Animalia Biodiversity Taxonomy Demospongiae Porifera Gulf of Mexico Campeche Bank Haplosclerida Chordata Marine Biology Mexico Yucatan fishes Actinopterygii Coral Hadziidae Mexican Atlantic Perciformes reef species richness Caribbean SEM Serranidae amphipods decapods groundwater isopods mysids sinkholes stygiomysids thermosbaenaceans Yucatan Peninsula cenote description endemic mitochondrial marker morphology sinkhole subterranean Arthropoda Malacostraca Poecilosclerida Ecology Ecosystem Ecology Haemulidae Marine Biodiversity Marine Ecology Mollusca Marine Environment coral reef marine reserves mollusks Agelasida Chitonida Halichondrida Niphatidae Polyplacophora Species diversity