confuciusornis is a genus of primitive crow-sized birds from the early cretaceous yixian and jiufotang formations of china , dating from 125 to 120 million years ago .

like modern birds , confuciusornis had a toothless beak , but close relatives of modern birds such as hesperornis and ichthyornis were toothed , indicating that the loss of teeth occurred convergently in confuciusornis and living birds .

it is the oldest known bird to have a beak .

it was named after the chinese moral philosopher confucius ( 551 – 479 bc ) .

confuciusornis is one of the most abundant vertebrates found in the yixian formation , and several hundred complete , articulated specimens have been found .

confuciusornis

cellular preservation of musculoskeletal specializations in the cretaceous bird confuciusornis . tof - sims dataset
a confuciusornis with long tail feathers . photo by laikayiu , image from wikipedia .
a three - dimensional , computer generated image of the lower right leg of confuciusornis .
name : confuciusornis sanctus , c . dui , c . feducciai , c . jianchangensis
confuciusornis was a beautiful bird that lived around 120 million years ago . scientists believe that the birds probably evolved from dinosaurs . confuciusornis still had many characteristics in common with dinosaurs , such as clawed hands . however , confuciusornis was very much a bird . with a toothless , hard beak and no tail , confuciusornis would have not been all that different from modern birds . confuciusornis is one of the first known birds to have a wishbone .
“archeopteryx and confuciusornis are still at a very early stage in the evolution of flight . ”
the flight feathers of early mesozoic birds archaeopteryx and confuciusornis were too weak to support powered flight .
cellular preservation of musculoskeletal specializations in the cretaceous bird confuciusornis . additional s . e . m . image dataset
martin ld , zhou z ( 1998 ) confuciusornis sanctus compared to archaeopteryx lithographica . naturwissenchaften 85 : 286–289 .
“this pushes the origin of flapping flight to after archaeopteryx and confuciusornis . it must have come much later . ”
a dinosaur a day · confuciusornis sanctus , c . dui , c . feducciai , c . . . .
photos show entombing poses typical of victims of pyroclastic flows ( a , psittacosaurus ; b and c , confuciusornis ) .
martin originally described confuciusornis 12 years ago with zhou zhonghe from the ivpp , a co - author of the eoconfuciusornis paper .
previous studies ( e . g . [ 1 , 3 ] ) visualized only the osteology and / or plumage of confuciusornis , however our study represents a first look at other soft tissues such as scales , dermal complexes ( patagia ) , ligaments , tendons and musculature of confuciusornis . this new information indicates that confuciusornis has a suite of relatively modern soft tissue structures that are more advanced than may be expected . new information about the wing shape of confuciusornis also reveals more about how this enigmatic bird may have flown .
“the fossilsof confuciusornis and archaeopteryx suggest flight and at this stage it would be a brave person to say they couldn’t fly” he says .
paul gs . comment on “narrow primary feather rachises in confuciusornis and archaeopteryx suggest poor flight ability” . science . 2010 ; 330 : 320 .
an examination of fossilised feathers belonging to the ancient birds confuciusornis and archaeopteryx shows their wings were too weak to support the birds in flight .
chinsamy , a . , chiappe , l . , marugán - lobón , j . , chunling , g . , fengjiao , z . 2013 . gender identification of the mesozoic bird confuciusornis sanctus gender identification of the mesozoic bird confuciusornis sanctus . nature communications . 4 , 1381 . doi : 10 . 1038 / ncomms2377
backscattered electron - microscope images show carbonized soft tissues ( dark materials ) on the fossils ( a and b , psittacosaurus ; c and d , confuciusornis ) .
photomicrographs of thin sections show abrasive pits , missing bone material ( arrows ) , and cracks at bone edges ( a , psittacosaurus ; b , confuciusornis ) .
whereas most living birds ( including the ostrich ) reach full size within a year , the internal bone structure of confuciusornis shows that it grew more slowly . like other small dinosaurs , confuciusornis probably took several years to mature . this evidence suggests that birds apparently did not evolve their rapid growth rates until sometime in the late cretaceous .
paleontologists consider archaeopteryx and confuciusornis to be “birds” insofar as they possess feathers and other avian features , but they are not members of any living group of birds . …
although the confuciusornis family were the first and most primitive birds to evolve toothless bills and dominated the yixian landscape , they vanished from the fossil record without leaving descendants .
in 1995 , lianhai hou and zhonghe zhou , two paleontologists from the vertebrate paleontology institute in china , discovered a new fossil bird they named confuciusornis . this winged vertebrate—the same age as archaeopteryx , approximately 140 million years old and long considered to be the earliest ancestor of all birds and regarded as semi - reptilian . yet confuciusornis bore a [ … ]
here , we report cellular - level preservation of tendon - and cartilage - like tissues from the lower hindlimb of early cretaceous confuciusornis . the digital flexor tendons passed through cartilages , cartilaginous cristae and ridges on the plantar side of the distal tibiotarsus and proximal tarsometatarsus , as in extant birds . in particular , fibrocartilaginous and cartilaginous structures on the plantar surface of the ankle joint of confuciusornis may indicate a more crouched hindlimb posture . recognition of these specialized soft tissues in confuciusornis is enabled by our combination of imaging and chemical analyses applied to an exceptionally preserved fossil .
hou , l ; zhou , z ; gu , y . & zhang , h . ( 1995 ) . [ description of confuciusornis sanctus ] . chinese science bulletin 10 : 61–63 .
confuciusornis was a strong flyer , with flight muscles anchored on the wing by a large ridge of bone known as the deltopectoral crest , and on the body by a large fused sternum .
despite hundreds of excellent fossils of confuciusornis , the most abundant group of birds in the early cretaceous , ‘jehol biota’ in china , there is yet no indication of the food choice of these birds . here , we describe fish remains preserved in the alimentary system of a specimen of confuciusornis sanctus from the jiufotang formation . this find is about five million years younger than all previously published confuciusornithid birds from the yixian formation . although it is unknown how common fish was in the diet of confuciusornis , the find does not support previous hypotheses that it fed on plants or grain .
a , b ; block containing confuciusornis ( blue ) and unidentified ornithischian ( red ) remains . c , close up of confuciusornis sternal and pectoral elements ( small box in b ) ; d , e ; associated skeleton of confuciusornis ( large box in b ) ; f , proximal confuciusornis humerus ( arrow in figure 2 ) . abbreviations : c , carpal ; dr , dorsal rib ; fu , furcula ; gs , gastralia ; h , humerus ; il , ilium ; is , ischium ; mu , manual ungula ; ms , miscellaneous ornithischian bone ; ph , phalanx ; pu , pubis ; ra , radius ; sc , scapulocoracoid ; st , sternum . scale bars in a , b equal 10 cm in 1 cm increments ; c , f in 1 mm increments .
with a pair of separate sternal plates and a smaller deltopectoral crest , eoconfuciusornis is more advanced than archaeopteryx , and the most primitive , as well as the earliest , member of the confuciusornis family .
for their latest paper dr nudds and dr dyke applied a novel biomechanical analysis to the flight feathers of the early birds archaeopteryx and confuciusornis to find out if they were strong enough to allow flight .
zheng x , xu x , zhou z , miao d , zhang f . comment on “narrow primary feather rachises in confuciusornis and archaeopteryx suggest poor flight ability” . science . 2010 ; 330 , 320 .
l . hou and l . d . martin . 1999 . a diapsid skull in a new species of the primitive bird < i > confuciusornis < / i > . nature 399 : 679 - 682
figure 17 . 11 two examples of the early cretaceous bird confuciusornis from liaoning , china , showing a male ( below , with long tail streamers ) and a female . ( courtsey of zhou zhonghe . )
ancient bird confuciusornis when feathered dinosaurs roamed the land , true birds soared through the liaoning skies . some were as big as albatrosses ; others , such as this confuciusornis , were more the size of pigeons . this fossil , dating to about 120 million years ago , reveals characteristics that make confuciusornis a mix of primitive ( more dinosaur - like ) and advanced ( modern bird - like ) traits : like dinosaurs and the oldest known bird , archaeopteryx , it has three fingers that are not fused into a single element , but like modern birds , it has a toothless beak and a well - developed shoulder girdle to power flight .
