Characodoma erinaceum, Martino & Rosso & Taylor & Chiu & Fujita & Kitamura & Yasuhara, 2025

Martino, Emanuela Di, Rosso, Antonietta, Taylor, Paul D., Chiu, Ruby W. T., Fujita, Kazuhiko, Kitamura, Akihisa & Yasuhara, Moriaki, 2025, Unveiling the cheilostome bryozoan fauna of Daidokutsu submarine cave (Okinawa, Japan) over the last 7,000 years, Palaeontologia Electronica (a 7) 28 (1), pp. 1-125 : 87-89

publication ID

https://doi.org/10.26879/1433

publication LSID

lsid:zoobank.org:pub:6E7554EF-C09B-4860-AC2A-FA1A6FD53B03

persistent identifier

https://treatment.plazi.org/id/373A87F4-2D26-D913-FE7D-F894DC43F9B6

treatment provided by

Felipe

scientific name

Characodoma erinaceum
status

sp. nov.

Characodoma erinaceum sp. nov.

Di Martino, Rosso, and Taylor

Figure 51 View FIGURE 51

zoobank.org/ 8E740FD0-F384-42D0-8B23-B461004FC248

Type material. Holotype PMC. B69. 29.7.2024 a, sample 19183 ( Figure 51E, G View FIGURE 51 ); paratype PMC. B69. 29.7.2024 b1, sample 19025 ( Figure 51A–B View FIGURE 51 ); paratype PMC. B69. 29.7.2024 b2, sample 19041 ( Figure 51C–D View FIGURE 51 ); paratype PMC. B69. 29.7.2024 b3, sample 19068 ( Figure 51F View FIGURE 51 ); paratype PMC. B69. 29.7.2024 b4, sample 19228 ( Figure 51H View FIGURE 51 ); Core 19, Daidokutsu cave, Okinawa, Japan, Holocene.

Etymology. Latin, meaning hedgehog, referring to the spiny appearance of its frontal shield.

Diagnosis. Characodoma with both encrusting and erect colony growth phases, hexagonal autozooids with rather smooth frontal shield becoming spinous during ontogeny, imperforate except for two subcircular to slit-like marginal areolae at zooidal distolateral corners; orifice keyhole-shaped with small triangular condyles pointing proximally and shallow bowl-shaped sinus; avicularia rare, single, budded from one of the distolateral areolae, drop-shaped; rostrum rounded triangular directed distolaterally; crossbar complete; ovicell resting on the frontal shield of the distal zooid at a certain distance from distal margin of orifice of maternal zooid, with large rounded triangular opening; ooecium smooth with spiny tubercles as in the frontal shield.

Description. Colony with both encrusting and erect growth phases; erect portion tubular or flat and bilamellar. Autozooids distinct, separated by shallow grooves and sometimes raised sutures, arranged quincuncially, hexagonal, longer than wide (mean ZL/ZW 1.27). Frontal shield smooth, developing spiny tubercles, up to 25 µm long, during ontogeny; tubercles aligned to form a collar proximally to orifice and additional tubercles developing concentrically to the collar or radially, usually occupying the central part of the frontal shield, leaving the proximal third bare; frontal shield appearing radially striated when tubercles are not yet developed; imperforate, with only 1–2 subcircular, slit-like or reniform marginal areolae, 20–30 µm long, placed at the distolateral corners of zooids, budding adventitious avicularia; occasionally a single areola present proximally. Orifice keyhole-shaped, with a horseshoe-shaped anter separated from a narrower, bowl-shaped sinus by two small, acutely triangular condyles pointing proximally, oral spines absent. Avicularium rarely present, placed on a raised cystid at zooidal lateral corner on either side, drop-shaped; rostrum rounded triangular, directed distolaterally; crossbar complete. Ovicell resting on the frontal shield of the distal zooid, not covering the distal orificial margin of the maternal zooid but at a certain distance from it (15–20 µm), globular, with large rounded triangular opening (60 µm long by 90 µm wide); ooecium smooth, developing spiny tubercles like the frontal shield. Avicularia occasionally showing evidence of intramural budding.

Measurements (µm). ZL 300±33, 236–361 (3, 20); ZW 235±34, 186–305 (3, 20); OL 111±8, 99–127 (3, 15); OW 103±7, 91–117 (3, 15); AvL 101±13, 83– 120 (2, 12); AvW 64±5, 57–73 (2, 12); OvL 151±9, 140–164 (2, 6); OvW 190±18, 161–205 (2, 6).

Remarks. Most species of Characodoma have a granular, imperforate frontal shield with a row of conspicuous marginal pores. However, a few species have a rather smooth frontal shield with sparse tubercles and only one or two marginal areolae from which the avicularia are budded, as in this new species. Among these, the Indo-Pacific Characodoma longitudinale (Harmer, 1957) differs by having rounded tubercles (spiny in the Japanese species), and in the shape of the sinus, which is arrow-shaped in C. longitudinale but bowl-shaped in the new species (see also Di Martino et al., 2019, figure 9D–G). Additionally, the avicularia in C. longitudinale are smaller and rounded, whereas they are larger and triangular in C. erinaceum sp. nov. The Miocene species C. excubans ( Waters, 1881) and C. rotundum ( Waters, 1881) are the most similar, having a frontal shield that becomes spinose during ontogeny and both encrusting and erect colony growth phases (Cook and Bock, 1996). They differ in the position, direction and shape of avicularia: the former species has paired latero-oral avicularia directed proximolaterally outwards in addition to frontal spatulate avicularia, while the latter species has oval avicularia pointing to the orifice. ‘Characodoma’ latisinuatum Harmer, 1957 has a similar spiny appearance but is doubtfully placed in Characodoma because of its pseudoporous frontal shield. Based on the original drawing, the Japanese species Cleidochasma inermis Ortmann (1890) and C. japonica Ortmann (1890) seem to fit better in Plesiocleidochasma than in Characodoma .

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