the azure-crowned hummingbird ( amazilia cyanocephala ) is a species of hummingbird in the family trochilidae .

it is found in belize , el salvador , guatemala , honduras , mexico , and nicaragua .

its natural habitat is subtropical or tropical moist montane forests .

azure - crowned hummingbird

perched individual giving alarm calls in presence of perched american kestrel nearby . toward the end of the recording , the american kestrel can briefly be heard calling when taking off , and the azure - crowned hummingbird follows him . recording unmodified . habitat open young pine forest , both birds perched 8 m above ground in 12 m tall pinus oocarpa , but in different trees . distance between hummingbird and kestrel 10 m .
perched on the lowest branch of a pine tree ( pinus oocarpa ) , recorded at 4 m distance . recording unmodified . pine - oak forest with a rich understory of flowering calliandra houstoniana , which had attracted during this time of year good numbers of hummingbirds to the site . the azure - crowned hummingbird is there year - round , though .
weller , a . a . & kirwan , g . m . ( 2018 ) . azure - crowned hummingbird ( amazilia cyanocephala ) . in : del hoyo , j . , elliott , a . , sargatal , j . , christie , d . a . & de juana , e . ( eds . ) . handbook of the birds of the world alive . lynx edicions , barcelona . ( retrieved from urltoken on 9 july 2018 ) .
html public
- / / w3c / / dtd xhtml 1 . 0 strict / / en
urltoken
thank you for taking the time to provide feedback on the iucn red list of threatened species website , we are grateful for your input .
del hoyo , j . , collar , n . j . , christie , d . a . , elliott , a . and fishpool , l . d . c . 2014 . hbw and birdlife international illustrated checklist of the birds of the world . volume 1 : non - passerines . lynx edicions birdlife international , barcelona , spain and cambridge , uk .
justification : this species has a very large range , and hence does not approach the thresholds for vulnerable under the range size criterion ( extent of occurrence < 20 , 000 km2 combined with a declining or fluctuating range size , habitat extent / quality , or population size and a small number of locations or severe fragmentation ) . the population trend is not known , but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion ( > 30 % decline over ten years or three generations ) . the population size is very large , and hence does not approach the thresholds for vulnerable under the population size criterion ( < 10 , 000 mature individuals with a continuing decline estimated to be > 10 % in ten years or three generations , or with a specified population structure ) . for these reasons the species is evaluated as least concern .
partners in flight estimate the total population to number 50 , 000 - 499 , 999 individuals ( a . panjabi in litt . 2008 ) .
to make use of this information , please check the < terms of use > .
authors : marîa del coro arizmendi , claudia i . rodríguez - flores , carlos a . soberanes - gonzález , tom johnson , and thomas s . schulenberg
arizmendi , m . d . c . , c . i . rodríguez - flores , c . a . soberanes - gonzález , t . johnson , and t . s . schulenberg ( 2013 ) .
) , version 1 . 0 . in neotropical birds online ( t . s . schulenberg , editor ) . cornell lab of ornithology , ithaca , ny , usa .
recording unmodified . habitat was a cleared hiking trail in pine - oak zone .
male peched in the understory . second growth cloud forest . normalized at - 3db . recording made with a tascam dr 100 mk ii , unidirectional internal mic . code : 170322 3160 amazilia cyanocephala song
understory of second growth cloud forest . normalized at - 3db . recording made with a tascam dr 100 mk ii , unidirectional internal mic . code : 170321 3152 amazilia cyanocephala calls
apparently a lek . two males perched exposed singing incessantly . habitat : understory of second growth cloud forest . code : invasi 2764 amazilia cyanocephala lek _ 0129
id certainty 90 % . ( archiv . tape 166 side b track 27 seq . b )
sonogram images © xeno - canto foundation . sonogram images share the same license terms as the recording they depict .
hbw alive contains information on descriptive notes , voice , habitat , food and feeding , breeding , movements , status and conservation plus a list of bibliographical references for this species account .
no flash player has been set up . please select a player to play flash videos .
a bird feeding on flowers , then at slow motion ( 50 % ) .
alberto lobato , ian hempstead , dusan m . brinkhuizen , ken havard , marc fasol , knut eisermann .
– e & s mexico ( s from s tamaulipas ) to e honduras and nc nicaragua .
song apparently undescribed , but perhaps is the fairly mellow series of strong chipping notes , . . .
inhabits pine and pine–oak forest , cloudforest and rainforest , edges of humid forest ; also . . .
varies with region ; in mexico , feb–aug ; in belize , jan–jul ; in guatemala , data on gonadal activity indicate jul–sept ; in . . .
some populations are sedentary , for instance in veracruz and san luis potosí ( mexico ) , . . .
not globally threatened ( least concern ) . cites ii . common in pine and pine - oak forests of the highlands of interior mexico , guatemala and honduras , rarer in cloudforest and . . .
only subscribers are able to see the bibliography . login or subscribe to get access to a lot of extra features !
only members are able to post public comments . to make the most of all of hbw ' s features , discover our subscriptions now !
as currently constituted , this genus is not monophyletic # r ; more thorough sampling of taxa required before a clearer picture can be presented . in hbw , species currently placed herein were spread out over six genera , with additional recognition of agyrtria , polyerata and saucerottia , and relocation of some species in leucippus and hylocharis .
get access to the contents of the hbw including all species accounts , family texts , plates , audiovisual links , updates and related resources .
also available : 2 - year subscription package : 55 . 90 € ( instead of 59 . 90 € ) 3 - year subscription package : 82 € ( instead of 89 . 85 € )
supporting members help us to develop and update the project more quickly and to reach more people by keeping prices down .
view more information , tracking references to their source ( when available on the internet ) .
also available : 2 - year subscription package : 82 . 5 € ( instead of 89 . 9 € ) 3 - year subscription package : 122 . 5 € ( instead of 134 . 85 € )
there is a registration fee of 20€ . this is a one - time only fee when you become a subscriber of hbw alive . you won’t pay it again as long as you renew your subscription before it expires .
if you represent an organization or institution , click here for more information on institutional subscriptions .
this map displays aggregated data from ibc and my birding ( anonymously ) ; markers do not indicate precise localities .
this species has a very large range , and hence does not approach the thresholds for vulnerable under the range size criterion ( extent of occurrence < 20 , 000 km2 combined with a declining or fluctuating range size , habitat extent / quality , or population size and a small number of locations or severe fragmentation ) . the population trend is not known , but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion ( > 30 % decline over ten years or three generations ) . the population size is very large , and hence does not approach the thresholds for vulnerable under the population size criterion ( < 10 , 000 mature individuals with a continuing decline estimated to be > 10 % in ten years or three generations , or with a specified population structure ) . for these reasons the species is evaluated as least concern .
recommended citation birdlife international ( 2018 ) species factsheet : amazilia cyanocephala . downloaded from urltoken on 09 / 07 / 2018 . recommended citation for factsheets for more than one species : birdlife international ( 2018 ) iucn red list for birds . downloaded from urltoken on 09 / 07 / 2018 .
html public
- / / w3c / / dtd xhtml 1 . 0 transitional / / en
urltoken
myavibase allows you to create and manage your own lifelists , and produce useful reports to help you plan your next birding excursion .
there are more than 12 , 000 regional checklists in avibase , offered in 9 different taxonomies , including synonyms more than 175 languages . each checklist can be viewed with photos shared by the birding community , and also printed as pdf checklists for field use .
there are a few ways by which you can help the development of this page , such as joining the flickr group for photos or providing translations of the site in addition languages .
reference : hist . nat . ois . - mouches [ lesson ] p . xlv
howard and moore 4th edition ( incl . corrigenda vol . 1 - 2 ) :
you must be logged in to view your sighting details . to register to myavibase click here .
avibase has been visited 263 , 293 , 475 times since 24 june 2003 . © denis lepage | privacy policy
< p > an evidence describes the source of an annotation , e . g . an experiment that has been published in the scientific literature , an orthologous protein , a record from another database , etc . < / p > < p > < a href =
/ manual / evidences
> more . . . < / a > < / p >
help pages , faqs , uniprotkb manual , documents , news archive and biocuration projects .
you are using a version of browser that may not display all the features of this website . please consider upgrading your browser .
< p > when browsing through different uniprot proteins , you can use the ‘basket’ to save them , so that you can back to find or analyse them later . < p > < a href = ' / help / basket ' target = ' _ top ' > more . . . < / a > < / p >
< p > this will take you to the blast page where you can edit options < / p > < p > < a href =
/ help / sequence - searches
> more . . < / a > < / p >
we ' d like to inform you that we have updated our privacy notice to comply with europe’s new general data protection regulation ( gdpr ) that applies since 25 may 2018 .


magilus antiquus , common name the magilus coral snail , is a species of sea snail , a marine gastropod mollusk in the family muricidae , the murex snails or rock snails .

