CHAPTER 49 SUBCLASS HOPLOCARIDA CALMAN, 1904: ORDER STOMATOPODA LATREILLE, 18171) BY FREDERICK R. SCHRAM, SHANE T. AHYONG, SHEILA N. PATEK, PATRICK A. GREEN, MICHAEL V. ROSARIO, MICHAEL J. BOK, THOMAS W. CRONIN, KRISTINA S. MEAD VETTER, ROY L. CALDWELL, GERHARD SCHOLTZ, KATHRYN D. FELLER AND PERE ABELLÓ Contents. – Introduction and definition – General remarks – Diagnoses. External morphology – Body regions – Appendages – Sexual dimorphism. Internal morphology – Central nervous system – Digestive system – Reproductive system – Respiratory system – Circulatory system – Endocrine system – Excretory system – Muscular system. Sense organs and sensory systems –Vision–Non- visual senses and structures – Summary and conclusions. Embryonic development and larvae – Embryonic development – Larvae. Ecology and ethology – Introduction – Ecological patterns – Anatomical and physiological patterns – Behavioral patterns – Conclusions. Economic importance. Biogeography – General distribution patterns – Distribution patterns within the superfamilies. Fossil record – Aeschronectida – Stomatopoda. Phylogeny. Systematics. Acknowledgements. Appendix. Bibliography. INTRODUCTION AND DEFINITION General remarks The mantis shrimp are fascinating crustaceans. They intrigue us because of their bright colors, their bizarre appendages, to say nothing of their impressive visual, olfactory, and acoustic abilities. For those willing to look beyond these characteristics, truly amazing features await notice. Their capacities to manipulate the environment and respond in subtle 1) Not published previously in the French edition; original chapter created April 2013 by the team of authors as mentioned; final additions May 2013. © Koninklijke Brill NV, Leiden, 2013 Crustacea 4A (49): 179-355 180 F. R. SCHRAM ET AL. ways to their surroundings, and the speed and intensity by which they communicate with each other mark them amongst the “intelligentsia” of crustaceans. Many aspects of the basic biology of the almost 500 species of living Stomatopoda are relatively well investigated. This is especially true in regard to the visual physiology, their behavior, their general anatomy, and their larval development. Nevertheless, other aspects, rather astonishingly, have rarely been studied at any great depth, such as their embryonic development. Stomatopods serve as laboratory animals, and they have important economic roles to play not only as top predators of marine food chains, but also as food themselves. Furthermore, Hoplocarida play a central role in our understanding of malacostracan evolution and phylogeny. While the present day mantis shrimp share a distinct, yet relatively uniform Bauplan, we now can see within the deep history encompassed by all the hoplocaridans a great disparity of forms. Few other groups present us with such an array of “missing links” that lend insight into how the unipeltate stomatopods evolved. Diagnoses Hoplocarida are Eumalacostraca with a pleon better developed than the cephalotho- rax. The eyes generally are stalked and lobate, the antennules bear three flagella, the anten- nal scale (scaphocerite) has two articles (the basal-most generally small), the thoracopods have 3-segment protopods (pre-coxa, coxa, and basis) and 4-segment endopods (or inner branches), and the dendrobranchiate gills arise from the bases of the pleopods. Stomatopoda are hoplocaridans that exhibit a reduced carapace (with the exception of some of the Paleozoic stem groups), utilize a kinetic cephalon, possess sub-tagmata within the cephalothorax, display the anterior thoracopods specialized in varying degrees as subchelate limbs, and elaborately develop the tail fan. EXTERNAL MORPHOLOGY [SHANE T. AHYONG] General habitus Stomatopods have an elongate, dorsoventrally depressed body that follows the general malacostracan pattern of 19 somites in addition to the ophthalmic/protocerebral region (which bears the eyes, Scholtz & Edgecombe, 2006) (figs. 49.1-49.4). The body is typically regarded as having three functional regions or tagmata: cephalothorax, thorax, and pleon. Although further subdivision of the anterior tagma may better reflect functional divisions, the current system is followed here for convenience. All stomatopods have the same fundamental body plan, but the body shape in terms of cross-section differs among superfamilies. Gonodactyloids and parasquilloids have sub- cylindrical bodies, as in the stem-lineage stomatopods, Pseudosculdidae. Squilloids and bathysquilloids have dorsoventrally depressed bodies, and lysiosquilloids, erythrosquil- loids and eurysquilloids, have the distinctly flattened bodies..