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Xanthichthys mento (Jordan & Gilbert, 1882). Crosshatch Triggerfish or Redtail Triggerfish. To 30 cm (11.7 in) TL (Randall 1996). Tropical Pacific Ocean; scattered locations in the eastern Pacific including Ventura, southern California (Miller and Lea 1972), Isla Guadalupe, Rocas Alijos, tip of Baja California, and Colombia (Robertson and Allen 2015). Benthic; depth: surface to 158 m (518 ft) (min.: Eschmeyer and Herald 1983; max.: Weijerman et al. 2019)., Published as part of Love, Milton S., Bizzarro, Joseph J., Cornthwaite, Maria, Frable, Benjamin W. & Maslenikov, Katherine P., 2021, Checklist of marine and estuarine fishes from the Alaska-Yukon Border, Beaufort Sea, to Cabo San Lucas, Mexico, pp. 1-285 in Zootaxa 5053 (1) on page 224, DOI: 10.11646/zootaxa.5053.1.1, http://zenodo.org/record/5578008, {"references":["Randall, J. (1996) Shore Fishes of Hawaii. National World Press, Vida.","Miller, D. J. & Lea, R. N. (1972) Guide to the coastal marine fishes of California. California Department of Fish and Game Fish Bulletin, 157.","Robertson, D. R. and Allen, G. R. (2015) Shorefishes of the Tropical Eastern Pacific: an Information System. Version 2.0 (2008). Smithsonian Tropical Research Institute, Balboa. http: // biogeodb. stri. si. edu / sftep / en / pages","Eschmeyer, W. N. & Herald, E. S. (1983) A Field Guide to Pacific Coast Fishes of North America from the Gulf of Alaska to Baja California. Houghton Mifflin, Boston.","Weijerman, M., Gruss, A., Dove, D., Asher, J., Williams, I. D., Kelley, C. & Drazen, J. (2019) Shining a light on the composition and distribution patterns of mesophotic and subphotic fish communities in Hawai'i. Marine Ecology Progress Series, 630, 161 - 182. https: // doi. org / 10.3354 / meps 13135"]}

The reproduction of Rhinecanthus aculeatus (Linnaeus, 1758), a tropical Indo-Pacific reef fish, occurs around the full and new moon (Kuwamura 1997). Spawning begins 16 to 45 min before the sunrise. The courtships begin 7 to 27 min before the spawning. A specific behaviour of the courtships is when the male places its rostrum against the caudal peduncle of the female (Kuwamura 1997). Observations have been recorded in the lagoon of Tiahura [shallow sandy area (0.5 - 2 m deep) with algae Hypnea spinella (C.Agardh) Kutzing, 1847 - Moorea, French Polynesia; 17°29′27′ S, 149°53′32″O] in March and April 2015. Fifteen R. aculeatus (five males and ten females) lived in this area where the males have territories, which included the subterritories of the females. During video-recorded courtships, in addition to the behaviour described by Kuwamura (the nuzzling), two new behaviours have been observed: circling and touching. During the circling, the male and the female swim to the surface in progressively larger circles (Fig. 1). The circling behaviour has been observed in other Balistidae such as Pseudobalistes flavimarginatus (Ruppell, 1829) and Balistapus undulatus (Park, 1797) (Lobel and Johannes 1980). During the touching, the abdomens of the male and the female’s touch each other without gametes emission (Fig. 2). The touching has been reported for Xanthichthys mento (Jordan and Gilbert 1882) (Kawase 2003). Although Balistidae present different reproductive strategies, they have common reproduction features, such as the time and the day of hatching and spawning (Kawase 2003). Our observations are innovative because the courtship of R. aculeatus is more complicated than previously described. This result suggests, thus, that Balistidae have also some common courtship behaviour features. These behaviours may facilitate the release of gametes, as with the nuzzling (Kuwamura 1997) or can convince the partner to mate. We do not know if these patterns are phylogenetically related. But as the egg care strategy of Balistidae (biparental vs maternal) appears to be related to the distribution of food and breeding sites, more than by the phylogeny (Kuwamura 1997), more studies on this topic will be useful to better understand the establishement of these behaviours.

Reproductive ecology of the crosshatch triggerfish, Xanthichthys mento (Balistidae) was studied at Hachijojima, Izu Islands, Japan. Males established territories and repeatedly chased females passing nearby. There were 1–3 females in each male's territory before spawning and during egg care. This species spawned in pairs on the sandy bottom. Eggs were scattered and attached to sand particles. Females care for the eggs by blowing water on them and guarding them against intruders, while males helped in guarding. Thus, biparental egg care was observed for 2 days until hatching. Both the males and females disappeared from the territories after the egg care. The reproductive ecology of this species is compared with that of other balistids and the unique features of X. mento are described.