Differential diagnosis. Sensiava is a calanoid copepod belonging to Diaixidae as defined by Markhaseva et al. (2014). The genus is distinguished from other diaixids by the following general characters: i) males right antennule of 23 segments with geniculation; ii) in females and males distalmost terminal seta of maxillule praecoxal arthrite curved at the apex; iii) in males 2 terminal endopodal setae of maxilliped are very long, more than 1.6 times longer than basis; iv) male P 5 of complex structure, left leg biramous, exopod 2 -segmented.
Additional combination of characters, that define the genus among diaixids are: i) males antennule ancestral segments X–XI fused (shared with Cenognatha, Neoscolecithrix and Xancithrix); ii) antenna endopod segment 1 with 1 seta (shared with Diaixis (?) and some species of Byrathis); iii) antenna exopod setal formula: 0,0- 0- 1,1, 1,1, 1,1, 3 (shared with Xantharus), or 0,0- 1 -1,1,1,1,1,1,3 (shared with Grievella); iv) in females maxillule coxal endite with 4 (shared with Falsilandrumius), or 5 setae (shared with Xancithrix and Thoxancalanus); v) maxilla endite setal formula is: 5 setae (or 4 plus attenuation), 3, 3, 3, and 4 setae; vi) setae of the maxilla basal endites and enditic-like lobe of endopod are similar in shape and size, curved or curled distally; vii) proximal basal maxilla endite with 1 seta worm-like (shares with Ranthaxus); viii) maxilla endopod setal formula: 3 w+ 5 br (shared with some species of Byrathis, Diaixis, Cenognatha, some species of Xantharus), or 3 w+ 5 br+ 1 sc (shared with Paraxantharus, Xancithrix, some species of Xantharus, and Thoxancalanus); ix) female P 5 uniramous, 3 - segmented, terminal segment with 4 spines, medial spine is the longest; x) male P 5 right and left coxa and basis of the nearly same length (shared with Byrathis, Paraxantharus and Xantharus).