Hoplocarida

Article By:

McLaughlin, Patsy A. Shannon Point Marine Center, Western Washington University, Anacortes, Washington.

Last reviewed:January 2020

DOI:https://doi.org/10.1036/1097-8542.322700

A subclass of Crustacea, including a single extant order, Stomatopoda, commonly known as mantis shrimps. The Hoplocarida was formerly included as a taxon within the Eumalacostraca, and disagreement regarding its independent origin still persists. The controversy centers on the question of whether those elements of the eumalacostracan caridoid facies observed in hoplocarids represent examples of homology or convergence. Investigations of fossil (Paleostomatopoda) and Recent Stomatopoda suggest that a distinct set of morphological features, sometimes referred to as a hoploid morphotype (see illustration), clearly delineate the Hoplocarida from the Eumalacostraca. Those characters include cephalic kinesis, triflagellate antennules, thoracopods with trisegmented protopods, five pairs of subchelate thoracic appendages (“maxillipeds”), abdominal gills, and an elongate tubular heart that extends the length of the body and has segmentally arranged ostia and arteries. Morphological aspects of feeding observed in modern-day species, as well as features of the digestive system and abdominal musculature, tend to support the hypothesis of a distinct origin. See also: Crustacea; Eumalacostraca; Stomatopoda

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