pezosiren portelli is a basal sirenian from the early eocene of jamaica , 50 million years ago .

the type specimen is represented by a jamaican fossil skeleton , described in 2001 by daryl domning , a marine mammal paleontologist at howard university in washington , dc .

it is believed to have a hippopotamus-like amphibious lifestyle , and is a perfect example of a transitional form between land and sea mammals .

p. portelli had the typical skull and basic body shape shared by most modern sirenians , such as manatees and dugongs , but also had four limbs , not yet modified into flippers , with well-developed feet that were still adapted for walking on land .

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with its heavy body structure , pezosiren portelli most likely spent most of its time in water .
a restoration of pezosiren the bones in grey represent parts of the skeleton that were recovered . from domning ( 2001 ) .
this is a very important transition fossil between pezosiren portelli and potamosiren magdalenensis . we found it in jamaica in 2013 and it is named after us .
pezosiren portelli , named after its discoverer roger portell , was first found in jamaica in 1990 . it filled the gap between sirenians and their ancestors that lived on land .
pezosiren portelli is an important fossil because it represents the earliest known member of sirenia that was still a quadruped ( walked on four legs ) . pezosiren portelli was fully capable of walking on land , despite seemingly spending the majority of its time in the water . this is a key feature because modern sirenians ( dugongs and manatees ) have no back legs whatsoever and have completely lost the capability of emerging on land . thus , pezosiren portelli can be seen as a very early transitional species in the sirenia line ( domning , 2001 ) .
in order to acquire more abundant food resources , pezosiren portelli developed body structrures that would enable it to live in the sea . its main food would be sea grass and algae .
it still lives in the jamaican and african waterways but does not come to land as often as the pezosiren portelli . it thrived in warm shallow water with an overall tropic environment .
first pezosiren portelli fossil was found from middle eocene rocks in jamaica . the eocene period was a period of global warming , with temperatures across the planet soaring . forests thrived and trees grew even in polar regions . jamaica in the eocene period was a coastal area on the equator . therefore , pezosiren portelli lived in tropical climate , spent most of its time in the sea but walked on land too .
pezosiren portelli is a species of extinct sirenia ( the group of animals that includes modern dugongs and manatees ) . it was named by domning in 2001 after fossils were found in seven rivers , jamaica . pezosiren portelli appeared in the early eocene ( about 53 - 49 million years ago ) and was roughly the size of the modern feral pig ( prista , estevens , agostinho , & cachão , 2013 ) .
pezosiren is the first known quadrupedal sirenian , and represents a transitional form between terrestrial and marine sirenians . pezosiren had four limbs perfectly adapted to walking instead of flippers but at the same time the typical skull , teeth and thickened ribs of the fully aquatic , â€˜normalâ€™ sirenians . its pachyosteotic ribs , providing ballast , indicate that it was semi - aquatic , perhaps filling a niche similar to that of the modern hippopotamus .
sea cows once walked on land . pezosiren leaves no doubt of that . this roughly 48 million year old mammal once trod over prehistoric jamaica , and looked akin to a hippo with the skull of a manatee . much like pakicetus in the history of early whales , pezosiren embodies a critical transitional period in the evolution of manatees and dugongs , yet the place where this amphibious sea cow was found did not match what paleontologists expected .
pezosiren was in every other respect , a modern manatee , except that it still had a definite , ( albeit reduced ) pelvis and four still fully - functional legs . the tail was missing and may have been heavier than indicated here as they evidently used them early on . otherwise , pezosiren must have occupied a similar niche to what hippos do now , spending almost all of its time walking the bottom of shallow waterways - which manatees today still do .
if you only saw the skull of pezosiren you might be fooled into thinking it was a fully aquatic form like modern sirenians . while it’s skull differs in some subtle ways , it is easily identifiable at first glance as being a relative of manatees and dugongs . the strange thing is , however , that pezosiren had four limbs and almost certainly was an amphibious creature . it could still walk on land and did not have the swimming adaptations seen in its later relatives .
the site is particularly noteworthy for the mammal fossils that it yields , which include the rhinoceros , hyrachyrus , and a new genus and species of fossil sea cow pezosiren portelli domning , the latter named in the 11th october edition of nature by daryl domning . this is the most complete , primitive sea cow yet discovered , and is unique to jamaica . pezosiren is a distant relation of the endangered manatee that has flippers , and lives in the shallow seas around jamaica .
could pezosiren , an eocene relative of modern manatees from the rock of jamaica and described by d . p . domnig in 2001 , have moved in a similar fashion ? today manatees and their relatives within the sirenia are adapted to a fully aquatic lifestyle ; their forefeet are stubby flippers , they lack hindlimbs , and they propel themselves with up - and - down oscillations of their broad tails . like whales , however , sirenians evolved from terrestrial ancestors , and pezosiren is a startling creature that helps illustrate how sirenians became adapted to aquatic life .
the bone is about 50 million years old . the researchers guess the animal it once belonged to resembled pezosiren more than the modern sea cow , though the bone also hints that the chambi manatee spent a lot of time in the water since the inner ear resembles that of whales .
for more on pezosiren portelli , see domning ( 2001 ) ; the diagram contrasting the prorastomid , protosirenid and crown - sirenian is from domning ( 2000 ) . the steller’s sea cow painting is by maurice wilson . sirenians were previous covered on tet zoo in when manatees crossed the atlantic .
pezosiren was a pig - sized animal with a length of 2 . 1 m . it had a short neck , a barrel - shaped trunk , a moderate - lengthed tail and four short legs . the skeleton will eventually be displayed in the geology museum at the university of the west indies * .
thanks for comments , brian . i would be happy to discuss pezosiren at length ( and desmostylians ) , given appropriate time and perhaps access to new images and data 🙂 as for enamel microstructure… histology of any kind doesn’t exactly push my buttons , but i know how important it can be as goes biology and evolution .
at left is an artists ' conception of moeritherium , one of the most basal members known of the order , proboscidea which includes elephants . on the right is an artist ' s conception of pezosiren , one of the most basal members yet known of order sirenia , the family of dugongs ,
sea cows
, and manatees , even though no modern manatee has legs anymore . .
i’m intrigued by the diagram next to the pezosiren dot - point , suggesting that the relative positions of the center of mass and center of bouyancy have changed over the course of sirenian evolution . this is plausible enough , but are the remains of pezosiren and other eocene sirenians complete enough to allow calculation of their centers ? — i’ve also had a niggle for years about moeritherium . the most recent cladograms i’be seen put it closer to extant proboscidea than to sirenia or desmostylia , but its apparently aquatic life - style makes it seem like a good analogue , at least , for the ancestors of the sirenia . ( and the description of the likely life posture of desmostylia in post # 20 sounds like what embrithopoda might have evolved toward if they’d had a chance ! ) prediction : new discoveries will lead to major revision in our picture of the early evolution of the thethytheria !
