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Are agnathans true vertebrates?

Looking for an answer to the question: Are agnathans true vertebrates? On this page, we have gathered for you the most accurate and comprehensive information that will fully answer the question: Are agnathans true vertebrates?

Are ostracoderms placoderms?

In those days, placoderms were thought to be shelled jawless fish akin to ostracoderms. Some naturalists even suggested that they were shelled invertebrates or even turtle-like vertebrates.


Are hagfish Agnatha?

hagfish, also called slime eel, any of about 70 species of marine vertebrates placed with the lampreys in the superclass Agnatha.


What features separate the Agnathans from all other vertebrates?

Evolution. If evidence from fossil and living forms is combined, the Agnatha are distinguishable from the other craniates (Gnathostomata) by what they lack: jaws, lateral fins supported by fin rays, vertebrae, a horizontal semicircular canal in the ear, and genital ducts.


Do lampreys have vertebrae?

The unique morphological characteristics of lampreys, such as their cartilaginous skeleton, suggest they are the sister taxon (see cladistics) of all living jawed vertebrates (gnathostomes). ... Instead of true vertebrae, they have a series of cartilaginous structures called arcualia arranged above the notochord.


What Kingdom is a hagfish in?

Animal Hagfish/Kingdom


Are hagfish and lampreys vertebrates?

Hagfish and lampreys are the only living representatives of the jawless vertebrates (agnathans), and compared with jawed vertebrates (gnathostomes), they provide insight into the embryology, genomics, and body plan of the ancestral vertebrate. ... paraphyly of cyclostomes.


How are hagfish different from other vertebrates?

Myxiniformes Neomyxine Hagfish/Lower classifications


What is the difference between ostracoderms and placoderms?

Ostracoderms are extinct, primitive jawless fishes that were covered in an armor of bony plates while placoderms are extinct, primitive jawed fishes. Placoderms are among the earliest jawed vertebrates to appear on earth.


Are Agnatha vertebrates or invertebrates?

Agnatha (Marsipobranchii; phylum Chordata, subphylum Vertebrata) A superclass of jawless, fish-like vertebrates that have sucker-like mouths and lack paired fins. The Agnatha includes some of the earliest primitive vertebrates as well as the extant lampreys, slime-eels, and hagfish.


Are hagfish invertebrates?

Their classification as agnathans places hagfish as elementary vertebrates in between invertebrates and gnathostomes. ... The term "Craniata" was used to refer to animals that had a developed skull, but were not considered true vertebrates.


Do Ostracoderms have vertebrates?

ostracoderm, an archaic and informal term for a member of the group of armoured, jawless, fishlike vertebrates that emerged during the early part of the Paleozoic Era (542–251 million years ago).


Are there different species of hagfish?

Hagfish Species There are approximately 70-82 species, with the number varying depending on the source due to the continuous discovery of new species. The most studied species, with the scientific name Myxini glutinosa, is also called the Atlantic hagfish.


Is a lamprey a vertebrate or invertebrate?

Lampreys are jawless fishes (or agnathans), closely related to other living vertebrates, the jawed vertebrates (or gnathostomes). They, along with hagfish, are the only known surviving lineage of once diverse groups of jawless fishes.


Are ostracoderms Marine?

Ostracoderms and bony fishes are represented in both marine and freshwater deposits of the Devonian period. A marine origin for the vertebrates is supported by the fact that the three protochordate groups, Hemichordata, Urochordata, and Cephalochordata, are marine.


Is a lamprey a hagfish?

Yes. Lamprey and hagfish are both jawless fishes. They are the only living members of the taxonomical class Agnatha (Greek for “no jaws”).


What is the difference between hagfish and lamprey?

Hagfish is an eel-like slime producing marine jawless fish while lamprey is an eel-like jawless fish that lives in coastal and freshwaters. Hagfish does not possess vertebra while lamprey has vertebra. Hence, hagfish is not considered as a vertebrate while lamprey is a vertebrate.


How are lampreys vertebrates?

The unique morphological characteristics of lampreys, such as their cartilaginous skeleton, suggest they are the sister taxon (see cladistics) of all living jawed vertebrates (gnathostomes). ... Instead of true vertebrae, they have a series of cartilaginous structures called arcualia arranged above the notochord.


Are ostracoderms gnathostomes?

' How- ever, current vertebrate phylogenies suggest that most, if not all, 'ostracoderms' are in fact jawless stem gnathostomes, which retain certain features that were once regarded as unique to the cyclos- tomes, such as gill pouches or lack of horizontal semicircular canal.


