species: Macrophiothrix rhabdota in taxonomy (Lizard Island Field Guide)
Macrophiothrix rhabdota

©Anne Hoggett: Same specimen of Macrophiothrix rhabdota as below. Note three pale lines on arms and shape of the five pairs of radial shields on the disc.

©Anne Hoggett: Macrophiothrix rhabdota found under a slab of rubble at the base of the reef slope at Pidgin Point, February 2009

©Anne Hoggett: Disc of a different specimen of Macrophiothrix rhabdota at Lizard Island. Note┬áspinelets on disc and shorter ones on radial shields.
Kingdom Animalia
Phylum Echinodermata
Class Ophiuroidea
Order Ophiurida
Family Ophiotrichidae
Genus Macrophiothrix
Species Macrophiothrix rhabdota



Distinguishing features

Macrophiothrix species are difficult to distinguish in the field because microscopic examination of characters is necessary. Most species in the genus are large (disc diameter can be more than 20 mm), have very long arms, and live on soft sediment under slabs of rubble.

Macrophiothrix rhabdota is probably the most readily distinguished in the field of all the Macrophiothrix species - it has a distinctive pattern of three pale longitudial lines on the dorsal arm surface. Disc diameter reaches 19 mm and the arms are 10 to 14 times that length. Radial shields (five pairs of conspicuous triangular disc plates) have the widest point about half way along the length and they are covered in rough stumps. The rest of the disc surface is also covered in rough stumps that mostly have three points when viewed with a microscope. Dorsal arm plates are wide and fan-shaped. As well as the distinctive three longitudinal stripes, the arms are also transversely banded with darker patches as shown in the photo.


  • Size data has not been obtained.

Depth range

  • Depth range data is not yet available.



©Atlas of Living Australia: Australian distribution

Web resources


References that assist with identification

  • Clark, A.M. and F.W.E. Rowe (1971). Monograph of shallow-water Indo-west Pacific echinoderms British Museum (Natural History), London.
  • Coleman, N. (2007). Sea Stars: Echinoderms of the Asia/Indo-Pacific Neville Coleman's Underwater Geographic, Springwood, Qld. Australia.
  • Hoggett, A.K. (1990). Taxonomy and systematic position of the brittlestar genus Macrophiothrix H.L. Clark (Echinodermata: Ophiuroidea). PhD thesis, University of Queensland. LIRS catalog number 680.
  • View all references