Gigantopora sp. 1

Gigantopora sp. 1

Figure 42 View FIGURE 42

Figured material. PMC EDM-Collection J.H.B.139a, sample 19140; Core 19, Daidokutsu cave, Okinawa, Japan, Holocene.

Description. Colony encrusting, multiserial, unilaminar. Autozooids oval to rhomboidal, longer than wide (ZL/ZW 1.40). Frontal shield bearing predominantly rounded tubercles and a few more prominent, presumably pointed processes, with some circular pores difficult to distinguish as either areolae or frontal pseudopores. Peristome tubular forming a broad, nearly smooth bridge, 110–190 µm wide, and a large elliptical to eight-shaped spiramen, with flared margin, 80–105 µm long by 150– 250 µm wide. Secondary orifice rounded, 170 µm long by 180 µm wide. Avicularia present or absent, adventitious on the side of peristome, directed laterally inwards; rostrum raised, acutely triangular, with complete crossbar.

Measurements (µm). ZL 724 (1, 1); ZW 517 (1, 1); AvL 174 (1, 1); AvW 77 (1, 1).

Remarks. The specimen bears a striking resemblance to species of Gigantopora . However, its poor preservation prevents the observation of certain morphological features, such as the potential perforation of the frontal shield, and precise morphological measurements of most traits. Additionally, the small size of the specimen and the absence of ovicells impede thorough characterization and examination of intracolonial variability. The shape of the avicularia, with an acutely triangular rostrum, is typical of several Gigantopora species, including the widely distributed Indo-Pacific G. pupa (Jullien, 1903) . Nonetheless, the smoothly tuberculate surface of the frontal shield, adorned with rounded rather than the more typical pointed tubercles, and the completely smooth texture of the peristomial bridge are less common.