Discoporella salvadorensis Winston, Vieira & Woollacott, 2014

Almeida, Ana C. S., Souza, Facelucia B. C. & Vieira, Leandro M., 2021, Free-living bryozoans (Cheilostomatida, Cupuladriidae) from northeastern and northern Brazil, Zootaxa 4933 (1), pp. 39-62 : 51-55

Discoporella salvadorensis Winston, Vieira & Woollacott, 2014

( Figs 8 , 9 ; Table 2 )

Discoporella salvadorensis Winston, Vieira & Woollacott, 2014: p. 162 , fig. 14.

Discoporella umbellata var. conica: Marcus & Marcus, 1962: p. 304 , pl. 5, figs 23–25; Braga, 1967: p. 9.

? Discoporella umbellata var. conica Canu & Bassler, 1930: p. 12 .

? Discoporella umbellata: Tommasi, 1967: p. 51 (in part); Tommasi et al., 1972: p. 139 (in part).

Discoporella conica: Migotto et al., 2011: p. 268 .

Discoporella salvadorensis: Souza & Almeida, 2017: p. 265 .

Material examined. UFBA 1496.1, BA (Abrolhos Archipelago), 2 colonies; UFBA 182.3, BA (Ilhéus-Porto Seguro), 6 colonies; UFBA 2577.2, BA (Cairu), 6 colonies; UFBA 2245.2, UFBA 2613.2, BA (Maraú), 10 colonies; UFBA 168.2, UFPE 540, BA (off Baía de Todos os Santos), 10 colonies; UFBA 749.1, UFBA 751.1, UFBA 754.1, BA (Baía de Todos os Santos), 6 colonies; UFBA 162.2, UFBA 164.2, BA ( Salvador), 12 colonies; UFBA 002.1, UFBA 004.1, UFBA 018.1, UFBA 021.1, UFBA 022.1, UFBA 023.1, UFBA 651.2, UFBA 855.1, UFBA 857.1, UFBA 1484.2, UFBA 2479.1, UFBA 2738.2, UFBA 2743.1, UFPE 541, UFPE 542, BA (Camaçari), 83 colonies; MOUFPE 64-Akaroa130, MOUFPE 69.2-Akaroa122, SE (Pirambu), 5 colonies; MOUFPE 42.3-Akaroa139, SE (Aracaju), 1 colony; MOUFPE 34.2-Akaroa152, MOUFPE 40.3-Akaroa154, SE (Itaporanga d’Ajuda), 3 colonies; UFPE 531, RN (Guamaré), 3 colonies; MOUFPE 10.1-MA13, MOUFPE 07.3-MA14, MA (Cedral), 5 colonies; MOUFPE 23.1-MA24, MOUFPE 18.2-MA27, MOUFPE 35.3-MA41, PA (Bragança), 5 colonies; MOUFPE 17.3- MA34, PA (S„o Jo„o de Pirabas), 2 colonies; MOUFPE 36.1-MA38, PA (Algodoal), 2 colonies; MOUFPE 25.1- MA39, PA (Salinópolis), 1 colony; MOUFPE 28.1-MA49, PA ( Ilha do Mosqueiro), 1 colony; MOUFPE 02.3-MA56, MOUFPE 03.3-MA62, MOUFPE 05.3-MA60, MOUFPE 22.3-MA59, MOUFPE 24.3-MA68, AP (Macapá), 7 colonies; MOUFPE 27.1-MA65, AP (Araguari River Mouth), 6 colonies.

