Serial sectioning of a nodule encapsulating an adult specimen of the arthrodire placoderm Watsonosteus fletti from the Eday Flagstone Formation (Givetian) in the Orcadian Basin of northern Scotland has revealed the presence of a number of embryos within the adult. This specimen represents the oldest known record of fossilized vertebrate embryos. Thin sections of two of the slices have revealed the detailed histological structure of embryonic plates in placoderms, showing that as previously deduced from visual examination, the outer and inner layers were the first to form. Gut contents preserved near the embryos show that the species had a varied diet, with dermal bone fragments from sarcopterygians and placoderms.

中文翻译：

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化石记录中最早的脊椎动物胚胎（中泥盆纪，吉夫田纪）

在苏格兰北部奥卡迪亚盆地，一个节节的成节结节封装了成虫标本Watsonosteus fletti的成年标本，该节标本来自Eday石板组（吉夫提安）。该标本代表了化石脊椎动物胚胎的最古老已知记录。切片的两个薄切片揭示了编轴器中胚胎板的详细组织学结构，显示出如先前从肉眼检查得出的那样，外层和内层是第一个形成的。保留在胚胎附近的肠内容物表明该物种的饮食结构各异，其中有来自翼翅目和鞭毛虫的真皮骨碎片。