The platypus: ancient general electrician

[wet]

Platypuses Emerged 120 Million Years Ago
Jennifer Viegas, Discovery News
Discovery News : Discovery Channel

Oct. 22, 2007 -- Close relatives of the platypus, a semi-aquatic mammal that
is so unusual scientists at first thought it was a hoax, emerged much
earlier than previously thought, scientists announced recently.

Instead of dating to long after the great extinction event that wiped out
the dinosaurs, as researchers suspected, it is now believed that platypus
descendents, including those of their echidna relatives, go back to at least
the Early Cretaceous period, and possibly even earlier.

The Early Cretaceous is associated with the first appearance and prominence
of numerous dinosaur groups.

The key to the platypus puzzle was an ancient egg-laying mammal relative
called Teinolophos trusleri, whose fossils have been collected over the past
decade.

"It suggests that both the platypus and echidna lineages were distinct by
120 million years ago, and that the platypus, at least, has occupied its
stable niche as an electro-receptive aquatic predator ever since," explained
Timothy Rowe, who announced the finding at the Society of Vertebrate
Paleontology annual meeting in Austin, Texas.

Rowe, a vertebrate paleontologist at the University of Texas at Austin, and
his team used a high-resolution X-ray CT scanner to examine the Teinolophos
trusleri remains.

The scans revealed a large internal canal located in the animal's lower jaw.
Platypuses today still have this canal, which is involved in electrical
signal detection. Around 40,000 neurons, present in the platypus duckbill,
pick up signals that prey, such as tadpoles, shellfish and bugs, emit as
they swim. The neurons exist in thick, cable-like fibers that leave large
canals in the platypus's lower and upper jawbones.

Since no other mammal, including echidnas, can surpass the electro detection
abilities of the platypus, researchers had thought this was a relatively
new, "high-tech" skill that the animal evolved. They were very surprised to
discover that the ancient close relative of platypuses had the ability too.

A larger question is, how did such an unusual creature, with its venom, duck
bill, beaver tail and otter-like feet, emerge in the first place, and how
did it survive the devastating dino extinction event?

Kenneth Angielczyk, assistant curator of paleomammalogy at The Field Museum
in Chicago, told Discovery News that the platypus might have benefited by
the fact that it was not a top predator.

"Work that we've done so far suggests that poor competitors, i.e., weedy
species, have an advantage when disturbance strikes, perhaps because they
can do a lot of different things to survive, but don't do any of them well
enough to be strong competitors under normal circumstances," he explained.

Angielczyk, along with colleagues Steven Wang and Peter Roopnarine, also
announced their research at this week's SVP meeting.

They found that carnivore-rich, but herbivore-poor, animal communities tend
to not fare as well as communities with a lot of vegetation consumers. The
former, which dominated the planet from around 318-270 million years ago,
faded off over time.

While the platypus is not a veg-loving herbivore, it is now known that it
squeaked past the mass extinction event.

Angielczyk said, "Maybe the platypus was just in the right place at the
right time."

[naiad]

Originally Posted by wet

Since no other mammal, including echidnas, can surpass the electro detection
abilities of the platypus, researchers had thought this was a relatively
new, "high-tech" skill that the animal evolved. They were very surprised to
discover that the ancient close relative of platypuses had the ability too.

Maybe the ability is not new, but a 'throwback' to fish and amphibians which have this ability. Several groups of fishes can detect electricity, including sharks, rays and the elephant-nose, knife-fish and electric eel. Sharks and rays detect the electrical impulses of their prey with sensitive pores on their snout, perhaps similar to the platypus. The elephant-nose, knife-fish and electric eel produce an electric field of a few volts with special organs in the tail, and then detect distortions in the field with organs in the snout. This allows them to navigate in total darkness or murky water. Three unrelated species, the electric ray, electric eel and electric catfish, can also generate a high-voltage burst of electricity to kill prey or for self-defence.

[sciencemike]

Originally Posted by naiad

. . .the electric ray, electric eel and electric catfish, can also generate a high-voltage burst of electricity to kill prey or for self-defence.

Convergent Evolution at its best.

But seriously did the "electric stick" also have the "ugly stick" attached to it?

[naiad]

Originally Posted by sciencemike

But seriously did the "electric stick" also have the "ugly stick" attached to it?

Something from a movie?