Medusozoans from the Mexican Pacific: a review based on historical literature and recent observations Author Estrada-González, Mariae C. Author Agüero, José Author Mendoza-Becerril, María A. text Journal of Natural History 2023 2023-06-15 57 1 784 853 http://dx.doi.org/10.1080/00222933.2023.2214967 journal article 60720 10.1080/00222933.2023.2214967 a9bb27e7-4ac2-4b5e-928e-9d8985ea179a 1464-5262 8224400 Dynamena disticha (Bosc, 1802) ( Figure 7I, J ) Material examined 3 colonies, polyp, without gonophores; Punta Diablo , La Paz Bay , Baja California Sur , 24.316°, 110.340°W; depth 0–1 m ; 7 May 2017 ; on rock; ECO-CH-Z 11753 . – Several colonies, polyp, without gonophores; Punta Los Muertos, Baja California Sur , 24.248°N , 110.150°W ; depth 1–2 m ; 20 July 2018 ; on the alga Gracilaria sp .; ECO-CH-Z 11767 . – 1 colony, polyp, without gonophores; El Califín , La Paz Bay , Baja California Sur , 24.268°N , 110.616°W ; depth 0.5–2 m ; 25 May 2018 ; on the alga Sargassum horridum ; ECO-CH-Z 11782 . – Several colonies, polyp, without gonophores; El Califín , La Paz Bay , Baja California Sur , 24.268°N , 110.616°W ; depth 0.5–2 m ; 4 September 2018 ; on the alga Codium brandegeei ; ECO-CH-Z 11781 . – 1 colony, polyp, without gonophores; Agua de Yepiz , La Paz Bay , Baja California Sur , 24.288°N , 110.630°W ; depth 0–1 m ; 24 June 2018 ; on the alga Sargassum sp .; ECO-CH-Z 11786 . Identification (after Calder 1991 ; Miranda et al. 2011 ) Colonies erect; hydrocaulus monosiphonic, unbranched, divided into internodes by oblique nodes. Basal athecate separated from the thecate internodes by an oblique node; thecate internodes with 1–3 pairs of opposite hydrothecae. Hydrothecae only contiguous in front of internodes, separated across back, parts of adcauline wall nearly straight and parallel to internodes, free part convex, curved outwards; abcauline wall concave except for basal part. Hydrothecal margin with two large rounded lateral cusps and a smaller median adcauline cusp. Operculum formed by two valves, a large abcauline and a smaller adcauline. Distribution Previously recorded on the west coast of the Gulf of California in Baja California and Baja California Sur ( Fraser 1938b , 1948 ; Mendoza-Becerril et al . 2020 ) and for the rest of the gulf in Nayarit ( Fraser 1948 ). In the MP, it has been recorded off the coasts of Baja California , Baja California Sur , Guerrero , and Oaxaca ( Fraser 1938a , 1938c , 1948 ). Remarks A colony of the labelled sample PD_6 exhibited second-order branching, a morphological variation previously recorded for D. disticha ( Calder 1991 ) .