PDF(Pubmed)
Abstract：
BACKGROUND: The deep (> 200 m) ocean floor is often considered to be a refugium of biodiversity; many benthic marine animals appear to share ancient common ancestry with nearshore and terrestrial relatives. Whether this pattern holds for vertebrates is obscured by a poor understanding of the evolutionary history of the oldest marine vertebrate clades. Hagfishes are jawless vertebrates that are either the living sister to all vertebrates or form a clade with lampreys, the only other surviving jawless fishes.
RESULTS: We use the hagfish fossil record and molecular data for all recognized genera to construct a novel hypothesis for hagfish relationships and diversification. We find that crown hagfishes persisted through three mass extinctions after appearing in the Permian ~ 275 Ma, making them one of the oldest living vertebrate lineages. In contrast to most other deep marine vertebrates, we consistently infer a deep origin of continental slope occupation by hagfishes that dates to the Paleozoic. Yet, we show that hagfishes have experienced marked body size diversification over the last hundred million years, contrasting with a view of this clade as morphologically stagnant.
CONCLUSIONS: Our results establish hagfishes as ancient members of demersal continental slope faunas and suggest a prolonged accumulation of deep sea jawless vertebrate biodiversity.
RESULTS: We use the hagfish fossil record and molecular data for all recognized genera to construct a novel hypothesis for hagfish relationships and diversification. We find that crown hagfishes persisted through three mass extinctions after appearing in the Permian ~ 275 Ma, making them one of the oldest living vertebrate lineages. In contrast to most other deep marine vertebrates, we consistently infer a deep origin of continental slope occupation by hagfishes that dates to the Paleozoic. Yet, we show that hagfishes have experienced marked body size diversification over the last hundred million years, contrasting with a view of this clade as morphologically stagnant.
CONCLUSIONS: Our results establish hagfishes as ancient members of demersal continental slope faunas and suggest a prolonged accumulation of deep sea jawless vertebrate biodiversity.
摘要：
背景：深海（>200m）海底通常被认为是生物多样性的避难所；许多底栖海洋动物似乎与近岸和陆地亲戚共享古老的共同祖先。对最古老的海洋脊椎动物进化枝的进化史的了解不足，掩盖了这种模式是否适用于脊椎动物。Hagfishes是无颚的脊椎动物，它们要么是所有脊椎动物的活着的姐妹，要么与七莺形成进化枝，其他唯一幸存的无颚鱼.
结果：我们使用所有公认属的盲鱼化石记录和分子数据来构建针对盲鱼关系和多样化的新假设。我们发现，在二叠纪〜275Ma出现后，冠状斑鱼持续了三次大规模灭绝，使它们成为现存最古老的脊椎动物谱系之一。与大多数其他深海脊椎动物相比，我们一直推断，可追溯到古生代的斑鱼占领大陆坡的深层起源。然而，我们表明，在过去的一亿年里，斑鱼经历了显著的体型多样化，与这种进化枝的形态停滞的观点形成对比。
结论：我们的研究结果将马虎鱼确定为底栖大陆坡动物群的古老成员，并表明深海无颚脊椎动物生物多样性的长期积累。
结果：我们使用所有公认属的盲鱼化石记录和分子数据来构建针对盲鱼关系和多样化的新假设。我们发现，在二叠纪〜275Ma出现后，冠状斑鱼持续了三次大规模灭绝，使它们成为现存最古老的脊椎动物谱系之一。与大多数其他深海脊椎动物相比，我们一直推断，可追溯到古生代的斑鱼占领大陆坡的深层起源。然而，我们表明，在过去的一亿年里，斑鱼经历了显著的体型多样化，与这种进化枝的形态停滞的观点形成对比。
结论：我们的研究结果将马虎鱼确定为底栖大陆坡动物群的古老成员，并表明深海无颚脊椎动物生物多样性的长期积累。
