Foveolaria retiformis Harmer, 1926

Foveolaria retiformis Harmer, 1926 View in CoL

Figure 8 View FIGURE 8

v. 1926 Foveolaria retiformis Harmer , p. 247, pl. 14, figs. 21–23.

v. 2010 Foveolaria retiformis Harmer ; Hirose, p.

37, pl. 62.

Figured material. PMC EDM-Collection J.H.B.124a, sample 19072 ( Figure 8A–C View FIGURE 8 ), sample 19232 ( Figure 8D–E View FIGURE 8 ), and sample 19227 ( Figure 8F View FIGURE 8 ); Core 19, Daidokutsu cave, Okinawa, Japan, Holocene.

Description. Colony erect with bi- tri- or quadriserial, unilaminar branches, flat to slightly convex, straight or slightly curved, c. 500 µm wide. Autozooids distinct, separated by fine furrows as well as the raised rim of the cryptocyst surrounding the opesia, rectangular to club-shaped, elongate (mean ZL/ZW 2.23), arranged alternately in longitudinal rows. Gymnocyst smooth, extensive proximally, thin laterally and distally; cryptocyst wrinkled, moderately wide, uniformly encircling the opesia, raised marginally and steeply sloping into the opesia. Opesia oval, occupying most of the frontal surface (mean OpL/ZL 0.67); muscle scars visible through the opesia at distolateral corners; spines absent. Avicularia adventitious, lodged on proximal gymnocyst, touching the proximal cryptocystal rim, pear-shaped, transversely oriented; rostrum raised, narrow, truncated, channelled, curved and serrated, directed laterally upwardly, resting on the distal cryptocystal rim of the neighbouring autozooid; two faint condyles and oval opesia. Ovicells hyperstomial, globular; ooecium smooth having a slightly raised and bent proximal margin; endooecium mostly exposed except for a distal band of calcified ectooecium, 26–40 µm wide. Dorsal side flat or slightly concave, smooth, with central median line and divergent wrinkles; a pair of circular rootlet pores consistently present at the level of proximal and distal ends of zooids external to the branch.

Measurements (µm). ZL 559±40, 515–627 (2, 9); ZW 251±9, 236–261 (2, 9); CryL 53±13, 36–74 (2, 8); GymL 165±15, 146–184 (2, 8); OpL 372±24, 342–415 (2, 12); OpW 230±16, 207–257 (2, 12); AvL 177±13, 156–200 (2, 8); AvW 93±6, 86–106 (2, 8); OvL 254±14, 244–264 (1, 2); OvW 288±11, 280–296 (1, 2).

Remarks. The available fragments do not provide sufficient evidence to confirm the reticulate colony shape characteristic of this species. However, all other observed characters align with the original description of the species by Harmer (1926) from Sulu Archipelago in the Philippines.