Prehistoric Wild: Life in the Mesozoic

Champion of the Waters (216 MYA)

Qulonggongba Formation, China, 216 Million Years Ago

Clouds of diverse shapes and sizes float across the sky. Light from the sun emerges from one of these puffs of white. The shining glows reveal what will one day be the mountainous expanse of the Himalayas.

    However, here in the Late Triassic, it's a whole different world from what it is today. During this time, India has yet to merge with Asia, instead being positioned further south in the supercontinent of Pangea. It won't be for nearly 160 million years until the subcontinent collides with southern China, forming the mountain ranges we're familiar with.

    For now, this area is not a part of the land, but rather the sea. Instead of rocky highlands, there is an expanse of shallow water. Here, the level of liquid azure ranges anywhere from 100 to 1,000 feet deep. What is seen of land is a series of jagged stones constantly impacted by roaring waves. This part of the area is all but inhibited.

    To see what lives here, one must dive beneath the glimmering waves. Under here, the soft light shining from above reveals a blue world. Sitting at the bottom is an endless field of sand. Much of it is still, but small particles of it occasionally burst out of it in response to the current. Mixed in are stones of varying shapes and sizes. Some are small and pebble-like, mostly buried in the sand around them. Others are massive, towering above the sand around them.

    It is on the surface of these rocks, where streams of light dance across, that much of this area's most common forms of life rest upon. Everywhere from the top of these stones to the cracked crevices are batches of algae. They cling to stones, coating them in patches of brown among all the black and gray forms. Others float around in particles, some being too small to be seen by the human eye.

    These particles are the main food sources of another form of life present here. All over the sand and even on the larger stones are countless forms of bivalves. Clams, oysters, scallops, file shells, and hatchet shells litter the ocean floor in droves. They hardly do much, outside of constantly opening and closing their shells to suck in the loose algae and other small particles.

They too are food, however, but to a more active form of life. Swimming above them are various shelled cephalopods, ancestors of squid and octopus. Most familiar of them is the Cosmonautilus, an ancestor of the modern chambered nautilus. Its appearance is remarkably similar to its extant counterpart, everything from the coiled, banded shell and the fleshy tentacles that dangle out from it. White primarily covers its body with reddish-brown bands.

These don't directly pose a danger to the living clams, but rather eat up deceased ones and any other dead organisms it can scavenge off of. However, the clams that are still alive have to contend with a different relative of the Cosmonautilus. It's not around today but has been long forgotten by time.

They are Halorites, a type of ammonite. These too are cephalopods with a spiral shell on their back. However, in comparison to the Cosmonautilus, they appear proportionately larger. These ammonites too have tentacles that tuck in and out as a fleshy tube propels them through the water. Unlike the Cosmonautilus, it has much more earthy colors of dark brown and bands of mossy green.

Utilizing their tentacles, they easily trap and bivalves they come across. Their tough beaks then make quick work of their meal by crunching it apart. Once done, the remains are spat out from their tentacles as they move on to their next meal.

These cephalopods aren't the only active predators here. Ancient sharks litter the waters in great abundance. They appear similar to their modern relatives but have some differences in morphology. A second dorsal fin is present between the front one and the fins of their tails. Each of these top fins has a barb-like structure in front of them. Smaller horn-like structures stick out from above their eyes as well. Their smooth skin is counter-shaded with dark gray on their top half and a solid white on their underside.