An international research team has identified a previously unknown prehistoric animal that lived in present-day Tanzania roughly 240 million years ago during the Triassic period. Named Dinodontosaurus isiyavamanda, the new species is far more than a simple addition to the fossil record. Published on September 15 in the Journal of Vertebrate Palaeontology, the findings help scientists accurately date key fossil regions and reshape the timeline of early dinosaur evolution.
The research solves a fossil mystery lasting over 60 years. As early as 1963, a British expedition discovered abundant synapsid fossils in Tanzania. Synapsids, the ancient vertebrates related to modern mammals, once dominated terrestrial ecosystems long before dinosaurs appeared. These fossils were stored in London’s Natural History Museum for decades. While some were thoroughly analyzed, a skeleton of a plant-eating dicynodont and a fragmentary skull remained underexamined, leaving their exact species unknown.
Recent reanalysis of the specimens brought a surprising breakthrough. Researchers confirmed that the two fossil samples belonged to the genus Dinodontosaurus, which was previously only discovered in South America. Further anatomical comparison proved the Tanzanian fossils represented a brand-new species. Its name honors the Wamanda people, local residents of the fossil discovery site in Tanzania.
The discovery provides a vital geological link between Africa and South America. Scientists once matched Tanzanian fossil-bearing rocks with Middle Triassic deposits in South Africa, assuming they formed in the same period. However, the coexistence of Dinodontosaurus in Tanzania and South America builds a new correlation standard for rock sequences. Advanced radiometric dating shows South American fossil layers are about 10 million years younger than their South African counterparts.
This conclusion rewrites previous academic judgments. Fossils in Tanzania, once regarded as evidence of the earliest dinosaurs, are no longer considered the oldest dinosaur remains. Researchers are now required to re-examine the time and geographical background of early dinosaur evolution.
Hady George, lead author from the University of Bristol, stressed the significance of the finding. “This is the first confirmed Dinodontosaurus fossil record outside South America. It calibrates the age of Tanzanian and South American fossil rocks and refines the timeline of dinosaur origins.” Co-author Nigel Larkin recalled that he had judged the skeleton as an undescribed new species in his 1994 postgraduate thesis. Thanks to modern technologies like micro-CT scanning and international cooperation, the team finally completed the in-depth research.
The study also highlights the great value of museum collections. Many fossil specimens stored for decades still have the potential to update human understanding of prehistoric life. Researchers will continue to study the unanalyzed body bones of Tanzanian Dinodontosaurus and explore the biomechanics and ecological characteristics of Triassic dicynodonts, aiming to explain how multiple large herbivores coexisted stably before dinosaur dominance.
28. What can we learn about Dinodontosaurus isiyavamanda?
A. It was first discovered in South America.
B. It is a newly identified dicynodont species.
C. It lived alongside the earliest dinosaurs.
D. It was named after the discovery site’s landscape.
29. Why does the discovery change scientists’ previous judgment?
A. It proves Tanzanian fossil rocks are younger than thought.
B. It updates the research method of radiometric dating.
C. It shows South African fossils have no research value.
D. It confirms dinosaurs originated in South America.
30. What is implied about museum-stored fossils?
A. They are less valuable than newly discovered ones.
B. They were fully studied soon after being collected.
C. They can bring new scientific breakthroughs.
D. Their preservation condition needs immediate improvement.
31. What is the best title for the text?
A. A 60-year-old Fossil Mystery Finally Solved
B. New Species Rewrites Dinosaur Evolution Timeline
C. Advanced Technologies Boost Paleontology Research
D. Links Between African and South American Fossils答案与详细解析
28. B 细节理解题
解析：根据文章第三段，该化石属于双齿兽类（dicynodonts），且是科学界从未发现的新物种。A项错误，该属化石此前仅在南美发现，新物种发现于坦桑尼亚；C项错误，该物种早于恐龙繁盛期；D项错误，物种名源自当地瓦曼达族群，而非地貌。
29. A 推理判断题
解析：文章第五、六段指出，结合迪诺龙化石分布和放射性测年技术，坦桑尼亚曾被认为是最古老恐龙证据的化石层，实际比此前判定的年代更年轻，推翻了以往结论。B、C、D三项均与原文信息不符。
30. C 推理判断题
解析：最后一段点明，本次研究印证了封存数十年的博物馆化石仍具备极高科研价值，能够刷新人类对史前生命的认知、带来新的科学突破。A、B项与原文相悖，D项原文未提及。
31. B 主旨大意题
解析：全文围绕新史前物种的发现展开，核心意义是修正了恐龙早期演化的时间线与地理认知。A、C、D三项均为文章局部细节，无法概括全文主旨。
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