LIB-Logo-red
Logo

Photo: UHH/CeNak, Martin Schwentner

Crustacea

Evolutionary systematics of Branchiopoda, especially Australian Notostraca and Spinicaudata

Australia harbours the world's greatest diversity of "large crayfish". Since many of the species are difficult to distinguish morphologically, this diversity was not recognised for a long time and thus the diversity of these crustaceans was greatly underestimated. Only the consistent use of an integrative taxonomic approach in the sense of an evolutionary systematics, including molecular and morphological characteristics and the consistent application of clearly defined species concepts, could reveal the actual diversity. This laid the foundation for further research into the systematics, ecology and evolution of the Australian branchiopod fauna.

The Australian continent is known for its vast deserts and its (semi)arid climate. These climatic conditions are perfect living conditions for branchiopod crustaceans, as they depend on the waters they inhabit to dry out regularly. Their drought-resistant permanent eggs enable long-term survival in these changeable and short-lived habitats. As a rule, these permanent eggs even require a preceding dry period in order to hatch in a subsequent wet period. The permanent eggs are also the only means of dispersal for these animals and they can be passively spread, e.g. by wind or animals (especially birds).



A typical Australian branchiopod community with several species of Anostraca, Notostraca (Triops) and Spinicaudata. Photo: UHH/CeNak, Martin Schwentner


By combining morphological and molecular genetic studies, we were able to show that Australia is a global diversity hotspot for branchiopods, with an estimated 80-100 Spinicaudata and about 20 Triops species. Especially in eastern Australia, the diversity seems to be particularly high: on an area of only about 100km2, more than 30 Spinicaudata species in 6 genera could be detected. This corresponds to about 15% of the known Spinicaudata species worldwide and to the diversity otherwise found within whole continents. Within the framework of current studies, further species are to be taxonomically recorded and the dispersal processes and distribution of the individual species explained in a historical, phylogeographical context. Of particular interest in this context are the passive dispersal potential of species and taxa on different geographical scales (both locally between neighbouring waters, but also intercontinental). Thus, initial studies suggest that intercontinental dispersal has played a central role in the present-day distribution of taxa.

One of the largest Spinicaudata species, Limndadopsis paradoxa, from Western Australia. Photo: UHH/CeNak, Martin Schwentner

In addition to the already established morphological and molecular genetic methods, the range of methods is being expanded to include next generation sequencing (especially ddRADSeq, transcriptome sequencing). These methods allow a much more detailed assessment of gene flow and genetic differentiation between populations and make it possible to investigate the influence of permanent eggs on population genetic processes, e.g. whether permanent eggs slow down microevolutionary processes such as genetic drift and thus delay the extinction of genetic lineages. Another major goal is to use these methods to identify and characterise the genomic changes associated with crucial events in branchiopod evolution. In this context, the evolution of Cladocera (water fleas) or Cladoceromorpha is of crucial importance, as their evolution was accompanied by drastic changes in reproduction (evolution of two different egg types), morphology and general lifestyle (successful colonisation of permanent waters).


Selected publications:

  • Meusel, F., Schwentner, M. (2017). Molecular and morphological delimitation of Australian Triops species (Crustacea: Branchiopoda: Notostraca)—large diversity and little morphological differentiation. Organisms Diversity & Evolution 17:137-156.

  • Schwentner, M., Timms, B.V., Richter, S. (2015): Spinicaudata (Crustacea: Branchiopoda) in Australia’s arid zone: Unparalleled diversity at regional scales and within water bodies. Journal of Crustacean Biology 35(3): 366-378.

  • Schwentner, M., Just, F., Richter, S. (2015): Evolutionary systematics of the Australian Cyzicidae (Crustacea, Branchiopoda, Spinicaudata) with the description of a new genus. Zoological Journal of the Linnean Society 173: 271-295.

  • Schwentner, M., Timms, B.V., Richter, S. (2014): Evolutionary systematics of the Australian Eocyzicus fauna (Crustacea: Branchiopoda: Spinicaudata) reveals hidden diversity and phylogeographic structure. Journal of Zoological Systematics and Evolutionary Research 52: 15-31.

  • Schwentner, M., Clavier S., Fritsch M., Olesen J., Padhye S., Timms, B.V., Richter, S. (2013): Cyclestheria hislopi (Crustacea: Branchiopoda): a group of morphologically cryptic species with origins in the Cretaceous. Molecular Phylogenetics and Evolution 66: 80-810.

  • Timms, B.V., Schwentner, M. (2012): A new genus and species of large limnadiid clam shrimp from Australia (Spinicaudata: Limnadiidae). Journal of Crustacean Biology 32(6): 981-990.

  • Schwentner, M., Timms, B.V., Richter, S. (2012): Flying with the birds? Recent large-area dispersal of four Australian Limnadopsis species (Crustacea: Branchiopoda: Spinicaudata). Ecology and Evolution 2(7):1605–1626.

