Jensen Bjarke, Lauridsen Henrik
Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam UMC, The Netherlands.
Comparative Medicine Lab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
J Anat. 2025 Jun;246(6):1034-1041. doi: 10.1111/joa.14198. Epub 2024 Dec 20.
The evolutionary conservation of the building plan of the heart suggests this organ is under substantial form-function constraints. Its form varies to such a degree, however, that it questions whether we understand the form-function relations of the heart. A previously published image of the heart of the sunfish (Mola mola, Tetraodontiformes) indicates the presence of an exceptionally simple topology of the chambers. Here, we describe the gross morphology of the sunfish heart (N = 7) because, we assess, this expands the known spectrum of cardiac form that is compatible with function. The usual teleost piscine compartments were present, guarded by valved junctions: sinus venosus, atrium, ventricle, and bulbus arteriosus. Especially, the ventricle was much displaced ventrally and the atrium was dorso-ventrally elongate. The ventricular central cavity exhibited a simple 90-degree curve, or a-quarter circle, and opened into an almost vertical bulbus arteriosus. Overall, the normal piscine S-topology of the cardiac chambers (when seen from the left) appeared distorted to a simpler J-shape. When compared to other fish, including a tetraodontiform boxfish, these highly unusual characters appeared to have evolved recently. The distantly related spotted tinselfish (Xenolepidichthys dalgleishi) resembles sunfish in shape, its heart is almost J-shaped, but the ventricle was sac-like and typically piscine. Surprisingly, the ventricular wall had a comparatively high proportion of compact myocardium, approximately 34%. The relative mass of the sunfish heart was typically piscine, approximately 0.08% of body mass. In conclusion, the sunfish heart may be the least curved cardiac structure described for any fully formed vertebrate.
心脏构建蓝图的进化保守性表明该器官受到实质的形态-功能限制。然而，其形态变化程度之大，让人质疑我们是否理解心脏的形态-功能关系。此前发表的翻车鱼（翻车鲀，鲀形目）心脏图像显示其腔室拓扑结构异常简单。在此，我们描述了翻车鱼心脏的大体形态（N = 7），因为我们评估这扩展了已知的与功能兼容的心脏形态谱。常见的硬骨鱼类腔室都存在，由有瓣膜的连接处保护：静脉窦、心房、心室和动脉球。特别是，心室明显向腹侧移位，心房在背腹方向拉长。心室中央腔呈现出简单的90度弯曲，即四分之一圆，并通向几乎垂直的动脉球。总体而言，心脏腔室正常的硬骨鱼类S形拓扑结构（从左侧看）似乎扭曲成了更简单的J形。与其他鱼类（包括一种鲀形目箱鲀）相比，这些非常不寻常的特征似乎是最近才进化出来的。亲缘关系较远的斑点锡鳞鱼（Xenolepidichthys dalgleishi）外形与翻车鱼相似，其心脏几乎呈J形，但心室呈囊状且典型的硬骨鱼类特征。令人惊讶的是，心室壁致密心肌的比例相对较高，约为34%。翻车鱼心脏的相对质量典型的硬骨鱼类特征，约为体重的0.08%。总之，翻车鱼心脏可能是已描述的所有完全成型脊椎动物中弯曲程度最小的心脏结构。
