Hobbies And Interests
Mollusks
Mollusks belong to the phylum mollusca, an ancient and diverse group of largely marine animals. Well known sea mollusks include the octopus, giant squid, colossal squid, scallops, clams, mussels, slugs and snails. Complex mollusks figure among the earliest metazoans, or multicellular animals with nervous systems, organs and rigid body shapes.
The ancestors of mollusks date to Precambrian times, or longer than 543 million years ago. A cache of fossilized marine animals found by scientists in 2010 showed that complex sea life existed nearly 500 million years ago, approximately 30 million years before the previously held estimate. Mollusks appeared among these fossils.
Sea Turtles
Seven species of sea turtles exist at time of publication. Six of the seven species of these ancient marine animals appear on lists as either endangered or threatened. Sea turtles first appeared in the Earth's seas 200 million years ago, during the Triassic period. Some ancient sea turtles, such as Archelon ischyros, exhibited carnivorous, predatory behavior and measured as big as 15 feet long and 16.5 feet across.
An Archelon ischyros fossil found in the 1970s weighs over 4,500 lbs. Six modern species of sea turtles evolved between 2 and 6 million years ago, while the leatherback turtle, which faces extinction in 2011, evolved 20 million years ago.
Sundry Ancients
A number of other ancient groups of marine animals exist. Ichthyosaurs, or ancient reptiles that resembled dolphins, lived in the ancient inland seas and coastal waters of North America, as did the predatory reptiles of the plesiosaur group, which sported giant, fanged teeth and long necks, resembling folkloric sea creatures like the Loch Ness Monster. Mosasaurs resembled crocodiles though lacked legs and measured as long as 33 feet. Species found among the cache of nearly 500 million year old fossils discovered in 2010 include horseshoe crabs, sponges and annelid worms.
Arachnids
Arachnids, or arthropods (invertebrates with exoskeletons and jointed limbs) with four pairs of legs, have existed on earth for approximately 400 million years. The oldest group of arachnids belonged to scorpiones, the scorpion order, and comprised a group of ancient marine scorpions.
In 2003, scientist discovered a fossilized, silk-spinning arachnid, Aphantomartus pustulatus, about the size of a penny that bears a strong resemblance to modern spiders. This proto spider, which lived approximately 300 million years ago, belongs to an ancient group of arachnids believed to be among the first animals to live on land.