Chordater

Chordater
Pikaia en af de tidligste chordater fra Prækambrium
Pikaia
en af de tidligste chordater fra Prækambrium
Videnskabelig klassifikation
DomæneEukaryota
RigeAnimalia (Dyr)
UnderrigeBilateria
RækkeChordata
Haeckel, 1874
Underrække
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Chordater eller rygstrengsdyr (Chordata) er en række af dyrene, der indeholder hvirveldyrene og to mindre grupper, trævlemunde og sækdyr, der repræsenterer efterkommere af de tidligst kendte chordater. Chordater er kendetegnet ved blandt andet en en ægte hale (hale, der sidder bagved anus), en dorsal nervestreng (rygmarven) og en rygstreng. Rygstrengen er hos trævlemunde og sækdyr, alene lavet af brusk og udgør det afstivende element ned gennem hele kroppen (hos sækdyr kun i larvestadiet). Hos de egentlige hvirveldyr (vertebrata) findes rygstrengen kun tidligt i fosterstadiet, hvor den senere erstattes af de egentlige ryghvirvler.

Den klassiske systematiske inddeling er:

Række: Chordata [1][2]

Krybdyr er ikke en veldefineret gruppe, da den er parafyletisk, idet krokodiller (og dinosaurer) er nærmere beslægtet med fugle end med de øvrige grupper af krybdyr (skildpadder, slanger og øgler).

Fylogenetiske slægstskab mellem de nulevende grupper af chordater.[3]

Chordata


Trævlemunde





sækdyr


Hvirveldyr
Rundmunde

Slimål



Lampretter





Bruskfisk




Strålefinnede fisk




Kvastfinnede fisk




Lungefisk



Tetrapoder

Padder


Amnioter

PattedyrEquus quagga




øgler og slanger



Archosaurer

Krokodiller



Fugle




Skildpadder















Referencer

  1. ^ Klassifikation iflg. Systema naturae 2000 (classification) – Taxon: Phylum Chordata Pr. 29 okt. 2006
  2. ^ Jørgen Mørup Jørgensen (2003). Introduktion til Chordatzoologi. Gads Forlag. ISBN 87-12-03788-5.
  3. ^ Putnam, N. H.; Butts, T.; Ferrier, D. E. K.; Furlong, R. F.; Hellsten, U.; Kawashima, T.; Robinson-Rechavi, M.; Shoguchi, E.; Terry, A.; Yu, J. K.; Benito-Gutiérrez, E. L.; Dubchak, I.; Garcia-Fernàndez, J.; Gibson-Brown, J. J.; Grigoriev, I. V.; Horton, A. C.; De Jong, P. J.; Jurka, J.; Kapitonov, V. V.; Kohara, Y.; Kuroki, Y.; Lindquist, E.; Lucas, S.; Osoegawa, K.; Pennacchio, L. A.; Salamov, A. A.; Satou, Y.; Sauka-Spengler, T.; Schmutz, J.; Shin-i, T. (juni 2008). "The amphioxus genome and the evolution of the chordate karyotype". Nature. 453 (7198): 1064-1071. Bibcode:2008Natur.453.1064P. doi:10.1038/nature06967. ISSN 0028-0836. PMID 18563158.

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Description des reptiles nouveaux, ou, Imparfaitement connus de la collection du Muséum d'histoire naturelle et remarques sur la classification et les caractères des reptiles (1852) (Crocodylus moreletii).jpg
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Title: Description des reptiles nouveaux ou imparfaitement connus de la collection du Muséum d'histoire naturelle et remarques sur la classification et les caractères des reptiles
Identifier: descriptiondesre00dum (find matches)
Year: 1852 (1850s)
Authors: Duméril, Auguste Henri André, 1812-1870
Subjects: Muséum national d\U+2019\histoire naturelle (France); Reptiles; Reptiles
Publisher: (Paris : Muséum d'histoire naturelle)
Contributing Library: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library
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Fig. 89. The Barramunda (Ceratodus) (From Queensland.)
Zoology of Egypt (1898) (Varanus griseus).png
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Identifier: zoologyofegypt01ande

