Shell narrow, up to 94.5 mm in length with small, rounded protoconch of 1.5 whorls (Fig. 23G) and weakly convex teleoconch whorls. Axial sculpture of last teleoconch whorl consisting of 3 narrow, high varices with abapical varical flange extending on the siphonal canal. Other axial sculpture of 3-5 narrow, nodose, intervarical ridges. Spiral sculpture of narrow, high, primary cords, narrower secondary cords and few tertiary cords. Spiral sculpture of subsutural ramp of last whorl with adis, IP, abis followed by P1, s1, P2, s2, P3, t, s3, t, P4, s4, P5, P6, s6, ADP, MPm and ABP on convex part of shell and siphonal canal.
Aperture ovate. Columellar lip smooth. Outer lip erect, with split, narrow, elongate denticles within. Siphonal canal moderately long, ventrally narrowly open, weakly dorsally bent, with 3 broad, webbed, open spines, ADP, MP, and ABP First teleoconch whorls pink or pale orange, teleoconch whorls light brown with 2 darker brown bands on last whorl, more obvious on axial varices and brown blotches on and between ridges.

Naquetia fosteri has long been confused with N. barclayi, largely due to the shell variability in Muricidae. Nevertheless, it differs from both species N. barclayi and N. annandalei by its narrower and elongate shell, by its numerous intervarical ridges, and by its paucispiral protoconch consisting of 1.5 whorls compared to the conical and multispiral protoconch in both N. barclayi and N. annandalei.

Type locality. Red Sea, Gulf of Aqaba, off Eilat.
Distribution. Indo-W. Pac. (I). Red Sea, Northern end of the Gulf of Aqaba.