Warth Peter, Hilton Eric J, Naumann Benjamin, Olsson Lennart, Konstantinidis Peter
Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität Jena, Germany.
Department of Fisheries Science, Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, Virginia.
J Morphol. 2017 Mar;278(3):418-442. doi: 10.1002/jmor.20653. Epub 2017 Feb 7.
The head is considered the major novelty of the vertebrates and directly linked to their evolutionary success. Its form and development as well as its function, for example in feeding, is of major interest for evolutionary biologists. In this study, we describe the skeletal development of the cranium and pectoral girdle in Siberian (Acipenser baerii) and Russian sturgeon (A. gueldenstaedtii), two species that are commonly farmed in aquaculture and increasingly important in developmental studies. This study comprises the development of the neuro-, viscero- and dermatocranium and the dermal and chondral components of the pectoral girdle, from first condensation of chondrocytes in prehatchlings to the early juvenile stage and reveals a clear pattern in formation. The otic capsules, the parachordal cartilages, and the trabeculae cranii are the first centers of chondrification, at 8.4mm TL. These are followed by the mandibular, then the hyoid, and later the branchial arches. Teeth form early on the dentary, dermopalatine, and palatopterygoid, and then appear later in the buccal cavity as dorsal and ventral toothplates. With ongoing chondrification in the neurocranium a capsule around the brain and a strong rostrum are formed. Dermal ossifications start to form before closure of the dorsal neurocranial fenestrae. Perichondral ossification of cartilage bones occurs much later in ontogeny. Our results contribute data bearing on the homology of elements such as the lateral rostral canal bone that we regard homologous to the antorbital of other actinopterygians based on its sequence of formation, position and form. We further raise doubts on the homology of the posterior ceratobranchial among Actinopteri based on the formation of the hyoid arch elements. We also investigate the basibranchials and the closely associated unidentified gill-arch elements and show that they are not homologous. J. Morphol. 278:418-442, 2017. © 2017 Wiley Periodicals, Inc.
头部被认为是脊椎动物的主要新奇之处，并且与它们的进化成功直接相关。其形态、发育以及功能，例如在进食方面的功能，是进化生物学家主要感兴趣的内容。在本研究中，我们描述了西伯利亚鲟（Acipenser baerii）和俄罗斯鲟（A. gueldenstaedtii）颅骨和胸带的骨骼发育，这两种鲟鱼是水产养殖中常见的品种，并且在发育研究中越来越重要。本研究涵盖了神经颅、脏颅和皮颅以及胸带的真皮和软骨成分的发育，从孵化前幼体软骨细胞的首次凝聚到幼鱼早期阶段，并揭示了一种清晰的形成模式。耳囊、副索软骨和颅小梁是软骨化的最初中心，体长达到8.4毫米时出现。随后是下颌，接着是舌骨，再后来是鳃弓。牙齿早期在齿骨、皮腭骨和腭翼骨上形成，然后在口腔中稍后以背侧和腹侧齿板的形式出现。随着神经颅软骨化的进行，围绕大脑的一个囊和一个强壮的吻部形成。真皮骨化在背侧神经颅窗关闭之前就开始形成。软骨骨的软骨周骨化在个体发育过程中要晚得多才出现。我们的结果提供了有关某些元素同源性的数据，例如侧吻管骨，基于其形成顺序、位置和形态，我们认为它与其他辐鳍鱼类的眶前骨同源。基于舌弓元素的形成，我们还对辐鳍鱼类中后角鳃骨的同源性提出了疑问。我们还研究了基鳃骨和与之紧密相关的未确定鳃弓元素，并表明它们并非同源。《形态学杂志》278:418 - 442，2017年。©2017威利期刊公司
