Quinqueloculina latidentella Loeblich & Tappan 1994

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 37-38

Quinqueloculina latidentella Loeblich & Tappan 1994 ( Fig. 8 :8, 9)

1994 Quinqueloculina latidentella Loeblich & Tappan , p. 49, pl. 80, figs 10–12.

2009 Quinqueloculina latidentella Loeblich & Tappan ; Parker, p. 217, figs 154a–f, 155a–g. 2012 Quinqueloculina latidentella Loeblich & Tappan ; Debenay, p. 123, pl. 6.

Description. See Loeblich & Tappan (1994, p. 49, pl. 80, figs 10–12) and Parker (2009, p. 217, figs 154a–f, 155a– g).

Remarks. This species is characterised by its roughly textured, non-agglutinated walls, rounded peripheries, thick, flaring peristomal lip, broad tooth and quinqueloculine chamber arrangement with depressed sutures. Chamber width and length are approximately equal and the roughened walls can contain creases or indents that are likely to have been caused by a foreign particle that has inhibited chamber growth or marked the chamber wall ( Fig. 8 :8). The aperture is terminal and flush with the oral end of the test. The thick, solid tooth varies in bifid definition sometimes bearing only a thickened tip, as in most CG specimens, or is so developed that the T-shaped branches connect to the apertural margin ( Loeblich & Tappan 1994, pl. 80, fig. 12). This latter form was not observed in the CG specimens. Loeblich & Tappan’s (1994, pl. 80, figs 10–12) original illustrations of this species do not provide a close-up of the distinct branching bifid tooth and since only one specimen is illustrated and the aperture appears to be partially blocked with carbonate debris (as observed in the CG specimens) it is possible that this material is linking the tooth to the peristomal lip. Neither Debenay (2012, p. 123) from New Caledonia nor Parker (2009, figs 153, 154) from Ningaloo Reef, observed any specimens with a bifid dentition that reached aperture margins. Instead, like the CG specimens, Parker (2009) and Debenay’s (2012) specimens either had a stout tooth with a flaring, thickened lip or a produced Y-shaped tooth. Apart from this difference in dentition, the specimens from the Timor Sea ( Loeblich & Tappan 1994), Ningaloo Reef ( Parker 2009) and New Caledonia ( Debenay 2012) vary only slightly in additional characteristics including development of a peristomal lip and in the aperture shape. The specimen illustrated by Loeblich & Tappan (1994, pl. 80 figs 10–12) only has a moderately thick lip, Debenay’s (2012) specimens show variation in lip thickness, whereas the CG and Ningaloo specimens ( Parker 2009) have moderate to very thick peristomal lips.

Quinqueloculina latidentella can be discriminated from other Quinqueloculina species by its inflated, rounded chambers, roughened test wall, broadly circular aperture and distinct peristomal lip. Two similar species are Quinqueloculina subgranulata ( Cushman 1918) and Quinqueloculina sp. 2. The test wall of Q. subgranulata tends to be more inflated and rounded and much rougher in texture than Q. latidentella . Quinquelocuina sp. 2 has weak longitudinal striae, a roughened test wall texture and the rounded aperture is proportionately much larger and bifid dentition more T-shaped than Y-shaped.

Quinqueloculina latidentella was originally collected from the Bonaparte Depression , central Timor Sea by Loeblich & Tappan (1994) from a depth of 120 m. Parker’s (2009) specimens were retrieved from Ningaloo Reef, Western Australia and Debenay’s (2012) from the northern shelf of New Caledonia from a depth of 200 m.

Distribution within study area. Quinqueloculina latidentella was not found in great abundance from the CG. Only collected from the One Tree Lagoons, this is one of the least abundant Quinqueloculina species, with no more than nine specimens collected from one site. Site 38 in One Tree Lagoon 1 had the greatest abundance of Q. latidentella .

Figures

FIGURE 8. (Unless otherwise specified all scale bars = 100 µm). 1 – 2. Quinqueloculina cf. Q. agglutinans d’Orbigny, 1839. QM # G 465786 from ST / HW 2, lateral view (1), scale bar = 200 µm and oral view (2), scale bar = 200 µm. 3 – 4. Quinqueloculina baccaerti n. sp. QM # G 465818 from OTI 36. 3. Lateral view. 4. Oral view. 5 – 7. Quinqueloculina bosciana d’Orbigny, 1839. QM # G 465978 from WL 21, lateral view (5), oral view (6). 7. QM # G 466135 from OTI 36, lateral view. Scale bar = 50 µm. 8 – 9. Quinqueloculina latidentella Loeblich & Tappan, 1994, QM # G 465825 from OTI 36. 8. Lateral view. 9. Peripheral view. 10 – 21. Quinqueloculina neostriatula Thalmann, 1950. 10 – 11. QM # G 466102 from WL 19, lateral (10) and oral (11) views. 12 – 13. QM # G 465984 from OTI 52, lateral (12) and oral (13) views. Scale bar for 13 = 50 µm. 14. QM # G 466071 from HL 40, oral view. 15. QM # G 466068 from HL 40, close-up oral view. Scale bar = 50 µm. 16 – 17. QM # G 465983 from WL 21, lateral (16) and oral (17) views. Scale bar for 16 = 200 µm. 18 – 19. QM # G 465833 from OTI 39, lateral (18) and oral (19) views. Scale bar for 18 = 200 µm. 20 – 21. QM # G 466096 from OTI 52, lateral (20) and oral (21) views.