Crocodylia

Aside from dinosaurs, the only other archosaurs to make their home on the present-day Specworld are the crocodilians. These semi-sprawling, cold-blooded archosaurs first appeared in the Triassic, emerging, with dinosaurs and several other groups, from the chaos that marked the end of the Permian. Since then, crocodiles have experimented with a number of lifestyles, from terrestrial ambusher and herbivore to marine shark- or mosark-like predator, but their favourite niches have historically been those of a semi-aquatic ambush predators. Today, most crocodilians conform to this lifestyle, and are little different from their counterparts in our timeline, but others do not.

NEOSUCHIA

Despite its name (the 'new crocodiles') this clade is almost as old as the entirety of crocodiles, reaching back to the Early Jurassic. Neosuchia includes Eusuchia, the only clade of crocodiles that survives on Home-Earth, as well as the ancient but unremarkable goniopholidids.

EUSUCHIA (True crocodiles, alligators, and caimans)

Many of Spec's crocodilians are indistinguishable from their Home-Earth counterparts; Spec's bayous are home to alligators, and its Nile is patrolled by crocodiles.

GONIOPHOLIDIDAE (Cuttercrocs)

Laymen can hardly tell these crocodiles, which have stayed almost unchanged since the Early Jurassic, apart from eusuchians – except by one feature: Goniopholidids have smooth, sharp edges on their teeth which are a formidable tool for cutting meat. Consequently, they eat more terrestrial prey and less fish than their eusuchian relatives and their attacks are quite a bit more bloody. Like eusuchians, cutters ambush their prey in water.
ZIPHOSUCHIA
The ziphosuchians, extinct in our timeline since the Miocene, when the last South American sebecosuchids died out, was – and, in Spec, is – the most diverse group of terrestrial crocodiles. Ziphosuchia includes, astoundingly, both carnivorous and herbivorous forms and lives primarily on the southern continents.

In Spec, three of ziphosuchian clades have survived: the bone-cracking crunchercrocs of sub-Saharan Africa, the herbivorous hoplocrocs of Madagascar and Africa, and the ferocious, theropod-toothed baurusuchids of Madagascar.

LIBYCOSUCHIDAE (Crunchercrocs)

A crunchercrocs is a peculiar creature, a crocodile's answer to a mammalian hyeana. Never longer than 2.5 m from snout tip to tail tip, crunchers spend most of their time lying in high grass or under trees and trusting their formidable armour. When they become hungry, however, they stand up on their surprisingly long legs and head off to wherever their meanwhile proverbial sense of smell leads them. (The smaller species even sometimes climb trees to smell farther.) This food could be anywhere – different crunchercroc species roam semideserts, savannas, dry forests and rainforests –, but most often, it is the fresh remains of a priscataur kill.

With their strong, rounded snouts, weak jaw muscles, and relatively small, sharp, bladelike teeth, moloks, pantherbulls and black beasts are very well equipped to kill prey by running into it and to take bites out of it, but they are understandably bad at cleaning and eating bones. This is where the crunchercrocs come in. With their immensely strong jaws, which are lined with many small, low-crowned, conical, broad-based teeth, 20 crunchercrocs can let the remains of a grassbag carcass disappear with no trace in 3 days.

The oldest known crunchercroc is †Libycosuchus brevirostris from the middle Cretaceous of western Africa. It is only known from a skull that already shows most of the adaptations that characterize today's crunchercrocs.

HOPLOSUCHIA (Hoplocrocs, gargants, and aardcrocs)

Hoplosuchians are bizarre terrestrial herbivorous crocodilians of Africa and Madagascar. Their low, armoured body form mirrors that of their distant cousins, the long-extinct aetosaurs, as well as that of the dinosaurian ankylosaurs and vanguards. Their skulls are short, solidly built affairs with broad snouts and closely packed leaf-shaped teeth. All species have an extensive coat of spiny osteoderms protecting their dorsal and ventral surfaces.

(fig. 1) Photograph of the skull of a rhinoceros hoplocroc, Hoplosuchus armatus

Although their Palaeogene fossil record is unknown, the hoplocrocs' ancestor was probably one of the small herbivorous crocodilians (e. g. †Simosuchus) that were widely distributed in Cretaceous Gondwana. The high diversity of hoplocrocs on Madagascar, including the presence of many primitive species, suggests that the group originated on that island and later colonized the African continent by rafting or swimming.

(fig. 2) Rhinoceros hoplocroc, Hoplosuchus armatus (Madagascar)

The rhinoceros hoplocroc is a large, conspicuous herbivore that lives in open woodland and savanna. It feeds on leaves and tender shoots, digging for roots and tubers during the drier parts of the year. These creatures are solitary, using their long horn in jousts over territory and mating rights. Interestingly, the eggs are laid and buried in a simple pit dug in the ground. The adults provide no parental care and the hatchlings are left to fend for themselves. This behavior is quite unusual among crocodiles.

(fig. 3) Gargant, Gargantuis crassus (Madagascar)

The gargant (which can weigh up to 1.2 metric tons) is the largest of the hoplocrocs. The most massive animal on Madagascar, adult gargants have little need for their armour as protection. Instead, some suspect, their chain-mail of bony scutes functions rather like a girdle, keeping these herbivores' massive digestion system of from splitting their bellies open at the seams.

Adult gargants have no natural predators, but as young, they are preyed upon by the larger species of croclion and by rukhs, which swoop down upon gargant herds to seize their young.

Afrosuchus (African hoplocrocs)

The African hoplocrocs are small and not particularly diverse. These species are small, and their armour plating tends to be more extensive than that of their cousins in Madagascar.

