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Processing Embryo, Eggshell, and Fungal Culture for Scanning Electron Microscopy
Published on: August 16, 2019
Testing phylogenetic implications of eggshell characters in side-necked turtles (Testudines: Pleurodira)
1Department of Zoology, University of Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany. jadawinkler@hotmail.com
Zoology (Jena, Germany)
|April 8, 2006
Summary
The study examines eggshell morphology in side-necked turtles (Pleurodira) for phylogenetic insights. While many eggshell traits lack phylogenetic signal, some features support specific turtle clades, aiding systematic understanding.
Area of Science:
- * Paleontology and Systematics
- * Herpetology and Reproductive Biology
Background:
- * Amniote egg and eggshell morphology offer insights into reproductive biology and systematics.
- * Fossil bird and dinosaur egg research is extensive, but extant sauropsid egg knowledge is limited.
- * Side-necked turtles (Pleurodira) represent an understudied group regarding eggshell character utility.
Purpose of the Study:
- * To test and discuss the utility of eggshell characters for phylogenetic analyses in extant Pleurodira.
- * To examine the diversity of egg ultrastructure within several Pleurodira species.
- * To reconstruct ancestral character states using eggshell morphology.
Main Methods:
- * Documented gross morphology and eggshell ultrastructure of 12 extant side-necked turtle species.
- * Utilized scanning electron microscopy for detailed ultrastructural examination.
- * Scored 13 eggshell characters, mapped them onto a composite phylogeny, and reconstructed ancestral states.
Main Results:
- * Many eggshell characters exhibited no significant phylogenetic signal when compared to random trees.
- * Identified conservative, clade-supporting features within Pleurodira.
- * Supported the Elseya-Emydura clade (Australasian chelids) with two characters, potentially two more.
- * Found three characters supporting South American chelids' monophyly, but two suggested Hydromedusa exclusion.
Conclusions:
- * While not universally informative, specific eggshell characters provide valuable phylogenetic signals for Pleurodira.
- * Demonstrated the potential of eggshell morphology to support systematic hypotheses in turtles.
- * Highlighted the need for further research into eggshell characters for understanding turtle evolution.
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