Euoplocephalus tutus

Statistics

Meaning of name: "protected well-armored head"; genus name from Greek eu ("true", "well"), hoplon ("armor"), and kephale ("head"), after the armor on its head; Latin tutus ("protected") refers to the armor as a whole

Length: 5.3 meters (17.4 feet)

Height: 1.5 meters (4.9 feet)

Mass: 2 tonnes (2.2 US tons)

Lifespan: 16 years

History

Euoplocephalus is a genus of ankylosaurian dinosaur. The genus was established in 1910 by Lawrence Lambe to rename "Stereocephalus" tutus, named by him in 1902, since the name Stereocephalus had already been given to an insect. The original specimen consists of the parts of the skull and a half-ring; many specimens were referred to it in later years but were since reassigned to other genera like Anodontosaurus, Dyoplosaurus, Platypelta, and Scolosaurus.

Euoplocephalus was originally considered to be a stegosaur, as all armored dinosaurs were thought to be. It was reassigned to the Ankylosauridae in 1917 and has not been moved since. The genus has been synonymized with Palaeoscincus and Ankylosaurus in the past, although it is now seen as separate.

Description

Specimens referred to Euoplocephalus were the most complete ankylosaurs known for decades, so its life appearance is that of the archetypal ankylosaur. It has a medium-sized head, a comparatively low rump, and a stiffened tail. Its armor consists of four horns, two neck half-rings, a tail club, keeled oval plates, and conical spikes, famously including two large spikes behind the shoulders.

Both males and females are leather brown with chocolate-brown backs. Males' armor is cream-colored with orange tips on their head and neck armor, while females' armor is uniformly grayish-brown.

Habitat

Euoplocephalus is only reliably known from the Dinosaur Park Formation of Alberta, Canada, dating to the Campanian stage of the Late Cretaceous period. The formation represented a floodplain with rivers.

On Proxissima A, Euoplocephalus lives in the temperate broadleaf forests of the continent of Shuwa, specifically in the regions of Buganda, Maghrib, Slowenien, Watunis, Feilubin, Lamkawa, Yetnam, and Aotearoa.

Behavior

Euoplocephalus is crepuscular, mostly active in the morning and evening. It is a solitary animal, living alone or in groups of up to three, typical consisting of both parents and their single young, or a single female and her young from the past two years. Each individual or group has a home range of about 40 hectares (99 acres), which they defend by issuing low-frequency vocalizations.

Reproduction

Mating season lasts during the boreal autumn. Males and females come together only during this time of year, with males approaching females closely to determine their ability to mate, although the female can choose to reject his advances. Courtship is highly visual and depends on a male's showiness -- with each male having a different pattern and color of head armor, there is much competition. If two males come across the same female, they may challenge each other with tail club striking matches. If a male is unsuccessful, he may choose to live the rest of his life as a solitary bachelor.

Females lay a single egg that hatches after six months. Both parents -- if they are still together -- take turns raising the hatchling, or scuteling. The hatchling can walk and stand without hours and are fed and protected until they are about eight months old, when they learn to fend for themselves. Males leave their parents' care at one year old to start their own lives. Females can breed at one and a half years old and lay eggs at two, while males start breeding at age three.

Diet

Euoplocephalus is a herbivore. It is a non-selective browser that feeds on lichens, grasses, stems, and leaves, supplemented with insects and minerals. It mainly seeks out food items with its enhanced sense of smell. They feed in the morning and afternoon, resting in the noon and night.

Predation and Competition

Euoplocephalus competes with stegosaurs, ceratopsians, and ornithopods for food resources. It is also preyed upon by abelisaurids, piatnitzkysaurids, and metriacanthosaurids, which it deters with its armor and tail club.