A new species of land planarian from Madeira (Platyhelminthes, Turbellaria, Tricladida)

A new species of terrestrial planarian from Madeira, Kontikia bulbosa sp. nov. , is described. The genus Kontikia is redefined and its scope and status reviewed.     

A new species of land planarian from Northern Ireland (Platyhelminthes: Turbellaria)

The anatomy of Kontikia andersoni sp. nov. is described, compared to other species of the genus, and its taxonomic position briefly discussed.     

A revision of the cosmopolitan land planarian Bipalium kewense Moseley, 1878 (Turbellaria: Tricladida: Terricola)

Knowledge of the cosmopolitan land planarian Bipalium kewense is briefly reviewed. A neotype and paraneotypes are designated. External morphology and internal anatomy of the species are redescribed. Karyological studies on B. kewense reveal a diploid chromosome complement of 16; one subtelocentric, three submetacentric and four metacentric chromosome pairs. Taxonomy of B. kewense is revised and full synonomy provided. New synonomies include Placocephalus isabellinus Geba and Bipalium costaricensis Hyman. Species that phenetically resemble B. kewense are divided into three groups primarily on the basis of stripe pattern and cutaneous musculature. A differential diagnosis distinguishing B. kewense from taxa in these groups is provided. Present distribution of the species is mapped. New records are reported from Barbados, Colombia, Costa-Rica, El Salvador, Indonesia, Madagascar, Malaysia, Mauritius, Mexico, Puerto Rico, Tahiti, Taiwan and Zimbabwe. Worldwide B. kewense exhibits a disjunct distribution pattern. In Australia and in the United States a similar pattern of occurrence is evident. The species appears to be dispersed with rooted plants. The natural range of B. kewense extends from Vietnam to Kampuchea, possibly extending to Malaysia. Elsewhere it has been introduced by man. The bipaliid fauna of Vietnam, to which B. kewense belongs, appears to have closer phenetic affinities with the faunas of adjacent southern rather than northern regions.     

Notes on the biology of the freshwater planarian Dugesia bengalensis (Platyhelminthes Turbellaria Tricladida)

Dugesia bengalensis was described by Kawakatsu (Kawakatsu et al., 1983) from specimens collected in West Bengal. We have been studying populations from many different localities in Santiniketan and adjoining areas of West Bengal and can provide additional biological information.The species is hermaphroditic, and its breeding season was found to occur usually between October and March when the winter temperature falls below 25 °C. Outside of the breeding season, D. bengalensis is capable of asexual reproduction by binary fission (Mahapatra et al., 1987).Development of the reproductive organs appeared to be from neoblasts and other mesenchymal cells and, therefore, to be like that typical of other triclads with the exception that some of the neoblasts used for the reproductive tissue appeared to be derived from the intestinal region (Ghosh, 1988; cf. Teshirogi, 1986).During copulation, the partners were oriented in the same direction and not in a head-to-tail position as has been reported (Hyman, 1945) for some planarians.The oval, stalked cocoons were laid in marshy places, and during the period of summer (usually from April to June) they lay dormant in the sandy soil until the onset of the monsoon rains. Then, typically three or four months after they were laid, the cocoons hatched to yield three or four young, a remarkably low number for freshwater triclads (cf Ball & Reynoldson, 1981).     

Global diversity of land planarians (Platyhelminthes, Tricladida, Terricola): a new indicator-taxon in biodiversity and conservation studies

Biodiversity conservation requires prioritization of areas for in situ conservation. In that perspective, the present study documents the global diversity of a component of the soil macrofauna, the land planarians, and concerns an exploratory analysis of their possible role as indicators of biodiversity. Diversity is described by three quantitative methods: (1) hotspots of species richness, selecting areas richest in species, (2) hotspots of range-size rarity, identifying areas richest in narrowly endemic species, and (3) complementarity, prioritizing areas according to their greatest combined species richness. The biodiversity measures of species richness and range-size rarity show a great correspondence in the identification of hotspots of diversity; both measures identify the following seven areas as the most biodiverse for land planarians: Sao Paulo, Florianopolis, western Java, Tasmania, Sri Lanka, North Island/New Zealand, and Sydney. It is discussed to what extent the results for the land planarians correspond with those obtained in other studies that assessed biodiversity hotspots for taxa on a global scale. It is noteworthy that land planarians identify a few global hotspots of diversity that generally do not feature, or only have low rankings, in other studies: New Zealand, southeastern Australia, and Tasmania.     