confuciusornis was a herbivore . it lived in the cretaceous period and inhabited asia . its fossils have been found in places such as inner mongolia ( china ) , hebei ( china ) and liaoning ( china ) .
a hugely enlarged reconstruction of the eumelanin molecule with its distinctive central absorber atom of copper hovers above a srs - xrf map of confuciusornis , whose feather pigments are resolved in copper ( false coloured in red ) .
local farmers living in or near the chaomidianzi formation collected the first known remains of confuciusornis . although a good number of specimens have been deposited in chinese museums , many more have been sold illegally to commercial fossil dealers .
slac news centre 2011 . x - rays reveal patterns in the plumage of the first birds . urltoken — media summary of the work on confuciusornis sanctus at the stanford linear accelerator , including a video on the study .
the new find is closely related to confuciusornis – the most abundant yixian fossil bird , with thousands of examples known . the two share skeletal features , as well as toothless horny bills and distinctive long paired tail feathers .
citation : falk ar , kaye tg , zhou z , burnham da ( 2016 ) laser fluorescence illuminates the soft tissue and life habits of the early cretaceous bird confuciusornis . plos one 11 ( 12 ) : e0167284 . urltoken
how to cite this article : jiang , b . et al . cellular preservation of musculoskeletal specializations in the cretaceous bird confuciusornis . nat . commun . 8 , 14779 doi : 10 . 1038 / ncomms14779 ( 2017 ) .
recent cladistic analyses suggest that confuciusornis is the most primitive pygostylian bird ; it has a more primitive skull than archaeopteryx , but it is the first known bird to have lost the long tail of archaeopteryx and develop fused tail vertebrae ( a pygostyle ) . [ 11 ] one controversial study concluded that confuciusornis may be more closely related to microraptor and other dromaeosaurs than to archaeopteryx , but this study was criticized on methodological grounds ( mayr et al . , 2005 ) .
these birds were about a foot long and most likely weighed under a pound . like modern birds , they had a beak and had claws they could walk on , but they also had claws at the end of their wings – on its hands . some of the most fascinating facts about confuciusornis is the speed at which they grew . most modern birds reach adulthood withing the first year of life . however , it is believed confuciusornis grew at a much slower rate .
new findings presented here concerning the skull of confuciusornis reveal the intact diapsid pattern of the temporal region in this bird . thus the skull of confuciusornis combines the plesiomorphic condition of two complete temporal fenestrae with an edentulous avian bill . this information strengthens the view that many presumed “typical” avian features evolved independently several times and that the phylogenetic tree of birds is not a straight sequence of anagenetic stages but rather a “bush” with parallel pathways leading to varying mosaics of plesiomorphies and apomorphies .
what was the diet of confuciusornis like ? well , while it’s not completely known what it ate , scientists can make a pretty good guess on their diet . it is believed that these birds probably lived off of seeds and maybe insects .
the avian is a perfect candidate for such a study . many of these birds are preserved with intact feathers , and their plumage comes in two forms . some confuciusornis are preserved with two elongated tail feathers , while others are not . researchers have debated whether these ornaments are indicators of sexual dimorphism , species differences , individual variation , or simply different molt stages , but bone histology has finally solved the mystery . the confuciusornis with the long feathers were males , while females lacked the flashy adornments .
one of a series of spectacular chinese fossil discoveries made over the past 20 or so years , confuciusornis was a true find : the first identified prehistoric bird with a true beak ( a subsequent discovery , of the earlier , similar eoconfuciusornis , was made a few years later ) . unlike other flying creatures of its era , confuciusornis had no teeth - - which , along with its feathers and curved claws suited for sitting high up in trees , makes it one of the most unmistakably birdlike creatures of the cretaceous period . ( this arboreal habit didn ' t spare it from predation , however ; recently , paleontologists unearthed the fossil of a much bigger dino - bird , sinocalliopteryx , harboring the remains of three confuciusornis specimens in its gut ! )
in this paper we report the discovery of non - plumage soft tissues in confuciusornis , a basal beaked bird from the early cretaceous jehol biota in northeastern china . various soft tissues are visualized and interpreted through the use of laser - stimulated fluorescence , providing much novel anatomical information about this early bird , specifically reticulate scales covering the feet , and the well - developed and robust pro - and postpatagium . we also include a direct comparison between the forelimb soft tissues of confuciusornis and modern avian patagia . furthermore , apparently large , fleshy phalangeal pads are preserved on the feet . the reticulate scales , robust phalangeal pads as well as the highly recurved pedal claws strongly support confuciusornis as an arboreal bird . reticulate scales are more rounded than scutate scales and do not overlap , thus allowing for more flexibility in the toe . the extent of the pro - and postpatagium and the robust primary feather rachises are evidence that confuciusornis was capable of powered flight , contrary to previous reports suggesting otherwise . a unique avian wing shape is also reconstructed based on plumage preserved . these soft tissues combined indicate an arboreal bird with the capacity for short - term ( non - migratory ) flight , and suggest that , although primitive , confuciusornis already possessed many relatively advanced avian anatomical characteristics .
results include important species such as the oldest beaked bird yet found , the 120 million year old confuciusornis sanctus , and also the 110 million year old gansus yumenensis , which looks similar to the modern grebe and represents the oldest example of modern birds .
full reference : l . hou , l . d . martin , z . zhou , a . feduccia , and f . zhang . 1999 . a diapsid skull in a new species of the primitive bird confuciusornis . nature 399 : 679 - 682
the fossil birds archaeopteryx and confuciusornis had feathered wings resembling those of living birds , but their flight capabilities remain uncertain . analysis of the rachises of their primary feathers shows that the rachises were much thinner and weaker than those of modern birds , and thus the birds were not capable of flight . only if the primary feather rachises were solid in cross - section ( the strongest structural configuration ) , and not hollow as in living birds , would flight have been possible . hence , if archaeopteryx and confuciusornis were flapping flyers , they must have had a feather structure that was fundamentally different from that of living birds . alternatively , if they were only gliders , then the flapping wing stroke must have appeared after the divergence of confuciusornis , likely within the enantiornithine or ornithurine radiations .
the fossil birds archaeopteryx and confuciusornis had feathered wings resembling those of living birds , but their flight capabilities remain uncertain . analysis of the rachises of their primary feathers shows that the rachises were much thinner and weaker than those of modern birds , and thus the birds were not capable of flight . only if the primary feather rachises were solid in cross - section ( the strongest structural configuration ) , and not hollow as in living birds , would flight have been possible . hence , if archaeopteryx and confuciusornis were flapping flyers , they must have had a feather structure that was fundamentally different from that of living birds . alternatively , if they were only gliders , then the flapping wing stroke must have appeared after the divergence of confuciusornis , likely within the enantiornithine or ornithurine radiations .
although this bird could fly and probably hung around the tops of trees most of the time , that didn’t spare it from being hunted by dinosaurs . scientists know this because they recently discovered a sinocalliopteryx dinosaur which contained the remains of 3 confuciusornis birds in its belly !
the researchers also sampled the bones of three confuciusornis preserved with long tail feathers . these specimens didn’t contain medullary bone . while it’s possible that these were females that were not laying eggs around the time of death , the presence of medullary bone in the non - ornamented form and its absence in the ornamented ones is consistent with the idea that the feathers underscore a real sex difference . and since relatively small confuciusornis have been found with long tail feathers , chinsamy and coauthors point out , these birds probably started reproducing relatively early in life .
the eruptions occurred across northern china from roughly 120 to 130 million years ago . in the study , the international team examined the ash encasing 14 well - preserved fossils from five bone beds , including the crow - size bird confuciusornis and the parrot - faced dinosaur psittacosaurus .
