By David Dyer, Natural History Curator
INTRODUCTION
Every 12 months Ohioans discover tooth from a wide range of giant mammal species. These typically wash out of the banks of streams or rivers, are uncovered when excavating for a pond or drainage tiles, or often are discovered on the floor of the bottom. Enamel is a really laborious substance, and tooth will typically survive after changing into separated from the cranium or jaw and even after the bone has eroded away. Teeth are comparatively straightforward to establish in contrast to fragmented skeletal stays, and this will permit us to decide what species are current in the state right this moment and from Ohio’s Ice Age previous.
This information will present you info on the number of tooth which might be discovered in the state, and hopefully provide help to establish what you’ve discovered. A observe of warning although: If you discover the tooth of an extinct mammal similar to mastodon or mammoth in the bottom in its unique place, contact a museum or college geology division earlier than eradicating it. This will assist to protect any info that may be realized from the sediments it’s preserved in. Though enamel is a tough substance it may also be brittle and eradicating a tooth from the bottom may trigger it to crumble.
For extra info on gathering pure historical past objects, together with related authorized points, see my earlier weblog publish “What is it? – Identification of Natural History Objects” right here.
NO DINOSAURS IN OHIO!
Often when massive tooth or bones are discovered, it’s straightforward to leap to the conclusion that they should be from a dinosaur. But no dinosaur stays have ever been discovered in Ohio. In truth, the rocks that may include dinosaur stays have been both by no means deposited in Ohio or have lengthy since eroded away.
But we have now a tremendous range of different fossils in the state. Ohio has ample invertebrate fossils from a lot of the Paleozoic Era, which dates from about 540 to 250 million years in the past. We even have a wealthy document of fossils from the Pleistocene epoch (the newest Ice Age) courting from about 11,600 years in the past and older.
A geologic cross-section of the earth. Rocks from the Triassic by means of the Pliocene will not be discovered in Ohio.
WHAT IS NOT A TOOTH
Before we take a look at the number of mammal tooth that may be discovered in the state, let’s take a look at some issues which might be not tooth however may be simply mistaken for them. Due to their tooth-like form, fossil horn corals are sometimes mistaken for tooth. These are a bunch of solitary corals that lived in the Paleozoic seas and one animal (polyp) lived in every horn-shaped skeleton. Horn corals may be distinguished from mammal tooth by their outer wrinkled floor and by the distinctive inside ridges, known as septa, clearly seen on the broad finish of the skeleton. Also, horn corals are mineralized due to their nice age in the a whole lot of tens of millions of years whereas the fossil mammals discovered in Ohio are in the 1000’s of years outdated – not almost sufficiently old to turn out to be this mineralized.
A horn coral from Ohio, Zaphrentis.
Another Ohio horn coral, Streptelasma.
Rocks or minerals may break down and climate till they intently resemble animal tooth. In the primary instance beneath, the rock was damaged in such a approach that the underside half seems just like the bone of a jaw and the lighter mineral above has pointed edges that resemble tooth. The second specimen is the mineral calcite, and the form resembles a tooth. I used to be certain each of those have been tooth till I picked them up! But in each instances there isn’t any construction that might be discovered on a tooth, similar to enamel, dentin or roots.
It’s not tooth, only a rock!
This is a mineral, not a tooth.
ANATOMY OF A TOOTH
Before persevering with, let’s take a look at the construction of a tooth. The phrases right here will probably be used in the descriptions of the tooth in the subsequent part. A typical tooth has two essential elements: 1) a crown, consisting of enamel over a softer bone-like materials known as dentin and a couple of) roots, made up of dentin coated by a skinny layer of cementum, which acts to assist anchor the tooth in the bony socket. The chewing floor on the crown of a tooth is known as the occlusal floor. The gumline is the place the highest of the gums could be in a dwelling animal. Cheekteeth primarily refers to the premolars and molars, which run alongside the cheek as opposed to the canines and incisors that are in the extra anterior a part of the mouth. The time period anterior means in direction of the entrance of the mouth whereas posterior means in direction of the again of the mouth.
