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Fossilladyhttps://fossillady.wordpress.comThis is where I combine my photography and writing to share my fascination with fossils, beach stones, seashells and corals.

Manuiceras sp and Cleoniceras sp Ammonite Fossil Identification and Interesting Facts

August 12, 2010 by Fossillady

Ammonite Fossil

Manuicera sp. lived in the ancient seas when the dinosaurs walked the earth. In general, the ammonite’s abundance peaked during the Cretaceous Period between 145 to 66 million-years-ago. But according to the fossil records, their incredible long history began as early as 440 mya during the Silurian Period.

This Manuicera sp ammonite fossil was unearthed from a dried up riverbed in the state of Arkansas; they have also been unearthed in the state of Texas. Both of these U.S. states lie within the limestone Goodland Formation where many other Cretaceous fossils have been discovered. Originally, I mistakenly identified the fossil as, Dufrenoy justinae, but that was when I was newer to the field with a less discerning eye and research skills. So there you go.

A variety of ammonite forms, from Ernst Haeckel‘s 1904 Kunstformen der Natur (Art Forms of Nature)

The amazing illustration above shows how ammonites vary greatly in the ornamentation (surface relief) of their shells. Some may be smooth and relatively featureless, except for growth lines. In others, various patterns of spiral ridges and ribs or even spines are shown.

Numerous ammonite fossils have been unearthed boasting a worldwide distribution which indicates the theory of continental drift. Due to their abundance of an estimated 10,000 species, scientists use them as date markers for other fossils along the same rock layers.

Ammonites grew from a few inches in diameter to the size of truck tires.

Manuiceras Ammonite Drawing

Manuiceras CLASSIFICATION

Phylum: Mollusk (soft body of invertebrate animal encased in shell)
Class: Cephalopod (means prominent head and tentacles, i.e. octopus, squid, cuttlefish, nautilus)
Order: Ammonitida (characterized by thick ribbed and patterned shells)
Family: Acanthoceratidae (known for their thick, ribbed shells, which were common during the Cretaceous period).
Genus: Manuiceras

Cleoniceras. Ammonite Fossil

Cleoniceras sp ammonite fossil is approximately 110 million years old from the early Cretacous Period unearthed in Mahajanga Province of Madagascar, Africa. It is characterized by spiraled, high-whorled, tightly coiled shells with distinct wavey ribs. These marine cephalopods are often found polished, revealing iridescent internal chambers filled with calcite or aragonite.

For additional information about these incredible marine animals, see my other article Amazing Ammonites .

Check out my two fiction books blended with prehistory insights and imaginative storytelling that entertain as they educate. Geared toward young exlporers interested in early life and fossils, or young readers who simply like a good story; ages 11-15+. Also available, a coloring/activity book featuring scenes from the books along with many of the plants and animals that lived during the amazing Devonian Time Period; fossil photos and descriptions included. Available on Amazon.com

Interesting Facts About Trilobites

August 12, 2010 by Fossillady

Calymene, celebra Trilobite Fossil

This Calymene, celebra trilobite was a scavenger finding food on the ocean floor where it could easily burrow underneath the sand to hide from predators. Many of their fossils are often found rolled up in a defensive position. They were able to bend tightly due to their chiton exoskeletons fitted with overlapping sections. Think of roly-poly bugs, or pillbugs. Calymene celebra possessed smaller eyes than many other trilobite species.

Trilobites have the distinction of possessing a segmented body, multiple jointed limbs and an armored outer shell, placing them in the category of “arthropods” related to insects and crustaceans. Trilobite means three lobes in Greek, from “tri” and “lobos”, named for their three major lengthwise body sections.

Most trilobites grew to only about 3 inches (7.6 cm) long, while a few species reached almost 3 feet (1 meter) long!

Trilobites developed several different life styles; some moved over the seabed as predators or scavengers, while others were filter feeders, yet some swam along various ocean stratas feeding on plankton. Most were sluggish swimmers, while some later varieties were designed precisely for speed and swam in the mid-ocean, pelagic zones where more predators existed.

