /?æ?.n???n/, /æ??næ.??n/

Adjective

agnathan (comparative more agnathan, superlative most agnathan)

1. (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.

Noun

agnathan (plural agnathans)

1. (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).

Synonyms

• agnath
• agnatha

Hypernyms

• vertebrate

Hyponyms

• cyclostome
• ostracoderm

Coordinate terms

• gnathostome

Translations

English

Etymology

Ancient Greek ?- (a-, “without”) + ?????? (gnáthos, “jaw”) +? -ia.

Pronunciation

• enPR: ?g-n??thi-?, IPA^(key): /æ??ne?.?i.?/

Noun

agnathia (uncountable)

1. (pathology) A birth defect in which the mandible is missing.
   • 1831, William West, translation of Gabriel Andral, A Treatise on Pathological Anatomy, Hodges and Smith, volume 2, page 283:

     When there is agnathia, instead of the inferior maxillary bone we find nothing but a kind of tubercle formed of skin, cellular tissue, fat, and some few muscular fibres.

   • 1907, Francis Delafield and T. Mitchell Prudden, A Text-Book of Pathology, eighth edition, William Wood, page 304

     The lower jaw may be absent (agnathia).

   • 2006, Mark I. Evans et al., Prenatal Diagnosis, McGraw-Hill, ?ISBN, page 240:

     As such, it is often accompanied by agnathia, a congenital absence of the mandible[…].

Related terms

• agnath
• agnatha
• agnathan
• agnathous

Translations

References

• agnathia in The Century Dictionary, New York, N.Y.: The Century Co., 1911.