Trooper

Trooper is an earth-attributed Ankylosaurus who is a member of the D-Team.

## Character design

### Personality:

Trooper is a very strong Ankylosaurus and is the Earth Champion, however he is very cranky at times. especially when he is disturbed from his beauty sleep. He is strong, clever, and is very skilled in his earth abilities. He is the older cousin of Tank and the older brother of Hannah.

### Anatomy:

As an Ankylosaurus, Trooper is the largest-known ankylosaurine dinosaur and possibly the largest ankylosaurid. his head is 64.5 centimeters (2 ft 1+1⁄2 in) long and 74.5 cm (2 ft 5+1⁄4 in) wide, and about 6.25 m (20 ft 6 in) long and had a hip height of about 1.7 m (5 ft 7 in). The smallest-known ankylosaurus is 55.5 cm (1 ft 9+3⁄4 in) long and 64.5 cm (2 ft 1+1⁄2 in) wide, and Trooper has a length of 7.56 to 9.99 m (24 ft 9+1⁄2 in to 32 ft 9+1⁄2 in) for CMN 8880, and 6.02 to 7.95 m (19 ft 9 in to 26 ft 1 in). Though the latter is the smallest specimen of *Ankylosaurus*, his skull is still larger than those of any other ankylosaurins. A few other ankylosaurs reached about 6 m (20 ft) in length. Because the vertebrae are not significantly larger than those of other ankylosaurines, Arbour and Mallon considered their upper range estimate of nearly 10 meters (33 ft) for large *Ankylosaurus* too long, and suggested a length of 8 m (26 ft) instead. Arbour and Mallon estimated a weight of 4.78 t (5.27 short tons), and tentatively estimated the weight of 7.95 t (8.76 short tons).

### Skull:

Trooper's skull differs in various details; this is thought to be the result of taphonomy (changes happening during decay and fossilization of the remains) and individual variation. The skull was low and triangular in shape, and wider than it was long; the back of the skull was broad and low. The skull had a broad beak on the premaxillae. The orbits (eye sockets) were almost round to slightly oval and did not face directly sideways because the skull tapered towards the front. The braincase was short and robust, as in other ankylosaurines. Crests above the orbits merged into the upper squamosal horns (their shape has been described as "pyramidal"), which pointed backwards to the sides from the back of the skull. The crest and horn were probably separate elements originally, as seen in the related *Pinacosaurus* and *Euoplocephalus*. Below the upper horns, jugal horns were present, which pointed backward and down. The horns may have originally been osteoderms that fused to the skull. The scale-like cranial ornamentation on the surfaces of ankylosaurs skulls is called "caputegulae", and were the result of remodeling of the skull itself. This obliterated the sutures between skull elements, which is common for adult ankylosaurs. The caputegulum pattern of the skull was variable between specimens, though some details are shared. The caputegulae are named according to their position on the skull, and those of *Ankylosaurus* include a relatively large, hexagonal (or diamond-shaped) nasal caputegulum at the front of the snout between the nostrils, which had a loreal caputegulum on each side, an anterior and posterior supraorbital caputegulum above each orbit, and a ridge of nuchal caputegulae at the back of the skull.

The snout region of *Ankylosaurus* was unique among ankylosaurs, and had undergone an "extreme" transformation compared to its relatives. The snout was arched and truncated at the front, and the nostrils were elliptical and were directed downward and outward, unlike in all other known ankylosaurids where they faced obliquely forward or upward. Additionally, the nostrils were not visible from the front because the sinuses were expanded to the sides of the premaxilla bones, to a larger extent than seen in other ankylosaurs. Large loreal caputegulae—strap-like, side osteoderms of the snout—completely roofed the enlarged opening of the nostrils, giving a bulbous appearance. The nostrils also had an intranarial septum, which separated the nasal passage from the sinus. Each side of the snout had five sinuses, four of which expanded into the maxilla bone. The nasal cavities (or chambers) of *Ankylosaurus* were elongated and separated by a septum at the midline, which divided the inside of the snout into two mirrored halves. The nasal chambers had two openings, including the choanae (internal nostrils), and the air passage was looped. The maxillae expanded to the sides, giving the impression of a bulge, which may have been due to the sinuses inside. The maxillae had a ridge that may have been the attachment site for fleshy cheeks; the presence of cheeks in ornithischians is controversial, but some nodosaurs had armor plates that covered the cheek region, which may have been embedded in the flesh.

