July 19, 2016
TIL that the Dutch and German words for Tortoise (or Turtle) literally translate as Shield-Toad (schildpad and Schildkröte).
Of course, neither are toads, nor (it turns out) did shells arise as a protective adaptation:
For almost a century, biologists argued about how turtles got their shells—a debate almost as slow and plodding as the creatures themselves. Paleontologists mostly argued that the shells evolved from bony scales called osteoderms, which are also responsible for the armor of crocodiles, armadillos, and many dinosaurs. These scales simply expanded to fuse with the ribs and backbone, creating a solid covering. But developmental biologists disagreed. By studying modern turtle embryos, they deduced that the shell evolved from ribs, which broadened out and eventually united.
Everything changed in 2008, when Chinese researchers discovered a 220-million-year-old turtle with a shell that covered just its belly and not its back. They called it Odontochelys semitestacea—literally, the “toothed turtle in a half-shell.” It was as beautiful an intermediate fossil as they could have hoped for. And strikingly, it had no osteoderms at all. It did, however, have very broad ribs. The developmental biologists were right!
First, the lower ribs became wider and fused with each other to give half a shell—the plastron. Then, the upper ribs followed suit and merged with the spine, creating the carapace. (This means that, contrary to cartoons, you can’t pull a turtle out of its shell.) Eventually, through an intricate bit of evolutionary origami, the ribs started growing over the shoulder blades, rather than sitting below them as in you, me, and most other land-living vertebrates.
That takes care of how the shell evolved. “For me, the next question was: Why?” says Lyson. “And there are two huge reasons why not.”
How the Turtle got its shell.
September 2, 2014
An endling is an individual that is the last of its species or subspecies. Once the endling dies, the species becomes extinct.
I spotted a tweet Monday morning about Martha, the last Passenger Pigeon, she died 100 years ago but enjoyed some degree of posthumous celebrity:
It got me wondering how many other species we know (or at least think we can identify) the last member of that species.
Booming Ben, the last Heath Hen, was last spotted in 1932, he was the last member of his species for 4 years.
Long before Ben the Heath Hen was target for early conservationists, though in a turn that would be comical if it wasn’t both bad for conservation and quite racist:
Heath hens were one of the first bird species that Americans tried to save from extinction. As early as 1791, a bill “for the preservation of heath-hen and other game” was introduced in the New York State legislature. Some representatives misinterpreted the bill when it was read as an act to protect “Indians and other heathen“; although the legislation was passed, it turned out to be unenforceable.
As recently as this April the heath hen was proposed for ‘de-extinction’ by a company called Revive and Restore. The list also includes Plesitocene megafauna that have been extinct for 4,000-10,000 years. He may not be as big and flashy but I’d say Ben has a better chance.
Another Benjamin, the last Thylacine, died in Hobart Zoo in 1936. I’ve posted footage of him before, and it’s well worth watching if only to see how huge Thylacine jaws really were.
Thylacines are also a candidate for the Revive and Restore project though the Tasmanian Tiger still clocks up 40-50 unconfirmed sightings a year (the link is worth checking out for the Thylacoleo and Yowie sightings info).
Celia, the last Pyrenean Ibex was found dead in 2000, you can visit her taxidermied remains and she was briefly resurrected via cloning in 2009.
Lonesome George is one of the more famous examples, a number of attempts were made to breed him with similar sub-species but none of the eggs were viable. He died in 2012 at the age of 102, he’d been an endling for at least 40 years.
This is the quite possibly the last Rabbe’s fringe-limbed treefrog, he resides at the Atlanta Botanical Garden and has been the last known member of his species for 2 years now, though the last known female died in 2009. The species was only discovered in 2005 and the last known observation “was that of a single male heard calling (but not seen) in 2007″.
This is the last female Yangtze giant softshell turtle, she lives at Suzhou Zoo in China and is the last hope for continuing her species. She’s co-resident with one of the remaining males but after hundreds of unhatched eggs over the last 6 years it was confirmed last month that “the male is either infertile, or incapable of inseminating the female.”
The other two known members of their species live in separate lakes in Vietnam, though as the article states there have been unconfirmed sightings in the Red River in Yunan Province, and as our female certainly has no problems laying eggs artificial insemination may bring some success.
This photos contains the entire breeding population of Northern White Rhinoceros. They were formerly resident at the Dvůr Králové Zoo in the Czech Republic but were reintroduced into the wild in 2009 after the species had become extinct in the wild. One rhino remains at Dvůr Králové and two are in San Diego (a male and an infertile female). The last Northern White Rhino birth was in 2000.
In reality most endlings won’t be named, or even known. There are almost 20,000 species currently at risk of extinction.