Pseudolaguvia nubila differs from congeners except for P. austrina, P. kapuri, P. spicula, P. virgulata and P. viriosa in having a deeper caudal peduncle (9.1–11.1% SL vs. 5.0–9.0) and a combination of the following characters: head width 19.7–21.0% SL, dorsal-spine length 16.4–19.3% SL, pectoral-spine length 18.1– 22.0% SL, pelvic-fin length 15.8–18.5% SL, and body depth at anus 13.9–17.1% SL. It is distinguished from P. austrina in having a mottled brown body with yellowish bands (vs. uniform pale brown body), a weakly projecting snout in which the premaxillary teeth are barely exposed (vs. a strongly projecting snout in which the premaxillary teeth are almost entirely exposed) when the mouth is closed, a larger eye (10.8–14.0% HL vs. 4.4–8.1), fewer serrations on the anterior edge of the pectoral spine (7–8 vs. 17–19), a shorter dorsal to adipose distance (13.1– 16.8% SL vs. 29.5–32.7) and longer caudal peduncle (15.7–20.2% SL vs. 8.8–14.7); and from P. kapuri in having a smooth (vs. serrated) anterior edge of the dorsal spine, a shorter adipose-fin base (14.2–15.9% SL vs. 17.1–18.9), and narrower head (19.7–21.7% SL vs. 23.4–24.0), and from P. spicula in having longer dorsal- (16.4–19.3% SL vs. 11.6–14.3) and pectoral-fin (18.1–22.0% SL vs. 15.7–17.4) spines and fewer serrations (7–8 vs. 9–15) on the anterior edge of the pectoral spine. Pseudolaguvia nubila differs from P. virgulata in having shorter dorsal- (16.4– 19.3% SL vs. 21.5–24.0) and pectoral-fin (18.1–22.0% SL vs. 28.5–29.1) spines, a smooth (vs. serrated) anterior edge of the dorsal-fin spine, the presence of pale vertical bands (vs. pale longitudinal stripes) on the flanks and the absence (vs. presence) of a pale Y-shaped marking on the dorsal surface of the head and supraoccipital process, and from P. viriosa in having shorter dorsal- (16.4–19.3% SL vs. 23.4–29.0) and pectoral-fin (18.1–22.0% SL vs. 26.9– 32.9) spines. (Ref. 93571).