Vertebrate Fossil Identification Along the Chesapeake Bay - Maryland and Virginia - Calvert Cliffs

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Fossil Miocene Vertebrates from the Chesapeake Bay, Maryland - Examples and Identification

Besides the countless shark fossils found in the Miocene deposits of the Chesapeake bay, other vertebrates are also found. The Miocene seas were home to numerous Cetacea (whale and dolphin type animals), Seals, Turtles, Salt water Crocodiles, and even Manatees. Some of the cetacea include the bizarre Squalodon, who had a primitive form of echolocation, and still retained a land mammal dentition. Others include some of the first baleen whales, the great plankton feeders.

Besides for the marine vertebrates, fossilized remains of land animals are also sometimes found. These are from the short time periods when the sea levels regressed. Land animals would live on the land. When the waters would rise again, sometimes the remains of these land animals would fossilize. They are rarely found scattered in thin layers of the Calvert Cliffs.
Based on the fossil finds, this area was much warmer than today. Animals that one wouldn't think of are found here, from the common Peccaries, to Camels, Llamas, Rhinocerases, Mastodons, Wolves, and even animals like the strange Bear Dog lived here.

For Identification of ALL fossils, and not just vertebrates, found at the Calvert Cliffs, Click Here. Click on the following links for Fossil Sharks, and Fossil Invertebrates from the Calvert Cliffs.


Click on the image to go to the specific type of fossil, or scroll down to browse.

Vertebrate Fossils (Besides Sharks) Found in the Calvert & Choptank formations at the Calvert Cliffs of Maryland

Fish Fossils - Rays, and Bony Fish


Eagle Ray
Aetomylaeus sp.

Bonnet Ray
Aetobatis sp.

Sturgeon
Acipenser sp

Tarpon
Megalops sp.
Reptile Fossils From Calvert Cliffs

Salt Water Crocodiles
"Thecachampsa" sp.


Sea Turtles
Syllomus aegyptiacus
Marine Mammals: Seals, Odontocete Cetaceans - Toothed Whales, Mysticeti - Baleen Whales

Seal
Phocidae sp.

Shark Toothed Whale
Squalodon sp.

Odontocetes
Toothed Whales,
Including Dolphin type animals

Baleen Whales
Balaenopteroidea Family



Myliobatiformes order
(Rays)


Rays are related to Sharks and Skates, as they are all in the Chondrichthyes Class. Fish in this class have a skeleton made of cartilage instead of true bone. What this means for the fossil collector is bones from these animals seldom fossilize. Occasionally a vertebra may be found, however mostly the hard shark teeth and ray crushing plates are found.


Myliobatidae family
(Eagle Rays)

Today, the bay is home to the Cownose Ray (Rhinoptera bonasus), an Eagle Ray which can get as large as 3 feet in length. If you are boating, or snorkeling, you can sometimes catch them basking in the sun near the surface of the water. Here, we were visited by a large one while snorkeling

In the Calvert & Choptank Sea, there was a wide array of genus of Eagle Ray in the bay, that included many tropical forms not found here today.
As a result, identifying crushing plate fragments commonly found on the beaches are very difficult. Some of the common genus include Aetobatis (Bonnet Rays), Aetomylaeus (Smooth-tail Eagle Rays), Myliobatis (Eagle Rays), and Rhinoptera (cownose rays) which inhabit the bay today.

Ray crushing plates

Rays have modified teeth that form flat crushing plates. These crushing plates are adapted for eating mollusks and crustaceans on the sea floor. They suck their prey up like a vacuum and simply crush them between their upper and lower crushing plates.

Most Ray fossils found are tiny fragments of these crushing plates. These fragments can sometimes be difficult to identify to a genus level.

Aetomylaeus sp.
(Smooth-tail Eagle Ray partial crushing plate)
This plate came from a large species of Aetomylaeus, which was probably around 6 - 7 feet in width.

Partial crushing plates, like this one, are very difficult to find due to their fragile nature. Amy found this one still in a big clay pebble, probably from Zone 9. A piece of the pebble was missing. This missing part contained the rest of the plate! We figure another collector saw the plate piece in the pebble fragment, and took it without noticing the rest of the plate in the rest of the pebble.

Here are some pics of it when it was found in the pebble.

