5. Kapsulotaenia saccifera (von Rátz, 1900) Freze, 1963

(Fig. 3C, G)

Syns. Ichthyotaenia saccifera von Rátz, 1900; Acanthotaenia saccifera (von Rátz, 1900) Johnston, 1909; Proteocephalus saccifera (von Rátz, 1900) Johnston, 1912; Proteocephalus saccifer (von Rátz, 1900) Baer, 1927; Crepidobothrium saccifera (von Rátz, 1900) Meggitt, 1927

Type and only known host. Varanus sp. ( Squamata: Varanidae).

Site of infection. Intestine.

Type locality. Papua-New Guinea (more precise locality not provided) .

Additional localities. Not known.

Type material. Syntypes—3 slides with fragments of several specimens including 4 scoleces from Varanus sp., Papua-New Guinea, collected by Ludwig Biró (MHNG-PLAT-36036–37; C116/41—several fragments of immature & mature proglottids & 1 immature spec. of Acanthotaenia biroi (von Rátz, 1900); C116/42— 2 specimens with the scolex, 2 scoleces mixed with 1 specimen and one scolex of Acanthotaenia biroi (von Rátz, 1900); C116/43—fragments of pregravid proglottids with banana-shaped egg clusters).

Material studied. Syntypes; 2 slides with numerous fragments of specimens identified as K. saccifera from Varanus (?) salvadorii (Peters & Doria, 1878), Bensbach River, Western Province, Papua-New Guinea, coll. by I. L. Owen (NHMUK 1980.8.27.1–3).

Morphological description. von Rátz (1900); present study (Fig. 3C, G; see Table 2 for new measurements).

Remarks. The original description of the species (as Ichthyotaenia saccifera) was incomplete, with very few measurements and without any figure (von Rátz 1900). In addition, the host was not identified to the species level (seven species of monitor lizards are currently reported from Papua-New Guinea—Pianka et al. 2004) and the type locality was not specified.

The type material studied by the present authors is in poor condition, which impeded a full redescription of the species. Nevertheless, it was possible to provide the first illustration of a pregravid proglottid and the scolex of K. saccifera, which forms a prominent apical cone surrounded by four lobes bearing small suckers (Fig. 3C). The apical cone contains circular muscle fibres at its base and gland cells in its anterior-most part (Fig. 3C); an apical organ was not observed and is most likely missing. A study of type specimens also enabled us to confirm that the eggs are grouped in elongate, banana-shaped capsules arranged longitudinally or slightly obliquely within the lumen of the uterus (Fig. 3G). This is the most conspicuous feature of the species. Only K. frezei possesses clusters of eggs of similar shape, but differs markedly by the pre-equatorial position of the genital pore (see above and Fig. 3D).

Tapeworms found by I. L. Owen (NHMUK 1980.8.27.1-3) in the Western Province, Papua-New Guinea were misidentified as K. saccifera and in fact belong to another species of Kapsulotaenia, most likely an undescribed species, because its eggs do not form banana-shaped capsules.

The egg capsule of a specimen (NHMUK 1989.2.22.101–105) illustrated by de Chambrier (2006) and designated as Kapsulotaenia saccifera does not belong to K. saccifera and corresponds to another, unidentified species of Kapsulotaenia .