Systematics of Damselfishes Author Tang, Kevin L. Author Stiassny, Melanie L. J. Author Mayden, Richard L. Author DeSalle, Robert text Ichthyology & Herpetology 2021 2021-05-05 109 1 258 318 http://dx.doi.org/10.1643/i2020105 journal article 53279 10.1643/i2020105 cf572f6b-8843-4383-85ce-ac9ea8515e87 2766-1520 7846738 Hemiglyphidodon . — This monotypic genus is characterized by a high gill-raker count that is unique in the family (.65 on first branchial arch vs.,40, in rest of family; Allen, 1975a, 1991; Masuda et al., 1984 ). Hemiglyphidodon plagiometopon occurs in the Indo-Australian Archipelago. It is another damselfish species that tends and harvests algal gardens ( Lassuy, 1980 ; Sammarco, 1983 ; Sammarco et al., 1986 ; Hoey and Bellwood, 2010 ; Hata and Ceccarelli, 2016 ) though there is evidence that it derives a large part of its diet from detritus which accumulates on the algae in its territory and not the algae itself ( Wilson and Bellwood, 1997 ). It seems that a strategy involving territorial defense and maintenance of an algal lawn, whether as a direct food source or as a collection system for food items, has evolved multiple times within Pomacentridae (e.g., herbivorous ‘‘ Chrysiptera ,’’ Dischistodus , Stegastes ). Even though there is little doubt about the nearest relatives of Hemiglyphidodon , its phylogenetic position within the tribe is unstable. We recover it as the sister group to the rest of Hemiglyphidodontini which agrees with some earlier works (e.g., Cowman and Bellwood, 2011; Rabosky et al., 2013 ; Lobato et al., 2014 ), but diasagrees with others which have shown it to be sister to Acanthochromis (Cooper et al., 2009; Mirande, 2016 ), Ambylglyphidodon ( Litsios et al., 2012a , 2012b ; Frédérich et al., 2013 ; DiBattista et al., 2016; Gaboriau et al., 2018 ; Rabosky et al., 2018 ), or both ( Quenouille et al., 2004 ).