The trophic habits of early birds
The trophic habits of early birds
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DOI：
10.1016/j.palaeo.2018.03.006
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发表时间：
2019-01-01
影响因子：
3
通讯作者：
O'Connor, Jingmai K.
中科院分区：
文献类型：
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作者：
O'Connor, Jingmai K.
虽然在化石记录中，揭示饮食的直接关联是极其罕见的，但丰富的下白垩纪热河拉格施塔特已经产生了数十个保存摄入物品的标本，这些标本共同揭示了有关鸟类消化道早期进化的重要信息。直接证据表明，Jeholornis和Sapeornis吃种子，像生活granivores利用胃磨，虽然只有更多的衍生Sapeornis拥有粮食储存作物。尽管它们在早白垩世的数量较少，但最直接的证据与Omithuromorpha有关，表明即使是最早的成员也存在结构和功能现代的消化道。在反鸟类中完全缺乏类似的证据，这表明这片空地的特征是原始的消化道，这可能是导致这一成功的白垩纪谱系最终灭绝的因素。在阿耶什的牙齿损失的砂囊的作用是更复杂的比在非鸟类兽脚亚目。在新鸟兽目中，基栖鸟形类中胃石的存在可能并不完全表明食草动物，尽管这种饮食似乎与这片沼泽中的牙齿完全丧失有关。正选择专门的牙齿形态持续在整个进化的Ayes和在Ornithuromorpha似乎与食鱼。虽然由最大的数字表示，没有直接的饮食偏好的指标是保存在任何confuciusornithiform或antienornithine表明这些分支利用不同的营养策略。所有孔子鸟形目动物都没有牙齿和胃石，这表明这个谱系可能是第二次转向非草食性的软食。同样地，反颚类动物没有砂囊石也暗示了它们的饮食较软，而它们的体型较小则暗示早白垩世的物种可能以无脊椎动物为食。公认的牙齿模式的多样性，包括釉质专业化观察热河antiroomithines建议有效的资源分区的无脊椎动物区系和牙齿有一个积极参与antiroomnithine喂养策略。
Although direct associations that reveal diet are extremely rare in the fossil record, the rich Lower Cretaceous Jehol Lagerstatte has produced dozens of specimens preserving ingested items, which together reveal important information regarding the early evolution of the avian alimentary canal. Direct evidence indicates Jeholornis and Sapeornis ate seeds and like living granivores utilized a gastric mill although only the more derived Sapeornis possessed a crop for food storage. Despite their smaller numbers in the Early Cretaceous, most direct evidence pertains to the Omithuromorpha, indicating a structurally and functionally modern alimentary canal was present in even the earliest members of this Glade. Similar evidence is altogether lacking in the Enantiornithes suggesting this Glade was characterized by a primitive alimentary canal, potentially factoring into the ultimate extinction of this successful Cretaceous lineage. The role of the gizzard in the loss of teeth in Ayes is more complex than in non-avian theropod lineages. As in neornithines, the presence of gastroliths in basal ornithuromorphs may not be entirely indicative of herbivory although this diet does appear to correlate with complete tooth loss in this Glade. Positive selection for specialized tooth morphologies persists throughout the evolution of Ayes and in the Ornithuromorpha appears to be linked to piscivory. Although represented by the greatest numbers, no direct indicator of diet preference is preserved in any confuciusornithiform or enantiornithine suggesting these clades utilized different nutritional strategies. The absence of teeth and gastroliths in all confuciusornithiforms suggest this lineage may have secondarily switched to a non-herbivorous, soft diet. Similarly, the absence of gizzard stones in enantiomithines also suggests a soft diet while their small body size suggests Early Cretaceous species would have fed on invertebrates. The diversity of recognized dental patterns including enamel specializations observed in Jehol enantiomithines suggests effective resource partitioning of available invertebrate faunas and that teeth had an active participation in enantiornithine feeding strategies.