since the chambi sea cow is only represented by a single skull piece , benoit and colleagues can’t say exactly what this animal looked like . based on the mammal’s early age and relationships , it was probably a legged sirenian that looked more like pezosiren than a modern manatee . and even though the sirenian probably had legs able to support the animal on land , the petrosal bone contains clues that the chambi sea cow was a proficient swimmer .
the only other closely related fossil sea cow is prorastomus sirenoides owen , which is known from a skull and atlas vertebra found loose in quashies river , trelawny , and attributed to the stettin formation of early eocene age . the details of the legs in this form are , however , unknown . the morphology of the skeleton of pezosiren is comparable to that of similar - sized land mammals and indicates that pezosiren was capable of supporting its body weight out of water . other characteristics ( such as , details of the nasal opening and the thick ribs ) , however , suggest that it spent much of its time in the water . this new species of sea cow represents a unique glimpse of a stage in their evolution when they made the transition from the land to the sea . * donations to the sea cow fund can be sent to dr . sherene james - williamson curator , department of geography and geology , university of the west indies , mona , kingston , jamaica .
going back to the post’s title – i was hoping to see more discussion about pezosiren… i’m working with daryl domning right now on that critter’s enamel microstructure , and noticed that virtually nowhere on scienceblogs is there any mention of enamel microstructure ( aside from one post by afarensis on humans , with no images of it there ) . i wonder , why not ? there is some really cool work on what amounts to the evolution of histology , and i bet lots of people would really get into it .
re # 37 and # 38– enamel microstructure is one of the key pieces of evidence about mesozoic mammals ( hey , if all you’ve got is “the tooth , the sometimes broken and incomplete tooth , and nothing but the tooth” you look at it as closely as you can ! ) . the down side ( my impression from reading ) being that there are a limited number of possible microstructures , with the derived ones having evolved repeatedly all over the family tree ! but i’ll be interested to see what it tells us about pezosiren .
in the evolutionary history of aquatic mammals , sea cows , the group that includes manatees and dugongs , once walked into the sea . it was all the rage during the early tertiary as intermediate forms of mammals adapted to a marine life . but something was missing in the history of sea cows . none of the fossil evidence till now has shown a sea cow ancestor with four legs strong enough to support its weight on land . when did they make that critical transition from land to sea and what did the animal look like ? [ daryl domning with the 50 million - year - old sea cow skeleton of pezosiren portelli . photo by christina reed . ]
sea cows , also known as manatees , were not always the florida - dwelling gentle giants of the sea that they are today . in fact , they once walked on land . their 48 - million - year - old ancestor , pezosiren , ran all over prehistoric jamaica and resembled a hippo at first glance . but sea cows also share ancestry with elephants , which first appeared in africa around 66 million years ago . paleontologists , however , have always drawn a blank on the evolutionary link between the manatee ’s african and jamaican relatives—until now . researchers digging around in tunisia found a skill fragment that fills the missing piece of the puzzle . national geographic continues :
sirenian skulls even today are very similar to proboscidian skulls , especially basal forms like moeritherium . in addition , with sirenians we have a complete sequence of transitional forms from prorastomus , ( a pre - sirenian form ) to walking manatees like pezosiren to subsequent forms which still had all four legs , but weren ' t able to support their bodies out of water anymore . they had become obligate swimmers . we then we have others in which the rear limbs are so small as to be impossible to do anything with anymore . and these lead to a form where the pelvis is gone altogether , and the rear legs have dwindled to no more than a single bone .
indeed , pezosiren looked very hippo - like . it was short and barrel - bodied , and it also had osteoslerotic bones . this was not an animal that was just dipping its toes into the water but one that was already semi - aquatic . there is little doubt that it was spending considerable time in an aquatic environment . i do not know of any studies seeking to reconstruct the locomotion of this animal , but it would seem a fair inference to suggest that while its movements would be restricted on land it would have exhibited a wider range of movements under the water . it may have moved in ways analogous to , but not exactly like , the hippos studied by coughlin and fish .
in the big picture of mammalian evolution , sea cows are paenungulates – members of a group that also encompasses hyraxes , elephants , and extinct branches such as the double - horned arsinoitherium and the aquatic desmostylians . the earliest members of these lineages first appear in africa shortly after the end - cretaceous extinction of 66 million years ago , with the perplexing exception of the sea cows . the earliest , most archaic progenitors of today’s manatees and dugongs , such as pezosiren , have been found in jamaica . anatomical and genetic evidence is clear that sea cows must have shared an african origin with the other paenungulates , but , until now , no one has picked up the fossil trail of the earliest sirenians .
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( eds mazin , j . - m . & de buffrénil , v . ) 151–168 ( dr friedrich pfeil , munich , 2001 ) .
, new species ( mammalia , sirenia ) , from the late middle eocene of wadi hitan , egypt .
the role of phenacodontids in the origin of the modern orders of ungulate mammals .
fossil sirenia of the west atlantic and caribbean region . v . the most primitive known sirenian ,
functional significance of bone ballast in the evolution of buoyancy control strategies by aquatic tetrapods .
i thank j . bailey , b . beatty , d . da silva , h . dixon , s . k . donovan , r . j . emry , c . flemming , f . grady , h . and j . halvorson , j . herrera , k . hickey - commins , s . hutchens , s . jabo , d . jones , i . a . koretsky , j . kramer , b . j . macfadden , c . macgillivray , r . d . e . macphee , s . mitchell , r . w . portell , t . radenbaugh , k . s . schindler , t . a . stemann , c . terranova , and b . , r . and j . toomey . field work was funded by the national geographic society ; b . and r . toomey ; the potomac museum group ; the university of the west indies ; the american museum of natural history ; and r . liberman .
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full reference : d . p . domning . 2001 . the earliest known fully quadrupedal sirenian . nature 413 : 625 - 627
like the hippo today , the fossilized animal could live on land or in water .
we think this animal spent much more of its time in the water .
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have you ever tried to walk along the bottom of a pool while fully submerged ? it isn’t easy . keeping your feet on the bottom is enough of a task , and you would probably need a weight belt to take an underwater stroll . hippos ( hippopotamus amphibius ) , though , walk and even prance along the bottom of lakes and rivers with ease . how do they do it ?
when compared to a whale or even a manatee ( the latter of which i will address a bit later on ) a hippo does not look especially well - adapted to life in the water . it has a low , squat body and lacks a broad tail , flippers , or any other broad surface to help propel itself through the water . neither is this amphibious mammal well - suited to quick movements on land . hippos can trot a bit , but they are so cumbersome that while walking on dry land they always keep three of their feet in contact with the ground at a time .
the hippo is obviously a cumbersome animal , but it is not just because of their tubby physique . parts of the appendicular skeleton of hippos are osteosclerotic , meaning that their bones are extraordinarily dense due to the replacement of porous bone with more compact bone . ( hippos have extra , lighter bone material in the large medullary cavities within their limb bones , too . ) this means that their bones act as a kind of ballast to help them achieve neutral buoyancy underwater . without this added weight they would have to actively expend a lot of energy to remain underwater ( and , conversely , too much “bone ballast” would make it harder to surface when they needed to come up for air ) .
