Baculogypsina Sacco 1893

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 100-102

Baculogypsina Sacco 1893

Baculogypsina sphaerulata ( Parker & Jones 1860) ( Fig. 24 :1–4)

1860 Orbitolina sphaerulata Parker & Jones , p. 33, fig. 8.

1924 Baculogypsina sphaerulatus (Parker & Jones) ; Cushman, p. 44, pl. 15, figs 1–3. 1965 Baculogypsina sphaerulata (Parker & Jones) ; Jell et al., p. 278, pl. 44, fig. 6. 1984 Baculogypsina sphaerulata (Parker & Jones) ; Hallock, p. 251, fig. 1: 12.

1992a Baculogypsina sphaerulata (Parker & Jones) ; Hatta & Ujiié, p. 199, pl. 44, figs 3–5. 1995 Baculogypsina sphaerulata (Parker & Jones) ; Lobegeier, p. 84, pl. 6, fig. 9.

1999 Baculogypsina sphaerulata (Parker & Jones) ; Hohenegger et al., p. 153, fig. 27. 2002 Baculogypsina sphaerulata (Parker & Jones) ; Lobegeier, p. 215, pl. 2, figs 15–17. 2002 Baculogypsina sphaerulata (Parker & Jones) ; Yordanova & Hohenegger, p. 198, pl. 33, figs 4–6. 2003 Baculogypsina sphaerulata (Parker & Jones) ; Langer & Lipps, p. 151, fig. 7Df. 2004 Baculogypsina sphaerulata (Parker & Jones) ; Saraswati et al., p. 341, pl. 1, fig. 7. 2012 Baculogypsina sphaerulata (Parker & Jones) ; Debenay, p. 234, pl. 22.

Description. See Cushman (1924, p. 44, pl. 15, figs 1–3), Hohenegger et al. (1999, p. 153, fig. 27) and Yordanova & Hohenegger (2002, p. 198, pl. 33, figs 4–6).

Remarks. This taxon is characterised by a large, biconvex test with the initial planispiral growth stage being followed by cyclic chamber addition, often on the horizontal plane, giving the test a spherical shape. The test has four to nine spines developed from the inner embryonic spiral and the ornament consists of numerous pustules scattered over the test ( Fig. 24 :1–4).

Baculogypsina sphaerulata ( Parker & Jones 1860) shows intraspecific variation in the number of spines (either five or more than six) protruding from inner side of the test and the extent to which the exterior chambers cover the spines. In some instances, the outermost test wall partially extends up the spines resulting in a tapering appearance ( Cushman 1924; Lobegeier 1995; Yordanova & Hohenegger 2002; Langer & Lipps 2003; Saraswati et al. 2004; Debenay 2012). In other cases, the spines form distinct protrusions that appear unrelated to the outer test wall ( Hatta & Ujiié 1992a; Hohenegger et al. 1999; Debenay 2012). Within CG collected specimens both tapering forms with five spines ( Fig. 23 :4, 5) and protruding forms with six or more spines were collected ( Fig. 23 :2, 3).

Baculogypsina sphaerulata is closest to Baculogypsinoides spinosus Yabe & Hanzawa 1930 . Both taxa have a similar internal structure, chamber arrangement and protruding spines. However, B. spinosus only has three to four spines and these tend to be proportionately thicker in relation to test size; supplementary spines also cover the external test surface.

The type specimens of B. sphaerulata were collected from New Zealand, Fiji and New Caledonia ( Parker & Jones 1860; Ellis & Messina 1940). Based on material collected off Utileo Reef, Pago Pago Harbour, Samoa, Cushman (1924) observed that B. sphaerulata is not widely distributed and prefers shallow water environments. This taxon has a predominantly western Pacific distribution (GBR—Jell et al. 1965, Lobegeier 1995; Palau, Western Caroline Islands—Hallock 1984; Ryukyu Island Arc—Hatta & Ujiié 1992a, Hohenegger et al. 1999, Yordanova & Hohenegger 2002, Saraswati et al. 2004; Papua New Guinea—Langer and Lipps 2003; New Caledonia—Debenay 2012). This species is almost exclusively found within shallow waters (<5 m) living on algal thalli or growing on coral in areas with high coral coverage including the inner reef flat and reef crest areas ( Jell et al. 1965; Hallock 1984; Debenay 2012).