Anatomy of a tooth (Wikimedia Commons).
EXAMPLES OF LARGE MAMMAL TEETH
If you’re feeling that what you discovered is almost definitely a tooth and never one of many imitators, and also you’re acquainted with the essential elements of a tooth, let’s check out the number of giant mammal tooth, beginning with the most important. This is a quick overview of the widespread, bigger tooth which might be probably to flip up in Ohio. Note that there may be broad variation in the looks of a tooth inside a species, relying on age, put on, eating regimen, and particular person variation. If in doubt, contact a museum or college for help.
Mammoths (Mammuthus sp.) roamed Ohio close to the top of the Pleistocene interval, together with their distant cousin the mastodon. Mammoths have been grazers, feeding on grasses and sedges, and their tooth mirror their specialised eating regimen. The enamel seen on the occlusal floor of their tooth is organized in rows of plates that reach down by means of the tooth to the roots. This gives a tricky grinding floor for processing coarse silica-rich grasses and is a really long-lasting tooth floor. No different giant tooth may have this distinctive sample of enamel ridges.
Woolly Mammoth – Mammuthus primigenius. Upper molar.
Mastodon (Mammut americanum) tooth have cone-shaped cusps coated with enamel, excellent for his or her looking eating regimen of leaves, twigs, spruce cones, and even aquatic vegetation. Note that the enamel masking on the tooth is on the crown solely and doesn’t prolong down by means of the tooth as in mammoths. The cusps in mastodon tooth will turn out to be extra flattened because the tooth wears down with use.
American Mastodon – left higher third molar.
American Mastodon – occlusal view of the crown (roots lacking) of left higher third molar. Note the conical formed susps.
Horses (Equus sp.) lived in Ohio through the Ice Age however have been extirpated from North America shortly after the glaciers left. They have been then reintroduced to North America by Europeans at about 1500. Horses have high-crowned (hyposodont) premolars and molars. This implies that the crown of the tooth is excessive and extends nicely beneath the gumline, an adaptation for a grazing eating regimen. The crowns of horse cheek tooth have a tendency to be extra sq. or rectangular in form. Another distinctive trait in horse tooth is a sophisticated enamel sample of raised enamel ridges (lophs) of which some are oriented transversely throughout the crown floor.
Horse – Equus caballus. Upper proper toothrow; anterior is to the precise.
Horse – Equus caballus. Toothrow of left mandible; anterior is to the left.
Horse – higher left molar/premolar. Note the excessive crown and sq. form of the tooth. Scale is in centimeters.
Cattle (Bos taurus) and bison (Bos bison/Bison bison) are very related morphologically so we received’t try to separate the species in this information. Bison lived in Ohio from the Ice Age till concerning the 12 months 1800, and cattle have been launched to North America by Europeans. Keep in thoughts that most finds in Ohio of such tooth are from fashionable cattle, due to the big variety of cattle which have lived in the state for 200+ years. However some bison stays have been discovered. Cattle and bison even have high-crowned (hypsodont) cheek tooth, though the form of the tooth is far completely different than in the horse. Note that the cusps in cattle and bison seem as a collection of crescents (selenes) when viewing the chewing floor. This is called a selenodont crown sample.
Upper left toothrow of home cow; anterior is to the left. This specimen is from a younger particular person and the final molar (third molar) has not erupted but.
Toothrow of proper mandible of home cow; anterior is to the precise.
Domestic cow – decrease left third molar. Note the high-crown, and the accent cusps that are seen on some cattle and bison molars. Scale is in centimeters.
Elk (Cervus canadensis) lived in Ohio from Ice Age occasions till about 1850, and elk stays are nonetheless often discovered in the state. However you’re more likely to discover tooth of White-tailed Deer (Odocoileus virginianus), a standard species throughout Ohio. Deer and elk are each in the deer household (Cervidae) and have low-crowned (brachyodont) molars and premolars. This implies that the crown is decrease and stops on the gumline. We’ll illustrate deer tooth right here, however elk tooth could be very related solely bigger. Deer and elk even have a selenodont crown sample as we noticed above in cattle and bison. Sometimes very worn tooth of elk and cattle/bison may be troublesome to inform aside.
