A new species of Nesolinoceras Ashmead from the Dominican Republic is described and illustrated. A key to the species and a revised and expanded distribution map is presented. This is the third species recognized for the genus, and the first one confirmed to occur in high altitude (1100 m). When compared with the previously known species, a number of unique and shared features emerged, supporting a redefinition of the genus beyond that of Santos (2016): (1) the known inter-specific variability of 48% of the examined characters increased considerably, confirming their diagnostic value at the species-level, and (2) the stability of six features support them as additionally diagnostic for the genus: 2223 flagellomeres; mesoscutum subcircular, as long as wide; scuto-scutellar carina absent, axillary trough shallow, indistinct on scutellum; subalar ridge wide, somewhat ovoid, not keeled; crossvein 1cu-a arising basad of vein 1M+Cu by about 0.3 its length; and vein 2-M only slightly longer than vein 3-M. Furthermore, two important measurements for the diagnosis of Nesolinoceras now have new, expanded ranges: areolet 1.82.6 as long as pterostigma width, and areolet 0.71.0 as long as wide. The new taxon is readily recognizable by having the body mostly brown, fully infuscated wings, and the longest ovipositor of the species, among other diagnostic features. A new geographic record and in situ photo are also provided for N. laluzbrillante Santos.