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Definition of Agnatha in English: Agnathaplural nounaɡˈneɪθəˈaɡnəTHə Zoology A group of primitive jawless vertebrates which includes the lampreys, hagfishes, and many fossil fishlike forms. 〔动〕无颌类脊椎动物。比较CYCLOSTOME Superclass Agnatha: the living forms are in the classes Myxini (hagfishes) and Cephalaspidomorphi (lampreys) Compare with cyclostome Example sentencesExamples - Here, we use the sequences of 35 nuclear protein-encoding genes to provide definitive evidence for the monophyly of the Agnatha (jawless vertebrates, a group encompassing the hagfishes and lampreys).
- In modern classification schemes, living vertebrates consist of two main groups, the jawless Agnatha (represented by hagfishes and lampreys) and the jawed Gnathostomata.
- By the mid 1970s, insulin had been isolated and sequenced from all classes of vertebrates, including Agnatha.
- The earliest fossil vertebrates belong to a group called the Agnatha or jawless vertebrates.
- All of these jawless fish are traditionally placed in the order Agnatha, but as you can see, this group is paraphyletic, including some but not all descendants of the common ancestor.
Derivativesadjective & noun Zoology Although a small number of bony fishes have brains of the same relative size as those in agnathans, most bony fishes have considerably larger brains for the same body size. Example sentencesExamples - Sufficient articulated material exists to show that these animals were agnathans (jawless vertebrates), with a bony exoskeleton, and they appear to have inhabited shallow-marine environments.
- One landmark event in vertebrate evolution was the evolution of jaws from agnathan ancestors, which was followed by the first appearance of the stomach.
- Above all, the appearance of diverse chordates and agnathans greatly expands our knowledge of the Cambrian explosion.
- Modern vertebrates are classified into two major groups, the gnathostomes (jawed vertebrates) and the agnathans (jawless vertebrates).
OriginFrom modern Latin Agnatha, from a-1 'without' + Greek gnathos 'jaw'. Definition of Agnatha in US English: Agnathaplural nounˈaɡnəTHə Zoology A group of primitive jawless vertebrates which includes the lampreys, hagfishes, and many fossil fishlike forms. 〔动〕无颌类脊椎动物。比较CYCLOSTOME Superclass Agnatha: the living forms are in the classes Myxini (hagfishes) and Cephalaspidomorphi (lampreys) Compare with cyclostome Example sentencesExamples - Here, we use the sequences of 35 nuclear protein-encoding genes to provide definitive evidence for the monophyly of the Agnatha (jawless vertebrates, a group encompassing the hagfishes and lampreys).
- The earliest fossil vertebrates belong to a group called the Agnatha or jawless vertebrates.
- By the mid 1970s, insulin had been isolated and sequenced from all classes of vertebrates, including Agnatha.
- In modern classification schemes, living vertebrates consist of two main groups, the jawless Agnatha (represented by hagfishes and lampreys) and the jawed Gnathostomata.
- All of these jawless fish are traditionally placed in the order Agnatha, but as you can see, this group is paraphyletic, including some but not all descendants of the common ancestor.
OriginFrom modern Latin Agnatha, from a- ‘without’ + Greek gnathos ‘jaw’. |