Daghanirhynchia susanae, Feldman & Schemm-Gregory & Ahmad & Wilson, 2012

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 : 197-199

publication ID	https://doi.org/ 10.4202/app.2010.0092
persistent identifier	https://treatment.plazi.org/id/0380D832-FFFF-D364-FB77-F849183F0155
treatment provided by	Felipe
scientific name	Daghanirhynchia susanae
status	sp. nov.

Treatment

Daghanirhynchia susanae sp. nov.

Figs. 3C, 5 View Fig .

Etymology: Latinization of Susan after Susan Feldman.

http://dx.doi.org/10.4202/app.2010.0092

Holotype: Articulated specimen AMNH FI−72380 .

Type locality: Wadi Zarqa, Arda Section, Jordan.

Type horizon: Bed S−7, Mughanniyya Formation, Callovian (upper Middle Jurassic).

Material.—45 articulated shells: AMNH FI−72380, AMNH FI−72381, AMNH FI−72386, AMNH FI−72388, AMNH FI−72393, AMNH FI−723410 (sectioned) bed S−7, AMNH FI−72394, bed S−10, AMNH FI−72383, AMNH FI−72387, AMNH FI−72391, AMNH FI−72392, Mughanniyya Formation, Arda section; AMNH FI−72382, AMNH FI−72384, bed 21a, AMNH FI−72389, bed 21b, AMNH FI−72385, Hamam Formation, Arda section; GSI M 731, GSI M 732, GSI M 741, GSI M 743, GSI M 4506, GSI M 4552, GSI M 4558 (collected from the Tel el Dhahab section but beds not identified), Jordan.

Diagnosis.—Coarsely plicated Daghanirhynchia with long, narrow fold bearing 3 costae.

Description.—The shells are medium size ( Table 3), subpentagonal in outline, dorsibiconvex, maximum width at about midlength; strongly uniplicate anterior commissure, lateral commissure straight, beak suberect to erect, costae strong and coarse and narrow, numbering 12–16 but commonly 12–13, linguiform extension moderate. Anterior margin ends abruptly, stubby.

Ventral valve gently convex to almost flat in lateral view, concave in anterior profile. Sulcus originates just anterior to umbonal region, occupied by 2–3 costae. Foramen small, deltidial plates disjunct.

Dorsal valve moderately convex in lateral profile, fold originates just anterior to umbonal region, very narrow, highly elevated above flanks, occupied by 3 costae.

Dental plates parallel in posterior region of shell but diverge anteriorly from ventral floor. Teeth short, bulbous without crenulations; dorsal median septum short, reduced to low ridge, and finally disappearing at about one−third valve length. Hinge plates horizontal, very broad, and separated; septalium not preserved; crura raduliform. Secondary thickening in umbonal chambers.

Discussion.— Daghanirhynchia susanae sp. nov. differs from the type species D. daghaniensis Muir−Wood, 1935 in having coarser costae and a longer narrower fold. D. macfadyeni Muir−Wood, 1935 differs in that its fold is never raised above the level of the lateral slopes and bears a low, median fold. D. elongata Muir−Wood, 1935 is generally longer with finer costae and a shorter sulcus. The umbo in D. elongata extends further posteriorly than in D. susanae . Daghanirhynchia macfadyeni Muir−Wood, 1935 is characterised by a more convex ventral valve, a shallower shorter sulcus, and 4 costae on the fold. The costae of D. macfadyeni are finer than in D. susanae but may reach the same thickness in a few specimens. D. platiloba Muir−Wood, 1935 differs from the new species in having a less convex dorsal valve, a longer ventral umbo, and a shallower, shorter sulcus. D. kabeitensis Muir−Wood, 1935 is wider than D. susanae and has a longer ventral umbo. The size of costae and sulcus is the same as in D. susanae , D. farquharsoni Muir−Wood, 1935 is equibiconvex, whereas the specimens of D. susanae are clearly dorsibiconvex. The sulcus in D. farquharsoni is shallower than in D. susanae and sulcus and fold are rectangular in cross section, whereas in D. susanae the fold and sulcus are broadly rounded in cross section.