Talk:Vertebrata

Distribution

• New Zealand Biodiversity: 1212 described marine species (Buckeridge & Gordon, 2000 [1])

etc.

Old talk

I don't think that a box telling the smallest and the biggest animals within a group meets the idea of a scientific database. I suggest not too keep that.

It gives an idea. --Henri de Solages 20:06, 25 November 2005 (UTC)

Dinosaurs

Are dinosaurs still classified as reptiles?

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Now there's a whole kettle of fish. Reptilia is now seen as a polyphyletic mixing pot, no longer defineable by certain characteristics. We know that birds are a subgroup of dinosaurs, and share far too many characteristics (feathers, homeothermy, medullary tissue, etc) to be able to say that dinosaurs are reptiles, and birds aren't. Now, classical Reptilia was basically lizards, snakes, turtles and crocs - but now, our understanding of the fossil record shows that this is not the case -0 where does one put early proto-mammals like _Cynognathus_? It had hair, but if it laid eggs (most likely based on anatomy) it comes under classical Reptilia.

Birds, crocs and dinosaurs comprise the Archosauria, with a few other relatives. Things like ichythyosaurids and plesiosaurids come under the Sauropterygia. Both of these come under the Sauropsida, which in turn comes under the neo-Reptilia.

This is sort of a condensed version - for more elaboration, I'd suggest checking info on both tolweb.org and dinosauricon.com (old version) to get a better idea of how complex we're talking.

Likewise, is it fair to assume this site attempts to utilise classical taxonomic structure, or phylogenetic synthesis? Both of the sites I've mentioned there attempt to utilise the latter, mainly because the old "Reptilia/Aves/Mammalia" falls down with our increasing knowledge of zoology and palaeontology..

Obsolete classification

I'm surprised to see reptilia as a class, since it's polyphyletic, and not to see gnathostomata as a clade of vertebrata. However, are vetebrata themself mono or paraphyletic ?
To my mind, non-monophylethic groups should be mentionned but immediately followed by the clear indication "paraphyletic" or "polyphylethic".--Henri de Solages 20:06, 25 November 2005 (UTC)

Vertebrata is a valid group. Unfortunately, it's classification seems a bit disorginized. It's probably even being changed again as you read this.

Much later, on reptilia. Is reptilia polyphyletic, that is are synapsida and diapsida derived from different pre-amniotic tetrapods. To answer the question, "are vetebrata themself mono or paraphyletic ?", could be both. Monophyly and paraphyly have to do with different things, monophyly with having a single ancestor, paraphyly with not including all descentants. The same applies to being both polyphyletic and paraphyletic, J.H.McDonnell (talk) 21:51, 1 January 2015 (UTC)

Explanation

Chordates have four distinguishing features: a hollow dorsal nerve cord, notochord, pharyngeal slits, and post-anal tail. Coupled with that, Vertebrates also have skulls and backbones.

• Acanthodii are extinct fishlike animals.
• Actinopterygii are fishes.
• Amphibia are animals like frogs or salamanders.
• Aves are birds like eagles or ostriches.
• Cephalaspidomorphi (Petromyzontida) are lampreys.
• Chondrichthyes are fishes with skeletons made of cartilage like sharks or rays.
• Dipnoi are air breathing fishes like lungfishes.
• Mammalia are animals with mammary glands like humans or whales.
• Myxini are hagfishes.
• Ostracodermi are extinct, jawless fishlike animals.
• Placodermi are extinct fishlike animals.
• Reptilia are reptiles like crocodiles or non-avian dinosaurs.
• Sarcopterygii (Actinistia) are lobe-finned fishes like Coelacanth.

Characteristics

	Common Name	Scientific Name	Length	Weight
Largest	Blue Whale	Balaenoptera musculus	25 - 27 m	100 - 120 t
Smallest	Stout Infantfish	Schindleria brevipinguis	8 mm	1 mg