Echiniscus spinulosus (McInnes, 1994)

Gąsiorek, Piotr & Sørensen, Martin V., 2025, Too many spines, or an integrative foundation of the Echiniscus spinulosus morphogroup (Heterotardigrada: Echiniscidae), Organisms Diversity & Evolution 25 (1), pp. 223-247 : 235

The Echiniscus spinulosus morphogroup

For the present, most spp. are well diagnosed ( Table 6), which means that the taxonomy of the morphogroup is in relatively good condition. Given the uncovered nuances in dorsal plate sculpturing, we can distinguish two main subtypes within the spinulosus sculpture: (I) with minute intracuticular pillars still present, identifiable in a deep focus in a light microscope (only E. spinulosus and E. belloporus , Figs. 4B , 9G ); (II) without intracuticular pillars, which probably merged into uniform cuticular matrix (all remaining spp.). The subtype II sometimes exhibits other epicuticular elements, like granules or striae ( E. marcusi , E. minutus ). This datum nicely corresponds with the phylogeny, which pinpoints that E. spinulosus and E. belloporus do not belong to the same evolutionary lineage as other spp. of the spinulosus morphotype (see fig. 2 in Gąsiorek and Michalczyk (2024) for the latest update).

Figures

Fig. 4 Sculpturing in E. spiniger (PCM): A scapular plate, focus on pores, B scapular plate, focus on intracuticular pillars, C caudal (terminal) plate, focus on pores (empty black arrowhead indicates a dark

Fig. 9 Dorsal armour and the morphology of appendages in E. belloporus (all but F, G SEM, F, G PCM): A habitus in dorsal view, B median plate 1 and the first paired segmental plate, C median plate 2 and the second paired segmental plate, D pores in the caudal plate in close-up, E median plate 3 and caudal (terminal) plate, F plates in dorsolateral view, G the first paired segmental plate, focus on intracuticular pillars. Scale bars in μm