Tectonic strain is ubiquitous in rock formations, leading to deformations, faults, and cracks at small as well as large scales. Fossils embedded in these strata will passively participate in these deformations, and have rarely been found undistorted. This affects ratios used in phylogenetic analyses. As a case study, diplodocid (Dinosauria: Sauropoda) cervical vertebrae were subjected to two different methods of retrodeformation, and the same methods were tested with a manually deformed digital model of a Dodo (Raphus cucullatus, Linnaeus, 1758) cervical vertebra. The results indicate that shape changes considerably in all dimensions. The tests showed that generally, retrodeformation restored symmetry, but increased deformation induced by compression. By comparing the trends obtained by the Raphus cucullatus analysis with the results from the diplodocid vertebrae, phylogenetic characters that are more prone to various types of deformations were identified. Phylogenetic analyses without these questionable characters generally yielded better resolution, shorter most parsimonious trees, and higher supporting values. Ratios used for character definitions, as well as other character information possibly affected by deformation, have to be applied very carefully, and highly susceptible ratios should be avoided a priori. As shown in this study, retrodeformation can work as a tool to identify such ratios and characters, but it has to be simultaneously tested with similar bones from extant taxa.

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The Late Jurassic Lourinhã Formation is known for its abundant remains of dinosaurs, crocodylomorphs and other vertebrates. Among this record are nine localities that have produced either dinosaur embryos, eggs or eggshell fragments. Herein, we describe and identify the first crocodiloid morphotype eggs and eggshells from the Lourinhã Formation, from five occurrences. One clutch from Cambelas, composed of 13 eggs, eggshell fragments from Casal da Rola and Peralta, one crushed egg and eggshells from Paimogo North, and four crushed eggs as well as eggshell fragments from Paimogo South. We observed and confirmed diagnostic morphological characters for crocodiloid eggshells and which are consistent with a crocodylomorph affinity, such as the ellipsoidal shape, wedge-shaped shell units, triangular extinction under cross-polarized light, and tabular ultrastructure. This material is distinctive enough to propose two new ootaxa within the oofamily Krokolithidae, Suchoolithus portucalensis, oogen. and oosp. nov., for the material from Cambelas, the most complete clutch known for crocodiloid eggs, and Krokolithes dinophilus, oosp. nov., for the remaining material. These are the oldest crocodylomorph eggs known, extending the fossil record for this group to the Late Jurassic. Furthermore, except for the clutch from Cambelas, the material was found with theropod eggs and nests, in the other four occurrences, which seem to suggest some form of biological relationship, still unclear at this point.