Tillyardembi Fossils of the world’s first plant pollinators, called Tillyardembiids, were discovered recently in which country?

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Correct — C, Russia. The find was published on 1 March 2023 by A. V. Khramov and T. Foraponova of the Borissiak Palaeontological Institute of the Russian Academy of Sciences in Moscow, with P. Węgierek of the University of Silesia in Katowice, in Biology Letters 19: 20220523, under a title that answers the question outright: 'The earliest pollen-loaded insects from the Lower Permian of Russia'. The fossils come from the Chekarda locality on the left bank of the Sylva River, about 800 metres north-west of the village of Chekarda in the Perm region of the Cis-Urals, in the Koshelevka Formation — beds assigned to the Irenian substage of the Kungurian stage of the Early Permian, whose boundaries are dated to roughly 283–273 million years ago, which is where the widely reported figure of 'about 280 million years old' comes from. The insects are tillyardembiids (Cnemidolestida: Tillyardembiidae), a small family of Permian polyneopterans that resemble stoneflies in their forewing venation; at Chekarda they are represented almost entirely by the genus Tillyardembia, erected by G. Zalessky in 1937, and they make up about five per cent of every insect specimen collected there. The team checked 425 Tillyardembia specimens and found six — 1.4 per cent — carrying pollen: four with clusters on the head, thorax, legs and abdomen, one with a pollen mass partly extruded from the hindgut, and one previously reported specimen that re-examination showed was carrying its pollen on the outside after all. Two tests separate a pollen load from a meal. The grains sit near the lateral margins of the meso- and metathorax rather than along the mid-line where the gut runs, and they are fully intact rather than chewed or part-digested. Twenty-seven microscope slides were prepared from five specimens and 45 grains proved intact enough to identify, yielding three pollen genera — Cladaitina, Luberisaccites (assignable to Cordaitina in the broad sense) and Striatites. Cladaitina and Luberisaccites were previously extracted from the Pechorostrobus and Cladostrobus pollen organs of Rufloriaceae, an Angaran family of cordaitanthalean gymnosperms: seed plants of a world with no flowers in it. The selectivity is what carries the argument. Those pollen types are rare at Chekarda — Luberisaccites 5 per cent and Cladaitina 2.2 per cent of the site's pollen spectrum, with Striatites absent from it altogether — while the abundant wind-blown types, Protohaploxypinus at 17.6 per cent and Vittatina at 24.3 per cent, are the ones the tillyardembiids are not carrying. Pollen stuck to the outside of an insect is direct evidence of a visit to a plant's reproductive organs, and this is the earliest such evidence known, predating the previous oldest record from the Middle Jurassic by about 120 million years. One honest caveat the stem glosses over: the authors say it is impossible to establish that tillyardembiids actually pollinated anything — they may simply have robbed those plants of pollen, as many modern flower visitors do — only that a trophic specialisation of this kind could be an evolutionary precursor of pollination mutualism.

Why the other options are wrong — (a) Greece contributes nothing to this story. Its palaeontological reputation rests on Cenozoic vertebrate beds — the late Miocene mammal faunas of Pikermi in Attica and of Samos are the classic examples — which are younger than these fossils by something on the order of 270 million years, and belong to an age of grasslands and flowering plants rather than of cordaites. Greece has no Palaeozoic insect Konservat-Lagerstätte of the kind that could preserve a soft-bodied insect together with the pollen grains still adhering to its thorax.  (b) The reflex answer on an Indian paper, and it is not baseless — India's Gondwana sequences hold world-class Permian plant fossils, above all the Glossopteris flora, along with the coal that formed from them. But those beds are famous for plants, not for insects preserved with their pollen loads, and this discovery is tied to a named Russian locality in the Cis-Urals. It is worth knowing what India's genuine insect-fossil claim to fame actually is, because it is a different era altogether: Cambay amber from the lignite mines of Gujarat, about 54 million years old and therefore early Eocene, which has yielded a rich insect fauna including biting midges and fungus gnats. That is roughly 230 million years younger than Chekarda, and it comes from a world that already had flowering plants and bees.  (d) The most sophisticated wrong answer, because China really has produced a stream of spectacular fossil-insect discoveries in recent decades. But its celebrated insect-bearing deposits are Mesozoic — the Jehol biota of the Early Cretaceous Yixian Formation in Liaoning is the best known — and the paper's own review of earlier work makes the point exactly: before 2023 the ancient pollen-carrying insects on record came mostly from Cretaceous ambers, with a handful of Jurassic kalligrammatid lacewings and Early Cretaceous brachyceran flies carrying sparse grains near their mouthparts. The Palaeozoic has no ambers with macroscopic biological inclusions at all, and until this paper the only Palaeozoic arthropod known with pollen stuck to its outside was a fragmentary Upper Carboniferous Arthropleura, a millipede relative, with a few grains at the base of a leg. That is exactly why the record is held by a Permian compression fossil from Russia rather than an amber from East Asia.

Concept: Insect pollination is usually told as a story that begins with flowers, but the fossil record keeps pushing the relationship back into the age of gymnosperms — conifers, cycads, cordaites and their relatives, which reproduce by cones and naked seeds rather than flowers. The strongest possible evidence for such a relationship is pollen physically attached to an insect's body, because it shows the animal was on the plant's reproductive organs rather than merely living nearby. That evidence is rare, and rarest of all in the Palaeozoic. An insect trapped in resin keeps its pollen, but amber with large biological inclusions does not exist before the Mesozoic; an insect that falls into water before burial usually has its pollen washed off. So Palaeozoic evidence had until 2023 been indirect: cones and mouthparts that look adapted for insect visits, and pollen or spores found inside insect guts rather than on their surfaces, which shows only that the animal ate pollen, not that it carried any. Compression fossils that keep the external load anyway come only from exceptional sites — Konservat-Lagerstätten, deposits whose unusual chemistry preserves soft tissue and fine surface detail such as the rows of hairs on a tergite that pollen can lodge in. Chekarda is one of those sites, and it is why the record fell where it did.

State PCS 2023 Q53 — Science & Technology PYQ with Answer

State PCS 2023 Q53 — Science & Technology PYQ with Answer