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Welcome to the world of Sulawesian freshwater crabs.
||Thanks to Christoph
Schubart I had the opportunity to conduct my Diploma thesis
on freshwater crabs of the Indonesian island Sulawesi during
2003/ 2004. The topic of the thesis was "Rekonstruktion der
Besiedlung der Malili-Seen (Sulawesi, Indonesien) durch Süßwasserkrabben
(Crustacea: Decapoda: Brachyura: Parathelphusidae)" and therefore
my main interest was - and still is - to reveal the phylogenetic
relationships within the endemic freshwater crab species of
the Malili lake system and between these and the species in
the surrounding rivers with the goal to get an idea how the
colonization of the lakes and speciation took place.
The reason for studying Sulawesi and the Malili lake system is
for one the special role of Sulawesi for the understanding of
the biogeography in this part of the world due to its situation
between the tectonic plates of Asia and Australasia and for the
other the high degree of endemism - not only of crab species,
but also other taxa like fishes, molluscs or shrimps - within
the ancient lakes of the Malili region, L. Matano, L. Mahalona
and L. Towuti. As it is for the crabs, there are right now five
species (Parathelphusinae) known belonging to three different
ecotypes, e. g. generalists, detritivores and molluscivores.
The methods I use to study these subjects are genetic sequence
analyses of mitochondrial (16S rDNA, Cytochrome oxidase I)
and nuclear (ITS 1, 5.8S rDNA, ITS 2) markers and morphometric
and morphological comparisons between species and populations.
Concerning the morphology, I am placing current emphasis on
the first gonopod G1, as it is considered a good character
for inferring phylogentic relationships.
Right now it looks like there are at least two independent
colonization events of the Malili lakes with the molluscivore
genus Syntripsa establishing in the lakes independently
from the unspecialized Parathelphusa species and the
detritivore Nautilothelphusa zimmeri. A peculiar result
of my work is the special relationship between N. zimmeri and P. ferruginea. In this case, contradictionary results
for the mitochondrial data on the one side and nuclear and
morphological data on the other side are at hand and probably
a case of mitochondrial introgression.
For the future, I want to extend my work on the
river forms of the whole island, to investigate further the phylogeny
of the crab fauna of the Malili and Poso regions and also different
adaptions of the ecotypes concerning feeding morphology.