Crepidacantha browni, Almeida & Larré & Vieira, 2021

Almeida, Ana C. S., Larré, Igor R. N. M. & Vieira, Leandro M., 2021, Ten new species of marine bryozoans (Gymnolaemata: Cheilostomatida) from Brazil, Zootaxa 5048 (4), pp. 511-537 : 530

Crepidacantha browni n. sp.

( Fig. 10A–C )

urn:lsid:zoobank.org:act:0445D259-ABA2-4C9A-B65E-A98A511FE2FD

Crepidacantha teres: Almeida et al. 2015a: p. 5 .

Material examined. Holotype: UFBA 728.1 , 12º51’ S, 38º10’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 37 m, coll. by LAMEB-UFBA, 2002 . Paratypes: UFBA 1293.1 , 12º45’ S, 38º06’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 22 m, coll. by LAMEB-UFBA, 2007 ; UFPE 900 , 4 º49’– 5º10’ S, 36º10’– 36º50’ W, Bacia Potiguar, Rio Grande do Norte, Brazil, coll. by Petrobras, 2009–2010 . Additional specimens: UFBA 1294.1 , 12º45’ S, 38º06’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 22 m, coll. by LAMEB-UFBA, 2007 ; UFBA 1295.1 , 12º51’ S, 38º12’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 23 m, coll. by LAMEB-UFBA, 2006 .

Diagnosis. Crepidacantha with rhombic autozooids, 6–10 long marginal spines placed along the distolateral margins, trifoliate primary orifice with convex proximal margin, paired frontal elongate-triangular avicularia directed towards each other and asymmetrically positioned, and ooecium with calcified ectooecium except for a narrow transverse band.

Type locality. Camaçari , Bahia, Brazil .

Etymology. Named in honor of the bryozoologist and geologist David A. Brown (1916–2009).

Description. Colony encrusting, fragile, with light calcification, unilaminar ( Fig. 10A ).

Autozooids rhombic (0.375–0.442– 0.555 mm long, n = 10, SD = 0.053 mm; 0.262–0.323– 0.340 mm wide, n = 10, SD = 0.024 mm), arranged quincuncially, separated by deep grooves; 6–10 long marginal spines placed along the distolateral margins, basal pore-chambers easily seen in marginal zooids. Frontal shield weakly rugose, with small, rounded tubercles, imperforate apart from 2–3 tiny areolar-septular pores around proximal margin ( Fig. 10A ). Primary orifice trifoliate (0.094–0.098– 0.106 mm long, n = 10, SD = 0.004 mm; 0.051–0.059– 0.064 mm wide, n = 10, SD = 0.003 mm), with semicircular distal margin, proximolateral constriction with a pair of triangular condyles, convex proximal margin ( Fig. 10B ), and a thick margin of distal calcification ( Fig. 10A ).

Frontal avicularia small (0.040–0.051– 0.060 mm long, n = 14, SD = 0.005 mm; 0.028–0.036– 0.043 mm wide, n = 14, SD = 0.003 mm), paired, horizontally arranged, proximolateral to orifice, with asymmetric position, directed more or less toward each other, drop-shaped, with proximal semicircular margin, elongate-triangular rostrum, no crossbar and long setiform mandibles ( Fig. 10A–C ).

Ovicelled zooids with primary orifice like that of autozooids. Ovicell hyperstomial, globular (0.135–0.150– 0.174 mm long, n = 10, SD = 0.011 mm; 0.160–0.188– 0.199 mm wide, n = 10, SD = 0.010 mm); ectooecium calcified except for a narrow transverse band distofrontally ( Fig. 10C ).

Remarks. Crepidacantha browni n. sp. belongs to a group of species— Crepidacantha carsioseta Winston & Heimberg, 1986 , Crepidacantha poissonii ( Audouin, 1826) and Crepidacantha teres ( Hincks, 1880) —characterized by having horizontally arranged frontal avicularia ( Brown 1954). Crepidacantha carsioseta , however, has a primary orifice with markedly convex proximal margin forming a distinct proximal lip, suboral umbo, and larger autozooids and orifices (0.396 –0.522 and 0.072 –0.126 mm in length, respectively) ( Winston & Heimberg 1986); in C. browni n. sp. the orifice has a less convex proximal margin, there is no suboral umbo and the autozooids and orifices are smaller (0.231 –0.311 and 0.048 –0.064 mm in length, respectively). These two species are also distinct in the size of avicularia (slightly longer in C. carsioseta than in C. browni n. sp.). Crepidacantha poissonii is distinguished from C. browni n. sp. in having a distinctly trifoliate orifice and well-developed proximal lip ( Brown 1954); in C. browni n. sp., the orifice has margins slightly curved, without a distal sharp process or a distinct proximal lip. Crepidacantha teres is distinguished from C. browni sp. nov. by its orifice with a straight margin ( Brown 1954), unlike the convex proximal margin of the new species.

The other three species of Crepidacantha reported from Brazil, C. longiseta , C. setigera and C. fasciata n. sp., have avicularia arranged vertically ( Brown 1954), being readily differentiated from the avicularia horizontally placed of C. browni n. sp.

Distribution. Western Atlantic: Brazil (Bahia and Rio Grande do Norte). Crepidacantha browni n. sp. usually encrusts corals and rhodoliths; 22– 37 m.

Figures

FIGURE 10. A–C. Crepidacantha browni n. sp., UFBA 728.1, holotype. A. Autozooids. B. Detail of primary orifice. C. Ovicelled zooid. Scale bars: A. 200 µm; B, C. 100 µm.