Smittipora harmeriana ( Canu & Bassler, 1929 )

Smittipora harmeriana ( Canu & Bassler, 1929) View in CoL

( Fig. 6.1–4 View FIGURE 6 )

Smittipora abyssicola View in CoL : Harmer 1926: 259, pl. XVI, figs 10–13, non Vincularia abyssicola Smitt, 1873 . Velumella harmeriana Canu & Bassler, 1929: 128 . Smittipora harmeriana View in CoL :? Winston & Heimberg 1986: 11, figs 23, 24; Hayward 1988a: 281, pl. I, fig. (c); Tilbrook 2006: 76, pl.

12, fig. B;? d’Hondt & Mascarell, 2010a: 210; Dick et al. 2020: 211, fig. 5A–C; non Sanjay et al. 2021: 717, pl. 2, figs a,

b; Sanjay et al. 2024a: pl. 2, fig. (d).

Material examined. SMF 40802 (St. 283 KU; Fig. 6.1–4 View FIGURE 6 ).

Description. Colonies encrusting, multiserial, unilamellar ( Fig. 6.1–2 View FIGURE 6 ). Zooids arranged quincuncially, separated by medial groove. Pore chambers and ancestrula not observed.

Autozooids subhexagonal, 429–696 μm (ẋ = 565 ± 67 µm; CV = 12; N = 15 on 1 specimen) long by 325–505 μm (ẋ = 403 ± 45 µm; CV = 11; N = 15 on 1 specimen) wide ( Fig. 6.3–4 View FIGURE 6 ). Gymnocyst not visible. Cryptocyst sunken centrally, raised around the rims, finely granular. Opesia usually subterminal, surrounded by cryptocyst from all sides, but occasionally terminal and cormidial, D-shaped, with weakly developed opesiular indentations at proximolateral corners, occasionally with occlusor lamina distally ( Fig. 6.4 View FIGURE 6 ), 153–205 μm (ẋ = 179 ± 14 µm; CV = 8; N = 15 on 1 specimen) long by 157–194 μm (ẋ = 173 ± 10 µm; CV = 6; N = 15 on 1 specimen) wide. Fertile autozooids with cormidial orifice, lacking an occlusor lamina ( Fig. 6.3 View FIGURE 6 , arrowed) .

Avicularia monomorphic, vicarious, irregularly interspersed among autozooids, lanceolate with acute proximal margins and well-rounded distally, bilaterally symmetrical, 446–577 μm (ẋ = 504 ± 45 µm; CV = 9; N = 15 on 1 specimen) long by 241–354 μm (ẋ = 296 ± 34 µm; CV = 12; N = 15 on 1 specimen) wide ( Fig. 6.3–4 View FIGURE 6 ). Avicularian aperture centrally located, inverted pear-shaped, 160–268 μm (ẋ = 203 ± 28 µm; CV = 14; N = 15 on 1 specimen) long by 63–131 μm (ẋ = 100 ± 20 µm; CV = 20; N = 15 on 1 specimen) wide, without crossbar. Avicularian cryptocyst sunken, surrounding aperture from all sides, granular. Rostrum spatulate, directed distally, indenting proximal cryptocyst of distal autozooid .

Kenozooids not observed.

Remarks. The identification of Smittipora species is challenging due to the limited number of distinguishing characters and their variability within a single colony. Consequently, several similar species have been described, including Smittipora abyssicola ( Smitt, 1873) , Smittipora acutirostris ( Canu & Bassler, 1928a) , Smittipora americana ( Canu & Bassler, 1928b) , Smittipora cordiformis Harmer, 1926 , Smittipora harmeriana ( Canu & Bassler, 1929) , and Smittipora philippinensis ( Canu & Bassler, 1929) . To establish stable species concepts, a re-examination of the type material of all these species is necessary, as species discrimination is not straightforward, and several taxa may eventually prove to be synonyms.

An additional species, Smittipora levinseni ( Canu & Bassler, 1917) , presents a taxonomic issue. Canu & Bassler (1917) introduced “ Velumella ( Onychocella) levinseni ” as a new name for “ Onychocella sp. ” based solely on drawings by Levinsen (1909, pl. XXII, fig. 3a–d), without examining any material or specifying a locality. The absence of directly examined material renders the validity of Smittipora levinseni problematic. Levinsen (1909) also did not indicate a locality or provide any information on the specimen(s) he examined. However, under Article 12 of the International Commission on Zoological Nomenclature ( ICZN 1999), names published before 1931 are considered available if they include a description, definition, or an indication. Thus, Velumella levinseni , which is also the type species of Velumella Canu & Bassler, 1917 , is technically a validly published name. The generic name Velumella has been regarded as a junior synonym of Smittipora ( Bassler 1953) , but Smittipora levinseni continues to be used, with some authors considering it a senior synonym of Smittipora americana (e.g., Winston 1986), while others maintain Smittipora americana (e.g., Di Martino 2022). Given the uncertain status of Levinsen’s material, Smittipora levinseni remains taxonomically dubious, and we refrain from using this name.

Our specimen from the Gulf of Aden is attributed to Smittipora harmeriana as it closely matches the original illustrations by Harmer (1926) and specimens from Mauritius ( Hayward 1988a) and the Gulf of Tonkin ( Dick et al. 2020). Distinctive features of Smittipora harmeriana include bilaterally symmetrical avicularia with a centrally located, elliptical or inverted pear-shaped aperture, and autozooidal opesia with weakly developed proximolateral opesiular indentations ( Fig. 6.4 View FIGURE 6 ). Unlike other similar species, Smittipora harmeriana shows no pronounced sexual dimorphism in opesia size ( Fig. 6.3 View FIGURE 6 ).Additionally, the presence of a prominent occlusor lamina in infertile autozooids ( Fig. 6.4 View FIGURE 6 ), as originally depicted by Harmer (1926), further supports the identification.

The name Velumella harmeriana was proposed by Canu & Bassler (1929) as a new name for Smittipora abyssicola sensu Harmer (1926) from Indonesia, incorrectly termed “ Malasia ” by Canu & Bassler (1929). However, Smittipora abyssicola from the Atlantic Ocean off Florida, USA, as restudied by Di Martino (2022), differs significantly, particularly in the shape of the opesia and the size of the avicularian aperture, as well as the absence of an occlusor lamina.

Reports of Smittipora harmeriana from Komodo, Indonesia ( Winston & Heimberg 1986), show a larger avicularian aperture compared to the Aden specimen, and lack the occlusor lamina, suggesting they may not be conspecific. Similarly, the Smittipora harmeriana from India reported by Sanjay et al. (2021) shows sexual dimorphism in opesia size and asymmetrical avicularia, differing from the original description. However, a specimen from the Lakshadweep Sea ( Sanjay et al. 2024a) may indeed be conspecific.