Calymene, celebra Trilobite Fossil

This little Calymene trilobite crawled on the ocean floor around 400-440 million years ago during the Silurian to Devonian time periods, living up to 10 years. A good number of their fossils are found in Michigan and other Midwest states. During the Devonian period, Michigan and other Midwest States were situated near the equator submerged under warm shallow seas, which provided a perfect, nutrient-rich environment for trilobites to thrive in large numbers. The Calymene, celebra is Wisconsin’s official state fossil.

Trilobites existed and dominated the oceans for an amazing 270-300 million years beginning from the early Cambrian period, approximately 521 million years ago, to the end of the Permian period mass extinction, approximately 250 million years ago, which wiped out over 90% of all species living on Earth at the time.

Trilobite Drawing Illustration

Calymene Trilobite Classification

Phylum: Arthropoda (Invertebrate animals with jointed legs, segmented bodies, exoskeletons made up of chiton, a tough fibrous material often mineralized with calcium carbonate)
Class: Trilobota (Means three lobes or body sections. They are one of the earliest and most successful groups of artrhopods to appear in the fossil record with an estimated 22,000 species)
Order: Phacopida (Means lens face, these trilobites lived from the late Cambrian Period to the late Devonian Time Period)
Family: Calymenidae (Distinct, rounded shape of their head shield)
Genus: Calymene (Small group of trilobites often found rolled up)
Species: celebra

Check out my fiction books featuring factual prehistory insights blended with imaginative storytelling that entertain as they educate. Perfect for young explorers ages 11-15+ or young readers who simply like a good story, available on Amazon.com. Also available, a coloring/activity book featuring scenes from both books along with many of the plants and animals that lived during the amazing Devonian Time Period; fossil photos and descriptions included.

What is a Petoskey Stone?

February 28, 1212 by Fossillady

Polished Petoskey Stone Coral Fossil (Hexagonaria, percarinata)

Simply put, a Petoskey Stone is an extinct fossilized coral. Why is it called, “Petoskey Stone”? Because they are found in abundance in and around Lake Michigan shores, particularly near the northern Michigan city of Petoskey! The name “Petoskey” is the English adaptation of an Ottawa Indian Chief Petosegay, which is said to mean “The Rising Sun”!

They are also called “lucky stones” by many because finding these ancient coral fossils, remnants of prehistoric reefs, feels like discovering a special piece of history!

How could the remains of coral, which lived in tropical warm ocean waters, possibly find its way to the cool regions of Michigan? To explain – during the prehistoric Devonian Time Period around 416 to 369 million years ago, the landscapes of North America lay nearer to the equator and when Earth’s climate was tropical with little to zero polar icecaps. Consequently, risen, warm, shallow seas covered a large portion of the North American continent, including Michigan where the Petoskey stone “Hexagonaria, percainata” coral thrived. Eventually, the coral faced mass extinction and the coral remains were buried under deep layers of sediment. Many millions of years afterwards, around 15,000 years ago, the great glaciers retreated northward forming the Great Lakes while simultaneously digging deep into those forgotten layers of earth. Ultimately this freed the coral fossils from earth trappings and the glaciers deposited them where we can now enjoy the good fortune of discovering their mysteries.

Rough unpolished Petoskey Stone Coral Fossil (Hexagonaria, percarinata)

Petoskey Stone fossils originate from mass coral colonies of Hexagonaria, percarinata. Each hexagonal corallite, visible in the stone, held a single animal possessed of many tentacles. The tentacles siphoned food particles floating by in ocean currents and fed the food to a mouth held in the center of the corallite. The tentacles were also used to sting other organism or corallites that came too close. Calcite, silica and other minerals replaced the original exoskeleton over many millions of years.

Corallites detail of Petoskey Stone Coral Fossil (Hexagonaria, percarinata) found on Lake Michigan Beach

PETOSKEY STONE CLASSIFICATION

Common Name: Petoskey Stone or Lucky Stone

Scientific Name: Hexagonaria, percarinata

Kingdom: Animalia

Phylum: Cnidardia (means to sting)

Class: Anthozoa (ie coral, sea pens, sea anemones)

Subclass: Zoantharia (true corals)

Order: Rugosa (means wrinkled wall)

Family: Hexagonaria (means six sides)

Species: percarinata

Petoskey Stone Coral (Hexagonaria, percarinata) Rendering Drawing of Living Sample