agnatha
Fish without jaws
Agnatha is the scientific classification for jawless fish—the most primitive vertebrates, including lampreys and hagfish.
The term comes from Greek meaning "without jaws," distinguishing these creatures from all other vertebrates, which have hinged jaws.
Modern agnathans are parasitic or scavenging, attaching to prey with sucker-like mouths.
Jawless parasitic fish
- hagfishJawless, slime-producing marine fish
- vertebrateSpinal column animal
- eel-likeElongated and sinuous
- marineRelating to the sea
freshwater · anadromous · benthic · parasitic · filter-feeder
Without a mandible
- cartilageFlexible connective body tissue
- notochordEmbryonic axial support structure
- bonelessHaving no skeleton
- endoskeletonBody's inner framework
ectothermic · mucus · slime · larvae · metamorphosis · pharynx
In earliest form
- ancestralOf one's forebears
- basalOf the foundation
- progenitorAncestor or originator
- ancientVery old indeed
early · prehistoric · evolutionary · divergence · phylogeny · craniate · transitional · living-fossil
Preserved ancient organism traces
- CambrianEarliest Paleozoic period
- OrdovicianPaleozoic geological period
- SilurianPaleozoic period, mid-range
- DevonianGeologic period, 419-359 million years ago
prehistoric · extinct · fossilization · stratigraphy · paleobiology · paleoecology · excavation · morphology
lamprey
Jawless parasitic fish
- hagfishJawless, slime-producing marine fish
- vertebrateSpinal column animal
- eel-likeElongated and sinuous
marine · freshwater · anadromous · benthic · parasitic · filter-feeder
jawless
Without a mandible
- cartilageFlexible connective body tissue
- notochordEmbryonic axial support structure
- bonelessHaving no skeleton
endoskeleton · ectothermic · mucus · slime · larvae · metamorphosis · pharynx
primitive
In earliest form
- ancestralOf one's forebears
- basalOf the foundation
- progenitorAncestor or originator
ancient · early · prehistoric · evolutionary · divergence · phylogeny · craniate · transitional · living-fossil
fossils
Preserved ancient organism traces
- CambrianEarliest Paleozoic period
- OrdovicianPaleozoic geological period
- SilurianPaleozoic period, mid-range
Devonian · prehistoric · extinct · fossilization · stratigraphy · paleobiology · paleoecology · excavation · morphology · phylogeny