• Head Neural Crest and Mesoderm Development
• Frogs and Tadpoles of Borneo
• Phylogeny of Frogs
• 3D Reconstruction in Morphology

Cranial neural crest and mesoderm development in Australian lungfish and amphibians.
Funding Organization: DFG, Germany

How did head neural crest and mesodermal development change in species spanning the water-land transition in the evolution of vertebrates? Furthermore, how did the morphological innovations present in the unique frog tadpole head, which is derived in many features in comparison to lungfish and salamanders, evolve?

We will document the developmental events which lead to the morphological diversity and morphological innovations that we observed in earlier work (evoltionary split of muscles; alterations in nerve paths). Detailed analyses of sequences of developmental events will allow us to identify potentially modular patterns of development in the formation of the vertebrate head and the observed structural complexes.

The development of cranial muscles and associated structures from paraxial mesoderm and neural crest are traced in lungfish, axolotl, and frog embryos. This will elucidate variation in developmental sequences and timing of these structures and the role of heterochronic shifts.

It is crucial for a comparative approach to unravel the developmental origin of the different cranial muscles. Judicious taxon sampling will allow us to assess and test muscle homologies in extant taxa and test our earlier hypotheses on cranial musculature evolution and morphological innovations. We investigate specifically the developmental origins of muscles and their relations to associated skeletal parts (neural crest). Muscles which were traditionally assigned to arch by their cranial nerve innervation but are actually located on a different visceral arch with their origins and insertions (e.g., angularis group in anurans) are of special interest.

Inventory and Biodiversity of the Frog Fauna of East Malaysia (Borneo) with emphasis on their larval forms. (Amphibia: Anura)

Frogs of Borneo Web Site

The project will produce an inventory of the tadpole fauna of selected study sites in East Malaysia (Sarawak and Sabah, Borneo). Currently our knowledge on the frogs of Borneo is incomplete and even less baseline data is known about their larval forms. We will generate detailed descriptions of tadpoles, which have not been described before and will revise earlier descriptions of known larvae. Specimens will be processed morphologically after colour photographs in life will were taken. Techniques of DNA taxonomy will be applied and geographic data will be recorded. All information will be databased. We will develop keys for identification both for use in the field and in the laboratory. Frog tadpoles have evolved a broad range of ecological types independent of the adult stage. We will map species richness and species communities along altitudinal and vegetational gradients. Habitat and microhabitat use will be recorded. The project is meant to be a fist step toward a long term monitoring of the selected study areas in tropical habitats of Borneo.

Phylogeny of frogs as inferred from primarily larval characters

Abstract
This paper presents larval evidence and evaluates its contribution to the discussion of frog phylogeny; 136 larval characters, 6 reproductive biology characters, and 14 adult morphology characters were scored for 81 frog and 4 caudate species. More than 90% of the data matrix entries represent original data derived from personal direct examination of specimens. Some larval characters are described for the ?rst time and many others have not been assessed for speci?c taxa or in a broad phylogenetic context before. Homoplasy appears common in this and other amphibian morphological data sets. The data supported and confirmed various wellknown clades, among others the Anura, Bufonidae, Ceratophryinae, Discoglossidae, Dendrobatidae, Hyperoliidae, Microhylidae, South American microhylids, Phyllomedusinae, Pseudinae, Pipoidea, Pipidae, and Scoptanura. The Ascaphidae was sister group to all other anurans and the Pipoidea was placed more basally than in some previous analyses. The Eurasian pelobatids formed a clade, whereas Spea and Pelodytes did not group robustly with them. Pelobatoid frogs emerged as a paraphyletic "transitional" assemblage including Heleophryne. The resolution of basal neobatrachian splits remained labile, although some subclades within the Neobatrachia were robustly supported. The "Hylidae" was paraphyletic, and hyline species were paraphyletic with respect to the Pseudinae. Hemisus clearly was in a clade with the Hyperoliidae and is proposed to be included in that family. Scaphiophryne was con?rmed as basal taxon within the Microhylidae. Compared to the larval stages of the most recent common ancestor of anurans, members of the scoptanura (microhylids except scaphiophrynines) have accumulated the highest number of apomorphic character states in anuran evolution.

3D Reconstruction in Morphology

Three-dimensional reconstruction of biological objects can be optional to visualize and communicate results or even indispensible to understand a structure.

There are many ways to do 3D reconstructions depending on the kind of data (histological sections, CT slices, episcopic methods), size of object, budget, principle (voxel versus surface models) and available hardware. There is no single perfect way to do 3D reconstructions; all procedures have their pros and cons.

We work with commercially available software packages. Great tools for interactive modeling are Alias Wavefront’s Studio and Maya, Maxon´s Cinema 4D, and 3ds max. Anatomical reconstruction software for perfectly aligned data are, for example, Surfdriver and Velocity2.