Evolution of the Australian Onychophora

Morphological, chromosomal and behavioural diversification in the Australian velvet worms ('Peripatus').

The phylum Onychophora ('Velvet worms' or 'Peripatus') is of considerable scientific interest both because of its antiquity (there are fossils from the Burgess Shale, 540mya, that are strikingly similar to extant species) and its uncertain phylogenetic position.

In Australia, we have identified an enormous morphological, chromosomal and genetic radiation. The extent of this radiation is unclear, but we already recognise over 100 species (although barely half that number have been described). Work on their brain sturcture also reveals an unexpected level of complexity, and we have documented complex behaviours in these otherwise apparently simple organisms.

Relevant references

  • Ockman M.V., Rowell D.M. & Tait N.N. 2001 Phylogenetics of Planipapillus, lawn-headed onychophorans of the Australian Alps, based on nuclear and mitochondrial gene sequences. Mol. Phylo. Evol. 21: 103 - 106
  • Ockman M.V. & Rowell D.M. 2002 Episodic chromosomal evolution in Planipapillus: a phylogenetic approach to evolutionary dynamics and speciation. Evolution 56: 58 - 69
  • Rowell D.M, Rockman M.V. & Tait N.N. 2002 Extensive Robertsonian Rearrangement: Implications for the radiation and biogeography of Planipapillus Reid (Onychophora : Peripatopsidae). J. Zool. Lond. 257: 171 - 179
  • EINHARD J. & Rowell D.M. 2005 Social behaviour in an Australian velvet worm, Euperipatoides rowelli (Onychophora : Peripatopsidae). J. Zool. Lond. 267: 1 - 7
  • Strausfeld N.J., Strausfeld C.M., Loesel R., Rowell D.M. & Stowe S. (2006) Arthropod phylogeny: chelicerate brain organization in an onychophoran. Proc. Roy. Soc. Lond. Ser b. 273: 1857-1866
  • Strausfeld N.J., Strausfeld  C.M., Stowe S., Rowell D.M. & Loesel R. (2006) Organisation of neuropils in the brain of the onychophoran Euperipatoides rowelli and its evolutionary implications. Arthropod Structure and Development 35: 169 – 196.