The left view is the side that did the crushing, the right is the back side of the plate

Formation:
  • Calvert, Plum Point member, Zone 9
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • South of Brownies Beach, Calvert Co., MD
    Size:
  • ~ 3.5 x 2" (88 x 50mm)
    Date:
    Summer 2002
  • Aetomylaeus sp.
    (Smooth-tail Eagle Ray partial crushing plate)
    This is a partial ray plate



    The left view is the side that did the crushing, the right is the back side of the plate

    Formation:
  • Calvert
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Chesapeake Bay Area, VA
    Size:
  • ~ 1.5 x 2" (38 x 51mm)
    Date: September, 2010 TRIP
  • Aetobatis sp.
    (Bonnet Ray partial crushing plates)

    Another Ray in the Myliobatidae family commonly found at the cliffs is the Bonnet Rays.
    Imaged here are upper Bonnet Ray plate fragments. They are easy to identify as the plate elements are "V" shaped. Lower plate fragments are more difficult to identify as the fragments look closely like Myliobatis sp.


    Formation:
  • Calvert, Plum Point member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Randle Cliffs, Calvert Co., MD
  • Myliobatis sp.
    (Eagle Ray Dental Plate fragments)
    These are probably fragments of Eagle Ray dental plates.


    Formation:
  • Calvert, Plum Point member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Randle Cliffs, Calvert Co., MD
    Size:
  • ~ 1" (25mm)
  • ? sp.
    (Ray dermal scute)

    Rays have body armor (scutes) under their skin on certain places of their bodies.

    The tops of them have what looks like an enamel scale sticking out, while the undersides look like rock fragments. Since the undersides look just like rock fragments, they can be difficult to spot.
    This is the top view of a small one. Notice the scale like structure of the scute.

    Formation:
  • Calvert, Plum Point member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y
    Location:
  • Randle Cliffs, Calvert Co., MD
    Size:
  • 3/4" (19mm)
  • ? sp.
    (Ray tail spine)
    These are fragments of ray tail spines.

    Formation:
  • Calvert, Plum Point member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y
    Location:
  • Randle Cliffs, Calvert Co., MD
    Size:
  • usually < 1" (25mm)

  • Bony Fish

    ?Acipenser sp.
    Sturgeon
    Sturgeon dermal plate fragment
    Identification based on Purdy et al (2001, p.161).
    I believe this is a tiny fragment of a Sturgeon scute.
    For an image of a better scute fragment, look at the scute on the Lee Creek collection page.

    Formation:
  • Calvert, Plum Point member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Randle Cliffs, Calvert Co., MD
    Size: ~ 1/2" (13mm)
  • Megalops cf M. atlanticus
    Tarpon

    Go to the Tarpon Fossil Gallery page for more info about Fossil Tarpon and Identification
    Click to view the fossils as found
    These are seven associated vertebra and a fragment of skull from a Tarpon.
    The fourth vertebra was left in matrix for verification of the Calvert Zone.

    Formation: Calvert: Zone 14
    Age: Early - Middle Miocene ~ 18-15 m.y.
    Location: Chesapeake Bay Area
    Size: Each vert is ~ 1.5" in diameter (38mm)
    Date: November, 2009 TRIP

    Reptiles


    Crocodilia order
    (Crocodiles)

    Thecachampsa antiqua (Leidy, 1852)
    Crocodile tooth

    Identification based on Myrick (2001, p.222)
    According to Myrick (2001, p.222), since there is a large variation in tooth shape in Thecachampsa dentitions, and there are no important morphological differences between the skulls of crocodiles found in the Chesapeake Group and other tertiary deposits, all the crocodiles should be assigned to T. antiqua.


    This is one of the best fossil crocodile teeth I've ever seen. Even though it has no root, It's beautiful. Looks like it came out of the mouth yesterday, even though it is Miocene in age.

    Click on the pic to see the trip it was found on.


    Formation:
  • Calvert
    Age:
  • Middle Miocene ~ 15-12 m.y.
    Location:
  • Chesapeake Bay Area
    Size:
  • 2 1/2" slant height (54mm)
    Date:
  • April, 2007 TRIP


  • This is another nice crocodile tooth. Although it has a large crack in it, it is large and has nice coloration.

    Click on the pic to see the trip it was found on.