^ a b nudds , r . l . and dyke , g . j ( 2010 ) .
narrow primary feather rachises in confuciusornis and archaeopteryx suggest poor flight ability .
science , 328 ( 5980 ) : 887 . doi : 10 . 1126 / science . 1188895
the unprepared confuciusornis specimen mes - nju 57002 was identified by microct scanning using a 2010 ge phoenix v | tome | x s240 system . microct scan data are available 41 . the specimen was compared with others ( supplementary table 1 ) to confirm its identity and adult status .
dr nudds adds : “our analysis also shows that confuciusornis , which is younger by 25 million years , was worse at flying than archaeopteryx . this raises the further question of lineage - did the dinosaur - bird line branch off , giving rise to flying and flightless birds ? ”
in early 2010 , a group of scientists led by zhang fucheng examined fossils with preserved melanosomes ( organelles which contain colors ) . by studying such fossils with an electron microscope , they found melanosomes preserved in a fossil confuciusornis specimen , ivpp v13171 . [ 8 ] the melanosomes where of two types , eumelanosomes and pheomelanosomes . this indicates that confuciusornis had hues of grey , red / brown and black , possibly something like the modern zebra finch . it was also the first time an early bird fossil has been shown to contain preserved pheomelanosomes . [ 9 ] [ 10 ]
with the recent discoveries of magnificently preserved fossils from the early cretaceous konservat - lagerstätten ( jehol biota ) of northeastern china—many of which exhibit exceptional soft - tissue preservation , including plumage—a rare opportunity to study the soft - tissue anatomy of fossil birds arises . confuciusornis has been well studied with regards to its osteology ( e . g . , [ 1 – 4 ] ) and some portions of its plumage . much about the plumage , however , has yet to be adequately described , and much of the current research has focused on the primary flight feathers and the enigmatic , long , paired tail feathers [ 5 – 7 ] . the paired tail feathers of confuciusornis were suggested to represent sexual dimorphism [ 1 ] and their exact morphology has been the subject of debate ( e . g . , [ 7 ] ) . the primary feathers of confuciusornis were interpreted as thin and weak , and therefore unable to support flapping flight [ 5 ] . furthermore , the primary feathers of confuciusornis were much longer relative to the arm bones than what is found in modern birds , and previous studies suggested that confuciusornis possessed a long and pointed , fast - flying type of wing morphology [ 6 ] . although there have been studies refuting the suggestion of the thin and weak primary rachises [ 8 , 9 ] , some studies still maintain that the feathers were too weak for flapping flight ( e . g . , [ 6 ] ) .
^ paul , g . s . ( 2010 ) .
comment on ' narrow primary feather rachises in confuciusornis and archaeopteryx suggest poor flight ability . '
science , 330 ( 6002 ) : 320 . ( 15 october 2010 ) . doi : 10 . 1126 / science . 1192963
has asymmetrical flight feathers and lacks teeth in its mouth , so it is considered the oldest known beaked bird . the jurassic - aged fossil bird archaeopteryx , from the solnhofen limestone of germany , does have teeth . unlike modern birds , confuciusornis has three clawed fingers on the leading edge of each wing . hundreds of specimens have been found , often in close proximity on bedding planes . these mass mortality beds consistent with the volcanic ash burial model that accounts for the exquisite preservation of jehol fossils . confuciusornis fossils frequently have well preserved wing , tail , body , and neck feathers . some confuciusornis specimens have exceedingly long tail feathers . such long - tailed fossils are often found in close proximity to individuals having very short tail feathers . the chinese have concluded that this may be evidence for sexual dimorphism in the species , and the long - tailed individuals are inferred to be males .
name : confuciusornis  ( confucius bird )  . phonetic : kon - few - shus - or - nis . named by : zhou zhonge ,  hu yoaming ,  hou lianhai & gu youcai  -  1995 . synonyms : confuciusornis chuonzhous ,  confuciusornis suniae .  possibly jinzhouornis . classification : chordata ,  aves ,  avebrevicauda ,  pygostylia ,  confuciusornithiformes ,  confuciusornithidae . species : c .  sanctus ( type )  ,   c .  dui ,  c .  feducciai ,  c .  jianchangensis . diet : uncertain but probably at least partially piscivorous .  see main text . size : wingspan about 70 centimetres . known locations : china  -  yixian formation & jiufotang formation . time period : barremian / aptian of the cretaceous . fossil representation : remains of literally hundreds of individuals ,  many complete with feather detail preservation .
confuciusornis sanctus , the oldest bird with a beak , from liaoning province , china . this species retained some of the primitive features seen in archaeoptyeryx , such as free claws on the wing , along with more advanced features such as the lack of teeth in the bill . i mage from urltoken .
confuciusornis was a crow - sized bird that had a small triangular snout and , unlike archaeopteryx , lacked any teeth . fossilised remnants of the birds are among the most common found in the liaoning deposits in china , suggesting they may have lived in large colonies on the shores of the ancient lake .
since the description of confuciusornis ( the oldest beaked bird ) in1995 , based on three partial specimens , large numbers of complete skeletons have been recovered , . most new material of confuciusornis , can be assigned to a single sexually dimorphic species , c . sanctus . here we report a new species based on a remarkably well preserved skeleton with feathers and , for the first time in the mesozoic record , direct evidence of the shape of a horny beak . it has a complete and large preserved postorbital that has a broad contact with the jugal bone . this character is presently only known in confuciusornis , and may confirm previous suggestions of a postorbital in archaeopteryx . the squamosal is in tight contact with the postorbital . these two bones form an arch dividing the upper and lower temporal fenestrae , as in other diapsid reptiles . the presence of a typical diapsid cheek region with two openings in confuciusornis may preclude the presence of prokinesis ( upper jaw mobility against the braincase and orbital area ) , a feeding adaptation found in most modern birds . the presence of a horny beak , characteristic of modern birds , coupled with a primitive temporal region provides new evidence for a mosaic pattern in the early evolution of birds .
the hindlimb of theropod dinosaurs changed appreciably in the lineage leading to extant birds , becoming more ‘crouched ' in association with changes to body shape and gait dynamics . this postural evolution included anatomical changes of the foot and ankle , altering the moment arms and control of the muscles that manipulated the tarsometatarsus and digits , but the timing of these changes is unknown . here , we report cellular - level preservation of tendon - and cartilage - like tissues from the lower hindlimb of early cretaceous confuciusornis . the digital flexor tendons passed through cartilages , cartilaginous cristae and ridges on the plantar side of the distal tibiotarsus and proximal tarsometatarsus , as in extant birds . in particular , fibrocartilaginous and cartilaginous structures on the plantar surface of the ankle joint of confuciusornis may indicate a more crouched hindlimb posture . recognition of these specialized soft tissues in confuciusornis is enabled by our combination of imaging and chemical analyses applied to an exceptionally preserved fossil .
since the description of confuciusornis ( the oldest beaked bird ) in1995 , based on three partial specimens , large numbers of complete skeletons have been recovered 1 , 2 . most new material of confuciusornis 3 , 4 can be assigned to a single sexually dimorphic species , c . sanctus . here we report a new species based on a remarkably well preserved skeleton with feathers and , for the first time in the mesozoic record , direct evidence of the shape of a horny beak . it has a complete and large preserved postorbital that has a broad contact with the jugal bone . this character is presently only known in confuciusornis , and may confirm previous suggestions of a postorbital in archaeopteryx 5 . the squamosal is in tight contact with the postorbital . these two bones form an arch dividing the upper and lower temporal fenestrae , as in other diapsid reptiles 6 . the presence of a typical diapsid cheek region with two openings in confuciusornis may preclude the presence of prokinesis ( upper jaw mobility against the braincase and orbital area ) , a feeding adaptation found in most modern birds . the presence of a horny beak , characteristic of modern birds , coupled with a primitive temporal region provides new evidence for a mosaic pattern in the early evolution of birds .
there are immature specimens known , and from the analysis of bone growth patterns of young adults it has been estimated that confuciusornis reached maturity somewhat slower than extant small birds , but faster than advanced dinosaurs ( de ricqlès et al . , 2003 ) , which might indicate an omnivorous diet similar to modern crows .
robert nudds and gareth dyke , at the universities of manchester and dublin respectively , took measurements of the feather structure of confuciusornis , which lived in the early cretaceous 120m years ago , and archaeopteryx , considered to be the first bird species to emerge on earth in the late jurassic , around 145m years ago .
dalsätt , j ; zhou , z ; zhang , f . & ericson , per g . p . ( 2006 ) . food remains in confuciusornis sanctus suggest a fish diet . naturwissenschaften 93 ( 9 ) : 444–446 . doi : 10 . 1007 / s00114 - 006 - 0125 - y ( html abstract )
university of cape town histology expert anusuya chinsamy and colleagues have undertaken just such a study , published this week in nature communications . instead of a non - avian dinosaur , though , the researchers picked confuciusornis sanctus – an early bird preserved by the dozens in the 125 to 140 million year old rock of china .
the 1993 discovery of confuciusornis , in china , was big news : this was the first identified prehistoric bird with a toothless beak , and thus bore a marked resemblance to modern birds . as is so often the case , though , confuciusornis has since been supplanted in the record books by an even earlier toothless ancestor of the cretaceous period , eoconfuciusornis , which resembled a scaled - down version of its more famous relative . like many birds recently discovered in china , the
type fossil
of eoconfuciusornis bears evidence of feathers , though the specimen was otherwise
compressed
( the fancy word paleontologists use for
crushed .
