mesosaurn.
/ˈmɛsə(ʊ)sɔː/, U.S. /ˈmɛzəˌsɔr/; see also meso- comb. form. Palaeontology.
A small, extinct aquatic reptile of the genus Mesosaurus or order Mesosauria, of the early Permian period, having an elongated body, flattened tail, and a long narrow snout with numerous pointed teeth.
ΚΠ
1889 Philos. Trans. 1888 (Royal Soc.) B. 179 105 The mode of articulation of the ribs in Mesosaurs is difficult.
1909 Geol. Mag. 6 219 From some form like this was developed the Icthyosaurs, the Mesosaurs, and the other aquatic forms.
1933 A. S. Romer Vertebr. Paleontol. vii. 142 In ichthysaurs the hind legs were markedly reduced rather than enlarged as in mesosaurs.
1956 A. S. Romer Osteol. Reptiles ii. 473 The mesosaurs..are associated with the synapsid orders.
1973 E. H. Colbert Wandering Lands & Animals (1974) iv. 112 A few other lines of evolution also disappeared at or before the close of Permian time, such as..the mesosaurs of South Africa and Brazil.
1998 Britannica Online (Version 98.2) Fossil mesosaurs occur only in South African and South American freshwater deposits.
This is a new entry (OED Third Edition, September 2001; most recently modified version published online March 2022).
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