@article {doi:10.1111/jzs.12214, title = {Diversification and biogeographic history of the Western Palearctic freshwater flatworm genus Schmidtea (Tricladida: Dugesiidae), with a redescription of Schmidtea nova}, journal = {Journal of Zoological Systematics and Evolutionary Research}, volume = {56}, number = {3}, year = {2018}, pages = {335-351}, abstract = {Abstract The freshwater flatworm genus Schmidtea is endemic in the Western Palearctic region, where it is represented by only four species, thus contrasting with the high species diversity of the closely related genus Dugesia within Europe. Although containing an important model species in developmental and regeneration research, viz. Schmidtea mediterranea, no evolutionary studies on the genus Schmidtea have been undertaken. For the first time, we present a well-resolved molecular phylogenetic tree of the four species of the genus, inferred on the basis of two molecular markers, and provide also the first detailed morphological account of Schmidtea nova. The phylogenetic tree generated corroborates an earlier speciation hypothesis based on karyological data and points to chromosomal rearrangements as the main drivers of speciation in this genus. The high genetic divergence between the four species, in combination with previous dating studies and their current geographic distribution, suggests that Schmidtea could have originated in Laurasia but lost most of its diversity during the Oligocene. Thus, its present distribution pattern may be the result of the expansion of three of its four relictual species over Europe, probably after the Pleistocene glaciations. Our detailed morphological study of S.~nova revealed that it shows a number of remarkable features: interconnected testis follicles, parovaria, an ejaculatory duct exiting into the primary as well as the secondary seminal vesicle by means of a nipple, and the wall of the distal section of the ejaculatory duct being sclerotic or chitinized.}, keywords = {Biogeography, molecular phylogeny, Schmidtea, speciation, taxonomy}, doi = {10.1111/jzs.12214}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/jzs.12214}, author = {Leria, Laia and Sluys, Ronald and Riutort, Marta} } @article {1730, title = {Sulphated glycosaminoglycans support an assortment of planarian rhabdite structures}, journal = {Biol Open}, year = {2017}, month = {2017 Mar 16}, abstract = {

Planaria are soft-bodied, bilateral flatworms of the phylum Playhelminthes. They are covered in cilia and use ciliary-gliding to traverse the substratum while hunting. Their body surface is covered in a layer of viscous slime primarily derived from specialised secretory granules known as rhabdites. The slime must somehow stay associated with the surface of the animal in aqueous environments whilst also lubricating the interface of the animal and the surfaces over which the animal moves. The slime prevents damage to the animal\&$\#$39;s soft body and also contributes to adhesion to the substratum. In order to gain insight into how it might achieve these diverse functions, we performed electron microscopic examination of the slime\&$\#$39;s structure. Analysis of two freshwater flatworms from the UK Schmidtea polychroa (Schmidt, 1861) and Polycelis tenuis (Ijima, 1884) revealed a high level of organisation of the slime layer and a variety of ejected slime structures. We show that these structures are rich in sulphated glycosaminoglycans (sGAGs). Most of these (269 of 285 examined) appear to be topologically-closed spheroids that we name ball-GAGs Another class appears to burst to release flower- and star-like clusters which adhere to motile cilia. We also observe fibrous nets that are associated with entrapped bacteria. Examination of the structure of rhabdites ejected onto a porous surface suggests a mechanism by which their structure allows them to both bind to the porous surface and provide a smooth layer over which the animal could glide. Such sGAG-based structures might provide models for the design of artificial biomimetic replacements for tears, saliva, bio-compatible lubricants or drug-delivery vehicles.

