Fine structure of the statocyst sensilla of the mysid shrimp Neomysis integer (Leach, 1814) (Crustacea, Mysidacea)

Abstract

The fine structure of the statocyst sensilla of Neomysis integer was investigated. The statocyst contains about 35 sensilla, which are composed of two bipolar sensory cells, nine enveloping cells, and a seta. The sensory cells consist of an axon, a perikaryon, and a dendrite. The dendrite contains a proximal segment with a ciliary rootlet and at least one basal body, and a distal segment with a ciliary axoneme (9 × 2 + 0) at its base. The distal segment extends along the peripheral wall of the seta and is in close contact with the wall of the hair shaft. The enveloping cells surround the proximal and distal segments of the dendrite. The innermost enveloping cell contains a scolopale rod. It surrounds the receptor lymph cavity and secretes flocculent material into this cavity. From the tip of the cell a dendritic sheath, which encloses the distal segment of the dendrite, emerges. A peculiar feature of the second enveloping cell is the presence of a scolopale-like rod, which is more slender and less pronounced than in the first enveloping cell. The seta consists of three parts: a socket, a tubular midpart, and a gutter-like apical part, the tip of which penetrates into the statolith. The seta shows over its full length a bilaterally symmetrical axis that is coplanar with the plane in which the seta is bent toward the statolith. The structure of the seta and the position of the distal segments provide morphological evidence for directional sensitivity of the sensilla and for the magnitude of shear on the setal wall being an adequate stimulus.

Ultrastructure and physiology of the hooded sensillum, a bimodal chemo‐mechanosensillum of lobsters

“…Structural characteristics of dendrites also reflect the modality of chemosensory neurons innervating insect sensilla (Altner and Prillinger, 1980; Lee and Strausfeld, 1990; Shanbhag et al, 1999). Similarly, common structural features of mechanosensory dendrites have also been identified in crustaceans (Mellon, 1963; Takahata and Hisada, 1979; Crouau, 1982; Kouyama and Shimozawa, 1982; Altner et al, 1983; Schmidt and Gnatzy, 1984; Espeel, 1985; Schmidt, 1989; Hertwig et al, 1991; Cate and Roye, 1997) and insects (Thurm, 1964; Gaffal et al, 1975; Hansen, 1978; Altner and Prillinger, 1980; Barth, 1981). Thus, structural features can be good indicators of the modality of sensory neurons innervating arthropod sensilla.…”

Statoliths of the whelk Buccinum undatum: a novel age determination tool

“…In lieu of being able to directly use the shells or opercula to estimate age, an alternative age registering structure was sought; whelks contain an accretory hard structure called a statolith which is the focus of this paper. Statoparticles (such as statoliths) are structures that are integral to the nervous system of a diverse range of animal groups including the Polychaeta (Beesley et al 2000), Holothuroidea (Ehlers 1997), Crustacea (Espeel 1985) and several classes of the Mollusca e.g. the Bivalvia (Morton 1985), Gastropoda (Barroso et al 2005, Chatzinikolaou & Richardson 2007, Galante-Oliveira et al 2013 and Cephalopoda (Arkhipkin 2005).…”

Non-olfactory chemoreceptors in asymmetric setae activate antennular grooming behavior in the Caribbean spiny lobsterPanulirus argus

“…In all cuticular sensilla of decapod (and other) crustaceans in which a scolopale has been identified, it is always located below the socket (e.g. Schöne and Steinbrecht, 1968;Ball and Cowan, 1977;Altner et al, 1983;Espeel, 1985;Cate and Roye, 1997), allowing that displacement of the shaft within the socket acts as the adequate stimulus. Consequently this mode of stimulus transformation is believed to represent the general principle in mechanosensitive setae of crustaceans (Crouau, 1982), as well as other arthropods (Barth and Dechant, 2003).…”