Pourtalesella duoavicularia Ramalho & Moraes, 2021

Ramalho, Laís V., Moraes, Fernando C., Salgado, Leonardo T., Bastos, Alex C. & Moura, Rodrigo L., 2021, Bryozoa from the reefs off the Amazon River mouth: checklist, thirteen new species, and notes on their ecology and distribution, Zootaxa 4950 (1), pp. 1-45 : 26-27

Pourtalesella duoavicularia Ramalho & Moraes n. sp.

( Fig. 12C–F )

Material examined. Holotype: MNRJBRY-1443 ; Paratype: MNRJBRY-1458: Brazil, Pará state (Sta #6, 00°45.359’N – 046°38.49’W), 50 m, both samples on rhodoliths, 29 September 2014, collected by Fernando Moraes & Rodrigo Moura (NHo Cruzeiro do Sul ) .

Etymology. From the Latin duo (meaning two) plus avicularia, referring to the two types of avicularia characteristic of the species.

Diagnosis. Colony encrusting, starting as a flat sheet and becoming irregular with age. Orifice subcircular with broadly V-shaped sinus. Two kinds of avicularia: small and rounded with serrated rostrum, placed distolaterally to the orifice; larger and triangular with smooth rostrum, placed below and laterally to the orifice. Ovicell globose, flat frontally; ectooecium partially calcified exposing a semicircular area of entooecium with radial ridges; not closed by zooidal operculum.

Description. Colony encrusting, multiserial, initially flat with autozooids regularly disposed, but becoming irregular (huddle) with age, uni- or multilaminar ( Fig. 10A, B ). Autozooids rounded hexagonal, longer than wide [L 329–375–437 (SD 32, N 18); W 239–275– 323 µm (SD 23, N 18)], separated by deep furrows obscured with age ( Fig. 12C, D ). Frontal shield in young zooids smooth, with small, rounded pseudopores becoming smaller with increasing calcification. Primary orifice subcircular [L 80–90–102 (SD 7, N 18); W 82–92– 96 µm (SD 4, N 23)], anter smooth and poster with broadly V-shaped sinus; peristome surrounding the primary orifice proximally and laterally but not covering it ( Fig. 12D ). Two types of avicularia: (1) infrequent, small [L 40–49– 56 µm (SD 8, N 3)] avicularium placed distolaterally to orifice embedded in the peristome, oriented proximolaterally, sometimes slightly larger, on a large cystid and directed upwards; rostrum rounded with serrated edge and crossbar complete, ( Fig. 12E ); (2) more common, larger avicularium [L 73–91– 109 µm (SD 8, N 16)], placed laterally below the orifice, sometimes quite far from it, oriented distolaterally, sometimes raised from the frontal surface; rostrum triangular with smooth edge; crossbar complete ( Fig. 10A–C ). Ovicell globose, wider than long [L 128–146–164 (SD 12, N 11); W 156–176– 205 µm (SD 14, N 10)], usually immersed in calcification, flat frontally; ectooecium partially calcified exposing a semicircular area of entooecium with radial ridges ( Fig. 12E, F ); aperture not closed by zooidal operculum; usually peristome fused laterally with the proximal margin of the ovicell.

Remarks. The main difference between Pourtalesella Winston, 2005 and Buffonellaria Canu & Bassler, 1927 is in the frontal shield, which is perforate in the former genus and imperforate in the latter ( Berning & Kuklinski 2008). Despite these authors mentioned that some autozooids of Buffonellaria may occasionally retain pseudopores in later ontogeny, and this difference may have less systematic significance than previously thought, we prefer to maintain the Amazonas’ specimens in Pourtalesella , owing to the presence of a pseudoporous frontal shield, as seen in other Atlantic Pourtalesella species, pending a revision of this genus.

Four Pourtalesella species have been described from the Atlantic Ocean, two of them from Brazil: P. alipioi (described as Schizopodrella alipioi Marcus, 1955 ), and P. carvalhoi ( Marcus, 1937) . Pourtalesella alipioi has ovicell with pseudoporous entooecium, two latero-oral avicularia with oval rostra, and four distal oral spines. In the original description of Pourtalesella, Winston (2005) mentioned “no spines except on ancestrula”, but the material described by Marcus (1955) has four oral spines and the ooecial surface perforated by several pores. Therefore, the status of S. alipioi requires clarification. On the other hand, P. carvalhoi is similar to P. duoavicularia Ramalho & Moraes n. sp. in the number and shape of avicularia, and shape of the ovicell, but can be distinguished by the sinus shape (very narrow V-shaped in P. carvalhoi , very broad in the new species), and the smaller oral avicularium. Pourtalesella incrassata ( Canu & Bassler, 1928b) , described from North Atlantic, differs from the new species in having narrower V-shaped sinus, single or paired oval avicularia placed laterally to the orifice and oriented distolaterally, and additional avicularia on or close to the ovicellate zooids ( Winston 2005, fig. 253), while P. rugosa ( Osburn, 1940) , also described from North Atlantic, has only oral avicularia with blunt pointed rostra.

Figures

FIGURE 10. Plesiocleidochasma arcuatum Ramalho & Moraes n. sp. (Holotype MNRJBRY-1435).A. General view of a colony on an irregular substrate. B. Zooids showing orifice with spines and umbones (lateral to orifice and suboral). C. Some zooids showing oral distal spines, lateral umbones and one ovicell (asterisk). D. Detail of zooids showing the triangular avicularia. E. Part of the colony showing an ovicellate zooid (asterisk). Scale bars: A, 500 µm; B, 250 µm; C, E, 200 µm; D, 100 µm.

FIGURE 12. A, B. Stephanollona domuspusilla Ramalho & Moraes n. sp. (Holotype MNRJBRY-1543).A. Autozooids having orifice with U-shaped sinus, six oral spines, a suboral avicularium with rounded and serrated rostrum, and a different type of avicularium (lower right) that is elongate, more or less triangular. B. Ovicellate zooid with suboral avicularium. C–F. Pourtalesella duoavicularia Ramalho & Moraes n. sp. (Holotype MNRJBRY-1443). C. General view of the colony. D. Autozooids showing two types of avicularia (see arrows), and orifice surrounded by a raised peristome. E. Ovicell with uncalcified, frontal area and two different kinds of avicularia (arrow). F. Part of a colony showing irregular growth form, two kinds of avicularia (arrow) and ovicells. Scale bars: A, B, D–F, 100 µm; C, 500 µm.