magilus antiquus

magilus coral snail or magilus antiquus , vintage engraved illustration . dictionary of words and things - larive and fleury - 189
magilus coral snail or magilus antiquus , vintage engraved illustration . dictionary of words and things - larive and fleury - 1895
coralliophilidae » magilus antiquus , id : 345505 , shell detail « shell encyclopedia , conchology , inc .
home freshwater and marine image bank magilus antiquus l . : a , the adult , imbedded in coral , which has been broken away to show the tube ; . . .
species magilus fimbriatus a . adams accepted as coralliophila fimbriata ( a . adams , 1854 )
( of magilus antiquatus ) taylor , j . d . ( 1973 ) . provisional list of the mollusca of aldabra atoll . [ details ]
species magilus cumingii ( h . adams & a . adams , 1864 ) accepted as coralliophila cumingii ( h . adams & a . adams , 1864 )
two young shells were obtained alive in company with the galeropsis just mentioned . tryon ' s remark
that all the species that have been differentiated from m . antiquus must be regarded with suspicion ,
has guided my determination . nothing seems to be recorded of the distribution of this species in the central pacific . a specimen from the solomon islands is in this museum .
oliverio , m . ( 2008 ) . coralliophilinae ( neogastropoda : muricidae ) from the southwest pacific . in : héros , v . et al . ( ed . ) tropical deep - sea benthos 25 . mémoires du muséum national d ' histoire naturelle ( 1993 ) . 196 : 481 - 585 . ( look up in imis ) page ( s ) : 557 [ details ]
spencer , h . g . , marshall , b . a . & willan , r . c . ( 2009 ) . checklist of new zealand living mollusca . pp 196 - 219 . in : gordon , d . p . ( ed . ) new zealand inventory of biodiversity . volume one . kingdom animalia : radiata , lophotrochozoa , deuterostomia . canterbury university press , christchurch . [ details ]
kilburn , r . n . ( 1977 ) taxonomic studies on the marine mollusca of southern africa and mozambique . part 1 . annals of the natal museum , 23 , 173–214 . [ details ]
liu j . y . [ ruiyu ] ( ed . ) . ( 2008 ) . checklist of marine biota of china seas . china science press . 1267 pp . ( look up in imis ) [ details ] available for editors [ request ]
kilburn r . n . , marais j . p . & marais a . p . ( 2010 ) coralliophilinae . pp . 272 - 292 , in : marais a . p . & seccombe a . d . ( eds ) , identification guide to the seashells of south africa . volume 1 . groenkloof : centre for molluscan studies . 376 pp . [ details ]
eol content is automatically assembled from many different content providers . as a result , from time to time you may find pages on eol that are confusing .
to request an improvement , please leave a comment on the page . thank you !
html public
- / / w3c / / dtd xhtml 1 . 0 strict / / en
urltoken
the star system calculates the number of pieces that were handled by conchology , inc . in the last 15 years :
we want to point out that the star system is only very reliable for philippine shells only , as we handle very few foreign shells in general . as time goes , the system will become more and more performant .
enter your email address and we will send you an email with your username and password .
e - mail jecilia sisican if you do not receive your email with your username and password .
© 1996 - 2018 guido t . poppe & philippe poppe - conchology , inc . ( 0 . 002 seconds . )
html public
- / / w3c / / dtd html 4 . 01 transitional / / en
javascript is required to use this web site . please turn it on before proceeding .
html public
- / / w3c / / dtd xhtml 1 . 0 transitional / / en
urltoken
in : okutani , t . ( ed . ) , marine mollusks in japan . tokai university press , tokyo , 365 - 421 ( in japanese ) .
occurrence record in darwincore format ( elements of obis schema and some of dwc1 . 4 )
confused by a class within a class or an order within an order ? please see our brief essay .
to cite this page : myers , p . , r . espinosa , c . s . parr , t . jones , g . s . hammond , and t . a . dewey . 2018 . the animal diversity web ( online ) . accessed at https : / / animaldiversity . org .
disclaimer : the animal diversity web is an educational resource written largely by and for college students . adw doesn ' t cover all species in the world , nor does it include all the latest scientific information about organisms we describe . though we edit our accounts for accuracy , we cannot guarantee all information in those accounts . while adw staff and contributors provide references to books and websites that we believe are reputable , we cannot necessarily endorse the contents of references beyond our control .
this material is based upon work supported by the national science foundation grants drl 0089283 , drl 0628151 , due 0633095 , drl 0918590 , and due 1122742 . additional support has come from the marisla foundation , um college of literature , science , and the arts , museum of zoology , and information and technology services .
doctype html public
- / / w3c / / dtd html 4 . 0 transitional / / en
very cool . . . oliva amethysthina carnicolor ~ 38 . 6mm ~ philippine seashell
this amount includes applicable customs duties , taxes , brokerage and other fees . this amount is subject to change until you make payment . for additional information , see the global shipping program terms and conditions - opens in a new window or tab
this amount includes applicable customs duties , taxes , brokerage and other fees . this amount is subject to change until you make payment . if you reside in an eu member state besides uk , import vat on this purchase is not recoverable . for additional information , see the global shipping program terms and conditions - opens in a new window or tab
delivery time is estimated using our proprietary method which is based on the buyer ' s proximity to the item location , the shipping service selected , the seller ' s shipping history , and other factors . delivery times may vary , especially during peak periods .
any international shipping and import charges are paid in part to pitney bowes inc . learn more - opens in a new window or tab
international shipping and import charges paid to pitney bowes inc . learn more - opens in a new window or tab
international shipping paid to pitney bowes inc . learn more - opens in a new window or tab
any international shipping is paid in part to pitney bowes inc . learn more - opens in a new window or tab
this item will be shipped through the global shipping program and includes international tracking . learn more - opens in a new window or tab
there are 1 items available . please enter a number less than or equal to 1 .
* estimated delivery dates - opens in a new window or tab include seller ' s handling time , origin zip code , destination zip code and time of acceptance and will depend on shipping service selected and receipt of cleared payment - opens in a new window or tab . delivery times may vary , especially during peak periods .
qualifying purchases could enjoy no interest if paid in full in 6 months on purchases of $ 99 or more . other offers may also be available .
interest will be charged to your account from the purchase date if the balance is not paid in full within 6 months . minimum monthly payments are required . subject to credit approval . see terms - opens in a new window or tab
we expect full payment w / i 10 days . we accept paypal . if you are a bidder living outside the usa , s & h will be revised . thank you . barb p . s . we are happy to combine shipping for you . we do not ship to italy .
copyright © 1995 - 2018 ebay inc . all rights reserved . accessibility , user agreement , privacy , cookies and adchoice
most materials are located in the university of washington libraries . images were scanned by staff of the uw fisheries - oceanography library .
materials in the freshwater and marine image bank are in the public domain . no copyright permissions are needed . acknowledgement of the freshwater and marine image bank as a source for borrowed images is requested .
the university of washington libraries does not provide reproductions of this image . this record contains a citation for this image . if you want to use the scanned image , acknowledgement of the freshwater and marine image bank as a source for borrowed images is requested .
barnes ( albert h . ) photographs of western washington , ca . 1895 - 1920
boyd and braas photographs of seattle and washington state , ca . 1888 - 1893
cobb ( john n . ) photographs of the fishing industry , ca . 1897 - 1917
hegg ( eric a . ) photographs of alaska and the klondike , 1897 - 1901
lindsley ( lawrence denny ) photographs of washington state , ca . 1875 - 1971
meed ( william e . ) photographs of the yukon territory , ca . 1898 - 1907
morell ( karen l . ) africa , trinidad , and new orleans multimedia collection
peiser ( theodore e . ) photographs of washington state , ca . 1864 - 1910
sarvant ( henry m . ) photographs of washington state and the yukon , 1892 - 1912
van olinda ( oliver s . ) photographs of puget sound , 1880s - 1930s
waite ( alvin h . ) photographs of tacoma and washington state , 1892 - 1907
montfort , p . d . de 1810 . conchyliologie systématique , et classification méthodique des coquilles ; offrant leurs figures , leur arrangement générique , leurs descriptions caractéristiques , leurs noms ; ainsi que leur synonymie en plusieurs langues . ouvrage destiné à faciliter l ' étude des coquilles , ainsi que leur disposition dans les cabinets d ' histoire naturelle . coquilles univalves , non cloisonnées . tome second . - pp . [ 1 - 3 ] , 1 - 676 . paris . ( schœll ) .
you will be directed to the entry page of the digitized work . go to the page you need in the navigation system there .
the basic data of this taxon were entered by hand , consulting the original description , and following animalbase standard .
( of campulotus guettard , 1770 ) guettard j . e . ( 1770 ) . mémoires sur différentes parties des sciences et arts [ qui referme ] . . . deuxième mémoire , qui renferme la concordance des auteurs qui ont parlé des tuyaux marins fossiles , auxquels on a comparé ceux qui se pêchent actuellement dans la mer . classe des tuyaux marins . troisième mémoire . sur les erreurs où l ' on a été au sujet des tuyaux marins . paris , prault . 3 ( 544 ) : 71 . , available online at urltoken page ( s ) : 94 [ details ]
vaught , k . c . ; tucker abbott , r . ; boss , k . j . ( 1989 ) . a classification of the living mollusca . american malacologists : melbourne . isbn 0 - 915826 - 22 - 4 . xii , 195 pp . ( look up in imis ) [ details ]
( of campulotus guettard , 1770 ) bieler , r . ; petit , r . e . ( 2011 ) . catalogue of recent and fossil “worm - snail” taxa of the families vermetidae , siliquariidae , and turritellidae ( mollusca : caenogastropoda ) . zootaxa . 2948 , 1 - 103 . , available online at urltoken page ( s ) : 13 , 69 , 73 [ details ]
sorry , we just need to make sure you ' re not a robot . for best results , please make sure your browser is accepting cookies .
html public
- / / w3c / / dtd html 4 . 01 / / en
urltoken
in : the atoll of funafuti , ellice group : its zoology , botany , ethnology and general structure based on collections made by charles hedley of the australian museum , sydney , n . s . w .
the atoll of funafuti , ellice group : its zoology , botany , ethnology and general structure based on collections made by charles hedley of the australian museum , sydney , n . s . w .
authors : hesse , richard , 1868 - 1944 ; allee , w . c . ( warder clyde ) , 1885 - 1955 ; schmidt , karl patterson , 1890 - 1957
publisher : new york : j . wiley & sons , inc . ; london : chapman & hall , limited
click here to view book online to see this illustration in context in a browseable online version of this book .
please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work .
html public
- / / w3c / / dtd html 4 . 01 transitional / / en
urltoken
, select family and click on ' identification by pictures ' to display all available pictures in sealifebase for the family .
, select country and click on ' identification by pictures ' to display all available pictures in sealifebase for the country .
, select ecosystem and click on ' identification by pictures ' to display all available pictures in sealifebase for the ecosystem .
cfm script by , 30 . 11 . 04 , , php script by , 05 / 11 / 2010 , last modified by kbanasihan , 06 / 28 / 2010
if is associated with an alamy account you ' ll receive an email with instructions on how to reset your password .
enter your log in email address and well send you a link to reset your password .
if you want to use this image commercially and we ' ve indicated * that alamy doesn ' t have a release , you might need additional permission from the model , artist , owner , estate , trademark or brand . more information .
sorry , this image isn ' t available for this licence . please refer to the license restrictions for more information .
on the alamy prints site ( powered by art . com ) choose your frame , the size and finish of your photo .
enter your log in email address and we ' ll send you a link to reset your password .


