Siphonaperta Vella 1957

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 32-33

Siphonaperta Vella 1957

Siphonaperta crassa Vella 1957 ( Fig. 7 :7, 8)

Description. See Vella (1957, p. 19, pl. 4, figs 62, 64–66).

Distribution within study area. This species is represented by only two specimens from site 10 of ST/HW transect and site 6 of Transect 3 on the reef rampart of Heron Reef.

Siphonaperta distorqueata ( Cushman 1954) ( Fig. 7 :9, 10)

1954 Quinqueloculina distorqueata Cushman ; in Cushman et al., p. 333, pl. 83, fig. 27. 1987 Quinqueloculina distorqueata Cushman ; Baccaert, p. 86, pl. 40, figs 4–7. 1988 Quinqueloculina distorqueata Cushman ; Haig, p. 233, pl. 5, figs 26–28. 1997 Quinqueloculina distorqueata Cushman ; Haig, p. 272, fig. 3: 25.

2001 Quinqueloculina distorqueata Cushman ; Lobegeier, p. 292, pl. 8, figs 8–10. 2009 Quinqueloculina distorqueata Cushman ; Parker, p. 195, figs 138a–c, 139a–h. 2012 Quinqueloculina distorqueata Cushman ; Debenay, p. 122, pl.7.

Description. See Cushman et al. (1954, p. 333, pl. 83, fig. 27) and Parker (2009, p. 195, figs 138a–c, 139a–h).

Remarks. The diagnostic features of this species include a broad test with a blunt base, a short neck terminated by a circular aperture hosting a short, sometimes bifid, tooth. The aperture has a slight lip and the chambers have acute peripheries that are slightly keeled and irregularly curved around the test. The acute chamber periphery results in a compressed and distorted test with distinct sutures. The test walls have a roughened texture ( Fig. 7 :9, 10).

Siphonaperta distorqueata Cushman (in Cushman et al. 1954) can be distinguished by the presence of a broad test with pinched and twisted chamber peripheries and the roughened texture of the test walls. The original description of S. distorqueata by Cushman (in Cushman et al. 1954, p. 333) describes a slender neck lacking a definite apertural tooth. Most specimens described by Haig (1988; 1997) and Parker (2009) clearly display a somewhat stunted and more broad neck and a distinct T-shaped tooth identical to specimens collected from the CG. Siphonaperta distorqueata was originally reported from Rongerik Lagoon, Marshall Islands from a depth of 46 m and from the lagoons at Rongelap, Bikini and Eniwetok Atolls ( Cushman et al. 1954). It has also been reported from the Indo-Pacific (GBR—Baccaert 1987 and Lobegeier 2001; Papuan Lagoon—Haig 1988; Exmouth Gulf— Haig 1997; Ningaloo Reef—Parker 2009; New Caledonia southwestern lagoon—Debenay 2012).

Distribution within study area. The sites of greatest abundance were all from One Tree Lagoon 1. This species was not found in Sykes Reef samples and abundances were distinctly low in the channel sample and shallow water sites such as the transect samples from Heron Reef flat and the shallower areas of Heron, One Tree and Wistari lagoons. The difference is so distinct that it could be said that this species prefers relatively shallow marine environments that are beneath tidal influence.

Figures

FIGURE 7. (Unless otherwise specified all scale bars = 100 µm). 1 – 2. Spiroloculina foveolata Egger, 1893, QM # G 465816 from OTI 36. 1. Lateral view. 2. Oral view. 3 – 4. Spiroloculina sp. 1, QM # G 465834 from OTI 39. 3. Lateral view. 4. Peripheral view. Scale bars = 200 µm. 5 – 6. Pitella haigi Langer, 1992, QM # G 465806 from T 2 – 3. 5. Lateral view. 6. Oral view. 7 – 8. Siphonaperta crassa Vella, 1957, QM # G 466065 from T 3 – 6. 7. Lateral view. 8. Oral view. 9 – 10. Siphonaperta distorqueata (Cushman, 1954), QM # G 465912 from OTI 52. 9. Lateral view. 10. Oral view. 11 – 14. Hauerina earlandi Rasheed, 1971, scale bars = 50 µm. 11 – 12. QM # G 465987 from OTI 39 lateral (11) and peripheral (12) views. 13 – 14. QM # G 466103 from OTI 51 lateral (13) and oral (14) views. 15 – 18. Hauerina pacifica Cushman, 1917. 15 – 16. QM # G 465899 from ST / HW 10. Lateral view (15) and close-up oral view (16). Scale bar = 10 µm. 17 – 18. QM # G 466125 from T 1 – 8. 17. Lateral view. 18. Oral view. 19 – 20. Quinqueloculina cf. Q. agglutinans d’Orbigny, 1839, QM # G 465807 from T 2 – 3, lateral view (19) and peripheral view (20).