    Formation:
  • Calvert
    Age:
  • Middle Miocene ~ 15-12 m.y.
    Location:
  • Chesapeake Bay Area
    Size:
  • 2 height (51mm)
    Date:
  • November, 2013 TRIP
  • fossil crocodile tooth - miocene - maryland - calvert formation


    This is a really nice looking fossil crocodile tooth. However, it's only about an inch in size.

    Click on the pic to see the trip it was found on.

    Click here to see the picture as it was found


    Formation:
  • Calvert
    Age:
  • Middle Miocene ~ 15-12 m.y.
    Location:
  • Chesapeake Bay Area
    Size:
  • 1" height (25mm)
    Date:
  • September 2012 TRIP


  • This croc tooth is damaged. However, the damage reveals the internal struture of a crocodile tooth.


    Formation:
  • Calvert
    Age:
  • Middle Miocene ~ 15-12 m.y.
    Location:
  • Chesapeake Bay Area
    Size:
  • ~ 1" (25mm) Date: September, 2010 TRIP


  • This is a very worn Croc tooth. The key to identifying it as a croc tooth is the conical cavity at the bottom of the tooth. A crocodile cavity is different than one from a sperm whale tooth.


    Formation:
  • Calvert
    Age:
  • Middle Miocene ~ 15-12 m.y.
    Location:
  • Chesapeake Bay Area
    Size:
  • ~ 1" (25mm) Date: September, 2010 TRIP


  • This is the most worn Croc tooth I have ever seen, however, it is a very nice reddish brown color.


    Formation:
  • Choptank
    Age:
  • Middle Miocene ~ 15-12 m.y.
    Location:
  • Matoaka cottages, Calvert Co., MD
    Size:
  • ~ 7/8" (23mm)

  • Testudine order
    (Turtles)

    Turtle Vertebra
    After being misidentified for over a year, I finally realized this is most of a turtle vertebrae. The first pic is the side that connects to the neural scute, and the last is a side view, where the rib would attach. I think determining its Genus would be nearly impossible due to the poor condition of the vert.

    Formation:
  • Calvert, Plum Point member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Randle Cliffs, Calvert Co., MD
    Size: ~1 1/4" by 6/8" (31mm by 18mm)

  • Cheloniidae family
    (Hard-shelled Seaturtles)

    Syllomus aegyptiacus
    Carapace of a Hard-shelled Sea Turtle
    Click on the pic for more info/ better pics!
    I found most of a turtle carapace (top of a turtle shell). It is in kinda bad shape, due to the waves beating it up.. It was found in a chunk of cliffies along the water.


    Click on the image for up to date pics, and more information.

    Formation:
  • Choptank (zone will be determined shortly)
    Age:
  • Middle Miocene ~ 15-12 m.y.
    Location:
  • Near Kenwood Beach, Calvert Co., MD


  • Marine Mammals

    Pinnipedia order
    (Seals, Walrus, etc..)

    Phocidae sp.
    Seal Cervical Vertebra (C-3 to C-7?)

    Identification based on Timmerman (1997, p.18).
    seal fossil from calvert cliffs
    This looks almost identical to a seals' 3 through 7th cervical (neck) vertebrae.

    It was found near the base of a cliff partially in clay, with the spinous process shattered, lying around it. We did our best to piece it together.

    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y
    Location:
  • Randle Cliffs, Calvert Co., MD
    Size:
  • ~3 7/8" by 2" wide (98 by 51 mm)

  • Cetacea order
    (Whales)


    Odontocete sub-order
    Toothed Whales
    (Including Dolphins type animals)

    Squalodon sp. tooth
    A Squalodon, or"Shark-toothed whale" was a type of primitive toothed whale belonging to the extinct Squalodonotidea family and S. tiedemani. I don't know which species this is. For more information about Squalodons, please take a look at the Squalodon Gallery.

    This is probably a worn incisor (tip of tooth, and bottom of root are missing). Squalodon teeth are very hard to find, and much rarer than shark teeth, as whales do not constantly loose their teeth like sharks do. Also, these are less common than the more modern looking Mysteceti, or baleen whales, found here.


    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y
    Location:
  • Plum Point, Calvert Co., MD
    Size:
  • ~ 2 1/4" (57mm)

  • Kentriodontidae and Eurhinodelphidae family
    (extinct Dolphin like animals, etc..)

