Stylopoma priscilae, Rodrigues & Larré & Vieira, 2024

Rodrigues, Maria J. S., Larré, Igor R. N. M. & Vieira, Leandro M., 2024, Two new species of Stylopoma (Bryozoa, Cheilostomatida) from the Southwestern Atlantic, Zootaxa 5512 (3), pp. 420-434 : 429-431

Stylopoma priscilae sp. nov.

urn:lsid:zoobank.org:act:C46428D4-07DB-421F-A231-892D928B86BF

( Fig. 4A–F ; Tables 1 , 2 , 3 )

Material examined. Holotype: UFPE 213 , single laminar colony with some fragmented pieces (two fragments mounted on stubs), off Itarema , Ceará, Brazil, 02º16’ S, 39º44’ W, 75 m, coll. 1965–1966 by ‘Canopus’, stn. 8.

Diagnosis. Stylopoma with frontal shield bearing 24–51 pseudopores; primary orifice with a teardrop-shaped poster sinus; condyles well-developed, tab-like, slightly striated; 2–3 adventitious avicularia with a long and acute-subtriangular rostrum; vicarious avicularia spatulate; ooecium globular, pseudoporous, with 10–12 adventitious avicularia on its surface.

Type locality. Off Itarema , Ceará, Brazil.

Etymology. The specific epithet honors Dra. Priscila Araci Grohmann, who donated the type material.

Description. Colony encrusting, unilaminar to multilaminar, becoming erect, foliaceous, bilaminar, with zooids in both faces. Autozooids subrectangular, limited by distinct sutures ( Fig. 4A, B ). Frontal shield nodulose with 24–51 small pseudopores, sometimes immersed in secondary calcification forming sets of two to three pseudopores; umbo absent ( Fig. 4B ). Primary orifice with anter transversely D-shaped ( Fig. 4C ), almost as long as wide, with a smooth distal margin and poster with a teardrop-shaped sinus (0.038 –0.049 mm length x 0.024 –0.033 mm width), about 1/4 of orifice length; condyles tab-like (0.014 –0.028 mm length x 0.014 –0.049 mm width), occupying most of the proximal border on each side of the sinus, distal margin smooth and frontally striated. Secondary orifice poorly developed, with nodular calcification around the primary orifice. Adventitious avicularium (0.092 –0.138 mm length x 0.029 – 0.054 mm width) elongated ( Fig. 4A–D ), 2–3 per zooid: a single latero-oral one often present ( Fig. 4C ), inclined to the frontal plane, often distolaterally directed; one or two additional avicularia on the frontal shield ( Fig. 4A ), with variable orientation and position; rostrum acute, subtriangular, a complete crossbar and an elliptical foramen. Vicarious avicularium variable in length (0.249 –0.364 mm length x 0.083 –0.117 mm width) ( Fig. 4A, D ), as long or slightly larger than an autozooid, proximally semicircular, rostrum spatulate in frontal view; palate occupying more than half the length of the rostrum, incomplete medially; foramen elliptical and elongated; complete crossbar. Vicarious kenozooids with adventitious avicularia may be present between autozooids ( Fig. 4B ). Ovicells prominent ( Fig. 4E, F ), obscuring the orifice of the maternal zooid; ooecium globose, with the same morphology as the frontal shield; 10–12 adventitious avicularia of the same morphology as the others on the ooecial surface; opening of the ooecium obscured in frontal view, semicircular, with a joined proximal labellum ( Fig. 4F ).

Remarks. The holotype here described and figured consists of the sole colony of S. priscilae sp. nov. (with fragmented pieces) found among over 5,000 bryozoan specimens collected by the ‘Akaroa’ and ‘Canopus’ from NE Brazil.

The autozooids of S. priscilae sp. nov. have an orifice with anter D-shaped and poster with a teardrop-shaped sinus, a characteristic shared with twelve other species of Stylopoma . However, S. priscilae sp. nov. is distinguished from other species with a teardrop-shaped sinus by having a pair of tab-like condyles occupying most of the proximal border on each side of the sinus.

Among the species described for Brazil, at least three, S. corallinum , S. faceluciae and S. rotundum , have orifices with a teardrop-shaped sinus. In addition to the differences in the shape of the condyles (rectangular in S. corallinum and squared in S. faceluciae and S. rotundum ), these species are distinguished from S. priscilae sp. nov. by the adventitious avicularia (acute-subtriangular in S. priscilae sp. nov., rhombic in S. corallinum ; subtriangular in S. faceluciae and elliptical in S. rotundum ) ( Winston et al. 2014; Rodrigues et al. 2020).

Among the remaining Stylopoma species worldwide, at least nine, S. haywardi Winston & Woollacott, 2009 , S. horarium Tilbrook, 2006 , S. inchoans Tilbrook, 2000 , S. informata , S. lacrima Tilbrook, 2001 , S. magnistilla Tilbrook, 2001 , S. magnovicellata Silén, 1954 , S. smitti and S. spongites , have an orifice with a teardrop-shaped sinus. Stylopoma priscilae sp. nov. is distinguished by having an orifice with tab-like condyles (rectangular in S. haywardi , S. horarium , S. inchoans , S. informata , S. lacrima and S. magnistilla ; subrectangular in S. smitti and S. spongites ) and a large acute-subtriangular adventitious avicularium (short and subtriangular in S. magnovicellata ) ( Di Martino 2023; Tilbrook 2000, 2001, 2006; Winston 2005; Winston & Woollacott 2009; Rodrigues et al. 2020).

Morphologically, S. multiavicularia , described from Brazil (Costa dos Coqueiros, Bahia; Rodrigues et al. 2020) resembles S. priscilae sp. nov. as it is the only other species in Brazil with a subtriangular acute adventitious avicularium. However, it can be distinguished by the teardrop-shaped sinus (U-shaped in S. multiavicularia ).

Distribution. Endemic; known only from the type locality off Itarema, Ceará, Brazil, 75 m depth, on rhodolith.

Figures

FIGURE 4. Stylopoma priscilae sp. nov., UFPE 213, holotype. A. Autozooids, vicarious avicularia and part of one ovicell (on the right). B. Vicarious kenozooids (arrows) between autozooids. C. Close-up of a primary orifice and a latero-oral adventitious avicularium. D.A spatulate vicarious avicularium between autozooids. E, F. Close-up of an ooecium with adventitious avicularia on its surface; with semicircular aperture and a small labellum (arrow). Scale bars: A, E, 500 µm; B, C, 100 µm; D, 150 µm; F, 200 µm.