Distribution within study area. Baculogypsina sphaerulata is the second most abundant species from the CG. Collected from all reefs, except for the channel sample, the distribution of B. sphaerulata conforms to previous observations that it is a common species in shallow, intertidal waters, and only occurs in relatively low abundance in deeper lagoonal settings ( Cushman 1924; Jell et al. 1965; Hallock 1984; Hohenegger et al. 1999; Yordanova & Hohenegger 2002). For instance, the two sites with highest abundance of B. sphaerulata in Wistari Lagoon were the two shallowest sites where abundance was twenty to thirty times higher. Interestingly, on Heron Reef flat the greatest abundance was found on the reef crest or outermost inner reef flat at site 8, along ST/HW transect or at sites 13 and 15 along Transect 2. At site 28, Sykes Reef, the average number of specimens per site was similarly high (215 specimens per site).

Figures

FIGURE 23. (Unless otherwise specified all scale bars = 100 µm). 1 – 3. Acervulina mabahethi (Said, 1949). 1 – 2. QM # G 465999 from T 2 – 11, spiral view (1) and umbilical (2) views. Scale bar = 200 µm. 3. QM # G 466007 from OTI 47 spiral view. Scale bar = 200 µm. 4 – 7. Sphaerogypsina globulus (Reuss, 1848). 4 – 5. QM # G 466002 from WL 12 lateral views. Scale bar for 5 = 200 µm. 6 – 7. QM # G 466006 from WL 15 lateral views. 8 – 10. Amphistegina lessonii d’Orbigny, 1826. 8 – 9. QM # G 466052 from T 1 – 6, spiral view (8) and peripheral view (9). 10. QM # G 465877 from CHANNEL, umbilical view. Scale bar = 200 µm. 11 – 12. Amphistegina lobifera Larsen, 1976. 11. QM # G 465954 from CHANNEL, spiral view. Scale bar = 200 µm. 12. QM # G 466129 from CHANNEL, umbilical view. Scale bar = 200 µm. 13 – 14. Amphistegina radiata Fichtel & Moll, 1798 from CHANNEL. 13. QM # G 465879 spiral view. Scale bar 200 µm. 14. QM # G 465876 spiral view. Scale bar 500 µm. 15 – 17. Haynesina depressula (Walker & Jacob, 1798). 15 – 16. QM # G 465815 from OTI 51, lateral (15) and peripheral (16) views. 17. QM # G 465945 from OTI 33, lateral view. 18 – 21. Neorotalia calcar (d’Orbigny, 1839). 18 – 19. QM # G 465801 from T 2 – 3, spiral (18), peripheral (19) and umbilical (20) views. 21. QM # G 466110 from ST / HW 4, umbilical view.

FIGURE 24. (Unless otherwise specified all scale bars = 100 µm). 1 – 4. Baculogypsina sphaerulata (Parker & Jones, 1860). 1 – 2. QM # G 465795 from T 2 – 3 lateral (1) and peripheral (2) views. Scale bar = 200 µm. 3. QM # G 465798 from T 2 – 3 lateral view. Scale bar = 500 µm. 4. QM # G 466108 from ST / HW 6 lateral view. Scale bar = 500 µm. 5 – 14. Calcarina capricornia n. sp.. 5. QM # G 466107 from ST / HW 4, spiral view. Scale bar = 200 µm. 6 – 7. QM # G 465799 from T 2 – 3 spiral (6) and umbilical (7) views. Scale bar = 200 µm. 8 – 9. QM # G 465800 from T 2 – 3 umbilical (8) and peripheral (9) views. Scale bar for 8 = 500 µm. Scale bar for 9 = 200 µm. 10. QM # G 465783 from ST / HW 10, spiral view. Scale bar = 200 µm. 11 – 12. QM # G 466041 from T 2 – 7, spiral (11) and peripheral (12) views. Scale bar for 11 = 500 µm. Scale bar for 12 = 200 µm. 13 – 14. QM # G 466047 from T 1 – 6, umbilical (13) and peripheral (14) views. Scale bar = 500 µm. 15 – 18. Calcarina mayori Cushman 1924. 15 – 16. QM # G 466048 from T 1 – 6, spiral (15) and periperhal (16) views. Scale bar = 200 µm. 17. QM # G 466050 from T 1 – 6, spiral view. Scale bar = 200 µm. 18. QM # G 466049 from T 1 – 6, umbilical view. Scale bar = 200 µm. 19 – 20. Cribroelphidium cf. C. excavatum (Terquem, 1875), QM # G 465785 from ST / HW 2. 19. Lateral view. 20. Peripheral view.