this adaptation to aquatic life allows hippos to exhibit a greater range of locomotion under the water than on land . since they do not have to actively hold themselves down , and the watery environment buoys them up , they can walk , prance , and even “fly” underwater . this range of movement was recently described by biologists brittany coughlin and frank fish in the journal of mammalogy after observing the two female hippos kept at adventure aquarium in camden , new jersey . *
* [ as a side note , these individual hippos often harass and even attempt to eat the birds kept within the enclosure . many captive birds have died from stress as a result . this raises questions about the ethics of attempting to create a “natural” setting for aggressive animals in zoos and aquariums . ]
a hippo moving underwater . note how it uses minimal movement of its forelimbs to push off from the bottom .
unfortunately the size of the hippo enclosure and the amount of time selected for study limited the observational data , but coughlin and fish still recorded 102 sequences of hippos moving underwater ( of which 32 were selected for analysis ) . the hippos did not perform their full locomotive repertoire , but they did often walk by the viewing window along the pool bottom . when they did so they moved in a sort of slow - motion gallop with only one foot ( vs . three on land ) in contact with the ground at any one time . it almost goes without saying that the hippos would not be able to move the same way on land as they did underwater .
coughlin , b . , & fish , f . ( 2009 ) . hippopotamus underwater locomotion : reduced - gravity movements for a massive mammal journal of mammalogy , 90 ( 3 ) , 675 - 679 doi : 10 . 1644 / 08 - mamm - a - 279r . 1 domning , d . ( 2001 ) . the earliest known fully quadrupedal sirenian nature , 413 ( 6856 ) , 625 - 627 doi : 10 . 1038 / 35098072
type specimen : usnm 511925 , a mandible . its type locality is seven rivers [ guys hill mbr , chapelton fm ] , which is in a lutetian estuary / bay sandstone / siltstone in the chapelton formation of jamaica .
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moeritherium looks so much like a tapir because they ' re closely - related members of order , perissodactyla , animals with odd - numbered hooves . the tapir side of the family ( embrithopoda ) inherited three - toed feet ( on the hind legs ) , and led to things like the rhinoceras and the titanic indricathere . the five - toed side of the family ( tethytheria ) split into two major groups , proboscidea ( the elephant family ) and desmostylia , which include sea cows .
it turns out there is more than just superficial similarity here . jugding by comparing both their skulls and their genes , elephants and manatees have a surprisingly close ancestral relationship .
this is the most primitive fossil found so far . we ' ve found others with legs that couldn ' t support the animal ' s body weight . but this is the first whole skeleton with legs that could support the animal ' s body weight out of water , yet has clear adaptations for aquatic life . we essentially have every stage now , from a terrestrial animal to one that is fully aquatic .
together with fossils of later sirenians elsewhere in the world , these new specimens document one of the most marked examples of morphological evolution in the vertebrate fossil record . ”
reduced sacroiliac articulation , but could probably still support its body weight out of the water .
proboscidian tails dwindled into little more than fly swatters , but sirenian tails developed broad and and flat like beaver ' s tails . this is how manatees ' tails still are today . dugongs ( sea cows ) are another member of that family , and they are more derived [ evolved ] in that their tails have flukes , a much more efficient crescent shape like whales or sharks have .
with the exception of sea cows , sirenians are exclusively tropical . their fossils are usually found in what used to be the tethys sea , an ancient ocean that once divided the supercontinents of laurasia and gondwana . both of these further divided eventually forming the continental masses we have today . but the tethys sea is now dry land .
evolution usually leads to a branching out of several distinct forms , rather than changing just one . that ' s how evolution theory explains biodiversity and the evident ancestry implied by taxonomy . sirenians diverged into several different families , some of which are now completely extinct , and known only from fossils . sadly , some of these species remain unnamed , and there are no available illustrations of them to show .
hooves are essentially just really thick fingernails that cover the whole tip of the finger . whales and sirenians both evolved from separate sets of hooved land mammals , but not from the same families . whales are descended from carnivorous artiodactyls , but sirenians are descended from herbivorous tapir - like things . the idea that anything could go from hooves to fins may be a difficult one to accept . but compelling evidence of this is the fact that sirenians still have hooves . and there is no other explanation for why anything with flippers should still have finger bones , much less fingernails , and especially not hooves !
ribs are round and thick unlike the light and thin ones of other land animals , which served as ballast .
it eats seagrass and algae and comes to land only to escape water predators . it uses its flippers and small hind legs to push itself onto land . its tail moved up and down , like modern water mammals today .
it was found in parts of modern day columbia . it is part of the family trichechidae , which is often considered an unusual form of a modern walrus
it lived during the late eocene epoch to early oligocene epoch . during this time , the water was still warm and the climate was still tropic .
it stayed in the warm shallow waters and ate seagrass . it was also more well equipped for life in water due to its longer tail .
the sirenian ( sea cow ) is split up into two family groups : trichechidae and dugongidae . its fossil record starts from the early eocene epoch to present day . the sirenian had the most diversity during the miocene epoch . this was due to the deep nutrient - rich waters during this period . the decline of diversity was caused by climate change , availability of aquatic vegetation , and competition with other marine mammals . their closest living relative today is proboscidea , or elephants .
i don’t have time for anything at the moment , it’s terrible . so here’s this , from one of my talks on marine mammal diversity and evolution…
domning , d . p . 2000 . the readaptation of eocene sirenians to life in water . historical biology 14 , 115 - 119 .
– . 2001 . the earliest known fully quadrupedal sirenian . nature 413 , 625 - 627 .
interesting . i wonder what sort of transitional stage sirenians went through between their terrestrial afrotherian ancestors and the highly derived crown - sirenians we all know and love . was it some sort of semi - aquatic freshwater hippo - like herbivore , or could it have been more marine . alternatively , it may have been semi - aquatic and freshwater dwelling , but it may not have been hippo - like .
i suppose the only way to determine for sure is to go find some more paleocene sites in africa .
also , the body of hydrodamalis gigas and other hydrodamalines is proportionately large relative to the head when compared to other dugongids ( and trichechids ) , an adaptation to life in colder waters .
anyone at all interested in fossil sirenians should take time to look at jorge’s blog – it’s one of my favourites , i congratulate you 🙂 one quick question you might like to answer , jorge : are sirenians particularly abundant and / or diverse in the caribbean region compared to elsewhere ( they certainly seem to be ) ? if so , any idea why ? centre of endemism ? i suspect this has already been answered in the literature but , as we all know , i’m lazy .
