Eponides de Montfort 1808

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 81

Eponides de Montfort 1808

Eponides sp. cf. E. repandus ( Fichtel & Moll 1798) ( Fig. 19 :7–10)

Description. Test trochospiral, evolute on spiral side and involute on umbilical, unequally biconvex. Periphery smooth, slightly lobulate around weakly inflated chambers with a thin carina. Chambers crescent shaped on spiral side and subtriangular on umbilical side. Sutures radial, curved and depressed on umbilical side, raised on spiral side. Interiosutural area finely perforate to smooth. Clustered pustular ornament occasionally present on initial chambers on both sides of test. Outer edge of final chamber on umbilical side of test extended to form a thin, apertural face pitted with areal apertures.

Remarks. These specimens are only tentatively assigned to Eponides repandus (Fichtel & Moll 1978) due to the highly damaged nature of the available material however, the distinct features of this species, including the areal apertures on the umbilical side of the test, test shape and ornament ( Fig. 19 :7–10) are apparent.

Eponides repandus is a common species in reef environments ( Bock et al. 1971; Hatta & Ujiié 1992a; Hottinger et al. 1993; Loeblich & Tappan 1994; Parker 2009), but specimens are known to display variation in the test ornament. Some specimens appear to have completely smooth tests ( Hatta & Ujiié 1992a; Hottinger et al. 1993; Loeblich & Tappan 1994) whilst others have more roughened textures due to the presence of fine perforations and their variation in size ( Bock et al. 1971; Parker 2009; Debenay 2012). The location, size and density of the pustulate ornament also varies on the CG specimens and other examples ( Bock et al. 1971; Hatta & Ujiié 1992a; Hottinger et al. 1993; Loeblich & Tappan 1994; Parker 2009). Capricorn Group specimens all possessed roughly textured test walls on their aboral sides due to poor preservation and sections of fine perforations divided by imperforate, raised sutures ( Fig. 19 :7, 8). The amount and intensity of pustulate ornament however, varies between CG specimens. Additionally, areal sutures vary in number and proliferation along the apertural face extension with E. repandus . Those CG specimens with a relatively large apertural face have areal sutures evenly distributed across the face, similar to the specimens described by Hatta & Ujiié (1992a) and Debenay (2012). In contrast, the specimens described by Parker (2009) and Hottinger et al. (1993) have fewer areal apertures with the largest along the periphery of the test. Furthermore, the areal apertures on the specimens illustrated by Bock et al. (1971, pl. 21, figs 6, 7) and Lobelich & Tappan (1994, pl. 268, figs 10–13) are further differentiated by having a number of areal apertures between the two extremes. The apertural face is also angled down sharply back towards the test whereas other examples, like specimens collected from the CG, have only a gently sloping face.

The original description of E. repandus by Fichtel & Moll (1798) is based on material from the Mediterranean Sea. This species has a global distribution (Florida Bay—Bock et al. 1971; Ryukyu Island Arc—Hatta & Ujiié 1992a; Gulf of Aqaba—Hottinger et al. 1991a and 1993; northeast Timor Sea from 72 m—Loeblich & Tappan 1994; restricted to deeper waters in gaps between reefs at Ningaloo Reef—Parker 2009; New Caledonia southern shelf from 30+ m—Debenay 2012).

Distribution within study area. Eponides repandus was only found in low abundance (one to six specimens per site) in One Tree lagoons and the channel sample. The site of greatest abundance is site 34 in One Tree Lagoon 1, which is the centre of the deepest One Tree Lagoon. This distribution matches those previously reported by Loeblich & Tappan (1994) and Parker (2009).

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.