Cibicidoides

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 86

Cibicidoides sp. cf. C. basilanensis McCulloch 1977 ( Fig. 20 :10–14)

Description. Test biconvex, spiral side more strongly convex than umbilical side. Aperture slit-like, located at base of apertural face of final chamber, extending onto spiral side of test. Spiral side pitted with numerous coarse, widely spaced perforations located between raised sutures. Umbilical side has a roughened test wall with an opalescent sheen. Final one to three sutures depressed and distinct with occasional, small perforations randomly scattered across test wall. Periphery with a thick, rounded keel ( Fig. 20 :10–14).

Remarks. The available specimens from the CG have a similar test shape and ornament to Cibicidoides basilanensis McCulloch 1977 ( Haig 1997; Parker 2009), but are all incomplete ( Fig. 19 :20; Fig. 20 :1–4) resulting in the tentative taxonomic assignment. It should be noted that several other species names have been used to describe similar specimens. Similar specimens have also been described under the name Cibicidoides sp. cf. C. subhaidingeri ( Parr 1950) by Hatta & Ujiié (1992a) but Parker (2009) considered these synonymous with C. basilanensis .

The main differences between C. basilanensis and other similar species lie in the concavity of the spiral side of the test, the nature of the perforate ornament and definition of the sutures on both sides of the test. For instance, specimens identified as Cibicidoides bradyi ( Trauth 1918) by Debenay (2012) from New Caledonia appear similar but CG specimens are more conical on the spiral side and more convex on the umbilical side. Furthermore the sutures are depressed instead of flush and the spiral side perforations more abundant.

The original collections of C. basilanensis were from the Philippines ( McCulloch 1977). Hatta & Ujiié’s (1992a) material came from waters between Ishigaki and Iriomote Islands, southern Ryukyu Island Arc and Parker (2009) and Haig’s (1997) published specimens came from Ningaloo Reef and Exmouth Gulf, Western Australia, respectively.

Distribution within study area. Cibicidoides sp. cf. C. basilanensis was found in all sampled reefs of the CG. Abundance was lower on Heron Reef flat and Heron Lagoon (one to five specimens per site) and was highest at Site 43 in One Tree Lagoon 1 with 17 specimens collected.

Figures

FIGURE 19. (Unless otherwise specified all scale bars = 100 µm). 1 – 2. Uvigerina cf. U. porrecta Brady, 1879, QM # G 465988 from OTI 51. Scale bar = 50 µm. 1. Lateral view. 2. Oral view. 3 – 4. Trifarina pacifica (Albani, 1974), QM # G 465989 from OTI 51. Scale bar = 50 µm. 3. Lateral view. 4. Oral view. 5 – 6. Fijiella simplex (Cushman, 1929), QM # G 465828 from OTI 39. 5. Lateral view. 6. Oral view. 7 – 10. Eponides cf. E. repandus (Fichtel & Moll, 1798), 7. QM # G 465880 from CHANNEL, scale bar = 200 µm. 7. Spiral view. 8. Peripheral view. 9. QM # G 465881 from CHANNEL, umbilical view. Scale bar = 500 µm. 10. QM # G 465872 from CHANNEL, umbilical view. Scale bar = 200 µm. 11 – 13. Orbitina parri Collins, 1974, QM # G 466000 from OTI 47. Scale bar = 50 µm 11. Spiral view. 1 2. Umbilical view. 13. Peripheral view. 1 4 – 16. Rotorbis cf. R auberii (d’Orbigny, 1839). 1 4. QM # G 465914 from OTI 53 spiral view, scale bar = 50 µm. 1 5 – 16. QM # G 465915, umbilical view (15) peripheral view (16), scale bar for 16 = 50 µm. 1 7 – 21. Neoconorbina sp. 1. 17 – 18. QM # G 466138 from ST / HW 8, spiral (17) and peripheral (18) views. Scale bar = 50 µm. 19 – 21. QM # G 466008 from OTI 47, spiral (19), peripheral (20) and umbilical (21) views. Scale bar for 19 and 20 = 50 µm.

FIGURE 20. (Unless otherwise specified all scale bars = 100 µm). 1 – 3. Neoconorbina? sp. 1, from T 1 – 4. 1 – 2. QM # G 466023 from T 1 – 4, spiral view (1) and close-up spiral (2) view. Scale bar for 2 = 50 µm. 3. QM # G 466082 from T 1 – 2 umbilical view, scale bar = 50 µm. 4 – 5. Buliminoides williamsoniana (Brady, 1881), QM # G 465931 from WL 21. 4. Lateral view. 5. Peripheral view. 6 – 9. Pileolina? minogasaformis Ujiié, 1992. 6 – 7. QM # G 465970 from OTI 48, spiral (6) and peripheral (7) views. Scale bar for 7 = 50 µm. 8 – 9. QM # G 466016 from OTI 53, peripheral (8) and umbilical (9) views. Scale bar = 50 µm. 10 – 14. Cibicidoides cf. C. basilanensis McCulloch, 1977. 10. QM # G 466004 from OTI 53. Spiral view, scale bar = 50 µm. 11 – 12. QM # G 466005 from OTI 53, peripheral (11) and umbilical (12) views. Scale bar = 50 µm. 1 3 – 14. QM # G 466139 from ST / HW 10, peripheral (13) and umbilical (14) views. Scale bar = 50 µm. 15 – 17. Epistomaroides polystomelloides (Parker & Jones, 1865), QM # G 466009 from OTI 48. Scale bar = 200 µm. 15. Spiral view. 16. Umbilical view. 17. Peripheral view. 18 – 20. Epistomaroides punctatus (Said, 1949) 18 – 19. QM # G 465796 from T 2 – 3. 18. Spiral view. 19. Peripheral view. 20. QM # G 466014 from T 1 – 10, peripheral / spiral view.