Tooth rows in the maxillae of this specimen are about 20 centimeters (7.9 in) long. Each alveolus had a foramen (opening) near its side where a replacement tooth could be seen. Compared to other ankylosaurs, the mandible of *Ankylosaurus* was low in proportion to its length, and, when seen from the side, the tooth row was almost straight instead of arched. The mandibles are completely preserved only in the smallest specimen (AMNH 5214) and are about 41 centimeters (16 in) long. The incomplete mandible of the largest specimen (CMN 8880) is the same length. AMNH 5214 has 35 dental alveoli in the left dentary and 36 in the right, for a total of 71. The predentary bone of the tip of the mandibles has not yet been found. Like other ankylosaurs, *Ankylosaurus* had small, phylliform (leaf-shaped) teeth, which were compressed sideways. The teeth were mostly taller than they were wide, and were very small; their size in proportion to the skull meant that the jaws of *Ankylosaurus* could accommodate more teeth than other ankylosaurines. The teeth of the largest *Ankylosaurus* skull are smaller than those of the smallest skull in the absolute sense. Some teeth from behind in the tooth row curved backwards, and tooth crowns were usually flatter on one side than the other. *Ankylosaurus* teeth are diagnostic and can be distinguished from the teeth of other ankylosaurids based on their smooth sides. The denticles were large, their number ranging from six to eight on the front part of the tooth, and five to seven behind.

### Postcranial skeleton:

The structure of much of the skeleton of *Ankylosaurus*, including most of the pelvis, tail, and feet, is still unknown. It was quadrupedal, and its hind limbs were longer than its forelimbs. In the holotype specimen, the scapula (shoulder blade) measures 61.5 cm (2 ft 1⁄4 in) long and was fused with the coracoid (a rectangular bone connected to the lower end of the scapula). It also had entheses (connective tissue) for various muscle attachments. The humerus (upper arm bone) of AMNH 5214 was short, very broad and about 54 cm (1 ft 9+1⁄2 in) long. The femur (thigh bone), also from AMNH 5214, was 67 cm (2 ft 2+1⁄2 in) long and very robust. While the feet of *Ankylosaurus* are incompletely known, the hindfeet probably had three toes, as is the case in advanced ankylosaurids.

The cervical vertebrae had broad neural spines that increased in height towards the body. The front part of the neural spines had well-developed entheses, which was common among adult dinosaurs, and indicates the presence of large ligaments, which helped support the massive head. The dorsal vertebrae had centra (or bodies) that were short relative to their width, and their neural spines were short and narrow. The dorsal vertebrae were tightly spaced, which limited the downwards movement of the back. The neural spines had ossified (turned to bone) tendons, which also overlapped some of the vertebrae. The ribs of the last four back vertebrae were fused to the diapophyses and parapophyses (the structures that articulated the ribs with the vertebrae), and the ribcage was very broad in this part of the body. The caudal vertebrae had centra that were slightly amphicoelous, meaning they were concave on both sides.

### Armor:

A prominent feature of trooper was his armor, consisting of knobs and plates of bone known as osteoderms, or scutes, embedded in the skin. These have not been found in articulation, so their exact placement on the body is unknown, though inferences can be made based on related animals, and various configurations have been proposed. The osteoderms ranged from 1 centimeter (1⁄2 in) in diameter to 35.5 cm (14 in) in length, and varied in shape. The osteoderms of *Ankylosaurus* were generally thin walled and hollowed on the underside. Compared to *Euoplocephalus*, the osteoderms of *Ankylosaurus* were smoother. Many smaller osteoderms and ossicles probably occupied the space between the larger ones, as in other ankylosaurids. The osteoderms covering the body were very flat, though with a low keel at one margin. In contrast, the nodosaurid *Edmontonia* had high keels stretching from one margin to the other on the midline of its osteoderms. *Ankylosaurus* had some smaller osteoderms with a keel across the midline.

