Diagnosis: Chiloglanis longibarbis is distinguished from all other West African congeners, with the exception of C. waterloti, in having eight or fewer mandibular teeth in the functional row; it is distinguished from C. waterloti in having longer maxillary and mandibular barbels (Ref. 116018).
Description: A moderate-sized Chiloglanis; 41.4 mm maximum standard length observed; body dorsally depressed anteriorly; laterally compressed posteriorly; pre-dorsal convex; sloping ventrally towards orbit; pre-orbital convex; post-dorsal body sloping ventrally towards caudal fin; pre-anal profile convex; post-anal horizontal towards caudal fin (Ref. 116018). Small unculiferous tubercles scattered across body; higher concentrations on head and dorsum; lateral line complete; arising from level of orbit and sloping ventrally to midlateral along the side of body; urogenital papillae reduced and separated from anus by shallow invagination in females (Ref. 116018). Head depressed; gill membranes broadly united; gill openings restricted; opening slightly dorsal of pectoral-fin origin to lower margin of orbit; occipital-nuchal shield covered and visible through skin; eyes moderate; horizontal axis longest; without free margins; anterior and posterior nares positioned mid-snout length; posterior nares set slightly farther apart than anterior nares; nares with raised rims; posterior nares with elongated anterior flaps (Ref. 116018). Mouth inferior, upper and lower lips united to form oral disc; oral disc moderate in size, its width 18.7-21.2% of standard length; slightly longer than wide and covered in papillae (Ref. 116018). Barbels in three pairs; maxillary barbels originating from posterolateral region of the disc; unbranched and long, 38.2-44.4% of head length; lateral and medial mandibular barbels long; positioned on both sides of prominent midline cleft on posterior margin of disc; lateral barbels, 20.6-28.1% of head length, usually less than twice the length of median barbels (Ref. 116018). Primary premaxillary teeth "S"-shaped; exposed brown tips; 32-64 in three scattered rows on two ovoid tooth pads; secondary premaxillary teeth scattered on posterior surface of premaxillae; tertiary premaxillary teeth small and needle-like; in a row near midline on dorsal edge of toothplate; mandibular teeth in 1-2 rows; "S"-shaped and crowded near midline; functional, anterior, row usually contains eight brown-tipped teeth (Ref. 116018). Dorsal-fin origin just posterior to anterior third of body; dorsal fin with small spinelet, spine, and five rays; dorsal spine relatively long, 17.0-20.7% of standard length; anterior margin mostly smotth; posterior margin of spine with three small notches distally; adipose fin moderate in length, 19.2-27.0% of standard length; origin anterior to anal-fin origin; margin convex with small notch at terminus; caudal fin forked with rounded lobes; lower lobe longer than upper lobe; count i,7,8,i; anal-fin origin posterior to origin of adipose fin; margin convex; count iii,6; pelvic-fin origin at vertical between dorsal and adipose fin; margins convex; reaching anal-fin origin; count i,6; pectoral fin with slightly curved smooth spine; relatively long, 20.8-23.6% of standard length; count I,8-9 (Ref. 116018). Postcleithral process short and bluntly pointed in females (Ref. 116018).
Colouration: In dorsal view, body medium brown; mottling of yellow-buff to light brown along dorsum and side; head medium brown; areas of light brown at origin of dorsal fin and origin and terminus of adipose fin, melanophores scattered throughout; in lateral view, body yellow-buff with overlying medium browns; some light areas observed dorsally extend beyond the midline, dark areas below the midline, extending to near pelvic and anal-fin origins, and around the caudal peduncle; small dark brown melanophores scattered across sides; easily observed below the midline; ventral surface cream-buff with scattered melanophores; more numerous near pelvic and pectoral-fin origins; oral disc and barbels cream (Ref. 116018). Pectoral and dorsal spines and rays translucent to cream; melanophores at origin of dorsal and pectoral fins; scattered melanophores create a broad bar at mid-length; pelvic fins cream; bar of melanophores at mid-length; adipose fin translucent to cream; small area of brown near base at midlength; anal fin translucent to cream; melanophores at base and mid-length; caudal fin translucent to cream; brown areas near base and mid-length of upper and lower lobes (Ref. 116018).