Daghanirhynchia angulocostata Cooper, 1989

Feldman, Howard R., Schemm-Gregory, Mena, Ahmad, Fayez & Wilson, Mark A., 2012, Jurassic rhynchonellide brachiopods from the Jordan Valley, Acta Palaeontologica Polonica 57 (1), pp. 191-204 : 199

Daghanirhynchia angulocostata Cooper, 1989

Fig. 3D.

1989 Daghanirhynchia angulocostata sp. nov.; Cooper 1989: 26–28, pl. 6: 1–19, pl. 7: 44–53, pl. 11: 16–21, figs. 13, 14.

Material.—Two articulated specimens: AMNH FI− 72395, AMNH FI− 72396, bed S−7, Mughanniyya Formation (Callovian, upper Middle Jurassic), Tel el Dhahab section, Jordan.

Description.—Shells large ( Table 4), outline widely triangular with maximum width anterior to midlength. Anterior commissure strongly uniplicate; costae coarse and subangular in cross section, 14–15 in number; ventral beak narrow, suberect; ventral interarea low. Foramen medium to large, longitudinally oval to suboval. Deltidial plates disjunct.

Ventral valve almost flat in lateral view, umbonal region moderately swollen. Sulcus originates just posterior to midlength and deepens anteriorly with 3–4 costae. Linguiform extension moderate with narrow, slightly convex flanks adjacent to sulcus with 6–7 costae.

Dorsal valve moderately convex in lateral profile, moderately to gently domed in anterior view; fold originates just posterior to midvalve but in some shells at midvalve, elevating slightly with 4 costae, 6 costae on dorsal flank.

The internal structures of the shells are unknown due to a lack of sufficient material for serial sectioning.

Discussion.—The Jordanian specimens compare favourably with Cooper’s (1989) shells in that they are large and widely triangular with maximum width anterior to midlength. Muir−Wood’s (1935) description of the genus includes the presence of fine radial striae as a feature of the genus. Cooper (1989) did not observe these features on his shells from Saudi Arabia and found none on the specimens in the USNM collections from the type locality of D. daghaniensis Muir−Wood, 1935 ( USNM 75665, 75666). The Jordanian shells are also lacking this feature as well as the thickened deltidial plates observed by Cooper (1989) in his Saudi Arabian shells. Stratigraphic and geographic range.—Bathonian to Callovian, Saudi Arabia, Jordan.