Carybdea confusa Straehler-Pohl, Matsumoto & Acevedo, 2017

Acevedo, Melissa J., Straehler-Pohl, Ilka, Morandini, André C., Stampar, Sergio N., Bentlage, Bastian, Matsumoto, George I., Yanagihara, Angel, Toshino, Sho, Bordehore, César & Fuentes, Verónica L., 2019, Revision of the genus Carybdea (Cnidaria: Cubozoa: Carybdeidae): clarifying the identity of its type species Carybdea marsupialis, Zootaxa 4543 (4), pp. 515-548 : 525

Carybdea confusa Straehler-Pohl, Matsumoto & Acevedo, 2017

Figs. 1 J–M

Material examined: Holotype ( CASIZ 197981 ), 1 specimen, from Santa Barbara (California) collected 20 meters west of Goleta Pier in 5 meters of water; collected by Shane Anderson, October 21, 1998; preserved in 5% formaldehyde solution . Paratypes, ( CASIZ 197982 ) , 2 specimens, same data as holotype. Five (5) different sized individuals, same data as holotype and paratypes. Two (2) specimens deposited in the Natural History Museum of Barcelona (Museu de Ciències Naturals de Barcelona), Spain ( MZB 2015-1702 ) .

Diagnosis: Gastric phacellae epaulette shaped, single rooted, single stemmed; velarial canals 2 per octant; multiple branched, with rounded tips; pedalial knee bend with thorn-like appendage.

Description: Adult medusa: Bell ( Fig. 1J ) transparent, nearly cuboid, marked interradial furrows, bell densely scattered with white nematocysts of irregular shapes and sizes; bell height up to 20 mm, bell width up to 31.5 mm.

Pedalia ( Fig. 1L ), 4, simple, unbranched flattened, scalpel-shaped, situated in each interradial corner, measures approx. 2/3 bell height in length, outer wing, scattered with round to oval warts of different sizes, white nematocyst bands on outer keel; inner wing, without nematocyst warts; pedalium with one white to flesh coloured tentacle (in preserved specimens). Pedalial canal, lumen diamond shaped with sharp keels, broad at base, flaring slightly from knee bend towards distal end, slightly tapering at distal end, tentacle insertion broader than distal end of canal; going straight to slightly curved through pedalium, volcano to triangular knee bend with small, thorn-like appendage on outer knee bend.

Rhopalia, 4, rhopaliar niche ostium heart-shaped with triangular covering scale, small nematocysts on scales on rare occasions, approx. 1/5 of bell height up from margin; rhopalium with 6 eyes (2 median lens eyes + 2 lateral slit eyes + 2 lateral pit eyes).

Velarium ( Fig. 1M ), in general free of nematocyst warts, only canal roots might show some scattered, small warts, containing 2 broad velarial canal roots per octant, giving rise to 2 to 3 branched velarial canals, canals slim in width, forked at tips, tips rounded, slightly dendritic or lobate, often with more than 2 side branches; canals flanking frenulum simpler, biforked to triforked with few, straight side branches; canals flanking pedalia more complex, root with 2 to 3 main branches with several side branches, resembling antlers.

Manubrium (1/3–1/2 bell height in length), 4 lobes, cruciform manubrium without nematocyst warts, connected to flat and shallow stomach; stomach communicates perradially with 4 gastric pockets leading into velarial canals. 4 gastric phacellae ( Fig. 1K ), epaulette-shaped, mounted on 4 stomach corners, consisting of one circular root per quadrant that gives rise to one stem that splits into branches with several brush-like filaments.

Gonads,4 pairs, broad leaf-like to arrowhead-shaped, separated by unperforated interradial septum, extending from stomach rim to bell margin, tapering towards stomach rim and bell margin, lateral margins overlap; sexes separate but unimorph; ripe gonads milky whitish in both sexes.

Remarks: The specimens from California were first mentioned by Stiasny (1922) and identified as C. rastonii citing Maas (1903, 1910), Bigelow (1909) and Mayer (1910) who declared C. arborifera to be a junior synonym of C. rastonii . This identification was later adopted by Satterlie (1979) and Satterlie & Spencer (1979). In 1990, Larson & Arneson collected cubozoans off Scripps pier, La Jolla (California). Larson, observing what he thought was Carybdea marsupialis in Puerto Rico ( Larson 1976), reclassified the carybdeid species from California (Larson 1990) as C. marsupialis . Later, Larson and Arneson (1990) examined C. rastonii specimens collected at the species type locality (i.e. Gulf of St. Vincent, Australia), as well as C. xaymacana medusae from the Bahamas, which were misidentified as C. marsupialis . The authors concluded that the specimens collected in La Jolla fit more closely the diagnosis of C. marsupialis as described by Bigelow (1938) than that of C. rastonii by Maas (1897). This diagnosis was adopted by Satterlie and Nolen (2001), but not all authors agreed with this reclassification, as the morphological diagnoses did not match ( Fenner 1997; Gershwin 2005a).

Straehler-Pohl et al. (2017) compared all species in question with specimens from California and due to the explicit differences in morphological characters, it was concluded that the Carybdea specimens from California represented members of a new species and was named Carybdea confusa .

Reported distribution of Carybdea confusa : Pacific Ocean (California)

Figures

FIGURE 1. Characters for identification of Carybdea species (species in order of appearance in the text). C. marsupialis: A) adult medusa (preserved) B) epaulette-shaped gastric phacellus C) pedalial canal with rounded knee bend without appendage D) octant of velarium with 3 canal roots, note slender, very sharp tipped velarial canals. C. xaymacana: E) adult medusa (preserved) F) single rooted gastric phacellum, original drawing of Bigelow (1938) G) gastric phacellus H) pedalial canal, note knee bend with appended peak (arrow) I) octant of velarium, note two broad, biforked, sharp-tipped velarial canals. Carybdea confusa: J) adult medusa (preserved) K) single stemmed, single rooted gastric phacellus L) pedalial canal knee bend with appended thorn (arrow) M) octant of velarium, note two multiple branched, round tipped velarial canals. Scale bar: 1 cm.