Cunina octonaria McCrady

Cunina octonaria McCrady

(Figs 31–32)

References consulted. Mayer 1910: 460–465, 473, pl. 55, figs 1–2. Vannucci 1957: 82–84. Kramp 1959a: 199– 200, fig. 307. Kramp 1961: 282–283. Goy 1979: 286–287, fig. 28. Bouillon 1999: 433–434, fig. 3.150. Nogueira 2012, fig. 15.

Material. Municipality of Pontal do Paraná, Balneário de Praia de Leste (25º46’32”S – 48º12’15”W): 01/12/ 1997 — 3 specimens; (25º42’65”S – 48º27’85”W): 22/12/1997 — 5 specimens; (25º46’32”S – 48º12’15”W): 22/12/ 1997 — 6 specimens; (25º48’10”S – 48º04’90”W): 22/12/1997 — 10 specimens; (25º50’25”S – 47º55’80”W): 22/12/ 1997 — 9 specimens; (25º44’15”S – 48º21’60”W): 23/01/1998 — 6 specimens; (25º46’32”S – 48º12’15”W): 23/01/ 1998 — 1 specimen; (25º48’10”S – 48º04’90”W): 23/01/1998 — 1 specimen; (25º46’32”S – 48º12’15”W): 20/02/ 1998 — 3 specimens; (25º48’10”S – 48º04’90”W): 20/02/1998 — 3 specimens; (25º46’32”S – 48º12’15”W): 27/05/ 1998 — 1 specimen; (25º42’65”S – 48º27’85”W): 28/10/1998 — 1 specimen; (25º46’32”S – 48º12’15”W): 28/10/ 1998 — 3 specimens; (25º48’10”S – 48º04’90”W): 28/10/1998 — 2 specimens; (25º48’10”S – 48º04’90”W): 25/11/ 1998 — 4 specimens; (25º50’25”S – 47º55’80”W): 25/11/1998 — 2 specimens; (25º42’65”S – 48º27’85”W): 21/12/ 1998 — 1 specimen; (25º46’32”S – 48º12’15”W): 22/01/1999 — 2 specimens; (25º46’32”S – 48º12’15”W): 24/03/ 1999 — 5 specimens; (25º48’10”S – 48º04’90”W): 24/03/1999 — 2 specimens.

Reference specimens deposited. MZUSP 1494, 1 specimen, MZUSP 1497, 1 specimen, MZUSP 1503, 7 specimens, MZUSP 1526, 7 specimens, MZUSP 1489, 2 specimens.

World distribution. Tropical regions of the three great oceans and in the Mediterranean Sea (Kramp 1961; Bouillon et al. 2004). Western Atlantic; southern United States (Kramp 1961), Mexico (Segura-Puertas 1992; Loman-Ramos et al. 2007), Brazil, and northern Argentina (Ramírez & Zamponi 1981).

Distribution in Brazil. From the state of Rio de Janeiro to Rio Grande do Sul (Moreira 1973; Navas-Pereira 1980; 1981; Tronolone 2001; Nogueira 2011, 2012; this study).

Description. Umbrella flattened (very flat in most specimens) 0.7–4.12 mm in diameter. Margin formed by lappets (Fig. 31). Walls of the gastric cavity usually opened and without manubrium. Without peripheral canal system. 8 manubrial pouches square, very close together, with the same number of tentacles (Fig. 31). Marginal tentacles solid, with rectangular ectodermal cells, leaving the umbrella to the opposite center of each manubrial pouch. Approximately 70% of the specimens with 8 tentacles and manubrial pouches, and umbrellar diameter smaller than 2.5 mm. 1–5, usually 3 statocysts or only one statocyst (central) per lobe. Otoporpae small, observed only in some better-preserved individuals (Fig. 32).

No larvae were found within the gastric cavity of adults, as is often reported in Cuninidae (Mayer 1910; Kramp 1961; Lucas & Reed 2009). Also there were no parasitic bitentaculate larvae, as reported on other medusae species, and are generally attributed to C. octonaria (Mayer 1910; Vannucci 1957; Bouillon et al. 2006).

Systematic remarks. Thirteen species of the genus are valid (Bouillon & Boero 2000; Schuchert 2013). Five species of Cunina have been found in the southwest Atlantic (Bouillon 1999), four of these in Brazil: Cunina duplicata Maas (Kramp 1959a), Cunina frugifera Kramp (Kramp 1957; Goy 1979), Cunina peregrina Bigelow (Vannucci 1963; Navas-Pereira 1981; Ramírez & Zamponi 1981), and Cunina octonaria (Migotto et al. 2002). Cunina octonaria is distinguished from C. frugifera by the shape of the manubrial pouches and by the absence of peripheral canals (Bouillon 1999). Cunina peregrina is larger (up to 14 mm) has wider marginal lappets, and usually more tentacles (8 to 14, usually 12) (Kramp 1961; Bouillon 1999). Cunina duplicata is even larger (up to 54 mm) and has numerous (up to 29) long and tapered manubrial pouches (Bouillon 1999). Narcomedusae are fragile and sometimes difficult to identify in samples collected with standard plankton nets. Our identification was based on the size, number of tentacles and marginal lappets, absence of peripheral canals, shape and distance between the gastric pouches, and the number and shape of otoporpae of the better-preserved specimens. Other species of the genus may be present among the damaged specimens.