Cymbaloporetta Cushman 1928

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 90-91

Cymbaloporetta Cushman 1928

Cymbaloporetta bradyi ( Cushman 1915) ( Fig. 21 :13–17)

1884 Cymbalopora poeyi (d’Orbigny) var., Brady, p. 637, pl. 102, fig. 14.

1915 Cymbalopora poeyi (d’Orbigny) var. bradyi, Cushman , p. 25, pl. 10, fig. 2. 1960 Cymbaloporetta bradyi (Cushman) ; Barker, p. 210, pl. 102, fig. 14.

1991 Planorbulina mediterraneansis d’Orbigny ; Triffleman et al., p. 42, pl. 1, fig. 10. 1993 Planorbulina mediterraneansis d’Orbigny ; Mather & Bennet, p. 21, fig. 11: 13. 1994 Cymbaloporetta bradyi (Cushman) ; Loeblich & Tappan, p. 152, pl. 327, figs 8–10; pl. 328, figs 1–3. 2009 Cymbaloporetta bradyi (Cushman) ; Parker, p. 552, fig. 391a–o.

2012 Cymbaloporetta bradyi (Cushman) ; Debenay, p. 236 pl. 22.

Description. See Cushman (1915, p. 25, pl. 10, fig. 2) and Parker (2009, p. 552, fig. 391a–o).

Remarks. Cymbaloporetta bradyi ( Cushman 1915) has a compressed test with a rounded periphery. The annularly arranged chambers are coarsely perforate and irregularly globular to crescentic on the spiral side and have depressed sutures. The chambers on the umbilical side are imperforate or slightly perforate with radiating sutures that are raised and have multiple slit-like apertures. The sutures usually have at least three apertures each, one opening into the umbilicus and at least two within the sutural depression ( Fig. 21 : 14, 17). This is similar to the specimens described by Parker (2009).

Cymbaloporetta bradyi closely resembles C. tabellaeformis and M. milletti . Cymbaloporetta tabellaeformis has an elongate and circular form. The elongate tabellae-form is easily distinguishable from C. bradyi due to its more elongate shape, but the circular form is much more difficult to distinguish (see remarks above for C. tabellaeformis ). Millettiana milletti is distinguished from C. bradyi by its raised, limbate sutures on the spiral side and the distinct mushroom-shaped chambers and sutures along the umbilical side. Millettiana milletti also has chambers on the spiral side that tend to be more evenly crescentic and are not as irregular or globular as C. bradyi . Interestingly, Baccaert (1987, cited by Parker 2009) considered C. bradyi and M. milletti , along with other Cymbaloporetta , as variants of the same species, but the interspecific differences between these species appear consistent and stable enough to warrant separate generic status ( Parker 2009). Mather & Bennet (1993) incorrectly assigned specimens of C. bradyi to Planorbulina mediterraneansis d’Orbigny 1826 but P. mediterranensis has a distinctly lobulate outline as opposed to being smoothly circular and the test is further compressed so that it is almost flat and the umbilical side bears none of the radiating raised chambers with slit-like apertures protruding out the side wall that is diagnostic of Cymbaloporetta .

Brady’s original specimens ( Barker 1960; 1884) were collected from Torres Strait at a depth of 275 m and from Papua New Guinea at a depth of 68 m . Cushman’s (1915) collections originated off the Hawaiian Islands at Albatross Station from a depth of 716 m . The distribution of C. bradyi is mostly Indo-Pacific and Caribbean (Nicaraguan Rise—Triffleman et al. 1991; the CG—Mather & Bennet 1993; the Beagle Gulf at 53 m and Western Timor Sea at 146 m—Loeblich & Tappan 1994; Exmouth Gulf—Haig 1997; Ningaloo Reef—Parker 2009; New Caledonia down to 20 m— Debenay 2012).

Distribution within study area. Cymbaloporetta bradyi was collected from all sampled reefs, but abundance was low in samples from Sykes Reef and the channel. The greatest abundance was at site 48 at the western edge of One Tree Lagoon 3 which was a relatively shallow (~ 3 m deep) site located before the western reef platform that marks the edge of One Tree Reef. The abundance of C. bradyi at this site was at least four times greater than any other site, but the cause of such a greatly increased abundance requires further investiagion.

Cymbaloporetta bradyi was the most abundant species of Cymbaloporetta that was collected live. Live specimens were most common in One Tree Lagoons and reached an abundance of five specimens per site at site 48 in One Tree Lagoon 3. Live specimens were also collected in samples from Wistari and Heron Lagoons and Heron Reef flat.

Cymbaloporetta sp. cf. C. grandis ( Cushman 1934) ( Fig. 21 :18–20)

Remarks. The specimen collected was assigned due to its large Cymbaloporetta -like test with a deeply domed shape atop the balloon chamber. Greatly resembling specimens collected by Debenay (2012) from New Caledonia, the chambers of the final circle in the initial test section hang down over the balloon chamber when viewed in periphery. Chambers are bulging and coarsely perforate across both initial test section and balloon chamber with numerous, large rimmed holes across the base in a radiating star-like pattern. No confidant assignment could be made due to only one specimen being recovered.

Distribution within study area. Only one specimen was recovered from Heron Reef flat, Transect 2.

Figures

FIGURE 21. (Unless otherwise specified all scale bars = 100 µm). 1 – 6. Epistomaroides punctatus (Said 1949). 1 – 2. QM # G 466014 from T 1 – 10 umbilical (1) and peripheral (2) views. 3 – 4. QM # G 466013 from T 1 – 10, peripheral spiral (3) and umbilical (4) views. Scale bar = 200 µm. 5 – 6. QM # G 465885 from ST / HW 4, umbilical (5) and peripheral (6) views. Scale bar = 200 µm. 7 – 12. Cymbaloporella tabellaeformis (Brady, 1884). 7 – 8. QM # G 466011 from OTI 48, spiral (7) and peripheral (8) views. 9 – 10. QM # G 465991 from OTI 51 peripheral (9) and umbilical (10) views. Scale bar for 9 = 50 µm. 11 – 12. QM # G 466084 from OTI 51 spiral (11) and umbilical (12) views. 13 – 17. Cymbaloporetta bradyi (Cushman, 1915). 13. QM # G 465886 from ST / HW 4, spiral view. 14. QM # G 465887 from ST / HW 4, umbilical view. 15. QM # G 465808 from T 2 – 3, umbilical view. 16 – 17. QM # G 466010 spiral (16) and peripheral (17) views. 18 – 20. Cymbaloporetta cf. C. grandis (Cushman, 1934), QM # G 466037 from T 2 – 1. 18. Peripheral view. 19. Peripheral / float chamber view. 20. Spiral view.