Adelosina

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 27

Adelosina sp. cf. A. pulchella d’Orbigny 1826 ( Fig. 6 :8–13)

Description. Test broad, approximately as wide as tall, outermost chambers irregular, quadratic and carinate with quinqueloculine arrangement. Chambers inflated, slightly convex from carina. Oral and aboral ends rounded. Roughened wall texture with weak, shallow, longitudinal striae. Aperture terminal on short neck with irregular oval outline, bordered by a thin lip. Dentition consists of a stout, short tooth. Additional nub-like teeth located either side of central tooth, on apertural rim, approximately perpendicular to main central tooth ( Fig. 6 :8–13).

Remarks. As the original test description for Quinqueloculina pulchella d’Orbigny 1826 has been lost ( Ellis & Messina 1940), it is difficult to identify this species with confidence. However, the type figure illustrations by Parker et al. (1871) show an inflated, rounded test with deep, thick longitudinal striae. In contrast, the specimens collected during the Challenger Expedition ( Brady 1884, pl. 6, fig. 13) display the diagnostic test shape, longitudinal striae and aperture of the species. Collected specimens are similar to Brady’s illustrations (1884, pl. 6, fig. 13) and also exhibit the taxon’s distinct test shape, aperture and longitudinal striae. Jones (1994) later reassigned the Challenger specimens to Adelosina due to the terminal placement of the aperture. Specimens collected from the CG vary in length of neck, regularity of their oval-shaped aperture and size of dentition/nubs (Compare Fig. 6 : 8–10 to 11–13).

The type specimens of this species were collected from the Atlantic Ocean along the coasts of France and the Mediterranean ( d'Orbigny 1826). Brady’s (1884) specimens were also from the Atlantic , along the west coast of Scotland and Skye from depths of 82 – 110 m. This species is rarely reported from reef environments making complete synonymy difficult. Cheng & Zheng (1978) assigned material from the Xisha Islands to Triloculina costifera Terquem 1878 which closely resembles A. pulchella in having an inflated test with convex, carinate margins and rounded oral and aboral ends. However , the triloculine, as opposed to quinqueloculine chamber arrangement and oval aperture with a single tooth, sets this taxon apart. Specimens published by Haig (1988) from the Papuan Lagoon as Quinquloculina cf. Q. collumnosa Cushman 1922 are similar to A. pulchella in having a warped carinate test with fine longitudinal striae. But they differ in that the test is more compressed and the circular aperture sits atop a long, slender neck.

Distribution within study area. Adelosina sp. cf. A. pulchella was found in low abundance with no more than five specimens per sample from site 50 in Heron Lagoon. This taxon was absent from Sykes Reef.

Figures

FIGURE 6. (Unless otherwise specified all scale bars = 100 µm). 1 – 7. Adelosina carinatastriata Wiesner, 1923. 1 – 2. QM # G 466097 from WL 21, lateral view (1) and oral (2) views. 3 – 5. QM # G 465820 from OTI 36, lateral (3), peripheral (4) and oral views (5). 6 – 7. QM # G 465919 from WL 7, lateral (6) and oral (7) views. 8 – 13. Adelosina cf. A. pulchella (d’Orbigny, 1826). 8 – 10. QM # G 466087 from ST / HW 10 lateral view (8), oral view (9) and peripheral view (10). 11 – 13. QM # G 466067 from HL 40 lateral views (11, 12) and oral view (13). 14 – 17. Spiroloculina angulata Cushman, 1917. 14 – 15. QM # G 465824 from OTI 36 lateral view (14) and oral view (15). Scale bars = 50 µm. 16 – 17. QM # G 466066 from T 3 – 6 lateral (16) and oral (17) views. 18 – 19. Spiroloculina corrugata Cushman & Todd 1944, QM # G 466059 from OTI 39. 18. Lateral view. 19. Peripheral view. 20 – 21. Spiroloculina cf. S. depressa d’Orbigny, 1826, QM # G 465893 from ST / HW 8. 20. Lateral view 21. Oral view.