Paragigantopora echinata, Martino & Rosso & Taylor & Chiu & Fujita & Kitamura & Yasuhara, 2025

Paragigantopora echinata sp. nov. Di Martino, Rosso and Taylor

Figure 43 View FIGURE 43

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Type material. Holotype PMC. B64. 29.7.2024 a, sample 19140; Core 19, Daidokutsu cave, Okinawa, Japan, Holocene.

Etymology. Latin, meaning thorny, referring to the frontal shield tubercles giving a spinose appearance to the zooids.

Diagnosis. As for Paragigantopora gen. nov.

Description. Colony erect with cylindrical branches. Autozooids distinct, separated by narrow furrows, arranged in alternating longitudinal series, rhomboidal, elongate (mean ZL/ZW 1.84). Frontal shield flat, densely covered with evenly distributed tubercles, centrally imperforate; tubercles pointed, occasionally bifurcated, protruding from frontal shield surface by 25–35 µm, lending it a prickly appearance; narrowly elliptical marginal areolae, 35–55 µm long by 15–26 µm wide, distinguishable laterally, one on each side; a few (≤10), circular, smaller areolae, 7–12 µm in diameter, extending onto the proximal portion of the shield. Primary orifice concealed beneath a raised, tubular peristome extending upwards and outwards for approximately 170–250 µm from the branch axis, at an angle of c. 35º; peristomial bridge measuring 90–170 µm in width, lacking tubercles, forming a large, semicircular to reniform spiramen proximally, 100–110 µm long by 165–200 µm wide; secondary orifice elliptical, 100–190 µm long by 130–200 µm wide. Avicularia adventitious, single or paired, placed transversely to the elongation of the zooid and laterally on the peristome at the level of the proximal margin of secondary orifice (or distal margin of peristomial bridge), oval, with rounded rostrum directed laterally and inwards with complete crossbar. Ooecium partially immersed within the frontal shield of the distal zooid, opening into the peristome over the primary orifice; surface nodular and imperforate with a few (approximately five), small, circular marginal areolae visible on the periphery, 5–7 µm in diameter.

Measurements (µm). ZL 830±51, 770–875 (1, 4); ZW 450±43, 396–487 (1, 4); AvL 89±8, 75–100 (1, 7); AvW 60±9, 50–72 (1, 7); OvL 158 (1, 1); OvW 260 (1, 1).

Remarks. Paragigantopora echinata gen. et sp. nov. differs from the sole other species we propose including in this newly established genus, P. grandis comb. nov., primarily in the morphology and orientation of its peristomial avicularia. In P. grandis comb. nov., these avicularia have an acute rostrum curving obliquely proximally onto the peristomial bridge. Additionally, P. grandis comb. nov. has a more prominent ooecium. Although some partial similarities have been noted with other species currently assigned to Gigantopora , the differences remain more pronounced, as detailed above in the Remarks section of the new genus.