Pyrgo williamsoni (Silvestri, 1923)

Symphonia, Tabita K. & Senthil, Nathan D., 2019, Taxonomic notes on Recent Foraminifera from the Continental Shelf-Slope Region of Southwestern Bay of Bengal, East Coast of India, Palaeontologia Electronica (55 A) 22 (3), pp. 1-89 : 69

Pyrgo williamsoni (Silvestri, 1923)

Figure 20.8

1923 Biloculina williamsoni Silvestri , p. 73.

2003 Pyrgo williamsoni (Silvestri) ; Murray, p. 17, pl. 4, figs. 7-8.

2010 Pyrgo williamsoni (Silvestri) ; Margreth, p. 103, pl. 9, fig. 6a-c.

Description. Test ovate, elongate, tapering at the apertural end, aboral end broad, wall porcelaneous, imperforate, surface smooth; chambers added obliquely, biloculine chamber arrangement, coiling involute, periphery subacutely rounded, sutures distinct, slightly depressed; aperture elliptical, with a simple bifid tooth.

Figures

FIGURE 20. 1, Parahauerinoides fragilissima (Brady, 1884) in dorsal view (scale equals 300 μm). 2, Pseudotriloculina sp., in dorsal view (scale equals 100 μm). 3, Pyrgo denticulata (Brady, 1884) in ventral view (scale equals 500 μm). 4. Pyrgo inornata (d’Orbigny, 1846) in ventral view (scale equals 300 μm). 5-6, Pyrgo oblonga (d’Orbigny, 1839a) in dorsal view (scale equals 300 μm) (5) and in ventral view (scale equals 300 μm) (6). 7, Pyrgo sp. in ventral view (scale equals 300 μm). 8, Pyrgo williamsoni (Silvestri, 1923) in ventral view (scale equals 300 μm). 9-10, Triloculina echinata d’Orbigny, 1826 in dorsal view (scale equals 200 μm) (9) and in ventral view (scale equals 200 μm) (10). 11-12, Triloculina insignis (Brady, 1881) in dorsal view (scale equals 300 μm) (11) and in ventral view (scale equals 200 μm) (12). 13-14, Triloculina oblonga (Montagu, 1803) in dorsal view (scale equals 300 μm) (13) and in ventral view (scale equals 300 μm) (14). 15, Triloculina schreiberiana d’Orbigny, 1839a in dorsal view (scale equals 200 μm). 16-17, Triloculina terquemiana (Brady, 1884) in lateral view (scale equals 400 μm) (16) and in dorsal view (scale equals 300 μm) (17). 18, Triloculina tricarinata d’Orbigny, 1826 in apertural view (scale equals 200 μm).