Adeona odontoti Martha & Scholz, 2025, sp. nov.

Adeona odontoti sp. nov. urn:lsid:zoobank.org:act: 80E09C57-8702-4AC5-B32B-A06009C6992B (Fig. 7.1–4) Material examined. Holotype: SMF 40782 (St. 283 KU; Fig. 7.1–4). Etymology. Derived from Modern Greek οδοντωτή (‘dentate’), referring to the denticles associated with the spiramen. Description. Colonies rigidly erect, multiserial, bilamellar, dichotomously branching (Fig. 7.1). Autozooids arranged quincuncially, separated by thin, calcified threads. Pore chambers, ancestrula and early astogeny not observed. Autozooids subhexagonal, 358–491 μm (ẋ = 408 ± 39 µm; CV = 9; N = 20 on 1 specimen) long by 182–272 μm (ẋ = 223 ± 19 µm; CV = 9; N = 20 on 1 specimen) wide (Fig. 7.2). Frontal shield moderately convex, granular, pierced by one row of evenly spaced, circular areolar pores at the margins. Orifice semicircular with well-rounded proximolateral margins, 66–94 μm (ẋ = 80 ± 8 µm; CV = 10; N = 20 on 1 specimen) long by 86–129 μm (ẋ = 103 ± 11 µm; CV = 11; N = 20 on 1 specimen) wide (Fig. 7.3). Spiramina non-projecting, single; outer opening located medially, inside depression, transversely elliptical, bearing three denticles at distal and proximolateral margins, 27–63 μm (ẋ = 39 ± 10 µm; CV = 25; N = 20 on 1 specimen) long by 33–60 μm (ẋ = 42 ± 7 µm; CV = 17; N = 20 on 1 specimen) wide (Fig. 7.3); frontal shield sloping into spiraminal depression from all sides. Spine bases lacking. Ovicells not observed. Avicularia monomorphic, adventitious, suboral, triangular, bilaterally symmetrical, 79–127 μm (ẋ = 100 ± 10 µm; CV = 10; N = 20 on 1 specimen) long by 58–75 μm (ẋ = 65 ± 5 µm; CV = 7; N = 20 on 1 specimen) wide (Fig. 7.4). Avicularian aperture central, transversely elliptical; crossbar absent. Rostrum acutely triangular, directed laterally or slightly proximolaterally or distolaterally. Kenozooids not observed. Remarks. Amui (2005) described three adeonid species of the genus Adeonella Busk, 1884, from the Bab-el-Mandeb Strait and the Gulf of Aden. All three species possess a porous frontal shield, whereas Adeona odontoti sp. nov. is distinguished by having a single row of evenly spaced, circular areolar pores along the margin of the frontal shield (Fig. 7.2). Additionally, the new species features a monoporous, denticulate spiramen (Fig. 7.3), structures not observed in the previously described Adeonella species from the region. Adeona odontoti sp. nov. is the first species from the western Indian Ocean assignable to the genus Adeona. The closest known relatives of Adeona odontoti sp. nov. appear to be Adeona arculifera Canu & Bassler, 1929 and Adeona articulata Canu & Bassler, 1929, both originally described from the southern Sulu Sea. In Adeona arculifera, avicularia are distolaterally oriented and indent the orifice. Colonies of Adeona articulata are articulated but also exhibit skeletal branching; their avicularia are large, distolaterally directed, and may possess a trifoliate aperture (Di Martino et al. 2019). In contrast, avicularia in Adeona odontoti sp. nov. are oriented laterally, sometimes curving slightly upward or downward, and have an elliptical aperture (Fig. 7.4).