Exechonella juliae, Martino & Rosso & Taylor & Chiu & Fujita & Kitamura & Yasuhara, 2025

Exechonella juliae sp. nov.

Di Martino, Rosso and Taylor

Figure 23 View FIGURE 23

zoobank.org/ 9C66D176-4D5D-4DDD-92E7-308A1E367398

Type material. Holotype PMC. B54. 29.7.2024 a, sample 19014 ( Figure 23D–E View FIGURE 23 ); paratype PMC. B54. 29.7.2024 b1, sample 19059 ( Figure 23A–B View FIGURE 23 ); paratype PMC. B54. 29.7.2024 b2, sample 19015 ( Figure 23C View FIGURE 23 ); paratype PMC. B54. 29.7.2024 b3, sample 19042 ( Figure 23F View FIGURE 23 ); Core 19, Daidokutsu cave, Okinawa, Japan, Holocene.

Etymology. Named in honour of Dr Julia Cáceres-Chamizo, recognizing her significant contribution to the study of Exechonella and her efforts to disentangle its species complexes.

Diagnosis. Exechonella of the ampullacea -complex with numerous, medium-sized, rounded foramina with narrow rims, limited number of flat frontal projections, and tubular peristome with flared and jagged rim.

Description. Colony encrusting, multiserial, unilaminar. Autozooids distinct, separated by deep grooves, bottle-shaped, longer than wide (mean ZL/ZW 1.34). Frontal shield convex, pustulose, evenly and densely perforated by 32–44 medium-sized, rounded foramina with a slightly raised, narrow rim; one to three foramina per zooid bearing a flat, blunt or pointed, frontal projection reaching up to 50–90 µm in length; shape of foramina modified to reniform or semicircular when bearing the frontal projection. Primary orifice oval, concealed by a long, tubular, distally tapering peristome; condyles not seen. Peristome pustulose externally, with pustules 20–35 µm in diameter, longitudinally striated on its internal surface with a distance between striations of 25–38 µm, imperforate, facing obliquely frontally, forming an angle of 15–70º in respect to the colony surface; peristome margin slightly flared and jagged; secondary orifice circular to elliptical. Avicularia absent. Kenozooids not observed.

Measurements (µm). ZL 813±68, 707–943 (5, 20); ZW 606±69, 519–791 (5, 20); OL (secondary) 220±30, 172–257 (3, 10); OW (secondary) 227±33, 155–262 (3, 10); PeL 493±89, 301–652 (5, 20); FoN 38±6, 32–44 (2, 5); FoD 41±5, 31–51 (5, 20).

Remarks. This species belongs to the Exechonella ampullacea -complex, which is characterized by bottle-like zooids, long tubular peristomes, numerous mid-sized foramina and the absence of avicularia (Cáceres-Chamizo et al., 2017). The Japanese species closely resembles E. safagaensis Cáceres-Chamizo, Sanner, Tilbrook and Ostrovsky, 2017 from the Red Sea, and E. variperforata Cáceres-Chamizo, Sanner, Tilbrook and Ostrovsky, 2017 from the Great Barrier Reef, sharing some traits with each. It shares the length of autozooids and the number of foramina with E. safagaensis but differs in having smaller foramina with narrower rims, fewer and flatter frontal projections, longer peristomes, and wider autozooids. With E. variperforata , it shares the flat shape of the frontal projections and the narrower rims of the foramina but differs in having more numerous, smaller foramina, fewer frontal projections, and longer, narrower peristomes.