Thalamoporella tupinamba, Almeida & Larré & Vieira, 2021

Almeida, Ana C. S., Larré, Igor R. N. M. & Vieira, Leandro M., 2021, Ten new species of marine bryozoans (Gymnolaemata: Cheilostomatida) from Brazil, Zootaxa 5048 (4), pp. 511-537 : 513-515

Thalamoporella tupinamba n. sp.

( Fig. 2A–F )

urn:lsid:zoobank.org:act:BDA43D3E-D0F2-4512-9E06-839E0F064FF8

Thalamoporella sp. : Machado & Souza 1994: p. 259, fig. 10; Almeida et al. 2015a: p. 4; Souza & Almeida 2017: p. 265.

Material examined. Holotype: UFBA 682.1 , 12°44’ S, 38°05’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 23 m, coll. by LAMEB-UFBA, 2002 . Paratypes: UFBA 572 , 12°50’ S, 38°11’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 23 m, coll. by LAMEB-UFBA, 2002 ; UFPE 842 , 4 º49’– 5º10’ S, 36º10’– 36º50’ W, Bacia Potiguar , Rio Grande do Norte, Brazil, coll. by Petrobras, 2009–2010. Additional specimens: UFBA 1860.5 , 12°47’ S, 38°08’ W , UFBA 1868.1 , 12°51’ S, 38°12’ W , UFBA 3187.4 , 12°50’ S, 38°11’ W , UFBA 3869.2 , 12°44’ S, 38°05’ W , Camaçari, Costa dos Coqueiros, Bahia, Brazil, 23 m, coll. by LAMEB-UFBA, 2002 ; UFBA 1862.2 , UFBA 1867.1 , UFBA 1873.1 , 12°47’ S, 38°07’ W , Camaçari, Costa dos Coqueiros, Bahia, Brazil, 28 m, coll. by LAMEB-UFBA, 2002 ; UFBA 2292.6 , UFBA 2994.6 , 12°46’ S, 38°05’ W , Camaçari, Costa dos Coqueiros, Bahia, Brazil, 27 m, coll. by LAMEB-UFBA, 2002 ; UFBA 1874.1 , 12°50’ S, 38°10’ W , Camaçari, Costa dos Coqueiros, Bahia, Brazil, 31 m, coll. by LAMEB-UFBA, 2002 ; UFBA 2863.3 , UFBA 2992.3 , 12°46’ S, 38°07’ W , Camaçari, Costa dos Coqueiros, Bahia, Brazil, 21–25 m, coll. by LAMEB-UFBA, 2002 ; UFBA 2993.1 , 12°45’ S, 38°07’ W , Camaçari, Costa dos Coqueiros, Bahia, Brazil, 22 m, coll. by LAMEB-UFBA, 2003 ; UFBA 3092.2 , 12°43’ S, 38°02’ W , Camaçari, Costa dos Coqueiros, Bahia, Brazil, 24 m, coll. by LAMEB-UFBA, 1998 .

Diagnosis. Thalamoporella with unequal opesiules, autozooidal opesia torqued to the adjacent avicularium, spatulate vicarious avicularia slightly longer than autozooids and with asymmetrical rostrum and small transversely oval opesiules, spicules in the form of small and medium-sized calipers and small and medium-sized compasses, and bivalved brood chambers.

Type locality. Camaçari , Bahia, Brazil .

Etymology. In recognition of the Tupinambá, an indigenous Brazilian tribe that lived along the Brazilian Atlantic coastal regions.

Description. Colony encrusting, uni- to multilaminar ( Fig. 2A ).

Autozooids arranged multiserially, rectangular (0.541–0.655– 0.794 mm long, n = 30, SD = 0.059 mm; 0.244– 0.331– 0.385 mm wide, n = 30, SD = 0.038 mm), with concave proximal rim and convex distal rim ( Fig. 2A ). Lateral walls thick, slightly raised with beaded rims, separated by distinct slits. Cryptocyst occupying almost the entire zooidal length, granular, with small pores and proximal half extension; two rounded unequal opesiules, both descending into the basal wall. Polypide tube with small granules, imperforate, with slightly raised distal border ( Fig. 2B ). Gymnocyst restricted to the distal and latero-oral rim, smooth, sometimes forming small adoral tubercles at either side of orifice, rounded, varying in size from almost indistinguishable to small. Opesia subcircular, orificelike, slightly wider than long (0.158–0.176–0.200 mm long, n = 30, SD = 0.009 mm; 0.160–0.184– 0.205 mm wide, n = 30, SD = 0.010 mm); arcuate distally and well-defined by gymnocyst, with sides almost straight, and with a broad and concave proximal rim formed by a cryptocyst bearing small denticles, with a pair of proximolateral subtriangular condyle-like projections ( Fig. 2B ).