it’s such a tragedy that steller’s sea cow was hunted down so quickly after its discovery . it would have been interesting to see how it fit into its ecosystem . i’m particularly curious about finding out how it interacted with the marine predators of the region such as killer whales or sharks . i find it hard to believe a slow and fairly harmless sirenian could properly fight off or outrun these predators to protect itself or its offsprings…
how many fossils are still around ? if it was hunted by whalers , maybe they dragged the carcasses up on land to butcher them , leaving the bones on terra firma where parts of the bones may remain today . i ask , because of the success of svante pääbo and his team at max planck institute to sequence the genomes of extinct species from old bones . of course , to get enough diversity for a * living * species you need at least 300 individuals ( more than the number of individuals likely to be preserved as specimen in museums ) , which is why i ask about the numbers…
wow , thanks ! yes , indeed , sirenians , particularly dugongids , seem to be more diverse in the western atlantic - caribbean ( wac ) region specially from the oligocene through the pliocene , domning ( 2001 ) elaborates on this . so far there are about 14 species described from that region during that interval of time ( plus at least 4 more that will be described in the next two years or so ) . during that same time interval , in the tethys / paratethys region , there are about 10 species , and from the indian region 4 are known . the seagrasses seem to have been more diverse in the wac region , so there were enough resources to sustain three ( maybe even four ) sympatric species and drive speciation . there’s lots of endemism , specially when talking about dugongines ( which seem to have originated there ) . it is very likely that still more species will be discovered in the future , specially in the greater antilles . even taxa that had been thought ( for many years ) to have originated in the tethys region are showing up in earlier deposits in the caribbean !
mattioli , s . & d . p . domning . 2006 . an annotated list of extant skeletal material of steller’s sea cow ( hydrodamalis gigas ( sirenia : dugongidae ) from the commander islands . aquatic mammals 32 ( 3 ) : 273 - 288 .
we just made a cast copy of a steller’s sea cow for a museum in scotland . such a strange animal . it’s a shame the nhm in vienna has their skeleton jammed way back in a corner .
i’ve always wondered about the natural history of the steller’s sea cow and happened to come across a nice overview of what is currently seen by some to be the state of these seacows back in those days , in a 2007 book “steller’s island” by dean littlepage , in which the author suggests that these creatures inhabited only a couple of suitable off - shore environments on a handfull of islands which presented relatively warm water refuges following the submergence of beringia as the current inter - glacial proceded . previously the beringian land - mass prevented warm pacific waters from entering the arctic ocean and caused those warmer pacific waters to pool along the shores of the north pacific and it was then that their range extended from the shahkalin islands to northern california . the author suggested that at the time that the first europeans began to exploit the species they were already in reduced numbers and confined to a very limited range . here’s a link to the amazon page . urltoken
i’m reading a novel , and i believe that the sirenians origins can be traced to the demostylians . but , when did steller’s sea cow appear in history ? does anybody know ? i think it’s a shame that it went extinct because , like the dodo , it is an odd animal and it’s ecological niche is somewhat of a mystery . i recommend “neptune’s ark” by david rains wallace for paleo - marine biology , it’s very informative .
birger johansson : there are still tons of sea cow bones on commander islands beaches . valagos : it apparently avoided predation by staying in shallow bays protected by rocky reefs . it is unclear how it managed to colonize the islands . doug : at the time of european discovery the commander islands were the only island group in the north pacific without present or past human inhabitants . i think it’s a much better explanation of the fact that the sea cow survived only there .
1 ) as far as recent bones of hydrodamalis go – i read somewhere that most of them sitting around on bering island had already all been picked up . sorry , i can’t provide a reference right now , but that’s the situation as far as i’m aware .
2 ) sirenians did not evolve from desmostylians , and the inverse is also not the case . sirenians can be traced back into the eocene , while desmostylians have a fossil record only back to the oligocene , and presumably evolved in southern or east asia , and ( last i remember ) potentially share some relationship with anthracobunids . sirenians and desmostylians do share common ancestry , however , and are both marine clades of the tethytheria .
3 ) damn , i wasn’t aware that there were 27 skeletons ; that’s quite a bit more than i remember . 62 skulls , damn .
i’m reading a novel , and i believe that the sirenians origins can be traced to the demostylians .
you can believe that , but that’s not what the evidence says . desmostylia appears in the fossil record at least about 15 million years later than sirenia . the divergence between the common ancestor of sirenia - proboscidea likely happened sometime in the late paleocene or earliest eocene , whereas that of desmostylia - proboscidea ( or anthracobunidae ) by the late eocene or early oligocene . so , like bobby says , one cannot be the direct ancestor of the other .
speaking of desmostylids…what was their m . o . ? i have a paper in my archives that suggests they were doggie - paddlers in the way of modern bears , and that they grubbed up marine flora with their tusks . but the paper is quite old . any news on these strangest of potentially semi - aquatic herbivores ?
boesse : in the late 1980 - s finding a bone took about half an hour of walking on the beach . i would be surprised if the situation has changed that much . if you are interested , i can ask a friend of mine who works there every summer .
re subfossil bones on bering island : there may be a lot more than the ones you can easily pick up . nordenskiöld who was there in 1879 and collected quite a lot of bones noted that the best way to find them was to probe 1 - 2 feet deep in the beach ridges . however he noted that ribs were scarcer than other bones because the locals used them as runners for sledges !
i ask , because of the success of svante pääbo and his team at max planck institute to sequence the genomes of extinct species from old bones .
steller’s sea cow mitochondrial dna was extracted already in the 1990ies ( ozawa et al . , 1997 ) from bones collected on bering island . ( i am not aware of any more recent molecular studies of this species , however . )
ozawa , t . , hayashi , s . & mikhelson , v . m . 1997 . phylogenetic position of mammoth and steller’s sea cow within tethytheria demonstrated by mitochondrial dna sequences . journal of molecular evolution 44 , 406 - 413 .
@ 5 birger : you may be able to buy the bones from steller sea cows . a company called dancing man knives in alaska is selling knives with handles reportedly made of that bone , and they have been for years ( urltoken ) . i don’t know where they’re getting it or if its real , but it can’t hurt to talk to them . their ulus are good tools , too .
as for sirenians and desmostylians , my take was that sirenians are to seals as desmostylians were to sea - lions . that might be overly simplistic , but my uneducated thought was that desmostylians seemed to be more agile , and perhaps adapted to high energy environments , such as the kelp beds of the pacific , estuaries , and similar environments that demand a modicum of athleticism to keep from being smashed by the waves . sirenians seemed adapted more for efficient cruising than at agility .
i like that last comparison ! it also seems reasonable to me . a few questions regarding desmostylians : – were desmostylians truly marine or were they more semi - aquatic and coasthugging creatures ? their absence beyond the northern pacific might be an indication there . - on the other hand , is it likely that they also occurred in the southern pacific or even the indian ocean ? - also , do we have any idea why demostylians went extinct ? - i recall demostylians being depicted with very short trunks ( or at least elongated noses ) . is this realistic ? – do we have any clues about the natural history of these creatures , beyond their habitat and diet ?