A new species of freshwater triclad (Platyhelminthes: Tricladida) from Australia

A new species of freshwater triclad, Romankenkius libidinosus sp. nov. , is described from New South Wales, Australia. The species is characterized by a large adenodactyl and unique genito-intestinal connections, and represents the first record of the genus Romankenkius outside Tasmania. The taxonomic and phylogenetic implications of several morphological features of the new species are discussed in the light of a previous phylogenetic study.     

On the taxonomic status of a Dugesia species from Buenos Aires (Platyhelminthes: Turbellaria: Tricladida)

The taxonomic and distributional statuses of the freshwater planarians of South America are imperfectly understood, and a comprehensive review is sorely needed. The species known from the vicinity of Buenos Aires, Argentina, was first described by Böhmig (1902) under the name Planaria dubia Borelli, 1895. Subsequent authors (Kenk, 1930, 1974; Cazzaniga & Curino, 1987) have cast doubt on this assignation. Some have assigned it to Dugesia anceps Kenk; Hyman (1959) was inclined to regard the Buenos Aires planarian as a geographical variant of Dugesia sanchezi Hyman. A comparison of D. sanchezi from the mountainous region of central Chile with specimens from Buenos Aires confirms that the Argentinian material is a distinct species.The differences between the two species are subtle. The Argentinian specimens are distinctive in their possession of infranucleate epithelia of the atria, penis, and bursal canal, as well as in their penial structure. In both species, the epithelia of the atria and bursal canal are glandular. Those of D. sanchezi are nucleate and their secretions are cyanophilous. In the Argentinian specimens, these same epithelia are infranucleate; but while the secretion of the bursal canal is indeed cyanophilous, that of the atrium is erythrophilous. The presence, in these same specimens, of cyanophilous glands opening into the penial vesicles, and of erythrophilous glands whose secretions contribute to a viscous plug in the ejaculatory duct, suggests a difference in the physiology of copulation.It is apparent that the Argentinian specimens are distinct from D. sanchezi Hyman, and probably they represent a new species, one to be described in detail elsewhere. In any case, Hyman's (1959) suggestion that D. sanchezi occurs near Buenos Aires is mistaken; so also is Cazzaniga's & Curino's (1987) identification of specimens from Buenos Aires as D. anceps.     

Selected characters of the copulatory organs in the land planarian family Bipaliidae and their taxonomic significance (Tricladida: Terricola)

Preliminary analysis was made of 76 species in the monotypic family Bipaliidae, for which the copulatory apparatus has been described. Four characters from the copulatory organs were selected: profile of the female organ (three character states), approachment of the ovovitelline ducts to the female organ (two states), shape of the penial papilla (two states), and shape of the male antrum wall (three states). Data were scored for five preliminary ingroup taxa, viz., the restricted genus Placocephalus, and four other a priori defined subgroups within the family, viz., the genus Bipalium sensu stricto and three other informal taxonomic groupings. An artificial outgroup taxon was constructed on the basis of character states generalized from the Geoplanidae subfamilies Caenoplaninae, Pelmatoplaninae and Rhynchodemidae subfamily Microplaninae. Analysis of the data matrix resulted in a single most parsimonious tree with the following topology: (outgroup (Placocephalus (Bipalium, group A (group B1, group B2)))). This revised version was published online in July 2006 with corrections to the Cover Date.     

Assessment of the global potential distribution of the predatory land planarian Artioposthia triangulata (Dendy) (Tricladida: Terricola) from ecoclimatic data

Abstract

Artioposthia triangulata was originally described from New Zealand in 1895 but was subsequently found to have spread to Northern Ireland in 1963 and Scotland and England in 1965. It is now widespread in both Ireland and Scotland, where it has been shown to reduce earthworm numbers to below detectable levels. Ecoclimatic data were used in the computer program CLIMEX to estimate the potential spread of A. triangulata to Europe and the rest of the world. Results indicated it could establish in agricultural land in most of north‐western Europe, and persist in domestic gardens throughout much of central Europe, east and west North America, Australia, southern South America, and South Africa. It is difficult to assess either the extent to which earthworm numbers and diversity would be decreased or how far the effect of their loss to soil structure, nutrient cycling, or wildlife would be detrimental in these areas.     

