The Prehistoric Park Animal Field Guide Volume 1

by WildExpert24

As a Prehistoric Park employee, you get the privilege to work with the likes of previously extinct animals. However, if you want to survive longer than five minutes, then you need to have knowledge of its inhabitants. From the world of Cartoon's Prehistoric Park, this Guide will give you info on behavior, diet, lifespan, and more. Welcome to the Ultimate Prehistoric Guidebook.

36. Basilemys

Basilemys

Scientific Classification

Kingdom: Animalia

Phylum: Chordata

Class: Reptilia

Order: Testudines

Suborder: Cryptodira

Family: Nanhsiungchelyidae

Genus: Basilemys, Hay 1902

Type Species: Basilemys variolosa meaning King Turtle

Described by Edward Drinker Cope, 1876.

Species:

-Basilemys gaffneyi, Sullivan et al. 2012

-Basilemys morrinensis, Mallon & Brinkman 2018

-Basilemys praeclara, Hay 1911

-Basilemys sinuosa, Riggs 1906

-Basilemys variolosa, (Cope 1876) (type)

Current Park Population: (9; all adults; 4 male, 5 female)

Park Diet: Shrubs, ferns, algae, duckweed, romaine lettuce, cantaloupe, banana, kale, mango, and strawberries.

Natural Diet: Shrubs, ferns, and aquatic plants.

Lifespan: 50 years

Habitat: swamps, floodplains, Open-Canopy forests, and Fern prairies.

Native Ecosystem: North America, Laramadia, Hell Creek Formation, Horseshoe Canyon Formation, Frenchman Formation, Oldman Formation, Dinosaur Park Formation, El Gallo Formation, Aguja Formation, Alberta, Canada, Montana, Baja California, Texas, Mexico, Late Cretaceous, Campanian-Maastrichtian, 84–66 Million Years Ago.

Breeding Season: April-July

Gestation Period: Four-Seven weeks

Eggs Laid: 30-50 eggs

Hatching Time: July-October

Danger Level: 2 out of 10.

Summary: Basilemys is the King of the Turtles during the Mesozoic and its name means "King Turtle." Basilemys is a bit of an enigma, with a carapace shape similar to aquatic turtles but the limbs and beak of a terrestrial herbivore, like a tortoise. Unlike its mostly aquatic brethren, Basilemys occupies the Hell Creek floodplains, feeding on low-growing plants. It is also a relatively large animal, matching Axestemys in size, with shell lengths averaging around a meter."

Geological Information and Discovery: Turtles were prominent members of the Upper Cretaceous and thus, their specimens found throughout North America are useful in defining biogeographic patterns. In 1924, a partial skeleton and crushed skull of Basilemys was collected by C.M. Sternberg from the Horseshoe Canyon Formation.

However, this specimen was poorly preserved and information on the skull could not be analyzed. In another part of Canada, a Basilemys specimen from the Frenchman Formation of Saskatchewan retained most of the neck and cranial fragments. This was groundbreaking because of how scarce cranial and cervical material is for Basilemys. Most of the well-preserved specimens of Basilemys are of the carapace, the hard upper shell of a turtle. Apart from the type species Basilemys variolosa, five other species have been described to date. These include B. gaffneyi, B. morrinensis, B. nobilis, B. praeclara, and B. sinuosa. In 2018, a nearly complete shell of B. morrinensis was found in the Horseshoe Canyon Formation of Alberta. Basilemys specimens have also been found from the Oldman Formation and Dinosaur Park Formation.

Other shell fragments of Basilemys have been found in the El Gallo Formation, located in Baja California. Like the Horseshoe Canyon Formation and the Frenchman Formation, the El Gallo Formation is a rich fossiliferous geological unit. The three shell fragments that were found in the El Gallo Formation represent the first record of Basilemys from the Upper Cretaceous of Mexico. Due to the ornamentation of the shell fragments, researchers were able to identify them as Basilemys. These ornamentations include shallow pits and small pyramidal elevations. Basilemys remains have also been recovered from the Aguja Formation, which stretches from Texas to Mexico. Here, shell fragments of Basilemys were found that are similar to the shell fragments found in the El Gallo Formation, also possessing the previously mentioned pits.

