Parabolbozoe bohemica ( Barrande, 1872 )

Legiot, Nicolas, 2019, Silurian myodocope ostracods from Poland, Acta Palaeontologica Polonica 64 (2), pp. 379-397 : 384-385

Parabolbozoe bohemica ( Barrande, 1872)

Fig. 2D, E .

1868 Bolbozoe Bohemica Barr. ; Bigsby 1868: 200.

1872 Bolbozoe Bohemica Barr. ; Barrande 1872: 502, pl. 27: 14 (= same specimen as fig. 17 upper) and 17 lower (= 2 specimens on slab NM-CE1192), 15, 16, 18, 20 (= NM original specimen numbers 1608, 1609, 1611, 1613), 19 (holotype, specimen NM-L 23658 [ex. CE1193]) .

1896 Bolbozoe polonica nov. sp.; Gürich 1896: 378, pl. 15: 12a–c.

1898 Cypridina? polonica ( Bolbozoe, Gürich ); Jones1898: 339, pl. 17: 16.

1900 Bolbozoe (?) bohemica Barr. ; Canavari 1900: 205, text-fig. 15a–c (specimen I 96).

1934 Bolbozoe bohemica Barrande ; Bassler and Kellett 1934: 215.

1936 Bolbozoe bohemica Barrande ; Bouček 1936: 63, text-fig. 4.

1937 Bolbozoe (?) bohemica Barr. ; Chaubet 1937: 188, pl. 7: 18 a, 18b (specimens UMC-IP-VP 1, UMC-IP-VP 6).

1954 Bolbozoe bohemica Barrande ; Hughes 1954: 42.

1958 Bolbozoe bohemica Barrande ; Pokorný 1958: 315, text-fig. 1044.

1961 Bolbozoe bohemica Barrande ; Sylvester-Bradley 1961: 396, text-figs. 316.1a, 18b;? 316.1g –i.

1984 Bolbozoe bohemica Barrande ; Siveter 1984: pl. 2: 7–11; text-figs. 2, 3.

1987 “ Bolbozoe ” cf. bohemica Barrande ; Siveter et al. 1987: pl. 84: 6–8, pl. 87: 6, 7; text-fig. 5E, F.

1988 Bolbozoe (Parabolbozoe) bohemica Barrande ; Přibyl 1988: 120.

1990 “ Bolbozoe ” bohemica Barrande ; Siveter and Vannier 1990: text-fig. 7g –i, 17, 23.

1991 Parabolbozoe cf. bohemica Barrande ; Siveter et al. 1991: pl. 2: 9, 11, pl. 3: 2, 6.

1992 “ Bolbozoe ” cf. bohemica Barrande ; Vannier and Abe 1992: text-fig. 1B.

2009 Parabolbozoe bohemica ( Barrande, 1872) ; Gnoli et al. 2009: pl. 2: 18, 22–27,?16,?17,?19–21.

2009 Parabolbozoe bohemica ( Barrande, 1872) ; Siveter 2009: 54, pl. 8: 9.

2011 Parabolbozoe bohemica ( Barrande, 1872) ; Perrier et al. 2011: pl. 3: 1–9, 18, 19, text-figs. 6, 7F, 8A.

2013 Parabolbozoe bohemica Barrande, 1872 ; Perrier and Siveter 2013: text-fig. 22.6B.

2015 Parabolbozoe bohemica? Barrande, 1872 ; Williams et al. 2015: text-fig. 2k–l.

2019 Parabolbozoe bohemica ( Barrande, 1872) ; Perrier et al. 2019: pl. 6: 1–13; pl.7: 1–10.

Lectotype: A left valve, NM-L 23658 (ex. CE1193); Barrande (1872: pl. 27: 19, in reverse); Perrier et al. (2011: pl. 3: 1); designated by Bouček (1936: 63).

Type locality: Praha-Malá Chuchle, Vyskočilka, Czech Republic.

Type horizon: Kopanina Formation, Ludlow Series (stratigraphical division e2 of Barrande 1872; horizon with the trilobite “ Cromus ” beaumonti ).

Material.—Tens of valves from two localities (Niestachów and Kielce), Holy Cross Mountains, Poland; Ludlow Series, Silurian.

Measurements (in mm).—Size range: L = 2.95, H = 2.35 ( ZPAL O.63/26) to L = 8.75, H = 6.35 ( ZPAL O.63/5; Fig. 2E ). Lectotype: L = 11.25, H = 8.10 ( NM-L 23658). L/H ratio and adductor muscle position for seven specimens from one locality ( Fig. 3).

Description.—Adult valve is sub-ovoid in lateral outline, gently curved dorsally and ventrally, posteriorly tapering slightly. Bulb is large, anterodorsal, has centre above valve mid-height, extends posteriorly to almost line of maximum valve height and ventrally to below valve mid-height; outline is sub-circular, with a slight indentation opposite the rostrum. Rostrum is large, hook-like, generally with a pointed end. Rostral incisure is well developed, below which the valve has a forward pointing projection. Caudal process well developed, pointed in early instars, subdued and rounded in late instars. Maximum valve length is at about the level of end of rostrum; maximum valve height is at about valve mid-length; maximum valve width is at the crest of bulb. A narrow, fairly deep sulcus flanks the bulb posteriorly and ventrally, is widest dorsally and at its mid-length site of adductor muscle scar. In posterior one-third of valve a narrow S-shaped sulcus skirts around dorsal and anterior base of caudal process and projects forward near valve ventral margin. Adductor muscle scar prominent, consisting of about 18–24 sub-parallel, radiating and alternating ridges and furrows arranged in a double series feather-like pattern. Reticulation covers external valve surface, including ventral part of bulb; consists of elongate polygons (muri 80–200 μm wide; fossae 100–500 μm wide), many hexagonal. Posteriorly and centrally in some large valves some polygons are extremely elongate, almost resembling corrugation. Centrodorsally in some valves 3–5 pore-bearing tubercles (diameter about 100 μm) occur atop the muri. In other valves 8–10 pore-bearing tubercles (diameter about 100 μm) occur atop the muri arranged in two rows ventrally. During ontogeny, size of bulb becomes relatively smaller and valve shape changes from almost circular to ovoid and density of reticulations decreases.

Remarks.— Bolbozoe polonica Gürich, 1896 was established on a single specimen, assumed lost during World War II. Gürich’s (1896) description and drawings indicate that the species had two sulci, a feather-like adductorial muscle scar and reticulated ornament like that of P. bohemica and it is probably its junior synonym.

Stratigraphic and geographic range.—Ludlow Series, Holy Cross Mountains, Poland. Also known from the upper part of the Wenlock and lower part of the Ludlow series of the Czech Republic, France, Sardinia ( Perrier et al. 2011), England and Wales ( Perrier et al. 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.