Project Details
Projekt
Bone histology, body size and paleoenvironments of temnospondyls
Applicant
Professor Dr. Rainer Schoch
Subject Area
Geology
Term
since 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 508778113
The best-known group of early tetrapods are the temnospondyls, spanning some 215 million years from the Middle Carboniferous to the Early Cretaceous. They occupied a wide range of ecological niches, from aquatic over amphibious to fully terrestrial. Their wide morphological disparity is accompanied by large variation of adult body sizes (5 cm to 5 m). The questions of how certain temnospondyls reached their giant size, or how exceptionally tiny taxa evolved, have formed long-standing problems. Especially for giant taxa it is not clear how growth rate and lifespan interacted to permit the large body size. Some temnospondyls were also found to vary broadly between different localities that represent divergent paleoenvironments. Based on a range of such observations, an enhanced level of phenotypic plasticity has been inferred for some temnospondyls, and evidence has also bee identified on the bone histological level. Paleohistology, the study of fossilized bone tissues, provides the tools for addressing these problems. The analysis of the internal structure of bone can give answers about the age of an animal, growth rate, basic metabolic rate or adaptations to different modes of life. In Project A we will focus on characters of bone matrix and tissue types among long and dermal bones. The envisioned project aims at documenting and understanding the unusual extent of variation of bone histology in temnospondyls. It thereby integrates (1) histological data on the diversity of bone tissue in selected temnospondyl taxa with (2) data on variation in adult body size and (3) paleoenvironmental evidence of local life conditions derived from the study of fossillagerstätten. The overarching aim is to identify in which way body size influenced bone histology, and how large the influence of the environment on bone histology was in the studied taxa. This will help explain how the widely divergent body sizes evolved and what the range of phenotypic plasticity was in each taxon and paleoenvironment. To understand the range of inter- and intraspecific variability first the amount of intraskeletal (within one individual) histological variation has to be determined, as a second line of evidence the variation between taxa (intraspecific variation) will be studied and finally the impact of body size with the connection with paleoenvironment on bone histology. All obtained patterns will be mapped on a phylogeny of temnospondyls, with the aim to trace the evolution of body size and phenotypic plasticity in the group. Body size and plasticity form important traits for the reconstruction of life histories.
DFG Programme
Research Units
