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Topic: Hystricognaths

In the News (Mon 4 Jun 12)

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Iran

ANALYSIS

Pakistan

Family compact

	Comparative Placentation
		Reasoning by analogy from the several other hystricognaths studied, it is likely that this animal also has a mesometrial implantation and a generally similar placentation to that of other hystricognaths (Luckett, 1980).
		As has been indicated earlier, and as is true of other hystricognath rodents, this uterus is infiltrated by large numbers of trophoblastic cells that are especially deeply invasive into and around the myometrial arterioles.
		Hystricognath rodents have a pronounced subplacenta that is attached to the endometrium.
	medicine.ucsd.edu /cpa/pac.html (3745 words)

	Laotian Rock Rat - Wikipedia, the free encyclopedia
		They have a hystricognathous jaw and an enlarged infraorbital foramen consistent with a hystricomorphous zygomasseteric system.
		This would suggest that this living fossil represents the first living evolutionary split among the hystricognaths.
		The molecular analyses suggest that Laonastes is related to the living African hystricognaths such as the dassie rats and the Naked Mole Rat.
	en.wikipedia.org /wiki/Laonastidae (756 words)

	Comparative Placentation
		As a striking characteristic of hystricognaths (Luckett, 1985), the abembryonic trophoblast degenerates soon after implantation is finalized, coupled with the inversion of the germ layers at this time (Roberts and Perry, 1974).
		Because of the inversion of the germ layers in hystricognaths, the visceral yolk sac is endodermally covered, and in intimate contact with the endometrial surface epithelium of the uterus, and it is fetally vascularized towards its inner side (Figures 2, 3 and 7).
		Nedbal, M.A., Allard, M.W. and Honeycutt, R.L.: Molecular systematics of hystricognath rodents.
	medicine.ucsd.edu /cpa/degu.htm (3453 words)

	Porcupine. Who is Porcupine? What is Porcupine? Where is Porcupine? Definition of Porcupine. Meaning of Porcupine.
		The 11 Old World porcupines are almost exclusively terrestrial, tend to be fairly large, and have quills that are grouped in clusters.
		They separated from the other hystricognaths about 30 million years ago, much earlier than the New World porcupines.
		The 12 New World porcupines are mostly smaller (although the North American Porcupine reaches about 85 cm in length and 18 kilos), have their quills attached singly rather than grouped in clusters, and are excellent climbers, spending much of their time in trees.
	www.knowledgerush.com /kr/encyclopedia/Porcupine (289 words)

	Baruch Undergrad. Honors [2000]: Marcin, R. Comparative: Cranial Anatomy of Rattus...
		· Suborder Hystricognatha: In hystricognathous rodents the masseter inserts in part on a deflected angular process that is mostly lateral to the body of the jaw; this is a derived condition.
		Hystricognaths are only hystricomorphous, but sciurognaths can be protrogomorphous, sciuromorphous, hystricomorphous or myomorphous.
		According to Landry (1957), it is present in both hystricomorphs and nonhystricomorphs and, therefore, cannot be used as a feature to distinguish caviomorphs and Old World hystricognaths from the rest of rodents.
	newman.baruch.cuny.edu /digital/2000/honors/marcin_2000/marcin_2000.htm (5533 words)

	Re: And we think we have it tough...
		Pigs are either hystricognaths or people, not rodents.
		Some researchers choose to elevate the two > suborders within Rodentia to the status of order; under this > scheme, "true" rodents (squirrels, rats, mice, etc.) are > distinguished from so-called "hystricognath" rodents > (porcupines, chinchillas, capybaras, mole rats, guinea pigs, > etc.).
		The distinction is primarily a semantic one, since > both classification schemes acknowledge two major lineages > among the animals known commonly as rodents." > > Ruth B > > > > > --- > Outgoing mail is certified Virus Free.
	www.usenet.com /newsgroups/rec.equestrian/msg03020.html (343 words)

	PlanetSave Blogger
		These specimens have a unique combination of external and craniodental features and are considered members of a new family, genus and species, using comparative morphological and molecular data.
		The disjunct distribution of hystricognaths is recognized as problematic, with most families occurring in the main distributional area of South America, several others in Africa and only one family distributed in Africa and Asia.
		The presence of an additional hystricognath family in Southeast Asia poses interesting questions and consideration is given to the way in which this new taxon fits into the theories of the biogeographical and evolutionary history of other hystricognaths.
	planet-save.com /blogger/blogger.html (3735 words)

