eyes, to be called Vetulicola and Chuandianella, watch us carefully, while another form with a short head shield, bulbous eyes, and large spines on its tail region scuttles away, crab-like. Amid these strange arthropods are the more familiar trilobites, but, unlike in later Cambrian deposits, they are fewer in number and diversity than their more esoteric cousins. Most are the familiar redlichiacean trilobites with numerous segments, forms that Darwin and his contemporaries considered the oldest animals on Earth and forms that are so striking because of their many segments. The trilobites here are heavily armored compared to the many other thinner carapaced arthropods among them, and these other poorly skeletonized forms will not commonly fossilize. At all localities save this one and a few others, which because of special circumstances will preserve soft parts, only the trilobites will be found, giving the false impression that they were the most common members of the fauna. Here we see that they are only a minor part of the fauna.

While most of this arthropodan assemblage is fairly small in size, we see bigger animals too. There are several arthropod forms that look like sea scorpions and some that have flattened oval-shaped bodies such as the enigmatic Saperion. All of these are somewhat intermediate in size, and now we search for the top carnivore of this ecosystem—it too is an arthropod—and we do not have long to wait. Swimming lazily through the water, some meters above the teeming bottom, we see a meter-long Anomalocaris, famous from the Burgess and here as well, showing its antiquity. It settles downward onto the bottom, its large paddlelike tail slowing as it lands with its many walking legs taking up the shock. With large claws slashing, it begins to feed on the many smaller, fleeing arthropods. The Anomalocaris takes note of another not as big but still substantial invertebrate on the bottom, a heavily armored lobopod, also an arthropod but one that is very rare today. This strange animal looks like a cross between an annelid worm and an arthropod and seems to be related to the still-living onycophorans of our world. The phosphate plates on the lobopods provide some protection but soon it too is killed, and the Anomalocaris centers itself over the body and begins feeding with its peculiar, circularly plated mouth.

It is time to go. As we head back toward the seashore we see one more animal. It is not an arthropod, but it does have a segmented side.



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