Pileolina Bermúdez 1952

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 83-84

Pileolina Bermúdez 1952

Pileolina ? minogasaformis (Ujiié, in Hatta & Ujiié 1992a) ( Fig. 20 :6–9)

1884 Discorbina tabernacularis Brady , pl. 89, fig. 7.

1960 Pileolina ? tabernacularis (Brady) ; Barker, p. 184, pl. 89, fig. 7.

1991 Glabratella australiensis (Heron-Allen & Earland) ; Van Marle, p. 183, pl. 19, figs 1–4. 1992 a Discorbinoides minogasaformis Ujiié ; Hatta & Ujiié, p. 185, pl. 34, figs 2, 3. 1994 Discorbinoides minogasiformis Ujiié ; Loeblich & Tappan, p. 141, pl. 291, figs 1–10. 1994 Glabratella tabernacularis (Brady) ; Jones, p. 95, pl. 89, fig. 7.

1995 Glabratella patelliformis (Brady) ; Yassini & Jones, p. 161, figs 735, 738. 2009 Discorbinoides ? minogasiformis (Ujiié) ; Parker, p. 562, fig. 398.

2012 Pileolina minogasiformis (Ujiié) ; Debenay, p. 207.

Description. See Hatta & Ujiié (1992a, 185, pl. 34, figs 2, 3) and Parker (2009, p. 562, fig. 398).

Remarks. Pileolina ? minogasaformis ( Ujiié 1992a) has a trochspiral, planocovex test. The spiral side has an acute apex and the chamber whorls have perforate walls interspersed with imperforate, limbate sutures. Both the spiral and umbilical side possess an ornament of straight, radiating grooves, but is more distinct on the umbilical side. The aperture is large, terminal, extraumbilical and filled with pustules ( Fig. 20 :6–9).

It is unclear as to which is both the correct genus assignment for this species as well as the correct spelling. Several sources ( Loeblich & Tappan 1994; Parker 2009; Debenay 2012) use one spelling ( minogasiformis instead of minogasaformis ) and others apply that of Ujiié (1992a), which is here, presumed correct. Without the provision of justification, “ minogasiformis ” is deemed “incorrect subsequent spellings” according to article 33c of the ICZN (2000). Parker (2009) has outlined the significant confusion surrounding the validity of Discorbinoides , especially its close similarity to Pileolina Bermúdez 1952 . Loeblich & Tappan (1987) considered Pileolina of uncertain status due to loss of the original type material. In contrast, Hayward et al. (1999) and others ( Hornibrook & Vella 1954; Vella 1957) consider the genus to be valid due to the work of Heron-Allen & Earland (1932), which was based on examinations of d’Orbigny’s (1839) original type material. Heron-Allen & Earland (1932) suggested that the type species of Pileolina , Valvulina pileolus d’Orbigny 1939 was conspecific with Discorbina pulvinata Brady 1884 which would place this species in Glabratella Dorreen 1948 or Conorbella Hofker 1951 ( Parker, 2009) . The World Foraminifera Database ( Hayward 2014) considers Discorbinoides a subjective junior synonym and therefore invalid. Pileolina ? minogasaformis has thus been placed under several different genera.

Morphological variations displayed by specimens of P. minogasaformis include differences in apex definition, coarseness of spiral side perforations and definition of spiral side imperforate sutures, resulting in two morphotypes. The apex of P. minogasaformis varies from a sharp conical point ( Brady 1884; Hatta & Ujiié 1992a; Loeblich & Tappan 1994; Parker 2009; Debenay 2012) to a blunt, round apex as in the CG specimens ( Brady 1884; Van Marle 1991; Hatta & Ujiié 1992a; Loeblich & Tappan 1994; Yassini & Jones 1995; Parker 2009). The perforations on the spiral side can be large, coarsely developed and closely spaced, interspersed with clear, thick, imperforate sutures ( Van Marle 1991; Hatta & Ujiié 1992a; Loeblich & Tappan 1994; Yassini & Jones 1995; Parker 2009; Debenay 2012), or fine, closely spaced, scattered perforations interspersed by poorly defined, thin imperforate sutures ( Brady 1884; Hatta & Ujiié 1992a; Loeblich & Tappan 1994; Parker 2009). Like the CG, most locations where P. minogasaformis occurs include both morphotypes ( Fig. 20 :6–9).

The original specimens of Discorbina patelliformis Brady 1884 from the Challenger expedition were collected from the Admiralty Islands at a depth of 31 m. Van Marle (1991) found specimens in Late Miocene to Early Pliocene—Quaternary sediments from eastern Indonesia in association with upper to middle bathyal species. Hatta & Ujiié (1992a) established D. minogasaformis from specimens collected from coral seas between Ishigaki and Iriomote Islands within the southern Ryukyu Island Arc . The distribution since has been reported from the Indo- Pacific ( Bathurst Island from 62 m, Darwin from 20 m, Bonaparte Gulf from 24 m—Loeblich & Tappan 1994; open estuaries, sheltered oceanic embayments, intertidal zone of the inner shelf, inlet channels of coastal lagoons, southeastern Australia—Yassini & Jones 1995; Ningaloo Reef—Parker 2009; New Caledonia southwestern lagoon from 40 m—Debenay 2012).

Distribution within study area. Pileolina ? minogasaformis was only collected from One Tree and Wistari Reefs. Greatest abundance was at site 54 in One Tree Lagoon 1, with six specimens collected. The majority of the remaining specimens were also collected from One Tree Reef. Only three sites at Wistari yielded any specimens.

Figures

FIGURE 20. (Unless otherwise specified all scale bars = 100 µm). 1 – 3. Neoconorbina? sp. 1, from T 1 – 4. 1 – 2. QM # G 466023 from T 1 – 4, spiral view (1) and close-up spiral (2) view. Scale bar for 2 = 50 µm. 3. QM # G 466082 from T 1 – 2 umbilical view, scale bar = 50 µm. 4 – 5. Buliminoides williamsoniana (Brady, 1881), QM # G 465931 from WL 21. 4. Lateral view. 5. Peripheral view. 6 – 9. Pileolina? minogasaformis Ujiié, 1992. 6 – 7. QM # G 465970 from OTI 48, spiral (6) and peripheral (7) views. Scale bar for 7 = 50 µm. 8 – 9. QM # G 466016 from OTI 53, peripheral (8) and umbilical (9) views. Scale bar = 50 µm. 10 – 14. Cibicidoides cf. C. basilanensis McCulloch, 1977. 10. QM # G 466004 from OTI 53. Spiral view, scale bar = 50 µm. 11 – 12. QM # G 466005 from OTI 53, peripheral (11) and umbilical (12) views. Scale bar = 50 µm. 1 3 – 14. QM # G 466139 from ST / HW 10, peripheral (13) and umbilical (14) views. Scale bar = 50 µm. 15 – 17. Epistomaroides polystomelloides (Parker & Jones, 1865), QM # G 466009 from OTI 48. Scale bar = 200 µm. 15. Spiral view. 16. Umbilical view. 17. Peripheral view. 18 – 20. Epistomaroides punctatus (Said, 1949) 18 – 19. QM # G 465796 from T 2 – 3. 18. Spiral view. 19. Peripheral view. 20. QM # G 466014 from T 1 – 10, peripheral / spiral view.