Nikos Andreakis, Australian Institute of Marine Science - CERF Biodiversity Program 

Molecular phylogeography and evolutionary biology are being used by Hub postdoctoral researcher Nikos Andreakis to evaluate climatic and geological events responsible for the distribution of marine biota along the western and southern Australian coasts. 

Molecular phylogeography and evolutionary biology approaches are being applied to selected animal taxa, to describe their recent bio-geographical patterns of distribution and temporal levels of sequence divergence. For example, 77 families of over 500 nominal decapod crustacean species are today encountered along the tropical to temperate continental margin of Southern and central Western Australia; thirty-three per cent of those are thought to be new to science. Amongst them, decapod species of the families Chirostylidae and Galatheidae constitute an exceptional model system for evaluating historical processes responsible at the present observed distribution patterns of the Western Australian fauna. This is because Chirostylids and Galatheids are among the most numerous and diverse groups of crustaceans commonly encountered on seamounts, continental margins and shelf habitats at all depths. Moreover, they exhibit a high level of morphological diversity across their native distribution range, believed to be the result of a relatively old radiation event.

ChNikos Andreakis, Australian Institute of Marine Science - CERF Biodiversity Program irostylid and Galatheid squat lobsters have therefore been collected from several localities along the continental margin of central Western Australia and they have been morphologically identified to the species and genus levels by experts at Museum Victoria. A combination of mitochondrial and nuclear loci are used to infer robust phylogenies within families in order to (a) delineate taxonomic units and elucidate spatial patterns of diversity and distribution of the selected species, (b) formulate hypotheses of distribution on the basis of large or provincial scale geological events (such as historical changes in sea level and geomorphology), and (c) identify the evolutionary events responsible for the observed patterns by means of molecular clock estimates. These results will provide key insights on how contemporary biodiversity patterns may respond to current environmental changes.

So far, the application of mitochondrial markers has been successful in validating morphological taxonomy, revealing new species and delineating several cryptic morpho-species among Chirostylidae and Galatheidae of Western Australian origin. Since the phylogeographic and phylogenetic relationships of the Western Australia crustacean fauna to that of the remaining East and South-Western Pacific relatives are not fully resolved, a consequence of this project is to compare patterns and levels of diversity encountered in Western Australia and patterns of diversity recently described in South-Western Pacific scale within these two families to further explore the derivation and origins of the western Australian squat lobsters.

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*Nikos Andreakis completed his degree in Biological Sciences in 1999 at the University “Federico II” of Naples in Italy. He thereafter attained a one-year postgraduate student fellowship at the department of Agronomy for the development of molecular markers for DNA fingerprinting as indicators of quality for local agricultural products (supervisor R. Rao). Nikos started his studies in molecular ecology and genetics of marine species in 2002 at the “Stazione Zoologica A. Dohrn” of Naples (Italy). In 2006, he completed his PhD thesis in life sciences at the same institute (title: phylogeny, phylogeography and population genetics of the invasive red seaweed Asparagopsis (supervisors G. Procaccini, W.H.C.F. Kooistra, C.A. Maggs), awarded by the Open University of London (UK). After his PhD, Nikos stayed in Naples for two more years as a postdoctoral research fellow to investigate cryptic speciation events (by means of population genetics and phylogenetics) in the ascidian model-species Ciona intestinalis and for the development of isogenic/semi-isogenic lineages for microsatellite positional mapping in the same species (supervisor P. Sordino). He was then offered a 3 year CERF post-doctoral position at the Australian Institute of Marine Science in the laboratory of Dr Madeleine van Oppen. His main scientific interests, related to gene phylogeny and evolution, population genetics, phylogenetics, biogeography, cryptic speciation and adaptation, have been developed mainly within marine species.

References:

Poore, G.C.B., McCallum, A.S., and Taylor, J. 2008. Decapod Crustacea of the continental margin of south-western and central Western Australia: preliminary identifications of 524 species from FRV Southern Surveyor voyage SS10-2005. Museum Victoria Science Reports 11: 1–106.

Machordom A., Macpherson E. 2004. Rapid radiation and cryptic speciation in squat lobsters of the genus Munida (Crustacea, Decapoda) and related genera in the South West Pacific: molecular and morphological evidence. Molecular Phylogenetics and Evolution 33: 259-279.