@article {1495, title = {Investigation of the ultrastructure of Dendrocoelum constrictum (Platyhelminthes, Tricladida) spermatogenesis and mature spermatozoa}, volume = {337}, year = {2014}, month = {2014/9//}, pages = {513 - 520}, abstract = {

To add to our understanding of dendrocoelid spermatozoa and to describe additional phylogenetic characters, the ultrastructure of the testis was investigated in the subterranean freshwater planarian Dendrocoelum constrictum. This is the first study investigating spermatogenesis and spermatozoon ultrastructure in a subterranean freshwater planarian species. We found that the basic structure of spermatozoa in D.\ constrictum is similar to that of other Tricladida that have been studied previously. In fact, D.\ constrictum spermatozoa possess an elongated nucleus, one giant mitochondrion, and two subterminal flagella with a 9 + \‘1\’ pattern. The flagella emerge together from one side of the spermatozoon. However, D.\ constrictum has some characteristics that have not yet been described for other freshwater planarians. In fact, the number of cortical microtubules reaches the maximum number in the anterior and middle part of region I, and then decrease until they disappear towards the posterior extremity of the spermatozoon. The extreme tip of the anterior region of the spermatozoon exhibits a specific external ornamentation of the plasma membrane.

}, keywords = {Dendrocoelum constrictum, Free-living flatworm, Mature spermatozoon, Spermatogenesis, Ultrastructure}, isbn = {1631-0691}, url = {http://www.sciencedirect.com/science/article/pii/S1631069114001632}, author = {Harrath, Abdel Halim and Gammoudi, Mehrez and Mansour, Lamjed and Ahmed, Mukhtar and Sirotkin, Alexander V. and Al Omar, Suliman Y. and Ibrahim, Khalid E. and Alwasel, Saleh H.} } @article {1494, title = {A Transcriptomic-Phylogenomic Analysis of the Evolutionary Relationships of Flatworms}, journal = {Current Biology}, volume = {25}, year = {2015}, month = {2015/05/18}, pages = {1347 - 1353}, publisher = {Cell Press}, abstract = {

The interrelationships of the flatworms (phylum Platyhelminthes) are poorly resolved despite decades of morphological and molecular phylogenetic studies []. The earliest-branching clades (Catenulida, Macrostomorpha, and Polycladida) share spiral cleavage and entolecithal eggs with other lophotrochozoans. Lecithoepitheliata have primitive spiral cleavage but derived ectolecithal eggs. Other orders (Rhabdocoela, Proseriata, Tricladida and relatives, and Bothrioplanida) all have derived ectolecithal eggs but have uncertain affinities to one another. The orders of parasitic Neodermata emerge from an uncertain position from within these ectolecithal classes. To tackle these problems, we have sequenced transcriptomes from 18 flatworms and 5 other metazoan groups. The addition of published data produces an alignment of \>107,000 amino acids with less than 28\% missing data from 27 flatworm taxa in 11 orders covering all major clades. Our phylogenetic analyses show that Platyhelminthes consist of the two clades Catenulida and Rhabditophora. Within Rhabditophora, we show the earliest-emerging branch is Macrostomorpha, not Polycladida. We show Lecithoepitheliata are not members of Neoophora but are sister group of Polycladida, implying independent origins of the ectolecithal eggs found in Lecithoepitheliata and Neoophora. We resolve Rhabdocoela as the most basally branching euneoophoran taxon. Tricladida, Bothrioplanida, and Neodermata constitute a group that appears to have lost both spiral cleavage and centrosomes. We identify Bothrioplanida as the long-sought closest free-living sister group of the parasitic Neodermata. Among parasitic orders, we show that Cestoda are closer to Trematoda than to\ Monogenea, rejecting the concept of the Cercomeromorpha. Our results have important implications for understanding the evolution of this major phylum.

}, isbn = {0960-98221879-0445}, url = {http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4446793/}, author = {Egger, Bernhard and Lapraz, Fran{\c c}ois and Tomiczek, Bart{\l}omiej and M{\"u}ller, Steven and Dessimoz, Christophe and Girstmair, Johannes and {\v S}kunca, Nives and Rawlinson, Kate~A and Cameron, Christopher~B and Beli, Elena and Todaro, M~Antonio and Gammoudi, Mehrez and Nore{\~n}a, Carolina and Telford, Maximilian~J} }