	RedNova News - Science - Emerging Themes And Future Challenges: Forgotten Rodents, Neglected Questions (Site not responding. Last check: 2007-10-21)
		Ebensperger (1998) convincingly emphasizes the dangers of theorizing about social evolution of rodents based on limited numbers of species, without taking into account the many temperate and neotropical South American species that appear to be social.
		His attempts to integrate hystricognath rodents into current hypotheses of rodent social evolution already have highlighted the complexity and multifactorial nature of influences that appear to have shaped group living and sociality of Latin American species (Ebensperger 1998, 2001).
		Preliminary evidence suggests that the social system of the white-throated rice rat (Oryzomys albigularis), a species inhabiting the Venezuelan cloud forests, might be comparable to that of Microtus ochrogaster, M. pinetorum, and Peromyscus californicus.
	www.rednova.com /news/stories/2/2003/12/30/story108.html (8132 words)

	SUMMARY (Site not responding. Last check: 2007-10-21)
		As information concerning trophic ecology of mammals of the Monte desert is scarce, fragmentary and frequently only anecdotal, this study aims at determining food resource use by an association of desert mammals.
		This association is composed of small mammals (murid rodents: Graomys griseoflavus, Akodon molinae, Calomys musculinus and Eligmodontia typus ; marsupial: Thylamys pusillus) and medium-sized mammals (hystricognaths: Dolichotis patagonum, Lagostomus maximus, Microcavia australis, Galea musteloides ; exotic lagomorph: Lepus europaeus).
		The hystricognaths and the introduced lagomorph (medium-sized mammals) are herbivores, while the murids and the marsupial (small mammals) behave like omnivores, including seeds, arthropods, and vegetable matter in their diets.
	www.cricyt.edu.ar /INSTITUTOS/iadiza/ojeda/campos.htm (477 words)

	Natural History Collections: Cavy-like Rodents
		Many hystricognaths live in South, Central and North America, e.g.
		Hystricognath skulls are rather angular with very strongly developed incisors.
		The surfaces of the cheek teeth show enormous variation in pattern and complexity among different species.
	www.nhc.ed.ac.uk /index.php?page=24.134.166.171.193.197 (159 words)

	Degu origin
		It's worth pointing out that degus can be referred to as (New World) rodents, hystricognaths, hystricomorphs, caviomorphs, octodontids and octodonts.
		In particular, the Hystricognath group includes the degus' close relatives the wild Guinea pig
		Hystricognaths have 230 species in 68 genera and 17 families
	www.btinternet.com /~p.long/degutopia/degufam.htm (464 words)

	New Rident Discovered at Asian Food Market (Site not responding. Last check: 2007-10-21)
		The research suggests the kha-nyou is a "living fossil" that split from other rodents many millions of years ago.
		The rodent also seems to be an ancestor of the hystricognaths, a group of rodents that is spread across the globe and includes porcupines, African mole rats, guinea pigs, and chinchillas.
		Until now, the last mammal family to be discovered was that of the bumblebee bat—the world's smallest known mammal.
	www.ngnews.com /news/2005/05/0516_050516_new_rodent.html (1024 words)

	Mesozoic Mammalia - GCR block
		Most of these are myomorphs — mice, rats and their relatives — a group that radiated explosively in the past 20 million years.
		Other rodent groups include the sciuromorphs (squirrels and beavers) and the hystricognaths (guinea pigs, capybaras and chinchillas), a group restricted to South America.
		The Lagomorphs — rabbits and hares — are close relatives of the rodents, as probably are the Macroscelidea, the elephant shrews of Africa.
	www.jncc.gov.uk /earthheritage/gcrdb/GCRblock.asp?block=48 (2040 words)

	TAXACOM archives -- October 1999 (#198) (Site not responding. Last check: 2007-10-21)
		However, I still have seen no strong evidence to counter the prevailing view that rodents and lagomorphs are sister groups.
		If this were indeed the case, the only logical remedy would be to split the rodents into two orders (sciurognaths and hystricognaths).
		My initial study of the actual gene sequences (upon which the 1996 Nature article is based) seems to show no really hard evidence for rodent paraphyly (although statistically suggestive enough that it merits a little closer look).
	listserv.nhm.ku.edu /cgi-bin/wa.exe?A2=ind9910&L=taxacom&D=1&O=D&P=20203 (344 words)

