Aglaura aequorea

Nagata, Renato Mitsuo, Júnior, Miodeli Nogueira & Haddad, Maria Angélica, 2014, Faunistic survey of Hydromedusae (Cnidaria, Medusozoa) from the coast of Paraná State, Southern Brazil, Zootaxa 3768 (3), pp. 291-326 : 302

Aequorea forskalea Péron & Lesueur

( Figs 11–12 )

References consulted. Russell 1953: 343–350, fig. 220a. Kramp 1955: p. 265 (as Aequorea aequorea ) Kramp 1957: 38 (as A. aequorea ). Kramp 1959a: 167, figs 234a–b (as A. aequorea ). Kramp 1961: 203–204 (as A. aequorea ). Kramp 1968: 99, fig. 269 (as A. aequorea ). Goy 1979: 281–282, fig. 21 (as A. aequorea ). Goy et al. 1991: 116 (as A. aequorea ). Pagès et al. 1992: 24, fig. 23 (as A. aequorea ). Cornelius 1995: 205–206, fig. 47. Bouillon 1999: 423, fig. 3.78. Bouillon et al. 2004: 118, figs 60e–f.

Material. Municipality of Guaratuba (25°54’S; 48°23’W): 08/08/2003 — 1 specimen; 20/09/2003 — 2 specimens; 18/08/2004 — 19 specimens; 25/11/2004 — 2 specimens.

Reference specimens deposited. MZUSP 901, 2 specimens. MZUSP 906, 1 specimen.

World distribution. Cosmopolitan from tropical and temperate waters ( Russell 1953; Cornelius 1995). Atlantic Ocean: from North Atlantic and the Norwegian Sea, to Patagonia and Atlantic coast of Africa. Mediterranean Sea and Indo-Pacific ( Kramp 1955, 1968; Goy et al. 1990, 1991; Cornelius 1995; Bouillon 1999).

Distribution in Brazil. Northeast coast ( Goy 1979, as A. aequorea ), and from the states of São Paulo to Rio Grande do Sul (Migotto et al. 2002; this study).

Description. Flat umbrella, 14–32 mm in diameter. Short manubrium, mouth large, about half the diameter of umbrella. Numerous radial canals (usually 60–80, sometimes fewer, and up to 160). Tentacles with elongated conical bulbs ( Fig. 12 ), ranging from half, to the same number of radial canals ( Fig. 11 ). 5–10 statocysts between successive radial canals. Gonads along almost the entire length of the radial canals.

Systematic remarks. Currently 24 species of the genus are recognized ( Schuchert 2013). Species identification within the genus Aequorea Peron & Lesueur is difficult, especially because of the fragility of the canals, tentacles, and bulbs ( Pagès et al. 1992), which are of great importance in the taxonomy of the genus. Despite the numerical overlapping of the structures, the shapes of the tentacular bulb and arrangement of excretory papillae are decisive ( Kramp 1965). Five species of the genus have been found in the South Atlantic ( Bouillon 1999), and only A. forskalea in Brazil (Migotto et al. 2002). Although A. forskalea is considered a cosmopolitan species, it is probably a complex of species with wide molecular ( Dawson 2004) and morphological ( Kramp 1965) variation among different populations. Specimens of the British Isles, for instance, have an approximately equal number of tentacles and radial canals, and may reach 17 cm in diameter ( Russell 1953, 1970); whereas specimens of the Benguela Current may reach more than 25 cm, and generally have two tentacles per canal ( Pagès et al. 1992). The specimens studied, as others reported on the Brazilian coast ( Goy 1979; Navas-Pereira 1981) have fewer canals than are reported in the literature ( Russell 1953; Kramp 1961; Cornelius 1995; Bouillon 1999) and nearly two canals per tentacle, which may be because of their smaller size (<3.5 cm). The genus needs a revision with better definitions and delineations of species.

Biological data. Uncommon species in the region, captured mainly from late winter through spring.

Figures

FIGURE 10 – 13. Ectopleura dumortieri (Van Beneden): lateral view (10); Aequorea forskalea Péron & Lesueur: umbrellar margin, disposition of marginal tentacules and radial canals (11) and tentacular bulb (12). Rhacostoma atlanticum L. Agassiz: oral view, rows of gelatinous papillae between radial canals, one radial canal branching (13).