Aetea curta Jullien, 1888

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 : 63-64

Aetea curta Jullien, 1888

( Figs. 4–5 )

? Anguinaria ligulata Busk, 1852b: 30 , pl. 42, fig. 2. [Patagonia] Aetea curta Jullien, 1888: 26 . [ Chile: Hoste Island]

Aetea curta: Hastings, 1943: 473 , pl. 13, fig. 3, figs. 58 A–B. [ Ascension Island] Aetea ligulata: Marcus, 1937: 30 , pl. 4, fig. 10. [ Brazil: São Paulo] Aetea ligulata: Winston, 2008: 323 , fig. 2. [ Belize]

Aetea ligulata: Vieira et al., 2008: 12 . [ Brazil: São Paulo]

Aetea ligulata: Marques et al., 2013: 270 , fig. 2. [ Brazil: São Paulo] Aetea ligulata: Taylor & Tan, 2015: 5 , figs. 2A–F, [ Malaysia]

Material examined. Holotype: MNHN 0 0 0 7, J. Jullien det., 1883, Ile Hoste, Baie Orange, Tierra del Fuego, Chile. Material examined: UFAL 0 122, UFAL 0 123, Sobral sewer outfall, Maceió, Alagoas, Brazil, 9º40'45" S, 35º45'01" W, intertidal, on bryozoans, coll. 18 January 2007 by L.M. Vieira and M.D. Correia; UFAL 0 246, coll. 18 August 2007 by M.D. Correia. UFPE 0 68, UFPE 0 96, 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 0 77, Riacho Doce, Maceió, Alagoas, Brazil, 9º34’42" S, 35º39'19" W, intertidal, on algae Sargassum spp., coll. 31 March 2007 by L.M. Vieira. Additional comparative material. NHMUK 1854.11.15.63, holotype of Aetea ligulata Busk, 1852 b, Pl. 42, C. British Museum Catalogue Collection, Tierra del Fuego, Patagonia, Argentina, coll. by C. Darwin. NHMUK 1947.4.22.342pt, Aetea curta , Ascension Island, Santa Helena, coll. 16 November 1935, Discovery Expedition, Station I, specimen 228A1 (Figured specimen by Hastings 1943, pl. 13, fig. 1).

Description. Colony with uniserial chains of autozooids, creeping, delicate, white, from which erect tubular portions arise. Creeping basal portion punctate, tapering proximally, sometimes corrugated. Stalks often broken, about 0.677–1.099 mm (0.892 ± 0.160) long and 0.056–0.074 mm (0.064 ± 0.006) wide, with a straight tubular portion occupying about half of stalk length, with minute pseudopores and broad wrinkles; membranous area long, about half of total length of stalk, about 0.333–0.593 mm (0.419 ± 0.069) long; dorsal surface of head with minute pseudopores. Frontal membranous area flat, with a rounded proximal border, distally truncated. No basal kenozooids. Embryos not observed.

Remarks. Hastings (1943) redescribed A. curta based on specimens from Santa Helena, which are similar to type specimens examined by us (MNHN 0007). Aetea curta is characterized by its proximally corrugated stalk portion with minute pseudopores, a pattern that is distinct from the annulations found in A. anguina and A. sica .

Some colonies from Maceió have broken stalks, without the distal membranous area. Broken zooids were also observed in specimens identified as Aetea ligulata Busk, 1852 from São Paulo ( Marcus 1937). The weakly calcified appearance of colonies found in Maceió is similar to that observed in specimens from Ascension Island (Southern Atlantic) (NHMUK 1947.4.22.342pt), as well as to Jullien’s specimens. Hastings (1943) suggested both A. curta and A. ligulata are synonymous, but we did not recognize any specimen in the British Museum Catalogue Collection’s slide of A. ligulata (NHMUK 1854.11.15.63). As noted by Fransen (1986), there is a handwritten remark of A.W. Waters on the underside of the slide stating: “ This was mounted in fluid, which dried up, nothing could be seen. All has been remounted ”, suggesting the type of A. ligulata no longer exists. It is possible to recognize the annulated stalks in Busk’s figures ( Busk 1852b: pl. 42), also characteristic of A. curta .

The major problem concerning the usage of the name A. ligulata , whose type was destroyed, is that another species with annulated stalk has been described by Jullien (1888) from Patagonia, Aetea fuegensis Jullien (see Jullien 1888: pl. 7, fig. 7). Examination of type specimens of A. fuegensis (MNHN 0009) revealed colonies with very long stalks (two to three times longer than A. curta ), and the presence of a constriction below the membranous area. This constriction was also described and figured for A. ligulata (Busk 1852) , but it is absent in A. curta . Thus, we believe there are two Aetea species with annulated stalk for Patagonia, as suggested by Jullien (1888). Since Busk (1852b) described A. ligulata as having “cells very long”, we believe it may be cospecific with A. fuegensis .

Owing to the similarities between material from Brazil and those described as A. curta , as well the absence of specimens on the type slide of A. liguata deposited at NHMUK, we believe Busk’s A. liguata may be conspecific with either A. fuegensis (with longer stalk and with constriction below the membranous area) or A. curta (with shorter stalk and without a constriction); thus, we prefer to use the name A. curta for specimens herein reported. In addition, specimens analyzed in this study are conspecific with other specimens reported as A. ligulata from Brazil ( Vieira et al. 2008), Belize (Winston 2008), and Malaysia ( Taylor & Tan 2015).

Aetea truncata ( Landsborough, 1852) , described from Isle of Arran (British Isles), differs from A. curta by the absence of annulations in the stalk region of the zooid. Although Hastings (1943) has noted similarities to specimens reported by Marcus (1938) as A. truncata , São Paulo specimens have a stalk without annulations and shorter zooids. Very short stalks were also observed in specimens from material assigned to A. curta from Australia ( McKinney 1988), which we believe is distinct from both A. curta and A. truncata . Therefore, A. truncata studied by Marcus represents a distinct species, and A. truncata cannot be considered as present in the Brazilian coast.

Distribution. Atlantic Ocean: from Belize to Patagonia and Ascension Island. The species is supposedly widespread by rafting on floating algae. This is the first record of the species in Alagoas.

Figures

FIGURES 2 – 5. Species of Inovicellina from Maceió: 2 – 3, Aetea arcuata, UFPE 0 93, Pratagy, Maceió, Alagoas, Brazil; 2, zooids on algae, with Arbocuspis bellula; 3, close-up of the distal end of the stalk showing the opercular area. 4 – 5, Aetea curta, UFPE 0 77, Pratagy, Maceió, Alagoas, Brazil; 4, close-up of corrugated stalk; 5, close-up of the distal end of stalk showing opercular area.