Description. Colonies dome-shaped ( Figs 8A ; 9A, B ), 2.1–5.2 mm in diameter (mean 2.5 mm; n = 30; standard deviation 0.7 mm). Central area of colony formed by oval to lozenge-shaped autozooids occluded by secondary calcification, with minute central and lateral frontal openings ( Figs 8A, B ; 9A, C ). Autozooids lozenge-shaped, separated by elevated lateral walls, with a D-shaped to oval opesia ( Figs 8C ; 9D ). Cryptocystal shield granular, occupying roughly three-fifths of opesia length, with 4–6 irregularly shaped opesiules sometimes partly occluded by spinous processes. Gymnocyst narrow, evident as a raised rim around autozooid. Vicarious heterozooid lozengeshaped; opesia oval, occupying more than half of zooidal length; with crenulate margin, cryptocyst granular, wider laterally and proximally; gymnocyst evident as a narrow, raised rim around avicularium ( Figs 8C ; 9A, C ). Vibracular chamber subtriangular to C-shaped, located distal to each autozooid and avicularium; opesia auriform; paired and hooked mediolateral flanges; cryptocyst granular, narrow but widest proximally; wide band of smooth gymnocyst evident laterally ( Figs 8D ; 9D ). Colonies with ceased growth have kenozooids (see arrows in Fig. 9B, F ) between autozooids but with some openings remaining and vibracula still functional at colony margin. Basal surface almost smooth, with slight traces of radial grooves and without obvious granules ( Fig. 8D ).

Remarks. Marcus & Marcus (1962) characterized two colony morphologies among Discoporella specimens from several localities in Brazil: discoidal (flat and thin) and dome-shaped (thick). Discoidal specimens attributed by Marcus & Marcus (1962) to D. umbellata are now accepted as D. gemmulifera , as discussed above. Specimens of the second type, with dome-shaped colonies, were assigned to D. umbellata var. conica (Canu & Bassler, 1930) . Canu & Bassler (1930) briefly mentioned the fossil form Cupularia umbellata var. conica from the middle Miocene (Helvetian) of Touraine, France, but provided no description or figures. Both the type locality and stratigraphic occurrence of D. umbellata var. conica suggest that the nominal species is different from specimens found in the Recent Brazilian fauna.

Winston et al. (2014) described D. salvadorensis from a single specimen from Bahia, characterizing it as having a dome-shaped colony, 4–6 opesiules, and a triangular to C-shaped vibracular opesia, with determinate colony growth marked by calcified kenozooids. These authors concluded that their specimen was very different from material studied by Marcus & Marcus (1962), and compared their new species with D. gemmulifera (= D. umbellata sensu Marcus & Marcus 1962 ). The specimen described by Winston et al. (2014) resembles specimens of D. umbellata var. conica described and figured by Marcus & Marcus (1962) in all morphological characters, including the colony morphology, opesia, number of opesiules, vibracular chamber and kenozooids. Zooidal measurements are also similar: autozooids 0.216 –0.324 mm long by 0.180 –0.234 mm wide in specimens described by Winston et al. (2014); 0.2–0.4 mm long by 0.15–0.25 mm wide in specimens characterized by Marcus & Marcus (1962). The only difference between the specimens is in the degree to which marginal autozooids are closed by secondary calcification. In more than 150 colonies examined from Bahia, we found that kenozooids are not constantly present in all colonies with ceased growth, and that this feature can vary even within the same colony ( Fig. 9E, F ). We thus reassign specimens identified by Marcus & Marcus (1962) as D. umbellata var. conica to D. salvadorensis .

Marcus & Marcus (1962) described different astogenetic stages in D. salvadorensis (as D. umbellata var. conica )—young colonies, which are short and conical, with the margin bearing projecting vibracular chambers, and older colonies that have ceased growth, which are larger and higher, with autozooids closed by secondary calcification and kenozooids occurring at the margin ( Marcus & Marcus 1962: pl. 5, fig. 25). We observed these same morphologies among our specimens, representing either young colonies ( Fig. 8 ) or older colonies ( Fig. 9 ).

Besides D. gemmulifera and D. salvadorensis , two other species have been recorded along the Brazilian coast: D. umbellata and D. depressa ( Conrad, 1841) ( Tommasi 1967; Tommasi et al. 1972; Buge 1975; Winston & Migotto 2005; Migotto et al. 2011; Almeida et al. 2015a; Souza &Almeida 2017). Specimens from S„o Sebasti„o (S„o Paulo) ( Winston & Migotto 2005; Migotto et al. 2011) are here referred to D. gemmulifera . Other specimens from S„o Paulo and Rio de Janeiro studied by Tommasi (1967) and Tommasi et al. (1972) that are deposited in the Bryozoa collection of the MZUSP (L.M. Vieira, unpublished data) need to be reexamined; the presence of two colony forms in some of the samples suggest these specimens may represent both D. gemmulifera and D. salvadorensis .