it appears that i was wrong then about the abundance of bones – good ! i’m glad i am , in this case . i wonder where i had heard that…
re : desmostylians – oxygen / carbon / strontium isotope data places desmostylians as feeding within somewhat fresh water ( or less saline water anyway ) . the delta o18 is marine , while the sr isotope signal appears terrestrial . so , whatever they were doing , they were doing it close to the shoreline . that being said , desmostylian fossils have only been found in marine deposits , and never in terrestrial deposits ( although it is important to recognize that many of the terrestrial deposits in california are pretty far inland – then again , so are some marine desmostylian - bearing deposits ) .
last i recall , desmostylians are thought to have fed upon algae or kelp ; otherwise , their posture during terrestrial locomotion is thought to have been pretty bizarre ( domning 2002 ) , with a digitigrade , chalicothere - like stance for its feet , a near vertially oriented pelvis and habitually dorsiflexed vertebral column . additionally , a paper by phil gingerich ( 2005 ) indicates that in terms of swimming style and skeletal proportions , desmostylus was most similar to the polar bear ( which is not surprising , looking at the skeleton of desmostylians ) . i don’t think there’s much evidence or need to invoke a trunk for desmostylians .
otherwise – they disappear sometime during the late miocene , and some of their youngest fossils ( in california , anyway ) are ~ 10 - 12 ma . this is roughly the same time that hydrodamaline sea cows start getting gigantic , and there is quite a bit of turnover in the ne pacific marine mammal fauna from the tortonian into the messinian . i can’t recall of the top of my head , but there have definitely been some hypotheses proposed – perhaps jorge can help me out here , or maybe brian beatty will see this .
i thought brian beatty had proposed that their extinction might relate to marine productivity moving farther offshore beyond the foraging range of desmostylians . alternatively , i am just imagining that .
i think it’s looking increasingly likely that the common ancestor for elephants and sirenians was aquatic . however , iirc , stable isotope analysis actually supports embrithopods being terrestrial ( or at least as terrestrial as modern elephants and such ) .
morgan churchill ( # 22 ) – thanks , didn’t know about the stable isotope stuff . i was going on the tradition of interpreting various skeletal features of arsinoitherium as suggesting aquatic tendencies .
i’m not sure if its entirely clear why the desmostylians went extinct . it does however correlate with the proliferation of hydrodamalines . were desmostylians outcompeted by hydrodamalines ? or did they went extinct because of increase in cold climate drove the seagrasses away from their range ? i really don’t know .
were the desmostylians eating sea - grasses ? sorry for the question , but i didn’t realize that one could tell the isotopic difference between sea grasses ( angiosperms ) green algae , and kelps .
i guess i was thinking about desmostylians eating kelp . being on the west coast of the us , one thing i do know is that kelps fluctuate enormously both within the year and between years . they’re fast growing , but they also get shredded by storms , as does sea grass .
in such a seasonal environment , i’d expect any grazer to have to both endure strong seasonality ( summer feast , winter famine ) and have to move as their food plants changed . manatees in the amazon have to deal with this type of environment now .
since desmostylians were big , i’d guess that simple environmental stochasticity drove them extinct . they may have simply gotten caught in a situation where they couldn’t find big enough patches of food plants to allow them to reproduce , or they may not have been as good at surviving bad seasons as the hydrodamalines . obviously i don’t know either , but i do know that the north pacific definitely does not live up to its name . it’s a very unstable place .
yes , desmostylians were eating seagrasses and yes , you can tell the difference between seagrasses and kelp . it is even possible to tell , in the case of sirenians , if they preferred large or small seagrasses , which i think its really cool !
clementz , m . t . , k . a . hoppe & p . l . koch . 2003 . a paleoecological paradox : the habitat and dietary preferences of the extinct tethythere desmostylus , inferred from stable isotope analysis . paleobiology 29 : 506 - 519 .
clementz , m . t . , s . sorbi & d . p . domning . 2009 . evidence of cenozoic environmental and ecological change from stable isotope analysis of sirenian remains from the tethys - mediterranean region . geology 37 : 307 - 301 .
right now , seagrasses are rare along the california coast , and their biomass appears to be strongly seasonal ( based on my frequent walks near a seagrass bed , and the amount that washes up over time . i’d still hypothesize that contraction of seagrass range may have doomed the desmostylians .
i guess the question is , what were the miocene hydrodamalines eating ? i know that manatees eat seagrass , but steller’s sea cow reportedly ate kelp . were the hydrodamalines simply more catholic in their dietary preferences ?
indeed , hydrodamalines seem to have been eating mainly kelp , hence the trend towards reducing the dentition ( to none in hydrodamalis spp . ) and rostral deflection .
previously the beringian land - mass prevented warm pacific waters from entering the arctic ocean and caused those warmer pacific waters to pool along the shores of the north pacific and it was then that their range extended from the shahkalin islands to northern california .
hard to believe that only the commander islands maintained warm enough water for this species to survive–warmer than northern california ? –especially when given the proven ease with which the sea cows were hunted to extinction . i can totally see the commanders as a last refuge for their population–from people , all too temporarily .
that is not a hard - and - fast rule , there are many examples of viable populations being established from fewer individuals . if you’re speculating about recreating a species from dna , trying to clone hundreds of separate individuals would probably not be the way to go . better to assemble the best possible consensus genome and fiddle with mhc genes and whatever is likely to affect viability ( but that assumes some greater hurdles can be cleared in this sf scenario , such as where to find a womb to incubate these things ! )
before we could attempt to use a dugong as a surrogate mother , we would first need to know how to successfully breed dugongs under captive conditions ; afaik , dugongs have never reproduced in captivity ( and only a handful of individuals have ever even been kept in zoos and aquaria ) .
manatees , on the other hand , have been bred in captivity – but they are of course far more distantly related to hydrodamalis than the dugong is .
@ vladimir dinets # 11 : interesting ! if they were confined to the commander islands because they had been hunted out everywhere else , then the present potential habitat of the sea cow might extend all the way to california . presumably it would be somewhat patchy . perhaps the sea cows would migrate seasonally between sheltered bays where they could escape the winter storm season and the more exposed coasts where the kelp forests grow . i wonder whether they could coast along on their fat reserves for a long period like migratory whales .
fjord country might be ideal for such a creature . imagine winter herds of sea cows like so many knobbly half - sunk logs in the quiet waters of the inner parts of puget sound .
i wonder how they avoided orcas off the commanders . or anywhere else for that matter .
in summary : here is an english translation of steller’s work on the sea cow . urltoken he based it on almost a year of continual observation of the animals in the wild .
