Fig 1.
Showing the study area, location of crocodile, dinosaur egg nests and a polished eggshell section.
A. The study area (inset) and the location of crocodile (red star) and sauropod (red dots) nesting sites at Lameta Ghat (modified from Google Earth). B. Location of crocodile and dinosaur eggs, northern bank of Narmada River. C. Dinosaur nest of Megaloolithus jabulpurensis found in association with the crocodile nest at Lameta Ghat. D. Polished radial sections of Megaloolithus eggshell fragments in concentric arrangement (VPL/CCE - 5C).
Fig 2.
Photograph showing nest with eggs (LU/RS 01/9).
Fig 3.
A schematic diagram showing position of eggs in the nest.
Incomplete eggs shown by dotted lines.
Fig 4.
Showing the crocodylomorph eggshell outer, inner and radial surfaces.
A. Crocodylomorph eggshell (VPL/CCE 1–2) outer surface. B. Inner surface showing basal knobs (BK) and pore canal openings (PC). C. A portion of inner surface enlarged to show wedges radiating away from the basal knobs. D. A freshly broken radial surface showing trapezoid shaped shell unit with wedges radiating away from the basal knobs.
Fig 5.
Crocodylomorph eggshell sections under petrographic and scanning electron microscopes.
A. Crocodylomorph eggshell (VPL/CCE 3) section under crossed nicols showing floating quartz grain in calcareous matrix and horizontal accretion lines and the typical crocodilian inverted triangle extinction pattern. B. One portion of the eggshell (VPL/CCE 4) cut tangentially to show overlapping trapezoid shell units and irregular blocky extinction. C. Scanning Electron Micrograph of polished and etched eggshell section showing basal knob (BK) and smooth but uneven outer surface. D. The outer part of the same section enlarged showing herringbone pattern. E. inner layer showing wedges diverging outwards from the basal knobs (BK) and the pore canal (PC).
Fig 6.
Line drawing based on published papers showing basic structure of shell units found in birds, dinosaurs, turtles, lizards and crocodiles (not to scale).
Fig 7.
Comparison of the present eggshells with those a Pliocene Siwalik crocodile and dinosaur eggs of Megaloolithus jabulpurensis under crossed nicols.
A, The present eggshell thin section showing crocodilian features described above. B, Section of the fossil crocodylian eggshell (VPL/RP_RE-2) collected from the Siwaliks [41] exhibiting the characteristic horizontal accretion lines (HAL) and inverted triangle extinction (ITE) pattern. C, D and E, Megaloolithus jabulpurensis (VPL/CCE - 5C) showing fan shaped spheruliths, basal knobs (BK) sweeping extinction, arcuate accretion lines (AAL) and tuberculate outer surface. E, one of the spherolith further magnified.
Fig 8.
Scanning Electron Micrographs of Megaloolithus jabulpurensis (VPL/CCE - 5C) eggshells.
A, Fan shaped spherolith (SP) and pore canal (PC). B, Spongy layer of the spherolith magnified showing arcuate accretion lines and various fracture patterns.C, Spongy layer further magnified to show the typical “Herring-Bone” Pattern. D, Inner eggshell surface showing mamillae with resorption crater (RC). E, a pair of partly silicified fan-shaped speroliths with basal knobs. F, Basal knob (BK) magnified to show radiating patterns.