Planispirillina denticulogranulata ( Chapman, 1907 )

Lee, Somin & Lee, Fabrizio Frontalini and Wonchoel, 2023, A report of three newly recorded benthic foraminiferal species from Korea, Journal of Species Research 12 (1), pp. 48-54 : 50

1. Planispirillina denticulogranulata ( Chapman, 1907)

( Plate 1 , figs. 1, 2)

Spirillina denticulogranulata Chapman, 1907, p. 133 , pl. 10, fig. 6a - c; Hayward et al., 1999, pl. 92, pl. 3, figs. 5, 6.

Planispirillina denticulogranulata : Parker, 2009, p. 74, fig. 53a - j.

Material examined. Sungsan Seom-yeo diving point, Seogwipo Jeju Island, 33°27′21.54″N 126°56′3.06″E, 2 August 2020, by SCUBA diving, collected by Heerin Kim, Jisu Yeom and Wonchoel Lee. MABIK ID: MABIK PR00044173, MABIK PR00044174 .

Diagnosis. Test discoidal, consisting of a globular proloculus and tubular, undivided planispirally coiled second chamber. Periphery not strongly acute, thickened at spiral side margin. Spiral side of test evolute, three to four whorls visible. Spiral suture limbate, prominently raised. Sutural border ornamented with numerous depressions or short grooves perpendicular to the suture. Opposite side flattened to slightly concave, suture unclear due to numerous pustules covering almost entire surface. Wall calcareous perforate, aperture simple opening at the end of tubular chamber. Test diameter about 340 μm, thickness about 87 μm.

Remarks. The type species of the genus Planispirillina Bermúdez, 1952 is P. papillosa ( Cushman, 1915) , and there are total of 13 extant, accepted species belonging to the genus. Among those species, P. papillosa and P. tuberculatolimbata ( Chapman, 1900) are most similar to P. denticulogranulata ( Chapman, 1907) in having papillose ventral side and prominent, limbate spiral suture. However, based on the original descriptions ( Chapman, 1900; 1907; Cushman, 1915), P. denticulogranulata is distinguished from the other species by the presence of ornamentation on the edge of spiral suture. Additionally, the borders of spiral suture in P. papillosa are almost wavy ( Cushman, 1915), whereas in P. denticulogranulata , the waviness of sutural borders is not clearly observed. On the other hand, P. papillosa and P. tuberculatolimbata are morphologically very similar, so they were once recorded as synonym by Cheng and Zheng (1978). However, according to Hatta and Ujiié (1992), test wall of the spiral side in P. papillosa is more finely perforate, as can be seen in the original figure ( Cushman, 1915) and the re-drawing by Loeblich and Tappan (1964).

Planispirillina denticulogranulata has been reported in Australia ( Chapman, 1907; Parker, 2009), and New Zealand ( Hayward et al., 1999). According to Parker (2009), the spiral suture grooves become stronger in the later whorl, forming a coarse reticulum. The specimens reported by Hayward et al. (1999) have slightly weaker ridges than those of Parker (2009) but have also stronger spiral suture grooves on the later whorl than the first. In Korean specimens, the grooves appear to be weaker than the others, however the ridges seem to be projecting in from the outer margin of suture, so in this respect it matches the type illustration well. Furthermore, coarse ridges on the later whorls as the other specimens can also be observed, which are partially obscured by debris and diatom particles.

Distribution. Korea, Australia, and New Zealand.

Class Globothalamea Pawlowski, Holzmann & Tyszka, 2013

Order Rotaliida Delage & Hérouard, 1896

Family Ammoniidae Saidova, 1981

Genus Hemirotalia Lei & Li, 2016

Figures

Plate 1. Photomicrograph and SEM image of the newly recorded species. All scales are 100 μm. 1, 2. Planispirillina denticulogranulata (Chapman, 1907); 1. (a-h) MABIK PR00044173; 1a. Ventral side view, SEM image; 1b. Lateral side view, SEM image; 1c. Spiral side view, SEM image; 1d. Ventral side view, photomicrograph; 1e. Spiral side view, photomicrograph; 1f-h. Close-up of spiral suture ornamentation, SEM image. 2. (a, b) MABIK PR00044174; 2a. Spiral side view, SEM image; 2b. Close-up of spiral suture ornamentation, SEM image.