Evolution of Dentary Diastema in Iguanodontian Dinosaurs |
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作者姓名: | Katsuhiro KUBOTA Yoshitsugu KOBAYASHI |
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作者单位: | Kanna Dinosaur Center, Gunma 3701602, Japan;Hokkaido University Museum, Hokkaido University, Hokkaido 0600810, Japan |
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摘 要: | The dentary diastema of iguanodontians has been considered to be related to its unique jaw mechanism for herbivorous adaptation. The dentary and diastema lengths of iguanodontians were measured and compared to elucidate the evolution of iguanodontian diastema. A gap in ratios between most non-hadrosaurid iguanodontians and hadrosaurids was observed, suggesting that all non-hadrosaurid iguanodontians, expect for Ouranosaurus nigeriensis and Protohadros byrdi, lack a diastema or have a short diastema, although some other taxa have been considered to have a long diastema in previous studies. In non-hadrosaurid iguanodontians, some large-sized forms, such as Iguanodon bernissartensis, Shuangmiaosaurus gilmorei, and possibly Eolambia caroljonesa, had a short diastema through ontogeny, whereas Ouranosaurus nigeriensis and Protohadros byrdi developed a long diastema convergently. The development of a long diastema of hadrosaurine hadrosaurids may be different from that of lambeosaurine hadrosaurids. Some hadrosaurines (Edmontosaurus annectens, Edmontosaurus regalis, and Saurolophus angustirostris) may have developed a long diastema in the subadult stage and showed little elongation of dentary diastema through ontogeny. Lambeosaurines (Corythosaurus casuarius and Lambeosaurus lambei) tend to have a short diastema in the embryonic and subadult stages, and an elongated diastema from the subadult to adult stages.
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关 键 词: | Cretaceous dentary diastema dinosaur iguanodontian ontogeny |
收稿时间: | 9/7/2007 12:00:00 AM |
修稿时间: | 5/5/2008 12:00:00 AM |
Evolution of Dentary Diastema in Iguanodontian Dinosaurs |
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Authors: | Katsuhiro KUBOTA Yoshitsugu KOBAYASHI |
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Institution: | 1. Kanna Dinosaur Center, Gunma 3701602, Japan;2. Hokkaido University Museum, Hokkaido University, Hokkaido 0600810, Japan |
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Abstract: | The dentary diastema of iguanodontians has been considered to be related to its unique jaw mechanism for herbivorous adaptation. The dentary and diastema lengths of iguanodontians were measured and compared to elucidate the evolution of iguanodontian diastema. A gap in ratios between most non‐hadrosaurid iguanodontians and hadrosaurids was observed, suggesting that all non‐hadrosaurid iguanodontians, expect for Ouranosaurus nigeriensis and Protohadros byrdi, lack a diastema or have a short diastema, although some other taxa have been considered to have a long diastema in previous studies. In non‐hadrosaurid iguanodontians, some large‐sized forms, such as Iguanodon bernissartensis, Shuangmiaosaurus gilmorei, and possibly Eolambia caroljonesa, had a short diastema through ontogeny, whereas Ouranosaurus nigeriensis and Protohadros byrdi developed a long diastema convergently. The development of a long diastema of hadrosaurine hadrosaurids may be different from that of lambeosaurine hadrosaurids. Some hadrosaurunes (Edmontosaurus annectens, Edmontosaurus regalis, and Saurolophus angustirostris) may have developed a long diastema in the subadult stage and showed little elongation of dentary diastema through ontogeny. Lambeosaurines (Corythosaurus casuarius and Lambeosaurus lambei) tend to have a short diastema in the embryonic and subadult stages, and an elongated diastema from the subadult to adult stages. |
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Keywords: | Cretaceous dentary diastema dinosaur iguanodontian ontogeny |
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