species: Acropora humilis in Lizard Island Field Guide (Lizard Island Field Guide)
Acropora humilis

©Andy Lewis: Pink colony of Acropora humilis on the reef flat near Palfrey Island

©Anne Hoggett: Acropora humilis at North Direction Island near Lizard Island. Identified by Zoe Richards.

©Andy Lewis: A colony of Acropora humilis showing a yellowish-brown colouration and typical short compact branches with large axial polyps
Kingdom Animalia
Phylum Cnidaria
Class Hexacorallia
Order Scleractinia
Family Acroporidae
Genus Acropora
Species Acropora humilis
Status near threatened



Distinguishing features

Neat, tapering, digitate branches with conical branch tips and huge axial corallites, radial corallites aligned in rows. (Contributed by Zoe Richards)

This species is digitate, with compact branches and a large axial polyp. Radial corallites are mostly one size, and increase only slightly in size down the branch. Colours include cream, pink, brownish-yellow, and blue-purple. (Contributed by Andy Lewis)


  • Size data has not been obtained.


Similar taxa


©Atlas of Living Australia: Australian distribution

Distribution and habitat preferences

Upper reef slopes, reef crests and shallow reef flats.

Abundant in shallow habitats around Lizard Island.


Like most Acroporidae, this species is a hermaphrodite broadcast spawner, releasing gametes shortly after dark in the few days after the full moon in the warmer months between November and February.

A. humilis is a member of a digitate species complex which also includes A. gemmifera, A. monticulosa, A. samoensis, and A digitifera. However Wolstenholme (2004) also recognised another 7 intermediate morphs at Lizard Island which may well prove to be seperate species. Persons interested in the correct identification of digitate Acroporid corals should consult this reference, in particular Table 1 which lists the morphological characteristics of each taxon.

Web resources


  • Abrego, D., M.J.H. Van Oppen and B.L. Willis (2009). Onset of algal endosymbiont specificity varies among closely related species of Acropora corals during early ontogeny, Molecular Ecology, 18: 3532-3543.
  • Aldredge, A.L. and J.M. King (1977). Distribution, abundance and substrate preference of demersal zooplankton at Lizard Island lagoon, Great Barrier Reef, Marine Biology, 41: 317-333. LIRS catalog number 1.
  • Alvarez-Noriega, M., A.H. Baird,2, M. Dornelas, J.S. Madin, V.R. Cumbo, and S.R. Connolly (2016). Fecundity and the demographic strategies of coral morphologies, Ecology, 97(12): 3485-3493. LIRS catalog number 2048.
  • View all references