Turritopsis nutricula McCrady

(Fig. 6)

References consulted. Mayer 1910: 144–146, figs 76–77. Vannucci 1957: 48. Russell 1953: 115–120, fig. 54. Kramp 1961: 66. Goy 1979: 270–271; Bouillon 1999: 410, fig. 3.10. Bouillon et al. 2004: 53, fig. 32. Miglietta et al. 2007: tab. 2. Tronolone 2007: 39–40, figs 2.9–2.10. Nogueira 2012, fig. 4.

Material. Municipality of Pontal do Paraná, Balneário de Praia de Leste (25º50’ S –47º25’): 27/10/1997 — 3 specimens; (25º47’ S – 48º05’W): 20/08/1998 — 1 specimen; (25º49’ S – 47º56’ W): 20/08/1998 — 2 specimens.

Reference specimens deposited. Dzoo-Cn 248, 2 specimens. MZUSP 1496, 1 specimen. MZUSP 1493, 3 specimens.

World distribution. Western Atlantic: from New England (USA) to the coast of Argentina (Ramírez & Zamponi 1981; Miglietta et al. 2007).

Distribution in Brazil. From the state of Pernambuco to Rio Grande do Sul (Goy 1979; Navas-Pereira 1981; Migotto 2002; Tronolone 2007; Nogueira 2011, 2012).

Description. Umbrella bell-shaped, higher than wide, mesoglea thicker at apex. Mature individuals 0.8–4 mm in height. Manubrium large, cross-shaped in cross-section, yellowish to orange. Four compact vacuolated endodermal masses over the manubrium. Four-lipped mouth with continuous row of sessile cnidocyst clusters along the margin. The four radial canals continue through the masses of vacuolated endodermal cells. Interradial gonads. Medusae dioecious, mature females often with embryos or planulae. 80–120 closely spaced marginal tentacles in a single row (Fig. 6). Tentacles with a terminal swelling and adaxial ocelli.

Systematic remarks. Several species of the genus were synonymized by Kramp (1961) as the cosmopolitan Turritopsis nutricula. More recently, Schuchert (2004) revised the genus based on morphological and reproductive characteristics, and showed that some populations may be distinct species. Miglietta et al. (2007) evaluated the genetic diversity of Turritopsis McCrady populations around the world, and based on the findings of Schuchert (2004), considered ten species potentially valid for the genus. Molecular studies suggested that T. nutricula is the only species of the genus from the eastern coasts of the Americas (Miglietta et al. 2007); however no individuals from the southwestern Atlantic were included in this study.

Biological data. Bavestrello et al. (1992) described the ability of the young jellyfish to “reverse” its life cycle, by transforming to the polyp stage. Piraino et al. (1996) described this reversion to polyps or resting stages in all stages of medusae development, even after sexual maturity. This capability makes this species potentially immortal (Piraino et al. 2004).