Scientists have identified the fossil of a giant bird that lived about 50 million years ago, with wingspans of up to 21 feet that would dwarf today’s largest bird, the wandering albatross.

Try this PYQ:

Q.The term “Sixth mass extinction/ sixth extinction is often mentioned in the news in the context of the discussion of

(a) Widespread monoculture practices in agriculture and large-scale commercial farming with indiscriminate use of chemicals in many parts of the world that may result in the loss of good native ecosystems.

(b) Fears of a possible collision of a meteorite with the Earth in the near future in the manner it happened 65 million years ago that caused the mass extinction of many species including those of dinosaurs.

(c) Large scale cultivation of genetically modified crops in many parts of the world and promoting their cultivation in other parts of the world which may cause the disappearance of good native crop plants and the loss of food biodiversity.

(d) Mankind’s over-exploitation/misuse of natural resources, fragmentation/loss of natural habitats, destruction of ecosystems, pollution and global climate change.

Pelagornithids

• Called Pelagornithids, the birds filled a niche much like that of today’s albatrosses and travelled widely over Earth’s oceans for at least 60 million years.
• They are known as ‘bony-toothed’ birds because of the bony projections, or struts, on their jaws that resemble sharp-pointed teeth, though they are not true teeth, like those of humans and other mammals.
• The bony protrusions were covered by a horny material, keratin, which is like our fingernails, the researchers said.
• Called pseudoteeth, the struts helped the birds snag squid and fish from the sea as they soared for perhaps weeks at a time over much of Earth’s oceans, they said.

Their extinction

• The pelagornithids came along to claim the wingspan record in the Cenozoic, after the mass extinction and lived until about 2.5 million years ago. Around that same time, teratogens, now extinct, ruled the skies, they said.
• The newly described fossil — a 50 million-year-old portion of a bird’s foot — shows that the larger Pelagornithids arose just afterlife rebounded from the mass extinction 65 million years ago, when the dinosaurs, went extinct.
• The last known pelagornithid is from 2.5 million years ago, a time of changing climate as Earth cooled, and the ice ages began.

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