Examples of using Dirus in English and their translations into Polish
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Guildayi weighed on average 60 kilograms(132 lb) and C. d. dirus was on average 68 kg 150 lb.
Canis lupus and Canis dirus compared by mean mandible tooth measurements millimeters.
Nowak, Kurten, andAnnalisa Berta proposed that C. dirus was not derived from C. lupus.
The largest C. d. dirus femur was found in Carroll Cave, Missouri, and measured 278 mm 10.9 in.
Two subspecies are recognized: Canis dirus guildayi and Canis dirus dirus.
Canis dirus guildayi compared with the Yukon wolf by the mean length of limb bones in millimeters inches.
In 2010 Francisco Prevosti proposed that C. dirus was a sister taxon to C. lupus.
The fossil record shows them as rare andit is assumed that they could not compete with the newly derived C. dirus.
For this reason, some researchers have proposed that C. dirus may have originated in South America.
By 1912 he had found a skeleton sufficiently complete to be able to formally recognize these andthe previously found specimens under the name C. dirus Leidy 1858.
The fossil record suggests C. dirus originated around 250,000 YBP in the open terrain of the mid-continent before expanding eastward and displacing its ancestor C. armbrusteri.
In 1857, while exploring the Niobrara River valley in Nebraska,Leidy found the vertebrae of an extinct Canis species that he reported the following year under the name C. dirus.
Guildayi is estimated to have weighed on average 60 kg(130 lb), andC. d. dirus weighed on average 68 kg(150 lb) with some specimens being larger, but these could not have exceeded 110 kg(240 lb) due to skeletal limits.
In 1876 the zoologist Joel Asaph Allen discovered the remains of Canis mississippiensis(Allen 1876) andassociated these with C. dirus(Leidy 1858) and Canis indianensis Leidy 1869.
The major fossil-producing sites for C. d. dirus are located east of the Rocky Mountains and include Friesenhahn Cave, near San Antonio, Texas; Carroll Cave, near Richland, Missouri; and Reddick, Florida.
Because the rules of nomenclature stipulated that the name of a species should be the oldest name ever applied to it, Merriam therefore selected the name of Leidy's 1858 specimen, C. dirus.
The majority of fossils from the eastern C. d. dirus have been dated 125,000-75,000 YBP, but the western C. d. guildayi fossils are not only smaller in size but more recent; thus it has been proposed that C. d. guildayi derived from C. d.
Although some studies have suggested that because of tooth breakage, the dire wolf must have gnawed bones and may have been a scavenger, its widespread occurrence andthe more gracile limbs of C. d. dirus indicate a predator.
One study found that C. dirus was the most evolutionarily derived Canis species in the New World, and compared to C. nehringi was larger in the size and construction of its lower molars for more efficient predation.
Nowak later referred to this material as C. armbrusteri; then, in 2009, Tedford formally published a description of the specimens and noted that,although they exhibited some morphological characteristics of both C. armbrusteri and C. dirus, he referred to them only as C. dirus.
The following year, a study yielded evidence that led to the conclusion that C. dirus and C. nehringi were the same species and thus that C. dirus had migrated from North America into South America, making it a late participant in the Great American Interchange.
Geographic differences in dire wolves were not detected until 1984, when a study of skeletal remains showed differences in a few cranio-dental features and limb proportions between specimens from California and Mexico(C. d. guildayi) andthose found from the east of the Continental Divide C. d. dirus.
Fossil specimens of C. dirus discovered at four sites in the Hay Springs area of Sheridan County, Nebraska,were named Aenocyon dirus nebrascensis(Frick 1930, undescribed), but Frick did not publish a description of them.
Gloria D. Goulet agreed with Martin,proposing further that this hypothesis might explain the sudden appearance of C. dirus in North America and, judging from the similarities in their skull shapes, that C. lupus had given rise to the C. dirus hypermorph due to an abundance of game, a stable environment, and large competitors.
In 1984 a study by Björn Kurten recognized a geographic variation within the dire wolf populations and proposed two subspecies:Canis dirus guildayi(named by Kurten in honor of the paleontologist John E. Guilday) for specimens from California and Mexico that exhibited shorter limbs and longer teeth, and Canis dirus dirus for specimens east of the North American Continental Divide that exhibited longer limbs and shorter teeth.