Diskeria tasmanica, Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De & Artois, Tom, 2011

Schockaert, Ernest R., Curini-Galletti, Marco, Ridder, Wouter De & Artois, Tom, 2011, On the Calviriidae Martens and Curini-Galletti, 1993 (Platyhelminthes, Proseriata), with the description of three new species, Zootaxa 3034, pp. 32-46 : 39

Diskeria tasmanica n.sp.

Figs 5 and 6

Diagnosis. Species of Diskeria with a copulatory organ with an inner ring of ±50 needles of ±130µm and an outer ring of ±70 needles of ±50µm, all of the same length. The stylet of the accessory organ is ±60µm long and two groups of surrounding needles consist of 10–11 thin needles (±60–80µm) and 11–13 stouter needles (±80µm).

Occurrence. Tasmania, Fossil Island, in the intertidal of a beach with medium coarse sand (October, 1993).

Material studied. One animal studied alive, then strongly squashed for the karyological study and mounted, designated holotype (QM G 230112).

Derivation of the name. The species epithet is derived from the locality where the species was found.

Description. The specimen is more than 1cm in length, and very opaque. However, from the sketches of the living animal, it can be seen that the habitus of this species, and most probably the general anatomy as well, are the same as those of D. gigantea ( Fig. 5 A–B). The most striking differences from D. gigantea are the number of testes (around 20) and differences found in the hard parts. There are about 50 needles of around 130µm, forming the central stylet-like tube of the copulatory organ ( Fig. 6 A) and the outer ring consists of around 70 needles, about 50µm long. The number of needles of the inner and of the outer ring is close to that of D. gigantea , but they are considerably shorter (even shorter than in the individual with the shortest needles of D. gigantea ). Contrary to the situation in D. gigantea , all needles in the outer ring are of the same length. In the highly disrupted individual the accessory organ is found at some distance from the copulatory organ. It consists of a group of needles with a stylet in the middle ( Fig. 6 C). The needles are arranged in a series of 11 relatively stout needles of about 80µm and a series of 10 more slender needles, 60–80µm. A glandular reservoir can be seen and its duct leading to the stylet, 60 µm long. Surprisingly, next to the copulatory organ a second set of two series of needles can be found (see Fig. 6 B), one series of 13 stout needles of 80–100 µm and a series of 11 slender needles, 60 µm long. These needles evidently belong to an accessory organ even though no stylet was found. The two series of needles in both groups are indeed almost identical. It is possible that one of the two accessory organs was in fact in the gut (cannibalism is not unusual in flatworms) or might have been left behind after copulation. Since the first accessory organ is still attached to its glandular reservoir, the needles near the copulatory organ are probably from another individual..

Figures

FIGURE 5. Diskeria tasmanica n. sp. A. Drawing of the living animal. B. Details of the post-pharyngeal genital organs in the living animal.

FIGURE 6. Micrographs and drawings of the hard parts of Diskeria tasmanica n. sp. in the mount used for karyology. A. Corpulatory organ. B. The accessory organ, close to the copulatory organ. C. Second accessory organ in the mount. Scale bar for all figures = 50 µ m.