FIGURE 1. Map and location of the Cloche d’Or site, indicated by a star.
FIGURE 2. Photograph of the Cloche d’Or locality taken on 17 June 2021 during the main excavation activities. Most of the bone fragments (MNHNL LM226) were found in the exposed layer between the two arrows.
FIGURE 3. Stratigraphic log of the section at the Cloche d’Or locality.
FIGURE 4. Post-mortem scratch marks. Details of the bone surface of the possible surangular (A) and a vertebral fragment (B) of MNHNL LM226. These scratch marks with their characteristic radial shape are assignable to the ichnogenus Gnathichnus sp. and attributed to the grazing activities of regular echinoids. The orange arrows indicate some of best-preserved marks.
FIGURE 5. Location and anatomy of selected remains of the leptonectid ichthyosaurian MNHNL LM226. (A) silhouette with the location of selected remains; the total size of the animal is difficult to assess. (B) photograph and interpretation of the rostrum in ?anterior view. (C, D) rostrum in lateral views. (E) Detail of a tooth, magnified three times with respect to the other elements, showing the elongated crown and the near absence of striations on the root and acellular cementum ring. (F-H) fragmentary dorsal centrum in (F) medial, (G) lateroventral, (H) ventral views. (I) large rib fragment in internal view. (J) proximal cross-section of a rib, showing the 8-shaped cross-section. (K) cross-section of a rib, showing the 8-shaped cross-section. (L) distal cross-section of a rib showing the loss of one of the anterior/posterior grooves.
FIGURE 6. Diagnostic dental features of Early Jurassic ichthyosaurians with small and elongated tooth crowns. The distribution of concave ring at the level of the acellular cementum ring, which we term here “annulus” (indicated by orange arrows) appears restricted to leptonectids but are not fully expressed in all the teeth of an individual. (A) OUM J10305. (B) BRSMG Ce9856. (C) NHMUK R PV14370. (D) drawing extracted from Fraas (1892). (E) MNHNL LM226. (F) MNHNL TU112. (F) SMNS 81965. (H) MNHNL TV178.