)
because confuciusornis is such a common fossil in the liaoning deposits , scientists now speculate about vast colonies that may have lived on the shores of the ancient chinese lake . of all the feathered dinosaurs , confuciusornis is the oldest to exhibit a nearly - modern flight apparatus . it still had fully - functional raptorial claws on its thumb and middle fingers , but its index finger  the finger that supports the flight feathers  was composed of broad , flat bones and a reduced claw . there are several anatomical peculiarities , including flight feathers that are longer than the body , which indicate that it had already diverged from the direct line leading to birds .
some researchers classify enantiornithes along with the true birds in the class aves , but those that use the more restrictive crown group definition of aves place them in the more inclusive avialae . enantiornithes were more advanced than archaeopteryx or confuciusornis , but in several respects more primitive than all modern birds , perhaps following an intermediate evolutionary path .
“the new discovery gives us a span of 11 million years of history” for the confuciusornis family , long enough to show patterns of evolution , says mike benton of the university of bristol , uk , co - author of a description of eoconfuciusornis with palaeontologists from the institute of vertebrate paleontology and paleoanthropology ( ivpp ) in beijing .
zhou z , farlow j . flight capability and habits of confuciusornis . in : j gauthier and lf gall editors . new perspectives on the origin and early evolution of birds ; proceedings of the international symposium in honor of john . h ostrom . new haven , cn usa : yale university press . 2001 ; pp . 237–254 .
confuciusornis lived in some of the most complex and well feathered ecosystems of the early cretaceous , alongside many other dinosaurs . as shown in the above image , it was probably preyed upon by some of them , such as sinocalliopteryx . in the yixian , confuciusornis lived alongside bolong , jeholosaurus , jinzhousaurus , liaoceratops , liaoningosaurus , psittacosaurus , archaeorhynchus , bohaiornis , changchengornis , eoenantiornis , dalingheornis , jinzhouornis , jixiangornis , hongshanornis , liaoningornis , liaoxiornis , lingyuanornis , longicrusavis , longirostravis , shanweiniao , zhongornis , graciliraptor , mei , sinornithosaurus , sinovenator , sinusonasus , tianyuraptor , zhenyuanlong , beipiaosaurus , caudipteryx , dilong , hexing , huaxiagnathus , incisivosaurus , ningyuansaurus , protarchaeopteryx , shenzhousaurus , similcaudipteryx , sinocalliopteryx , sinosauropteryx , yixianosaurus , yutyrannus , dongbeititan , and many pterosaurs , indicating a vibrant community for flying and gliding animals . in the jiufotang , confuciusornis lived alongside dinosaurs such as chuanqilong , psittacosaurus , alethoalaornis , boluochia , cathayornis , cuspirostrisornis , dapingfangornis , eocathayornis , graciliornis , huoshanornis , largirostornis , longchengornis , longipteryx , rapaxavis , sirnornis , xiangornis , chaoyangia , jianchangornis , parahongshanornis , schizooura , songlingornis , yanornis , yixianornis , dalianraptor , jeholornis , microraptor , omnivoropteryx , sapeornis , shenshiornis , similicaudipteryx , sinotyrannus , and zhongjianornis . despite all this competition from other gliding animals , the extreme abundance of confuciusornis indicates that it was a staple in thse communities .
here , we document a fossil of an early cretaceous bird , confuciusornis sanctus , which has some strikingly well - preserved soft tissues around its ankle joint . microscopic analyses of these tissues indicate that they include tendons or ligaments , fibrocartilages and articular cartilages , with microstructure evident at the cellular level . further chemical analyses reveal that even some of the original molecular residues of these soft tissues may remain , such as fragments of amino acids from collagen , particularly in the fibrocartilage . this concurs with accruing evidence that some biomolecules may survive , under exceptional circumstances , over many millions of years 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 . our reconstruction of the soft tissues around the ankle joint in this confuciusornis specimen leads to the conclusion that confuciusornis had evolved a more derived form and , presumably , function of the ankle region ( for example , neomorphic , rudimentary tibial cartilage and hypotarsus ) , revealing new details of how early birds began to adopt more crouched hindlimb postures .
however , just because confuciusornis looked like a modern bird doesn ' t mean it ' s the great - great - grandfather ( or grandmother ) of every pigeon , eagle and owl living today . there ' s no reason primitive flying reptiles couldn ' t have independently evolved birdlike characteristics such as feathers and beaks - - so the confucius bird may well have a been a striking
dead end
in avian evolution . ( in a new development , researchers have determined - - based on an analysis of preserved pigment cells - - that the feathers of confuciusornis were arranged in a mottled pattern of black , brown and white patches , a bit like a tabby cat . )
the paradise kingfishers ( genus tanysiptera ) of modern australia and new guinea have elongated
racket plumes
as their central tail feathers , giving them a superficial resemblance to confuciusornis . these kingfishers also take fish as prey , but they are not specialized fishers . they take many insects and other small prey from their forest habitat . [ 7 ]
the researchers then reconsidered this evidence in light of the whole anatomy of the confuciusornis leg , and that of its cousins from earlier dinosaurs to extinct and even modern birds . using this data , the team were able to obtain more information that potentially maps out how the straight - limbed ancestors of birds ( theropod dinosaurs ) , evolved the crouching gait .
as previously reported ( e . g . , [ 6 ] ) the primary feathers of confuciusornis are exceptionally long in relation to the forearm , however , the relative length of each individual primary , especially the outermost primaries , is different than has been previously reported . due to the relative length of the primaries , the wing shape is much broader and rounder than previously suggested . the 10th ( outermost ) primary of confuciusornis is less than half the length of the 9th primary , which in turn is shorter than the 8th primary ( fig 1b ) . the overall length of the secondaries in comparison to the primaries is also much greater than what is seen in most fast - flying birds ( fig 6 ) and results in a completely novel wing shape that is far different than previous reconstructions have suggested [ 22 ] . this rounder , broader morphology is more similar to that seen in both forest - dwelling and soaring birds [ 23 ] , however the wing shape of confuciusornis is unlike any known modern avian wing morphology ( e . g . , fig 6b–6e ) .
figure 3 - visual image ( a ) of the bird confuciusornis sanctus and its elemental map produced by x - ray fluorescence ( b ) . copper is shown in red , calcium in blue and zinc in green . ( c ) black and white artistic reconstruction of the bird ( by richard hartley ) . images from wogelius et al . ( see further reading ) .
confuciusornis was potentially an omnivore like modern crows , and it had a pointed , toothless beak that was relatively heavy built and immobile . the exact diet of confuciusornis , however , has long been under debate and scrutiny . no gastroliths have been found associated with the genus , indicating that it probably did not feed exclusively on plant matter . it is possible that it fed on fish , given the association of fossil fish bones found in a cluster where the crop would be found in modern birds . it also may have eaten insects and other small prey in its forest habitat . coloration has been determined from melanosomes and metals in the feathers , determining that it had darkly colored body and upper wing feathers , and the other wing feathers were potentially white .
