Paleontology. Primitive jawed fishes had teeth of their own design.
نویسنده
چکیده
منابع مشابه
Number and arrangement of extraocular muscles in primitive gnathostomes: evidence from extinct placoderm fishes.
Exceptional braincase preservation in some Devonian placoderm fishes permits interpretation of muscles and cranial nerves controlling eye movement. Placoderms are the only jawed vertebrates with anterior/posterior obliques as in the jawless lamprey, but with the same function as the superior/inferior obliques of other gnathostomes. Evidence of up to seven extraocular muscles suggests that this ...
متن کاملEarly Jurassic diversification of pycnodontiform fishes (Actinopterygii, Neopterygii) after the end-Triassic extinction event: evidence from a new genus and species, Grimmenodon aureum
A new genus and species of pycnodontiform fishes, Grimmenodon aureum, from marginal marine, marine-brackish lower Toarcian (Harpoceras exaratum ammonite subzone) clay deposits of Grimmen in northeastern Germany is described. The single specimen represents a diagnostic left prearticular dentition characterized by unique tooth arrangement and ornamentation patterns. Grimmenodon aureum, gen. et sp...
متن کاملAn Ancient Gene Network Is Co-opted for Teeth on Old and New Jaws
Vertebrate dentitions originated in the posterior pharynx of jawless fishes more than half a billion years ago. As gnathostomes (jawed vertebrates) evolved, teeth developed on oral jaws and helped to establish the dominance of this lineage on land and in the sea. The advent of oral jaws was facilitated, in part, by absence of hox gene expression in the first, most anterior, pharyngeal arch. Muc...
متن کاملAn antiarch placoderm shows that pelvic girdles arose at the root of jawed vertebrates.
Almost all gnathostomes or jawed vertebrates (including osteichthyans, chondrichthyans, 'acanthodians' and most placoderms) possess paired pectoral and pelvic fins. To date, it has generally been believed that antiarch placoderms (extinct armoured jawed fishes from the Silurian-Devonian periods) lacked pelvic fins. The putative absence of pelvic fins is a key character bearing on the monophyly ...
متن کاملPlacoderms and the evolutionary origin of teeth: a comment on Rücklin & Donoghue (2015)
The extinct Devonian placoderms (armoured jawed fishes) [1,2] are central to the question of tooth origins, because some have denticulate ‘toothplates’ within the mouth cavity. A key question is whether these gnathal plates were modified from external dermal bones, or had ‘denticles’ representing true teeth with pulp cavities [3, fig. 2h]. The recent contribution by Rücklin & Donoghue [4] confu...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Science
دوره 299 5610 شماره
صفحات -
تاریخ انتشار 2003