White-tailed Deer – higher left toothrow; anterior is to the precise.
White-tailed Deer mandible; anterior is to the precise.
Pig or Wild Boar (similar species: Sus scrofa) have molars and premolars with low rounded cusps, known as bunodont tooth, and are helpful for crushing meals. Pig tooth are probably the most widespread varieties of tooth that we’re requested to establish. Pigs have a posh and really distinctive crown sample which helps to establish them. Bunodont dentition is mostly discovered in omnivores, animals which have a assorted eating regimen of many varieties of meals. Bunodont cheekteeth are additionally discovered in raccoons, bears, and sure, in people too!
Upper toothrows of a pig; anterior is to the left. Note that the primary left premolar is lacking.
Pig – toothrows of the mandible; anterior is to the left.
Upper canine (“tusk”) of a pig. Scale is in centimeters.
Black bears (Ursus americanus) have been widespread in Ohio from the Ice Age till about 1850, after they have been extirpated from the state. However in current years black bears have been returning to Ohio. As talked about above, bears even have bunodont cheekteeth with low rounded cusps. They even have giant higher and decrease canines that are distinctive.
Black Bear – proper lateral view of higher toothrow.
Black Bear mandible.
All pictures credit score Ohio History Connection.
MORE OHIO SPECIES
We couldn’t cowl each doable mammal species that may happen in Ohio however it is a good beginning place. Here are some species to concentrate on, each extirpated and extinct, that we didn’t embrace however all are a lot much less widespread than the opposite species in this weblog.
Grizzly Bear (Ursus arctos) – cranium and tooth related to black bear however bigger; one Pleistocene document from Ohio.
Giant Short-faced Bear (Arctodus simus) – current in Ohio through the late Pleistocene and is commonly described as the most important land carnivore in Ice Age North America; one Pleistocene document from Ohio.
Gray Wolf (Canis lupus) – lived in Ohio from Ice Age till about 1850.
Dire Wolf (Aenocyon dirus) – tooth related to the grey wolf, however somewhat bigger. However, the carnassial tooth (enlarged pair of a decrease molar and higher premolar for shearing meat) in the dire wolf are a lot bigger. One Pleistocene document from Ohio.
Muskox (Ovibos moschatus) and the extinct Woodland Muskox (Bootherium) – each species have been discovered in Ohio in the Ice Age; tooth could be considerably related to cattle or bison.
Caribou (Rangifer tarandus) – lived in Ohio in Ice Age and tooth related to deer or elk.
Stag-moose (Cervalces scottii) – a big Ice Age relative of the fashionable elk, with tooth related to elk.
Flat-headed Peccary (Platygonus compressus) – Ice Age pig-like species however its cheekteeth had increased cusps than in pigs, for an omnivorous eating regimen together with looking on coarse vegetation; higher canines are straight and level downward reasonably than curved like pig/wild boar.
Jefferson’s Ground Sloth (Megalonyx jeffersonii) – an uncommon Ice Age species with giant peg-like cheekteeth.
Giant Beaver (Castoroides ohioensis) – cranium and cheekteeth very related in look to the fashionable beaver however a lot bigger; had very giant incisors.
For extra info:
Animal Skulls: A Guide to North American Species – by Mark Elbroch, 2006. Stackpole Books.
Mammal Bones and Teeth: An Introductory Guide to Methods of Identification – by Simon Hillson, 2009. Institute of Archaeology Publications, University College London.
A Key to the Skulls of North American Mammals (4th Edition) – by Monte Thies, 2015. Kendall Hunt Publishing.
Animal Diversity Web, University of Michigan:
Includes a lot of cranium pictures, and a piece on mammal tooth: collections/mammal_anatomy/tooth_introduction/
