The grrrr…izzly bear enters the LRT

Distinct in skull shape
from the polar bear (Ursus maritimus), the grizzly bear (Ursus arctos) (Fig. 1) had me wondering if perhaps it would nest with dogs like Canis in the large reptile tree (LRT, 1417 taxa). After all there are such things as bear-dogs (genus: Amphicyon). We also looked at the short-face bear (genus: Arctodus) derived from the wolverine (genus: Gulo).

Figure 1. Ursus arctos, the grizzly bear, nests with Ursus maritimus, the polar bear in the LRT, as expected.

Figure 1. Ursus arctos, the grizzly bear, nests with Ursus maritimus, the polar bear in the LRT, as expected.

Alas, U. arctos nested with U. martimus.
Both are bears. Both are derived from mink-weasels like Mustela (extant) and sea weasels like Puijila (Late Oligocene) + Neotherium (Middle Miocene), not dogs.

Ursus arctos (Linneaus 1758 ; up to 3m in length) is the extant grizzly bear. It has a deeper face than U. maritimus, yet nests as a sister taxon here.

Figure 2. Skull of Ursus maritimus, the polar bear. It's worthwhile noting the similarities and differences, which are more distinct than just the colors of their furry coats.

Figure 2. Skull of Ursus maritimus, the polar bear. It’s worthwhile noting the similarities and differences, which are more distinct than just the colors of their furry coats.


References
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

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