Title: Zoology of Egypt
Year: 1898 (1890s)
Authors: Anderson, John, 1833-1900 Boulenger, George Albert, 1858-1937. Fishes of the Nile De Winton, William Edward
Subjects: Zoology
Publisher: London, B. Quaritch
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nitor griseus, Peters, Mon. Berl. Ak. 1870, p. 109. Varanus (Psammosaurus) arenarius, Bedr. Bull. Soc. Nat. Mosc. 1879, no. 3, p. 40.Varanus griseus, Blgr. Cat. Liz. B. M. ii. 1885, p. 306; Trans. Linn. Soc. Lond., Zool. v. 1889, p. 99; Fauna Brit. Ind., Rept. 1890, p. 163; Trans. Zool. Soc. xiii. 1891, p. 121; Boettger, Zool. Jahrb. iii. 1888, p. 904; Kat. Rept. Mus. Senck. 1893, p. 49; Anderson, Proc. Zool. Soc. 1895, p. 636 ; Herpet. Arabia & Egypt, 1896, pp. 34, 101; Zander, Zool. Garten, xxxvi. 1895, p. 298; Werner, Verh. zool.-bot. Ges. Wien, xliv. 1894, p. 79; Francaviglia, Boll. Soc. Rom. Zool. v. 1896, p. 46.1 $ . Suez. 1 cJ. Desert N.E. of Cairo.1 ? . Gizeh Desert.1 ? . Tel el Amarna. Prof. W. M. Flinders Petrie, D.C.L. 1 J1 and 1 juv. Suakin. Surgeon-Captain Penton, D.S.O. 2 £ and 2 ? . Suakin.1 J . Tokar. Teeth acute, compressed. Snout slightly depressed at the tip. Canthus rostralismoderately denned. Nostril oblique, rather large and crescentic, close to the eye, its
Text Appearing After Image:
w a Pi Zo ° < - Pi *° VAEANUS GEISBUS. 135 distance from the end of the snout being about four times greater than the intervalbetween it and the eye. Tail rounded at the base, slightly compressed posteriorly; nodorsal ridge. Digits rather short; claws strong and curved. Scales on the uppersurface of the head, including the supraoculars, very small, juxtaposed, smooth,generally hexagonal. Scales on the body and limbs small, rounded or oblong,sometimes feebly keeled, larger than ventrals, those on the sides of the neck generallyconical; ventrals smooth, 110-125 between the fold of the neck to the groin. Caudalscales small, more or less keeled above and below. General colour sandy yellow, with narrow brownish longitudinal lines varying inintensity along the side of the neck, and similarly coloured bands or lines across theback and tail, becoming lost in some adults towards the tip; the upper surface of thebody sometimes with yellow spots. The young is generally pale rufous yellow ab

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Tortoises, terrapins, and turtles London, Paris, and Frankfort :H. Sotheran, J. Baer & co.,1872.

biodiversitylibrary.org/page/2948267
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Forfatter/Opretter: Nobu Tamura (http://spinops.blogspot.com), Licens: CC BY 3.0
Pikaia gracilens, the earliest known vertebrate ancestor, from the Middle Cambrian of British Columbia, digital
The tailless batrachians of Europe (Page 194) (Pelobates fuscus).jpg

198 PELOEATID^.
smooth, and the dermo-ossification, as it develops,
produces granular asperities which may become con-
fluent into alveolar ridges, producing a pitted appear-
ance. In very old specimens the sutures between the
nasals, the ethmoid, and the fronto-parietal may become
obliterated.
Vomers rather large, variable in shape, extending
or not to the palatines, which are strongly ossified.
On the palatal side the ethmoid extends posteriorly to
about the middle of the length of the parasphenoid.
Latter large, J_- shaped, its anterior pointed extremity
produced to between the palatines. Pterygoids not
reaching the palatines, extensively in contact with
the parasphenoid. Stapes absent.
Mento-Meckelian or symphysial bones distinct on
the inner side only.
Hyoid a large broad cartilaginous plate, with slender
postero-lateral processes

anterior processes much
expanded and confluent with the lateral wings, en-
closing a small fenestra; ceratohyal cornua with
short posterior portion detached from the body of
the hyoid

thyrohyals large, massive, in contact at
the base, diverging and more or less expanded poste-
riorly.
Vertebral column once and a half to twice as long
as the skull. Spine closed above, the neural arch
produced posteriorly into a strong median process
between the zygapophyses. Three anterior diapo-
physes strong and long, especially the second, which
bears a more or less distinct dorsal knob or process
as on the corresponding rib of Discoglossus^ — the first
directed obliquely forwards, the second and third
nearly horizontal; the following short and slender,
directed forwards. Sacral vertebra with very strongly
dilated diapophyses, the transverse diameter of which
is twice and a half to nearly three times in the axial


urostyle short, not longer than the sacral wings, and
fused with the sacrum, to the diapophyses of which
its anterior portion contributes if these processes

be
FMIB 51327 Lancelet Branchiostoma carpilaerum.jpeg
Lancelet. Branchiostoma carpilaerum
  • Subject: Amphioxus, Cephalocordata
  • Tag: Fish
Cyprinus carpio3.jpg
Cyprinus carpio
Eptatretus springeri.JPG
Forfatter/Opretter: MyName (Tambja), Licens: CC BY-SA 3.0
Eptatretus springeri (Bigelow et Schroeder, 1952)
Python natalensis Smith 1840 white background.jpg
PYTHON NATALENSIS (Southern African Python) (Reptilia Plate 9) in A. Smith: Illustrations of the zoology of South Africa, Reptilia. Smith, Elder, and Co., London 1840
201109 Ciona.svg
Forfatter/Opretter: DataBase Center for Life Science (DBCLS), Licens: CC BY 4.0
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