  • Schwentner, M., Timms, B.V., Richter, S. (2012): Description of four new species of Limnadopsis from Australia (Crustacea: Branchiopoda: Spinicaudata). Zootaxa 3315:42-64.

  • Schwentner, M., Timms, B.V., Richter, S. (2011): An integrative approach to species delineation incorporating different species concepts: a case study of Limnadopsis (Branchiopoda: Spinicaudata). Biological Journal of the Linnean Society 104: 575-599.

  • Schwentner, M., Timms, B.V., Bastrop, R., Richter, S. (2009): Phylogeny of Spinicaudata (Branchiopoda, Crustacea) based on three molecular markers – An Australian origin for Limnadopsis. Molecular Phylogenetics and Evolution 53: 716-725.

  • Schwentner, M., Timms, B.V., Bastrop, R., Richter, S. (2008): Combining morphological and molecular characters to distinguish spinicaudatan species (Crustacea: Branchiopoda) with special focus on the male claspers. Journal of Morphology 269 (12): 1485-1486; published abstract

 
Lectures and posters:

  • Schwentner, M., Richter, S., Giribet, G. (2017) Trans-oceanic dispersal shaped global dirstribution of Branchiopoda. 110. Jährliches Treffen der Deutschen Zoologischen Gesellschaft (DZG) in Bielefeld, Poster

  • Schwentner, M., Richter, S. (2013) ‘Biogeographic history of the Australian Spinicaudata (Crustacea: Branchiopoda).’ XXXII. Willi Hennig Symposium in Rostock, Vortrag.

  • Meusel, F., Schwentner, M., Richter, S. (2013) ‘Diversität und Phylogeographie australischer Triops Arten.‘  16. deutschsprachige Crustaceologentagung, Greifswald, Poster

  • Schwentner, M., Clavier S., Fritsch M., Olesen J., Padhye S., Timms, B.V., Richter, S. (2013) ‘Cyclestheria hislopi (Crustacea: Branchiopoda): a group of morphologically cryptic species with origins in the Cretaceous.’ XXXII. Willi Hennig Symposium, Rostock, Poster

  • Tippelt, L., Schwentner, M., Richter, S. (2013) ‘Evolutionary systematics of Australian Eocyzicus (Branchiopoda: Spinicaudata) - two approaches for revealing and describing cryptic diversity.’ XXXII. Willi Hennig Symposium, Rostock, Poster

  • Schwentner, M., Clavier S., Fritsch M., Olesen J., Padhye S., Timms, B.V., Richter, S. (2012) ‘Cyclestheria hislopi (Crustacea: Branchiopoda): a group of morphologically cryptic species with origins in the Cretaceous.’ 105. Jährliches Treffen der Deutschen Zoologischen Gesellschaft (DZG) in Konstanz, Poster

  • Schwentner, M., Timms, B.V., Richter, S. (2011) ‘Vergleichende Phylogeographie australischer Muschelschaler (Branchiopoda: Spinicaudata) - Endemismus oder weiträumige Verbreitung.‘, 15. deutschsprachige Crustaceologentagung in Regensburg, Vortrag

  • Schwentner, M., Timms, B.V., Richter, S. (2010) ‘Phylogeography of Australian clam shrimp species (Branchiopoda: Spinicaudata) – regional endemism vs. wide dispersal.’ 103. Jährliches Treffen der Deutschen Zoologischen Gesellschaft (DZG) in Hamburg, Vortrag

  • Schwentner, M., Timms, B.V., Richter, S. (2010) ‘Biodiversity and population structure of Australian Spinicaudata (Crustacea: Branchiopoda).’ Australian Museum Sydney, Vortrag

  • Schwentner, M., Timms, B.V., Richter, S. (2010) ‘Integrative taxonomy and phylogeography of Australian Spinicaudata (Branchiopoda).’ 7th International Crustacean Congress 2010 in China, Vortrag

  • Schwentner, M., Timms, B.V., Bastrop, R., Richter, S. (2008) ‘Combining morphological and molecular characters to distinguish spinicaudatan species (Crustacea: Branchiopoda).’ 101. Jährliches Treffen der Deutschen Zoologischen Gesellschaft (DZG) in Jena, Vortrag

  • Schwentner, M., Timms, B.V., Bastrop, R., Richter, S. (2008) ‘Combining morphological and molecular characters to distinguish spinicaudatan species (Crustacea: Branchiopoda).’ Advances in Crustacean Phylogenetics in Rostock, Poster

  • Schwentner, M., Timms, B.V., Bastrop, R., Richter, S. (2008) ‘Combining morphological and molecular characters to distinguish spinicaudatan species (Crustacea: Branchiopoda).’ 1st International Congress on Invertebrate Morphology in Kopenhagen, Poster