Description:

Basilemys sinuosa

Adults are covered with brown scales and a flat shell that is brown with light brown spots, turtle-like feet with light gray claws, a white underbelly with brown spots, a pale beak, and tortoise-like heads.

Hatchlings are tannish brown with dark brown spots over their bodies and shells.

Size: 1.5 meters in length and 100 kilograms in weight.

Skull: The proportions of Basilemys' skull are very similar to those of Adocus, Baptemys, and Zangerlia. These genera have cheek and temporal regions that are deeply emarginated. The cheek emargination is short and deep and reaches above the level of the ventral edge of the orbit. The ventro-posterior corner of Basilemys' skull lacks a posterior projection into the temporal emargination which is unlike the genus Adocus. Additionally, the temporal emargination of Basilemys projects forward and reaches the anterior edge of the cheek emargination. The deep cheek and temporal emarginations found in Basilemys are not seen in the genus Nanhsiungchelys, which is part of the same family Basilemys belongs to; Nanhsiungchelyidae. Near the center of individual bones, the skull roof of Basilemys is developed and some striations extend outwards from these central regions. In contrast, the skull roof of Nanhsiungchelys is covered by sculpture that matches the carapace. Meanwhile, in Adocus, the skull roof bones are smooth.

Resembling both Adocus and Zangerlia, Basilemys has a small external narial opening. Basilemys has a deep premaxillary border that is just below the external narial opening. In addition, the premaxillae of Basilemys are paired instead of fused to form a single element like in the Trionychia family. Similar to other trionychoids, Basilemys' orbits have large openings. At the anteroventral edge of the orbit, a groove on the external surface of the maxilla borders it. The orbit is also extensively floored by the palate which is a condition that is seen in Adocus, Baptemys, and Dermatemys.

The triturating surface of the maxilla is visible on both sides of the skull of Basilemys and has a well-developed maxillary tooth. The tooth is elongated and has a blade-like structure. It also borders a deep, circular cavity medially. A deep labial ridge is also present. The lower jaw of Basilemys is short and deep. A sharp symphyseal hook is present on the lower jaw. The coronoid process of Basilemys is low and is located near the posterior end of the jaw.

Carapace and plastron: Turtle shells are a key feature in the identification and differentiation of turtles. The shells are made up of two portions: the carapace and the plastron. The carapace is the hard dorsal shell of a turtle while the plastron is the ventral surface of the shell. Turtle shells are important because they, to varying degrees, protect them from harm. The surface texture of a Basilemys carapace consists of many small, shallow pits that are arranged in a chain-link pattern. These shallow pits are bordered by low, tetrahedral protrusions. In Nanhsiungchelys, the pits are arranged more tightly and are in transverse rows over the costals, which heavily contrasts the arrangement seen in Basilemys. The pattern of the carapace in Basilemys can be described as being nearly isotropic.

The researchers who found the carapace of B. morrinensis from the Horseshoe Canyon Formation were able to reconstruct it through drawings and distinguish the various features of the carapace. The midline of the carapace consists of vertebral scales. On B. morrinensis there are five of these scales. On the lateral sides of the vertebral scales, there are costals and pleural scales that make up another portion of the carapace. The borders of the carapace are made up of the peripherals and marginal scales. The pygal bone sits at the posterior end of the shell, and the suprapygal is right above it.

Basilemys' plastron is octagonal and elongated. The various parts that make up the plastron can be seen in the reconstion made by the researchers who recovered the B. morrinensis specimen from the Horseshoe Canyon Formation. Like the carapace, the plastron is made up of many bony elements, and the plastron can be divided into five distinct parts. At the anterior end of the plastron, the first part is the epiplastron. Following the epiplastron is the entoplastron. The next two divisions after the entoplastron are the hyoplastron and the hypoplastron. From the reconstructed images of the plastron of B. morrinensis, the hyoplastron, and hypoplastron appear to be the largest sections of the plastron. At the posterior end of the plastron, the last division is the xiphiplastron. The scales that make up the plastron include the humeral-, axillary-, pectoral-, abdominal-, femoral- and anal scales.

