Sphinctozoans are the most abundant hypercalcified sponge group within the Late Triassic shallow water carbonates of the Tethyan realm. They have been described from numerous localities of western Tethys (European region) and northern Tethys (Pamir Mountains), but relatively little is known about Triassic sphinctozoans and hypercalcified sponges from the southern and eastern areas of the Tethyan realm (Senowbari-Daryan and García-Bellido, 2002). The discovery of new, well-preserved sphinctozoan material is an important addition to knowledge of the sponge fauna of the region. Bernecker (1996) and Senowbari-Daryan et al. (1999) reported on some Late Triassic sphinctozoans and other hypercalcified sponges from Oman in the Arabian Peninsula, but no other data are available from the south-central portion of Tethys along the north margin of Gondwana. Elliott (1963) described a small, chambered organism from the Paleocene of northern Iraq as a sphinctozoan sponge (Calymenospongia kurdistanens), but this has a maximum diameter of 0.72 mm and appears to be an agglutinated foraminifer, not a sponge (Senowbari-Daryan and García-Bellido, 2002). Hajarispongia osmani n. gen. and sp., the first sphinctozoan sponge reported from the United Arab Emirates, is a multibranched sphinctozoan with large areas of exterior wall surface exposed and positioned so that it can be longitudinally sectioned along three branches, cut in oriented sections, and examined externally as well as internally. The combination of characters present in this sponge shows the need for describing an additional genus of sphinctozoan sponges and revising sponges previously placed in the genus Colospongia (Laube, 1865). The classification of hypercalcified sponges proposed by Finks and Rigby (2004) is used for description of sponges in this paper. Morphological terms conform to the terminology presented in Kaesler (2004) and illustrated by Rigby and Potter (1986), of which the following terms are of special importance in the description and study of Hajarispongia: 1) cribribulla—inward facing, blisterlike sieve at the inner end of an exaulos; 2) cribripore—small pores in sievelike cribribulla; and, 3) exaulos—spoutlike tube in sponge wall.