Licornia aff. diadema ( Busk, 1852 )

Almeida, Ana C. S., Souza, Facelucia B. C., Menegola, Carla & Vieira, Leandro M., 2017, Diversity of marine bryozoans inhabiting demosponges in northeastern Brazil, Zootaxa 4290 (2), pp. 281-323 : 293-295

Licornia aff. diadema ( Busk, 1852)

( Figs. 30–33 ; Table 3)

? Scrupocellaria diadema: Ramalho et al. 2005: 236 ; Ramalho et al. 2009: 36. Licornia diadema: Almeida et al. 2015b: 3 .

Material examined. UFBA 1172 , UFBA 2368–69 , Camamu Bay, 13°53’S, 38°59’W, 18–20 m, coll. October 2012 (on sponge Mycale angulosa ) ; UFBA 1173 , UFBA 1190 , UFBA 2370–74 , Camamu Bay , 13°53’S, 38°59’W, 18– 20 m, coll. October 2012 (on sponge Bubaris sp.) ; UFBA 1574 , UFBA 2375–79 , Todos os Santos Bay, 13°00’S, 38°32’W, 3–8 m, coll. 2013 (on sponge Callyspongia sp.) ; UFBA 1576 , UFBA 2380–83 , Todos os Santos Bay, 13°00’S, 38°32’W, 3–8 m, coll. 2013 (on sponge Desmapsamma anchorata ) ; UFBA 1613 , UFBA 2384–85 Camamu Bay , 13°53’S, 38°59’W, 18–20 m, coll. October 2012 (on sponge Haliclona (Soestella) melana ) ; UFBA 1614 , UFBA 2386–87 , Camamu Bay , 13°53’S, 38°59’W, 18–20 m, coll. October 2012 (on sponge Tedania ignis ). Additional comparative material . UFBA 223 , Litoral Norte , Camaçari, 12°41’S, 38°05’W, 23 m, coll. February 2008 ; UFBA 288 , Todos os Santos Bay, 13°00’S, 38°32’W, coll. 1997 by Orane Alves (specimens studied by Almeida et al. 2015b).

Description. Colony erect, branched, with internodes comprising 6–16 zooids, living specimens pale brown to yellowish. Internode almost straight, with two series of autozooids, except at the axis of the bifurcation (triserial). Autozooids subrectangular, longer than wide, slightly tapering proximally, with rounded distal edges. Opesia oval, occupying more than three-quarters of the zooidal length, broader distally, surrounded proximally by a narrow and smooth cryptocyst. Scutum often seen in ovicelled zooids, inserted at midline of inner edge of the opesia, paddleshaped, covering small part of the frontal membrane. Four to five oral spines, frequently two inner, two outer and one median. Each zooid with a lateral avicularium placed at distal outer edge, small, rostrum triangular with serrated margins, directed laterally and slightly downward. Frontal avicularia axial zooid or near ovicelled zooids; avicularia of axial zooids placed below opesial margin, with raised base and obscuring proximal opesia, rostrum directed obliquely forward, with hooked tip; other zooids sometimes with a small avicularium at inner side just below opesia, rostrum triangular and with a hooked tip, directed proximo-medially. Vibracular chamber present on basal surface of each zooid, conspicuous in frontal view, also seen in axial zooid, almost triangular, with straight and oblique setal groove, with one proximal rhizoidal foramen. Vibracular setae smooth, as long as or longer than two zooids. Axial zooid with single vibracular chamber. Rhizoids tubular with some retroussé hooks, usually only present at branch bases. Ooecia subglobular, with ectooecium perforated by 5–8 elliptical to circular pores with raised edge.

Remarks. Licornia comprises at least 23 recent species mainly distributed in the Indian and Pacific Oceans (Vieira et al. 2013). Only five Licornia species have been reported in the Western Atlantic: Licornia diadema ( Busk, 1852) , Licornia drachi ( Marcus, 1955) , Licornia jolloisii ( Audouin, 1826) , Licornia micheli ( Marcus, 1955) and Licornia regularis ( Osburn, 1940) . The specimens here figured and described may be conspecific with other specimens previously reported from the Atlantic as L. diadema . Licornia diadema is characterized by having zooids with a variably shaped scutum, from club-shaped to rounded, with proximal and distal lobes of equal size, or slightly bifurcated to highly branched (Vieira et al. 2013). Recent studies, however, suggest that L. diadema comprises a species complex, and that many undescribed species were ascribed to this name ( Tilbrook & Vieira 2012; Vieira et al. 2013, 2014; Sokolover et al. 2016). Thus, since the specimens here figured are distinct from the type specimen figured by Tilbrook & Vieira (2012), we prefer to use Licornia aff. diadema until the complete review of this group is done.

Species of Licornia are commonly found attached to algae, corals and also artificial substrata (e.g., Creary 2002; Tilbrook & Vieira 2012; Vieira et al. 2013). Here we found several colonies of Licornia aff. diadema attached to both rugose ( Fig. 9 ) and smooth-textured sponges.

Distribution. Atlantic: Brazil (Bahia and possibly Rio de Janeiro) ( Almeida et al. 2015b).

Figures

FIGURES 30 – 35. 30 – 33. Licornia aff. diadema, UFBA 1190. 30, Frontal surface of branch; 31, Close-up of autozooids showing spines, lateral avicularia and vibracular chambers; 32, Close-up of ovicelled zooids showing scutum and frontal avicularia; 33, Abfrontal surface of branch. 34 – 35. Poricella frigorosa, UFBA 1585. 34, Overview of encrusting colony; 35, Group of zooids showing orificial spines, anchor-shaped frontal mucrones, frontal pores, avicularia and an ovicell. Scale bars: 30, 34 = 500 µm; 31, 33, 35 = 200 µm; 32 = 100 µm.

FIGURES 8 – 12. Some rugose-textured sponges analyzed in the study. Arrows indicate the bryozoan attached to the sponges. 8, Bubaris sp.; 9, Mycale angulosa; 10, Petrosia (Petrosia) weinbergi; 11, Spongosorites sp.; 12, Tedanias ignis. Scale bars: 1 cm.