(fig. 3) Aardcroc, Afrosuchus terrestris (Southern African plains)

The aardcroc is a meter-long herbivore of south Africa's savanas. These creatures eat a wide variety of plant material, including herbs, grass roots, and tubers, and make their homes in burrows on the banks of rivers.

In the heat of the dry season, aardcrocs enter these mud burrows and enter a period of extended aestivation, lowering their metabolisms drastically to conserve precious water. Predators like mattiraptors and archaeoplumes have been known to search for these burrows and devour their occupants.

(fig. 4) Thresher, Afrosuchus spinifer (Central African jungles)

A cryptic and poorly-studied creature of the deep jungle, the thresher is probably related to the more widespread aardcroc. The thresher's habits are unkown, but judging by its compact build and upturned snout, it probably lives like a pig, rooting through forest detritus.

BAURUSUCHIDAE (Jagators, croclions, and croctigers)

This is a group of big ambushing meat-eaters has a poorly known but presumably glorious history that reaches back into the Late Cretaceous, when several baurusuchid species stalked across the southern continents. The baurusuchids' most conspicuous features are their theropod-like skulls with serrated teeth, uuncomfortably reminiscent of a tyrannosaur.

In our timeline, baurusuchids are not found in the Cenozoic, but in Spec they spread over much of the world in the Eocene, when India had delivered them to the northern continents. By the end of the Eocene, however, baurusuchids they disappeared from the North. Only in Madagascar, the Island of Crocs, have they survived to the present day. There, however, they have radiated into a number of terrestrial predator niches including the largest predators on the island.

Baurusuchids share the body armor and toothy maw of their amphibious relatives, the Neosuchia, but posses an almost erect stance, with all four legs nearly under the body, enabling them to trot quickly over the ground in pursuit of their prey. Like other crocodilians, baurusuchids are cold-blooded, and so all species are ambush predators, relying on camouflage to sneak up on their prey, and bursting into a sprint when the prey is close enough.

The most common group of baurusuchids, the jagators (Arborosuchus), are agile little (monitor-sized) predators with a penchant for climbing. This decidedly un-croc-like lifestyle is an adaptation for hunting the jagators' principal prey, lemurs.

A jagator climbs a tree by running up the trunk, relying on its sharp claws for purchase in the manner of a treerunner or a Home-Earth cat. Once above the ground, the jagator will flatten itself against a branch and wait for a lemur to pass by. Jagators are capable of waiting for days if necessary, but as soon as its prey comes within range, the predator will spring from immobility to blurred speed. The lemur is dispatched with a quick bite to the neck, and the jagator may feast at its leisure.

Jagators are strictly solitary, and only associate with each other during a brief and violent mating season, when females boom their invitations into the forest. These 'jagator wedding bells' sound rather like the beating of steel drums, and allow males to track down their prospective brides in the confusing maze of the forest canopy.

(fig. 4) Common jagator, Arborosuchus scansorius (Madagascar)

(fig. 5) Croclion, Crocoleo hamiltoni (Madagascar)

The croclion is the largest Malagasy carnivore. The ancestors of this giant (4-meter-long) terrestrial crocodile were probably similar to South American †Baurusuchus, but the croclion has undergone some modification in its role as the primary hunter of the hoplocrocs.

Croclions' legs are quite long and are held almost straight under the body, enabling these predators to gallop frighteningly fast, even though only for short distances. Their skulls are short (for a crocodile) and deep, and also very lightweight. Croclions hide in the tall grass, waiting for a hoplocroc to amble by, at which point they spring and use their massive jaws to bite through their prey's armour.

(fig. 6) Croctiger, Suchosmilus horridus (Madagascar)

The only species of Suchosmilus is the secretive and lethal croctiger (S. horridus). Croctigers are somewhat smaller, but much heavier than their grassland cousins. Their armour plating is extensive, and their bodies are compact and muscular, while the hindlimbs are powerful, and the forelimbs tipped with five curving talons. A croctiger's head is deeper and stronger than that of a croclion, and sports a pair of fangs that protrude several centimetres below the jaw.

All of these adaptations mould the croctiger toward one purpose, hunting sauropods. massive Malagasy (and young when their parents look away). Though not as large as their cousins on the African mainland, Malagasy mokeles and gihugrongos are nonetheless extremely large herbivores. Sauropods that favour streams and the deep forest, protected by a coat of bony scutes, and armed with the strength and stamina of all warm-blooded animals, mokeles and gihugrongos make challenging prey, but the croctigers are superbly adapted for this purpose.

Unlike any other baurusuchids, croctigers are social, gathering into sibling groups to hunt. These groups wait near game trails for a mokele or juvenile gihugrongo to pass, individual croctigers fanned out on both sides of the path, where these cold-blooded stalkers can wait for days. When a mokele walks past, the croctigers all spring at once, leaping for the neck and flanks, grabbing mokele hide with their teeth and forelimb talons in a burst of activity, then allowing gravity to pull them down, making great slashing wounds. The croctigers then retreat and allow the mokele to stumble off until, weak from bloodloss and the infection carried by croctiger bites, it collapses. This final collapse may take place days after and kilometres away from the initial attack, but the croctigers track their prey unerringly with sensitive noses. When the mokele finally dies and the croctigers have gorged themselves, they slink off to their communal nest to sleep off their meal.

Croctiger sibling groups, held together by their common genes, are viciously territorial, swiftly attacking any intruder they smell within its boundaries. During mating season, however, all the males rush of the group rush off to breed with the females of other groups. They return to their own group to help raise their sisters' children, which then either replace the adults or, in times of bounty, run off to form their own groups. Loners of both sexes are not rare, but they tend to be smaller and have low fertility.

(fig. 5) Croctiger, detail of manual talons (fig. 6) Comparison of jagator and croctiger profiles

Brian Choo, Daniel Bensen, Matti Aumala and David Marjanović

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