#archosaurs

Salutations to the Saltwater Crocodile

The saltwater crocodile (Crocodylus porosus), also known as the estuarine crocodile, is a species of crocodile found in the coasts and islands of southeast Asia, and the northern coast of Australia. As their name implies, saltwater crocodiles reside in saltwater and brackish environments, including coastal mangroves, river deltas, swamps, and floodplains. Adult C. porosus may also occasionally be seen out at sea, as they are proficient swimmers capable of traversing between islands and coastlines.

Saltwater crocodiles are the largest species of crocodile, and indeed of all reptiles. Males are significantly larger than females; adult males can range anywhere from 3.5 to 5 m (11 ft 6 in – 16 ft 5 in) in length and weighs between 200 to 1,100 kg (440 to 2,430 lb), while females range only a measly 2.7 to 3.4 m (8 ft 10 in to 11 ft 2 in) in total length and weigh 76 to 200 kg (168 to 440 lb). Both sexes are olive, with a lighter underbelly and darker spots along the back.

C. porosus's breeding season occurs in the wet season, beginning in September or October. After a female selects her mate, the pair dig a nest, and the female lays a clutch of 40-60 eggs. The pair then guard the nest together until the eggs hatch about 90 days later. The sex of the hatchlings is dependent on the average temperature at which the egg was incubated; between 28–33° C (82-91° F) the hatchlings are predominantly male, while incubation temperatures on either side of that range produce predominantly female hatchlings. The female continues to care for the hatchlings, guarding them by carrying them in her mouth, until they disperse at about 8 months old. Young reach sexual maturity at 10 years old, and individuals may live for as long as 70 years.

Saltwater crocodiles are active mainly at night, and spend most of the day basking on banks or partially submerged logs. As adults, they are opportunistic predators with a wide variety of prey, including mud crabs, turtles, snakes, juvenile crocodiles, birds, buffalo, kangaroos, tigers, wild boar, monkeys, and humans. As juveniles, they target smaller prey such as insects, amphibians, crustaceans and small fish. They hunt via ambush, dragging their prey back into the water for easier consumption. Adults have no natural predators, but juveniles are frequently predated upon by monitor lizards, larger fish like barramundi, wild boar, storks, eagles, and pythons.

Conservation status: C. porosus is considered Least Concern by the IUCN. They are often hunted for their skin, meat, and eggs, although international trade of saltwater crocodile parts is prohibited. They are also hunted for their perceived threat to nearby human populations. Habitat loss and human encroachment is also a major threat for estuarine crocodiles.

Photos

Fabian Roudra Baroi

Jafet Potenzo Lopes

Dinosaur Tianyuraptor ostromi, of Late Cretaceous, China!

Tianyuraptor ostromi is part of the Microraptoria clade, a clade of dromaeosaurs known for long feathers on both their legs and arms giving them “four wings”. However, Tianyuraptor had unusually short arms for a microraptorian, paired with unusually long lower hindlimbs. It was also larger than all other known microraptorines. Tianyuraptor was likely not doing any gliding, but was instead adapted as a ground-based pursuit predator.

Found in the Yixian Formation of Late Cretaceous China, Tianyuraptor ostromi would have lived alongside a plethora of other theropods, including other microraptorians like Sinornithosaurus and Zhongjianosaurus, compsognathids like Sinosauropteryx, a variety of avialans like Zhongornis, Yixianosaurus, Shanweiniao, Sapeornis, Longicrusavis, Hongshanornis, Iteravis, Dalingheornis, Archaeorhynchus, and Confuciusornis, oviraptorosaurs like Similicaudipteryx, therizinosaurs like Beipiaosaurus, and tyrannosauroids like Dilong. Tianyuraptor could have also met ankylosaurs like Liaoningosaurus, ceratopsians like Psittacosaurus lujiatunensis, and hadrosaurs like Jinzhousaurus. Pterosaurs also lived here, including ctenochasmatids like Cathayopterus and Elanodactylus, istiodactylids like Luchibang, and other pterodactyloids like Ningchengopterus.

First, of course, there's birds- all birds are classified as dinosaurs. Some do LOOK more like what we'd expect of a dinosaur than others. I am particularly fond of:

The Ostrich- the biggest bird, flightless and with much of its body lacking feathers.

The Cassowary- big, notoriously vicious flightless bird with a nasty kick.

The Shoebill- Just look at it.

The Hoatzin- notable for retaining small claws on its wings to climb with when young.

The Golden Eagle- a formidable bird well-known for attacking large mammals.

But, if you want something that looks more like the popular image of a dinosaur-ie a big scaly reptile-you can't beat crocodilians. People often refer to Komodo dragons as living dinosaurs, but they're both less closely-related than crocodilians (which share a pretty close common ancestor with dinosaurs and are the only other living members of the archosaurs, or ruling reptiles), but frankly crocodilians are more impressive animals.

The apex of course is the Saltwater Crocodile.

Though big American Alligators can get up there.

And of course I would be remiss if I did not mention the more upright land-walking Cuban crocodiles (land crocodiles have developed periodically over time).