Sorites Ehrenberg 1839

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 68-70

Sorites Ehrenberg 1839

Sorites orbiculus Forskål 1775 ( Fig. 16 :9–12)

1775 Nautilus orbiculus Forskål , p. 125.

1963 Orbitolites orbiculus (Forskål) ; Smout, p. 569, pl. 4, figs 3, 4.

1978 Sorites orbiculus (Forskål) ; Cheng & Zheng, p. 198, pl. 17, figs 1–9; pl. 31, figs 1–3; pl. 32, fig. 1. 1987 Sorites orbiculus (Forskål) ; Loeblich & Tappan, p. 107, pl. 419, figs 4–10. 1993 Sorites orbiculus (Forskål) ; Hottinger et al., p. 72, pl. 83, figs 1–13. 1994 Sorites orbiculus (Forskål) ; Gudmundsson, p. 123, figs 32–35.

1994 Sorites orbiculus (Forskål) ; Loeblich & Tappan, p. 63, pl. 112, figs 6–8. 1995 Sorites orbiculus (Forskål) ; Lobegeier, p. 77, pl. 4, figs 6, 7.

2012 Sorites orbiculus (Forskål) ; Debenay, p. 131, pl. 4.

Description. See Gudmundsson (1994, p. 123, figs 32–35) and Hottinger et al. (1993, p. 72, pl. 83, figs 1–13).

Remarks. Sorites orbiculus ( Forskål 1775) is characterised by a discoidal porcelaneous, dimorphic test with a commonly biplanar, but slightly thickened periphery. The chambers are distinctly subdivided and have radially flaring chamberlets. Apertures on the equatorial plane or peripheral face form rough rows and are usually circular, but sometimes have a lemniscate shape where opposing apertures have not properly separated during early ontogeny ( Fig. 16 :9–12).

Sorites orbiculus differs from M. vertebralis by having more distinct, flaring radial chamberlets and less numerous and randomly scattered apertures along the equatorial plane.

Like M. vertebralis , S. orbiculus is a widely distributed taxon (Gulf of Aqaba—Hottinger et al. 1993; Hawaiian Islands , Mediterranean Sea, the Caribbean, Canton Island, Samoa, British Solomon Islands, Tuamoto Archipelago, Japan, Gaspar Strait, Bikini Atoll and Marshall Islands—Gudmundsson 1994; Sahul Shelf—Loeblich & Tappan 1994; Low Isles, GBR—Lobegeier 1995; Chesterfield, New Caledonia and southwestern lagoon down to 40 m—Debenay 2012).

Distribution within study area. Within the CG, S. orbiculus occurred at all sites, except Sykes Reef and the channel sample between Wistari and Heron. Abundance ranged from one to fourteen specimens per sample site with the greatest abundance occurring at site 37 in Heron Lagoon, site 39 in One Tree Lagoon 1, site 18 in One Tree Lagoon 3 and site 15 in Wistari Lagoon.

Figures

FIGURE 16. (Unless otherwise specified all scale bars = 100 µm). 1 – 8. Marginopora vertebralis Quoy & Gaimard, 1830. 1. QM # G 466020 from T 1 – 2, close-up oral view. Scale bar = 500 µm. 2 – 4. QM # G 465967 from OTI 48, lateral (2), oral (3) and peripheral (4) views. Scale bar for 2 = 200 µm. 5 – 8. QM # G 465961 from T 1 – 2. 5. Lateral view showing internal structure, scale bar = 500 µm. 6. Oral view, scale bar = 500 µm. 7. Close-up oral view. 8. Close – up oral view, scale bar = 10 µm. 9 – 12. Sorites orbiculus Forskål, 1775. 9 – 10. QM # G 466115 from ST / HW 4, lateral (9) and oral (10) views. 11 – 12. QM # G 465936 from HL 37, lateral (11) and close-up oral (12) views. Scale bar for 18 = 200 µm. 13 – 14. Conicospirillinoides sp. 1, QM # G 465963 from OTI 51. Scale bar = 50 µm. 13. Apical view. 14. Peripheral view. 15. Planispirillina inaequalis Brady, 1879, QM # G 465942 from OTI 12. Ventral view. 16 – 20. Planispirillina spinigera (Chapman, 1900). 16 – 17. QM # G 465962 from OTI 20, dorsal (16) and peripheral (17) views. 18 – 20. QM # G 465968 from OTI 51, dorsal (18), peripheral (19) and ventral lateral (20) views. Scale bar for 19 = 50 µm.