Description
Dorsal spines (total): 7; Dorsal soft rays (total): 9-10 (usually: 10); Anal spines: 1; Anal soft rays: 9; Pectoral fin rays: 16-18 (usually: 17); Longitudinal scale count: anterior cycloid = 10-20 - posterior ctenoid: 29-40; Total longitudinal scale count: 45-57; Transverse scale count: 17-19 (usually: 18); Gill rakers on outer face of first arch: 1-3 + 1 + 9-13, total: 12 or 15 or 17; Gill rakers on outer face of second arch: 3 + 12 or 3 + 1 + 14 or 4 + 14 or 5 + 13; Segmented caudal fin rays: 8/8 or 9/8; Branched caudal fin rays: 6/7 or 7/6 or 7/7 or 8/7; Vertebrae 10 + 16, anterior zygapophyses prominent on vertebrae: 1–10. Head rounded in cross section, head length: 29.3–33.7% SL; Head width at preopercular margin: 18.7–21.4% SL. Snout rounded in dorsal view, steeply oblique (slightly convex) in side view: 6.0–7.2% SL. Eye relatively small and elevated, no groove behind eye, eye slightly less than snout length: 5.7–7.6% SL. Anterior nostril at end of short tube, just above upper margin of upper lip, base of nasal tube more than one nostril diameter above upper lip, lower rim of tube almost in contact with upper lip; Posterior nostril a large pore anterior to lower part of eye, midway between anterior nostril and eye and two nostril diameters from eye and two to three nostril diameters from anterior nostril. Preoperculum short: 8.9–9.3% SL, horizontal distance from end of eye to upper posterior preopercular margin subequal to distance from snout to middle of eye. Postorbital long: 16.8–18.1% SL, slightly shorter than distance from tip of snout to posterior preopercular margin. Body moderately robust, depth at anal-fin origin: 19.3–21.9% SL. Upper jaw relatively short: 13.0–14.6% SL, reaching to below a point between just before posterior margin of eye and just in front of posterior margin of eye. Body covered with cycloid scales anteriorly and with ctenoid scales posteriorly, ctenoid in wedge to below fifth to sixth first-dorsal-fin spine and dorsally from second dorsal-fin origin (a few scattered cycloid scales at base of second dorsal fin in some specimens) and ventrally from posterior end of anal fin, except a thin line of cycloid scales at base of anal fin. Sides of head naked, predorsal midline and sides scaled to a point just before to just behind posterior preopercular margin. Pectoral-fin base usually with embedded scales centrally or ventrally, rarely naked; Prepelvic area usually scaled, except for a naked patch anteriorly (fully naked in juveniles). Belly fully covered with cycloid scales. First dorsal fin low, pointed, with one or two filamentous spines in males and with a rounded margin in females, second and third dorsal-fin spines longest, second spine length: 22.6–31.2% SL in males and 20.2–25.2% SL in females; Adpressed length of first dorsal fin: 28–34.5% SL in males, reaching to above first to fifth segmented dorsal-fin ray, and 22.4–27.9% SL in females, reaching to above a point between second-dorsal-fin spine and second segmented dorsal-fin ray, second dorsal-fin origin just behind a vertical line from pelvic-fin insertion. Pectoral fin with rounded margin, reaching to above or behind pelvic-fin tip, to or just behind anus, length: 25.1–31.2% SL. Pelvic disc large, reaching to or slightly beyond anus in male or slightly before anus in female, pelvic fin length: 24.6–30.7 SL. Caudal fin with rounded posterior margin, central rays longest, length: 27.5–32.3% SL. Max. length: 12 cm TL. Depth range: 0 - 15 m, usually: 0 - 10 m.

Color
Head and body mostly brownish with overlay of blue spots posteriorly and dorsal, anal, and pelvic fins with distinctive patterns of brownish spots, stripes, and bars, also with a broad brown band crossing head above preoperculum and a similar band above operculum, containing a dark brown short crossbar, or elongate spot, just before first dorsal-fin origin; Interspaces light gray to white; Papillae on sides not distinctive in coloration. Ventral surface of head light brown, with four dark-brown crossbars, last two bands extending dorsally (vertical or sloping posteriorly dorsally) onto lower operculum and preoperculum, breaking up into scattered mottling; A rounded to horizontally elongate spot (ocellated in some specimens) below anterior part of first dorsal fin on midline of body. Sides of belly with four or five thin darkbrown bands with white interspaces about equal in width to dark bands, posteriormost interspace continuous with interspace extending upward to near anterior part of first dorsal fin. First dorsal fin translucent, with brown pigment before and after spines and with scattered brown mottling posteriorly. Pelvic disc brown, with four to six dark-brown crossbars on central rays, outer rays of disc dark brown with two or three white lines along rays.

Etymology
Cryptocentrus: from Greek, kryptos = hidden + from Greek, kentron = sting. Referring to a concealed point or projection on preopercle.
strigilliceps: from Latin, strigilis -is = Kind of sinuous grooves which serve as ornament to a certain number of ancient sarcophagi + from Latin suffix, -ceps = headed. Referring to the head papillae prominent, form distinct ridges.
Original description: Mars strigilliceps Jordan & Seale, 1906 - Type locality: Apia, Upolu Island, Samoa.

Distribution
Red Sea, Indo-West Pacific: East Africa, Seychelles and Madagascar east to Philippines, Kiribati, Tonga and Samoa, north to Ryukyu Islands (Japan), south to Queensland (Australia) and New Caledonia.

Biology
Occurs in silty bottoms of lagoon or coastal reefs. Common near areas with terrestrial runoff. Lives with alpheid shrimps.

Similar species
Cryptocentrus altipinna (Hoese, 2019) - Reported from Indian Ocean: Tanzania, Sri Lanka and the Andaman Sea off Thailand.