|WikiProject Animals||(Rated Start-class, Low-importance)|
|WikiProject Palaeontology||(Rated Start-class, Mid-importance)|
Mammal or Reptile?
What are they closely related to? --18.104.22.168 00:12, 21 April 2006 (UTC)
- Closely related to mammals (mammals evolved from them, specifically). No mammal-like "reptiles" are actually true reptiles, but synapsids. Both synapsids and reptiles evolved from a common ancestor, not one from the other, though synapsids are often called (incorrectly) reptiles anyway.Dinoguy2 03:01, 21 April 2006 (UTC)
Thanks for telling me! :) --22.214.171.124 02:11, 22 April 2006 (UTC)
Mentioning the duckbill as one example of what Cynodonts might have been like when alive could give a perspective. Its egg laying and the closest living example of such one intermediate evolutionary stage. —Preceding unsigned comment added by 126.96.36.199 (talk) 18:57, 6 September 2007 (UTC)
Though mammals are technically cynodonts in modern classifications, the Evolutionary history section appears to be discussing those that were not; no mammals, for example, are included among the "representative genera" listed. This is excusable, as mammals are not included among the "cynodonts" as the term is normally used, and they were classically regarded as separate groups. Not only does the section provide no references to reliable sources, however, there are a number of claims that seem unsupportable (at least as applied to nonmammalian cynodonts), and I am removing these. As far as I know:
- While Harderian glands provide evidence of hair in Morganucodon, there is no evidence for prior synapsids. Rostral pits in Thrinaxodon have long been rejected as evidence of whiskers.
- The fact that characteristics are shared between mammals and other cynodonts is not significant evidence for mammalian monophyly. Many of them were well known long before monophyly was generally accepted.
- While other tetrapods chew, only mammals masticate. Except for trithelodonts, molar occlusion is unknown in carnivorous nonmammalian cynodonts.
- There is no consensus as to why the dentary evolved to become the entire mandible. The structural integrity of the jaw is important to all gnathostomes and cannot explain why this development occurred differentially in the cynodonts.
- Since the ear structure of the nonmammalian cynodonts was not relevantly different from that of the sauropsids of the time, there is no reason to suppose that their hearing was superior.
Please restore any text for which appropriate references can be provided.
Cladogram needs to be split
Most of the extensive cladogram is not visible. Viewing the editing page and previewing, the following warnings are displayed:
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The cladogram needs to be split, and if that doesn't solve it, it needs to be trunctated and the farther branch details left to their corresponding articles. --Pitke (talk) 02:45, 9 December 2013 (UTC)
- Well, the cladogram has now been split into 3 but I think the "cuts" should be repositioned and renamed to correspond to more natural groups: the first cladogram ends cuts off Traversodontidae, which is fine as a monophyletic clade, but the cut at Brasilodontidae is confusing, since the clade presented as Brasilodontidae is actually an unnamed clade consisting of Brasilodontidae + (Tritylodontidae + Mammalia), but the way it is presented implies extant mammals are Brasilodontids. In the interest of information content and visual balance (roughly equal size and complexity), I advocate the major breaks on the cladogram be at major, defined nodes, such as, for instance 1) Everything until Cynognathia→ and Probainognathia→, 2)Cynognathia, and 3)Probainognathia. I haven't played around with how many branches this would entail or how it would look visually, and the nodes can change if needed, but it would be a more logical start. Another option would be to radically simplify (collapse) the cladogram to the level of family or subfamily, with full expansions and discussions on the relevant taxon articles (i.e. do we really need to see the complete inferred generic relationships of Traversodontidae in an article about Cynodonts in general?). This option would also reduce the inherent bias in only presenting one phylogeny.--Animalparty-- (talk) 19:19, 17 December 2013 (UTC)