i infer from his account that the population in the commander islands was in marginal habitat . the animals did most of their eating in north pacific kelp forests , but hung out mainly at river mouths . they were killed regularly by sea ice and by storms coming in off the bering and they were visibly emaciated at the end of the winter . imo , this implies that they would have done better ( bred more successfully , grown bigger , grown more quickly , lived longer ? ) someplace with estuaries and kelp that was more sheltered and also warmer , possibly with more plant species . this would put their largest areas of present potential north american habitat in a range from the inside passage to puget sound and south to the golden gate . their refugium during glacial intervals might be off baja california , or for all i know the coastline that is now underwater provided more habitat . distribution on the opposite coast of the pacific would be similar , with some island herds in marginal habitat between the two main ranges .
i’m sorry i missed all this discussion , especially the part about desmostylia . i think all the salient points were made , though i would urge that a distinction between algae eating and seagrass eating is important to make . as is the difference between what isotopes and other methods can discern about diets . animal diets are unfortunately very plastic and complex , as is the nature of the data we use to study it ( isotopes , microwear , morphology ) – we all need to be cautious about understanding the nature of the data we are using . that anyone can be certain about hypotheses about competition between hydrodamalines and desmostylians without really statistically knowing what they ate or how their temporal and spatial distributions overlapped should make us all uncomfortable . moreover , modern competition studies start with systems like that and then study how resource limitation , if it exists , may play a part . we haven’t established any notion about how algae or seagrasses were limited over the period of time of hydrodamaline / desmostylian spatial and temporal ranges , so how can we know it was competition ?


clea wykoffi is a species of freshwater snail with an operculum , an aquatic gastropod mollusk in the family buccinidae , the true whelks , most of which are marine .

clea wykoffi

- - - - - - - - - - - - - - - species : clea wykoffi r . a . m . brandt , 1974 - id : 5288000028
worms - world register of marine species - clea h . adams & a . adams , 1855
overally , clea species feed like their marine cousins . although clea helena is the most well - known in the genus , there are plenty of other species . here ' s a list from
while clea gemma ( conolly 1929 ) is the type for the afrocanidia ( sub ) genus from africa .
species clea fusca ( h . adams , 1862 ) accepted as anentome fusca ( h . adams , 1862 )
one more update ! i just found that canidia bocourti brot was synonymised as clea helena by brandt ( 1974 ) . best ! gianluca
clea helena is sometimes called clea ( anentome ) helena or anentome helena . it is a member of the whelk family buccinidae , and one of very few whelks that lives its entire life in freshwater habitats . common names in the trade include assassin snail and snail - eating snail .
clea are whelks , most of which live in the sea . like their marine relatives , clea are opportunistic carnivores that feed on both live prey and carrion . among the prey taken are snails , and it is this that has made them popular with fishkeepers . clea stay partially hidden under the sediment , and if a snail slides past , then quickly ( by snail standards ) jump into action , chasing their prey and eventually subduing it .
most clea live in clean , fast - flowing streams where they can be found in sandy or muddy substrates . clea helena is exceptional in being found in ponds and ditches too , and its tolerance for a wider range of water conditions is probably why this one particular species does so well in captivity .
clea helena is not difficult to breed , though it does so slowly , and isn’t likely to become a pest in the same was as many other snails . for one thing , being carnivorous , it is fussier about food , and that means an aquarium of given size will support a much smaller population of clea helena than omnivorous or herbivorous snails .
hello guys , i thought you may be interested in some updates : 1 ) afrocanidea gemma conolly , 1929 is an invalid taxon , synonym of gutturnium muricinum ( röding , 1798 ) it is a ranellidae ( note also the spelling of the invalid genus ) urltoken 2 ) the species list of congeners is not complete : c . broti ( deshayes 1876 ) c . cambojiensis ( reeve , 1861 ) c . funesta adams , 1861 c . fusca ( adams , 1861 ) c . scalarina ( deshayes , 1876 ) c . spinosa temcharoen , 1971 c . wykoffi brandt , 1974 some sites you may find useful : worldwide molluscan species database - bagni liggia urltoken urltoken
sungai jernih , perlis , northern peninsular malaysia . another typical habitat for many clea species as they have abundant prey to feed on and nutrient - rich waters flowing from nearby caves .
in the author’s experience , controlling a runaway malayan livebearing snail ( or malayan trumpet snail , melanoides tuberculata ) is to use 4 - 6 clea helena per 60 litres ( about 15 us gallons ) of water . while they won’t exterminate every last one of the malayan livebearing snails , the clea helena will keep the population of them small enough that they’re no longer troublesome .
usually , clea snails can be found in abundance when present in a water body . thus , when a prey is detected , a large number of snails will search and assemble around it .
steung saen , kampong thom , cambodia . this is the preferred habitat for clea species as it has a wide , muddy river bottom . such habitats are widespread across delta plains of southeast asian countries .
meanwhile , other clea snails will try to loosen the grip of the feeding predator on its prey by using their foot to
pull
the prey out , much like a tug - of - war game .
on the other hand , like all snails , clea helena and tylomelania spp . are vulnerable to predation when kept with large fish . cichlids , pufferfish , loaches and certain catfish ( e . g . , synodontis ) are likely to view clea helena and the smaller tylomelania as potential food . even if they don’t eat them outright , fish that like to peck at things may stress these snails sufficiently that they’ll cause damage and eventually death .
clea helena are known as assassin snails and snail - eating snails precisely because they’re so good at catching and killing small snails . are they worth using though ? in short , yes , but you will need quite a few of them .
besides malayan livebearing snails , clea helena will also eat other small snail species including physa spp . ( tadpole snails ) . they will also eat juvenile tylomelania snails , and that may be an issue if you want to keep them together .
clea helena is a predator , and it will eat any small snails it can catch . it will likely eat fish eggs too , and quite likely immobile ( “wriggler” ) fish fry too . but otherwise clea helena is an excellent community tank resident . it does not harm snails that are substantially larger than it is , and things like adult nerite snails as well as tylomelania seem to coexist amicably enough . fish are at no risk at all once mobile , and even livebearer fry are ignored .
these are true freshwater snails and do not need salt added to the water . but having said that , the authors experience is that both clea helena and tylomelania spp . tolerate slightly brackish water conditions ( around sg 1 . 003 ) perfectly well .