Do Agnathans have bones?

Agnatha. Class Agnatha consists of an ancient group of animals similar to fish but with some very noticeable differences. ... Agnathans lack an internal skeleton made of ture bone. As with sharks (another ancient group), the internal skeleton consists primarily of cartilage.


What are the characteristics of Agnathans?

Key Features of AgnathaJaws are absent.Paired fins are generally absent.Early species had heavy bony scales and plates in their skin, but these are not present in living species.In most cases the skeleton is cartilaginous.The embryonic notochord persists in the adult.Seven or more paired gill pouches are present.

Are agnathans true vertebrates? Video Answer

biology 235 (agnathans)

Are agnathans true vertebrates? Expert Answers

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Greta ⭐ Answeregy Expert

Why are Agnatha considered vertebrates?

Agnathans: Jawless Fishes Hagfishes and lampreys are recognized as separate clades, primarily because lampreys are true vertebrates, whereas hagfishes are not. A defining feature of agnathans is the lack of paired lateral appendages or fins. Present-day jawless fishes lack bone in their scales. Beside this, what do Agnatha have instead of bones?

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Kacen ⭐ Answeregy Expert

29.2A: Agnathans: Jawless Fishes - Biology LibreTexts

Most agnathans are now extinct, but two branches exist today: hagfishes (not true vertebrates) and lampreys (true vertebrates). The earliest jawless fishes were the ostracoderms, which had bony scales as body armor. Hagfish are eel-like marine scavengers in the clade Myxini that produce slime and can tie themselves into knots.

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Ashley ⭐ Answeregy Expert

True or False: All members of agnatha have a cranium and ...

True or False: All members of agnatha have a cranium and vertebrae. Agnatha: ... Chordates are animals that usually have a vertebrate, as well as gills, notochords, and other traits. Learn about ...

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Carolyn ⭐ Answeregy Expert

Biology 2e, Biological Diversity, Vertebrates, Fishes ...

Jawless fishes (Agnatha) are craniates representing an ancient vertebrate lineage that arose over 550 million years ago. In the past, hagfishes and lampreys were sometimes recognized as separate clades within the Agnatha, primarily because lampreys were regarded as …

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Agnatha - Wikipedia

Agnatha ( / ˈæɡnəθə, æɡˈneɪθə /, Ancient Greek ἀ-γνάθος 'without jaws') is an infraphylum of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present ( cyclostomes) and extinct ( conodonts and ostracoderms) species. Among recent animals, cyclostomes are sister to all vertebrates with jaws, known as gnathostomes.

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Johnathan ⭐ Answeregy Expert

Why are members of the class Agnatha included in vertebrates?

Class Agnatha: The class Agnatha is part of the phylum Chordata. All living members of the phylum are also classified as vertebrates, though some find this confusing.

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Dalilah ⭐ Answeregy Expert

Class Agnatha – The Biology Classroom

Class Agnatha (Jawless fish) General Characteristics: Predicted to be the first vertebrates -> oldest known fossils/most similar to lancets, tunicates. (~550 million years ago) Have no fins, no scales, and no jaw. Skeleton of cartilage (firm, flexible tissue not as hard as bone)

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Mairead ⭐ Answeregy Expert

Why do we group agnathans as vertebrates even though they ...

However DNA evidence shows that they do have the machinery to make vertebrae and so are considered to have a degenerate vertebral column, having descended from ancestors that did have one. So all the agnathans are now back as true vertebrates. 51 views View upvotes Quora User , An …

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Johnny ⭐ Answeregy Expert

agnathan | Definition, Characteristics, Habitat, Examples ...

agnathan, (superclass Agnatha), any member of the group of primitive jawless fishes that includes the lampreys (order Petromyzoniformes), hagfishes (order Myxiniformes), and several extinct groups. Hagfishes are minor pests of commercial food fisheries of the North Atlantic, but lampreys, because

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Darci ⭐ Answeregy Expert

4 - Vertebrate Anatomy - Agnathans Flashcards | Quizlet

- small - aprox 3 cm long and very fish like in appearance - despite how old they are, they appear to be more derived than living hagfish - might have cartilage but don`t have bone or mineralized scales Vertebrate characteristics of cambrian agnathans (1) cranium supporting brain (2) w-shaped myomeres (true vert. characteristic)

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Agnatha - Lamprey, Hagfish | Wildlife Journal Junior

Agnatha are jawless fish. Lampreys and hagfish are in this class. Members of the agnatha class are probably the earliest vertebrates. Scientists have found fossils of agnathan species from the late Cambrian Period that occurred 500 million years ago. Members …

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Chordate, Vertebrate, and Agnatha Test Review Flashcards ...

