Cnemidocarpa radicosa ( Herdman, 1882 )

Kott, Patricia, 2006, Observations on non-didemnid ascidians from Australian waters (1), Journal of Natural History 40 (3 - 4), pp. 169-234 : 215-216

Cnemidocarpa radicosa ( Herdman, 1882)

Styela radicosa Herdman 1882, p 163 .

Cnemidocarpa radicosa: Kott 1985, p 136 and synonymy.

Distribution

Previously recorded (see Kott 1985): Western Australia (Cockburn Sound); South Australia (St Vincent Gulf); Tasmania (Bruny I. and western and southern coast); Victoria (Bass Strait, Port Phillip Bay ) ; New South Wales (Port Kembla, Port Jackson ); Queensland (Tallebudgera). New records : South Australia ( Kangaroo I., 10–12 m, SAM E3286 ) , Tasmania (Bass Strait, 60 m, QM G308810 ; Port Davey , 3–18 m, SAM E2882–5 ; Banks Strait) ; New South Wales (Bass Point—near Wollongong).

Description

Individuals are upright, the posterior two-thirds expanded into an almost spherical posterodorsal swelling. The short atrial siphon projects laterally from where the postero-dorsal swelling narrows abruptly to an anterior cone with a terminal branchial aperture. The test is thin, flaccid, and wrinkled, but tough, posteriorly produced into root-like projections that may form a bulbous holdfast entangled with sand and shell. The body wall is muscular and only loosely attached to the test. The prebranchial area is narrow and the dorsal tubercle has a horizontal S-shaped slit. The dorsal lamina is wide and smooth-edged. Up to 19 internal longitudinal vessels are on the folds and five between the folds. Two gonads are on the left, the posterior one in the secondary gut loop is almost spherical. Like the anterior gonad on the left, the four or five on the right are sausage-shaped. Gut and gonads are embedded in the body wall, which is thickened across the posterior part of the body.

Remarks

The external shape of the individuals of this species and their wrinkled, tough test resembles that of Cnemidocarpa pedata ( Herdman, 1881) in which gonads may also be firmly embedded in the test, but which is distinguished by the lack of posterior thickening of the body wall, having instead numerous small upright endocarps in the loop of the gut and between the long, branched gonads. Cnemidocarpa stolonifera is another robust species with a similar body shape, although it has deep furrows and grooves rather than wrinkles in the test. It has similar gonads to C. pedata but its apertures are on siphons marked by four deep parallel grooves and they originate close to one another on the anterior part of the body. The siphons of both C. pedata and the present species are separated by at least onethird of the body length. Kott (1985) found that C. stolonifera was distinguished from C. pedata also by its longer stomach and rectum and more numerous stigmata in each mesh.

Cnemidocarpa radicosa has a range around the southern half of the continent, from Cockburn Sound in the west to the Queensland – New South Wales border.