	Babel \| Paleontology of Porcupines
		Our results indicate a basal trifurcation of hystricognaths leading to Hystricidae, Phiomorpha s.s.
		As everyone knows, porcupines are quill bearing rodents that can cause pain to attackers.
		It presents many ancestral characters, but their predecessors are unknown and the earliest fossils are recorded only since the early Miocene of Europe (Mackenna and Bell, 1997).
	towerofbabel.com /map/articles/05/03/11/0334251.shtml?tid=269 (702 words)

	The Biology Refugia: New mammal family from Laos
		Abstract - During biodiversity surveys in Khammouan Province, Lao Peoples Democratic Republic, specimens of an unknown species of hystricognathous rodent were discovered in local markets being sold for food; local hunters explaining that these rock rats were trapped in the nearby limestone karst.
		The results of the molecular and morphological analyses are compared and provide the basis for a discussion of relationships of the new taxon within the Rodentia and Hystricognatha.
		The disjunct distribution of hystricognaths is recognised as problematic, with most families occurring in the main distributional area of South America, several others in Africa and only one family distributed in Africa and Asia.
	staff.science.nus.edu.sg /~sivasothi/biorefugia/2005/05/new-mammal-family-from-laos.html (293 words)

	3.16 Rodents
		Neotropical hystricognaths and caviomorphs, 126 species according to Mares and Ojeda (361), occupy a vast range of ecological niches and habitats.
		Some reach considerable sizes, and they constitute a major and highly specific item among the Latin American game animals, particularly in their contribution to the diet.
		Whether or not captive breeding is profitable depends very much on the whims of fashion, this being what determines world market prices for furs.
	www.fao.org /docrep/T0750E/t0750e0o.htm (5902 words)

	Molecular Systematics
		In sciuromorphs (squirrel-like rodents, gophers, and beavers) part of the lateral masseter has shifted onto the rostrum.
		Hystricomorphs (hystricognaths, jumping mice, springhare, and gundis) have the medial masseter originating on the rostrum and passing through an enlarged infraorbital foramen.
		Finally, in myomorphs (most rats and mice, dormice) the anterior part of the lateral masseter originates on a special projection of the zygomatic arch and the anterior part of the medial masseter passes through an enlarged infraorbital foramen.
	www.bio.umass.edu /biology/adkins/Systematics.html (2783 words)

	Rat Genome Database: References
		The 10 rodent families studied here cluster in five clades: Hystricognathi, Sciuridae and Aplodontidae (Sciuroidea), Muridae, Dipodidae, and Gliridae.
		Among hystricognaths, the following conclusions are drawn: a single colonization event in South America by Caviomorpha, a paraphyly of Old World and New World porcupines, and an African origin for Old World porcupines.
		Despite a broader taxonomic sampling diversity, we did not obtain a robust answer to the question of Rodentia monophyly, but in the absence of any other alternative, we cannot reject the hypothesis of a single origin of rodents.
	rgd.mcw.edu /tools/references/references_view.cgi?id=634526 (277 words)

	Zoo Tek Forums -> The Zoo Tek Nature Encyclopedia (Site not responding. Last check: 2007-10-21)
		Bit more stuff in ZTNE tonight.More of the colubrid snakes (this is going to be a long job) plus prehistoric coypu,agoutis and hutias.
		All the prehistoric hystricognaths are now in ZTNE
		Well, as one of the websites I use for reptile listings is down I've been unable to add any more snakes today.However,as my two other sources of animal listings are okay,I've added a mixed bag of prehistoric rodents and frogs and toads.
	www.zoo-tek.com /forums/index.php?showtopic=4371&st=45 (377 words)

	Nat' Academies Press, Biodiversity II: Understanding and Protecting Our Biological Resources (1997)
		Thus, they provide a benchmark against which the utility of new character sets can be assessed.
		These groups include tetrapods and their subgroups, the Amniota and Mammalia (Benton, 1990); within mammals, Artiodactyla (cow and pig) and rodents; and within rodents, the subgroups hystricognaths (guinea pig) and myomorphs (rat and mouse, hamsters) (Luckett and Hartenberger, 1985).
		There is evidence that guinea pigs may not be rodents (Graur et al., 1991).
	www.nap.edu /openbook/0309052270/html/305.html (1008 words)

	Rodent Phylogeny and a Timescale for the Evolution of Glires: Evidence from an Extensive Taxon Sampling Using Three ...
		Catzeflis F. Hänni, P. Sourrouille, E. Douzery, 1995 Molecular systematics of hystricognath rodents: the contribution of sciurognath mitochondrial 12S rRNA sequences Mol.
		DeBry R. Sagel, 2001 Phylogeny of Rodentia (Mammalia) inferred from the nuclear-encoded gene IRBP Mol.
		Huchon D., E. Douzery, 2001 From the Old World to the New World: a molecular chronicle of the phylogeny and biogeography of hystricognath rodents Mol.
	mbe.oupjournals.org /cgi/content/full/19/7/1053 (6741 words)