the dryad shrew tenrec ( microgale dryas ) , also known as the tree shrew tenrec , is a species of mammal in the family tenrecidae .

it is endemic to madagascar .

its natural habitat is subtropical or tropical moist lowland forests .

it is vulnerable to extinction by habitat loss .

dryad shrew tenrec

a cowan’s shrew tenrec , microgale cowani , in captivity . © peter j . stephenson
dryad is a nonprofit repository for data underlying the international scientific and medical literature .
tenrecs with very narrow distributions or specific threats may need extra help . more research is required to confirm the distribution and abundance of poorly known shrew tenrec species ( e . g . dryad , montane and nasolo ' s shrew tenrecs ) . if they genuinely occur in only a handful of sites , conservation efforts will be needed to target their habitat .
tenrec diet is based on invertebrates . insects and their larvae are the most commonly consumed prey items . however , many of the larger species ( from talazac ' s shrew tenrec – microgale talazaci - to the tailless tenrec – tenrec ecaudatus ) sometimes take small vertebrates such as amphibians . two species have become very specialized : streaked tenrecs eat mostly soft - bodied invertebrates , with an apparent preference for earthworms ; large - eared tenrecs ( geogale aurita ) prefer termites they find inside dead wood . the aquatic tenrec feeds on a range of prey in its freshwater habitat , but favours aquatic insect larvae and crayfish .
the tenrecinae are spiny tenrecs . the largest species is the tailless tenrec , tenrec ecaudatus , which weighs up to 1 kg . it is as large as a rabbit , and is less spinescent than the other species . other spiny tenrecs are the two species of hedgehog tenrec ( setifer setosus and echinops telfairi ) and the two species of streaked tenrec ( hemicentetes semispinosus and h . nigriceps )
a lowland streaked tenrec , hemicentetes semispinosus . © l . e . olson & s . m . goodman
the potamogalinae are otter shrews which are found on mainland africa . many scientists now consider these animals as tenrecs . the giant otter shrew , potamogale velox , is widespread in the streams and rivers of central african forests , but the other two species have restricted distributions . the nimba otter shrew , micropotamogale lamottei , is found only in a small area around mount nimba on the borders of ivory coast , liberia and guinea , and the ruwenzori otter shrew , m . ruwenzorii , is found only between uganda and eastern drc . habitat loss , mining and fish traps threaten otter shrews across their range . ( see section “tenrecs in africa – the otter shrews” ) .
a number of predators are known or suspected to feed on tenrecs . these range from birds of prey and viverrid carnivores to snakes ; some small shrew tenrecs ( microgale spp . ) may even be attacked by larger species of their own genus .
eastern rain forest in madagascar is habitat for many tenrec species , yet much of it is being lost to provide land for agriculture such as these paddy fields in the north - east of the country . © peter j . stephenson
the geogalinae is a recently recognised sub - family , comprising the single species , geogale aurita ( the large - eared tenrec ) . it is a small species ( about 7g ) adapted for life in the arid south - west and specialised in a termite diet .
tenrecs are generally found in forest habitats . most species occur in the eastern rain forests , but a handful ( e . g . geogale , echinops ) are adapted to the arid spiny desert in the south - west of madagascar . the aquatic tenrec ( limnogale mergulus ) requires clear , running freshwater . some species - such as tailless tenrecs ( tenrec ecaudatus ) and streaked tenrecs ( hemicentetes ) - appear able to adapt easily to man - induced disturbance , and can survive in secondary forest or agricultural land . mole tenrecs ( oryzorictes ) have been found in rice fields .
the aquatic tenrec ( limnogale mergulus ) is the greatest cause for concern among conservationists . it is known from only 10 sites in madagascar and appears to be restricted to clear streams with abundant prey . siltation caused by widespread deforestation is expected to cause problems as it will reduce prey species . animals are also drowned in eel and crayfish traps .
the mammal was an early tenrec ; the island it had arrived on probably had no other mammals and so this early lineage evolved over generations to adapt its body shape to its environment . as a result of a process called
adaptive radiation
( made famous by darwin ' s finches on galapagos ) new species appeared , each physically suited for its niche , free of competition .
html public
- / / w3c / / dtd xhtml 1 . 0 transitional / / en
urltoken
traditionally included in the lipotyphla ( = insectivora sensu stricto ) . various molecular studies ( madsen et al . , 2001 ; murphy et al . , 2001 a , b ; springer et al . , 1999 ) and syntheses of morphological and molecular data ( asher et al . , 2003 ; liu et al . , 2001 ) support a clade containing tenrecs and golden moles , which stanhope et al . ( 1998 ) named afrosoricida . this name is inappropriate since this clade does not include soricids , and could lead to confusion with the soricid subgenus afrosorex hutterer , 1986 . noting that tenrecomorpha butler , 1972 may be a prior , and more explicit name for this clade following simpson’s ( 1945 ) guidelines for naming superfamial taxa , bronner et al . ( 2003 ) nevertheless accepted afrosoricida because this name is entrenched in the recent literature .
following simpson ( 1931 ) , the term
tenrecoid
has also been widely misused as a general name for a vaguely defined grouping of ( extinct and extant ) taxa characterized by zalambdodonty , even though it has become clear that some of these were not technically zalambdodont , and that zalambdodonty may have arisen independently several times ( e . g . broom , 1916 ) . this further militates against its stricter nomenclatorial use , even at taxonomic ranks below order .
the supraordinal affiliation of the afrosoricida remains controversial . molecular data strongly support an affinity within the afrotheria , whereas morphological data suggest a closer relationship to lipotyphlans . lipotyphlan monophyly , however , is only weakly supported by cladistic analyses of morphological data ( asher , 1999 ) and phylogenetic analyses of combined anatomical and molecular data strongly support the inclusion of afrosoricids within afrotheria ( asher et al . , 2003 ) .
mammal species of the world : a taxonomic and geographic reference ( book , 2005 ) [ worldcat . org ]
your web browser is not enabled for javascript . some features of worldcat will not be available .
your list has reached the maximum number of items . please create a new list with a new name ; move some items to a new or existing list ; or delete some items .
note : citations are based on reference standards . however , formatting rules can vary widely between applications and fields of interest or study . the specific requirements or preferences of your reviewing publisher , classroom teacher , institution or organization should be applied .
the e - mail address ( es ) field is required . please enter recipient e - mail address ( es ) .
the e - mail address ( es ) you entered is ( are ) not in a valid format . please re - enter recipient e - mail address ( es ) .
i thought you might be interested in this item at urltoken title : mammal species of the world : a taxonomic and geographic reference author : don e wilson ; deeann m reeder publisher : baltimore : johns hopkins university press , ©2005 . isbn / issn : 0801882214 9780801882210 0801882389 9780801882388 0801882397 9780801882395 oclc : 57557352
wilson and reeder ' s mammal species of the world is the classic reference book on the taxonomic classification and distribution of the more than 5400 species of mammals that exist today . the third edition includes detailed information on nomenclature and , for the first time , common names . each concise entry covers type locality , distribution , synonyms , and major reference sources . the systematic arrangement of
information indicates evolutionary relationships at both the ordinal and the family level . this indispensable reference work belongs in public and academic libraries throughout the world and on the shelf of every biologist who works with mammals .
- - publisher ' s website .
please choose whether or not you want other users to be able to see on your profile that this library is a favorite of yours .
this indispensable reference work belongs in public and academic libraries throughout the world and on the shelf of every biologist who works with mammals .
a uniquely valuable compendium of taxonomic and distributional data on the world ' s living and historically extinct mammalian species . contributors and editors alike deserve the thanks of all
add tags for
mammal species of the world : a taxonomic and geographic reference
.
you may have already requested this item . please select ok if you would like to proceed with this request anyway .
