Kun GUO,Jun ZHONG,Li MA,et al.Chemical Composition and Crystal Structure of the Eggshell of the Green Crested Lizard Bronchocela cristatella (Agamidae)[J].Asian Herpetological Research(AHR),2021,12(4):331-336.[doi:10.16373/j.cnki.ahr.210016]
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Chemical Composition and Crystal Structure of the Eggshell of the Green Crested Lizard Bronchocela cristatella (Agamidae)
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Asian Herpetological Research[ISSN:2095-0357/CN:51-1735/Q]

2021 VoI.12 No.4
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Chemical Composition and Crystal Structure of the Eggshell of the Green Crested Lizard Bronchocela cristatella (Agamidae)
Kun GUO1 Jun ZHONG1 Li MA2 Yongpu ZHANG1 and Xiang JI1*
1 College of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, Zhejiang, China
2 Faculty of Ecology, Lishui University, Lishui 323000, Zhejiang, China
agamid lizard aragonite calcite crystal structure eggshell elemental bonding states X-ray diffractometer X-ray photoelectron spectroscopy
The majority of extant reptiles are oviparous and produce eggs with three major components: embryo, yolk, and eggshell. The eggshell is species-specific and more diverse in squamate reptiles than in other amniote taxa. Here, we study the crystal structure, chemical composition, and bonding states of the eggshell of the green crested lizard Bronchocela cristatella. X-ray diffractometer (XRD) analysis showed the existence of two clearly defined and distinguishable crystalline phases, aragonite and calcite. Using the XRD data and a unit cell refinement routine, we identified two sets of cell parameters: a = 4.956 ?, b = 7.965 ?, and c = 5.734 ? for the aragonite phase; a = 4.987 ?, b = 4.987 ?, and c=17.056 ? for the calcite structure. We used x-ray photoelectron spectroscopy to examine detailed elemental composition and bonding states and found that the eggshell was composed primarily of elements C, N, Ca, and O, with C, N and O bonded to various types of hybridization in the protein of the eggshell membrane. The Ca:C:O ratio for the calcium carbonate yielded a value of ~7:8:21, which is close to the expected stoichiometric value of CaCO3.


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Last Update: 2021-12-25