Hyaenodon

Hyaenodon [Brule Formation, Pennington County, South Dakota]

The genus Hyaenodon contained carnivorous mammals that lived from the Eocene Epoch 42 million years ago until extinction during the Oligocene Epoch 25 million years ago. There so far are records of at least 30 species with fossils found in Asia, Africa, Europe, and North America. Hyaenodon means "hyena-toothed" as these animal had large, sharp teeth for their carnivorous diet.

Teeth of the Hyaenodon

During their existence, Hyaenodon was a dominant predator. The species ranged in size from small and fox-like to others as large as rhinos. It is believed the smaller species hunted in packs, likely at night, whereas the larger species likely hunted alone. Extinction of the order Creodonta, of which Hyaenodon belongs, possibly came from competition with Carnivora, the order most carnivores belong to in modern times.

From the newest fossil collection at the Heard Natural Science Museum and Wildlife Sanctuary.

Merycoidodon

Merycoidodon cuibertsoni [White River, Dawes County, Nebraska]

Related to camels, sheep, and pigs, Merycoidodontidae were mammals that once roamed North America 34 million years ago until their extinction 5 million years ago during the Tertiary Period. Their teeth contained long-lasting grinding surfaces well adapted for effective side to side chewing. They were about 1.2 m (4 ft) in length with a heavy build similar to modern day pigs. Fossils of Merycoidodon have most often been found in large numbers in small areas pointing towards the likelihood of these creatures having lived in herds.

From the newest fossil collection at the Heard Natural Science Museum and Wildlife Sanctuary.

Prairie Ring-necked Snake

Hatchling Prairie Ring-Necked Snake, Diadophis punctatus arnyi

The Prairie Ring-Necked Snake, a subspecies of ring-necked snake, is a small, non-venomous snake. They range in size between 25-38 cm (10-15 in) and have a distinctive orange or yellow neck band as well as an orange or yellow belly. Although found throughout the eastern two thirds of the United States up into Canada and down into Mexico, they are secretive. Ring-necked snakes prefer rocky, wooded hillsides for shelter and to search for prey. Their main diet consists of worms, slugs, other soft-bodied insects, and small reptiles. These snakes do not reach sexual maturity until the third year and are thought to have a lifespan close to 20 years in the wild. They rarely venture out during the day and have a single denning site.

Labor Day

Due to some technical difficulties, there will be no post today. Hope you had a great Labor Day Weekend!

Mastodon

Molars of Mammut americanum, Oklahoma.

Related to elephants and extinct for close to 11,000 years, mastodons were one of the megafauna that once inhabited North America. They were similar to modern elephants with large, curved tusks and corrugated grinding surfaces of the teeth, but they were also similar to mammoths with their shaggy hair. Remains of mastodons were first discovered in 1705 when a tenant farmer discovered a five-pound tooth. More teeth were discovered in other parts of North America until a French anatomist finally gave mastodons a name. The common name was based on the teeth as the conical cusps resembled breasts: mastos (Greek for breast) and odont (for tooth). Although the shape of the tooth first gave thought to flesh-eating beasts, it has since been concluded that the shape of the teeth provided best for browsing and grazing.

From the newest fossil collection at the Heard Natural Science Museum and Wildlife Sanctuary.

Sharks

Fossilized Shark Tooth

Sharks have been in existence since at least the Ordovician Period over 450 million years ago. This was during the time of vast marine diversity, and little diversity present on land. One of the earliest representations of sharks discovered was Cladoselache, which differs in form from modern sharks, but was still a high-speed predator. The most common discovery related to ancient sharks are their fossilized teeth. As sharks shed thousands of teeth throughout their lifespan, there is a higher chance for one of these teeth to find the right conditions for fossilization; however this often presents a problem of identification. In addition to scattered and mixed teeth findings, many sharks exhibit dignathic heterodonty, or a difference in the upper and lower teeth in addition to parasymphyseal, or a difference in teeth in relation to jaw position. Gender difference are also often translated to the teeth making it hard to identify the species a shark tooth originated from.

From the newest fossil collection at the Heard Natural Science Museum and Wildlife Sanctuary.

Lynx Spiders

Lynx Spider, Oxyopes acleistus

Lynx spiders of the family Oxyopidae are found throughout the world, particularly in the tropics and subtropics. These spiders are active, roving hunters often using foliage for camouflage to ambush prey. Some species can jump up to 2 cm (.79 in) in the air to catch insects in flight. Although lynx spiders usually do not build webs, there are exceptions. These spiders are also very protective of their eggs, and often die of starvation due to this behavior.