A new species of giant planarian from Lake Baikal,with some remarks on character states in the Dendrocoelidae (Platyhelminthes,Tricladida, Paludicola)

On the basis of newly collected material the subspecies Bdellocephala angarensis bathyalis Timoshkin & Porfirjeva, 1989 is raised to full species status, B. bathyalis Timoshkin & Porfirjeva, 1989. Specimens of this species have been collected in Lake Baikal from depths ranging between 610 and 1060 m. The species is characterized by a light, uniform brown pigmentation, absence of eyes, distinct atrial folds, and large size. It is suggested that two features may be useful in elucidating the phylogenetic relationships between dendrocoelid genera: pharynx musculature, and presence of an extra layer of circular muscle in the ventral subepidermal body musculature. This revised version was published online in July 2006 with corrections to the Cover Date.     

The effect of starvation on size and survival of the terrestrial planarian Artioposthia triangulata (Dendy) (Tricladida: Terricola)

Ten Artioposthia triangulata were kept without food at 5°C, 10°C, 15°C, 20°C and 23°C. Survival and weights were recorded weekly. All planarians died within one week at 23°C and within three weeks at 20°C. One individual survived for 60 wk at 5°C. A negative exponential equation was fitted to average survival times for planarians kept at 5°C, 10°C, 15°C and 20°C. Negative exponential models could also describe the pattern of degrowth by planarians deprived of food. The results are discussed in relation to possible survival of the planarian outdoors in Northern Ireland and the implications for earthworm populations.     

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

In this paper we report a new species of Dugesia of the family Dugesiidae from Madagascar, representing the fourth species of freshwater planarian known from this global biodiversity hotspot. In some respects the new species is aberrant, when compared with its congeners, being characterized by a head with smoothly rounded auricles, a peculiar course of the oviducts, including the presence of a common posterior extension, and by the asymmetrical openings of the vasa deferentia at about halfway along the seminal vesicle. Further, it is characterized by a ventral course of the ejaculatory duct with a terminal opening, very long spermiducal vesicles and unstalked cocoons. Its diploid chromosome complement with 18 chromosomes represents an uncommon feature among fissiparous species of Dugesia.     

Terrestrial flatworm (Platyhelminthes: Tricladida: Terricola) diversity versus man-induced disturbance in an ombrophilous forest in southern Brazil

Terrestrial flatworms, or Terricola, are sensitive to environmentalchanges and therefore might be excellent indicators of the conservation statusof natural habitats. The present study aimed to answer two main questions: (1)is terrestrial planarian diversity affected by human disturbances, and (2) isthere any species or group of species that indicates such disturbance? The studysite, National Forest of São Francisco de Paula, Brazil, was originallycovered by a mixed ombrophilous forest, but successive reforestations andselective logging have modified the original landscape. We studied Terricoladiversity in the four main habitats in the study area: mixed ombrophilous forest(NA), ombrophilous forest with selective Araucariaangustifolia logging (N), A. angustifoliareforestation (A), and reforestation of Pinus elliottii(P). According to an increasing degree of disturbance, the habitats might beordered as follows: (NA)<(N)<(A)<(P). We conducted 24 surveys in eachhabitat over a period of 1 year. Our results indicate that: (1)Terricola diversity is inversely related to the degree of habitat disturbance;(2) there are species (Geoplana franciscana,Geoplana sp. 5, and possibly Geoplanidae 3 andNotogynaphallia guaiana) that prefer habitats located onthe extreme right along the main axis of a detrended correspondence analysisordination and therefore can be considered as indicators of well preserved,natural habitats. On the other hand there are species(Xerapoa sp. 1, Choeradoplanaiheringi, G. marginata sensu Marcus andGeoplana sp. 2) preferring more disturbed habitats, whichmay form biological indicators of such disturbances.     

