Talk:Megazostrodon

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An entry from Megazostrodon appeared on Wikipedia's Main Page in the Did you know? column on 1 December 2006.

[edit] Some amateur's questions

I made some small changes in wording: these are just my thoughts on content:

1. "covered in fur" Have skin imprints been recovered? Why we know this undisputed fact is as interesting as the fact itself.
2. "modern mammals" The change to modern mammals is more characteristic of the Paleocene-Eocene faunal turnover. Mammals may be thought of as "modern" but Megazostrodon isn't a "modern mammal".
3. "The other bones which once made up the jaw moved to the middle ear to create a hearing system." But had't this already occured among the cynodonts?
4. "change in the evolution of these first mammals was that they became warm-blooded." The morphological changes described are the result of being warm-blooded. The change to warm-bloodedness happened earlier, among the cynodonts.
5. "actually suckled their young" I don't see what "actually" is doing there; this is another case where why we know would be as interesting as the fact.--Wetman 13:37, 1 December 2006 (UTC)

Pronunciation: is "MEG-a ZOS-tro-don" the correct emphasis? --Wetman 13:40, 1 December 2006 (UTC)

I don't know if this is the right place to say this but there seems to be a problem with the link "canine" since it refers to an article about dogs and not about teeth.

Fixed. Yomangani^talk 17:31, 1 December 2006 (UTC)

Hi Wetman, I tweaked the format of your comments so we can reply to your points by number rather than re-quoting text. Ironically, I am now going to largely ignore the numbers and reply en masse. Most of these questions come down to providing refs, which is an onoging challenge. Many of the most reliable online sources are in "Members Only" science journals, which is discouraged because they are not readily verifiable for most readers. Regarding non-technical sources...the quality and reliability can vary wildly, and the sites are themselves difficult to authenticate.

Regarding question 2, The intro doesn't actually refer to Meg. as a modern mammal itself, but as "...first mammals" and "...the transition". Possibly this could be rewritten a bit for clarity, and the word "modern" may be confusing enough to remove if it troubles readers.

Needless to say, any contributions you make will be most welcome; especially if you have resources that could be used to add refs. Your obvious enthusiasim for the subject would clearly be an asset : ) Doc Tropics 17:56, 1 December 2006 (UTC)

Why not just insert the references in subscription on-line journals? More accessible sources could be added later. Explanations of why we know are better worked right into articles than left to be discovered in an unannotated reference, even an accessible one: it makes a richer, more informative read. I have to be cautious as a non-biologist: I tweak for clearer language rather than corrected information. --Wetman 02:39, 2 December 2006 (UTC)

Hi there, thanks for your questions Wetman-i'll try to answer them as best i can.

1. "covered in fur". There, as far as i'm aware, have never been any discoveries of fossil imprints of skin/fur from megazostrodon (in fact they are mostly known from their teeth). The claim comes from the fact that the animal was warm-blooded and the vast majority of warm blooded animals are covered with fur. It is, in effect, an educated guess (as much of paleontology is) but, from the sites and books i have read from it does seem to be the general concensus. This site offers some brief explanation of how hair developed in mammals.

okay, how is the footnote I've inserted? I'm sure it could be improved. --Wetman 02:39, 2 December 2006 (UTC)

1. "modern mammals". As Doc mentioned, the article doesn't call megazostrodon a modern mammal-it just suggests that it was in the final stages of becoming one. It is the penultimate stage in the transition between mammal like reptiles such as the cynodonts and true, modern mammals.

Is a change to "the transition between cynodont, or "mammal-like" reptiles and true mammals" an improvement? The next-to-last stage in the transition doesn't offer as clear a picture as "the final stage in the transition". Is that accurate? --Wetman 02:39, 2 December 2006 (UTC)

1. You're correct in saying that the cynodonts had already begun the process of developing the inner ear bones of mammals. However, they 'had' only begun the process and still had several bones making up their lower jaw (although less than common reptiles) and so there was still an evolutionary 'way to go' before the full inner ear set up was formed (as in the triconodonts).

This development is certainly worth a full paragraph in the article, though I'm not competent to write it. --Wetman 02:39, 2 December 2006 (UTC)

1. You are also right in saying that the cynodonts were probably warm blooded but 'probably' is the operative word here. There are structural aspects of megazostrodon which imply that it could not have been a cold-blooded animal. So, the answer is that there is a greater degree of certainty to the warm-bloodedness of megazostrodon and other early mammals than there is when discussing the mammal-like reptiles such as the cynodonts.

Isn't it axiomatic that warm-bloodedness precedes the morphological changes that are a consequence of warm-bloodedness? This could be expanded in the article to be more emphatic and better distinguished. --Wetman 02:39, 2 December 2006 (UTC)

1. Again, you're right that the word actually is a little out of place and i'll remove it when i've finished replying to you. However, the reason that there is no reference to how we know that the animals posessed mammary glands is that, as with the fur, it is the result of an 'educated guess' on the part of many paleonologists. The animal was a mammal and warm-blooded so almost certainly had sweat glands, animals which have sweat glands invariably have mammary glands as mammary glands are merely a specialised form of sweat gland. If you can think of a way of wording this so that it can be added into the article, please do so as it may add to the overall content.

This requires your knowledge to make plain. Sweat glands preceed mammary glands, but mammary glands are a development: there may be specific reasons to speculate that MegaZ suckled her young, though. The reasoning is more interesting than the mere result. --Wetman 02:39, 2 December 2006 (UTC)

As for the pronunciation, i haven't yet come across any articles or websites which give a phonetic pronunciation of megazostrodon but i have always used the emphasis which you placed on the syllables. Again, if you can find sources for it it may be a useful inclusion in the article. Thanks for your input and, for the record-most of us here are amatuers also-so you're not alone! Greebo cat 21:18, 1 December 2006 (UTC)

[edit] Nocturnal as a result of large brain

The reference that is linked to this statement does not seem to support that as it had a larger brain this made it nocturnal. Could you be a little clearer as to the source of this assertion.--Milynchke

You're right-it should link to the fur and fangs reference (number one) which does provide information on this-i just can't seem to fix it but i'll see if i can find someone who can! Greebo cat 20:35, 1 December 2006 (UTC)

Ok, should be fixed now-thanks to a little help from Doc Tropics . Thanks doc... Greebo cat 23:37, 1 December 2006 (UTC)

[edit] "non-mammalian characteristics"

This phrase is too generalized to transmit any real information: can the salient non-mammalian characteristics be identified, with a sentence or two explaining them to the reasonably-prepared layman? --Wetman (talk) 12:23, 6 February 2008 (UTC)

You're right, there should be a short description of some of the characteristics. Give me a short while to do some research and i'll add something in (if i can find any sources!) Have been out of the game for a while though so bear with me while i get back up to speed! Greebo cat (talk) 00:38, 19 February 2008 (UTC)