Talk:Rodent

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[edit] Muroidea

The Muroids (mouse superfamily) are a mess and are only beginning to be resolved. I'm not entirely sure where the taxonomy from this page comes from, it's similar to but not exactly like Chaline and colleagues' 1977 paper in Mammalia. This is a pretty outdated taxonomy that's not seen much anymore except for in some of the paleontological literature. The Muridae approach takes the philosophy of we really don't know and if we guess we're wrong, so let's put all 1,000 species in the same family for convenience. Based on the much more recent molecular work (i.e. Adkins and Steppan and their approach in a 2004 Systematic Biology article), the Cricetinae (hamsters) would be placed in the family Cricetidae in the superfamily Muroidea. Muridae would be restricted to the Murinae, Deomyinae, Lophiomyinae, and Gerbillinae. I'm new in town, but hoping to flesh out the muroid rodents a bit. Aranae 18 Nov 2004.

[edit] Cricetidae

Cricetidae is listed as a family on this page, but as a subfamily (Cricetinae) on the Muridae page. Which is it? john 18:40, 12 Mar 2004 (UTC)

[edit] Arvicolidae

Where's Arvicolidae family? Palearctic voles and lemmings? --Joy [shallot] 09:51, 3 Feb 2005 (UTC)

Oh, it's spelled with a n instead of a d here... weird. I made a redirect at Arvicolidae now. --Joy [shallot]

The term Arvicolidae is used when the voles are granted full family status as has rarely been seen outside of Russian and paleontological literature. This is usually on the basis of their unique teeth. They are more closely related to the hamsters than anything else is, so such an elevation would require all the families listed on the page, plus at least splitting the New World rats and mice into another full family, Sigmodontidae (or Hesperomyidae). The same is true for the rare occasion when you might see Gerbillidae. To recognize full family status for gerbils would require Lophiomyidae and Deomyidae to be families as well. The muroid pages currently follow Steppan and Adkins (2004), which is really the only comprehensive and well-supported phylogenetic analysis to date. Very good call on the redirect. --Aranae 20:48, Feb 3, 2005 (UTC)

[edit] Article verification request

Hystricognathi was created by an account of a known vandal/hoaxster. Verification by experts is necessary. mikka (t)

[edit] Rodent Hybrids

I have removed the following text that was just added to the article page:

Common Hamster and Golden Hamster have mated and resulted in pregnancy in a Female Golden Hamster, but no offspring were born. Golden Hamsters and Romanian Hamsters produce sterile hybrid offspring which are intermediate in type. Campbell's Dwarf Russian Hamster hybridizes freely with the Siberian Hamster (Winter White Russian Dwarf Hamster) and produces fertile hybrid offspring; these may be sub-species. Norway (Brown) Rats and Black Rats will mate and will produce live offspring, but the offspring die shortly after birth.

Among the Jirds (a type of gerbil), many of the Shaw's Jirds kept as pets in the UK are apparently hybrids between the Shaw's Jird and Libyan Jird (they are known as UK Shaw's Jirds to differentiate them from the true species). Hybrids exist between the Pallid Gerbil and Cheesman's Gerbil. Although rodent fanciers may deplore the hybrid strains or try to segregate the species, nature is not always observant of human-declared species boundaries!

There are numerous natural and artificial hybrids between different European mice (Mus musculus x M domesticus, M musculus x M castaneus) and laboratory hybrids between mice (M musculus x M spretus, M musculus x M spicilegus, M musculus x M macedonicus) However other mice could not hybridise with M musculus. M musculus x M caroli hybrids were either stillborn or failed to thrive after birth. M musculus x M cervicolor did not get beyond early embryo cell divisions. M musculus x M dunni also failed early in embryo development. Of those mouse hybrids that thrived, the male was sterile, but the female was fertile. There are also hybrids between the East European Vole and Common Vole.

Rabbits are frequently mistaken as rodents and have similar traits, but are actually lagomorphs. According to a publication in 1911, crosses were made between the common rabbit and the guinea-pig and were exhibited in the Zoological Gardens of Sydney, New South Wales. There have been several claims of rabbit/cavy (guinea pig) crosses since then.

Now that is truly strange.


At a minimum, this section needs cleanup. Overall, I think only a fraction of it is relevent to the page as a whole. Specific listings of hybrids are probably better represented on more specific genus/family level pages. The only exception to that might be the cavy/rabbit incident, but I'd like to see some documentation on that. --Aranae 21:55, 19 September 2005 (UTC)

[edit] Template:Rodents

In an attempt to start the switch for related articles toward the MSW3 taxonomy, I have created a new template Template:Rodents. I think the taxonomy applied in MSW3 is far more consistent with both the molecular and morphological literature and is a great improvement over what's listed here. This is true for at least extant taxa. Fossil taxa are far more difficult. I have tried to apply the results of Marivaux, et al. (2004, Zoological Journal of the Linnean Society, 142:105-134) where possible and relied on the more speculative McKenna and Bell (1997) when they lacked taxon sampling. McKenna and Bell could not be applied directly to the taxonomy in MSW3, because they conflict directly at several points. Besides, there have since been new discoveries and analyses that refute McK & B's hypotheses (i.e. the discovery of hystricognathous baluchimyines and the overall polyphyly of their Sciuravida). As a result, I've left everything in conflict in a big incertae sedis section at the bottom of the template.