False: Lancelets. True or False: Jawless vertebrates are Agnatha. True. True or False: Chordates are protostomes. True. True or False: Chordates reproduce sexually. True. True or False: Vertebrates have unsegmented body plans. False: Vertebrates have segmented body plans.

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Penelope ⭐ Answeregy Expert

Jawless Vertebrates - Digital Atlas of Ancient Life

The jawless vertebrates (traditionally recognized as "agnathans") are identified by the gray box and star. This tree was compiled using several recent publications, including Brazeau and Friedman (2015), Brazeau and de Winter (2015), Janvier (2015), Janvier and Sansom (2016), Donoghue (2017), Miyashita et …

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Kwame ⭐ Answeregy Expert

Vertebrate Zoology

Agnatha Hagfish & Lamprey Vertebrate Zoology Key Features Jaws are absent. Paired fins are generally absent. Early species had heavy bony scales and plates in their skin Key features con’t In most cases the skeleton is cartilaginous. The embryonic notochord persists in the adult. Seven or more paired gill pouches are present.

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Karen ⭐ Answeregy Expert

agnathan - Evolution and classification | Britannica

If evidence from fossil and living forms is combined, the Agnatha are distinguishable from the other craniates (Gnathostomata) by what they lack: jaws, lateral fins supported by fin rays, vertebrae, a horizontal semicircular canal in the ear, and genital ducts.

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Briella ⭐ Answeregy Expert

The Origin Of Vertebrates And The Rise Of Fishes

A. Agnatha- jawless vertebrates B. Gnathostoma- vertebrates with jaws The animals you know as FISH are actually several different animals - some agnathans and some gnathostomes. In other words, fish is a common name, like worm, and not a taxonomic name. The fish include 1. All of the Superclass Agnatha - …

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What does the agnathans group include? | Socratic

AGNATHANs are 'jaw less' vertebrates: gnathos in Greek means jaw. They were the first vertebrate to evolve in early Palaeozoic, more than 500 million years ago. Superclass Agnatha is included under phylum Chordata, subphylum Vertebrata. Very few living agnathans are present today, all are aquatic. There is a single living class Cyclostomata, that includes all living agnathans.

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Rusty ⭐ Answeregy Expert

Agnatha and Gnathostomata Differences (10 Very Important )

Agnatha vs Gnathostomata: Summary: pharyngeal gill slits. Image Credit: Chegg. Both Agnatha and Gnathostomata are vertebrates and both have many similarities with fish. Agnathans are jawless fish-like organisms without paired appendages but Gnathostomata has jaw guarded mouth opening and has paired appendages.

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Roy ⭐ Answeregy Expert

Vertebrates: Definition, Classification and Characteristics

Vertebrates and invertebrates evolved from a common ancestor that was speculated to have lived around 600 million years ago. Evidence of true vertebrates began to appear 525 million years ago and ever since then, vertebrates have branched off into a long lineage that includes armoured fish and giant sauropods to woolly mammoths and modern man.

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Class Agnatha - Marine Phyla - Google Search

As the most primitive members of the vertebrates, agnathans differ from all others in several important respects. First, they lack hinged upper and lower jaws and instead have unhinged circular...

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Claude ⭐ Answeregy Expert

Class Agnatha - The Tree of Life

Agnathans have a notochord that remains present throughout their whole life. This notochord is the first primitive vertebral column (spine). The notochord provides support to the hagfishes body. Unlike true vertebrates, hagfishes do not replace the notochord with a vertebral column during development.

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Belen ⭐ Answeregy Expert

What is an example of Agnatha? – Colors-NewYork.com

Are extinct Agnathans? Most agnathans are now extinct, but two branches exist today: hagfishes (not true vertebrates) and lampreys (true vertebrates). The earliest jawless fishes were the ostracoderms, which had bony scales as body armor. Why are jawless fish still around?

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Summer ⭐ Answeregy Expert

Difference Between Agnathans and Gnathostomata | Compare ...

The key difference between agnathans and Gnathostomata is the possession of a jaw. Agnathans do not possess a jaw while Gnathostomata possesses true jaws. Besides, a further difference between agnathans and Gnathostomata is that the Gnathostomes possess paired appendages and fins, while the Agnathans do not possess paired appendages and fins.