wilson and reeder ' s mammal species of the world is the classic reference book on the taxonomic classification and distribution of the more than 5400 species of mammals that exist today . the third edition includes detailed information on nomenclature and , for the first time , common names . each concise entry covers type locality , distribution , synonyms , and major reference sources . the systematic arrangement of information indicates evolutionary relationships at both the ordinal and the family level . this indispensable reference work belongs in public and academic libraries throughout the world and on the shelf of every biologist who works with mammals .
- - publisher ' s website .
worldcat is the world ' s largest library catalog , helping you find library materials online . learn more ››
don ' t have an account ? you can easily create a free account .
html public
- / / w3c / / dtd xhtml 1 . 0 strict / / en
urltoken
thank you for taking the time to provide feedback on the iucn red list of threatened species website , we are grateful for your input .
note : this is an amended assessment to correct the order of the assessors .
this species is listed as vulnerable under criterion b1ab ( iii ) . it has an extent of occurrence ( eoo ) of ca . 10 , 000 km
, it is known from fewer than 10 locations , and there is continuing decline in the extent and quality of its habitat .
it is threatened by deforestation and habitat fragmentation , through conversion to cultivated areas and general logging activities .
this species is known from only a few sites in northeastern madagascar . there is some doubt about a record from anjanaharibe - sud special reserve as it was collected from an owl pellet . it has been recorded between 500 and 940 m asl .
it is a poorly - known species that has only been recorded in the eastern lowland rain forests . it is possibly a semi - fossorial species which is believed to be forest dependent . the ecology of the species is not known .
it has been recorded from two protected areas : ambatovaky special reserve and anjanaharibe - sud special reserve . it has been recorded in the future protected area of makira . further studies are needed into the taxonomy , distribution , population , biology , ecology and threats to this species .
to make use of this information , please check the < terms of use > .
html public
- / / w3c / / dtd html 4 . 01 transitional / / en
urltoken
english - german online dictionary developed to help you share your knowledge with others . more information ! contains translations by tu chemnitz and mr honey ' s business dictionary ( german - english ) . thanks on that account ! links to this dictionary or to single translations are very welcome ! questions and answers
mammal species of the world : a taxonomic and geographic reference , 2nd ed . , 3rd printing
mammal species of the world : a taxonomic and geographic reference , 3rd ed . , vols . 1 & 2
with contributions by bernadette n . graham , adam p . potter , and mariana m . upmeyer
disclaimer : itis taxonomy is based on the latest scientific consensus available , and is provided as a general reference source for interested parties . however , it is not a legal authority for statutory or regulatory purposes . while every effort has been made to provide the most reliable and up - to - date information available , ultimate legal requirements with respect to species are contained in provisions of treaties to which the united states is a party , wildlife statutes , regulations , and any applicable notices that have been published in the federal register . for further information on u . s . legal requirements with respect to protected taxa , please contact the u . s . fish and wildlife service .
html public
- / / w3c / / dtd html 4 . 01 transitional / / en
this article will be permanently flagged as inappropriate and made unaccessible to everyone . are you certain this article is inappropriate ?
as part our commitment to scholarly and academic excellence , all articles receive editorial review .
copyright © world library foundation . all rights reserved . ebooks from project gutenberg are sponsored by the world library foundation , a 501c ( 4 ) member ' s support non - profit organization , and is not affiliated with any governmental agency or department .
the following material is adapted from an article published in 2007 : stephenson , p . j . ( 2007 ) . mammals from another time : tenrecs in madagascar . africa geographic , march 2007 , vol 15 ( 2 ) : 34 - 41 .
the island continent of madagascar was part of a large land mass that broke away from africa some 165 million years ago . as tectonic plates shifted subtly on the earth ' s surface , the land mass moved out slowly into the indian ocean . other chunks of land later floated off to leave the island the size and shape we now know , situated 400 km off the mozambique coast for the last 80 millions years .
at that time the island was probably a mix of habitats much as it is today : thick rain forest on the east coast , deciduous forests in the west , deserts with spiny succulent plants in the south - west , and amid the forests of the high plateau a mosaic of grasslands grazed by giant tortoises and walked upon by 3 - 4 metre tall elephant birds . mammals had evolved from therapsid reptiles and were spreading across africa , but none had appeared on madagascar , as its reptiles were from a different stock .
what happened next is only conjecture , but sometime around 60 million years ago a small mammal - perhaps no more than 5 or 6 g in weight with a primitive body plan and physiology - was washed out to sea from africa . perhaps it was on a log that had fallen into a river from the coastal forest of what is now kenya . currents and winds moved the mammal across the channel until it arrived on madagascar . perhaps the founder was joined by others ; perhaps it was a pregnant female . whatever the case , the animals multiplied . and then evolution kicked in !
very few other mammals ever made the same journey . eventually rodents , a mongoose - like carnivore and a primitive primate crossed the channel and gave rise to species found nowhere else on earth . a pygmy hippopotamus also crossed but madagascar never saw cats , dogs or large herbivores .
most tenrecs died out on mainland africa and are known only from fossil records ; all except one small lineage that evolved to fill a specialized aquatic niche - the otter shrews ( see section
tenrecs in africa – the otter shrews
) . however , tenrecs still inhabit madagascar today in an abundance and diversity not seen in any other mammalian family .
but then there are species not just from another time , but also from another world . streaked tenrecs ( hemicentetes ) are so unique nothing like them ever evolved elsewhere . their black and pale striped body is covered in spines , with a head crest of quills that can be erected . when irritated the animal makes head butting movements , trying to leave the barbed spines in the nose of its aggressor . a patch of spines on the back form what is known as a stridulating organ - the spines can rub together and produce a type of ultrasound that keeps the family groups together . tongue clicks made by the animals are thought to be a type of echolocation , perhaps used for hunting prey .
in spite of their many adaptations , tenrecs still exhibit a number of characteristics which make them distinct from other small mammals and which were probably typical of the earliest mammals . such traits include nocturnal activity patterns , small body size , the retention of a cloaca as a common uro - genital opening , abdominal testes , poor eyesight and a dependence on their sense of smell and hearing . they are also considered primitive physiologically , since all species have relatively low body temperatures and metabolic rates relative to their body size , and several specied enter torpor regularly .
tenrecs are probably most closely related to golden moles ( chrysochloridae ) . along with golden moles , scientists now consider tenrecs part of the afrotheria , a grouping of african mammals with evolutionary connections that also contains the aardvark , sengis ( or elephant - shrews ) , hyraxes , elephants and sea cows .
six malagasy tenrecs appear in the iucn red list of 2006 . endangered species are considered more threatened than vulnerable species . data deficient species require more information before an assessment can be completed .
special attention needs to be paid urgently to aquatic tenrecs . research should be conducted into their habitat needs and factors affecting their distribution . land - use and fishing practices may need to be changed in areas where they occur . although small mammals are often neglected in large conservation programmes , aquatic tenrecs would make ideal flagship species for integrated forest and freshwater conservation programmes in eastern madagascar . work to conserve forest habitats and maintain clear , unsilted streams will benefit a range of other plant and animal life as well as aquatic tenrecs .
tenrecs are a unique and diverse family of mammals , from another world and another time . they make up a significant component of madagascar’s faunal diversity and no doubt hold the answer to many scientific questions on the evolution and adaptation of mammals . let ' s hope that current conservation efforts ensure that their time is not up yet !
html public
- / / w3c / / dtd html 4 . 0 transitional / / en
javascript is disabled for your browser . some features of this site may not work without it .
goodman , steven m . raxworthy , christopher j . maminirina , claudette p . olson , link e .
latest build fri , 29 jun 2018 05 : 39 : 03 utc . served by aws - prod


