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A comparative study of eggshells of Gekkota with morphological, chemical compositional and crystallographic approaches and its evolutionary implications

Published on Jun 22, 2018in PLOS ONE2.776
· DOI :10.1371/journal.pone.0199496
Seung Im Choi3
Estimated H-index: 3
(SNU: Seoul National University),
Seokyoung Han4
Estimated H-index: 4
(SNU: Seoul National University)
+ 1 AuthorsYuong-Nam Lee15
Estimated H-index: 15
(SNU: Seoul National University)
Abstract
The Gekkota is an important clade in the evolution of calcified eggshells in that some of its families lay rigid eggshells like archosaurs. However, the fundamental differences and similarities between the mechanism of rigid eggshell formation of the Gekkota and Archosauria have not been investigated thoroughly due to the lack of knowledge of gekkotan eggshells. Here, we report for the first time a comprehensive analysis of morphological, chemical compositional, and crystallographic features of rigid and soft gekkotan eggshells. Exhaustive morphological description provided common characters for gekkotan eggshells, as well as unique features of each species. We found that elemental distribution of rigid gekkotan eggshells is different from that of avian eggshells, especially in the case of Mg and P. In addition, the crystallographic features (size, shape, and alignment of calcite grains) of gekkotan eggshells are completely different from those of archosaur eggshells. The result of this study suggests that soft gekkotan eggshells are morphologically more similar to tuatara eggshells rather than soft eggshells of derived squamates. The chemical compositional analysis suggests that the eggshell may act as a mineral reservoir for P and F as well as Ca. More importantly, all chemical compositions and crystallographic features imply that the gekkotan eggshell formation may begin at the outer surface and growing down to the inner surface, which is opposite to the direction of the archosaur eggshell formation. This character would be crucial for identifying fossil gekkotan eggs, which are poorly known in paleontology. All these lines of evidence support that soft gekkotan and tuatara eggshells share the primitive characters of all lepidosaurid eggshells. Finally, gekkotan and archosaur rigid eggshells represent a typical example of convergent evolution in the lineage of the Sauropsida.
  • References (65)
  • Citations (3)
References65
Newest
#1Miguel Moreno-Azanza (NOVA: Universidade Nova de Lisboa)H-Index: 12
#2Blanca Bauluz (University of Zaragoza)H-Index: 18
Last. Octávio Mateus (NOVA: Universidade Nova de Lisboa)H-Index: 26
view all 4 authors...
Introduction The Spheroolithidae oospecies Guegoolithus turolensis, putatively attributed to non-hadrosauroid styracosterns was first described in the Barremian of the Iberian Basin, and later reported in the Valanginian–Hauterivian of the Cameros Basin, with both occurrences separated by a few hundred kilometres but by over 10 million years.
5 CitationsSource
Abstract The majority of lizards and snakes lay flexible-shelled eggs with high water vapor permeability and which absorb water during incubation and increase in mass, volume, and surface area (water uptake is necessary for successful embryonic development). In contrast, one clade of gekkotans lay rigid-shelled eggs with low permeability which, like bird eggs, lose water during incubation and incubate successfully under low moisture conditions. Anecdotal accounts suggest that eggs of some New Ca...
2 CitationsSource
#1Edina Prondvai (UGent: Ghent University)H-Index: 11
#2Gábor Botfalvai (ELTE: Eötvös Loránd University)H-Index: 7
Last. Attila Ősi (MTA: Hungarian Academy of Sciences)H-Index: 18
view all 5 authors...
As a result of several years of screen-washing activity, a remarkable assemblage of eggshell fragments has been recovered from the Late Cretaceous vertebrate locality of Iharkut, Hungary. Detailed investigation of the assemblage by multiple visualization techniques (scanning electron microscopy, polarizing light microscopy, X-ray micro-computed tomography), quantitative morphometric analyses, and micro X-ray fluorescence spectrometry revealed a diverse composition of five different eggshell morp...
3 CitationsSource
#1Jyoti JeeH-Index: 1
Last. Gunanidhi SahooH-Index: 5
view all 4 authors...
We determined the sources of calcium for the developing embryo and the parallel changes in eggshell structure in the Indian agamid lizard Psammophilus blanfordanus . The developing eggs were opened at 0 (freshly laid), 10, 20, 30, 35, 38, and 40 days of incubation and at hatching (day 41) and subjected to chemical and structural analyses. The oval and flexible-shelled eggs had undergone significant changes in size (40% increase in length, 68% increase in breadth and 315% increase in weight) from...
1 CitationsSource
#1Miguel Moreno-Azanza (NOVA: Universidade Nova de Lisboa)H-Index: 12
#2Blanca Bauluz (University of Zaragoza)H-Index: 18
view all 5 authors...
Abnormalities in the histo- and ultrastructure of the amniote eggshell are often related to diverse factors, such as ambient stress during egg formation, pathologies altering the physiology of the egg-laying females, or evolutionarily selected modifications of the eggshell structure that vary the physical properties of the egg, for example increasing its strength so as to avoid fracture during incubation. When dealing with fossil materials, all the above hypotheses are plausible, but a detailed ...
7 CitationsSource
#1Gerald Grellet-Tinner (CONICET: National Scientific and Technical Research Council)H-Index: 2
#2Nigel A. Spooner (University of Adelaide)H-Index: 30
Last. Trevor H. Worthy (Flinders University)H-Index: 37
view all 3 authors...