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Agnathans | Encyclopedia.com

Agnatha. Agnatha A subphylum or superclass of marine and freshwater vertebrates that lack jaws. They are fishlike animals with cartilaginous skeletons and well-developed sucking mouthparts with horny teeth. The only living agnathans are lampreys and hagfishes (class Cyclostomata), which are parasites or …

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Agnatha - an overview | ScienceDirect Topics

C.R. Slater, in Encyclopedia of Neuroscience, 2009 Agnatha (Hagfish, Lamprey) In primitive vertebrates of the class Agnatha, the arrangement of muscles and their innervation differ from that in other vertebrates.Within the segmental myotomes, the muscle fibers are arranged into ‘muscle units’ in which large-diameter ‘white’ fibers are placed centrally.

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Lab3 Assignment.docx - Vertebrate Lab Lab Assignment 3(20 ...

Lab Assignment 3: (20 pts) Agnathans (Jawless Fishes) ... Unlike true vertebrates hagfishes do not replace the notochord with a vertebral column during development. Since they have a cartilaginous skull, they are classified under the clade Craniata (Reference 3). Lamprays in the other hand do have a complete, rather than partial, skull.

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Melanie ⭐ Answeregy Expert

INTRODUCTION TO VERTEBRATE NATURAL HISTORY

Agnatha - jawless vertebrates including the Myxini and Cephalaspidomorpha Gnathostomes - vertebrates with jaws derived from the mandibular arch, which may have (in primitive vertebrates) supported gills; includes Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves, and Mammalia

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Warren ⭐ Answeregy Expert

Fishes – Biology 2e

Jawless fishes (Agnatha) are craniates representing an ancient vertebrate lineage that arose over 550 million years ago. In the past, hagfishes and lampreys were sometimes recognized as separate clades within the Agnatha, primarily because lampreys were regarded as …

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(PDF) Agnatha (Lampreys, Hagfishes, Ostracoderms)

Agnathans are an ensemble of jawless (nongnathostome) vertebrates, some of which are more closely related to the gnathostomes than others. Living agnathans fall into two groups, hagfishes ...

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Norman ⭐ Answeregy Expert

Agnathans | Article about agnathans by The Free Dictionary

Agnatha are distinguished from all the remaining vertebrates, the Gnathostomata, by the absence of real jaws, and, in the ones living today, by the absence of paired extremities, as well as by the presence of an unpaired nostril. Agnatha are also called Marsipobranchia, because their gills look like pouches.

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Biology, Biological Diversity, Vertebrates, Fishes | OERTX

Jawless fishes are craniates that represent an ancient vertebrate lineage that arose over one half-billion years ago. In the past, the hagfishes and lampreys were classified together as agnathans. Today, hagfishes and lampreys are recognized as separate clades, primarily because lampreys are true vertebrates, whereas hagfishes are not.

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Agnatha - Simple English Wikipedia, the free encyclopedia

The Agnatha (Greek = 'no jaws') are a superclass of vertebrates.They are jawless fish.. The Agnatha as a whole may be paraphyletic. This means it is a convenient holdall term, which does not follow the rules of cladistics.For example, most extinct agnathans belong to the stem group (ancestral group) of gnathostomes. But according to the rules, one sister group should not contain ancestors of ...

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Evolution of vertebrae notes - BIOE 134/L - Comparative ...

• only living agnathans are the boneless cyclostomes–– hagfi shes, & lampreys Cyclostomes = Pro xies for the most primitive vertebrates • Prevertebrates were suspension feeders but change d and came to depend on a muscularized pharynx to produce feeding and

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Rose ⭐ Answeregy Expert

29.2: Fishes - Biology LibreTexts

Jawless fishes are craniates that represent an ancient vertebrate lineage that arose over one half-billion years ago. In the past, the hagfishes and lampreys were classified together as agnathans. Today, hagfishes and lampreys are recognized as separate clades, primarily because lampreys are true vertebrates, whereas hagfishes are not.

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BIO 342 Comparative Vertebrate Anatomy - Review Questions ...

Which groups of vertebrates exhibit (or exhibited) true powered flight (p.335)? What are the functions of a bird's primary. feathers, secondary feathers (p.336; Figure 9.43 - p.338)? Ch. 10 - What are electric organs & how many species of fish have such organs (p.346)?