although confuciusornis did not possess a large bony keel to support the pectoralis muscle as in modern birds , and therefore was not capable of powerful flight for extended periods , it still had the same anatomical features that allow for flapping flight in modern birds save for the triosseal canal . these features include a sternal keel ( although it is small and restricted , see [ 36 ] ) , and a large deltopectoral crest that would have allowed for larger deltoideus muscles for a more powerful upstroke . the pectoralis muscle also inserts on the ventral side of the deltopectoral crest [ 30 ] . this indicates that although confuciusornis could not rotate the arm behind the body in the upstroke portion of the flight stroke , it could still conduct flapping flight on the downstroke and recovery portion of the upstroke . the thick , deep postpatagium on the fingers would provide a strong anchoring surface for the long , thick calami of the primary feathers . the robust and extensive propatagium would provide powerful lift in concert with the long primaries . based on the evidence illuminated by laser fluorescence , confuciusornis is unequivocally an arboreal bird with the capacity for short term ( non - migratory ) powered flight . if confuciusornis , a primitive bird quite basal on the avian tree ( e . g . see [ 39 ] ) , possessed a suite of characters so modern , it suggests that these features arose much earlier than perhaps previously implied . if that is so , then earlier rocks may contain the answers to many questions about the origin and early evolution of birds .
confuciusornis held a number of physical characteristics in common with modern birds but possessed some striking differences . beautifully preserved specimens show impressions of its feathers , from which it can be inferred that the wings were of comparable size to those of similar flying birds today . unlike modern birds , however , the forearm of confuciusornis was shorter than both its hand and upper arm bone ( humerus ) . it also retained the feature of having three free fingers on the hand , like archaeopteryx and other theropod dinosaurs . in contrast , the fingers of more - derived birds are fused into an immobile element . confuciusornis had a short tail , a common feature in modern birds , and its caudal vertebrae were reduced in size and number . the terminal vertebrae were fused to form a structure known as the pygostyle . in some specimens , as in the related changchengornis , a pair of long , thin feathers proceeded from each side of the tail and expanded distally into a teardrop - shaped surface . it has been suggested that these feathers were sexually dimorphic structures and possibly indicative of males . to date , this hypothesis has not been tested statistically or corroborated by other dimorphic features .
two skeletons of the large compsognathid sinocalliopteryx gigas include intact abdominal contents . both specimens come from the jianshangou beds of the lower yixian formation ( neocomian ) , liaoning , china . the holotype of s . gigas preserves a partial dromaeosaurid leg in the abdominal cavity , here attributed to sinornithosaurus . a second , newly - discovered specimen preserves the remains of at least two individuals of the primitive avialan , confuciusornis sanctus , in addition to acid - etched bones from a possible ornithischian . although it cannot be stated whether such prey items were scavenged or actively hunted , the presence of two confuciusornis in a grossly similar state of digestion suggests they were consumed in rapid succession . given the lack of clear arboreal adaptations in sinocalliopteryx , we suggest it may have been an adept stealth hunter .
for example , the 125 - million - year - old early bird confuciusornis was found to have color variation between blacks and browns in a single feather . and dark areas in sinosauropteryx ' s tail were
absolutely packed with phaeomelanosomes ,
said benton—a finding that led the team to propose that the dinosaur ' s tail was striped with
chestnut to rufous [ reddish brown ] tones .
the pinkish halos around the forelimb of confuciusornis compare favorably to the patagia of modern birds ( fig 3 ) . the area of brighter fluorescence in the propatagia may indicate a thickened area of the skin or deformation of the soft tissues after death—the dorsal portion of the propatagia in gallus gallus is notably thicker than that of the ventral region ( fig 3c and 3d ) . the brighter region of the halo may also represent a thickened propatagial ligament found in modern birds [ 21 , 30 ] . impressions of the soft tissues of the hand of archaeopteryx have been reported [ 31 ] and compare favorably to the halos seen in confuciusornis and modern avian wings . the presence of pre - and postpatagial ligaments and tendons is difficult to determine from the laser fluorescence , however , these ligaments and tendons serve crucial functions for flight in birds , including adjustment of the camber of the wing ( prepatagial ligaments ) , control over extension of the wing [ 32 ] , and spreading of the flight feathers ( postpatagial tendons ) [ 20 ] . the likelihood of confuciusornis possessing significantly robust versions of these tendons and ligaments ( as seen in other birds , e . g . [ 21 ] ) seems high .
nudds and dyke ( reports , 14 may 2010 , p . 887 ) reported that the primary features of the early birds archaeopteryx and confuciusornis were too weak to power flight . this conclusion is not supported because the authors overestimated the mass of the subjects and understated the strength of the primary shafts in at least one example . the total biology of the birds indicates that they could achieve flapping flight .
[ 1 ] [ 2 ] c . sanctus fossil preserving long wing and tail feathers confuciusornis was about the size of a modern crow , with a wingspan of up to 0 . 7 meters ( 2 . 3 ft ) and a weight of up to 0 . 5 kilograms . [ 3 ] fossils of confuciusornis show that it had an exceptionally large humerus ( upper arm bone ) , and a characteristic hole near its shoulder - end may have reduced the bone ' s weight . the furcula or wishbone was a simple bar , like that of archaeopteryx . the sternum ( breastbone ) was relatively large and had a low keel which was raised at the back end . this bony keel may or may not have anchored a larger , cartilaginous , keel for enlarged pectoral muscles . [ 4 ] the scapula ( shoulder blades ) were fused to the coracoid bones and may have formed a solid base for the attachment of wing muscles . the orientation of the shoulder joint was sideways , instead of angled upward as in modern birds ; this means that confuciusornis was unable to lift its wings above its back . like archaeopteryx , it was thus incapable of the upstroke required for flapping flight . [ 5 ]
the humerus is characteristically confuciusornithine , having an expanded proximal end and a triangular deltopectoral crest that constitutes more than one - third of the length of the humerus [ 19 ] . an oval foramen pierces the deltopectoral crest , which is an autapomorphic feature of confuciusornis [ 19 ] , [ 22 ] . a deltopectoral foramen is absent in all other confuciusornithids including eoconfuciusornis [ 21 ] and changchengornis [ 23 ] .
based on the aforementioned shared features , the avian remains in cags - ig - t1 are unequivocally assignable to confuciusornis . confuciusornis has had a troubled taxonomic history because the description of the type species was inadequate , and as many as five species have been assigned to that genus . recent studies , however , have demonstrated that all of these specimens fall within the range of variation for the type species and are therefore synonymous with c . sanctus [ 19 ] , [ 24 ] . moreover , a second genus of confuciusornithid , jinzhouornis , and its two constituent species , has also been shown to be qualitatively and quantitatively indistinguishable from c . sanctus [ 25 ] . in light of this and the morphological considerations already discussed , the associated confuciusornithid remains in cags - ig - t1 are assigned to c . sanctus .
though it has a bony sternum , it is fairly unlikely that confuciusornis was able to power its own flight . though it had many adaptations for flight including a fused wrist and short tail , its wings were limited in their ability to lift , its wings were equipped with feathers that may have been too weak to support flapping flight , and its breast musculature was not well developed enough . however , this is still a fairly controversial position ; given the large number of specimens of this animal and the fact that they are found buried together in large groups , it has been proposed that it was a flying animal , and the large groups found are more characteristic of flying flocks than of gliding animals . still , there is no strong evidence for flight capability in confuciusornis , and only gliding capability at this time .
a particular confuciusornis known as dnhm - d1874 yielded the crucial clue . surrounded by feathers , this articulated skeleton lacked the long tail feathers seen on others . when chinsamy and colleagues looked at the microstructure of specific bones , they found medullary tissue in the humerus ( upper arm bone ) and traces in the ulna ( a lower arm bone ) , indicating that the bird had recently finished laying eggs when she perished .