dugesia ( pronounced , d ( y ) üˈjēzh ( ē ) ə ) is a genus of dugesiid triclad that contains some common representatives of the class turbellaria .

these common flatworms are found in freshwater habitats of africa , europe , middle east , asia and australia .

dugesia is best known to non-specialists because of its regeneration capacities .

dugesia is the type genus of the family dugesiidae .

dugesia

on the taxonomic status of dugesia gonocephala and dugesia subtentaculata ( turbellaria , tricladida , paludicola ) .
a new freshwater planarian , dugesia japonica , commonly but erroneously known as dugesia gonocephala ( dugès ) .
a subterminal opening of the ejaculatory duct , as found in dugesia superioris , occurs in no less than 26 species of dugesia : dugesia bakurianica porfirjeva , 1958 , dugesia biblica benazzi & banchetti , 1972 , dugesia leporii pala et al . , 2000 , and dugesia sicula lepori , 1948 , from the western palaearctic ; dugesia aethiopica stocchino et al . , 2002 , dugesia arabica harrath & sluys , 2013 , dugesia astrocheta marcus , 1953 , dugesia lanzai banchetti & del papa , 1971 , dugesia lamottei de beauchamp , 1952 , dugesia neumanni ( neppi , 1904 ) and dugesia myopa de vries , 1988b from the afrotropical region ; the other 15 species are distributed in the oriental region , eastern palaearctic and australasian region , viz . dugesia andamanensis ( kaburaki , 1925 ) , dugesia austroasiatica kawakatsu , 1985 , dugesia batuensis ball , 1970 , dugesia bengalensis kawakatsu , 1983 , dugesia burmanensis ( kaburaki , 1918 ) , dugesia deharvengi kawakatsu & mitchell , 1989 , dugesia indica kawakatsu , 1969 , dugesia indonesiana kawakatsu , 1973 , dugesia japonica ichikawa & kawakatsu , 1964 , dugesia leclerci kawakatsu & mitchell , 1995 , dugesia lindbergi de beauchamp , 1959 , dugesia nannophallus ball , 1970 , dugesia novaguineana kawakatsu , 1976 , dugesia tamilensis kawakatsu , 1980 , and dugesia uenorum kawakatsu & mitchell , 1995 . however , in all of these species the ejaculatory duct is ventrally displaced , except for dugesia bakurianica in which the ejaculatory duct is central . therefore , a dorsal course of the ejaculatory duct and a subterminal opening of the duct represents a new diagnostic combination in the genus dugesia .
descrizione di dugesia biblica , nuova microspecie del “gruppo dugesia gonocephala ” trovata nel fiume giordano ( israele ) .
dugesia hepta , nuova specie di planaria d’acqua dolce di sardegna appartenente alla superspecie dugesia gonocephala ( dugès ) ( turbellaria , tricladida ) .
eduard solà marked
file : dugesia artesiana 3054 . jpg
as trusted on the
dugesia artesiana sluys & grant , 2007
page .
geographic distribution of dugesia superioris ( indicated by an asterisk ) and dugesia sp . nmnh 55294 ( indicated by black diamond ) in the lake ohrid region .
taxonomy and geographical distribution of dugesia japonica and d . ryukyuensis in the far east
identification and characterization of a novel multifunctional placenta specific protein 8 in dugesia japonica .
eduard solà marked
file : dugesia artesiana 3054 . jpg
as hidden on the
dugesia artesiana sluys & grant , 2007
page . reasons to hide : duplicate
switch from asexual to sexual reproduction in the planarian dugesia ryukyuensis . - pubmed - ncbi
descrizione della planaria dugesia lanzai , n . sp . del kenya ( africa ) .
descrizione di dugesia sicula , nuova specie di triclade d’acqua dolce dei dintorni di catania .
a review of chromosomal variation in dugesia japonica and d . ryukyuensis in the far east
structural analysis of n - glycans of the planarian dugesia japonica . - pubmed - ncbi
regeneration in an evolutionarily primitive brain - - the planarian dugesia japonica model . - pubmed - ncbi
production of asexual and sexual offspring in the triploid sexual planarian dugesia ryukyuensis . - pubmed - ncbi
a molecular cytogenetic comparison of planarians from the ‘ dugesia gonocephala group’ ( platyhelminthes , tricladida ) .
on the species of the dugesia gonocephala group ( platyheminthes , turbellaria , tricladida ) from greece .
a new species of freshwater planarian belonging to the genus dugesia ( platyhelminthes , tricladida ) from sardinia .
identification and characterization of a novel multifunctional placenta specific protein 8 in dugesia japonica . - pubmed - ncbi
how often does reproduction occur ? dugesia tigrina can mate and / or reproduce many times in its life .
the dugesia can reproduce sexually , and all dugesia are hermaphrodites . two dugesia will pair up and fertilize each other ' s eggs . those eggs are then released in a cocoon . if there is not another dugesia present , one can reproduce asexually through a process called transverse fission . the organism will pull itself in half and the tail portion will regenerate a new head , and the head portion will regenerate a new tail . this process can be replicated in the lab by using a razor blade or scalpel to cut the dugesia in half . in a couple of weeks , you should have two dugesia swimming around in your petri dish .
ichikawa , a . & kawakatsu , m . , 1964 . a new freshwater planarian , dugesia japonica , commonly but erroneously known as dugesia gonocephala ( dugès ) . annot . zool . japon , 37 : 185–194 .
switching from asexual to sexual reproduction in the planarian dugesia ryukyuensis : bioassay system and basic description of sexualizing process .
the genus dugesia in australia , with its phylogenetic analysis and historical biogeography ( platyhelminthes , tricladida , dugesiidae ) .
stocchino ga , manconi r . overview of life cycles in model species of the genus dugesia ( platyhelminthes : tricladida )
a synopsis of the nominal species of the subgenus dugesia ( platyhelminthes , tricladida , paludicola ) from africa and madagascar .
african planarians : dugesia aethiopica sp . n . ( platyhelminthes , tricladida ) from lake tana ( nw ethiopia ) .
teshirogi , w . & itagaki , g . , 1965 . the chromosomes of dugesia species , a japanese freshwater planarian known as dugesia gonocephala . zool . mag . ( tôkyô ) , 74 : 38–45 . ( in japanese with english summary )
switching from asexual to sexual reproduction in the planarian dugesia ryukyuensis : change of the fissiparous capacity along with the sexualizing process .
reproductive strategies , karyology , parasites , and taxonomic status of dugesia populations from yemen ( platyhelminthes , tricladida , dugesiidae ) .
fluvial basin history in the northeastern mediterranean underlies dispersal and speciation patterns in the genus dugesia ( platyhelminthes , tricladida , dugesiidae ) .
eduard solà marked
file : daborensisdistribution . jpg
as trusted on the
dugesia aborensis ( whitehouse , 1913 )
page .
kenk , r . , 1940 . the reproduction of dugesia tigrina ( girard ) . am . nat . , 74 : 471–475 .
that kenk ( 1978 ) identified his dugesia material from ohrid ( nmnh 55294 ) as dugesia gonocephala is hardly surprising in view of the fact that at that time many european populations were assigned to dugesia gonocephala sensu lato . the precise anatomy of dugesia gonocephala sensu stricto was only resolved by de vries and ball ( 1980 ) and de vries ( 1984a , 1986 ) . a comparison with kenk’s specimen quickly learns that this animal does not conform to dugesia gonocephala because it does not exhibit the muscular ridges , the elongated penis papilla , or the two penial folds ( cf . de vries and ball 1980 , de vries 1984a ) . in the presence of a small dorsal penial fold and a central ejaculatory duct the animal resembles dugesia benazzii lepori , 1951 , dugesia elegans de vries , 1984 , dugesia taurocaucasica ( livanov , 1951 ) and dugesia effusa , the latter recently described from the greek island chios ( sluys et al . in prep . ) . dugesia benazzii from corsica and sardinia is characterized by a pointed diaphragm and a penial fold , the position of which is variable but which is usually located dorsally ; the size of the penial fold is also variable ( lepori 1951 , de vries 1984b ) . in dugesia benazzii ectal reinforcement is restricted to the region of the oviducal openings , the latter being symmetrically arranged . in contrast , in the nmnh 55294 specimen the oviducts open asymmetricaly into the bursal canal , while the ectal reinforcement extends further on the bursal canal .
eduard solà marked
file : d aborensis . jpg
as trusted on the
dugesia aborensis ( whitehouse , 1913 )
page .
dugesia superioris . holotype zma v . pl . 7153 . 1 , sagittal reconstruction of the copulatory apparatus ( anterior to the left ) .
a karyological study on populations of dugesia gonocephala s . l . ( turbellaria , tricladida ) . italian journal of zoology 66 : 245–253 .
dugesia deharvengi sp . n . , a new troglobitic freshwater planarian from tham kubio cave , thailand ( turbellaria ; tricladida ; paludicola ) .
molecular barcoding and phylogeography of sexual and asexual freshwater planarians of the genus dugesia in the western mediterranean ( platyhelminthes , tricladida , dugesiidae ) .
endemic freshwater planarians of sardinia : redescription of dugesia hepta ( platyhelminthes , tricladida ) with a comparison of the mediterranean species of the genus .
a karyological study by deri et al . ( 1999 ) identified for the pogradec population a complement of 24 standard chromosomes with one b - chromosome , suggesting a tri - ploid condition with a haploid number of n = 8 . moreover , their karyometric analysis indicated a probably aneutriploid condition , due to a constant excess of small , medium - sized chromosomes . a haploid number with n = 8 represents the most common chromosome number among dugesia species . dugesia superioris shares the tri - ploid condition with a haploid number of n = 8 with only a few other species from the western palaearctic region , viz . dugesia benazzii lepori , 1951 , dugesia etrusca benazzi , 1946 , dugesia liguriensis de vries , 1988a , and dugesia subtentaculata ( cf . benazzi and benazzi - lentati 1976 , ribas 1990 , pala 1993 , cf . lázaro et al . 2009 ) .
saccomanno , r . 2014 .
dugesia tigrina
( on - line ) , animal diversity web . accessed july 09 , 2018 at urltoken
further contributions to the taxonomy and biogeography of the subgenus dugesia ( platyhelminthes : tricladida : paludicola ) in the mediterranean region and the middle east .
kawakatsu , m . , teshirogi , w . , ôgawara , g . & tarui , y . , 1965 . photographic gleanings of planarians . i . dugesia japonica ichikawa et kawakatsu and dugesia gonocephala ( dugès ) . collect . & breed . ( tôkyô ) , 27 : 330–335 . ( in japanese )
switching from asexual to sexual reproduction in the planarian dugesia ryukyuensis : change of the fissiparous capacity along with the sexualizing p . . . - pubmed - ncbi
bessho y , ohama t , osawa s . planarian mitochondria i . heterogeneity of cytochrome c oxidase subunit i gene sequences in the freshwater planarian , dugesia japonica .
tcen - 49 , a monoclonal antibody that identifies a central body antigen in the planarian dugesia ( girardia ) tigrina . implications for pattern formation and positional signalling mechanisms
tcav - 1 , a monoclonal antibody specific to epithelial pharyngeal cells in the planarian dugesia ( girardia ) tigrina . application to pattern formation of the pharynx during regeneration
eduard solà marked
file : d aborensis . jpg
as hidden on the
dugesia aborensis ( whitehouse , 1913 )
page . reasons to hide : duplicate
for the genus dugesia a dorsal course of the ejaculatory duct was reported for the first time by stocchino et al . ( 2005 ) for the endemic sardinian species dugesia hepta pala , casu & vacca , 1981 . however , in this species the opening of the duct is located laterally on the right side , near the tip of the penis papilla . moreover , this species is characteri - zed by a ventro - lateral penial fold , which is absent in the new species . dugesia superioris therefore represents the second species of the genus showing a dorsal course of the ejaculatory duct . further , another important difference between dugesia hepta and dugesia superioris is the haploid chromosome number , which counts n = 7 in the former ( pala et al . 1981 ) and n = 8 in the latter ( deri et al . 1999 , see below ) .
to cite this page : saccomanno , r . 2014 .
dugesia tigrina
( on - line ) , animal diversity web . accessed july 09 , 2018 at urltoken
