Romero-Lebrón Eugenia, Gleiser Raquel M, Petrulevičius Julián F
Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales (IMBIV, UNC-CONICET), 5000 Córdoba, Argentina.
División Paleozoología Invertebrados, Facultad de Ciencias Naturales y Museo (UNLP), and CONICET, 1900 La Plata, Buenos Aires, Argentina.
R Soc Open Sci. 2020 Dec 16;7(12):201126. doi: 10.1098/rsos.201126. eCollection 2020 Dec.
The insertion of the Odonata ovipositor in the plant tissue generates a scar that surrounds the eggs (trace). In insects, individual egg traces are known to vary in size, but their variation in individual shape is mostly unknown. Twenty-four specimens were obtained from the Laguna del Hunco (Lower Eocene, Chubut) and Río Pichileufú (Middle Eocene, Río Negro), Argentina, which had 1346 oviposition traces (MEF Collection). For the first time, a study of the shape and size of a large number of individual Odonata endophytic egg traces was carried out using traditional (general and mixed linear models) and geometric morphometrics (Fourier elliptical series) to elucidate whether there are changes in size or shape of the individual endophytic egg traces associated with the substrate used at the time of oviposition, if the Lower Eocene traces have varied in relation to those of the Middle Eocene, and if the ichnological classification (, and ) reflects such variations. We found differences in size ( < 0.05), but not in shape, in relation to the variables studied. This could reflect that the shape of Odonata eggs (inferred from the traces), unlike their size, could have a strong evolutionary constraint already observed since the Eocene.
蜻蜓目昆虫产卵器插入植物组织会形成围绕卵的疤痕（痕迹）。在昆虫中，已知单个卵痕大小各异，但它们个体形状的变化大多未知。从阿根廷的拉古纳德洪科（始新世早期，丘布特省）和皮奇莱乌富河（始新世中期，内乌肯省）采集了24个标本，这些标本有1346个产卵痕迹（MEF收藏）。首次使用传统方法（一般线性模型和混合线性模型）和几何形态计量学（傅里叶椭圆级数）对大量单个蜻蜓目内生卵痕的形状和大小进行研究，以阐明单个内生卵痕的大小或形状是否随产卵时所使用的基质而变化，始新世早期的痕迹与始新世中期的痕迹相比是否有所不同，以及遗迹学分类（、和）是否反映了这种变化。我们发现，在所研究的变量方面，大小存在差异（<0.05），但形状没有差异。这可能反映出，从痕迹推断，蜻蜓目昆虫卵的形状与其大小不同，自始新世以来可能就已经受到很强的进化限制。
