Data from: Normal table of embryonic development in the four-toed salamander, Hemidactylium scutatum

We present a complete staging table of normal development for the lungless salamander, Hemidactylium scutatum (Caudata: Plethodontidae). Terrestrial egg clutches from naturally ovipositing females were collected and maintained at 15 °C in the laboratory. Observations, photographs, and time-lapse movies of embryos were taken throughout the 45-day embryonic period. The complete normal table of development for H. scutatum is divided into 28 stages and extends previous analyses of H. scutatum embryonic development (Bishop, 1920; Humphrey, 1928). Early embryonic stage classifications through neurulation reflect criteria described for Xenopus laevis, Ambystoma maculatum and other salamanders. Later embryonic stage assignments are based on unique features of H. scutatum embryos. Additionally, we provide morphological analysis of gastrulation and neurulation, as well as details on external aspects of eye, gill, limb, pigmentation, and tail development to support future research related to phylogeny, comparative embryology, and molecular mechanisms of development.

本研究报道了有尾目（Caudata）无肺螈科（Plethodontidae）四趾螈（Hemidactylium scutatum）完整的正常发育分期表。本研究采集了自然产卵雌性个体所产的陆生产卵块，并于实验室15℃条件下进行培养。在为期45天的胚胎发育周期内，研究人员对胚胎开展了观察、拍照及延时摄像记录。本研究构建的四趾螈完整正常发育分期表共分为28个阶段，补充完善了此前关于该物种胚胎发育的相关研究（Bishop, 1920; Humphrey, 1928）。针对直至神经胚形成（neurulation）阶段的早期胚胎分期，本研究参考了非洲爪蟾（Xenopus laevis）、斑点钝口螈（Ambystoma maculatum）及其他蝾螈的既定分期标准；而晚期胚胎分期则基于四趾螈胚胎自身的独特形态特征制定。此外，本研究还对四趾螈的原肠胚形成（gastrulation）与神经胚形成（neurulation）过程进行了形态学分析，并详细描述了其眼睛、鳃、四肢、色素沉着及尾部发育的外部形态特征，可为后续系统发育学、比较胚胎学及发育分子机制相关研究提供有力支撑。