Search the Community
Showing results for tags 'astragalus'.
Found 4 results
Edit to add: more likely a phalange This was found in the river at the confluence of the Blue Earth and Minnesota River in South Central Minnesota on August 3, 2018. It appears to me to be an astragalus, the size of that of a white tailed deer, but the shape is not quite right. It matches none of the astragali found in Miles Gilbert's Mammalian Osteology. The "bump" at about the 4cm mark in two of the photos seems like a very distinctive feature, yet I cannot find an identification for this. About our area: This area was, in early American times, the land of the Sioux Indians and the bison. Geologically, this area is very rich in silica. We find a lot of mineralized bones of bison, bos, Odocoileus virginianus, etc. This is the north eastern edge of the great plains.
Horse Teeth 'Modern' horse teeth are very hypsodont (high-crowned) to deal with wear caused by eating gritty and/or fibrous foods like grasses. A mature horse may have as many as 44 teeth, which include: 12 incisors (6 upper and 6 lower) Canine teeth are usually absent in female horses but may be present in males. Cheek teeth (4 premolars and 3 molars per side) have very complex enamel patterns. The first premolars (upper and lower) in horses (sometimes called the 'wolf teeth') are vestigial and often absent. Upper cheek teeth (premolars and molars) can be recognized by the relatively square shape (except for the second premolar and third molar) when viewing the occlusal (chewing) surface. Lower cheek teeth (premolars and molars) can be recognized by the relatively rectangular shape when viewing the occlusal (chewing) surface (except for the second premolar and third molar). Horse 'foot' bones 'Modern' horses are monodactyl (one-toed). The metapodials (hand and foot bones) are reduced to a single unit on each leg. There are three 'toe bones' - phalanges (singular is phalanx) on each foot...phalanx I, phalanx II and phalanx III. The third phalanx is the 'hoof core' Unfortunately, I have never collected an intact phalanx III so I have not pictured one here. The astragalus (ankle bone) is only present on the hind legs.
Hi people! A friend of mine collected the astragalus of the photo from a fossiliferous site with Pleistocene mammals in southern Brazil. Although we have a large collection of fossils at the university, we couldn't identify it. We have already excluded horses, tapirs, ground sloths, sabertooth cats...could it be a bear or possibly a mastodont?