de ricqlès , a . j ; padian , k ; horner , j . r ; lamm , e . - t . & myhrvold , n . ( 2003 ) : osteohistology of confuciusornis sanctus ( theropoda : aves ) . journal of vertebrate paleontology 23 ( 2 ) : 373–386 . doi : 10 . 1671 / 0272–4634 ( 2003 ) 023 [ 0373 : oocsta ] 2 . 0 . co ; 2 html abstract
exceptional preservation of soft tissues in jehol vertebrates . ( a ) tail feathers of a sinosauropteryx ( courtesy of x . wang ) , ( b ) flight feather of a confuciusornis ( courtesy of x . zheng ) , ( c ) skin of a lizard liushusaurus ( courtesy of y . wang ) , and ( d ) eyes , muscles , and gonads of a lamprey mesomyzon ( courtesy of j . zhang ) .
there is evidence that the propatagium of birds contributes disproportionately to lift production between the wrist and the elbow [ 11 ] , and the primary feathers generate lift from the wrist outwards . the extensive and robust propatagium in confuciusornis would have generated a large amount of lift . furthermore , a thick and deep postpatagium suggests strong tendons running parallel to the edge of the postpatagium , anchoring the flight feather calami in place [ 20 ] . the deeper and thicker the postpatagium , the stronger the attachment of the flight feathers , and the less likely the feathers are to buckle and twist . all of the above factors , along with the length and shape of the primary and secondary feathers , the robustness of the primary rachises , combined with the presence of a small but relatively extensive keel [ 36 ] , strongly suggest that confuciusornis did have the capability for powered flight .
the wider , broader wing in confuciusornis confirms a flight style different than previously suggested ( see [ 6 ] ) ( fig 6 ) . wide , broad wings are found in 1 ) birds that live in a densely vegetated area requiring high maneuverability and 2 ) broad - winged soaring birds such as hawks and vultures . although there is minor separation between the tips of the primaries in ivpp v13156 , the presence of slotted wing tips is difficult to determine . slotted wing tips are typical of broad - winged soaring birds , which aid in reducing drag during soaring [ 24 , 25 ] and may improve stability while gliding [ 26 ] . reconstructions of a heavily forested environment surrounding the lake ( s ) of the lower cretaceous jehol group ( e . g . , [ 27 , 28 ] ) implies confuciusornis required more maneuverability and stability than speed in flight . the aspect ratio of confuciusornis is between 6 . 4 ( including tertial feathers ) and 7 . 7 ( excluding tertial feathers ) , which indicates that it was not a dynamic soarer ( e . g . , seabirds ) , long - distance migrant ( e . g . , shorebirds ) , or a long - duration fast flyer ( e . g . , swifts ) , which have higher aspect ratios [ 29 ] .
paul and zheng et al . challenge our conclusions regarding the flight of confuciusornis and archaeopteryx , which derive from our method of assessing flight ability from estimated feather strength . they suggest that our mass and rachis data for these fossil birds are incorrect . neither comment , however , invalidates our method nor alters conclusions of poor flight ability based upon our original data . we encourage researchers to use our method before critiquing our conclusions regarding early bird flight .


the butterfly rays are the rays forming the genus gymnura and the family gymnuridae .

they are found in warm oceans worldwide , and occasionally in estuaries .

the body of butterfly rays is flattened and surrounded by an extremely broad disc formed by the pectoral fins , which merge in front of the head .

they have a very short , thread-like , tail .

they are up to 4 m ( 13 ft ) in width .

mceachran et al. place the butterfly rays in the subfamily gymnurinae of the family dasyatidae , but this article follows fishbase and itis in treating them as a family .

butterfly ray

backwater butterfly ray - gymnura natalensis the backwater butterfly ray is also known as the diamond ray . source : arkive intended audience : general reading level : middle school teacher section : yes
spiny butterfly ray - gymnura altavela the spiny butterfly ray feeds on fish , squid , and crustaceans . source : arkive intended audience : general reading level : middle school teacher section : yes
in the western atlantic ocean , the spiny butterfly ray is found from southern new england to brazil .
the juvenile spiny butterfly ray has paler skin , which darkens to brown as it matures ( 4 ) .
. 2007 ) , and predation pressure on the california butterfly ray may therefore be lower than historic levels .
the spiny butterfly ray may be infected by parasites , most notably by the tapeworm anthobothrium altavelae ( 7 ) .
the spiny butterfly ray reproduces annually . this species is ovoviviparous , and the gestation period lasts between four and nine months . the litter size of the spiny butterfly ray is between two and eight , depending on location ( 1 ) .
. 2007 ) . gymnurd rays are also among the most common species taken in the gulf of california artisanal elasmobranch fishery . however , the relative contribution of the california butterfly ray to these landings cannot be determined because of a lack of species - specific fisheries data and the historic taxonomic uncertainty between the california butterfly ray and the longsnout butterfly ray ( bizzarro
the california butterfly ray has been reported from point conception , southern california ( united states ) to point lobos de afuera , peru ( beebe and teevan 1941 , miller and lea 1972 ) . however , recent evidence suggests that the longsnout butterfly ray replaces the california butterfly ray in tropical regions , implying a largely warm - temperate distribution for the california butterfly ray ( smith et al . 2009a ) . the confirmed range of the california butterfly ray is therefore much more restricted that previously specified , and extends continuously from point conception to central sonora , mexico ( smith et al . 2009a ) . only the longsnout butterfly ray has been observed during recent collection efforts off mazatlan , sinaloa ( mexico ) and all tropically - derived specimens of the california butterfly ray examined among regional museum collections are actually misidentified the longsnout butterfly ray ( j . j . bizzarro and w . d . smith pers . obs . ) . these findings suggest that the transition zone for the california butterfly ray and the longsnout butterfly ray occurs between central sonora and northern sinaloa in the eastern gulf of california . further investigation is necessary to confirm these conclusions and to reliably establish the southern extent of this species’ range .
smooth butterfly ray - gymnura micrura the smooth butterfly ray is found in the western and eastern atlantic ocean and in the gulf of mexico . source : florida museum of natural history intended audience : students reading level : high school teacher section : yes
the spiny butterfly ray is less threatened in us waters , where fishing levels are are lower . however , in the mediterranean sea , there is much higher demand for the spiny butterfly ray’s meat . it is now so rare in the mediterranean , the spiny butterfly ray has been absent from the mediterranean international trawl survey ( medits ) records since they began in 1994 ( 1 ) .
despite the rapidly declining numbers of the spiny butterfly ray , there are currently no specific conservation management programmes in place , and intensive trawling continues throughout this species’ range . however , the spiny butterfly ray is fully protected in the banc d ' arguin national park in mauritania . monitoring of spiny butterfly ray populations and protection in areas where it is heavily fished are needed ( 1 ) .
the spiny butterfly ray can be found over sandy and muddy sea floors in shallow coastal waters , normally around depths of 50 to 55 metres . its patchy distribution means that the spiny butterfly ray is abundant in some areas , and scarcely found in others ( 1 ) .
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, in particular , appears to specialize in eating stingrays . it uses its hammer head to knock a ray to the bottom , and then pins the ray , once again with its head , pivoting around to bite the ray’s disc until the ray succumbs and can be eaten . in addition to their defensive venomous sting , many rays have drab coloring that matches the sand or mud bottom . several species of butterfly ray can quickly change color to blend in with their background .
. ( 2009a ) to conclude that the pacific and gulf of california the california butterfly ray populations should be considered as separate stocks for conservation and management purposes .
, for example , the young ray’s net weight increases by 4900 % from egg to birth , and are between 15 - 22 cm when they are born . development in the uterus usually takes about two to four months . one species of butterfly ray ,
. 2009a ) . both morphometric and molecular techniques confirmed the validity of the longsnout butterfly ray as a distinct species . furthermore , the phylogeny and genetic distances determined by smith
little is known about the biology of the spiny butterfly ray . however , it is known that this species’ sharp pectoral fins are used to stun prey such as crustaceans , molluscs , plankton and small fishes . the spiny butterfly ray also may predate small sharks and squids , and may in turn be preyed upon by larger sharks ( 7 ) .
the smooth butterfly ray prefers neritic waters of the continental shelf and is usually found on soft bottoms . this species is known to enter brackish estuaries or hyper - saline lagoons .
along the coast of west africa , large mesh bottom gillnets are used to target the spiny butterfly ray in huge numbers . even in protected marine areas , the average size of caught spiny butterfly rays has reduced as larger adults from the population are removed ( 1 ) .
