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The term paraphyly, or paraphyletic, derives from the two Ancient Greek words παρά (pará), meaning "beside, near", and φῦλον (phûlon), meaning "genus, species", [2] [3] and refers to the situation in which one or several monophyletic subgroups of organisms (e.g., genera, species) are left apart from all other descendants of a unique common ancestor.
Fishes are a paraphyletic group and for this reason, the class Pisces seen in older reference works is no longer used in formal taxonomy.Traditional classification divides fish into three extant classes (Agnatha, Chondrichthyes, and Osteichthyes), and with extinct forms sometimes classified within those groups, sometimes as their own classes: [1]
Cladistic classification of Sarcopterygii is the classication of Sarcopterygii as a clade containing not only the lobe-finned fishes (coelacanths and lungfish) but also the tetrapods, which are closely related to lungfish. The taxon Sarcopterygii was traditionally classified as a paraphyletic group considered either a class or a subclass of ...
Outline of fish. The following outline is provided as an overview of and topical guide to fish: Fish – any member of a paraphyletic group of organisms that consist of all gill -bearing aquatic craniate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as ...
A fish (pl.: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits.Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and acanthodians.
Psarolepis. Achoania. Actinopterygii (ray-finned fish) Sarcopterygii (lobe-finned fish, including tetrapods) Osteichthyes (/ ˌɒstiːˈɪkθi.iːz /), also known as osteichthyans or commonly referred to as the bony fish, is a diverse superclass of vertebrate animals that have endoskeletons primarily composed of bone tissue.
Cladistics (/ kləˈdɪstɪks / klə-DIST-iks; from Ancient Greek κλάδος kládos 'branch') [1] is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived characteristics ...
Sarcopterygii (/ ˌ s ɑːr k ɒ p t ə ˈ r ɪ dʒ i. aɪ /; from Ancient Greek σάρξ (sárx) 'flesh' and πτέρυξ (ptérux) 'wing, fin') — sometimes considered synonymous with Crossopterygii (from Ancient Greek κροσσός (krossós) 'fringe') — is a clade (traditionally a class or subclass) of vertebrate animals which includes a group of bony fish commonly referred to as lobe ...