Like other ankylosaurids, trooper has cervical half-rings (armor plates on the neck), but these are known only from fragments, making their exact arrangement uncertain. Carpenter suggested that when seen from above, the plates would have been paired, creating an inverted V-shape across the neck, with the midline gap probably being filled with small ossicles (round bony scutes) to allow for movement. He believed the width of this armor belt was too wide to have fitted solely on the neck, and that it covered the base of the neck and continued onto the shoulder region. Arbour and the Canadian paleontologist Philip J. Currie disagreed with Carpenter's interpretation in 2015 and pointed out that the cervical half-ring fragments of the holotype specimen did not fit together in the way proposed by Carpenter (though this could be due to breakage). They instead suggested that the fragments represented the remains of two cervical half-rings, which formed two semi-circular plates of armor around the upper part of the neck, as in the closely related *Anodontosaurus* and *Euoplocephalus*. Arbour and Mallon elaborated on this idea, describing the shape of these half-rings as "continuous U-shaped yokes" over the upper part of the neck, and suggested that *Ankylosaurus* had six keeled osteoderms with oval bases on each half-ring.

The first osteoderms behind the second cervical half-ring would have been similar in shape to those in the first half-ring, and the osteoderms on the back probably decreased in diameter hindwards. The largest osteoderms were probably arranged in transverse and longitudinal rows across most of the body, with four or five transverse rows separated by creases in the skin. The osteoderms on the flanks would probably have had a more square outline than those on the back. There may have been four longitudinal rows of osteoderms on the flanks. Unlike some basal ankylosaurs and many nodosaurs, ankylosaurids do not appear to have had co-ossified pelvic shields above their hips. Some osteoderms without keels may have been placed above the hip region of *Ankylosaurus*, as in *Euoplocephalus*. *Ankylosaurus* may have had three or four transverse rows of circular osteoderms over the pelvic region, which were smaller than those on the rest of the body, as in *Scolosaurus*. Smaller, triangular osteoderms may have been present on the sides of the pelvis. Flattened, pointed plates resemble those on the sides of the tail of *Saichania*, and may have been distributed similarly on *Ankylosaurus*. Osteoderms with oval keels could have been placed on the upper side of the tail or the side of the limbs. Compressed, triangular osteoderms found with *Ankylosaurus* specimens may have been placed on the sides of the pelvis or the tail. Ovoid, keeled, and teardrop-shaped osteoderms are known from *Ankylosaurus*, and may have been placed on the forelimbs, like those known from *Pinacosaurus*, but it is unknown whether the hindlimbs bore osteoderms.

troopers tail club is composed of two large osteoderms, with a row of small osteoderms at the midline, and two small osteoderms at the tip; these osteoderms obscured the last tail vertebra. As only the tail club of specimen AMNH 5214 is known, the range of variation between individuals is unknown. The tail club of AMNH 5214 is 60 cm (23+1⁄2 in) long, 49 cm (19+1⁄2 in) wide, and 19 cm (7+1⁄2 in) tall. The club of the largest specimen may have been 57 cm (22+1⁄2 in) wide. The tail club of *Ankylosaurus* was semicircular when seen from above, similar to those of *Euoplocephalus* and *Scolosaurus* but unlike the pointed club osteoderms of *Anodontosaurus* or the narrow, elongated club of *Dyoplosaurus*. The last seven tail vertebrae formed the "handle" of the tail club. These vertebrae were in contact, with no cartilage between them, and were sometimes co-ossified, which made them immobile. Ossified tendons attached to the vertebrae in front of the tail club, and these features together helped strengthen it. The interlocked zygapophyses (articular processes) and neural spines of the handle vertebrae were U-shaped when seen from above, whereas those of most other ankylosaurids are V-shaped, which may be due to the handle of *Ankylosaurus* being wider. The larger width may indicate that the tail of trooper is shorter in relation to its body length than those of other ankylosaurids, or that it had the same proportions but with a smaller club.

## Abilities

### Mole Attack:

Trooper burrows underground, and a purple glow approaches his opponent along the ground before he bursts up and hits them into the air! He shares this move with his younger cousin and sister, Tank and Hannah, his long-lost cousin, Boulder, and his friends, Lola, Crystal and Lex.