) occurs in nearshore and inshore waters of the eastern north pacific , from southern california to the central or southern gulf of california , and appears to be abundant throughout its range . probably as a consequence of its apparent abundance , the california butterfly ray is one of the primary species landed in artisanal elasmobranch fisheries of northwestern mexico . catch records of the california butterfly ray have been historically lumped into generalized categories ; therefore , population trends cannot be determined . this issue is further complicated by the historic taxonomic confusion between this species and the longsnout butterfly ray (
henningsen , a . ( 1998 ) captive husbandry and bioenergetics of the spiny butterfly ray , gymnura altavela ( linnaeus ) . zoo biology , 15 ( 2 ) : 135 - 142 .
common english names for this species include : lesser butterfly ray , diamond skate , butterfly ray , short - tailed lesser butterfly ray , and skeete . other names include arraia ( portuguese ) , gladde vlinderrog ( dutch ) , korthalet sommerfuglerokke ( danish ) , krídloun hladký ( czech ) , motýlovec hladkýpari ( czech ) , gampret ( malay ) , perhosrausku ( finnish ) , raie - papillon glabre ( french ) , raya guayanesa ( spanish ) , raya mariposa menor ( spanish ) , togenashi - tsubakuro - ei ( japanese ) , and uge - borboleta ( portuguese ) .
severe declines in the landings of large , predatory sharks and upper trophic level teleosts have been noted in mexican waters and predation pressure on the california butterfly ray may therefore be lower than historic levels .
the upperparts of the spiny butterfly ray are usually brown to grey , sometimes with reddish - brown shading at the margins of the ‘wings’ . small dark or light spots and blotches may produce a marbling effect across the back . the colouration of the spiny butterfly ray , along with its wide , flat , disc - shaped body enable it to effectively camouflage itself in sand beds ( 5 ) ( 6 ) . the underside is generally white , brown or rosy - coloured . the spiny butterfly ray has a blunt snout , and the jaws contain many rows of teeth ( 4 ) ( 5 ) .
this is a small ray that does not possess a spine . therefore it represents little danger to humans .
intense fishing in the southwest atlantic , particularly around the coast of brazil has led to declines in spiny butterfly ray populations . in 23 years , the percentage of trawl catches has reduced by an estimated 99 percent ( 1 ) .
this ray can be distinguished from the spiny butterfly ray ( g . altavela ) by the absence of both a tentacle like structure protruding from the inner posterior margin of the spiracle and a caudal fin spine . the absence of a tail spine and the presence of a keel on the upper surface of the tail separates g . micrura from g . hirundo .
bloch and schneider first described the smooth butterfly ray in 1801 . the genus gymnura of the currently accepted scientific name is derived from the greek word gymnos meaning naked . synonyms for gymnura micrura include pteroplatea micrura , raja micrura and gymnura micura .
the dorsal surface of this ray varies greatly in color , either gray , brown , or light green . photo © christina conrath
the spiny butterfly ray ( gymnura altavela ) gets its name from its wide , characteristically wing - like pectoral fins , and its short , sharp tail , which has serrated spines on both sides , used to stun prey ( 3 ) ( 4 ) .
. 1960 ) to depths of at least 94 m ( amezcua - linares 1996 ) . warm - temperate in distribution , the california butterfly ray is associated with sandy bays and beaches as well as silty or muddy tidal channels and estuaries ( beltrán - félix
reportedly sometimes marketed for its meat ( last and stevens 2009 ) although it is of very little commercial interest . the major prawn trawl fisheries in which it is caught ( see threats section ) are not permitted to retain elasmobranchs , so the australian butterfly ray is primarily discarded .
the california butterfly ray also has a moderately high fecundity ( up to 16 pups / litter ) compared with other elasmobranchs , including congeners ; may reproduce throughout the year ; and appears to grow rapidly . in addition , although it has not yet been enforced , the recent national management plan for sharks and rays provides for a cessation of fishing activities in important nursery regions , including bahía almejas , during the peak summer breeding season . based on this information and the apparent abundance of the california butterfly ray throughout its range , this species is assessed as least concern .
there are no conservation actions in place for the california butterfly ray in united states ( i . e . , california ) waters , but there are also no major threats . nearshore trawl and gillnet fisheries that may negatively impact this species have been curtailed or severely reduced in california as a result of bycatch issues and substantial population declines in traditionally targeted teleost groundfishes . there also are no conservation actions specific to the california butterfly ray in mexico . however , details of the recent national management plan for sharks and rays provides for the cessation of fishing activities in important nursery regions , including bahía almejas , during the peak summer breeding season . this management strategy could prove to be highly effective in maintaining sustainable populations of the california butterfly ray and other coastal sharks and rays . however , efforts to implement and enforce seasonal fishing bans have been largely unsuccessful .
jacobsen , i . p & bennett , m . b . 2009 . a taxonomic review of the australian butterfly ray gymnura australis ( ramsay & ogilby , 1886 ) and other members of the family gymnuridae ( order rajiformes ) from the indo - west pacific . zootaxa 2228 : 1 - 28 .
flesh of the california butterfly ray is typically dried and sold locally for human consumption in the northern mexican pacific . it is also caught occasionally by commercial and recreational fishers in southern california , but is of no commercial importance in this region . there is no national or international trade of this species .
no quantitative information is available on the size or trends of the california butterfly ray populations but this species appears to be common in nearshore and inshore waters of the pacific coast of the baja peninsula and in the northern gulf of california . it is often landed in mixed species demersal fisheries in both regions , and is one of the most common species taken in the bahía almejas ( baja california sur ) ray fishery ( villavicencio - garayzar 1995 , bizzarro 2005 , bizzarro
the australian butterfly ray has two distinct morphological variants which are principally separated by the presence or absence of a small dorsal fin ( jacobsen and bennett 2009 ) . dorsal surface colouration can vary in this species from a uniform light green to a dark olive or grey - green and is highly dependent on the surrounding environment .
the spiny butterfly ray has a very patchy distribution in the coastal tropical and temperate waters of the atlantic ocean , the mediterranean and the black sea . this species can be found in areas on both sides of the atlantic , in the western coastal waters of north and south america , and in eastern coastal waters from portugal to angola ( 1 ) .
butterfly rays feed upon crabs , shrimps , various invertebrates , fishes , small crustaceans , and mollusks . they generally seek prey near the bottom of warm waters over sandy stretches .
) is migratory , moving into temperate waters during the warm season . butterfly rays forage for food over the sandy bottoms on which they live . some butterfly rays are equipped with a venomous tail spine that they use in defense . due to their short tails and smaller spines , however , their stings are generally less fierce than those of their stingray relatives .
as their name indicates , butterfly rays have extremely wide pectoral fins that resemble butterfly wings . these fins create a disc that is more than 1 . 5 times as broad as it is long and extends forward to include the head , ending in a blunt , angular , short snout . the snout is rounder and blunter on females than on males , at least in the case of
although butterfly rays do not have any particular commercial importance , cartilaginous fishes in general are important to humans in a number of ways . australian aborigines have eaten rays for centuries . they determine whether a seasonal catch is ready to eat by checking a ray’s liver ; if it is oily and pinkish white , the ray is suitable for eating . rays that have two spines , however , are considered inedible . australian aborigines , malayans , tribes in south and central america , and west africa , and peoples of the indo - pacific have used ray spines for spear tips , daggers , or whips . rays are considered food fish in australia , europe , and parts of asia , and in some places are among the most highly priced fishes . in australia , cuts from one species of butterfly ray are sometimes sold as skate flesh . like shark fins , fins of some rays are harvested in asia for soup and as an aphrodisiac . cartilaginous fishes are used for medical purposes as well . chondroiten , used as skin replacement for burn victims , is derived from the fishes’ cartilage . other extracts from cartilage help suppress tumors and may assist cancer treatment . some large rays are a popular part of public aquarium exhibits .