( of quadrasia crosse , 1886 ) smith e . a . ( 1895 ) observations on the genus clea , with the description of a new species . proceedings of the malacological society of london 1 : 251 - 253 . , available online at urltoken [ details ]
hi ! nice work you ' ve done here ! i ' m portuguese malacologist currently finishing my phd thesis on gastropods in the aquarium trade . clea helena was one of my studied species ! i wonder if you could contact me by email so we could exchange some thoughts ? rita . coelho @ urltoken kind regards , rita
like most other snails , clea helena and tylomelania spp . will not do well in water that is too soft or acidic . while the precise water chemistry values do not seem to be important , aim for moderately hard to hard water with a ph above neutral ( 10 - 20 degrees dh , ph 7 - 8 ) .
hello , i am trying to id a species of clea i collected in a hill - forest torrent in brunei . i think it might be c . nigricans . however , i found descriptions of other species that are rather similar ( c . funesta , c . bockii ) and would like to share some thoughts . could you pls send me a mail to gianluca . polgar @ urltoken
it is not possible to tell male and female clea helena apart , so to start breeding them , a small group will be necessary . when clea helena mates , pairs or groups of snails clamber over each other and seem to hold position like that for hours at a time . eventually the males and females separate , and the females go off to lay their eggs . eggs are deposited one at a time in tiny transparent blobs , usually on solid objects such as bogwood roots . hatching takes a few weeks , and it is fully six months before the juveniles are big enough ( around 8 mm ) to be seen actively hunting at the surface . before they get that big they are presumably hidden away in the sand feeding on whatever small organisms they find there . lifespan is around two years .
clea helena is a burrowing species , and does best in tanks with a sandy substrate . if nothing else , this gives the aquarist an opportunity to watch the natural behaviour of the species . it is also more likely to reproduce successfully in a tank with a sandy substrate since the juvenile snails seem to spend a lot of time hidden underground . perhaps they need to avoid being eaten by the adults ?
tylomelania spp . and clea helena have much to attract the aquarist keeping small , gentle freshwater fish . compared to the existing species on offer , these snails are far less likely to become a pest , and once settled in , hardy and easy to maintain . while we’re not quite at the stage of having a freshwater reef tank just yet , these snails are a good few steps in that direction !
hello i am gianluca , i am trying to id a clea that i think is c . nigricans , collected in a hill - forest torrent in brunei . however , the original description of c . nigricans adams , 1855 closely resembles that one of c . funesta and c . blockii . . . if anyone likes to share some thoughts , i would love to have a chat by email : gianluca . polgar @ urltoken cheers , gianluca
the assassin snail ( clea helena ) has been welcomed by fishkeepers as the single best all - around snail - killing animal in the hobby . existing choices were limited to things like pufferfish and the larger loaches , particularly botiine loaches , but these fish are often difficult to maintain , and in the case of puffers especially , tend to be nippy towards their tankmates . the assassin snail is very different . it is small , completely harmless towards fish and shrimps , and generally very easy to keep . it is also very pretty , bright yellow with chocolate brown stripes .
alright , the next big question is probably : how does it feed ? i have heard many who discovered them congregating around rotting carcasses of frogs , dead swiflets and bats near caves . personally , i have encountered a group of clea helena feeding on picnic leftovers of fried fish at water ' s edge in sungai jernih , perlis , malaysia . so , these buccinids are no different from their marine cousins - scavengers and predators at the same time . i ' ve brought some back home for further observations of their feeding behaviour . here ' s a photo - essay of it :
information on the african species is particularly void while asia ' s ones received more attention ( from the aquarium trade , not researchers ! ) . clea genus is widespread across southeast asia and have not been recorded elsewhere . it ' s abundance is notable especially in alluvial plains and around large water bodies like the irrawaddy delta ( myanmar ) , mekong river ( indochina countries ) , chao phraya river ( thailand ) and other major waterways and lakes of malaysia , brunei and indonesia ( sumatra , java , kalimantan ) . the question is - how did they managed to reach other rivers and lakes divided by tall mountain ranges and vast seas ?
on the scientific front though , little is known about this enigmatic group of snails . however , it is generally accepted that there are two genus of this family that somehow abandoned the sea in favour of creeks and ponds . the african species is categorised into the ( sub ) genus afrocanidia while asia ' s is grouped into the clea genus . now , this may shed some light to its origins . perhaps , they first appeared from a common ancestor when africa and south asia was in one piece ( called pangea ) 225 million years ago ? or did they adapted to freshwater separately ( convergent evolution ) since it is more likely to be a recent adaptation ?
the possible answer can be found when we turn the clock back to around 20 000 years ago . the waters of south china sea , gulf of siam , straits of malacca and java sea recede and is replaced by alternating grasslands and swamps . now , one would notice that major rivers were being drained out of this large peninsula , dubbed sundaland , by
mega rivers
( much like the present day amazonian basin ) . so , it ' s possible that the clea genus or its ancestor have had its early millenias conquering much of sundaland ' s freshwater systems before rising sea levels cut off many populations and from there each evolved into seperate species or subspecies .
tylomelania spp . are almost but not quite livebearers . again , males and females are separate , so for breeding purposes a group is required . there is no easy way to sex them . once mating has taken place , the female broods the eggs internally almost to the point when they are ready to hatch . the eggs are then released , and within an hour than juvenile snail crawls out from the shell . at this point the juvenile has a shell that is a good 5 mm in length , and can be reared alongside the adults without problems . they are , however , vulnerable to predation by clea helena , so while adults of both species can be mixed , you won’t get many tylomelania if they’re kept together .
adams a . ( 1855 ) . description of two new genera and several new species of mollusca , from the collection of hugh cuming , esq . proceedings of the zoological society of london . 23 : 119 - 124 . , available online at urltoken page ( s ) : 119 [ details ]
galindo , l . a . ; puillandre , n . ; utge , j . ; lozouet , p . ; bouchet , p . ( 2016 ) . the phylogeny and systematics of the nassariidae revisited ( gastropoda , buccinoidea ) . molecular phylogenetics and evolution . 99 : 337 - 353 . , available online at urltoken [ details ] available for editors [ request ]
( of quadrasia crosse , 1886 ) houbrick r . s . ( 1986 ) transfer of quadrasia from the planaxidae to the buccinidae ( mollusca : gastropoda : prosobranchia ) . proceedings of the biological society of washington 99 ( 2 ) : 359 - 362 . [ details ]
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the various species of tylomelania imported from the southeast asian island of sulawesi are not kept to do a job , but because they’re interesting and attractive . in the past aquarists have kept apple snails ( pomacea spp . ) but these don’t always do well . in the wild most apple snails spend a few months resting in the mud , but they can’t do this in an aquarium , and because of this seem to ‘burn up’ , dying within a year or so and never attaining full size . tylomelania spp . do much better in aquaria , and unlike apple snails , they do not eat plants , so can be kept in planted tanks without risk .
tylomelania are members of the family pachychilidae , a freshwater - dwelling group within the predominantly marine cerithioidea superfamily of gastropods . there are numerous tylomelania species , and telling them apart is difficult . many retailers simply sell them as tylomelania , or else under trade names such as sulawesi elephant snails , helmet snails , rabbit snails and various other names .
tylomelania spp . are primarily inhabitants of lakes and rivers . they are more scavengers than carnivores , and feed on various types of decaying organic matter besides carrion . they also eat some algae , though they are less dedicated algae - eaters than , say , nerite snails , which seem to eat nothing else .
what makes tylomelania so remarkable is their size and variety . their shells come in a range of shapes and sizes , the biggest ones more than 10 cm ( 4 inches ) in length . ornamentation consists of different arrangements of ribs and grooves . the soft body of the animal is variable too , and can be yellow , green , grey or black .
