First record of Acanthurus nigricans (Perciformes: Acanthuridae) and Cantherhines dumerilii (Tetraodontiformes: Monacanthidae) in Guerrero coast, Me ´ xico d.s. palacios-salgado 1 , a. ram irez-valdez 2 and a.a. rojas-herrera 3 1 Centro Interdisciplinario de Ciencias Marinas (CICIMAR-IPN), Departamento de Pesquerı ´as y Biologı ´a Marina, Apdo. Postal 592 0 La Paz, Baja California Sur, Me ´xico, C.P. 23000, 2 Facultad de Ciencias Marinas, Universidad Auto ´noma de Baja California, Carr. Tijuana-Ensenada Km. 107, Ensenada, Baja California, Me ´xico, CP 22800, 3 Unidad Acade ´mica de Ecologı ´a Marina, Universidad Auto ´noma de Guerrero, Apdo. Postal 1606, Acapulco, Guerrero, Me ´xico, C.P. 39390 The known geographic distribution of two reef fish species of Indo-Pacific affinity is increased: Acanthurus nigricans and Cantherhines dumerilii. These species are reported for the first time from the Acapulco coast, Me ´xico. Collection data, and morphometric and meristic characteristics of the studied specimens are presented. Keywords: Acanthurus nigricans, Cantherhines dumerilii, reef fish, Acapulco coast, Mexico The species Acanthurus nigricans (Linnaeus 1758), and Cantherhines dumerilii (Hollard 1854) are associated with rocky and coralline substrates. Both species are categorized as wandering residents of the tropical eastern Pacific (TEP) (Robertson et al., 2004), except for the Clipperton atoll, where they are remarkably abundant and are considered per- manent residents (Allen & Robertson, 1997). Specimens were captured in diurnal samplings, with a net placed between crevices on the rocky subsurface. Individuals were fixed in 10% formaldehyde buffered with sodium borate for subsequent preservation in 70% ethyl alcohol. Identity and distribution range of the species were determined using guides and fish keys for the region (Allen & Robertson, 1994; Bussing & Lavenberg, 1995; Grove & Lavenberg, 1997; Krupp, 1995; Thomson et al., 2000; Robertson & Allen, 2002). Finally the organisms were catalogued and deposited in the ichthyological collection of the Centro Interdisciplinario de Ciencias Marinas, IPN, in La Paz, Baja California Sur, (BCS) Me ´xico. Acanthurus nigricans was collected on 9 November 2000 in El Farallo ´n del Obispo (16º50 0 56 00 N 99º52 0 43 00 W), a small barren island commonly known as El Morro located 250 m off the coast north of Acapulco, Guerrero. The Cantherhines dumerilii specimen was collected in the subtidal of La Angosta beach (16º50 0 28 00 N 99º55 0 13 00 W) on 25 November 2000. In addition to the collected specimen, there is a visual record on 18 October 2001 of a pair of adults at La Roqueta island in Acapulco (16º49 0 25 00 N and 99º54 0 18 00 W) by Palacios-Salgado. The record of Acanthurus nigricans (Figure 1) corresponds to a juvenile individual of 151 mm overall length and 75 g weight (Table 1), presents dark coloration with a distinctive large white spot under the eye, and the caudal fin is white Fig. 2. Cantherhines dumerilii (Hollard, 1854) 337 cm total length caught in Acapulco coast (CICIMAR-CI 556). Fig. 1. Acanthurus nigricans (Linnaeus, 1758) 151 cm total length caught in Acapulco bay (CICIMAR-CI 555). Corresponding author: D.S. Palacios-Salgado Email: dpalacios@ipn.mx 1 Marine Biodiversity Records, page 1 of 2. #2007 Marine Biological Association of the United Kingdom doi:10.1017/S175526720700365X; Vol. 1; e35; 2008 Published online