Small (L to 15 mm), subcircular, inflated. Colour white, yellow or orange. Waxy appearance. Sculpture of strong diverging radial ribs, broader and more widely spaced to the anterior and posterior. Ribs crossed by fine, closely spaced, commarginal lamellae which curve over ribs producing a roughly scabrous appearance. Central parts of shell generally without ribs. Lunule large, broadly lanceolate, smooth. Ligament internal, obliquely inset. Hinge: RV with single large cardinal tooth and short anterior and posterior lateral teeth, LV with two cardinal teeth, lateral teeth consisting of small sockets. Anterior adductor scar narrow, elongate, detached from pallial line for ca. half of length. Pallial line irregularly lobate, or slightly divided. Inner shell margin coarsely crenulate to anterior and posterior.

Rugalucina angela shows variation in shell morphology between various localities around the Arabian Peninsula and Red Sea. For example, shells from the Arabian Gulf are usually smaller, while those from the northern Red Sea as on Gulf of Suez shores are generally larger, and the marginal crenulations stronger. We regard these differences as ecophenotypic probably associated with the extreme environmental conditions such as the very high salinities experienced in the southern Arabian Gulf, usually more than 40 psu but in shallow lagoons as high as 52—55 psu (Price 1982) and approximately 40-46 psu at Safaga in the northern Red Sea (Zuschin and Oliver 2003) and probably higher for the habitats occupied by Rugalucina.
Rugalucina angela is closely similar in shell morphology to R. vietnamica and R. munda. The differences are subtle; externally they share diverging radial ribs that are stronger to anterior and posterior, and the fine commarginal lamellae. Rugalucina angela has a shorter anterior dorsal area, larger hinge plate and teeth, and a slightly more divergent anterior adductor scar. Rugalucina vietnamica is higher, with a longer anterior dorsal area. Rugalucina munda is similar but the radial sculpture is much less pronounced with finer margin denticulations and subdued commarginal sculpture.

Type locality. Gwadur, Pakistan, 8 fathoms (15m).
Distribution. Red Sea: Great Bitter Lake (Hoffman et al. 2006), Suez Canal, El Ballah (NHMUK 1950.11.10.1), Suez (NHMUK 1968.5.29.2), Safaga, Don-gonab Bay (NHMUK), Oreste Point, Yemen (Dekker colln), Aden (NHMUK 1963340). Arabian Gulf: Kuwait (NHMUK), Tarut Bay, Qatar (NHMUK), Abu Dhabi (NHMUK), Ras al Khaimah (NHMUK). Arabian Sea: Khor Kalba, Sharjah (NHMUK), Karachi, dredged (NHMUK 1953.1.30.85). Oman: Masirah Island (NHMUK). Indian Ocean: South India: Chennai (Madras) (NHMUK 1953.1.30.169-73), Krusadai Island (NHMUK 1953.1.30.110), Kundugal Point, Krusadai Island (NHMUK1953.1.30.175-181), Tuticorin (NHMUK 1953.1.30.99-101). Sri Lanka: Trincomalee (NHMUK 1910.9.28.175-178). Rugalucina angela (as Pillucina vietnamica) is recorded as an invasive species off Israel in the eastern Mediterranean (Steger et al. 2018).