Archidistoma diminutum subsp.

Archidistoma diminutum (Kott, 1957) sensu lato

Clavelina diminuta Kott, 1957: 89 .

Pycnoclavella diminuta: Kott1990: 73 and synonymy, Australia.

Archidistoma diminuta: Monniot F. & Monniot C. 1996: 203, Micronesia and synonymy. Monniot C. 1997a: 195, Mozambique. Meliane & Ramos-Espla 2001, Arabian peninsula.

Station. TA 51 (MNHN A3 ARC 20)

The colony is made of columnar opaque lobes arising from a common base. Transparent bulbs protrude at their top-side, they contain the thoraces of the zooids. Brown pigment cells can be seen in the tunic and in the zooids preserved in formalin. The zooids, 1cm in length, occupy the whole length of the colony lobes. The oral tentacles, in two orders of size, are located at the base of an undulated velum The number of stigmata is difficult to count, about 35 to 40 in the first row on the right side. The first and the third stigmata rows are curved along the dorsal line. There are 4 rapheal languets. The stomach is in posterior position in the abdomen No gonads are present in this material.

The shape of the colony, the size of the zooids and the number of stigmata lead to identify the material as A. diminutum sensu lato. The highly variable colonies and the wide geographic distribution of the species in the western Indian and western Pacific oceans suggest the presence of more than a single species.