    There were perhaps a dozen or so genus of "dolphins" in this area in the Miocene. Some of the common genus includes the extinct Kentriodon and Eurhinodelphis genus. For more information about the Eurhinodelphis genus, look at the additional Eurhinodelphis information in the Gallery section.

    Odontocete associated bones
    from some kind of small Dolphin like animal

    This is a clay block with associated "dolphin" bones in it.
    associated fossil dolphin bones from the Calvert Cliffs - Miocene
    These were found in a clay block in the surf. A few bones were sticking out. It contains a really nice atlas vertebra, some rib fragments, and parts of the brain case of the skull.
    It is a really interesting fossil find.

    Go to the November, 2013 TRIP trip to see it as found, and being prepped.

    Formation: Choptank
    Age: Early - Middle Miocene ~ 18-15 m.y.
    Location: Chesapeake Bay Area
    Date: November, 2013 TRIP
    "Dolphin" Teeth
    Dolphin teeth are much rarer than shark teeth, as dolphins do not continuously loose their teeth. Also, it is more difficult to spot dolphin teeth, as they tend to roll around in the waves. They are usually found by sifting in the pebble areas.
    This is a larger than normal dolphin like tooth.

    Click on the pic to see the trip it was found on

    Formation:
  • Calvert
    Age:
  • Early - Middle Miocene ~ 18-15 m.y
    Location:
  • Chesapeake Bay Area
    Size:
  • ~ 1 1/2" (38mm)
  • This is a larger than normal dolphin like tooth.

    Click on the pic to see the trip it was found on

    Formation:
  • Calvert
    Age:
  • Early - Middle Miocene ~ 18-15 m.y
    Location:
  • Chesapeake Bay Area
    Size:
  • ~ 1 5/8" (31mm) Date: September, 2010 TRIP
  • These are some kind of primitive dolphin type teeth. There were numerous species, but I have no clue how to further identify them.

    With that said, the teeth are most likely from the Kentriodon and/or the Eurhinodelphis genus. Both genus have small teeth such as these.

    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y
    Location:
  • Randle Cliffs, Calvert Co., MD
    Size:
  • ~ 5/8" (16mm)
  • Dolphin like animal Periotic ear bone
    Ear bones are difficult to spot, as they look like pebbles. It takes a trained eye to spot these.
    These are "dolphin" inner ear bones. They are often mistaken for rocks, especially if they are worn such as the ones in the image.
    The inner ear bones (the tympanic bulla and periotic) are made from very dense bone, and therefore, often fossilize.
    A dolphin bulla can be seen on the Lee Creek collection page.

    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Willows, Calvert Co., MD
    Size:
  • ~ 1/2 to 1" (51mm)
  • "Dolphin" Cervical Vertebra
    Identification based on Timmerman (1997, p.18).
    This is a dolphin cervical vertebra. They are easily identifiable due to the placement of the processes (mostly missing here), and their thinness compared to other vertebrae.

    If you notice, this particular vertebrae has the ephesis fused, which means it is from an adult. Since it is from an adult, and is relatively small, it probably came from a smaller dolphin like genus such as the Kentriodon genus.

    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Willows, Calvert Co., MD
    Size:
  • ~ 2" (51mm)
  • These are two additional dolphin cervical vertebrae.
    I'm not sure what genus these verts are from.

    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Plum Pt., Calvert Co., MD
    Size:
  • ~ larger one is 3.5" (87mm) including the remaining processes
    Date: Summer, 2002
  • Complete "Dolphin" Upper Thoracic Vertebra
    Identification based on Timmerman (1997).
    This is by far the best thoracic vertebra I have ever come across.
    It was found in a chunk of clay in the water. It took a while to prep. I also left this fragile vert in matrix to help preserve it and to display it.
    Click on the pic for images of finding it, and preparation.

    Formation:
  • Calvert, Plum Point Member, Zone 10
    Age:
  • Middle Miocene ~ 16-15 m.y.
    Location:
  • Randle Cliffs, Calvert Co., MD
    Date: May 2003
  • Dolphin Thoracic Vertebra
    Kentriodon sp. vertebra
    This appears to be a thoracic vertebra of a small species of Kentriodon Dolphin. The processes are obviously missing.

