Poricella bifurcata Ramalho & Moraes & Salgado & Bastos & Moura 2021, n. sp.

Poricella bifurcata Ramalho & Moraes n. sp.

(Fig. 6D, E)

Material examined. Holotype: MNRJBRY-1430: Brazil, Amapá state (Sta #3, 03°35.4267’N – 049°07.6028’W), 90 m, on rhodoliths, 26 September 2014, collected by Fernando Moraes & Rodrigo Moura (NHo Cruzeiro do Sul).

Etymology. From the Latin (bifurcatus, - a, - um), meaning forked, referring to the distinctive avicularium rostrum with bifurcate tip.

Diagnosis. Colony multilaminar; frontal shield with 3–4 kidney-shaped foramina and a thick, well-developed suboral umbo; orifice with 4 delicate spines (two in ovicellate zooids); large interzooidal avicularia with bifurcated rostrum tip; ovicell globular with roughly textured surface.

Description. Colony encrusting, multiserial, multilaminar. Autozooids longer than wide [L 650–708–772 (SD 47, N 8); W 436–497– 577 µm (SD 53, N 7)], frontal shield roughly textured with 3–4 kidney-shaped foramina near the centre and some circular to oval marginal areolar pores (Fig. 6D). Orifice slightly wider than long [L 164–177–198 (SD 13, N 6); W 171–187– 200 µm (SD 11, N 9)], distal area circular and smooth, proximal border straight or slightly convex; four delicate distal spines, only two visible on ovicellate zooids (Fig. 6E); on the median suboral area, a thickened and well developed umbo present (Fig. 6E), frequently broken at the tip. Interzooidal avicularia large [L 249–331– 395 µm (SD 48, N 10)] placed on an oval cystid delimited by tiny circular pores; rostrum bifurcated; crossbar complete (Fig. 6D, E). Ovicell globular, wider than long [L 231–256–278 (SD 17, N 5); W 338–358– 397 µm (SD 27, N 4)] not closed by the zooidal operculum; ooecial surface similar to the frontal shield (Fig. 6D, E). Intramural budding observed in avicularia (see arrows in Fig. 6D, E).

Remarks. In Cook’s (1977) review of Paleocene to Recent Poricella (as Tremogasterina) none has bifid avicularian rostrum. Two species of Poricella are recorded from Brazil, P. mucronata (Smitt, 1873) and P. frigorosa Winston et al., 2014, both from Rio de Janeiro and Bahia states (Vieira et al. 2008; Winston et al. 2014; Almeida et al. 2017). Poricella mucronata is similar to the new species, in having a strong suboral umbo and 2–4 oral spines, but differs in having up to six frontal foramina, the orifice with straight or little concave proximal border (slightly convex in the new species), and flared, truncate and sometimes raised and upcurved rostrum, lacking the bifurcate tip observed in the new species. Colonies of P. frigorosa, described from Rio de Janeiro and Bahia states (Winston et al. 2014; Almeida et al. 2017) differ in having elongate avicularian rostrum (L 288–464– 576 µm) with straight or slightly concave distal end, fewer but larger foramina (2–3), and a characteristic anchor-shaped suboral mucro.

Despite the limited amount of material analised from Amazon reefs, the holotype is large enough to observe that some characters, such as the shape of the avicularian rostrum, the number of oral spines (4) and the number of foramina (3–4) are constant. Cook (1977) shows the intraspecific variations of some characters but the number of foramina, for example, seems to have some ‘specific’ correlations at least in range, if not in absolute number, while the shape of the distal part of the avicularian rostrum, can be inferred just from one or two well-preserved polymorphs within the colony, owing to its consistency.