Arthropods (Mar 2023)
Mechanoreceptors found on larval and juvenile stage of Squilla empusa Say 1818 (Stomatopoda: Squilloidea)
Abstract
The mechanoreceptors found on the larval stages and juvenile stage of squilloid stomatopods are investigated using photomicrographs and scanning electron micrographs. The frequency which may be detected by a sensillum is related to its length and the thickness of the boundary layer. Early stage alima larva, the larval form of the Squillidae, have paired peg sensilla on the distal margins of the annuli of the antennule flagella. These sensilla are potentially capable of detecting nearfield sound energy at frequencies ≥ 2.0 kHz. In the later alima larval stages, the peg sensilla are present in both paired and triple sets. The triple sets of sensilla are potentially capable detecting nearfield sound energy at frequencies ≤ 0.02 kHz. In both early and late alima larva the distal margin of each antennule flagella annuli is found to have a tactile sensilla. In the late alima larval stage, there are ten sensilla at the distal end of the coxa of the antennules. The scale of the antenna is armed with numerous peg sensilla potentially capable of detecting nearfield sound energy at frequencies greater than ≤ 0.02 kHz. Peg sensilla are also found on the posterior margins of the walking legs. The flagella of the juvenile stage of Squilla empusa Say have a tuft of sensilla on the distal margins of each annulus. Six sensilla are found on the walking legs of the juvenile stage. A tympanum-like structure similar in shape and location to that reported in the literature on the stomatopod Ostratosquilla is found on the coxa of the juvenile stage of Squilla empusa Say.
