Red Sea Acropora Workshop at Red Sea Research Center, King Abdullah University of Science and Technology

Most of the Australia based contingent of Project Phoenix (PP) has just returned from a workshop on the taxonomy of the Red Sea Acropora hosted by Professor Francesca Benzoni of the Red Sea Research Center at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia. The primary aim of the workshop was to revisit the status of the nominal species of Acropora in the Red Sea and identify topotypes for these species from within the Red Sea coral collection of Professor Michael Berumen and colleagues. The ultimate goal is to collect and describe the complete biodiversity of the Acropora in the Red Sea including what are bound to be numerous undescribed species.

The workshop started with talks from Pete Cowman, Andrew Baird, Tom Bridge and Sage Rasmussen, who presented various aspects of PP’s research on the phylogenomics and taxonomy of the Acropora. The talks were very well attended and the challenging message that can best be summarized by “Weird Al” Yankovic’s song “Everything you know is wrong” was surprisingly well received. There are lots of “giga-projects” underway in Saudi Arabia and it was pleasing that many of the scientists involved in these projects who attended the workshop recognize that getting the taxonomy right is an important part of understanding and managing the potential threats to the reef from these development projects.

Our study of the literature revealed that the Red Sea is the type location for 32 nominal species of Acropora. In the most recent taxonomic revision of the genus, only five of these species were considered valid, 20 were considered to be junior synonyms and 9 were not even mentioned (Wallace et al 2012). Our preliminary re-assessment of these nominal species based on the original descriptions and type material, painstakingly collated by Project Phoenix over the last 5 years, is that most of these synonymies are incorrect (Fig. 1). The only exceptions might be of some of the junior synonyms of Acropora pharaonis (Milne Edwards, 1860) and A. hemprichii (Ehrenberg, 1834). We suspect there are between 26-28 valid nominal species of Acropora in the Red Sea. Following our examination of our latest phylogeny, which includes 200 specimens of Acropora from the Red Sea, plus the skeletons and field images of the specimens in the Red Sea collection, we have identified 30 primary species hypotheses (PSH), only 8 of which could be matched with any of the type material. This is a strong indication that the other 22 are likely undescribed.

**Figure 1.** A re-examination of the type material is sufficient to suggest that *Acropora parapharaonis* Veron 2000 was incorrectly synonymised with *A. valida* (Dana 1846) by Wallace (1999). While the size and shape of the radials are similar, the gross morphology of the types are distinct as is the branch thickness. (a) the holotype of *A. parapharaonis* holotype G55786 (b) the holotype of *A. valid* (Dana 1846) USNM_272 (c) *A. parapharaonis* radial corallites (d) *A. valida* radial corallites.

Furthermore, we could only identify topotypes for 24 of the 32 nominal species (Fig. 2), indicating that there are at least 8 species of Acropora in the Red Sea that we have yet to sample. One striking example is Acropora capillaris (Klunzinger 1879; Fig. 3). As far as we can tell, Klunzinger’s type is the only hispidose Acropora colony every collected in the Red Sea.

**Figure 2.** The holotype of *A. parapharaonis* Veron 2000 (G55786) in the images on the left and its topotype from the Red Sea collection in the images on the right (SA0070).

Another extraordinary result from our phylogeny, which includes over 1200 specimens from throughout the Indo-Pacific, is that not one of these Red Sea PSH occur outside of the Red Sea. In other words, all the species of Acropora in our phylogeny from the Red Sea could be regional endemics, although further sampling from the Indian Ocean is required to establish the range extent of these species. In addition most of the species are undescribed. These are exciting times to be a coral taxonomist.

PP is grateful for the Red Sea Research Centre, KAUST for hosting the workshop, the HaBB lab group students and staffs for taking their time to prepare and engage in our exercises and discussions, and KAUST administrative staffs for helping organising the workshop.

**Figure 4**. Workshop participants from left to right. Roberto Arrigoni, Gus Crosbie, Andrew Baird, Francesca Benzoni, Sage Rasmussen, Pete Cowman, Nicolas Oury, Hanaka Mera, Tom Bridge.

Literature cited

Ehrenberg CG (1834) Die Corallenthiere des rothen Meeres: physiologisch untersucht und systematisch verzeichnet. Druckerei der Königlichen Akademie der Wissenschaften, Berlin.

Klunzinger CB (1879) Die Korallthiere des Rothen Meeres. Gutmann’schen Buchhandlung, Berlin.

Milne-Edwards H (1860) Histoire naturelle des coralliaires ou polypes proprement dits. Librairie Encyclopédique de Roret, Paris.

Wallace CC, Done BJ, Muir PR (2012) Revision and catalogue of worldwide staghorn corals Acropora and Isopora (Scleractinia: Acroporidae) in the Museum of Tropical Queensland. Mem Queensl Mus 57:1-255