The morphology, arrangement, and ultrastructure of a new type of microtrich sensilla in marine isopods (Crustacea, Isopoda)

Abstract

Background: Microtrich sensilla are a special type of cuticular structures found on the external surface of amphipod and isopod crustaceans. These cuticular microstructures, being important for systematic and phylogenetic studies, display a wide diversity of shapes and distribution among different taxa. Here, the microstructure of the cuticular surface of 11 marine isopod species was investigated by scanning electron microscopy. Results: On the dorsal and lateral sides of all the taxa examined, only one distinct type of microtrich sensillum was found in the regular rows. While this structure is very similar to that of the Ib microtrich type (sensu Crustaceana 13:100-106, 1988), however, it is distinct from the previous type, in which it has an elongate cuticular ring or specialized collar encircling the shaft base of the microtrichs. The findings indicate that different taxa of marine isopods may show a new type of microtrich sensilla differing in morphology and arrangement. Conclusions: The findings indicate that different taxa of marine isopods may show a new type of microtrich sensilla differing in morphology and arrangement.

The First Insight into the Patterns of Size and Shape Variation of a Microcerberid Isopod

“…Sensilla [45,46] refer to minute cuticular sensory receptor organs covering a vast area of the crustacean body [47]. Due to their variability in size, shape, number, and position, many studies have investigated their taxonomic importance in various crustacean taxa [48][49][50][51][52][53][54]. The pleon's anatomical points along each pleonite and pleotelson boundary are used to estimate segment length ratio changes, which is considered important in the taxonomy of isopods [33,34].…”