Miliolinella Wiesner 1931

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 52-53

Miliolinella Wiesner 1931

Miliolinella circularis ( Bornemann 1855) ( Fig. 11 :12–15)

1855 Triloculina cirularis Bornemann , p. 349, p. 19, fig. 4

1884 Miliolinella circularis (Bornemann) ; Brady, pl. 5, figs 13, 14.

1960 Miliolinella subrotunda (Montagu) ; Barker, p. 10, pl. 5, figs 13, 14. 1993 Miliolinella sp. C; Hottinger et al., p. 53, pl. 40, figs 4, 5.

1994 Triloculinella pilasensis ( McCulloch 1977) ; Loeblich & Tappan, p. 57, pl. 99, figs 1–6. 2009 Miliolinella circularis (Bornemann) ; Parker, p. 120, fig. 85a–c.

2012 Miliolinella circularis (Bornemann) ; Debenay, p. 109, pl.8.

Description. See Hottinger et al. (1993, p. 53, pl. 40, figs 4, 5) and Parker (2009, p. 120, fig. 85a–c).

Remarks. This species is characterised by low, inflated chambers, a circular outline, a broad terminal aperture bordered by a thick peripheral lip and blocked by a large, concave basal flap ( Fig. 11 :12–15).

Miliolinella circularis ( Bornemann 1855) has often been described under different names since being established. Brady (1884) originally assigned his Challenger specimens to M. circularis , however, according to Jones (1994) these were later re-assigned to Miliolinella subrotunda (Montagu 1803) by Wiesner (1923) and Barker (1960) also republished Brady’s (1884) original specimens under this eponym. Thalmann (1932) assigned the specimens to Triloculina subrotunda (Montagu) , Hofker (1976) to M. circularis and Jones (1994) considers the Challenger specimens M. subrotunda . Here, the CG specimens are only synonymised with the specimens on pl. 5, figs 13, 14 of Brady’s (1884) M. circularis , not pl. 4. The specimen on pl. 4 (fig. 3, Brady, 1884) appears to bear a slightly produced aperture which sits flat atop the final chamber and the basal flap extends across the aperture, so large only a slit remains open. None of the CG specimens possessed these attributes but rather the final chamber’s aperture curves over the opposing chamber and the basal flap blocks upward, not across the aperture, leaving a larger space ( Fig. 11 :12, 13). Miliolinella sp. C of Hottinger et al. (1993) is strikingly similar to the specimens collected from the CG, but Hottinger et al. (1993) also noted a resemblance to Miliolinella laplataensis McCulloch 1977 based on its thick, peristomal lip having a slight backward turn. As noted by Parker (2009), Miliolinella heligmateira Loeblich & Tappan 1994 also shares a number of similar features with M. circularis including a circular outline, peristomal lip and aperture (compare Loeblich & Tappan 1994, pl. 89, figs 12–14 with Fig. 11 :12–15), but has far more compressed chambers than either Parker’s (2009) specimens or those from the CG. Miliolinella heligmateira also lacks the distinctively large, concave basal flap that blocks the aperture. Loeblich & Tappan (1994, pl. 99, figs 1–6) figure specimens they assigned to Triloculinella pilasensis ( McCulloch 1977) , but have all of the diagnostic features of M. circularis including the inflated chambers and distinct aperture basal flap. These specimens are here regarded as synonyms of M. circularis .

Miliolinella circularis was originally reported by Bornemann (1855) from an Oligocene septarian concretionrich marine clay from Hermsdorf, Germany and has a global distribution ( South Atlantic from 182–274 m—Brady 1884; Gulf of Aqaba—Hottinger et al. 1993; Beagle Gulf—Loeblich & Tappan, 1994; Ningaloo Reef—Parker 2009; New Caledonia down to 20 m—Debenay 2012).

Distribution within study area. Miliolinella circularis was collected from all three One Tree Lagoons with an average of five specimens per site. Site 48 in One Tree Lagoon 3 was the most abundant site for this taxon followed by sites 36 and 43 in One Tree Lagoon 1. This taxon was not collected from Sykes Reef and has very patchy distribution and low abundance (only one to four specimens per site) from Heron Reef flat, Lagoon and Wistari Reef.

Figures

FIGURE 11. (Unless otherwise specified all scale bars = 100 µm). 1 – 2. Quinqueloculina sp. 3, QM # G 465918 from WL 1. 1. Lateral view. 2. Oral view. 3 – 5. Quinqueloculina sp. 4, QM # G 465831 from OTI 39. 3. Lateral view. 4. Oral view. 5. Peripheral view. 6 – 7. Quinqueloculina sp. 5, QM # G 465782 from ST / HW 2. 6. Lateral view, scale bar = 200 µm. 7. Oral view, scale bar = 200 µm. 8 – 9. Quinqueloculina sp. 6, QM # G 465910 from T 3 – 2. 8. Lateral view. 9. Peripheral view. 10 – 11. Quinqueloculina sp. 7, QM # G 465951 from S 8. 10. Lateral view, scale bar = 500 µm. 11. Close-up lateral view, scale bar = 50 µm. 12 – 15. Miliolinella circularis (Bornemann, 1855). 12 – 13. QM # G 465898 from ST / HW 10, lateral (12) and oral (13) views. 14 – 15. QM # G 465980 from OTI 54, lateral (14) and oral (15) views. 16 – 17. Miliolinella sp. 1, QM # G 465944 from OTI 20. 16. Lateral view. 17. Oral view. 18 – 20. Miliolinella sp. 2, QM # G 465901 from ST / HW 10. 18. Lateral view. 19. Lateral view. 20. Oral view.