For so-called “living fossils”, the maxim “if it ain’t broken, don’t fix it” would seem to apply. Surviving relatively unchanged for tens, even hundreds of millions of years, these very special plants and animals have each managed to find a successful ecological niche and have stuck with it.
Horsetails are an unusual group of plants that reproduce via spores instead of seeds. Now limited to a single genus, Horsetails were once the dominant plant of the prehistoric world, first appearing in the Devonian period approximately 375 million years ago. Today’s Horsetails, oddly enough, are poisonous to horses.
(image via: Arcadia Street)
Kings of the Carboniferous period when giant dragonflies and six-foot long millipedes thrived in the planet’s supersaturated oxygen atmosphere, ancient relatives of Horsetails called Calamites soared up to 90 feet high as they competed for sunlight with the world’s earliest trees.
Monkey Puzzle Tree
Monkey Puzzle or Araucaria trees are an ancient species of evergreen conifer that is today only found in some parts of Argentina and Chile. The trees have oddly scaled branches – the scales are actually leaves – and have distinctive bark likened by some to reptilian skin. The trees are tough and hardy, and can grow to heights of 130 feet and diameters of up to 6 feet.
(image via: M. Alan Kazlev)
Samples of Monkey Puzzle trees were first brought to Great Britain in the early 19th century and by the 1850s the trees were being grown at botanical gardens. As for the unusual name, it’s said that a visitor to Pencarrow Garden in Cornwall, upon observing the odd tree, suggested that “It would puzzle a monkey to climb that”. Monkey Puzzle trees are often used by artists to ‘flesh out” prehistoric scenes, like the one above from the BBC TV series “Walking With Dinosaurs” that features an Allosaurus on the prowl.
Crinoids (Sea Lillies)
If ancient oceans can be compared to modern forests, then Crinoids were the trees. These ancient progenitors to echinoderms like sea urchins and starfish built their stem-like structures from minerals extracted from seawater. The tiny calcified discs that made up Crinoid stems are extremely common in fossil-bearing shale and limestone dating back to the Ordovician period, a time roughly 475 million years ago when the only life on Earth – plant or animal – lived in the sea.
Today’s Sea Lillies and Feather Stars, though much less common in number and range, haven’t changed all that much from their Crinoid ancestors and live their lives pretty much the same way: filter-feeding tiny organisms from passing currents. You’d think that after a half-billion years Crinoids could learn something new, say, like how to walk… well guess what:
The Chambered Nautilus is the sole remaining representative of the nautiloids, a group of marine creatures that can be traced back to the Cambrian period approximately a half a billion years ago. Yes, billion.
Though they may superficially resemble cephalopods like squids and octopi (not to mention Futurama’s Dr. Zoidberg), the Nautilus’ eyes have no lenses, its 90-odd tentacles have no suckers, and it finds its prey using organs called rhinophores that can detect certain chemicals in ocean water.
Nautiloids were once rulers of the seas, sporting a bizarre range of shell designs ranging from tightly coiled to open spirals to “party hat” cones up to 13 feet long! Cthul’hu most definitely approves.
Horseshoe Crabs are not crabs at all, being related to scorpions, spiders and ticks. They may also be related to ancient giant sea scorpions, at one time the world’s largest and most feared predators… luckily that time was 420 million years ago.
(image via: Fotopedia)
Horseshoe Crabs are jawless, have 5 pairs of legs and 9 eyes. Not bizarre enough? Horseshoe Crabs have blue blood – copper, not iron, is used in their version of hemoglobin: hemocyanin.
Fossils of extinct Horseshoe Crab species have been found in rocks dating back 445 million years, to a distant era when trilobites were abundant and most animal life existed in warm, shallow seas. Indeed, it can be stated that today’s Horseshoe Crabs are the closest living relatives of trilobites.
The poster child for living fossils, Coelacanths were known strictly from the fossil record dating back almost 400 million years and were thought to have died out at the end of the Cretaceous Period along with the dinosaurs. Then in 1938, headlines were made when a trawler caught a live one off the east coast of South Africa. Since then, Coelacanths have been caught (though rarely) in other locations and live ones have been observed in their natural habitats.