}, doi = {10.1242/bio.024554}, author = {Hayes, Matthew J} } @article {FWB:FWB21, title = {The reaction time of leech and triclad species to crushed prey and the significance of this for their coexistence in British lakes}, journal = {Freshwater Biology}, volume = {34}, number = {1}, year = {1995}, pages = {21{\textendash}28}, publisher = {Blackwell Publishing Ltd}, abstract = {1. Three species of leeches, Erpobdella octoculata, Glossiphonia complanata and Helobdella stagnalis, and four species of triclads, Polycelis nigra, P. tennis, Dugesia polychroa and Dendrocoelum lacteum, commonly coexist on stony shores in productive British lakes. All species are food limited and there is much overlap in their diet. For both leech and triclad communities, coexistence of species is through the occurrence of food refuges. Leeches are more successful than triclads at capturing live prey, whereas both groups feed on damaged prey, comprising incapacitated, live or dead animals that are leaking body fluids. If triclads are better than leeches at exploiting damaged prey, this could be a mechanism for their coexistence.2. Laboratory experiments investigated the comparative speeds at which leeches and triclads responded to crushed prey. Young and adult predators were offered a crushed specimen of the oligochaete Tubifex tubifex, the snail Lymnaea peregra, the crustacean Asellus aquaticus or the chironomid Chironomus sp., and their reaction times recorded. These four prey groups constitute the main diet of the predators in the field. Only D. polychroa and D. lacteum showed a significantly different reaction time between young and adults to crushed prey, and the reason for this is unclear. All predators, except H. stagnalis and D. polychroa, showed a difference in reaction time to the four types of prey, presumably a consequence of differences in both the {\textquoteleft}quality{\textquoteright} and {\textquoteleft}concentration{\textquoteright} of the different prey fluids, and there were some differences between predators in their speed of reaction to the same prey type. The following sequence, from fastest to slowest, in general reaction time to prey was obtained: E. octoculata, D. polychroa, P. tenuis, D. lacteum, P. nigra, H. stagnalis and G. complanata.3. The location of the damaged food by the predators can be explained partly in terms of their foraging behaviour, with E. octoculata, D, polychroa and P. tenuis exhibiting a more seek-out strategy than other species which have a more sit-and-wait behaviour, and partly on the level of sophistication of their chemosensory system used to detect leaked prey fluids. This system is highly developed in triclad species but poorly developed in leeches.4. In a second type of experiment in which prey, L. peregra, A. aquaticus or Chironomus sp., were offered at different time intervals after crushing to H, stagnalis and P. tenuis, few predators fed on food crushed for 24 h or longer, although a few leeches fed on Chironomus crushed for up to 72 h.5. It is concluded that coexistence of leech and triclad species on stony shores in lakes is assisted by partitioning of food on a damaged or live basis.}, issn = {1365-2427}, doi = {10.1111/j.1365-2427.1995.tb00419.x}, url = {http://dx.doi.org/10.1111/j.1365-2427.1995.tb00419.x}, author = {SEABY, R.M.H. and MARTIN, A.J. and YOUNG, J.O.} } @article {1668, title = {The Distribution, Abundance, Feeding Habits, and Population Biology of the Immigrant Triclad Dugesia polychroa (Platyhelminthes: turbellaria) in Toronto Harbour, Canada}, volume = {43}, year = {1974}, month = {1974}, pages = { - 699681}, publisher = {[Wiley, British Ecological Society]}, abstract = {(1) The feeding habits, distribution, abundance and population biology of the immigrant triclad Dugesia polychroa have been studied over a period of 20 months. (2) Using serological techniques, it was found that the food sources of D. polychroa were the tubificid oligochaetes (84.4\%) the gastropods (12.0\%) and the isopods and amphipods (3.6\%). (3) The distribution of D. polychroa in Toronto Harbour was limited, not by food but by gross pollution, to the highly enriched areas around the islands of the harbour complex. (4) The abundance of D. polychroa was estimated at 2220/m2. (5) The weight and length D. polychroa followed a typical allometric growth curve. (6) The triclad population exhibited a yearly maximum and minimum size. The maxima, in August, were characterized by a maximum mean individual length, maximum biomass percentage and a maximum proportion of adults. This was followed by a rapid decline to minima which were characterized by a minimum mean length, and biomass percentage. The minima were followed by a period of growth that was initially slow, halted over the winter period and then became very rapid from spring through to the maxima. The length of the breeding period was 10 weeks. (7) In Toronto D. Polychroa exhibited different feeding habits, related to both the differing relative abundance of the food source and different inter-specific competitors, from those of D. polychroa in Britain. (8) The population abundance was consistent with the levels of food sources, which were considerably higher than those found in Britain. (9) The fecundity estimates and the characteristic maxima and minima of the Toronto population were similar to those exhibited by D. polychroa in Britain, but differed in the rate of growth and reproduction, the rate of decline from the maxima to the minima of size, the length of the breeding period and the maximum, but not the total, observed young. The magnitude of these differences, which were in the order of X2.5-3, showed a relationship to temperature. (10) The population biology of D. polychroa in the two differing environments was remarkably similar although temperature-dependent, thus supporting the concept of self-regulatory dynamics.}, isbn = {00218790, 13652656}, url = {http://www.jstor.org/stable/3531}, author = {Boddington, M. J. and Mettrick, D. F.} } @article {1542, title = {PlanMine {\textendash} a mineable resource of planarian biology and biodiversity}, journal = {Nucleic Acids Research}, volume = {44}, year = {2016}, month = {2016/01/04}, pages = {D764 - D773}, publisher = {Oxford University Press}, abstract = {

