Hemicyclopora admirabilis, Ramalho & Rodríguez-Aporta & Gofas, 2022

Ramalho, Laís V., Rodríguez-Aporta, Raquel & Gofas, Serge, 2022, Preliminary account on the bryozoans of the Alboran platform (Western Mediterranean), with description of two new species, Zootaxa 5094 (1), pp. 53-91 : 74-75

Hemicyclopora admirabilis n. sp.

( Fig. 10 )

urn:lsid:zoobank.org:act:8F73297C-9EBB-4554-AC4C-232377E154A3

Material examined. Holotype: MNCN 25.03/4307 : BV12, 112– 120 m; coll. UMA; one living colony encrusting the bryozoan Adeonellopsis distoma . Paratypes: MNCN 25.03/4308 : BV12, 112– 120 m; coll. UMA; one living colony encrusting A. distoma .

Etymology. From the Latin admirabilis , - e, meaning admirable and referring to the beauty of this species.

Diagnosis. Colony encrusting, unilaminar. Autozooids with one row of areolar pores (additional rows near the orifice), and granular frontal shield; orbicular orifice with eight oral spines in autozooids and six in ovicellate zooids. Ovicell produced by a distal kenozooid, ooecium globular, surface finely granular.

Description. Colony encrusting, unilaminar ( Fig. 10A ). Zooids longer than wide [L 557–647–727 (N 10, SD 66), W 444–471–524 μm (N 10, SD 26)], arranged irregularly ( Fig. 10A, B ). Frontal wall convex, finely granular, imperforate, except for one row of areolar pores with additional rows proximo-lateral to the orifice ( Fig. 10A–C ). Orifice orbicular [L 133–151–163 (N 6, SD 10), W 137–149–164 μm (N 10, SD 8)] with concave proximal border ( Fig. 10D ), rounded triangular condyles and short disto-lateral peristome (never developed proximally) bearing eight articulate, stout spines (six in ovicellate zooids) ( Fig. 10A–D ). Ovicell globular, wider than long [L 205–209– 217 (N 3, SD 6), W 245–272–296 μm (N 3, SD 25)], ooecial surface imperforate and finely granular as the frontal shield ( Fig. 10A–C ). Ancestrula not observed.

Remarks. Seventeen Hemicyclopora species are known worldwide, including four Mediterranean species: H. multispinata ( Busk, 1861) , H. collarina Canu & Lecointre, 1930 , H. discrepans ( Jullien & Calvet, 1903) , and H. dentata López de la Cuadra & García-Gómez, 1991 . The latter two species were recorded in the Alboran Sea: H. dentata , collected in the Strait of Gibraltar at 50–60 m depth, lacks oral spines (López de la Cuadra & García- Gómez 1991), and H. discrepans from the Alboran platform, collected at 170 m ( Harmelin & d’Hondt 1992a), shows eight oral spines in both fertile and infertile zooids, a straight or shallow concave proximal edge of the orifice, and conspicuous triangular condyles; zooids are slightly larger (L 720 x W 500 μm), with a smaller orifice (L 132 x W 127 μm), and larger ovicells (L 220 x W 320 μm) ( Reverter-Gil & Fernández-Pulpeiro 1999). Hemicyclopora collarina , originally described from Miocene sediments of northwestern France and subsequently found living in a cave of the French Mediterranean ( Harmelin 2003), has six oral spines (four in fertile zooids), a triangular suboral projection, lacks condyles and lyrula and, according to López de la Cuadra & García-Gómez (1991), the ovicell is closed by a special operculum. Based on this latter character, Ryland (1963) mentioned that H. collarina may be misplaced in Hemicyclopora .

The most similar to the new species is H. multispinata , which was described from Madeira, North Africa (deep water), the Gulf of Cadiz, and was also recorded from Mediterranean waters off France ( Busk 1861; Cook 1968; Zabala & Maluquer 1988; López de la Cuadra & García-Gómez 1994; Rosso & Di Martino 2016; Ramalho et al. 2020b). As the Alboran specimens, it has eight oral spines in non-ovicellate and six in ovicellate zooids, but differs in having a prominent proximal lip forming a triangular projection below the orifice. Berning (2006) studied the Miocene fauna from Niebla (late Tortonian, Spain) and found a tiny colony, which he left in open nomenclature as Hemicyclopora sp. 1 , due to the absence of ovicells and the poor preservation This tiny colony shows a similar orifice shape, lacks the suboral projections, has eight spines in autozooids, as well as two rows of marginal areolar and additional ones proximo-lateral to the orifice. Unfortunately, we cannot confirm that it is conspecific with the new species due to the absence of ovicells.

Figures

FIGURE 10. Hemicyclopora admirabilis n. sp. (Holotype: MNCN 25.03/4307). A. General view of the colony, growing on another bryozoan (Adeonellopsis distoma), showing fertile zooids with six oral spines and infertile zooids with eight spines. B. Detail of some zooids, one fertile zooid with complete ovicell and another at the initial stage of development (arrow). C. Detail of two fertile zooids with a complete kenozooidal ovicell and another at the initial stage of development (arrow). D. Detail of an orifice showing eight oral spines and a pair of condyles. Scale bars: A, 300 µm; B, C, 350 µm; D, 80 µm.