Microcosmus pupa, (SAVIGNY, 1816)

Monniot, Claude, 2002, Stolidobranch ascidians from the tropical western Indian Ocean, Zoological Journal of the Linnean Society 135 (1), pp. 65-120 : 107

MICROCOSMUS PUPA ( SAVIGNY, 1816) ( Figs 27E , 33 )

Cynthia pupa Savigny, 1816: 151 , pl. 5, fig. 2, – Suez.

Microcosmus pupa: Michaelsen, 1919: 58 , pl. 1, figs 10–12, – Suez; C. Monniot, 1973: 58 part, fig. 4B, – Suez;? Kott, 1985: 356, – Australia, Queensland.

Material

Suez Canal, coll. F.D. Por. Description

The maximum size of the numerous specimens collected is 3 cm in diameter. The body is almost spherical, with sessile siphons. The wrinkled surface of the tunic is covered with sediment and epibionts. Its consistency is hard. The siphonal spines are thin and sharp, slightly curved ( Fig. 27E ).

The body wall is made opaque by closely-packed and strong muscular fibres, shown well by Savigny. The tentacles are ramified, in two or three orders of size, arising from the base of a velum that is covered with filiform papillae. The space between the tentacles and the prepharyngeal band is raised into thin papillae. The prepharyngeal band makes a deep and wide V ( Fig. 33B ). The round dorsal tubercle bulges. The horns of its C-shaped aperture are interiorly rolled. The dorsal lamina has a smooth edge.

The branchial sac has seven high folds on each side. The formula in a 25 mm specimen is:

Figures

Figure 27. Siphonal spinules: A, Pyura gangelion; B, Pyura scortea; C, Pyura tongae; D, Microcosmus madagascariensis; E, Microcosmus pupa. Scale bars: A,C,D,E = 100 mm, B = 20 mm.

Figure 33. Microcosmus pupa: A, specimen ventrally opened. B, dorsal tubercle area. Scale bars: A = 1 cm, B = 2 mm.