Histology: In a histological analysis of the shell bones of two groups of stem-trionychians, Adocidae and Nanhsiungchelyidae, it was found that the shell bones of the Nanhsiungchelyids have a diploe structure and cortical bone layers that frame the interior cancellous bone. The osteoderms of Basilemys were found to have pronounced and elaborate sculpturing patterns. The sample from the North American Basilemys showcased a highly organized "spindle-shaped" ornamentation pattern. In addition, the sculpturing pattern of Basilemys is made of irregular grooves and pits of the external bone surface which is what is typically described as the "pock-mark" surface.

Classification: Based on the specimens found from the family Nanhsiungchelyidae, researchers have been able to create cladograms based on their findings. The placement of Basilemys puts it closest to the genera Nanhsiungchelys and Zangerlia. Both are within its family, Nanhsiungchelyidae. With close examination of shell histology, along with skull and neck proportions, it was determined that, of the two, Basilemys is more closely related to Zangerlia. Based on similar characteristics, Adocus was recovered as relatively closely related to Basilemys. However, most cladograms place Adocus outside of Nanhsiungchelyidae.

Diet: Benign terrestrial, they browse on land growing plants like Shrubs, ferns, and aquatic plants along the waters edges of swamps, rivers, and ponds.

Interactions with other species: Since Basilemys live on land while Axestemsy lives in the water they often live two different worlds apart avoiding niche competition depending on their lifestyles. although Basilemys is often ignored by the large herbivores and they must avoid getting stepped on by them.

Basilemys could prey on hatchlings of dinosaurs like Ornithomimus, Thescelosaurus, Anzu, Pectindon, Acheroraptor, Trierarchuncus, birds like Brodavis, and crocodilian and choristodere hatchlings like Borealosuchus, Thoracosaurus, Champsosaurus, and Brachychampsa.

Basilemys might be potential prey to Didelphodon, often in groups they could overwhelm and kill Basilemys with their strong sharp teeth.

Hatchlings are vulnerable to Pectindon, Acheroraptor, and Juvenile Tyrannosaurus.

Predators of both hatchlings and adults Axestemys include Quetzalcoatlus, Thescelosaurus, Anzu, Borealosuchus, Thoracosaurus, Champsosaurus, and Brachychampsa whose jaws can pierce through their shells.

Extinction: Unfortunately, unlike the other reptiles and amphibians, Basilemys went extinct at the age of Dinosaurs and the extinction of its family, Nanhsiungchelyidae. This could be due to their herbivore land diet, their slow growth, and reproduction they succumb to extinction with the depletion of plants and low egg mortality rates these turtles died out with the dinosaurs and pterosaurs.

Danger Tip: They are sluggish and slow-moving when approached, when being carried it requires a team of people to lift this turtle, and other than their sharp beaks and forelimbs claws to watch out for, it's best to wash your hands after handling turtles and most animals because they could carry diseases, parasites, and viruses that can be could be spread.

Significant Events: On the third day of the first mission, a bask of Axestemys was encountered alongside floats of crocodilians and choristoderes, Brachychampsa, Borealosuchus, Thoracosaurus, Champsosaurus, Palaeobatrachus, and another turtle species, Basilemys. The Basilemys swim towards Filburt escaping a float of Brachychampsa who steps up the portal to be transported to the park. One gets left behind while Filburt manages to save her only to have his shell cracked by the Brachychampsa, he is now recovering from this event. They now reside in the Hell Creek Forest Building.

Hell Creek Forest Building Riverside habitat: This exhibit is meant to replicate the Cretaceous Riverside which is also a walk-through aviary. There is a riverbank for the turtles to bask and a large pool for the turtles to swim filled with aquatic plants and a small glass underwater viewing panel. There is a section for the land turtles for them to bask and browse on the plants growing in their enclosure, Basilemys shares its habitat with Axestemys and Brodavis.

Notable Individual:

Basil: A female Basilemys that Filburt saved from the jaws of the Brachychampsa and formed a bond with him.

Conclusion: Basilemys is an example of diverse Turtles during the Mesozoic and how they fill different niches in their environment. Basilemys are quite the slow and steady additions to Prehistoric Park.

The Field Guide might take a long time, like structuring and writing descriptions of the creatures, but also my time in college and spending time with my family. So you can suggest additional information quotes, descriptions, and natural or speculative behaviors for the prehistoric animals that I can edit and you send your suggestions either in reviews or Private Messages.

Examples: Inferring what the toons are doodling on the sketches or snarking quotes.

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