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Colton ⭐ Answeregy Expert

Biology, Biological Diversity, Vertebrates, Chordates | OERTX

Vertebrates are grouped based on anatomical and physiological traits. More than one classification and naming scheme is used for these animals. Here we will consider the traditional groups Agnatha, Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves, and Mammalia, which constitute classes in the subphylum Vertebrata.

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Markia ⭐ Answeregy Expert

When did Agnatha first appear in the fossil record?

Also question is, when did the Agnatha first appear in the fossil record? 420 million years ago. Furthermore, what era did the first fish appear? During the Cambrian period, the first fish-like creatures (although definitely not recognized as true fish by paleontologists) …

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Kelly ⭐ Answeregy Expert

Diversity of Vertebrates

Agnatha - jawless vertebrates, including Myxini and Cephalaspidomorpha Gnathostomes - vertebrates with jaws derived from the mandibular arch, which may have (in primitive vertebrates) supported gills. Includes Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves, Mammalia ... The remaining vertebrate orders are Gnathostomes (possess true jaws ...

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Agnatha | Article about Agnatha by The Free Dictionary

Agnatha. a superclass of lower vertebrate animals. Agnatha are distinguished from all the remaining vertebrates, the Gnathostomata, by the absence of real jaws, and, in the ones living today, by the absence of paired extremities, as well as by the presence of an unpaired nostril. Agnatha are also called Marsipobranchia, because their gills look ...

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Christopher ⭐ Answeregy Expert

Classification of Living Things: Classes of Vertebrates

Three of the vertebrate classes are fish. The most primitive of these is Agnatha.It consists of jawless fish that do not have scale s. These are the lampreys and hagfish. Fish that have skeletons consisting of hard rubber-like cartilage rather than bone are members of the …

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Cathleen ⭐ Answeregy Expert

Vertebrates - Vertebrata - the Animal Encyclopedia

Vertebrates (Vertebrata) are a group of chordates that includes birds, mammals, fishes, lampreys, amphibians, and reptiles. Vertebrates have a vertebral column in which the notochord is replaced by multiple vertebrae that form a backbone. The vertebrae surround and protect a nerve cord and provide the animal with structural support.

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Learn About Jawless Vertebrates | Chegg.com

The reptiles then evolved as the first amniotic vertebrates. Jawless Vertebrates or Agnathans have pouch-like gills that open through small pores as opposed to slits that are present in vertebrates with jaws. Agnathans primitively lack jaws and show a persistent notochord. ... Absence of true teeth, jaws, and limbs. Their skeletons are made of ...

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Bernadette ⭐ Answeregy Expert

AGNATHANS, THE JAWLESS FISHES

AGNATHANS, THE JAWLESS FISHES Two jawless fish are known from the Early Cambrian. Myllokumingia had a head and trunk, a dorsal fin, a ventral fin (that might have been paired), 5-6 gill pouches, around 25 muscle segments (myomeres), a pharynx, an intestine, a notochord, and perhaps a pericardial cavity. With such features it is similar in complexity to the most primitive fish alive today, …

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29.2 Fishes - Biology 2e | OpenStax

Jawless Fishes: Superclass Agnatha. Jawless fishes (Agnatha) are craniates representing an ancient vertebrate lineage that arose over 550 million years ago. In the past, hagfishes and lampreys were sometimes recognized as separate clades within the Agnatha, primarily because lampreys were regarded as true vertebrates, whereas hagfishes were not.

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Vertebrate - Wikipedia

Vertebrates originated about 525 million years ago during the Cambrian explosion, which saw a rise in organism diversity.The earliest known vertebrate is believed to be Myllokunmingia. One of many early vertebrates are Haikouichthys ercaicunensis.Unlike the other fauna that dominated the Cambrian, these groups had the basic vertebrate body plan: a notochord, rudimentary vertebrae, and a well ...

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How many pairs of gills are found in jawless fish ...

The Agnatha are ectothermic or cold blooded, with a cartilaginous skeleton, and the heart contains 2 chambers. Are extinct Agnathans? Most agnathans are now extinct, but two branches exist today: hagfishes (not true vertebrates) and lampreys (true vertebrates). The earliest jawless fishes were the ostracoderms, which had bony scales as body armor.

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Evolutionary history of vertebrates | Fossil Wiki | Fandom

The first vertebrates appeared about 500-450 million years ago, during the duration of the Ordovician Period. The first member of this diverse group was represented by a species of jawless fish. This jawless fish, being the most basal species of this group, can be considered the ancestor of all vertebrates.

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