Abstract The iconic Australian Genyornis newtoni (Dromornithidae, Aves) is the sole Pleistocene member of an avian clade now hypothesized to be alternatively in Anseriformes or the sister group of crown Galloanseres. A distinctive type of fossil eggshell commonly found in eroding sand dunes, has been referred to Genyornis newtoni since the 1980s. The 126 by 97 mm Spooner Egg, dated at 54.7 ± 3.1 ka by optical dating of its enclosing sediments, is a complete specimen of this eggshell type that wa...
20 CitationsSource
#1Alberto Pérez-Huerta (UA: University of Alabama)H-Index: 18
#2Yannicke DauphinH-Index: 36
The structure and composition of the eggshells of two commercial species (guinea fowl and greylag goose) have been studied. Thin sections and scanning electron microcopy show the similarity of the overall structure, but the relative thickness of the layers differs in these two taxa. Atomic force microscopy shows that the different layers are composed of rounded, heterogeneous granules, the diameter of which is between 50 and 100 nm, with a thin cortex. Infrared data and thermogravimetric analyse...
9 CitationsSource
#1Zoltán Csiki-Sava (UB: University of Bucharest)H-Index: 10
#2Mátyás VremirH-Index: 8
Last. Radu. TotoianuH-Index: 2
view all 8 authors...
Abstract The latest Cretaceous continental vertebrate faunas of the wider Transylvanian area figured prominently in discussions concerning the Cretaceous–Paleogene Boundary (K-Pg) events when they were first described by Nopcsa between 1897 and 1929, because they were assumed to be late Maastrichtian in age. Subsequently their age was reconsidered as early Maastrichtian, and were thus regarded of lesser importance in understanding the K-Pg boundary events in Europe and worldwide. Moreover, Trans...
22 CitationsSource
Last. B. Bauluz LázaroH-Index: 1
view all 7 authors...
Here we describe the new fossil site of El Horcajo in the vicinity of Trevijano (La Rioja, Spain). It is located in the palustrine facies of the Enciso Group (Cameros Basin). This new locality has provided dozens of eggshell fragments, together with other vertebrate remains and charophyte fructifications, which allow dating of the locality as Valanginian-Hauterivian. Five ootaxa have being recognized: 1) the Spheroolithidae Guegoolithus turolensis; 2) a surprisingly thick Prismatoolithidae indet...
2 Citations
The majority of lizards and snakes produce permeable parchment-shelled eggs that require high moisture conditions for successful embryonic development. One clade of gekkotan lizards is an exception; females produce relatively impermeable rigid-shelled eggs that normally incubate successfully under low moisture conditions. I tested the hypothesis that the rigid-shell increases egg survival during incubation, but only under low moisture conditions. To test this hypothesis, I incubated rigid-shelle...
3 CitationsSource
Cited By3
Newest
#1Seung Hong Choi (SNU: Seoul National University)H-Index: 46
#2Sung Keun Lee (SNU: Seoul National University)
Last. Yuong-Nam Lee (SNU: Seoul National University)H-Index: 15
view all 5 authors...
Raman spectroscopy has been widely used in micropalaeontology and organic geochemistry to identify carbonaceous materials and evaluate their thermal maturity in fossils or metasedimentary rocks. Meanwhile, fossil egg researches have mostly focused on biomineralized calcite, but preserved carbonaceous (or possibly organic) materials inside the eggshells have been usually neglected until recently. Here we report an enigmatic egg from the Wido Volcanics (Upper Cretaceous) of South Korea that was an...
Source
#1Seung Hong Choi (SNU: Seoul National University)H-Index: 46
#2Miguel Moreno-Azanza (NOVA: Universidade Nova de Lisboa)H-Index: 12
Last. Yuong-Nam Lee (SNU: Seoul National University)H-Index: 15
view all 5 authors...
1 CitationsSource
#1Seung Im Choi (SNU: Seoul National University)H-Index: 3
#2Yuong-Nam Lee (SNU: Seoul National University)H-Index: 15
Abstract Among non-avian maniraptoran eggshells, oofamilies Prismatoolithidae and Elongatoolithidae are usually associated with troodontid and oviraptorosaur dinosaurs, respectively. However, dromaeosaurid eggshells are poorly known so far except for one possible Deinonychus egg associated with the gastralia of Deinonychus. Since then, some Deinonychus eggshell-like non-prismatoolithid and non-elongatoolithid maniraptoran eggshells have been reported including oogenera Reticuloolithus and Montan...
Source
#1Seung Im Choi (SNU: Seoul National University)H-Index: 3
#2Seokyoung Han (SNU: Seoul National University)H-Index: 4
Last. Yuong-Nam Lee (SNU: Seoul National University)H-Index: 15
view all 3 authors...
3 CitationsSource
#1Noe-Heon Kim (SNU: Seoul National University)H-Index: 2
#2Seung Im Choi (SNU: Seoul National University)H-Index: 3
Last. Yuong-Nam Lee (SNU: Seoul National University)H-Index: 15
view all 4 authors...
Abstract The Cretaceous oofamily Faveoloolithidae has a unique shell unit and pore canal system that clearly differs from most of the extant and fossil eggshells. Despite its distinctiveness, morphological (micro- and ultrastructural) and crystallographic features of the Faveoloolithidae are poorly known. Here we report a new faveoloolithid nesting ground from the Upper Cretaceous siltstones within the Daeri Andesite of the Wido Volcanics (Coniacian–Santonian), South Korea. Forty-one of the same...
2 CitationsSource