Discoporella salvadorensis differs from D. gemmulifera in having dome-shaped colonies (bowl-shaped in D. gemmulifera ), 4–6 frontal opesiules (6 or more in D. gemmulifera ) and determinate colony growth (semi-determinate in D. gemmulifera ) ( Winston & Vieira 2013). The main differences between D. umbellata and D. salvadorensis include the colony morphology (flat, up to 22 mm in diameter in D. umbellata ; dome-shaped, up to 5.2 mm in diameter in D. salvadorensis ), autozooidal opesia (with paired denticles on the proximal margin in D. umbellata ; denticles absent in D. salvadorensis ) and number of opesiules (8–14 in D. umbellata ; 4–6 in D. salvadorensis ) ( Cook 1965a; Herrera-Cubilla et al. 2008). Differences between D. depressa and D. conica include the colony morphology (flat, up to 18 mm in diameter in D. depressa ; dome-shaped, up to 5.2 mm in diameter in D. conica ), number of opesiules (3–9 in D. depressa ; 4–6 in D. conica ) and basal surface (tuberculate and with conspicuous grooves in D. depressa ; without obvious granules or conspicuous grooves in D. conica ) ( Cook 1965a). According to Di Martino et al. (2017), a revision of all specimens assigned to D. depressa is needed, since several taxa may be involved. This likely applies as well to the Brazilian records by Buge (1975) and Cook (1965a).

Among congeners, D. salvadorensis most resembles D. cookae Herrera-Cubilla, Dick, Sanner & Jackson, 2008 and D. triangula Herrera-Cubilla, Dick, Sanner & Jackson, 2008 in having dome-shaped colonies ( Herrera-Cubilla et al. 2008). Discoporella salvadorensis differs from D. cookae in having colonies with a maximum diameter of 5 mm (10.8 mm in D. cookae ), determinate growth (semi-determinate in D. cookae ), 4–6 opesiules (7–9 in D. cookae ), kenozooids (absent in D. cookae ), and the basal surface without obvious granules or conspicuous grooves (with high density of granules and distinct radial grooves in D. cookae ) ( Herrera-Cubilla et al. 2008). Discoporella conica and D. triangula differ in the size of the colony (maximum diameter 5.2 mm in D. salvadorensis , 3.9 mm in D. triangula ), number of opesiules (4–6 in D. conica ; 5–9 in D. triangula ) and basal surface (without obvious granules in D. salvadorensis ; with conspicuous granules in D. triangula ) ( Herrera-Cubilla et al. 2008).

Distribution. Western Atlantic: Brazil (Paraná, S„o Paulo, Rio de Janeiro, Bahia, Sergipe, Rio Grande do Norte, Maranh„o, Pará and Amapá) ( Marcus & Marcus 1962; Braga 1967; Winston et al. 2014; present study).

Figures

FIGURE 8. Discoporella salvadorensis Winston, Vieira & Woollacott, 2014. A–D. UFBA 857.1, growing colony. A. Colony frontal view with vicarious heterozooid indicated by arrows. B. Autozooids in the central area of the colony and vicarious heterozooid (top left). C. Detail of vicarious heterozooid. D. Detail of vibracular chambers. E. Marginal autozooids with projecting vibracular chambers. F. Colony basal view. Scale bars: A, B. 500 µm; C. 100 µm; D, E, F. 200 µm.

FIGURE 9. Discoporella salvadorensis Winston, Vieira & Woollacott, 2014. A–D. UFBA 2613.2, colony with ceased growth. A. Colony frontal view. B. Colony lateral view (kenozooids indicated by arrows). C.Autozooids in the central area of the colony and a group of vicarious heterozooid (arrow). D. Group of autozooids and its vibracular chambers. E. Marginal autozooids. F. Marginal kenozooids (arrows). Scale bars: A, B. 1 mm; C. 500 µm; D, E, F. 300 µm.