23 Mexican hydrological basins.

1 Oases of Baja California Sur; 2 Río Yaqui; 3 rivers near Chamela, Jalisco; 4 Río Santiago; 5 Río Armería - Ayuquila; 6 Río Balsas; 7 bodies of water in Guerrero State; 8 Río Atoyac-Verde; 9 Río Tehuantepec; 10 Rivers along the south Pacific coast of Chiapas; 11 Río Bravo; 12 Río Lerma; 13 bodies of water of Valley of Cuatro Ciénegas; 14 Río Mezquital, Río Nazas and springs of Durango state; 15 Río San Fernando, Río Soto La Marina and other bodies of water in Tamaulipas; 16 Río Pánuco; 17 Río Tuxpan; 18 Río La Antigua; 19 bodies of water of Los Chimalapas; 20 Río Papagayo; 21 bodies of water in coastal plain of Tabasco; 22 basins of Río Usumacinta and Río Grijalva, Chiapas; 23 bodies of water of the Yucatán Peninsula. Along with their four-letter code (abbr), geographical coordinates and total number of helminth species collected.