Thursday, August 24, 2017


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Pachyseris (Agariciidae)

Welcome to the Pachyseris genus landing page. In this section, you will find general information about this genus and tips on how to identify it. If you are looking to confirm an observation made with the Coral Finder, use the image browser below to verify what you saw underwater.  The nature of this genus is highly distinctive, which means that it is unlikely to confuse it with other members of the group.

Despite its array of different growth forms, Pachyseris is a distinctive coral with a clear arrangement of septa, ridges and valleys, which focuses the eye when underwater and allows clear differentiation from other genera.

Vital Statistics

  • 5 species
  • Coral Finder p. 5c, 7, 16, 19, 20, 22
  • COTW – Vol 2 p. 224-231


Widespread in the Indo-Pacific.

ID Tips

Pachyseris grows into an array of leafy and plating forms, some of which may be highly contorted in shape.  It may be found in most reef zones and habitats.

(slide show with photos of different forms of Pachyseris including contorted forms)

The small, indistinct corallites form in valleys that run parallel to the edge of the colony.  The centre of each valley is marked by a beaded centreline of the polyp mouths.  At right angles to the valleys, fine septa form regular ribs that run out to the edges of the colony.  This pattern of valleys and septa is overlaid over any contortions in the colony surface.  Leafy and plating forms may be unifacial or bifacial.

Similar Genera

Pachyseris is a distinctive coral providing little confusion with other corals underwater.


There is an abundance of literature on the fish that associate with reefs and their coral builders.  Less well known are the smaller, less obvious inhabitants; Pachyseris provides solid substrate to a range of creatures, including two closely related species of copepod crustaceans, which inhabit the lower and upper surfaces of colonies respectively, suggesting a degree of specialisation to the individual environmental conditions of the two surfaces.  For more information on these coral-copepod associations head to Achituv et al., (2009) from the reading list below.

Taxonomic Changes

Learning Resources

Coral Hub

  • Agariciidae family page


Suggested Reading – Identification Tools

  • Dai, C.-F., & Lin, C.-H. (1992). Scleractinia of Taiwan: III. Family Agariciidae. Acta Oceanographica Taiwanica, 0(28), 80-101.
  • Veron, J. E. N. (1985). Corals of Australia and the Indo-Pacific. Sydney: Angus and Robertson.
  • Veron, J. E. N. (2000). Corals of the World. Melbourne: Australian Institute of Marine Science.

Suggested Reading – Other Topics

  • Achituv, Y., Tsang, L. M., & Chan, B. K. K. (2009). A new species of Cantellius and a redescription of C. sextus (Hiro, 1938) (Cirripedia, Balanomorpha Pyrgomatidae) from the elephant skin coral, Pachyseris speciosa (Dana, 1846) (Scleractinia, Agariciidae) from Taiwan. Zootaxa(2022), 15-28.