Monkeydactyl

Context:

The new pterosaur fossil was discovered in the Tiaojishan Formation of Liaoning, China, thought to be 160 million years old, has been named Kunpengopterus antipollicatus, also dubbed “Monkeydactyl”.

Relevance:

Prelims, GS-I: Geography (Geomorphology)

Dimensions of the Article:

1. About Pterosaurs
2. About the Monkeydactyl Fossil (Kunpengopterus antipollicatus)
3. Tiaojishan Formation
4. Opposability of the Thumb
5. Back to basics: Jurassic Period

About Pterosaurs

• The pterosaur species were reptiles, close cousins of dinosaurs and the first animals after insects to evolve powered flight.
• They evolved into various species, while some were as large as an F-16 fighter jet, others were as small as paper airplanes.
• They flourished during all periods (Triassic, Jurassic, and Cretaceous) of the Mesozoic Era (252.2 million to 66 million years ago).

About the Monkeydactyl Fossil (Kunpengopterus antipollicatus)

• “Antipollicatus” in ancient Greek means “opposite thumbs”, and it was attached to the name because the researchers’ findings could be the first discovery of a pterosaur with an opposed thumb. It could likely be the earliest-known instance of the limb.
• It is far older than the one identified in 2019. Paleontologists had identified that species as a pterosaur that lived over 77 million years ago in what is Western Canada today.
• Named Cryodrakon boreas, it was believed to be one of the largest flying animals, which “flew over the heads of dinosaurs”, with a wingspan of over 10 metres.

Monkeydactyl and Opposability of the Thumb:

• The research team scanned the fossil of K. antipollicatus using micro-computed tomography (micro-CT), a technique making use of X-ray to image an object.
• By studying its forelimb morphology and musculature, they suggest that K. antipollicatus could have used its hand for grasping, which is likely an adaptation for arboreal life (living in trees).
• The grasping hands of primates developed as a result of their life in the trees — an opposable thumb made it easier for the common ancestor of all primates to cling on to tree branches.

Tiaojishan Formation

• Geographically, the Tiaojishan Formation is widely distributed in western Liaoning Province and the neighboring northern Hebei Province (China).
• This formation is lithologically composed of intermediate lava and pyroclastic rocks, interlayered with basic volcanic rocks and sedimentary deposits.
• It contains abundant and well-preserved fossil plants, including leaves, seeds and fruits, permineralized rhizomes and wood.

Opposability of the Thumb

• Opposability of the thumb is defined as being able to “simultaneously flex, abduct and medially rotate the thumb” in a way that one is able to bring the tip of the thumb to touch the tips of the other fingers.
• Along with humans, some ancient monkeys and apes also had opposable thumbs.
• Humans, however, have a relatively longer and distally placed thumb, and larger thumb muscles.
• This means that humans’ tip-to-tip precision grip when holding smaller objects is superior to non-human primates. This is the reason that humans are able to hold a pen, unscrew an earring stopper, or put a thread through a needle hole.

Back to basics: Jurassic Period

Spans from 200 million to 145 million years ago, and features three major epochs: Early Jurassic, Middle Jurassic, and Late Jurassic.

Early Jurassic

• Spans from 200 million to 175 million years ago.
• The climate was much more humid than the Triassic, and as a result, the world was very tropical.
• In the oceans, plesiosaurs, ichthyosaurs and ammonites dominated the seas.
• On land, dinosaurs and other reptiles dominated the land.
• The first true crocodiles evolved, pushing the large amphibians to near extinction.
• The reptiles rose to rule the world.
• Meanwhile, the first true mammals evolved, but never exceeded the height of a shrew.

Middle Jurassic

Spans from 175 million to 163 million years ago.

• During this epoch, dinosaurs flourished.
• Many other predators rose as well, such as Allosaurus.
• Conifer forests made up a large portion of the world’s forests.
• In the oceans, plesiosaurs and ichthyosaurs were flourishing.
• This epoch was the peak of the reptiles.

Late Jurassic

• Spans from 163 million to 145 million years ago.
• The Late Jurassic featured a massive extinction of sauropods and ichthyosaurs due to the separation of Pangaea into Laurasia and Gondwana in an extinction known as the Jurassic-Cretaceous extinction.
• The increase in sea-levels opened up the Atlantic seaway which would continue to get larger over time.

The divided world would give an opportunity for the diversification of new dinosaurs.

-Source: The Hindu