Vicarious avicularium slightly longer than the autozooid (0.591–0.676– 0.726 mm long; n = 30, SD = 0.054 mm; 0.234–0.248– 0.265 mm wide, n = 30, SD = 0.014 mm), distally directed, with an imperforate granular cryptocyst occupying almost the proximal half of avicularium length, with a pair of small and transversely oval opesiules; lateral walls thick with beaded rims; spatulate rostrum, asymmetrical, well-marked by distal smooth gymnocyst, with rounded distal rim; cryptocyst reduced at distal rostral area, with semi-elliptical palatal foramen with almost straight proximal rim occupying distal half of avicularium length; latero-proximal mandibular articulations (pivots) subtriangular, symmetrical; adjacent zooids with the orifice torqued to the avicularium ( Fig. 2C, D ).

Embryos brooded inside globular bivalved brood chambers (0.373–0.407– 0.465 mm long; n = 17, SD = 0.024 mm; 0.448–0.494– 0.533 mm wide, n = 30, SD = 0.023 mm); surface with a distinct median suture, opening with a distal acute shape; aperture of brooding zooids with U-shaped rim ( Fig. 2D ).

Spicules in the form of small and medium-sized calipers and compasses ( Fig. 2B, E ). Calipers often smaller than 0.05 mm, but compasses variable, up to 0.20 mm long. Basal walls with a pair of hooked insertions, irregular, occasionally connected to the distal wall ( Fig. 2F ).

Remarks. Thalamoporella tupinamba n. sp. belongs to the Thalamoporella distorta group sensu Soule et al. (1992) (i.e., Thalamoporella distorta Osburn, 1940 , from the Caribbean, Thalamoporella hawaiiana Soule & Soule, 1970 , from Hawaii, and Thalamoporella semitorquata Soule, Soule & Chaney, 1992 , from the Maldives). These species are characterized by the autozooidal opesia torqued to the adjacent avicularium. Differences among these species are related to avicularian morphology—a moderate rostrum with a median constriction and foramen oblong in T. distorta ; a short rostrum with a weak constriction and elliptical foramen in T. hawaiiana ; a very long rostrum with a weak median constriction and subtriangular foramen in T. semitorquata ; and a moderate rostrum with a weak median constriction and elliptical foramen in T. tupinamba n. sp. Other differences include the spicules in the form of calipers that are common in T. tupinamba n. sp. and T. hawaiiana but are considered absent in both T. distorta and T. semitorquata ( Soule et al. 1992) . Calipers of T. hawaiiana are distinctly wicket-shaped with hooked tips, but more rounded and open in T. tupinamba n. sp. Also, autozooids of T. hawaiiana are slightly larger (0.550 –0.900 mm long; 0.300 – 0.430 mm wide) than T. tupinamba n. sp. (0.541 –0.794 mm long; 0.244 –0.385 mm wide).

To date, three species of Thalamoporella have been recorded from Brazil — Thalamoporella evelinae Marcus, 1939 , Thalamoporella falcifera ( Hincks, 1880) (a misidentified taxon on the Brazilian coast; see Vieira et al. 2016) and Thalamoporella floridana Osburn, 1940 . Differences between T. tupinamba n. sp. and T. evelinae include the small adoral tubercles (larger in T. evelinae than T. tupinamba n. sp.) and the presence of vicarious avicularia (absent in T. evelinae ). Thalamoporella tupinamba n. sp. is distinguished from Brazilian specimens assigned to T. falcifera by Marcus (1937) by the presence of vicarious avicularia and spicules in the form of calipers (absent in Marcus’s material). Thalamoporella floridana (sensu Vieira et al. 2016) has small triangular avicularia and no brood chambers.

Distribution. Western Atlantic: Brazil (Bahia and Rio Grande do Norte). Thalamoporella tupinamba n. sp. mainly encrusts hard substrata such as calcareous algae, rhodoliths and coral fragments; 21‒ 28 m.

Figures

FIGURE 2. Thalamoporella tupinamba n. sp., UFBA 682.1, holotype. A. Overview of an encrusting colony. B. Detail of orifice. C. Autozooids and vicarious avicularium. D. Ovicelled zooids, autozooids and vicarious avicularium. E. Spicules. F. Basal walls. Scale bars: A. 1 mm; B. 100 µm; C, D, F. 200 µm; E. 50 µm.