Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 29-30. (Budapest, 1997)

Table 1 Comparison of larval hooks of Taenia rétracta Linstow, 1803 with some other taeniid cestodes (measurements are given in mm) species number of hooks length of large hook length of small hooks Authors * T. polyacantha 62-78 0.169-0.228 0.093-0.139 **** T. sp.* 30-32 0.154 0.115 Gvozdev, 1962 * T. martis americana 24-26 0.134-0.157 0.125-0.141 Verster, 1969 * T. martis martis 28-30 0.183-0.218 0.151-0.169 Verster, 1969 T. taeniaeformis* 34-36 0.370-O.402 0.210-0.261 Verster, 1969 ** T. krepkogorskii 66-72 0.265-0.315 0.182-0.200 Abuladze, 1964 ** T. endothoracicus 52 0.328-0.380 0.189-0.259 **** ** T. twitchelli 28-36 0.184-0.218 0.143-0.178 Verster, 1969 ** T. sp. 52 0.300-0.306 0.200-0.220 Kamiyaetal. 1987 *** T. crassiceps 28-34 0.178-0.200 0.130-0.155 Verster, 1969 «•* T. rétracta 34 0.308 0.211 Abuladze, 1964 *** T. retracta 34-38 0.266-0.314 0.155-0.212 this study • with strobilocercus and armatetrathyridium larvae with polycephalic larvae ratio of hook's blade and handle > 1 •«•• collected from Mongolian rodents (unpublished) for T. krepkogorskii, T. endothoracicus, T. twitchelli (cf. Abuladze 1964), as well as in bicephalic cysticerci of a probably distinct species of Taenia from Malaysian Rattus rattus and R. argentiventer (cf. Kamiya et al. 1987). Larvae in the first group have no cyst and are situated freely in the thoracic or the peritoneal cavity of the host. The strobilocercus and polycephalic larvae have a cyst transudated from the host tissue, but for polycephalic larvae such as T parva and T krepkogorski the tissue of the cyst can disappear, or the endbladder can fuse, constituting a common basis for larvae (cf. Murai et al. 1989). The present larva differs from all these larvae in morphology, rostellar hook number and morphometry. It is not a morphologically typical strobilocercus or armatetrathyridium. The typical strobilocercus first described for T. taeniaeformis is characterised by a usually evaginated scolex which is connected by a long, solid, segmented strobila to a small bladder. The present larva has a bladder which continues in an attenuated appendage and the anterior part of the body is not clearly segmented. Therefore, we named it caudate strobilocercus. Thus, in terms of body shape, the present larva is clearly distinct from larvae recorded in the thoracic and abdominal cavity of rodents and lagomorphs. It is conceivable that the tissue cyst of the present larvae has disappeared. In this case, T. krepkogorski represents the closest species, but there are differences in hook number (66-72 vs. 34-38) and shape.