water quality is important , particularly in the case of tylomelania . these are not species for immature aquaria , and are best added after the aquarium has been running for at least a couple of months . unlike the other freshwater snails kept by hobbyists , such as apple snails , these are not air - breathing snails , and they will not do well in tanks with poor water circulation or inadequate oxygen .
tylomelania are less fussy and do well in tanks with either sand or gravel substrates . if sand is provided , they will root about a bit more naturally , and this is fun to watch , but they don’t seem overly bothered by gravel substrates . tylomelania will breed successfully in tanks with either type of substrate .
feeding these snails is extremely easy , since both species consume any meaty food they find , including uneaten fish food . to a degree then , they’re scavengers . but for optimal health they will need some food left out specifically for them . catfish pellets are a good staple , but these could be augmented with calcium - rich fare that will help them build their shells . wet - frozen brine shrimp , mysis and krill all seem to be very popular . small pieces of frozen lancefish are also welcomed , especially the more bony bits like the head that fish tend to ignore .
tylomelania spp . are essentially non - predatory so far as aquarium fish and invertebrates go .
good companions are things like tetras , non - nippy barbs , rainbowfish , livebearers , corydoras catfish , bristlenose catfish and so on .
tylomelania are excellent scavengers and a good choice for the aquarist after a snail that will consume uneaten fish food and organic detritus . they are especially good at cleaning up any leftover bones and shells , as well as things like shrimp moults .
of course no snail actually “cleans” an aquarium , and that remains the job of the filter ( as well as the weekly water changes ) . but tylomelania seem to be able to compete reasonably well with things like corydoras catfish , and aquarists might even consider using these snails , perhaps alongside shrimps , as the only bottom feeders in the aquarium .
brandt r . a . m . ( 1974 ) . the non - marine aquatic mollusca of thailand . archiv für molluskenkunde . 105 : i - iv , 1 - 423 . page ( s ) : 204 , pl . 15 fig . 69 [ details ]
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like all snails in the clade neogastropoda , snails in this genus are carnivorous .
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from sungai jernih , perlis , northern peninsula malaysia . note its difference from thai varieties offered in the aquarium trade .
is a very resilient snail . it can lay dormant for more than a month without food . in this stage , it usually buries or half - buries itself in the loose , sandy or muddy substrate .
when food ( meat or snail ) is detected , it prolongs it ' s proboscis ( siphon ) and crawls out to search for its quarry . occasionally , it will also react similarly when there is movement in the water ( especially if it lives in still waters most of the time . )
it will then wander around to locate the prey . however , it takes a straight path towards the prey if there are no others in the vicinity .
the first to reach the prey will grab it with its foot and inserts a thin , fleshy tube ( siphon ) into the snail and suck the animal within the shell .
( proably excreting digestive enzymes and dissolve the prey alive before consuming it . )
to finish its meal but that may be because of the miniature size of the prey . for larger size meals like frog carcasses , it might take a day or more to finish the entire body . most of the time , they will abandon their meal when they are full and return back when they ' re ready for the next meal .
after some time devouring its prey , other snails will lose interest and gradually retreats back to their hideouts , leaving the lucky snail and its meal alone . at last , when the meal is finished , the predator will crawl back to its own resting spot , leaving empty shells of the prey behind .
not surprisingly , buccinids aren ' t the only one which has migrated to freshwater environments in southeast asia . there are also genus
( thailand ) of pyramidellidae . so , who knows what more lurks in the muddy depths of these tropical rivers and lakes ?
the melvill - tomlin collection . parts . 50 , 51 , 52 , 53 , 54 . buccinacea ( pyrenidae , buccinidae , galeodidae , nassariidae and fasciolariidae ) .
maps of holocene sea level transgression and submerged lakes on the sunda shelf . the natural history journal of chulalongkorn university , supplement 2 : 1 - 44 , august 2006 .
ellen e . strong , oliver gargominy , winston f . ponde , phillippe bouchet , 2008
global diversity of gastropods ( gastropoda ; mollusca ) in freshwater . hydrobiologia ( 2008 ) 595 : 149–166
according to the report : ellen e . strong , oliver gargominy , winston f . ponde , phillippe bouchet , 2008 global diversity of gastropods ( gastropoda ; mollusca ) in freshwater . hydrobiologia ( 2008 ) 595 : 149–166 . freshwater buccinids are first recorded in the fossil assemblages of the miocene period ( approximately 23 - 5 million years ago ) .
a young nature - lover aspiring to be a malacologist . inspired by the amazing biodiversity of tropical rainforests and coral reefs ( snails , clams and slugs in particular ) ; intrigued by the fields of paleotology , geology and many other fields that suffix with
- logy
; motivated by the never ending discoveries of nature and the ecology within . traveled extensively around southeast asia & beyond . this blog showcases snapshots of my discoveries , explorations , views and admiration of the intricacies in molluscs and nature while on the journey towards achieving my childhood dream .
last wednesday i received an email from mike cole of cole ecological , forwarded by our good buddy tim pearce . attached to mike’s message was the jpeg bel . . .
the ubin community came together to celebrate singapore ' s last unspoilt island from 26 may ( sat ) to 24 jun ( sun ) 2018 . here ' s a look back at pesta ubin 201 . . .
there are a lot of cases where you may need the help of a committed locksmith so it is of utmost importance that you have the contact number of a reliable . . .
red - legged pademelons ( * thylogale stigmatica * ) are not sociable animals , but they put up with each other . but every now and then , especially towards the en . . .
to come out again , mr / ms mantis shrimp… . . and true enough , patience paid off and here’s he / she peeking out of his / her hole ! more of the mantis shrimp and . . .
today is halloween . in my own culture , it is never part of our ' habit ' to celebrate this event . but in my adopted country , this is big ! the children are lo . . .
article id : 2013 - 07 - 22 - wetecol * jamilah , ms * & muhammad razali salam coastal biodiversity and conservation research group department of biological scien . . .
the 15th meeting of the mid - atlantic malacologists took place yesterday at the delaware museum of natural history ( dmnh ) in wilmington , delaware . i counted . . .
the ariophantid * hemiplecta belerang * sp . nov . from south sumatra is described in this paper . it is compared with its closest congeners , from which it is g . . .
snakes ! tigers ! lizards ! pangolins ! bears ! calling all wildlife in the forest ! run for your lives ! for the wildlife kingpin is freed - again . . . old habits . . .
i pick my way along the beach the sky is blue , the tide is out , exposed pools glitter ; down i reach to touch a sea hare on the snout . * – * ( perhaps it’s not . . .
borneo is totally smaller than india or australia , but very rich with biodiversity . i am interested on terrestrial snail fauna especially the micro - terres . . .
19 october 2009 after the not - so - satisfying snorkeling experience at bare island in the morning , i went snorkeling at little bay in the afternoon and had a . . .
this is a short article written on coral reef ecosystem for ekomar coffeetable book : ) .
coral reef ecosystem is the most diverse ecosystem in the sea . it . . .
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