Nubeculina Cushman 1924

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 24

Nubeculina Cushman 1924

Nubeculina advena Cushman 1924 ( Fig. 5 :17–20)

1924 Nubeculina divaricata (Brady) var. advena Cushman , p. 53, pl. 19, figs 1–4. 1988 Nubeculina advena Cushman ; Haig, p. 228, pl. 3, figs 5–7.

1994 Nubeculina advena Cushman ; Loeblich & Tappan, p. 38, pl. 59, figs 1–12. 1997 Nubeculina advena Cushman ; Haig, p. 271.

2009 Nubeculina advena Cushman ; Parker, p. 148, figs 104a–j, 105a–h.

Description. See Cushman (1924, p. 53, pl. 19, figs 1–4) and Parker (2009; p. 148, figs 104a–j, 105a–h).

Remarks. This species typically has a large (up to 2.5 mm long) free, elongate, initially coiled then uniserial test that expands from the base to the oral tip. The test wall is heavily agglutinated with large grains and the aperture is circular with a series of inwardly protruding teeth giving it a crenulated appearance. This species closely resembles Reophax de Montfort 1808 with its articulated chambers and depressed sutures, but can be distinguished by the presence of a porcelaneous aperture and neck ( Fig. 5 :18).

Loeblich & Tappan (1994; pl. 59, figs 1–12) and Parker (2009; figs 104, 105) illustrate specimens displaying great variation in the length and prominence of the distinct porcelaneous neck that protrudes from the oral terminus of this species. Some specimens illustrated by Cushman (1924; pl. 19, figs 1, 3, 4) also have a quite long and distinct neck, but the neck may also be so short that it does not protrude beyond the agglutinated grains attached to the test and is therefore almost invisible ( Loeblich & Tappan 1994; Parker 2009). Parker (2009; p. 148) even noted that the porcelaneous neck is entirely absent in some of his specimens from Ningaloo Reef. In addition, the prominence of the inwardly pointing teeth can vary from small closely spaced nubs ( Loeblich & Tappan 1994, pl. 59, figs 2, 12) to very separate distinct teeth ( Cushman 1924, pl. 19, fig 4; Haig 1988, pl. 3 fig. 6; Parker 2009, figs 104d, 105d). The specimens collected from the CG were never in pristine condition and therefore, despite the porcellaneous neck and crenulate-like aperture being visible in some specimens, it was difficult to discern the presence of an everted lip evident in the specimens described by Cushman (1924) and Parker (2009).

Nubeculina advena has been collected from depths ranging from 10–120 m from the Indo-Pacific (Utilei Reef, Aua Reef , Pago Pago Harbour and Breaker Point , Samoa—Cushman 1924; Papuan Lagoon—Haig 1988; Bonaparte Depression , central Timor Sea , Cape Londonderry, Sahul Banks and Sahul Rise—Loeblich & Tappan 1994; Exmouth Gulf—Haig 1997; Ningaloo Reef—Parker 2009).

Distribution within study area. Nubeculina advena does not occur in great abundance within the sampled CG reefs with never more than seven specimens recovered per sample. However, at all sites where this species was found, even when in numbers as low as one or two specimens, there is a tendency towards comparatively greater depths. For instance, the only locations upon Heron Reef flat where N. advena was collected were the last samples of the transects, where the water was comparatively deeper. Nubeculina advena was absent from Transect 1 where water depth remained constant throughout. Additionally, this species was collected from relatively deeper areas of One Tree Lagoons 1 and 2. The site with greatest abundance from the study area was the channel sample, collected from a depth of 35 m. Nubeculina advena thus appears to prefer depths beneath tidal influence.

Figures

FIGURE 5. (Unless otherwise specified all scale bars = 100 µm). 1 – 2. Textularia jparkeri n. sp. 1. QM # G 466056 from CHANNEL with uppermost chambers broken to reveal canaliculate wall and lack of internal septula. 2. QM # G 466058 from CHANNEL broken along longitudinal axis to view internal chamber arrangement. 3 – 6. Textularia lateralis Lalicker, 1935. 3 – 4. QM # G 465958 from OTI 43 lateral (3) and oral (4) views. 5 – 6. QM # G 465892 from ST / HW 8 lateral (5) and oral (6) views. 7 – 8. Textularia sp. 1, QM # G 465803 from T 2 – 3. 7. Lateral view, scale bar = 200 µm. 8. Oral view, scale bar = 200 µm. 9 – 11. Olgia pacifica (Cushman, 1924). 8. QM # G 466132 from OTI 20, lateral view, scale bar = 200 µm. 10 – 11. QM # G 465780 from ST / HW 2 lateral (10) and oral (11) views. 12. Cornuspira planorbis Schultze, 1854, QM # G 465976 from OTI 51. Lateral view, scale bar = 50 µm. 13 – 14. Nodobaculariella cf. N. japonica Cushman & Hanzawa, 1937, QM # G 466078 from OTI 52. 13. Lateral view. 14. Oral view. 15 – 16. Wiesnerella auriculata (Egger, 1893), QM # G 465990 from T 2 – 11. 15. Oral view. 16. Lateral view. Scale bars = 50 µm. 17 – 20. Nubeculina advena Cushman, 1924 from CHANNEL. 17 – 18. QM # G 465867 lateral (17) and close-up oral (18) views. Scale bar for 17 = 500 µm. 19 – 20. QM # G 465866, lateral (19) and close-up of oral (20) views. Scale bar for 19 = 500 µm.