My Prehistoric Saga: March 2020

Ceratosaurus:

Time: Kimmeridgian-Tithonian of the late Jurassic period: 157-145 million years ago.
Place: North America, Europe, and possibly Africa.
Length: 18-31 feet (5.4-9.5 meters).
Diet: Carnivore.

Let's talk about one of my favorite carnivorous theropods that I like to call, "the three-horned killer!"

Description:
Ceratosaurus was a medium-sized carnivorous dinosaur. It was 18-31 feet long (5.4-9.5 meters).
There are three species of Ceratosaurus from North America: C. nasicornis, C. magnicornis, and C.
dentisulcatus. There is an unnamed species of Ceratosaurus, C. sp, from Europe, and the questionable (?)C. roechlingli and (?)C. stechowi from Africa. C. nasicornis is 18-19 feet long (5.4-5.8 meters),
C. magnicornis is 20 feet long (6.2 meters), C. dentisulcatus is 23 feet long (7.1 meters), and C. sp
is 19 feet long (5.9 meters). (?)C. roechlingli and C. stechowi are too fragmentary to get a size estimate, but it could have been as large as the other species of Ceratosaurus were (of course, if it indeed is Ceratosaurus). However, Carrano et al., (2012) said that there is only one species of Ceratosaurus in North America: C. nasicornis (pg. 226).

Ceratosaurus has a large nasal horn on the top of its snout, and two large lachrymals (or lachrymal horns) in front of its eyes (Gilmore, 1920, pg. 76 and 80). It also has four fingers on its hands (Gilmore, 1920, pg. 76). This is a trait that older carnivorous dinosaurs had (Carrano and Choiniere, 2015, "Abstract"), such as Herrerasaurus (Sereno and Novas, 1992, pg. 1138). However, the fourth digit might have been useless. The second and third fingers were larger than the first and fourth ones. Its arms were also short compared to its contemporary, Allosaurus (Gilmore, 1920, pg. 103-105), but they were probably still good for grabbing prey (Carrano and Choiniere, 2015, "Abstract").

Carnivorous theropod dinosaurs had enamel in their teeth, so they must have had lips to cover and protect their teeth (Reisz and Larson, 2016, pg. 64-66) (Blake Eligh, 2016) (Mindy Weisberger, 2016) (Emanuela Grinberg, 2016) (Phys, 2016). Therefore, Ceratosaurus would have had lips covering its teeth. Interestingly, dinosaurs couldn't move its tongues (Mindy Weisberger, 2018) (ScienceDaily, 2018).

Ceratosaurus also had body armor, called dermal ossicles or osteoderms, running down its back (Madsen and Welles, 2000, pg. 32, "Dermal Ossicles") (Brian Switek, 2018, p. 2) (Joshua Lively, 2012, "Description") (Rogers et al., 2011, "Introduction," p. 1). Perhaps this might've given it some protection.

Ceratosaurus with Osteoderms (When Dinosaurs Roamed America):

Time and Place:
Ceratosaurus lived 157-145 million years ago, during the Kimmeridgian-Tithonian of the late Jurassic period. It lived in North America, Europe, and possibly Africa. However, the African species, (?)C. roechlingli and . stechowi, are considered to be a nomen dubium (Oliver W. M. Rauhut, 2011, pg. 199-202; 202-205).

In North America, Ceratosaurus fossils come from the Morrison Formation of the late Jurassic period. The Morrison Formation is made up of three major members: Tidwell, Salt Wash, and Brushy Basin (Kowallis et al., 1998, "Abstract") (Scott et al., 2001, pg. 12-14) (The University of Utah, "Morrison Formation"). According to Kowallis et al., (1998), the Tidwell Member is 155 million years old. The Brushy Basin Member is 150-148 million years old. Thus, the Morrison Formation is Kimmeridgian-Tithonian in age ("Abstract"). The Salt Wash Member is located in between the Tidwell and Brushy Basin Members (Chure and Loewen, 2020, "Age"), so it must be around 155-150 million years old. However, the Brushy Basin's maximum age seems to be 153-145 million years old (Kowallis et al., 1991, "Abstract") (Irmis et al., 2013, pg. 282). Therefore, the Salt Wash Member seems to be 155-153 million years old. In total, the Tidwell Member is 157-155 million years old, the Salt Wash Member is 155-153 million years old, and the Brushy Basin Member is 153-145 million years old. In total, the Morrison Formation is Kimmeridgian-Tithonian in age, ranging from 157-145 million years ago. Palynomorphs and calcareous microfossils prove this as well (Turner and Peterson, 1999, pg. 89-90) (Marjanovic and Laurin, 2014, pg. 2) (Dinosaur National Monument, "Rhadinosteus parvus"). Thus, Ceratosaurus lived in the Kimmeridgian-Tithonian of the Morrison Formation (Dinosaur National Monument, "Ceratosaurus").

In Europe, Ceratosaurus sp. remains come from the Lourinha Formation. The timing of the Lourinha Formation seems to be Kimmeridgian-Tithonian in age (Mateus et al., 2006, pg. 5) (Octavio Mateus, 2006, pg. 2) (Russo et al., 2017, pg. 4) (Mateus et al., 2017, "Lithostratigraphic framework," pg. 80). Therefore, it seems to be the same age as the Morrison Formation (Octavio Mateus, 2006, pg. 2).

In Africa, possible Ceratosaurus remains come from the Tendaguru Formation. The Tendaguru Formation is Kimmeridgian-Tithonian (Octavio Mateus, 2006, pg. 2) (Kristian Remes, 2006, "Abstract") (Sattler and Schwarz, 2015, "Material"). (?)Ceratosaurus remains come from the Lower Dinosaur, Middle Dinosaur, and Uppder Dinosaur Members of the Tendaguru Formation, which are both Kimmeridgian in age (Bussert et al., 2009, "Members of the Tendaguru Formation," "Lower Dinosaur Member," "Middle Dinosaur Member," and "Upper Dinosaur Member," pg. 156-157, 160-162, 164-165). However, the Ceratosaurus fossils discovered there are considered nomen dubium (questionable) (Oliver M. W. Rauhut, 2011, pg. 199-202; 202-205).

Recently, teeth discovered in the late Jurassic Tacuarembo Formation of South America have been attributed to Ceratosaurus, along with some Torvosaurus teeth (Soto et al., 2020, "Abstract").

In summary, Ceratosaurus lived during the Kimmeridgian-Tithonian of late-Jurassic North and South America, and Europe. It might have also lived in Africa, but it's not for certain.

Ceratosaurus Couple (Jurassic Fight Club):

Prey:
Since Ceratosaurus was one of the smaller carnivorous dinosaurs during its time, it doesn't seem like it would have hunted sauropods like Barosaurus and etc. Instead, it probably would have gone after smaller prey. In North America, the ornithopod Camptosaurus, the stegosaur Stegosaurus, and the ankylosaur Mymoorapelta would have been easier targets. In Africa, the stegosaur Kentrosaurus would probably have been it's prey of choice as well.

Ceratosaurus vs. Stegosaurus:

Enemies:
Ceratosaurus' enemies were numerous. They included Allosaurus, Saurophaganax, Torvosaurus, and Stokesosaurus in North America, (?)Allosaurus and Veterupristisaurus in (?)Africa, and Allosaurus, SHN.019 (a European carcharodontosaurid), and Torvosaurus in Europe.

Allosaurus vs. Ceratosaurus (Jurassic Fight Club):