Planarian flatworms are in the midst of a renaissance as a model system for regeneration and stem cells. Besides two well-studied model species, hundreds of species exist worldwide that present a fascinating diversity of regenerative abilities, tissue turnover rates, reproductive strategies and other life history traits. PlanMine (http://planmine.mpi-cbg.de/) aims to accomplish two primary missions: First, to provide an easily accessible platform for sharing, comparing and value-added mining of planarian sequence data. Second, to catalyze the comparative analysis of the phenotypic diversity amongst planarian species. Currently, PlanMine houses transcriptomes independently assembled by our lab and community contributors. Detailed assembly/annotation statistics, a custom-developed BLAST viewer and easy export options enable comparisons at the contig and assembly level. Consistent annotation of all transcriptomes by an automated pipeline, the integration of published gene expression information and inter-relational query tools provide opportunities for mining planarian gene sequences and functions. For inter-species comparisons, we include transcriptomes of, so far, six planarian species, along with images, expert-curated information on their biology and pre-calculated cross-species sequence homologies. PlanMine is based on the popular InterMine system in order to make the rich biology of planarians accessible to the general life sciences research community.

}, isbn = {0305-10481362-4962}, url = {http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4702831/}, author = {Brandl, Holger and Moon, HongKee and Vila-Farr{\'e}, Miquel and Liu, Shang-Yun and Henry, Ian and Rink, Jochen C} } @article {799, title = {The karyotypes of two Dugesia species from Corfu, Greece (Platyhelminthes, Turbellaria)}, journal = {Bijdragen tot de Dierkunde}, volume = {48}, number = {2}, year = {1979}, pages = {187-190}, author = {Ian R. Ball} } @article {754, title = {Planarian (Dugesia polychroa) predation on freshwater gastropod eggs depends on prey species, clutch morphology, and egg size}, journal = {Fundamental and Applied Limnology}, volume = {178}, number = {4}, year = {2011}, month = {03/2011}, pages = {325-339}, abstract = {

Though triclad planarias could limit littoral snail recruitment by preying on eggs with their muscular ventral pharynx, planarian predation on eggs has never been quantified. Intact egg clutches encompassing eight snail species x three developmental stages were offered to Dugesia (= Schmidtea) polychroa (Paludicola: Dugesiidae) individuals (body length = 6-12 mm) in one-on-one, no-choice 24-h feeding trials to gain a first insight on snail egg palatability to dugesiid planarias. Predatory losses were quantified as differences in planaria-present trials vs. parallel planaria-absent controls. D. polychroa predation on snail eggs was generally low. Eggs in monolayered, flat clutches of bithyniids (Bithynia leachii) and planorbids (Planorbis planorbis, Helisoma trivolvis, and Planorbarius corneus) were more susceptible to planarian predation than multilayered eggs in sausage-shaped clutches of physids (Physa acuta) and lymnaeids (Lymnaea stagnalis, Radix auricularia, and Stagnicola fuscus). Planarian predation also was higher on smaller eggs, and was not related to planarian body size. Vulnerability was also markedly species-specific, with appreciable losses recorded only for pre-hatching eggs of P. planorbis and, to a lesser extent, H. trivolvis. The results suggest that, with the possible exception for the soft-clutch, small eggs of P. planorbis, predation by D. polychroa on eggs does not impact gastropod recruitment appreciably.

}, issn = {1863-9135}, doi = {10.1127/1863-9135/2011/0178-0325}, author = {Lombardo, Paola and Miccoli, Francesco Paolo and Giustini, Marco and Cicolani, Bruno} } @article {167, title = {Freshwater planarians (Platyhelminthes, Tricladida) from the Iberian Peninsula and Greece: diversity and notes on ecology}, journal = {Zootaxa}, volume = {2779}, year = {2011}, month = {02/2011}, pages = {1-38}, author = {Miquel Vila-Farr{\'e} and Ronald Sluys and {\'I}o Almagro and Mette Handberg-Thorsager and Rafael Romero} } @article {307, title = {Freshwater planarians (Platyhelminthes, Tricladida) from the Palearctic section of the African continent: new records, with the description of a new species}, journal = {Zootaxa}, volume = {3182}, year = {2012}, pages = {1-15}, author = {Harrath, A. H. and Ronald Sluys and Merzoug, D. and Yacoubi-Khebiza, M. and Saleh Alwasel and Marta Riutort} } @article {308, title = {A new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from the Afromontane forest in South Africa, with an overview of freshwater planarians from the African continent}, journal = {Zootaxa}, volume = {3551}, year = {2012}, pages = {43{\textendash}58}, author = {Giacinta Angela Stocchino and Ronald Sluys and Manconi, Renata} }