The whole thing borders dangerously close to original research or original interpretation, but I'm not really sure how else to add fossil taxa to an exclusively extant taxonomy. Another thing I was unsure of are the families which are potentially non-rodent simplicidentates such as the Eurymylidae, Cocomyidae, Alagomyidae, and Ivanantoniidae. At present I have them on the rodents template, but it may be appropriate to remove them and treat them simply as simplicidentates or stem rodents. All of these groups have been argued as being rodents by one person or another.

I'd like to solicit comments before intensively applying this taxonomy to the rodent article and subpages. I'd particularly like to hear people's opinions on what to do with fossil taxa. --Aranae 04:40, 20 December 2005 (UTC)

[edit] More Mammal Species of the World 3rd edition

I would also suggest that we put together a list of changes from MSW3 that we intent to adopt. In particular new discoveries and new studies taht conflict with their proposed taxonomy. Here's a start: --Aranae 06:16, 20 December 2005 (UTC)

  1. Anything involving prehistoric taxa is not directly addressed and will require decisions on our part (see above).
  2. Laonastidae - new mammal family
  3. Jansa and Weksler (2004) found Lophiomyinae to be part of Muridae and unrelated to Cricetidae. This is the only molecular study to address this, but the statistical support was good. It is also consistent with certain morphology-based hypotheses.
  4. We currently separate Dipodidae and Zapodidae. Should this arrangement be retained or should all dipodids be included in Dipodidae? Also, what about Sicista? There's not much support for inclusion of the birch mice into Zapodidae. If we recognize Zapodidae, do we also need to recognize a Sicistidae? I would argue that we should either subsume them all into Dipodidae (as in MSW3) or recognize three families.
  5. Note that flying squirrels evolved from within the Sciurinae and no longer warrant subfamilial ranking.
  6. Also note the elevation of subfamilial status to Tachyoryctinae, Delanymyinae, and Leimacomyinae.
  7. Note the capybara probably evolved from within the Caviidae and is reduced to a subfamily of Caviidae. This is well supported genetically.
  8. I would argue that the data do not support separation of Otomyinae from Murinae. This is particularly true in studies that have been published in the last year or so and are probably too recent to be included. The otomyines are fairly clearly allied with the arvicanthine murines and these recent studies treat them as such.
  9. Separation of Cuniculidae and Dasyproctidae - molecular results suggest this is warranted. Also ICZN has ruled in favor of use of the genus name Cuniculus since the 2nd edition.

[edit] Embryology section

I have just pulled a new addition from the main page. It contains useful information, but is virtually incoherent in its current state. Copyediting will require more than just grammatical expertise. If anyone can help, please do so. --Aranae 16:15, 20 February 2006 (UTC)

== Embryology == * [[inversion of the germ layers]] = „turning“ = axial rotation is characteristic feature of rodents development from 7,5-8 days [[post coitum]] (6-8 pairs of [[somite]]s) to 9-9,5 days post coitum (14-16 pairs of [[somite]]s), [[Theiler stage]] 12-13). It is in all rodents but it isn't in other mammals.


== Embryology == * [[inversion of the germ layers]] = „turning“ = axial rotation of embryo is characteristic feature of rodents development occuring in all rodents but it isn't in other mammals. Turning of [[common house mouse]] embryo is from 7,5-8 days [[post coitum]] (6-8 pairs of [[somite]]s) to 9-9,5 days post coitum (14-16 pairs of [[somite]]s), [[Theiler stage]] 12-13).

Improvement of the section: --Snek01 15:11, 11 March 2006 (UTC)

[edit] beaver

i thought the beaver was the biggest rodent

That's wrong. Either the capybara or its close relative Hydrochoerus isthmius is the largest living species (I don't know which one is larger); there are even larger fossil rodents. Beavers are the largest members of their suborder, Castorimorpha, and presumably the largest rodents of the Holarctic. Ucucha 10:14, 17 August 2006 (UTC)

[edit] Diagram of a rodent?