kenk , r . , 1941 . induction of sexuality in the asexual form of dugesia tigrina ( girard ) . j . exp . zool . , 87 : 55–69 .
therefore , the dugesia specimen nmnh 55294 may well represent a new species . however , on the basis of only the presently available material we refrain from describing it as new . furthermore , the asymmetrical openings of the vasa deferentia into the seminal vesicle of this animal represents a highly unusual condition for a species of dugesia and needs to be checked on additional material .
the penial fold of dugesia taurocaucasica is considerably larger than the one in nmnh 55294 , while the fold is also traversed by the abundant secretion of cyanophilic glands , which discharge through the lining epithelium of the penial fold . furthermore , in dugesia taurocaucasica the ectal reinforcement layer on the bursal canal extends for a considerable distance towards the copulatory bursa ( porfirjeva and dyganova 1987 ) .
reexamination of freshwater planarians found in tanks of tropical fishes in japan , with a description of a new species , dugesia austroasiatica sp . n . ( turbellaria ; tricladida ; paludicola ) .
sulle caratteristiche morfologiche e sulla posizione sistematica della planaria di sardegna e corsica già ascritta a dugesia gonocephala ( dugès ) . atti società toscana di scienze naturali 58 ( b ) : 1–22 .
pattee , e . , 1970 . coefficients thermiques et écologie de quelques planaires d ' eau douce . 4 . la reproduction de dugesia gonocephala . ann . limnol . 6 : 293–304 .
kawakatsu , m . , oki , i . , tamura , s . & sugino , h . , 1976b . studies on the morphology , karyology and taxonomy of the japanese freshwater planarian dugesia japonica ichikawa et kawakatsu , with a description of a new subspecies , dugesia japonica ryukyuensis subspec . nov . bull . fuji women ' s coll . , no . 14 , ser . ii : 81–126 .
sugino , h . , 1969 . collecting , breeding and experiments of a common japanese freshwater planarian , dugesia japonica ( with annotations and an appendix written by m . kawakatsu : on the physiological races of
dugesia elegans from rhodes differs from nmnh 55294 in the presence of a much larger seminal vesicle , a stubbier diaphragm , and the situation that its bursal canal epithelium is infranucleated ( de vries 1984a ) .
tamura , t . , yamayoshi , t . , oki , i . & kawakatsu , m . , 1979 . karyological and taxonomic studies of dugesia japonica ichikawa et kawakatsu . ii . chromosomes of dugesia japonica japonica collected from eighteen localities in japan . proc . jap . soc . syst . zool . , no . 17 : 1–14 ( + pls . 1–2 ) . ( in japanese with english summary )
an asexual population of dugesia sp . was collected in 2006 by r . manconi from voskopojë , an albanian locality situated south - west of lake ohrid . unfortunately , we have been unable to ascertain the taxonomic status of this population due to the lack of sexual specimens ( stocchino and manconi , pers . obs . ) . however , according to the phylogeographic analysis of lázaro et al . ( 2009 ) this population is molecularly identical to the pogradec population and therefore should be assigned also to dugesia superioris . it is noteworthy that the voskopojë locality is outside of the ohrid basin and therefore signals a wider distribution of dugesia superioris .
the planarian does not have gills or lungs , it obtains its oxygen by simple diffusion over its flat body . the dugesia cannot survive outside of the water , so biologists studying it must make sure that the specimen has plenty of water that is aerated . the dugesia does have an excretory system to remove wastes . tiny cells , called flame cells , line the lateral edge of the organism and function to remove waste .
more recently , a phylogeographic analysis of two albanian populations , one from pogradec and the other from voskopojë ( populations 30 and 31 , respectively in lázaro et al . 2009 ) , revealed that they belong to the same clade , which is well - separated from other species and populations of dugesia in the western mediterranean region , thus pointing to a new species ( lázaro et al . 2009 ) . in a second study , which included other and more eastern mediterranean species of dugesia , the population from pogradec ( population 15 in solà et al . 2013 ) also sat on its own branch , separate from all other populations of dugesia examined .
these are planarian worms , a type of flatworm in the phylum platyhelminthes and the class turbellaria . they are very common classroom organisms , with a simple body plan . the species in the photo here is dugesia subtentaculata .
the species dugesia effusa differs from nmnh 55294 in the presence of a short , valve - like diaphragm , a large intrabulbar seminal vesicle , a highly glandular penis papilla , and symmetrical oviducal openings into the bursal canal .
tamura , s . , yamayoshi , t . , oki , i . , murayama , h . & kawakatsu , m . , 1978 . karyological and taxonomic studies of dugesia japonica ichikawa et kawakatsu . i . chromosomes of the animals of dugesia japonica japonica collected from five localities in the central part of honshû and shikoku , japan . ibid . , no . 15 : 8–18 ( + pls . 1–2 ) . ( in japanese with english summary )
hirose , e . , katô , f . & sugino , h . , 1974 . chromosomes of freshwater planarian , dugesia japonica , ii . zool . mag . ( tôkyô ) , 83 : 442 . ( in japanese )
kawakatsu , m . , 1975 . problems on the morphological variation and the taxonomic position of a japanese freshwater planarian , dugesia japonica ichikawa et kawakatsu . zool . mag . ( tôkyô ) , 84 : 444 . ( in japanese )
tanaka , i . , 1965 . observation on the breeding of dugesia japonica ichikawa et kawakatsu from okinawa ( with an appendix written by m . kawakatsu ) . collect . & breed . ( tôkyô ) , 27 : 458–459 . ( in japanese )
okugawa , k . i . , 1957 . an experimental study of sexual induction in the asexual form of japanese freshwater planarian , dugesia gonocephala ( dugès ) . ibid . , ser . b , no . 11 : 8–27 ( + pls . 1–6 ) .
sugino , h . , hirose , e . & katô , f . , 1973 . the chromosomes of a japanese freshwater planarian , dugesia japonica ichikawa et kawakatsu . nature study ( ôsaka ) , 19 , no . 4 : 41–43 . ( in japanese )
okugawa , k . i . , 1955 . on the supernumerary sexual organs of dugesia gonocephala ( dugès ) , induced by the low temperature . bull . kyoto gakugei univ . , ser . b , no . 6 : 1–14 ( + pls . i–ii ) .
the dugesia does have a simple nervous system that includes a ganglia located in its anterior region to serve as a brain . as such , the dugesia exhibits the trait of cephalization , where the majority of its sense organs are located in the anterior region . it has a triangular head with two prominent eyespots . upon closer inspection of the eyes , you can see that they have a curious cross - eyed expression to them . the presence of the two eyes and lateral horns on the head indicate that the planarian has bilateral symmetry .
the planarian , dugesia dorotocephala ( woodworth ) , was studied in the laboratory and field as a predator of all developmental stages of culex peus speiser . reproduction by transverse fission was accelerated by higher feeding rates and probably by crowding . decreased feeding in culture could be offset by increasing the density of dugesia . experimental field populations of culex larvae were reduced by 90 + % in 26 days during july and august , 1973 . mucus secretions effectively immobilized prey larvae and their body fluid was consumed . mucus was also used to produce cemented sand anchors for attachment to larvae and pupae . group feeding without internecine activity was observed whereby as many as 12 dugesia collectively ensnarled a single prey . field and laboratory observations indicated optimum temperatures for feeding and reproduction were 20–26°c . feeding ceased above 29°c ; mortality ensued at 30°c .
dugesia is a genus of dugesiidae freshwater flatworms that includes around 75 species , all of them with a similar external appearance : triangle - shaped head with two eyes , and an elongated body . the different species are classified on the basis of the morphology of their copulatory apparatus .
boddington , m . t . & mettrick , d . f . , 1974 . the distribution , abundance , feeding habits and population biology of the immigrant triclad , dugesia polychroa ( platyhelminthes : turbellaria ) in toronto harbour , canada . j . anim . ecol . 43 : 681–699 .
dugesia superioris differs from its congeners in particular in ( a ) the dorsal course of the ejaculatory duct , with its sub - terminal opening , ( b ) the asymmetrical openings of the oviducts into the bursal canal , and ( c ) the openings of vasa deferentia at about halfway along the seminal vesicle .
dugesia superioris is characterized by the presence of the following features : dorsal course of the ejaculatory duct ; subterminal opening of the ejaculatory duct ; asymmetrical openings of the oviducts into the bursal canal ; openings of vasa deferentia at halfway along the seminal vesicle ; plump penis papilla ; small diaphragm ; triploid chromosome complement of 24 + 1b - chromosomes .
kawakatsu , m . , oki , i . , tamura , s . , yamayoshi , t . & takahashi , n . , 1980 . morphological , karyological and taxonomic studies of dugesia japonica ichikawa et kawakatsu from the tsushima islands . proc . jap . soc . syst . zool . , no . 19 : 1–10 ( + pls . 1–2 ) .
oki , i . , tamura , s . , kawakatsu , m . & sugino , h . , 1976 . morphological and karyological reexamination of the taxonomy of the freshwater planarian dugesia japonica , i . chromosomal analysis of the animals from different localities in japan and korea . zool . mag . ( tôkyô ) , 85 : 507 . ( in japanese )
dugesia superioris . photomicrographs of the copulatory apparatus . a holotype zma v . pl . 7153 . 1 , sagittal section showing the penis bulb and the penis papilla with the ejaculatory duct b paratype cgas pla 6 . 3 , transverse section of the penis papilla and the ejaculatory duct surrounded by numerous glands c paratype cgas pla 6 . 3 , transverse section of the bursal canal .
oki , i . , tamura , s . , yamayoshi , t . , kawakatsu , m . , hauser , j . & friedrich , s . m . g . , 1980 . karyological and taxonomic studies of freshwater planarians in brazil . ii . chromosomes of dugesia species from south brazil . zool . mag . ( tôkyô ) , 89 : 628 . ( in japanese )
okugawa , k . i . & kawakatsu , m . , 1954a . studies on the fission of japanese freshwater planaria , dugesia gonocephala ( dugès ) . i . comparative studies on fission rates and frequencies of sexual and asexual races influenced by temperatures , starvation and distilled water . ibid . , ser . b , no . 4 : 25–34 . ( in japanese with english summary )
kawakatsu , m . , oki , i . , tamura , s . & sugino , h . , 1976a . morphological and karyological reexamination of the taxonomy of the freshwater planarian dugesia japonica , ii . considerations about the subdivision of the species into two subspecies , with special reference to their subspeciations and phylogenetical problems . zool . mag . ( tôkyô ) , 85 : 508 . ( in japanese )
free - living flatworms like the planaria are grouped into the class turbellaria . the most common species studied in the lab is the brown planaria , dugesia . the animal has an acoelomate body ( no internal cavity to hold organs ) , no anus and lacks a circulatory system . most are scavengers and will eat other animals that have sank to the bottom of their ponds , hence why you can use liver to capture them .
kawakatsu , m . , oki , i . , tamura , s . , yamayoshi , t . , hauser , j . & friedrich , s . m . g . , 1980 . karyological and taxonomic studies of freshwater planarians in brazil . i . review of the previous studies , with special reference to the taxonomy of dugesia species from south brazil . zool . mag . ( tôkyô ) , 89 : 628 . ( in japanese )
a new species of the genus dugesia is described from the lake ohrid region in the western part of the balkan peninsula , forming the first fully documented species description for this genus in the ohrid area . the morphological species delimitation is supported by complementary molecular , karyological , and cytogenetic data available from the literature . therefore , species delineation is based on a truly integrative approach . further , a short account on the degree of freshwater planarian endemicity in the ohrid region is provided .
