Silurocypridina retroreticulata Perrier, Vannier, and Siveter, 2011

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

Silurocypridina retroreticulata Perrier, Vannier, and Siveter, 2011

Fig. 2K .

1987 “Cypridinid” gen. et sp. nov. A; Siveter et al. 1987: pl. 84: 1, 3, 5, pl. 87:1, 5.

1991 “Cypridinid” gen et. sp. nov. A of Siveter et al. 1987; Siveter et al. 1991: pl. 1: 4, pl. 2:10.

1992 “Cypridinid” sp. nov. A of Siveter et al. 1987; Vannier and Abe 1992: text-fig. 2B.

1995 “Cypridinid” sp. nov. A of Siveter et al. 1987; Vannier and Abe 1995: text-fig. 16A, B.

2000 “Cypridinid” Genus A, sp. A, Siveter et al. 1987; Kornicker and Sohn 2000: 21.

2011 Silurocypridina retroreticulata sp. nov.; Perrier et al. 2011: pl. 4: 1–7, text-figs. 6, 8A, 9H.

2012 Silurocypridina retroreticulata Perrier, Vannier and Siveter, 2011 ; Perrier 2012: text-fig. 7E.

2019 Silurocypridina retroreticulata Perrier, Vannier and Siveter, 2011 ; Perrier et al. 2019: pl. 17: 6, 7, 12, 13.

Holotype: A laterally compressed right valve ( FSL 710505 ); Perrier et al. (2011: pl. 4: 4, text-fig. 9H).

Type locality: Les Buardières, Mayenne, France ( Perrier et al. 2011).

Type horizon: La Lande Murée Formation; the type horizon is within the range of the upper part of the Wenlock Series to middle part of the Ludlow Series, and currently cannot be further resolved.

Material.—Three valves, all from locality Niestachów, Holy Cross Mountain, Poland, Ludlow Series, Silurian.

Measurements (in mm).—Size range: L = 2.85, H = 2.55 ( ZPAL O.63/10, Fig. 2K ). Holotype: L = 3.46, H = 2.53 ( FSL 710505). L/H ratio and adductor muscle position for one specimen ( Fig. 3).

Description.—Valve dome-like, with nearly ovoid lateral outline; hinge short, located dorsally. Rostrum well developed, is about 15% of valve length, protrudes distinctly forward beyond the anteroventral margin of the valve. Rostral incisure well developed, rounded or angular in lateral outline. Adductor muscle scar is small, sited subcentrally, crescent-shaped convex anteriorly. Behind the adductor muscle scar and ventrally valves are reticulate, consisting of polygons with muri 50–100 μm wide and sola 100–250 μm wide. Anterodorsal part of valve (some 25% of lateral valve area) lacks ornament. A fine, narrow ridge occurs along ventral margin of the valve.

Stratigraphic and geographic range.—Ludlow Series, Holy Cross Mountains, Poland. Also known from the Silurian of France, England and Wales (see Perrier et al. 2011, 2019).

Figures

Fig. 2. Selected Silurian myodocope species, Holy Cross Mountains, Poland; Ludlow Series, Silurian. A, B. Bolbozoe anomala Barrande, 1872. A. ZPAL O.63/1, incomplete left valve. B. ZPAL O.63/2, juvenile right valve. C. Bolbozoe psittaca Perrier, Siveter, Williams, and Palmer, 2019, ZPAL O.63/3, left valve. D, E. Parabolbozoe bohemica (Barrande, 1872). D. ZPAL O.63/4, juvenile left valve. E. ZPAL O.63/5, right valve. F. Richteria migrans (Barrande, 1872), ZPAL O.63/6, left valve. G, H. Nudator angiportatus Perrier, Siveter, Williams, and Palmer, 2019. G. ZPAL O.63/7, juvenile left valve. H. ZPAL O.63/8, left valve. I, J. Nudator inflatus Perrier, Siveter, Williams, and Palmer, 2019. I. ZPAL O.63/9, right valve showing post-mortem diagenetic structures. J. ZPAL O.63/9, right valve. K. Silurocypridina retroreticulata Perrier, Vannier, and Siveter, 2011, ZPAL O.63/10, incomplete right valve. L. Silurocypridina calva Perrier, Vannier, and Siveter, 2011, ZPAL O.63/11, right valve. M. Cypridinid?, ZPAL O.63/12, right valve. All light photographs in lateral view. A–H, J, M, silicone casts of external moulds; I, K, L, internal moulds. Scale bars 1 mm, except M 2 mm.