Geometric morphometrics of endophytic oviposition traces of Odonata (Eocene, Argentina)

ROMERO-LEBRÓN, EUGENIA; GLEISER, RAQUEL M.; PETRULEVICIUS, JULIÁN F.

Royal Society Open Science

The Royal Society Publishing

Año: 2020 vol. 7

2054-5703

The insertion of the Odonata ovipositor in the plant tissuegenerates a scar that surrounds the eggs (trace). In insects,individual egg traces are known to vary in size, but theirvariation in individual shape is mostly unknown. Twentyfourspecimens 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 andsize of a large number of individual Odonata endophytic eggtraces was carried out using traditional (general and mixedlinear models) and geometric morphometrics (Fourierelliptical series) to elucidate whether there are changes in sizeor shape of the individual endophytic egg traces associatedwith the substrate used at the time of oviposition, if theLower Eocene traces have varied in relation to those ofthe Middle Eocene, and if the ichnological classification(Paleoovoidus arcuatus, P. bifurcatus and P. rectus) reflects suchvariations. We found differences in size ( p < 0.05), but not inshape, in relation to the variables studied. This could reflectthat the shape of Odonata eggs (inferred from the traces),unlike their size, could have a strong evolutionary constraintalready observed since the Eocene.