A unique Cretaceous–Paleogene lineage of piranha-jawed pycnodont fishes
A unique Cretaceous–Paleogene lineage of piranha-jawed pycnodont fishes
复制标题
食人鱼颌密齿鱼独特的白垩纪-古近纪谱系
作者：
R. Vullo;L. Cavin;Bouziane Khalloufi;M. Amaghzaz;N. Bardet;N. Jalil;E. Jourani;Fatima Khaldoune;E. Gheerbrant
已灭绝的密齿鱼目是中生代和新生代早期鱼类区系中最具特征的组成部分之一。这些鳍鱼，经历了爆炸性的形态多样化在晚白垩世，通常被认为是典型的贝壳破碎机。在这里，我们报告不寻常的切割型齿系从古近纪的摩洛哥，这是分配给一个新的属高度专业化的密齿鱼。这个独特的分类群代表了一个新的，以前未被发现的4000万年谱系（Serrasalmimidae fam.）的最后一个成员。十一月，包括另外两个新属和Polygyrodus白色，1927），其时间可以追溯到晚白垩世早期，并导致了完全的肉食性食肉形式，这在密齿兽中是独特的和意想不到的。我们的发现表明，最新的nacious-earlier古近纪pycnodonts占据更多样化的营养生态位比以前认为的，利用新的猎物类型在这个时间间隔不断变化的海洋生态系统的出现。营养专业化的进化序列的特点，这一新的组pycnodontiforms是惊人的相似，观察到serrasalmid characiforms，从种子和水果吃pacus食肉食人鱼。
The extinct group of the Pycnodontiformes is one of the most characteristic components of the Mesozoic and early Cenozoic fish faunas. These ray-finned fishes, which underwent an explosive morphological diversification during the Late Cretaceous, are generally regarded as typical shell-crushers. Here we report unusual cutting-type dentitions from the Paleogene of Morocco which are assigned to a new genus of highly specialized pycnodont fish. This peculiar taxon represents the last member of a new, previously undetected 40-million-year lineage (Serrasalmimidae fam. nov., including two other new genera and Polygyrodus White, 1927) ranging back to the early Late Cretaceous and leading to exclusively carnivorous predatory forms, unique and unexpected among pycnodonts. Our discovery indicates that latest Cretaceous–earliest Paleogene pycnodonts occupied more diverse trophic niches than previously thought, taking advantage of the apparition of new prey types in the changing marine ecosystems of this time interval. The evolutionary sequence of trophic specialization characterizing this new group of pycnodontiforms is strikingly similar to that observed within serrasalmid characiforms, from seed- and fruit-eating pacus to flesh-eating piranhas.