in this paper we report on a new species of freshwater planarian of the genus dugesia , forming the first fully documented species description for this genus in the ohrid area . our morphological species delimitation was supported by complementary molecular , karyological , and cytogenetic data available from the literature . therefore , our species delineation is based on a truly integrative approach . further , we provide a short account on the biogeographical patterns in freshwater planarians and their degree of endemicity in the ohrid region .
kawakatsu , m . , 1971 . problems on the morphological variation and the physiological races of a japanese freshwater planarian , dugesia japonica ichikawa et kawakatsu . in : eds . kawakatsu , m . & iba , m . , comm . compil . sci . papers publ . occ . retir . prof . hisao sugino at the age of sixtyfive , ser . turbellarians , biol . lab . ôsaka kyôiku univ . , ôsaka , pp . 43–52 . ( in japanese with english summary )
studies on the phylogeny of dugesia ( sluys et al . 1998 and references therein ) considered the asymmetrical penial papilla to constitute an important taxonomic feature . however , this asymmetry related to the apomorphic presence of a ventral ejaculatory duct . our present study shows that in future analyses this asymmetry needs to be specified by adding a third character state to character ( 1 ) ( sluys et al . 1998 , p . 277 and table ii ) , i . e . ejaculatory duct located dorsally .
the pogradec population had already been subjected to karyological , cytogenetic , and phylogeographic studies before anything was known about the anatomy of the specimens ( see above ) . all of these analyses pointed to a situation that this dugesia population differs considerably from congeneric populations . therefore , it was unsurprising that the anatomy of the pogradec animals suggested also that they represent a new species . as a result of the cumulation of the evidences from these independent datasets , the present delineation of the new species is based on a truly integrative approach to taxonomy .
a molecular cytogenetic comparison of several species and populations of the genus dugesia revealed that these planarians from pogradec besides two telomeric nor loci , also have a ribosomal site located in an intercalated position on the long arm of one of the largest chromosomes ( batistoni et al . 1999 ) . this peculiar condition differs from other planarian taxa , in which 18s + 28s rrna genes appeared preferentially located on telomeric regions of medium - sized chromosomes , and was interpreted by the authors as a structural chromosomal rearrangement , such as a paracentric inversion , suggesting a case of speciation .
in conclusion , it appears that d . sicula has reached a large proportion of the area of its potentially favourable distribution in the mediterranean basin , being a remarkable case of a broad colonisation , in extreme contrast with the rest of mediterranean dugesia species , with all of them being endemic or with very restricted distributions . d . sicula expansion is now limited to spreading to new freshwater basins within the areas it currently inhabits . however , future changes increasing the temperature , such as those predicted by climate change hypothesis , could expand its fitted area to more northern and interior areas .
dendrocoelum adenodactylosum is very common in the lake , in its tributary streams and springs and also in lake prespa , a nearby lake southeast of lake ohrid that is a major water supplier for the latter . six species are found in surrounding streams and springs and do not occur in the lake proper , viz . dugesia superioris , dendrocoelum jablanicense ( stanković & komárek , 1927 ) , schmidtea lugubris ( schmidt , 1861 ) , crenobia alpina montenigrina ( mrázek , 1904 ) , planaria torva ( müller , 1774 ) , and polycelis tenuis ijima , 1884 . dendrocoelum jablanicense is endemic of the lake ohrid region , while the others concern widespread species .
a review of previous studies on the taxonomy , karyology and chorology of a polymorphic species dugesia japonica from the far east is presented . two subspecies are now known : d . j . japonica ( n = 8 , 2x = 16 , 3x = 24 ) and d . j . ryukyuensis ( n = 7 , 2x = 14 , 3x = 21 ) . an attempt has also been made to determine the definition of the b - chromosome as lb and sb and the variation of the karyotypes of both subspecies is described . every known karyotype of d . japonica is classified into six groups ( see table 2 ) . d . japonica from many localities has a diploid karyotype ( 2x ) , a triploid karyotype ( 3x ) and an orthoploidic mixoploid karyotype of 2x & 3x . the origin and the karyological significance of these karyotypes are discussed .
a unique aspect of planarians is that they can regenerate a brain from somatic pluripotent stem cells called neoblasts , which have the ability to produce themselves ( self - renew ) and to give rise to all missing cell types during regeneration . recent molecular studies have revealed that the planarian brain is composed of many distinct neuronal populations , which are evolutionarily and functionally conserved ones , and acts as an information - processing center to elicit distinct behavioral traits depending on a variety of signals arising from the external environment . how can planarians regenerate such a brain ? on the basis of our recent findings , here we review the cellular and molecular mechanisms that regulate the stem cell dynamics involved in the brain regeneration of the planarian dugesia japonica . our findings suggest the possible value of in vivo planarian studies for guiding regenerative medicine to treat neurodegenerative diseases via interlinking stem cell biology and regeneration biology .
dugesia sicula is the only species of its genus not presenting an endemic or restricted distribution within the mediterranean area . it mostly comprises fissiparous populations ( asexual reproduction by body division and regeneration ) , most likely sexually sterile , and characterized by an extremely low genetic diversity interpreted as the consequence of a recent anthropic expansion . however , its fissiparous reproduction can result in an apparent lack of diversity within the species , since genetic variation within individuals can be as large as between them because most individuals within a population are clones . we have estimated haplotype and nucleotide diversity of cytochrome oxidase i within and among individuals along the species distribution of a broad sample of d . sicula , including asexual and the two only sexual populations known today ; and predicted its potential distribution based on climatic variables . our aim was to determine the centre of colonisation origin , whether the populations are recent , and whether the species is expanding .
asexual worms of fissiparous strain of the planarian dugesia ryukyuensis switch from asexual to sexual reproduction , if they are fed with sexually mature worms of bdellocephala brunnea . this suggests that the sexually mature worms have a sexualizing substance ( s ) that induces the sexuality in the asexual worms . here , we found by analysis of the sexualization that the cessation of the fission , namely their asexual reproduction , occurs immediately after the acquisition of sexuality . this result suggests that the downstream mechanisms induced by the putative sexualizing substance in b . brunnea become responsible for the cessation of fission . we also found that the decapitation triggers fission in the worms even after the acquisition of sexuality if they are not sexually mature , while the fully sexualized worms never fission even though they are decapitated . this result suggests that the cessation of fission takes place via at least two steps : ( 1 ) the mechanisms associated with the cephalic system ; ( 2 ) other mechanisms independent of cephalic control .
to investigate the relationship between phylogeny and glycan structures , we analyzed the structure of planarian n - glycans . the planarian dugesia japonica , a member of the flatworm family , is a lower metazoan . n - glycans were prepared from whole worms by hydrazinolysis , followed by tagging with the fluorophore 2 - aminopyridine at their reducing end . the labeled n - glycans were purified , and separated by three hplc steps . by comparison with standard pyridylaminated n - glycans , it was shown that the n - glycans of planarian include high mannose - type and pauci - mannose - type glycans . however , many of the major n - glycans from planarians have novel structures , as their elution positions did not match those of the standard glycans . the results of mass spectrometry and sugar component analyses indicated that these glycans include methyl mannoses , and that the most probable linkage was 3 - o - methylation . furthermore , the methyl residues on the most abundant glycan may be attached to the non - reducing - end mannose , as the glycans were resistant to α - mannosidase digestion . these results indicate that methylated high - mannose - type glycans are the most abundant structure in planarians .
an assay system has been established for the sexual induction in the oh strain , an exclusively fissiparous ( asexual ) strain , of dugesia ryukyuensis by feeding them with sexually matured worms of bdellocephala brunnea , an exclusively oviparous ( sexual ) species . in this assay system , asexual worms gradually differentiated sexual organs , namely the ovary , testis , genital pore and yolk gland in this order , and eventually mated and laid cocoons filled with fertilized eggs . although the oh strain worms were believed not to have any sexual organs , a pair of undeveloped ovaries with a few oogonia were detected by an intensive histological search . along with the progression of sexualization , five distinct stages were histologically recognized : in the first stage , the ovaries became larger enough to be externally apparent ; oocytes appeared first at stage 2 ; the primordial testes emerged at stage 3 ; a genital pore opened , yolk gland primordia developed and spermatocytes appeared at stage 4 ; and finally at stage 5 matured spermatozoa and yolk glands were formed . worms in stages 1 and 2 but not in later stages returned asexual if feeding on b . brunnea was interrupted . furthermore , when the worms at stage 3 onwards were cut posterior to the ovaries , all the tail regenerants developed eventually into fully sexualized worms . taking these results in account , we have concluded that the process of sexualization has a point - of - no - return between stages 2 and 3 . it is likely also that the testes , even the primordia , play an important role in the maintenance and development of sexuality .
n2 - an assay system has been established for the sexual induction in the oh strain , an exclusively fissiparous ( asexual ) strain , of dugesia ryukyuensis by feeding them with sexually matured worms of bdellocephala brunnea , an exclusively oviparous ( sexual ) species . in this assay system , asexual worms gradually differentiated sexual organs , namely the ovary , testis , genital pore and yolk gland in this order , and eventually mated and laid cocoons filled with fertilized eggs . although the oh strain worms were believed not to have any sexual organs , a pair of undeveloped ovaries with a few oogonia were detected by an intensive histological search . along with the progression of sexualization , five distinct stages were histologically recognized : in the first stage , the ovaries became larger enough to be externally apparent ; oocytes appeared first at stage 2 ; the primordial testes emerged at stage 3 ; a genital pore opened , yolk gland primordia developed and spermatocytes appeared at stage 4 ; and finally at stage 5 matured spermatozoa and yolk glands were formed . worms in stages 1 and 2 but not in later stages returned asexual if feeding on b . brunnea was interrupted . furthermore , when the worms at stage 3 onwards were cut posterior to the ovaries , all the tail regenerants developed eventually into fully sexualized worms . taking these results in account , we have concluded that the process of sexualization has a point - of - no - return between stages 2 and 3 . it is likely also that the testes , even the primordia , play an important role in the maintenance and development of sexuality .
