Nematoplana hamata, Curini-Galletti & Oggiano & Casu, 2002

Curini-Galletti, M., Oggiano, G. & Casu, M., 2002, The genus Nematoplana Meixner, 1938 (Platyhelminthes: Unguiphora) in eastern Australia, Journal of Natural History 36 (9), pp. 1023-1046 : 1036-1037

Nematoplana hamata sp. nov.

(gures 5, 8C)

Material examined

HOLOTYPE: Australia, New South Wales, Byron Bay , town beach, lower intertidal in medium sand (July 1993), whole mount (lactophenol): G21826.

Other material. One immature from the type locality studied karyologically (July 1993).

Etymology Named after the characteristically hooked shape (lat: hamatus) of the stylet.

Description

The holotype is about 5 mm long, colourless, entirely ciliated. With two pigmented eye-spots located within the brain capsule.

The short, collar-shaped pharynx is located in the posterior fth of the body.

Male genital organs. Numerous testes arranged in two irregular rows between vitellaria in front of the pharynx. The copulatory organ consists of an ovoid muscular bulb (about 85 Mm high and 40 Mm wide), provided with a thick outer coating of circular and inner longitudinal musculature, connected basally to a single seminal vesicle. No sperm were seen within the vesicle. Distally, the bulb is provided with a copulatory stylet. The stylet is tubular, and about 110 Mm long. The proximal end is slightly swollen, with a markedly oblique opening. The tube has a constant width (about 9– 10 Mm) for all of its length. The distal fourth of the stylet is bent at nearly 45ss. The distal opening is about 9 Mm in diameter, and is provided with a slit about 20 Mm long.

Female genital organs. With two rows of three isolated oocytes each, laterally in front of the pharynx. Vitellaria stretch from behind the brain at the level of the seminal vesicle. Female pore behind the male pore.

Karyotype. With n 58. Plates were unsuitable for a karyometrical analysis.

Discussion

The very long, narrowly cylindrical, distally angled stylet of the new species is unique in the genus. Nematoplan a hamata shares with N. martensi and N. pullolineata the absence of an apophysis. The stylet of N. martensi is, however, straight, distally denticulate, and with a distal spike (see above); that of N. pullolineata is smaller (about 30 Mm), and diOEerently shaped (with a proportionally much smaller distal angled part, and a nearly straight ventral side) (cf. Tajika, 1979).