    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y
    Location:
  • Willows, Calvert Co., MD
    Size:
  • ~1 1/8" (28.5mm)
  • Dolphin Misc. Vertebra
    Identification based on Timmerman (1997).
    These three vertebrae are most likely from Dolphin like animals
    The middle one is the typical condition they are in when found on the beaches.

    The far right one is a caudal (tail) vertebra.

    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • middle one is from Randle Cliffs, the others are from Plum Pt., Calvert Co., MD
  • Epiphyses from a Dolphin Vertebra
    "Cookies"

    Identification based on Timmerman (1997, p.4).
    Epiphysis is a part of a bone (usually the end) that ossifies separately from the bone. The epiphyses also attached to the bone at a later date. So, in a juvenile, the epiphyses are usually not yet attached. When a juvenile dolphin or whale dies, the epiphyses often separate from the bone before fossilization. The detached epiphyses from the vertebrae of juveniles resemble cookies.
    The far right vertebra in the "misc vertebra" picture has its epiphysis missing.

    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Randle Cliffs, Calvert Co., MD
    Size:
  • ~1 3/8" (34mm) diameter, 1/2" (13mm) thick
  • Dolphin Rib... most of one
    Identification based on Timmerman (1997).
    This is most of a dolphin rib. It appears to be a rib from the rear of rib cage, or a floating rib. It was dug out of a chunk of freshly fallen zone 10, however, before I found it, I smashed the hammer through the center of the rib, thus loosing about 1/2" of the middle of the rib. It is also curved more than this flat image shows.

    Notice the small bite marks all over the rib, they are hard to see in this image.

    Formation:
  • Calvert, Plum Point Member, Zone 10
    Age:
  • Middle Miocene ~ 16-15 m.y.
    Location:
  • Randle Cliffs, Calvert Co., MD

  • Mysteceti sub-order
    (Baleen Whales)

    Balaenopteroidea Family
    Early Baleen Whales

    Baleen Whales are filter feeders that have no teeth. Instead they scoop up large amounts of water containing krill and small fish. The baleen filters out the food from the water. Today, Baleen whales are the largest animals on earth. These include the Blue Whales, Gray Whales, and Humpback Whales, amung many others.

    The early Baleen Whales of the Chesapeake group were smaller than todays Baleen whales.
    Fossil Baleen Whale Jaw / mandible from the Calvert Cliffs - Miocene
    This is a broken baleen whale jaw found in the Choptank Formation. It is the lower left mandible. It was found shattered near the surf in a couple chunks of cliff that fell.
    The ends are not present. Also, the posterior end, the end that attaches to the skull, is missing. This end has the defining characteristics to identify it to a genus level. As a result, this fossil cannot be identified past the family level.

    Formation: Choptank
    Age: Early - Middle Miocene ~ 18-15 m.y.
    Location: Chesapeake Bay Area
    Size: 28" (710 mm). The whole fossil would have been around 40".
    Date: November, 2013 TRIP
    Cetotherium
    Fragment of a squamosal cranial element from a Cetotherium?
    (ENGLISH TRANSLATION: Back piece of the skull from an early baleen whale?)
    Click on the pic for more info!
    According to some very qualified people at an MGS meeting, this is probably a fragment of the squamosal (rear piece of the skull) from possibly a baleen whale (Mysticeti).

    It was found while snorkeling for fossils.

    Click on the image for more pictures.

    Formation:
  • Choptank
    Age:
  • Middle Miocene ~ 15-12 m.y.
    Location:
  • Matoaka Cottages, Calvert Co., MD
    Size:
  • ~ 7" x 7" x 4.5"


  • Misc Bone Fragments
    Small bone fragments, such as rib pieces, and chunks of cartilage are abundant at the cliffs.

    These are most likely fragments from dolphins, whales, and seals

    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Randle Cliffs, Calvert Co., MD


  • Other Stuff

    Predation evidence
    The white line on the side view is a small gash, probably a scrape mark by a small shark tooth. Also, the puncture marks in the top view may also be from small shark teeth, as there are smaller punctures on the other side, which may be from the opposite row of teeth.
    Also, look at the dolphin rib in the marine mammals section, it has small bite marks all over it.

    Formation:
  • Calvert, Plum Point Member
    Age:
  • Early - Middle Miocene ~ 18-15 m.y.
    Location:
  • Randle Cliffs, Calvert Co., MD
    Size: ~1.5" (31mm)