Thornelya atlanticoensis 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 : 18

Thornelya atlanticoensis Ramalho & Moraes n. sp.

( Fig. 9A–D )

Material examined. Holotype: MNRJBRY-1452: Brazil, Maranhão state (Sta #7, 00°14.742’S – 044°54.089’W), 23 m, on rhodolith, 29 September 2014, collected by Fernando Moraes & Rodrigo Moura (NHo Cruzeiro do Sul ).

Etymology. Referring to the this first record of the genus Thornelya from the Atlantic Ocean.

Diagnosis. Autozooids with tubercular frontal shield, perforate by rounded pseudopores and with slit-like or elliptical areolar pores; 7–8 oral spines. One or two elongate triangular avicularia with serrated rostrum and hooked tip; ovicell globular with several rounded pseudopores and triangular avicularium.

Description. Colony encrusting, multiserial, unilaminar. Autozooids rectangular to polygonal in shape, longer than wide [L 403–472–526 (SD 41, N 16); W 292–375– 469 µm (SD 51, N 20)] ( Fig. 9A–C ). Frontal shield tubercular, perforated by 35–52 rounded pseudopores [9–11– 14 µm diameter (SD 1, N 30)]; some (about 10) slit-like or elliptical marginal areolar pores also present, around the zooids, better visible along lateral margins ( Fig. 9A, C ). Primary orifice [L 102–113–122 (SD 6, N 15); W 82–95– 105 µm (SD 6, N 18)] with semicircular and smooth anter, separated from the shallow and concave poster by small, rounded condyles; 7–8 hollow and long oral spines [18– 21– 27 µm base diameter (SD 2, N 27)] ( Fig. 9B, C ). One or a pair of elongate triangular avicularia [L 128–159– 197 µm (SD 21, N 25)] placed laterally to orifice near the zooidal margin, somewhat raised from frontal surface, directed disto-laterally towards orifice or distally, with complete crossbar, and rostrum with serrated margins and hooked tip ( Fig. 9A, B, D ). Ovicell irregularly globular, wider than long [L 226–241–260 (SD 13, N 5); W 261–271– 280 µm (SD 8, N 5)]; ooecial surface similar to frontal shield, perforated by 26–33 rounded pseudopores, bearing one triangular and smaller avicularium with serrated rostrum oriented proximally; aperture closed by operculum.

Remarks. This is the first record of Thornelya from the Atlantic Ocean. The genus is characterized by a primary orifice with broad and concave proximal border bearing distinct condyles and typically six oral spines ( T. ceylonica has 6–8 oral spines); ovicell densely perforated, often bearing avicularia and closed by the autozooidal operculum ( Tilbrook et al. 2001). Four other Thornelya species are known, from the Indian and Pacific oceans, T. ceylonica ( Thornely, 1905) , T. fuscina Tilbrook et al., 2001 , T.? mila ( Scholz, 1993) and T. perarmata Harmer, 1957 . These species differ from Thornelya atlanticoensis Ramalho & Moraes n. sp. in having small latero-oral avicularia, usually more than two with the rostrum directed towards the orifice (more distally directed in the new species), and fewer oral spines (up to 6), except T. ceylonica , which has 6–8 spines (7–8 in the new species). Thornelya perarmata shares with the new species the presence of a pair of elongate marginal avicularia but differs in having numerous small avicularia placed on the zooidal margins, always six oral spines, and fewer frontal pseudopores ( Ryland & Hayward 1992).

Figures

FIGURE 9. A–D. Thornelya atlanticoensis Ramalho & Moraes n. sp. (Holotype MNRJBRY-1452). A. Colony with both ovicellate and non-ovicellate zooids. B. Autozooids showing orifice with spines, and lateral avicularia. C. Unbleached colony showing zooids with long spines. D. Fertile zooid showing lateral avicularia and ovicell bearing a small avicularium. E–G. Therenia dianae Ramalho & Moraes n. sp. (Holotype MNRJBRY-1431). E. Colony edge with several fertile and infertile zooids and large avicularium. F. Detail of zooids showing orifices with a small sinus, and avicularia. G. Detail of an ovicellate zooid. Scale bars: A, E, 500 µm; B, C, 250 µm; D, 100 µm; F, G, 200 µm.