ab - an assay system has been established for the sexual induction in the oh strain , an exclusively fissiparous ( asexual ) strain , of dugesia ryukyuensis by feeding them with sexually matured worms of bdellocephala brunnea , an exclusively oviparous ( sexual ) species . in this assay system , asexual worms gradually differentiated sexual organs , namely the ovary , testis , genital pore and yolk gland in this order , and eventually mated and laid cocoons filled with fertilized eggs . although the oh strain worms were believed not to have any sexual organs , a pair of undeveloped ovaries with a few oogonia were detected by an intensive histological search . along with the progression of sexualization , five distinct stages were histologically recognized : in the first stage , the ovaries became larger enough to be externally apparent ; oocytes appeared first at stage 2 ; the primordial testes emerged at stage 3 ; a genital pore opened , yolk gland primordia developed and spermatocytes appeared at stage 4 ; and finally at stage 5 matured spermatozoa and yolk glands were formed . worms in stages 1 and 2 but not in later stages returned asexual if feeding on b . brunnea was interrupted . furthermore , when the worms at stage 3 onwards were cut posterior to the ovaries , all the tail regenerants developed eventually into fully sexualized worms . taking these results in account , we have concluded that the process of sexualization has a point - of - no - return between stages 2 and 3 . it is likely also that the testes , even the primordia , play an important role in the maintenance and development of sexuality .
abstract =
an assay system has been established for the sexual induction in the oh strain , an exclusively fissiparous ( asexual ) strain , of dugesia ryukyuensis by feeding them with sexually matured worms of bdellocephala brunnea , an exclusively oviparous ( sexual ) species . in this assay system , asexual worms gradually differentiated sexual organs , namely the ovary , testis , genital pore and yolk gland in this order , and eventually mated and laid cocoons filled with fertilized eggs . although the oh strain worms were believed not to have any sexual organs , a pair of undeveloped ovaries with a few oogonia were detected by an intensive histological search . along with the progression of sexualization , five distinct stages were histologically recognized : in the first stage , the ovaries became larger enough to be externally apparent ; oocytes appeared first at stage 2 ; the primordial testes emerged at stage 3 ; a genital pore opened , yolk gland primordia developed and spermatocytes appeared at stage 4 ; and finally at stage 5 matured spermatozoa and yolk glands were formed . worms in stages 1 and 2 but not in later stages returned asexual if feeding on b . brunnea was interrupted . furthermore , when the worms at stage 3 onwards were cut posterior to the ovaries , all the tail regenerants developed eventually into fully sexualized worms . taking these results in account , we have concluded that the process of sexualization has a point - of - no - return between stages 2 and 3 . it is likely also that the testes , even the primordia , play an important role in the maintenance and development of sexuality .
,
copyright © 1999 - 2018 john wiley & sons , inc . all rights reserved
enter your email address below . if your address has been previously registered , you will receive an email with instructions on how to reset your password . if you don ' t receive an email , you should register as a new user
confused by a class within a class or an order within an order ? please see our brief essay .
to cite this page : myers , p . , r . espinosa , c . s . parr , t . jones , g . s . hammond , and t . a . dewey . 2018 . the animal diversity web ( online ) . accessed at https : / / animaldiversity . org .
disclaimer : the animal diversity web is an educational resource written largely by and for college students . adw doesn ' t cover all species in the world , nor does it include all the latest scientific information about organisms we describe . though we edit our accounts for accuracy , we cannot guarantee all information in those accounts . while adw staff and contributors provide references to books and websites that we believe are reputable , we cannot necessarily endorse the contents of references beyond our control .
this material is based upon work supported by the national science foundation grants drl 0089283 , drl 0628151 , due 0633095 , drl 0918590 , and due 1122742 . additional support has come from the marisla foundation , um college of literature , science , and the arts , museum of zoology , and information and technology services .
is a triclad turbellarian found across north america . human activities have extended the range of
to parts of northwestern europe and eastern asia , with notable population densities in great britain and japan .
( cash , et al . , 1993 ; gee , et al . , 1998 ; pickavance , 1971 ; sluys , et al . , 2010 )
is typically present in lakes , ponds , and streams in temperate regions . it shows negative phototaxis and dwells in the benthic zones of freshwater biomes as a result . the microhabitats for this organism include the undersides of rocks , plant material , and other types of debris found on lake and stream beds . the existing literature does not specify a depth range for the organism , but studies indicate the presence of
( folsom and clifford , 1978 ; gee , et al . , 1998 ; stokely , et al . , 1965 ; takano , et al . , 2007 )
is colloquially known as a flatworm , and it has a body that is flattened dorsoventrally . additionally , the body plan exhibits cephalization , and the body surface is covered with cilia used to facilitate gliding locomotion . sensory lobes known as auricles make the head region look triangular , and eyespots called ocelli are found on the head . in terms of coloration , the body is typically brown with white and yellow spots . the average length of
is 9 to 15 mm , but body dimensions can vary due to the organism ' s ability to regenerate lost parts .
( pickavance , 1971 ; salo and baguna , 1984 ; sluys , et al . , 2010 ; smales and blankespoor , 1978 )
that are produced sexually hatch from a cocoon , and are typically 2 . 0 to 4 . 5 mm in length when first hatched . they are transparent , and have visible yellow yolk cells . as they grow , they use up the yolk , and the spots of pigment grow and darken . individuals are considered mature after reaching a mean length of 9 mm .
is hermaphroditic , and only some populations reproduce sexually . there is no courtship process , and when one individual encounters another , it glides on top of it . they either both face the same direction or opposite directions , and the top flatworm moves its head back and forth over either the head or dorsal side of the bottom flatworm , stimulating it . after several minutes , both lift their tail ends , maneuvering so that both ventral sides meet , and the penes are mutually inserted . copulation can last 1 minute to 1 . 5 hours , and ends when the pair separates and leaves . individuals can mate many times in their lives .
reproduces both sexually and asexually . some populations reproduce solely sexually , while others reproduce only by fission , and still other populations reproduce both ways . high temperatures ( at approximately 26°c ) permit asexual transverse fission , whereas lower temperatures ( approximately 20°c ) yield a preference for sexual reproduction . some populations therefore switch from asexual fission to mating seasonally . reproduction for
reaches its peak during the summer months . an adult delivers a cocoon that attaches to surfaces by means of a short stalk . the cocoons have mean diameter of 1 . 30 mm and give rise to a mean of about 4 newborns upon hatching . an individual can produce multiple cocoons during its lifetime .
( folsom and clifford , 1978 ; vowinckel and marsden , 1971 ; vreys , et al . , 2002 )
produces a cocoon for every group of offspring produced , and provides provisioning . otherwise , there is no parental care .
do not show any signs of degenerative aging due to their regenerative capabilities . it is reported that the mortality rates of fed individuals are negligible because they are solely due to experimental accidents . it is also presented in the literature that
is able to reabsorb its body tissues and shrink in size to prevent death from famine .
is free - swimming and exhibits gliding locomotion with the help of mucus secretions as well as cilia that cover the body surface . individuals can be found both independently or in groups . group foraging has been observed to increase rates of daily per capita ingestion , which drives increased rates of asexual fission .
( cash , et al . , 1993 ; pickavance , 1971 ; smales and blankespoor , 1978 )
is considered one of the most primitive animal forms known to possess a central nervous system for higher order perception and integration . these flatworms are equipped with two eyespots called ocelli that appear as dark pigment cups on the anterior dorsal surface .
also has two earlike lobes as part of its anterior head region that function in tactile and chemical sensation . these structures , called auricles , have receptors and cilia on them to facilitate such sensation and perception . gliding mobility is facilitated by cilia covering the body surface , and the organism shows negative phototaxis upon exposure to light .
( smales and blankespoor , 1978 ; takano , et al . , 2007 )
uses its mucus secretions not only for gliding locomotion but also for capturing prey items . it has been observed that
exhibits a threshold temperature for feeding . feeding is significantly reduced or completely stops below a critical temperature of 6°c .
functions to inhibit being captured by these organisms . group foraging is reported to increase survival rates .
( cash , et al . , 1993 ; davies and reynoldson , 1969 )
serves as prey to a variety of animals , including fish , amphibians , and insects . it is also a predator itself of insects , aquatic worms , and crustaceans . as a significant predator of insect larvae , particularly mosquitoes ,
has been introduced to catch basins in ontario to successfully limit the population growth of immature mosquitoes . however , mosquito populations were not observed to be effectively controlled after introducing these flatworms to vernal pools in north dakota .
( cash , et al . , 1993 ; davies and reynoldson , 1969 ; meyer and learned , 1981 )
is equipped with a central nervous system ( cns ) for integrative neuronal communication and has regenerative abilities . consequently , this flatworm has been increasingly used as a model organism for educational and research purposes to better understand both tissue regeneration as a result of wear and tear and brain development as the main neural processing center in animals . genetic research at the molecular level is currently underway for these organisms to attempt to shed light on human growth , development , and tissue turnover . additionally ,
has been introduced to some bodies of water in an attempt to control mosquito populations through larval predation by these flatworms , to varying degrees of success .
( meyer and learned , 1981 ; salo and baguna , 1984 ; takano , et al . , 2007 )
it is suggested that feeding populations of this species do not age and are therefore considered immortal due to their regenerative capabilities .
in terms of its growth and regenerative patterns are regulated by a temporal pattern . the rate of mitosis is observed to have an initial maximum 4 to 12 hours after injury , fall to a minimum at 1 day , and then rebound to attain a second maximum after 2 to 3 days . anterior and posterior regenerative patterns show the most rapid rate of mitotic activity residing near the site of a wound and diminishing at body sections away from an injured body section .
rosario saccomanno ( author ) , the college of new jersey , keith pecor ( editor ) , the college of new jersey , angela miner ( editor ) , animal diversity web staff .
living in the nearctic biogeographic province , the northern part of the new world . this includes greenland , the canadian arctic islands , and all of the north american as far south as the highlands of central mexico .