Stylopoma corallinum, Rodrigues & Almeida & Vieira, 2020

Rodrigues, Maria J. S., Almeida, Ana C. S. & Vieira, Leandro M., 2020, New species of Stylopoma (Bryozoa, Cheilostomata) from Bahia State northeastern Brazil, Zootaxa 4786 (4), pp. 516-534 : 519-520

Stylopoma corallinum n. sp.

( Fig. 2 A–F; Tables 1, 2)

urn:lsid:zoobank.org:act:7ABE1143-936F-4328-894A-B930BC215AB9

Material examined. Holotype: UFBA 3176.1 , Costa dos Coqueiros, Bahia State, Brazil, 12°44’ S; 38°02’ W, 34 m, coll. 1997 by LAMEB-UFBA . Paratypes: UFPE 116 , UFPE 122 , UFPE 127 , UFPE 133 , UFPE 143 , Costa dos Coqueiros, Bahia State, Brazil, 12°44’– 12°50’ S; 38°04’– 38°11’ W, 23–28 m, coll. 2002–2007 by LAMEB-UFBA. Additional specimens: UFBA 2028.7 , UFBA 2381.11 , UFBA 2386.2 , UFBA 2764.5 , UFBA 2769.1 , Costa dos Coqueiros, Bahia State, Brazil, 12°44’– 12°50’ S; 38°04’– 38°10’ W, 23–50 m, coll. 2002–2007 by LAMEB-UFBA.

Diagnosis. Stylopoma with frontal wall with 38–42 pseudopores; primary orifice with drop-shaped sinus, about 1/3 of the orifice length, and short, rectangular, slightly denticulate condyles; 1–2 latero-oral adventitious avicularia per zooid, slightly above or just below the sinus and distolaterally oriented, almost rhombic in outline; vicarious avicularium spatulate in frontal view; ovicell bearing 2–4 avicularia and with crescentic opening.

Etymology. The species name ‘ corallinum ’ refers to the common association of this Stylopoma species with coral substrata.

Description. Colony encrusting, uni to multilaminar. Autozooids subrectangular to subpolygonal, limited by raised lateral walls ( Fig. 2A ). Frontal wall with rugose surface and small granules of calcification, a raised pointed umbo often present, 38–42 frontal large pseudopores and distinctly elongate marginal pores. Primary orifice transversely D-shaped ( Fig. 2B ), wider than long, with slightly raised rim, distal margin smooth; proximal edge with a drop-shaped sinus about 1/3 of the orifice length; a pair of short proximolateral rectangular condyles [0.004 –0.007 mm high (0.006 ± 0.009; n = 10)] with slightly denticulate and unlipped margins. Secondary orifice slightly elevated, as a complete collar of granular calcification around the primary orifice. Adventitious avicularia small ( Fig. 2 A–E), single or paired, placed proximolateral to the orifice, at the same level, slightly above or just below the sinus and distolaterally oriented; avicularia almost rhombic in frontal view, with rostrum and mandible subtriangular, with complete crossbar and semicircular foramen; an additional frontal avicularium may be present at the zooidal margin, proximal or proximomedial, proximally directed. Vicarious avicularium large ( Fig. 2A, C, D, F ), often as long as autozooids; spatulate in frontal view, proximally semicircular, with a spatulate rostrum, palate incomplete medially, occupying less than half of rostrum length, complete crossbar and inverted V-shaped to elliptical foramen. Ovicells prominent ( Fig. 2D ), obscuring the orifice of the maternal zooid; ooecium globose, with pseudoporous and tubercular surface, bearing 2–4 subtriangular to rhombic avicularia; opening crescentic, with entire proximal labellum and without a distinct suture, not visible in frontal view.

Remarks. Among all congeners, S. corallinum n. sp. most resembles Stylopoma haywardi Winston & Woollacott, 2009 in having latero-oral avicularium distally oriented, frontal wall with a pointed suboral umbo and vicarious avicularium large and spatulate. However, S. haywardi has a frontal wall with more than 80 pseudopores, larger orifices (0.091 –0.127 mm long and 0.109 –0.127 mm wide vs. 0.073 –0.084 mm long and 0.099 –0.117 mm wide in S. corallinum n. sp.), a funnel-shaped sinus in spite of drop-shaped, and the vicarious avicularium lacks a median constriction ( Winston & Woollacott 2009).

Among species previously reported in Brazil, only two other species, S. hastata and S. spongites , also have adventitious avicularia with subtriangular rostrum. Stylopoma corallinum n. sp. differs from both species in having rectangular and slightly denticulate condyles (they are short and smooth in S. hastata and S. spongites ) ( Tilbrook 2001; Ramalho et al. 2018). Another species from Brazil, S. variabilis , has vicarious avicularium similar to that of S. corallinum n. sp. but the avicularium of the new species has broader distal rostrum rather than spatulate and parallel-sided as found in S. variabilis . Other differences among these species include the adventitious avicularium (more elliptical in frontal view in S. variabilis and rhombic in S. corallinum n. sp.), sinus (varying from U-shaped to funnel-shaped in S. variabilis and drop-shaped in S. corallinum n. sp.) and condyles (subrectangular and smooth in S. variabilis and rectangular and slightly denticulate in S. corallinum n. sp.).

Distribution. Brazil: Bahia State. Stylopoma corallinum n. sp. is a shallow water species found in the depth interval of 23–50 m, mainly associated with corals and rhodoliths.

Figures

FIGURE 2. Stylopoma corallinum n. sp. A–D. UFBA 3176.1, holotype. A. Polygonal autozooids and vicarious avicularium. B. Primary orifice and adventitious avicularium. C. Group of autozooids and vicarious avicularia. D. Ovicell, autozooids and vicarious avicularium. E–F. UFPE 116, paratype. E. Autozooids with prominent umbos. F. Group of autozooids and vicarious avicularia. Scale bars: A. 400 µm; B. 50 µm; C. 500 µm; D–F. 400 µm.