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Agnatha (/ ˈ æ ɡ n ə θ ə, æ ɡ ˈ n eɪ θ ə /; [3] from Ancient Greek ἀ-(a-) 'without' and γνάθος (gnáthos) 'jaws') is a paraphyletic infraphylum [4] of non-gnathostome vertebrates, or jawless fish, in the phylum Chordata, subphylum Vertebrata, consisting of both living (cyclostomes) and extinct (conodonts, anaspids, and ostracoderms, among others).
Craniata also includes all lampreys and armoured jawless fishes, armoured jawed fish, sharks, skates, and rays, and teleostomians: spiny sharks, bony fish, lissamphibians, temnospondyls and protoreptiles, sauropsids and mammals. The craniate head consists of a three-part brain, neural crest which gives rise to many cell lineages, and a cranium ...
Lampreys / ˈ l æ m p r eɪ z / (sometimes inaccurately called lamprey eels) are a group of jawless fish comprising the order Petromyzontiformes / ˌ p ɛ t r oʊ m ɪ ˈ z ɒ n t ɪ f ɔːr m iː z /. The adult lamprey is characterized by a toothed, funnel-like sucking mouth.
A newfound fossil of a jawless fish is the oldest known vertebrate cranium preserved in 3D. The 455 million-year-old find could illuminate how vertebrate heads evolved.
Cyclostomi, often referred to as Cyclostomata / s ɪ k l oʊ ˈ s t ɒ m ə t ə /, is a group of vertebrates that comprises the living jawless fishes: the lampreys and hagfishes.Both groups have jawless mouths with horny epidermal structures that function as teeth called ceratodontes, and branchial arches that are internally positioned instead of external as in the related jawed fishes. [1]
Northern brook lampreys are jawless fishes, also known as cyclostomes.Northern brook lamprey are considered non-parasitic lamprey. [5] They have poorly developed teeth and a round, disc-like, subterminal mouth, called an oral-disc, for suction.
A lamprey (sometimes also called lamprey eel) is a jawless fish with a toothed, funnel-like sucking mouth, with which most species bore into the flesh of other fish to suck their blood. In zoology, lampreys are often not considered to be true fish because of their vastly different morphology and physiology.
Sacabambaspis is an extinct genus of jawless fish that lived in the Ordovician period. Sacabambaspis lived in shallow waters on the continental margins of Gondwana . [ 1 ] It is the best known arandaspid with many specimens known.