	RedNova News - Science - Ecology Of Sociality In Rodents: A Ctenomyid Perspective (Site not responding. Last check: 2007-10-21)
		Ebensperger (2001) also reviewed hypotheses to explain group living and, on the basis of an extensive literature survey, concluded that benefits of natal philopatry as well as constraints on natal dispersal contribute to rodent sociality.
		Taking a more quantitative approach, Ebensperger and Cofre (2001) examined 3 hypotheses regarding group living among New World hystricognaths using the method of independent contrasts; these authors concluded that reduction of burrowing costs provided the best explanation for the taxonomic distribution of sociality in these animals.
		CROOK, J. Social organization and the environment: aspects of contemporary social ethology.
	www.rednova.com /news/stories/2/2003/12/30/story105.html (6987 words)

	Monophyly of the order Rodentia inferred from mitochondrial DNA sequences of the genes for 12S rRNA, 16S rRNA, and ...
		hystricognath rodents, such as the guinea pig, represent an independent
		(107 mya) for the divergence of sciurognaths and hystricognaths.
		biochemical properties of some hystricognath metabolic proteins, largely
	mbe.oupjournals.org /cgi/content/abstract/12/1/168 (424 words)

	COLONIALIDAD EN EL ROEDOR OCTODON DEGUS: UNA PRUEBA MULTIPLE DE HIPOTESIS.
		SOCIALITY IN RODENTS: THE NEW WORLD FOSSORIAL HYSTRICOGNATHS AS STUDY MODELS.
		ON THE EVOLUTION OF GROUP-LIVING IN THE NEW WORLD CURSORIAL HYSTRICOGNATH RODENTS.
		ON THE EVOLUTIONARY CAUSES OF SOCIALITY IN THE NEOTROPICAL HYSTRICOGNATH RODENTS: A COMPARATIVE ANALYSIS.
	www.conicyt.cl /bases/fondecyt/proyectos/03/1997/3970028.html (278 words)

	ITIS Standard Report Page: Echimyidae (Site not responding. Last check: 2007-10-21)
		This group is complex, and in need of revision.
		The family includes the most primitive fossil New World hystricognaths from the Early Oligocene of Patagonia
		Additional off-site resources may be available for this taxon.
	www.itis.usda.gov /servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=584583 (134 words)

	Degu Health
		This suggests there is/was some form of evolutionary pressure on blood glucose hormones in caviomorphs
		It has been shown that the Hystricognaths as an order have a highly divergent insulin structure
		In fact, degu insulin is only 1-10% active in controlling blood sugar levels compared to other mammals
	www.btinternet.com /~p.long/degutopia/deguhealth.htm (1312 words)

	Degu Appearance
		It is interesting to note that the musculature of the degu is consistent with all other hystricognaths, but is not found in any other rodent group
		The brain of the degu is reported to follow the general pattern of rodents, but the olfactory bulb (that used to distinguish smells) is particularly well developed
		It has been reported that (with a few exceptions) the degus cephalic arteries are identical to other hystricognaths
	www.btinternet.com /~p.long/degutopia/deguapps.htm (1839 words)

	'Oddball Rodent' Is Called New to Science (Site not responding. Last check: 2007-10-21)
		Key Words: new family; new genus; rodents; hystricognaths; 12S rRNA; cytochrome b; comparative morphology.
		specimens of an unknown species of hystricognathous rodent were discovered in local markets being sold for food;
		So in other words, these were common as squirrels, routinely sold as food.
	www.freerepublic.com /focus/f-news/1401960/posts (2373 words)

	Order Lagomorpha
		New World hystricognaths to have developed highly fossorial
		There are three hystricognath families that we also lack specimens of.
		We actually do have this skull of a caviid - a large relative of the guinea pig.
	www.bioweb.uncc.edu /biol4235-5235/Lagos%20&%20rodents.htm (1024 words)

	Molecular Phylogeny and Divergence Time Estimates for Major Rodent Groups: Evidence from Multiple Genes -- Adkins et ...
		GHR sequences, monophyly is supported, with the estimated divergence
		between hystricognaths and most sciurognaths dating to about
		Most estimated dates of divergence are consistent with
	mbe.oxfordjournals.org /cgi/content/abstract/18/5/777 (805 words)

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