Cypridinoidea sensu Cypridinacea Baird, 1850

Legiot, Nicolas, 2019, Silurian myodocope ostracods from Poland, Acta Palaeontologica Polonica 64 (2), pp. 379-397 : 390-392

Superfamily Cypridinoidea sensu Cypridinacea Baird, 1850

Family Cypridinidae Baird, 1850

Remarks.—The Silurian genera Calocaria Vannier, 1987 and Silurocypridina Perrier, Vannier, and Siveter, 2011 are more similar in carapace morphology to typical Recent cypridinids than to typical living cylindroleberidid or sarsiellid myodocopids (see e.g., Kornicker 1975, 1981; Horne et al. 2002). The Silurian genera differ from typical cylindroleberidids in their less elongate shape. They are like sarsiellids in general shape but lack the caudal process characteristic of that family. Moreover, typically, the females of sarsiellids lack a well-developed rostrum and rostral incisure, thus contrasting with all known specimens of the two Silurian genera, in which those features are prominently developed. Verification of the familial assignment of the two Silurian genera depends on knowledge of their soft-part morphology.

Fig. 8. Myodocope ostracod Rhomboentomozoe rhomboidea ( Barrande, 1872) , Holy Cross Mountains and Bohemia; Ludlow Series, Silurian. A. ZPAL → O.63/16, left valve with incomplete ala, in lateral view. B. ZPAL O.63/17, left valve, in lateral view (B 1), detail of the ala (B 2), detail of the posterodorsal part of the valve (B 3). C. ZPAL O.63/18, left valve with incomplete ala, in lateral (C 1), dorsal (C 2), and posterior (C 3) views, detail of the posterodorsal part of the valve (C 4). D. ZPAL O.63/19, left valve with incomplete ala, in lateral (D 1), ventral (D 2), and anterior (D 3) views, detail of the rostrum (D 4), detail of the adductorial muscle scar (D 5). E. ZPAL O.63/20, left valve with incomplete ala, in lateral view. F. ZPAL O.63/21, right valve, in anterior view showing the ala. G. Holotype, L23322, open carapace in “butterfly” position. H. ZPAL O.63/22, open carapace in “butterfly” position. I. ZPAL O.63/23, right valve, in ventral view showing the proximal part of the ala on the ventrolateral part of the valve (I 1), frontal view (I 2), detail of the muscle scar (I 3) view. All light photographs; A, B 1, C 1, C 3, D 1, E, F, stereo-pairs. A, E, F, silicone casts of external moulds; B–D, G–I, internal moulds. Scale bars: A, B 1, C 1, D 1, E, G, 1 mm; B 2, B 3, C 2 –C 4, D 2 –D 4, F, H, I, 500 μm.

Stratigraphic and geographic range.—Silurian to Recent; possibly also Ordovician ( Myodoprimigenia fistuca from the Ashgill of South Africa; Gabbott et al. 2003).