CRAB: HEART OF A WARRIOR

Look how epic this little guy is! 

He is a crab — and if you asked him, the fiercest warrior that ever lived. While that may not be strictly true, crabs do have the heart of a warrior and will raise their claws, sometimes only millimetres into the air, to assert dominance over their world. 

Crabs are decapod crustaceans of the Phylum Arthropoda. 

In the Kwak'wala language of the Kwakwaka'wakw of the Pacific Northwest, this brave fellow is ḵ̓u'mis — both a tasty snack and familiar to the supernatural deity Tuxw'id, a female warrior spirit. Given their natural armour and clear bravery, it is a fitting role.

They inhabit all the world's oceans, sandy beaches, many of our freshwater lakes and streams. Some few prefer to live in forests.

Crabs build their shells from highly mineralized chitin — and chitin gets around. It is the main structural component of the exoskeletons of many of our crustacean and insect friends. Shrimp, crab, and lobster all use it to build their exoskeletons.

Chitin is a polysaccharide — a large molecule made of many smaller monosaccharides or simple sugars, like glucose. 

It is handy stuff, forming crystalline nanofibrils or whiskers. Chitin is actually the second most abundant polysaccharide after cellulose. It is interesting as we usually think of these molecules in the context of their sugary context but they build many other very useful things in nature — not the least of these are the hard shells or exoskeletons of our crustacean friends.

Crabs in the Fossil Record

The earliest unambiguous crab fossils date from the Early Jurassic, with the oldest being Eocarcinus from the early Pliensbachian of Britain, which likely represents a stem-group lineage, as it lacks several key morphological features that define modern crabs. 

Most Jurassic crabs are only known from dorsal — or top half of the body — carapaces, making it difficult to determine their relationships. Crabs radiated in the Late Jurassic, corresponding with an increase in reef habitats, though they would decline at the end of the Jurassic as the result of the decline of reef ecosystems. Crabs increased in diversity through the Cretaceous and represented the dominant group of decapods by the end.

We find wonderful fossil crab specimens on Vancouver Island. The first I ever collected was at Shelter Point, then again on Hornby Island, down on the Olympic Peninsula and along Vancouver Island's west coast near Nootka Sound. They are, of course, found globally and are one of the most pleasing fossils to find and aggravating to prep of all the specimens you will ever have in your collection. Bless them.

TEMPERATURE, SAND AND SEX: GREEN SEA TURTLES

What do temperature, sand and sex have in common?

Well, for the Green Sea Turtle—everything. When these cuties are still in their shells incubating, the temperature of the sand surrounding them determines their sex. 

Boy or girl? 

Warm sand produces females and cooler sand hatches out male Green Sea Turtles.

The Green Sea Turtle, Chelonia mydas, also known as the Green Turtle, Black Sea Turtle or Pacific Green Turtle is a species in the family Cheloniidae.

It is the only species in the genus Chelonia. Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic and Pacific Oceans, but it is also found in the Indian Ocean. 

The common name refers to the usually green fat found beneath its carapace, not to the colour of its carapace, which is olive to black.

This sea turtle's dorsoventrally flattened body is covered by a large, teardrop-shaped carapace; it has a pair of large, paddle-like flippers. It is usually lightly coloured, although in the eastern Pacific populations' parts of the carapace can be almost black. Unlike other members of its family, such as the hawksbill sea turtle, C. mydas is mostly herbivorous. The adults usually inhabit shallow lagoons, feeding mostly on various species of seagrasses. The turtles bite off the tips of the blades of seagrass, which keeps the grass healthy and these aquatic vegans in top shape..

Like other sea turtles, green sea turtles migrate long distances between feeding grounds and hatching beaches. Many islands worldwide are known as Turtle Island due to green sea turtles nesting on their beaches. Females crawl out on beaches, dig nests and lay eggs during the night. Later, hatchlings emerge and scramble into the water. Those that reach maturity may live to 80 years in the wild.

Researchers at the Senckenberg Research Institute in Frankfurt, Germany discovered the remains of the oldest fossilized sea turtle known to date. Remains from a new species, Desmatochelys padillai sp, including fossilized shell and bones have been found at two outcrops near Villa de Leyva, Colombia. 

The find was published in the journal PaleoBios, dates the reptile at 120 million years old – 25 million years older than any previously known specimen of this beautiful and long-lived turtle.

TEMNODONTOSAURUS CRASSIMANUS

Temnodontosaurus crassimanus

This big beastie is the ichthyosaur, Temnodontosaurus crassimanus, who graced our ancient oceans 180 million years ago. The species was originally named by Richard Owen, the first superintendent of the Natural History Museum. Owen lived at the height of the gentleman scientist and it was Owen who first coined the name dinosaur. Dean Lomax did some work with this specimen as part of his research leading up to his PhD.

The fellow you see here is the Type Specimen for the species and he lives on display in the Yorkshire Museum. As the reference specimen for the species, all hopeful specimens that may belong to this species are checked against the Type Specimen to see if they share diagnostic features.

The Yorkshire Museum was given this important ichthyosaur fossil back in 1857, albeit in bits and pieces. The first bits of fossil bones were found near Whitby on the North Yorkshire coast by workmen quarrying alum. They recognized the bones as belonging to a fossilized reptile and alerted local authorities who in turn alerted the good Master Owen.

It was quite an undertaking to recover as it was found in more than fifty pieces in massive shale blocks and the alum quarry was active at the time. Alum quarrying helped share the Yorkshire Coast as an important staple of the textile industry going back to the 16th-century. By the 1860s, alum quarrying was slowing down. The ability to manufacture synthetic alum by 1855 had shifted the industry and it died out entirely by 1871. Lucky for us, the last years of alum production gifted us this well-preserved eight-metre specimen, one of the largest ichthyosaurs ever discovered in the UK.

Paleo-coordinates: 54.5° N, 0.6° W: paleocoordinates 42.4° N, 9.3° E