Reproductive Strategies, Karyology, Parasites, and Taxonomic Status ofDugesiaPopulations from Yemen (Platyhelminthes: Tricladida: Dugesiidae)

Abstract

We present new data on the distribution, reproductive strategies, karyology, and taxonomic status of populations of freshwater planarians from Yemen. Nine populations were sampled and significant differences in their reproductive strategies and karyology are reported. The present study presents the first fully documented record of a naturally sexual, diploid (2n = 18) population of a Dugesia species in the eastern part of the Afrotropical region. Morphological characters combined with karyological data suggest that these Dugesia populations from Yemen represent a new species, which is herein described as Dugesia arabica Harrath and Sluys, sp. nov. This new species is mainly distinguishable from other Dugesia species that are distributed exclusively in the Mediterranean basin and in the eastern part of the Afrotropical region by the presence of the following features: well-developed and cone-shaped penis papilla, housing an ejaculatory duct that runs ventrally and has a subterminal and ventral opening; a considerably expanded and folded section of the bursal canal at the level of the oviducal openings; absence of a layer of longitudinal muscles on the copulatory bursa and the bursal canal. Specimens from two populations from Yemen were infested with a gregarine Protozoon.

Infertility in the hyperplasic ovary of freshwater planarians: the role of programmed cell death

“…Our results support earlier studies showing that fertile cocoons of ex-fissiparous specimens only produced 1-3 hatchlings per cocoon compared with sexual species, which can produce up to 15 young per cocoon (Harrath et al 2013b;Stocchino et al 2012).…”

“…The D. arabica specimens were collected from Yemen as described previously (Harrath et al 2013b). For light microscopy, the anterior parts of adult specimens containing the ovaries were fixed in Bouin's fluid and were subsequently preserved in 70 % alcohol.…”

“…They are easily recognized by the presence of hyperplasic ovaries that can be seen through the dorsal body wall. They produce infertile cocoons or, in very rare cases, cocoons with very low fertility (1-2 hatchlings per cocoon), a phenomenon very rarely reported in planarians (Bromley 1974;Harrath et al 2013b;Stocchino et al 2012). …”

A new and aberrant species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from Madagascar

“…In contrast, in Dugesia bifida the testes are well developed in all specimens examined, without anomalies of the germ cells. Moreover, the hyperplasic ovaries in Dugesia bifida are not visible through the dorsal body wall of living animals, in contrast with other species, such as Dugesia sicula Lepori, 1948, Dugesia maghrebiana Stocchino et al, 2009, Dugesia aethiopica , Dugesia afromontana , and Dugesia arabica Harrath & Sluys, 2013 (Stocchino et al 2012, Stocchino and Manconi 2013, Harrath et al 2013). This may be due to the fact that in Dugesia bifida the hyperplasic ovaries are more weakly developed and more expanded in horizontal direction than in vertical direction.…”

“…Among Dugesia species this basic number is shared by only six other species: Dugesia sicula , Dugesia maghrebiana and Dugesia biblica Benazzi & Banchetti, 1972, from the Mediterranean region; Dugesia arabica from Yemen; Dugesia aethiopica and Dugesia afromontana from the Afrotropical region (cf. Stocchino et al 2004, Stocchino et al 2012, Harrath et al 2013). …”