Aetea cultrata, Vieira, Leandro M., Almeida, Ana C. S. & Winston, Judith E., 2016

Vieira, Leandro M., Almeida, Ana C. S. & Winston, Judith E., 2016, Taxonomy of intertidal cheilostome Bryozoa of Maceió, northeastern Brazil. Part 1: Suborders Inovicellina, Malacostegina and Thalamoporellina, Zootaxa 4097 (1), pp. 59-83 : 64

Aetea cultrata n. sp.

( Figs. 6–11 )

Aetea sica: Marcus, 1937: 28 , pl. 4, fig. 9. [ Brazil: São Paulo]

Non Hippothoa sica Couch, 1844: 102 . [British Isles]

Aetea sica: Winston, 1982: 116 , figs. 20, 22. [ USA: Florida]

Aetea sica: Vieira et al., 2008: 12 (in part). [ Brazil: São Paulo and Espírito Santo]

Material examined. Holotype: UFPE 0 76, Riacho Doce, Maceió, Alagoas, Brazil, 9º34'42" S, 35º39'19" W, intertidal, on algae, Sargassum spp., coll. 31 March 2007 by L.M. Vieira. Paratypes: UFPE 0 48, UFPR 0 50, UFPE 0 86, same data as holotype. UFPE 0 62, Pratagy (Reefs of Sereia), Maceió, Alagoas, Brazil, 9º33'55" S, 35º38'40" W, intertidal, on algae, Sargassum spp., coll. 0 7 September 2007 by A.G.A. Borba Jr. Additional material: UFAL 0 212, same data as holotype. UFBA 1605, UFPE 0 74, Pratagy (Sereia), Maceió, Alagoas, Brazil, 9º33'55" S, 35º38'40" W, intertidal, on algae, Sargassum spp., coll. 0 7 September 2007 by A.G.A. Borba Jr. UFPE 107, 110, Jatiúca, Maceió, Alagoas, Brazil, 9º39'10" S, 35º41'40" W, intertidal, on algae, Sargassum spp., coll. 0 9 September 2003 by L.M. Vieira; UFPE 112, Jatiúca, Maceió, Alagoas, Brazil, 9º39'10" S, 35º41'40" W, intertidal, on algae, Sargassum spp., coll. 13 October 2007 by L.M. Vieira.

Diagnosis. Aetea with a punctate creeping basal portion and stalks without constrictions; annulations very rare below the membranous area; stalk and head variable in size, similar in width; little segmented and subtubular zoeciules often arising laterally at the midline of the creeping basal portion.

Description. Colony creeping, delicate, white, forming a uniserial chain of zooids with erect distal tubes. Creeping, often expanded and annulate basal portion, about 0.50–0.70 mm long, slightly punctate and tapering proximally. Erect stalks about 0.389–1.050 mm (0.631 ± 0.175) long and 0.056–0.080 mm (0.068 ± 0.006) wide, with proximal cylindrical minutely punctate portion, rarely forming annulations below the membranous area. Frontal membrane occupying one side of the distal half of stem, bordered by parallel lateral margins, about 0.266– 0.593 mm (0.424 ± 0.086) long, with U-shaped proximal border and straight distal end; basal surface of opesia finely punctate. One or two zoeciules (kenozooids) may be present, tubular to segmented, about 0.10–0.16 mm long, arising from lateral edges of attached creeping region. Embryos not observed.

Etymology. From Latin noun culter, knife, from the knife-shape of the erect portion (stalk and head).

Remarks. Aetea cultrata n. sp. has a longer head portion than A. anguina and A. arcuata . In Alagoas, A. cultrata n. sp. was usually found on Sargassum spp. with other Aetea species, but it is distinct from them by its long parallel-sided head portion. The relatively long head portion is also found in A. curta and A. truncata . The minute spots on the head portion are sometimes inconspicuous owing to calcification. In addition, encrusting portions are ornamented by raised calcification forming annulations.

In Brazil, Vieira et al. (2008) listed A. sica from Fernando de Noronha Archipelago (NE), Espírito Santo and São Paulo. Specimens from Fernando de Noronha, originally assigned to A. recta (see Kirkpatrick, 1890) are cospecific with A. arcuata n. sp. (see above). Marcus (1937) described annulations in some specimens of A. sica from São Paulo, but they may form a minutely punctate portion, as seen in A. cultrata n. sp. from Florida and Alagoas. The zoeciules are also present in specimens from São Paulo ( Marcus 1937), here reassigned to A. cultrata n. sp. Thus, A. sica represents a distinct species and, as with A. truncata , it cannot be considered as present in Brazilian coast.

Distribution. Part of a widespread species complex reported in tropical to subtropical waters, common in tropical Western Atlantic on algae, rocks, shells, and other benthic organisms such as hydroids and bryozoans ( Amathia spp. and Bugula spp.). In Brazil it was previously reported from Espírito Santo and São Paulo as A. sica ( Vieira et al. 2008) . This is the first record of the species in Alagoas. It also occurs on the Atlantic coast of Florida.

Figures

FIGURES 6 – 11. Aetea cultrata n. sp. 6 – 8, UFPE 0 76, holotype, Riacho Doce, Maceió, Alagoas, Brazil; 6, zooids on algae, with Arbocuspis bellula; 7, close-up of autozooid with small zoeciule arising from creeping region; 8, close-up of membranous area; 9, specimen from Jatiúca, Maceió, Alagoas, Brazil; 10 – 11, specimen on algae from Florida, USA; 10, autozooids with small zoeciules; 11, close-up of the proximal part of the stalk, showing the slightly punctate surface.