(image via: MFS Updates)
Coelacanths display dark, mottled scales and their lifespan is unknown. A recent sighting of what seems to be a newborn baby Coelacanth was recorded by a Japanese research team in early 2009 and showed the fish to have a rich, indigo blue coloration set off by lighter spots.
Coelacanths are lobe-finned fish, thought to resemble those ancient fish species that evolved into the first land vertebrates over 350 million years ago. Indeed, the closest taxonomic relatives of Coelacanths are lungfishes and tetrapods (four-legged vertebrates).
Even among sharks, a group of marine creatures that has changed little over many millions of years, the Goblin Shark is an oddball. Not much is known about this denizen of the deep ocean but the few available facts are enough to rate noteworthiness: growing up to 11 feet long, the Goblin Shark sports a bizarre upper “snout” that acts as an electrical receptor to help it locate prey. It has extendable jaws lined with sharp teeth that pull any prey animals into its mouth.
Goblin Sharks are predominantly pink in color with contrasting bluish fins. The pinkness is caused by the sharks’ semi-transparent skin allowing the color of its blood to show through. Some say Goblin Sharks are the ugliest fish in the sea – considering the image above lower left, it’s hard to argue.
Tuataras are found in New Zealand and the current 2 species are the only survivors of the order Sphenodontia, which dates back roughly 200 million years. Tuataras grow to be about 30 inches long and have an unusual and unique dental arrangement: two rows of teeth in the upper jaw that overlap a single row on the lower jaw. Though true reptiles, Tuataras have certain bones in their skeletons that are shared with fish.
(image via: New Zealand 2009)
The Tuatara’s main claim to fame is its relatively well-developed parietal eye: a “third eye” on top of its head. The eye has a lens and retina (covered by scales in adults) though it is not used in conjunction with the other two eyes. Instead, it’s thought that the Tuatara’s third eye may note changes in light cycles that the creature uses to regulate its circadian rhythms. Some other reptiles, amphibians and fish have parietal eyes, though not to the extent of those possessed by the Tuatara.
The Hoatzin is in many ways more a throwback than a fossil, mainly in respect to the claws juveniles exhibit on their wings. These bizarre, quite un-birdlike claws assist the young Hoatzins in staying on tree branches. Hoatzins are rare in the fossil record with only a portion of a 50-million year old skull having been found to date. Their relationship to modern birds, even with the aid of DNA testing, is still very murky and subject to interpretation.
(images via: Berkeley U and ETSU)
Hoatzins are found in a large portion of South America’s Amazon river basin where they are not considered to be threatened. Though humans have historically eaten Hoatzin eggs from time to time, the flesh of the birds are said to taste bad. Even getting close to a Hoatzin is problematic due to a foul, manure-like odor the birds create in their digestive system and release when they feel menaced – this attribute has given the Hoatzin the informal name of “Stinkbird”.
The “Duck-billed Platypus” of Australia is a Monotreme, a mammalian genus that split off the Mammal family tree at a remote time in the past. Platypus relatives in the fossil record go back approximately 167 million years to when the dinosaurs ruled the world. Even with all that time in which to evolve, the Platypus remains primitive compared to today’s placental mammals.
(image via: Wildwatch)
An egg-layer, the Platypus secretes milk for its young but has no nipples: milk is excreted through skin pores and collects in grooves on the female’s abdomen. The creature’s superlative skill is in detecting prey though electroreception: the Platypus’ duck-like bill is designed to sense muscular contractions in its prey, chiefly worms and molluscs.
(image via: Animal Diversity Web)
The Platypus is one of a very few mammals that are venomous – a trait is shares with several tiny shrews and solenodons (shrew-like creatures). Only male Platypuses are venomous and use sharp spurs on their webbed hind feet to deliver venom to predators and/or rival platypuses. The venom is extremely painful to humans and it’s said that victims suffer from excruciating pain for days, weeks and on occasion even months!
Though their long, uneventful existence on Earth can be interpreted as proof of biological success, many of these “living fossils” have survived only because their habitats have undergone a minimum of change. Recent and future climate change will undoubtedly effect plants and animals whose basic forms and physiognomies have remained static. Can they adjust after evolving so little for so long?ï»¿