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Juvenile morphology in baleen whale phylogeny
Cheng-Hsiu Tsai1, R Ewan Fordyce
1Department of Geology, University of Otago, Dunedin, New Zealand, cheng-hsiu.tsai@otago.ac.nz.
Die Naturwissenschaften
|August 2, 2014
Summary
Juvenile baleen whale morphology significantly impacts phylogenetic placement, with some species showing reliable signals while others yield misleading results. Understanding ontogeny is crucial for accurate evolutionary studies.
Area of Science:
- Evolutionary Biology
- Paleontology
- Zoology
Background:
- Phylogenetic reconstructions are influenced by ontogenetic changes in morphology.
- Juvenile morphology can affect the placement of extant species in phylogenetic analyses.
Purpose of the Study:
- To investigate how juvenile morphology of baleen whales (Cetacea: Mysticeti) influences their phylogenetic placement.
- To understand the impact of heterochrony on evolutionary patterns and phylogenetic signals.
Main Methods:
- Analysis of foetal/neonatal specimens of living baleen whale species.
- Comparative phylogenetic analysis of juvenile and adult morphologies.
Main Results:
- In Balaenopteridae (sei whale), juvenile morphology is distant from adult phylogenetic positions.
- In Cetotheriidae (pygmy right whale), juvenile morphology is close to adult phylogenetic positions.
- Heterochronic processes differentially influence juvenile morphology and phylogenetic placement.
Conclusions:
- Juvenile individuals from peramorphic acceleration clades may produce misleading phylogenies.
- Juvenile individuals from paedomorphic neoteny clades can provide reliable phylogenetic signals.
- This study aids in interpreting phylogenies that include immature fossil individuals.
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