Cranosina gilbertoi Ramalho & Moraes, 2021

Cranosina gilbertoi Ramalho & Moraes n. sp.

( Fig. 2A–C View FIGURE 2 )

Material examined. Holotype: MNRJBRY-1457: Brazil, Pará state ( Sta #6, 00°45.359’N – 046°38.49’W), 50 m, on rhodolith, 28 September 2014, collected by Fernando Moraes & Rodrigo Moura (NHo Cruzeiro do Sul ). GoogleMaps

Etymology. In honour of Gilberto Menezes Amado-Filho, a dear friend and leading Brazilian marine scientist who dedicated his last years to study the Amazon Reef System.

Diagnosis. Small colonies with large and oval autozooids; 11–14 spines around the opesia; large avicularium placed distally of each autozooid with rostrum ending in an open tip; ovicell endozooidal.

Description. Colony encrusting, multiserial, unilaminar; only small, incomplete, fragments found, showing a spiral growth pattern ( Fig. 2A View FIGURE 2 ). Autozooid large, oval, longer than wide [L 464–518–594 (SD 45, N 18); W 280– 355– 414 µm (SD 34, N 23)], separated by narrow grooves, with a distinct tuberculate cryptocyst varying in width, bearing 11 to 14 spines (visible as spine bases) around the opesia [L 349–399–472 (SD 30, N 23); W 173–217– 297 µm (SD 28, N 25)]; large pore chambers on the lateral and distal walls ( Fig. 2B, C View FIGURE 2 ). Interzooidal avicularia [L 125–146–159 (SD 11, N 14); W 61–80– 90 µm (SD 8, N 14)] located distally of each autozooid, directed laterally or proximo-laterally with rostrum ending in an open tip, somewhat trapezoidal in shape, with strong and incomplete condyles ( Fig. 2B, C View FIGURE 2 ); mandible not observed. Ovicell endozooidal; fertile autozooids show a slight elevation and thickening of the distal rim ( Fig. 2C View FIGURE 2 ).

Remarks. The genus Cranosina comprises 10 known species, half of them fossil. This is the first record of a living Cranosina in the Atlantic Ocean ( Bock 2020, accessed 13 November 2020). The two most similar species are C. coronata ( Hincks, 1881) from the Indo-West Pacific, which lacks spines around the opesia, and has interzooidal avicularia always directed laterally ( Hincks 1881; Tilbrook et al. 2001; Tilbrook 2006); and C. colombiana Osburn, 1950 from the East Pacific, which has fewer spines (8–10) surrounding mainly the proximal half of the opesia, narrower cryptocyst, square avicularium chamber ( 150 µm in all dimensions), and slightly longer and narrower (L 500–550–650, W 250–300– 400 µm) autozooids.Another species described from the Pacific Ocean, C. spiralis Chimonides & Cook, 1994 has similar budding pattern (left or right-handed spiral series in the same colony) and distal avicularia, but lacks spines, has larger zooids (510–820 x 320–500 µm), and longer avicularium rostrum ( 150–310 µm) with thick condyles.