A new naidid oligochaete species (Annelida, Clitellata, Naididae) from Vietnam with asexual reproduction by fragmentation

A new oligochaete of the family Naididae, subfamily Naidinae, Bratislavia gusevi sp. n., was found in a forest stream in Vietnam. The worm is characterized by small size, asexual reproduction by fragmentation, and dorsal bundles of chaetae beginning from segment II. Each dorsal bundle bears one to two hairs and one to two simple-pointed or bifid, rarely trifid, needle chaetae. An additional distinctive feature of the worm is the presence of one to two enlarged simple-pointed needle chaetae in the bundles of segment IV. These chaetae are somewhat longer and markedly wider than the needles in the rest of the segments. The present paper provides an illustrated description of the discovered individuals and discusses the species’ systematic position, asexual reproduction and regeneration.

Vascularisation de la fleur de Spathiphyllum wallisii

The hermaphrodite flowers of Spathiphyllum wallisii have six tepals and six extrorse stamens. Gynoecia are either tri- or quadri-locular. In trilocular gynoecia, three dorsal bundles and three complex ventral bundles, each corresponding to the union of two simple ventral bundles belonging to adjacent carpels, are found in the ovarian wall. In the central axis of the ovary, three placental bundles rise to the level of ovular attachment. Each of these splits into two ovular traces. There are two ovules in each locule. When the gynoecium is quadrilocular, four placental bundles, four dorsal bundles, and four complex ventral bundles are usually present. In the flowers of Spathiphyllum wallisii, each carpel is vascularized by a dorsal bundle and by two simple ventral bundles. The path of the placental bundles is typical of that of Araceae with axile placentation.