Pegantha rubiginosa ( Kölliker, 1853 )

Buecher, Emmanuelle, Goy, Jacqueline, J, Mark & Gibbons, 2005, Hydromedusae of the Agulhas Current, African Invertebrates 46, pp. 27-69 : 32-33

Pegantha rubiginosa ( Kölliker, 1853)

Eurystoma rubiginosum: Kölliker 1853: 322 .

Pegantha rubiginosa: Kramp 1961: 276 ; 1968: 127, fig. 343.

Description: Single adult specimen. Hemispherical umbrella, slightly broader than tall, 12.6 mm in diameter. Exumbrella surface smooth. Mesoglea thickened centrally, thinning to lappets. Velum broad. 14 equally-well developed peronia, shallow; 14 marginal lappets, deep, square. 14 tentacles arising from within mesoglea, at periphery of manubrium, long, solid and characteristically banded. Without secondary tentacles on umbrella margin. Mouth simple, circular. Manubrium without gastric pouches. Peripheral canal present, narrow throughout. 4–6 statocysts per marginal lappet; otoporpae present, thin, longer than width of peripheral canal, central ones markedly longer than laterals. Gonads simple, smooth, forming diverticula of margin of oral wall on manubrium.

Material examined: H4987.

Comments: Although Bouillon and Boero (2000 b) have listed some 22 putative species of Pegantha , they only recognise six of these to be valid. These can be separated by a combination of the following characters: overall body-shape, the texture of the exumbrella surface, the number and shape of otoporpae and marginal lappets, as well as by the relative diameter of the peripheral canal throughout its length. Aside from the other species described here (see below), one other species has been recovered from the west Indian Ocean (see references in Kramp 1961): P. triloba Haeckel, 1879 (exumbrella with radiating furrows and ridges; 12–16 slightly pointed marginal lappets, each with up to 20 statocysts; otoporpae of longer than width of peripheral canal).

Distribution: Mediterranean Sea and Atlantic Ocean. This is the first record from the west Indian Ocean. Mainly epipelagic.