Intertidal chitons (Mollusca: Polyplacophora) from the rocky coastline of Guerrero, México, with the description of a new species Author Reyes-Gómez, Adriana Author Flores-Garza, Rafael Author Galeana-Rebolledo, Lizeth Author Hernández-Vera, Gerardo Universidad de Guadalajara, Centro Universitario de Ciencias Biológicas y Agropecuarias, Departamento de Botánica y Zoología, Carretera a Nogales km. 15.5, Las Agujas Nextipac, Zapopan, Jalisco, C. P. 45110 México. Author Galván-Villa, Cristian M. Author Torreblanca-Ramírez, Carmina Author Flores-Rodríguez, Pedro Author García-Ibañez, Sergio Author Ríos-Jara, Eduardo text Zootaxa 2022 2022-06-23 5155 4 451 492 journal article 80415 10.11646/zootaxa.5155.4.1 2e18793c-3344-4542-92f3-1775f6276bb7 1175-5326 6691172 E6179D38-97E8-4EAB-8F28-8CF6E508C090 Acanthochitona arragonites ( Carpenter, 1857 ) Figures 2O , 13E–K , 14A–H Distribution. Throughout the Mexican Tropical Pacific, México . From Sonora , México to Salinas, Ecuador ( Watters 1990 ). Type specimens. According to Watters (1990) , lectotype by designation of Keen (1958:414) , BMNH 1857 /64.907. Type Locality. Mazatlán , Sinaloa , México . Material examined. 32 specimens , maximum size 9.9 mm long, 5.8 mm wide. G (n=4); P (n=2); R (n=3); S (n=2); U (n=5); F (n=1); E (n=2); N (n=6); J (n=4); I (n=2); A (n=1). Habitat. Acanthochitona arragonites occurs mostly in surf areas exposed to wave action. It was found on the underside of large rocks in protected cracks and crevices and is common under red, brown, and green algae. Adult and juvenile specimens are usually found together, but juvenile specimens were also collected at 3–6 m depths buried in sand and on the brown macro-alga Padina pavonica . We also collected adult specimens on medium-sized rocks buried in sand in a sample from 12 m depth ( Table 2 ). Remarks. Previous works on this species focused exclusively in describing and depicting the tegmentum pustule shape and patterns of aesthete openings ( Watters 1990 , 1991 ; Thorpe in Keen 1971 ) and a few other aspects of its morphology. In this study, we also describe and illustrate the radular teeth, which are characterized by small central and minor lateral teeth. The girdle spicules bear longitudinal ribs. According to Watters (1990) this species is known to be rare and almost absent in scientific collections. We believe that this lack of available specimens is due to the difficulty in accessing their habitat, which can be accessed only during the lowest tides.