The Unique Dorsal Brood Pouch of Thermosbaenacea (Crustacea, Malacostraca) and Description of an Advanced Developmental Stage of Tulumella unidens from the Yucatan Peninsula (Mexico), with a Discussion of Mouth Part Homologies to Other Malacostraca

摘要: The Thermosbaenacea, a small taxon of crustaceans inhabiting subterranean waters, are unique among malacostracans as they brood their offspring dorsally under the carapace. This habit is evolutionary interest but last detailed report on thermosbaenacean development more than 40 years old. Here we provide new observations an ovigerous female Tulumella unidens with advanced developmental stages in its chamber collected from anchialine cave at Yucatan Peninsula, which only third Thermosbaenacea and first for genus Tulumella. Significant wider crustacean context, discuss hitherto unexplored lobate structures inside originating (maxilliped) second thoracic segments, most likely modified epipods, perhaps serving gills. At posterior margin carapace rows large spines preventing developing falling out. external morphology described much detail, providing information e.g., formation early limb morphology. Among unknown provided by this study presence embryonic dorsal organ rudimentary ‘naupliar processes’ antennae. Since hypotheses (and malacostracan peracaridan) relationship rest morphology, use bud to better establish homologies those other crustaceans, necessary basis future based phylogenetic considerations.