Bizarrely, many species of animals, such as the carp and platypus, lost their stomachs in the evolutionary past, and new research suggests they may never evolve the organs back.
The stomach is the part of the gut where the main part of digestion takes place. Glands in this organ secrete enzymes known as pepsins, which break down proteins, and strong acids that soften food and help the enzymes work. The glands first appeared about 450 million years ago, and they represent an evolutionary innovation found exclusively in jawed creatures with backbones.
Surprisingly, the gastric glands that define the stomach are missing in a number of jawed vertebrates. In 1805, the French zoologist Georges Cuvier discovered that many teleosts, or the largest living group of fish, such as the carp family, lack stomachs. The past 200 years of research suggests that up to 27 percent, speaking conservatively, of all teleost species may lack stomachs. Primitive bony fish such as lungfish and some cartilaginous fish such as chimeras lost the organs as well…
An indigenous Australian legend has it that the first platypus was the odd offspring of a duck named Tharalkoo and a rat. In a nod to the tale, researchers have named a newly identified ancient giant platypus species Obdurodon tharalkooschild.
All that was found of the creature was a single tooth at a site in Queensland, estimated to be between 5 million and 15 million years old. The molar (above, right) shows wear that indicates that the platypus probably crushed hard-shelled prey, like turtles (above, left), also found fossilized at the site.
The platypus is an improbable mishmash of an animal: It has a furry, otterlike body, a ducklike bill and webbed feet, and a beaverlike paddle tail. Like those other animals platypuses swim well and spend much of their time in the water. Unlike otters or beavers, they lay eggs—one of only two mammals known to do so. Male platypuses also have venomous stingers on their rear feet. These animals burrow near the water’s edge and feed by digging underwater for worms, shellfish, and insects.
This is either a miniature thylacine, or a damn giant of a platypus…thylacines ranged from 40-70 lbs (20-30 kg) as adults (they were about the size of a small greyhound, but built more for stamina than speed), and platypuses are considered BIG if they reach 6 lbs (2.6 kg).
Roosevelt’s Thrilling Experiences in the Wilds of Africa Hunting Big Game. Marshall Everett, 1909.*
*No, this scene is not from Africa. It is from an account of another explorer later in the book, who went to Tasmania
Did you know that baby Platypus (Ornithorhynchus anatinus) are called “Puggles”, as are the other monotremes, the Echidnas? Also, they hatch out of small eggs laid in a nest in a burrow near a body of fresh water. The milk their mothers feed them does not come from a nipple, it just oozes from small pores in the skin.
(photo: Faye Bedford, Land Learn NSW)
(a baby platypus enjoys breakfast at a zoo in Australia)
Platypus Genome, They Look Strange on the Inside Too
(May 8, 2008)
by John Noble Wilford
If it has a bill and webbed feet like a duck, lays eggs like a bird or a reptile but also produces milk and has a coat of fur like a mammal, what could the genetics of the duck-billed platypus possibly be like? Well, just as peculiar: an amalgam of genes reflecting significant branching and transitions in evolution.
An international scientific team, which announced the first decoding of the platypus genome on Wednesday, said the findings provided “many clues to the function and evolution of all mammalian genomes,” including that of humans, and should “inspire rapid advances in other investigations of mammalian biology and evolution.”
The research is described in Thursday’s issue of the journal Nature by a group of almost 100 scientists led by Wesley C. Warren, a geneticist at Washington University School of Medicine in St. Louis. The single subject of the study was a female platypus named Glennie, a resident of Glenrock Station in New South Wales, Australia, whose DNA was collected and analyzed.
“What is unique about the platypus is that it has retained a large overlap between two very different classifications, while later mammals lost the features of reptiles,” Dr. Warren said in an interview.
In their investigation of the platypus genetic blueprint, the scientists found that its genome contains about 18,500 genes, similar to other vertebrates and about two-thirds the size of the human genome. The platypus shares 82 percent of its genes with the human, mouse, dog, opossum and chicken. Some repeated elements in the genome, the scientists noted, hold hints as to the chronology of changes in the platypus…
(read more: NY Times) (photo: Peter Arnold | BIOS)
Did you know that male Platypus (Ornithorhynchus anatinus) have venom spurs on their hind legs, located on the ankles? They use the venom in fights with other platypus over territory and females, as well as in defense. The venom is said to be extremely painful, and it has been shown to kill some animals.
Distressed Platypus, Little Flood Victim in Good Hands
by Brigid O’Connell | Sunday Herald Sun
She is small enough to fit in cupped hands, but this little platypus has endured a mammoth journey since being swept from her burrow in floods this week. The three-month-old baby was found on Tuesday off Raymond Island, in the Gippsland Lakes. Vets at Healesville Sanctuary, who are caring for the infant, believe its mother may have drowned. Weighing just 335g, the unnamed platypus is in a critical condition.