Development of the reproductive apparatus of the land planarian Rhynchodemus sylvaticus (Turbellaria: Tricladida) and its significance for classification in the genus

Seven specimens of Rhynchodemus sylvaticus (Leidy) collected from a variety of localities in the US and having variously developed copulatory organs are believed to represent stages in the development of the copulatory apparatus. Four specimens were juveniles with under-developed male components, one specimen had a well-developed female atrium and small male component, and two specimens were mature with a male organ twice the size of the female part. In early stages, the male component had sperm ducts, seminal vesicle, and narrow atrium; more mature stages had a considerable elongated atrium with thick folds in its muscularized wall, a massive muscular bulbus; and a sigmoid ejaculatory duct opening into the large bulbar cavity. Morphological features of mature male copulatory organs in all species of the genus Rhynchodemus are basically similar whereas external body features (color and number of dorsal stripes) of these same species differ.     

The karyotypes of Dugesia species from Spain (Turbellaria,Tricladida)

Some species of Planarians, new to Spain, are recorded. Dugesia polychroa, D. sicula, D. iberica and D. gonocephala s. 1. have been investigated karyologically. The former possesses a diploid complement characteristic of the biotype A (2n = 8); the second is diploid with 2n = 18; diploidy and triploidy were found in sexual populations of D. iberica with n = 8. Triploidy occurred in all the asexual strains of the D. gonocephala group with a basic number of either 8 or 9. In this latter case B-chromosomes were occasionally found.     

Tracking and predation on earthworms by the invasive terrestrial planarian Bipalium adventitium (Tricladida, Platyhelminthes)

The potential ecological impact of exotic terrestrial planarians will be determined in part by their sensory abilities and predatory behavior. It has been suggested that these flatworms may only encounter their earthworm prey by chance, hence restricting the breadth of species they will feed upon and the number of microhabitats in which predator-prey interactions occur. We hypothesized that those flatworms that have already successfully invaded North America (genus Bipalium) actually detect and follow chemical trails of earthworms and possess the behavioral repertoire needed to feed on the prey in a range of microhabitats. We examined: (1) the tendency of Bipalium adventitium to follow chemical trails left by injured and un-injured earthworms; (2) the behavioral repertoire and predatory success of B. adventitium feeding on three earthworm species in subterranean tunnels; and (3) the response of flatworms to the reportedly defensive secretions of the earthworm Eisenia fetida in tunnels. B. adventitium detected and followed trails of earthworm mucus and secretions left by injured and un-injured earthworms. Flatworms followed trails on a range of substrates and pursued and captured three species of earthworms in subterranean tunnels, including individuals many times their mass. Although most behavior exhibited during underground attacks was similar to that reported for surface encounters, the flatworms also behaved in ways that blocked earthworm escape from tunnels. The flatworms were less successful at preying on E. fetida than on Lumbricus rubellus and Lumbricus terrestris in underground tunnels and showed some aversion to the secretions from E. fetida.     

Predation potential of three flatworm species (Platyhelminthes: Turbellaria) on mosquitoes (Diptera: Culicidae)

We conducted a field survey for flatworms to select species as potential biological control agents against Aedes aegypti and Culex pipiens (Diptera, Culicidae) breeding in artificial containers. Laboratory experiments were performed to determine the daily predation rate, differential predation on each mosquito larval instar, selective predation on either A. aegypti or C. pipiens, and predator tolerance to water from artificial containers. Girardia anceps (Tricladida, Paludicola, Dugesiidae), Mesostoma ehrenbergii and Bothromesostoma cf. evelinae (Rhabdocoela, Typhloplanoida, Typhloplanidae) were found in temporary puddles and permanent pools. In the laboratory, they killed between 52% and 100% of immature mosquitoes coexisting in the same habitat. No preference of flatworms for mosquito preys was detected. Predation rate was related to predator size and instar of preys. Girardia anceps and B. evelinae survived after a dry period and when re-flooding occurred, they laid eggs. Tolerance to water from artificial containers was highest in G. anceps and this species could be a suitable predator to reduce mosquito populations from artificial containers using an inoculative approach.