Thalamoporella annmargretae Martha & Scholz, 2025, nom. nov.

Thalamoporella annmargretae nom. nov. urn:lsid:zoobank.org:act: 2EA86352-576E-4056-B4FF-13D4EF9FDAA8 (Fig. 2.1–6) Thalamoporella arabiensis Amui & Kaselowsky, 2006: 18, figs 23, 24. Non Thalamoporella arabiensis Guha & Gopikrishna, 2004: 18, figs 13–15; Sonar et al. 2022: 258, fig. 7A–C. Material examined. Lectotype (here designated): SMF 1900 (St. 236 KD; Fig. 2.2). Paralectotype: SMF 1900 (St. 236 KD; Fig. 2.6, and three other specimens of syntype series). Paratypes: SMF 1815 (St. 236 KD; Fig. 2.1, 2.3–5), SMF 1867 (St. 236 KD), SMF 1901 (St. 236 KD), SMF 1902 (St. 236 KD), SMF 1903 (St. 236 KD). Etymology. Named in honour of Ann-Margret Amui-Vedel (born 1977), in recognition of her contributions to the study of bryozoan fauna from the Gulf of Aden. Description. Colonies rigidly erect, multiserial, bilamellar, dichotomously branching (Fig. 2.1–3). Autozooids arranged in alternating series, separated by thin furrows between raised margins. Pore chambers, ancestrula and early astogeny not observed. Autozooids longitudinally rectangular with convex distal margin and concave proximal margin, 699–950 μm (ẋ = 827 ± 63 µm; CV = 8; N = 49 on 5 specimens) long by 250–429 μm (ẋ = 337 ± 45 µm; CV = 13; N = 49 on 5 specimens) wide (Fig. 2.4). Gymnocyst not visible. Cryptocyst sunken centrally, raised between opesiules and towards orifice, coarsely granular, pierced by circular pseudopores ventrally and proximally. Opesiules paired, asymmetrical, elliptical to teardrop-shaped, proximolateral to the opesia, 173–260 μm (ẋ = 212 ± 19 µm; CV = 9; N = 47 on 5 specimens) long by 160–246 μm (ẋ = 200 ± 20 µm; CV = 10; N = 47 on 5 specimens) wide (Fig. 2.4). Orifice terminal, circular, 105–207 μm (ẋ = 146 ± 21 µm; CV = 14; N = 50 on 5 specimens) long by 44–135 μm (ẋ = 81 ± 20 µm; CV = 25; N = 50 on 5 specimens) wide, having proximally directed condyles slightly proximal to the midline (Fig. 2.5). Spine bases lacking. Spicules comprising only C-shaped calipers, while compass spicules absent (Fig. 2.6). Ovicells hyperstomial, globular, cleithral, 426–489 μm (ẋ = 457 ± 23 µm; CV = 5; N = 5 on 4 specimens) long by 546–572 μm (ẋ = 561 ± 13 µm; CV = 2; N = 4 on 4 specimens) wide; ectooecia completely calcified, smooth, with median suture and triangular fenestra proximally (Fig. 2.6). Avicularia and kenozooids not observed. Remarks. Amui & Kaselowsky (2006) proposed the name Thalamoporella arabiensis for a cheilostome species from the Bab-el-Mandeb Strait. However, this name was preoccupied by a fossil bryozoan described two years earlier by Guha & Gopikrishna (2004) from the Aquitanian deposits of the Khari Nadi Formation in Kachchh, Gujarat, India, rendering the name of Amui & Kaselowsky (2006) a junior homonym (see Sonar et al. 2022). Consequently, Thalamoporella annmargretae nom. nov. is established here as a replacement name, in accordance with Article 60.3 of the International Commission on Zoological Nomenclature (ICZN 1999). Amui & Kaselowsky (2006) cited SMF 1900 as the holotype of Thalamoporella arabiensis (now Thalamoporella annmargretae nom. nov.), although it was not illustrated in the original publication. The material consists of five unbleached colony fragments, which may have originated from more than one individual colony. Therefore, in accordance with Article 73.2 (ICZN 1999), these fragments must be considered syntypes. We here designate the fragment illustrated in Fig. 2.2 as the lectotype, thereby fixing the application of the name in accordance with Article 74.1 (ICZN 1999). Thalamoporella annmargretae nom. nov. closely resembles Thalamoporella rozieri (Audouin, 1826), a species originally described from the Red Sea, but it lacks the prominent lateral tubercles flanking the orifice. Additionally, the condyles in Thalamoporella annmargretae are more centrally positioned. Another comparable species, Thalamoporella inornata Soule, Soule & Chaney, 1992 from Kuda Huraa, Maldives, lacks avicularia and adoral tubercles but has thick, ribbed zooidal margins (see also Soule et al. 1999, figs 61–63). Both Thalamoporella rozieri and Thalamoporella inornata are characterized by the presence of compass spicules, which are absent in the Bab-el-Mandeb species (Fig. 2.6). Furthermore, Thalamoporella annmargretae nom. nov. exhibits an erect growth habit, contrasting with the encrusting forms of its congeners from the Red Sea and the Maldives.