Anyone can add a diagram showing the organs of a rodent, possibly brief explanation of the organs? Anyways, I hope that someone can add the digestive system of a rodent too. — Yurei-eggtart 15:57, 10 October 2006 (UTC)

And how about some discussion and closeups of rodent hands? They seem to be pretty well developed on this point. How do their hands compare with human and other hands? Jm546 18:03, 2 January 2007 (UTC)

[edit] Largest Rodent Phoberomys Pattersoni

Phoberomys pattersoni (It was 3 meters long, with an additional 1.5 meters tail) was huge does anyone think they can get bigger??

[edit] Copyright on this photo

has the copyright of this photo been checked? —The preceding unsigned comment was added by 172.188.235.98 (talk) 14:09, 29 December 2006 (UTC).

Which photo? - Adrian Pingstone 14:26, 29 December 2006 (UTC)

[edit] Is this true?

"rodents have even been known to force weaker members of their colonies to eat new food "to see if they die." Yahoo News Xiner (talk, email) 15:00, 28 February 2007 (UTC)

[edit] Fossil rodents

Regarding the natural history section. There are no fossil rodents prior to the Paleocene. There's nothing that anyone has even consider more closely related to rodents than lagomorphs. Multituberculates were certainly present, but they are not even remotely rodents. The hystricognaths as non-rodents warrants discussion, but there's basically no one left that ascribes to it. See Caleton and Musser (2005: Mammal Species of the World 3) for a very detailed discussion of that former controversy.

The second paragraph is basically wild rambling with no statements supported by citations. Caviomorphs as Atlantogenata?! I have certainly never seen anything remotely suggesting that. Certainly not molecules, morphology, fossils or even written opinions. Wood suggested they were related to North American franimorphs, but that just moved them nearer to the base of rodents not nearer to the base of placentals.

I renamed the section "Evolution" since that's the actual topic, removed the most rampant speculation, pulled a line from Cavia, which I think's a good quick way of addressing monophyly. It still needs LOTS of work. --Aranae 04:38, 29 April 2007 (UTC)

With rodent-like mammal, I was indeed referring to Multituberculata. I did not mean a "rodentiamorph" (if such thing exists) but only an animal with rodent-like characteristics, without implying a direct relationship to Rodentia.

I did not know that the hypothesis that hystricognaths are non-rodents is no longer regarded as likely. I'm sorry for that, I should have updated my knowledge on hystricognath evolution first.

The second paragraph....well I do not agree it was "rambling", but you are right that I should have provided sources for the statements I made. Caviomorphs being Atlantogenta is something that was suggested in an article I've read, but was at best highly speculative. It was based on the hypothesis that if Caviomorphs turn out to be non-rodents, they might have been endemic to Africa and later on South America as well. If that is true, it is likely they are related to the other endemic eutherians on these continents, like the Xenarthra and Afrotheria. That would make them Atlantogenata. But highly speculative, I have to admid.

The section on Meridiungulata was perhaps out of place in the context of this article, but I think it is a valid opinion nonetheless. Meridiungulata may be related to ungulates, but that assemblage turned out to be paraphylatic, as some are Afrotheres and not related to Artio/Perissodactyla. Why should this not be the case to Meridiungulata as well? If Afrotherian and Laurasiatherian ungulates developed convergently, is it not logical to consider the Meridiungulates as possible (South American) products of convergent evolution?

Don't mind my English, I'm not a native speaker. I'm sorry for the speculative statemens I've made. DaMatriX 23:13, 29 April 2007 (UTC)

[edit] Pre-historic rodents

The Flores Giant Rat is listed as pre-historic, but the linked article says that that species (Papagomys armandvillei) is vulnerable but not extinct. It goes on to say that a related species, P. theodorverhoeveni, known from the fossil record, is presumed to be extinct. Assuming hat "Pre-historic" means extinct in this context, the contradiction between the two articles should be resolved. —The preceding unsigned comment was added by Cerowyn (talk • contribs) 20:07, August 21, 2007 (UTC).

That's true. Papagomys armandvillei is still living, and it has been suggested that P. theodorverhoeveni is too. I replaced it with Spelaeomys, which is actually extinct. Ucucha 05:23, 22 August 2007 (UTC)

[edit] Rodents and rabies

Rodents have a carrier-immunity to the rabies virus, making them immune to the potentially infectious and lethal disease.[citation needed] They are carriers for most other animal-to-human illnesses, however, and still should not be agitated.[citation needed]

This needs checking: Google rodents rabies. Gordonofcartoon 05:08, 5 November 2007 (UTC)

[edit] Capybaras

Following the info in Caviidae and Hydrochoerinae, I've edited the classification to reflect that Capybaras are now considered members of Caviidae. JamesFox (talk) 15:01, 19 January 2008 (UTC)

[edit] Links

Why is it "hardly relevant" to link to a site that lists animals commonly mistaken for rodents? I think the link to that site should restored (animalsthatarenotrodents.com). —Preceding unsigned comment added by 75.72.101.205 (talk) 11:14, 4 June 2008 (UTC)