Dinosaurs nesting on tidal flats

Abstract

The discovery of a dinosaur clutch in Upper Cretaceous tidal flat deposits in the Tremp Formation in Biscarri, Isona (Lleida, Spain), provides insight into the mode of life of some dinosaurs. The clutch occurs in grey marls that were originally waterlogged, muddy sediments. The seven elongated eggs are parallel to each other and with their long axis almost vertically oriented. A mound-nest is inferred in contrast to hole-nest described so far for similar eggshell types. The permeability of the eggshell (oospecies Megaloolithus siruguei) was highly enhanced by a braided network of multicanaliculate pore canals. The nest style, eggshell porosity and tidal flat environment point to a periaquatic habitat for these dinosaurs. A modern analogue occurs in crocodiles, alligators and some birds living in periaquatic environments, with nesting on plant-mounds above waterlogged soils or even on floating vegetation.

Taphonomical and palaeoecological investigation of the Late Cretaceous (Maastrichtian) Tuştea vertebrate assemblage (Romania; Haţeg Basin) - insights into a unique dinosaur nesting locality

“…Selecting similar palaeoenvironments for nesting would be also expected as it appears that both titanosaurs and hadrosauroids had roughly similar nesting strategies, characterized by: colonial nesting; moderate-sized (10-22 cm in maximum diameter, but usually ranging between 12-16 cm) subspherical eggs laid in clutches that are only very diffusely organised, sometimes with two partly overlapping levels of eggs; and clutches covered most probably by dirt and/or vegetation mounds (e.g., Horner, 2000;Grellet-Tinner et al, 2006). Furthermore, both of these taxa (or eggs referred to them) appear to have had rather wide environmental flexibility in nesting site selection (e.g., Horner, 1982Horner, , 1999López-Martínez et al, 2000;Fanti and Miyashita, 2009;Sellés, 2012;García et al, 2015). All of these characteristics were already noted in the case of the megaloolithid eggs from the Hațeg Basin .…”

“…It should be noted nonetheless, that despite the fact that Megaloolithus eggs from northern Spain, southern France or India are being commonly attributed to titanosaurian sauropods (Buffetaut and Le Loeuff, 1994;Mohabey, 1996), there is no direct proof to support this referral (e.g., Sander et al, 1998;López-Martínez et al, 2000). Recently it has been also suggested that in western Europe,…”

“…To our knowledge, there is no reported dinosaur nesting ground worldwide where eggs, nests and hatchlings of a particular taxon are preserved together, in same horizon, with bones of other non-prey dinosaur taxa (compare with, e.g., Horner, 1994;Sahni and Khosla 1994;Mohabey, 1996;Sahni, 1997;López-Martínez et al, 2000;Chiappe et al, 2005;Sellés et al, 2013). …”

Porosity of Late Paleocene Ornitholithus eggshells (Tremp Fm, south-central Pyrenees, Spain): Palaeoclimatic implications

“…Most of them are from Upper Cretaceous coastal deposits of the interfingering Aren and lower Tremp Fms (Sanz et al, 1995;López-Martínez et al, 2000;Díaz Molina et al, 2007). The abundance of fossil eggshell sites from Upper Campanian to Upper Maastrichtian deposits contrasts with its rarity or absence from the uppermost part of Maastrichtian and most Palaeocene deposits.…”

Lower Eocene Crustacean Burrows (Israel) Reflect a Change from K- to r-Type Mode of Breeding Across the K-T Boundary Clarifying the Process of the End-Cretaceous Biological Crisis

“…This selective elimination of the most skillful predators resulted from their early ontogenetic stage. Dinosaurs and pterosaurs were oviparous, laying 1-7 eggs (or more) in nests on a rather flat land, such as sea-shores (Sanz et al, 1995), tidal flats (López-Martínez et al, 2000) and beside estuaries, lagoons, marshes and fluvial plains (Vianey-Liaud & Lopez-Martinez, 1997). Despite brood-care by the adults, the eggs and the hatchlings were frequently exposed to potential predators and could be snatched from the nest or consumed on site after the distraction of the parent.…”