butterfly rays have little negative impact on humans . they are not known to destroy shellfish beds , and their spines , when present , are much less dangerous than those of their long - tailed relatives (
the smooth butterfly ray is found in the western and eastern atlantic ocean and in the gulf of mexico . in the western atlantic it occurs from maryland to brazil . it occurs in the gulf of mexico and northern south america to brazil . it also occurs in the eastern atlantic off the coasts of senegal , gambia , sierra leone , cameroon and democratic republic of the congo ( to the mouth of congo river ) .
threats are comparatively minor in the united states , where this species is typically only abundant during warm water periods . winter residents appear largely restricted to individuals occurring in association with areas of elevated temperature due to discharge from power plants . u . s . gillnet and trawl fisheries that would typically catch the california butterfly ray have been largely curtailed or moved to deeper waters beyond its depth range , and recreational landings are trivial .
justification : the tentacled butterfly ray ( gymnura tentaculata ) is known from very few specimens . the species is recorded from india and papua new guinea , but records from papua new guinea may be misidentifications of australian butterflly ray ( g . australis ) and probably require further clarification . virtually nothing is known of this species at present and therefore it cannot be assessed beyond data deficient . however , fishing pressure is intense throughout its range and rapid declines have been observed in similar species where they are heavily fished ( e . g . , gymnura altavela off brazil ) . this species may also prove to be threatened and re - assessment is recommended in the near term .
. 2007 ) . these rays are most often targeted with bottom set gillnets but beach seines are also used in some locations . the mexican fisheries that exploit the california butterfly ray are largely unregulated . a national elasmobranch management plan was recently enacted in mexico , including a moratorium on fishing in important nursery habitats during summer months , when many elasmobranchs utilize nearshore regions for reproductive purposes . however , most regulations , including the seasonal fishing ban , have not been enforced .
this is a broad , diamond - shaped ray with a very short tail lacking a dorsal spine and a protruding snout . the front edges of the disk are concave . the tail has low dorsal and ventral finfolds and three to four dark crossbars .
this diamond - shaped ray is much wider than it is long , usually 3 to 4 feet wide , and its short tail lacks the ray ' s usual spine . it can vary from light brown to gray to greenish , with lighter or darker spots , and can manipulate its shading to blend better into its background . it is tolerant of a variety of salt content , from brackish river mouths to highly saline lagoons , as long as there is a muddy or sandy bottom to hunt small fish and invertebrates .
. 1986 , villavicencio - garayzar 1993 ) but early life stages seem to utilize these areas for nursery functions ( bizzarro 2005 ) . although this general reproductive pattern seems valid , gravid females with near - term embryos also have been observed during winter months in bahía almejas , and it is possible that there is either a smaller reproductive peak at this time , or else that the population is capable of reproducing throughout the year ( bizzarro 2005 ) . since pupping , mating , and nursery functions occur in inshore regions , these habitats are essential to the propagation of the species . however , artisanal fisheries in mexico target reproductive aggregations of the california butterfly ray and other ray species on their breeding grounds , which may have considerable negative implications for the long - term sustainability of exploited populations ( bizzarro
gymnuridae is a marine family , but are occasionally found in estuaries and river mouths as well . butterfly rays are benthic ( bottom - dwellers ) , most commonly found on the upper continental shelf . they prefer stretches of open sand and frequent shallow beaches and bays .
coloration the dorsal surface of this ray is gray , brown or light green , dotted and vermiculated with paler and darker spots . the tail has three to four dark crossbars . the ventral surface is white . this species has some ability to adapt it ' s shade to that of the bottom .
identification disc broad , much wider than long ( ' butterfly shaped ' ) . coloration brownish , gray or green with many small dark spots / blotches dorsally and white ventrally . snout protruding . tail short with low dorsal and ventral fin folds and three to four dark crossbars . no venomous spine on tail .
there are 14 species in this family . butterfly rays have broad , triangular pectoral fins ; short , whip - like tails ; and no anal fin , dorsal fin , or caudal fin . some species have a spine on their tails . they are found in the atlantic , indian , and pacific oceans .
population size and structure of the australian butterfly ray is unknown . it is common along the northern and northeastern extent of its australian distribution but is not considered an abundant species . the species is more abundant at higher latitudes and is frequently encountered in the gulf of carpentaria . regionally , this species may be more prominent in inshore bays such as moreton bay in southeast queensland ( 27°11′s , 152°15′e ) . the species was originally described from broken bay , new south wales ( 33°33′s , 149°13′e ) . however , there has been very few reports of the australian butterfly ray occurring south of moreton bay ( queensland ) since the original description . this suggests that the species is relatively rare in new south wales and that the abundance of this species in this region of australia tends to be lower . this inference is supported by the fact that a wide and varied range of sampling surveys have been undertaken in this region over recent years without encountering this species . this includes in habitats and fisheries where it would be expected to occur or be encountered ( e . g . , liggins et al . 1996 , grey et al . 2001 , 2003 , k . graham , pers . comm . , 2015 ) . information on the abundance of this species in northwestern australia and new guinea is limited .
the california butterfly ray is susceptible to a variety of fishing gears and is commonly taken in inshore and nearshore fisheries . in mexico it is caught incidentally in shrimp trawl fisheries , and directly or indirectly caught with longlines , beach seines , and gillnets . whether retained or discarded , mortality is inferred to be high in these fisheries , especially in the gulf of california shrimp trawl fishery ( márquez - farías 2002 ) . furthermore , it is subjected to directed , mixed - species artisanal elasmobranch fisheries in mexico where it is a primary component of landings off the southern pacific coast of the baja california peninsula and in the northern gulf of california ( villavicenico - garayzar 1995 , bizzarro 2005 , bizzarro
previous studies of the family gymnuridae have divided it into two genera based on the presence or absence of a dorsal fin ; aetoplatea with a dorsal fin and gymnura without ( murdy et al . 1997 , compagno and last 1999 , vossoughi and vosoughi 1999 , oshigou et al . 2004 , yano et al . 2005 ) . a recent taxonomic review of the australian butterfly ray gymnura australis ( ramsay and ogilby 1886 ) , supports the amalgamation of all species into a single genus ; gymnura ( jacobsen 2007 ) . jacobsen ( 2007 ) found that dorsal fin development in g . australis is variable and inconsistent with the two genus hypothesis , thus suggesting that aeteoplata should be designated as a junior synonym .
, has a long tentacle near the back edge of the spiracles . like all rays , butterfly rays have ventral gill openings . these form five small pairs and the internal gill arches do not have filter plates . their mouths are relatively large and located under the end of the snout . since their mouths are directed downward and often placed against the sand , bottom - living rays use their spiracles rather than their mouths for water intake , and , if the gills are covered with sand , the spiracles are also used for expelling water . butterfly rays have small , cuspidate teeth that do not form the crushing plates found in many other rays . their dorsal fins , if present , are small . they lack anal fins , and rather than a caudal fin they may have low dorsal and ventral ridges on the tail . the slender tail is much shorter than the disc . some butterfly rays have a stinging spine behind the pelvic fins . these fish range in size from less than 0 . 5 m long to over 2 m long .
broad , diamond - shaped ray with a very short tail lacking a dorsal spine ( ref . 26938 ) . snout protruding . front edges of disk concave . tail with low dorsal and ventral finfolds and 3 - 4 dark crossbars ( ref . 7251 ) . upper surface gray , brown , light green or purple with round spots . lower surface white ( ref . 6902 ) .
the australian butterfly ray is found in warm - temperate and tropical waters of australia and the southern coast of new guinea ( papua new guinea and indonesian west papua ) in the eastern indian and western pacific oceans ( jacobsen and bennett 2009 , last and stevens 2009 ) . the australian distribution extends from shark bay ( western australia ; 25°47′s , 113°42′e ) across northern australia to broken bay ( new south wales ; 33°33′s , 151°18′e ) and includes the timor sea , arafura sea and the torres strait ( russell and houston 1989 , jacobsen and bennett 2009 , last and stevens 2009 ) . previous reports of this species occurring in eastern indonesia ( outside of west papua ) are more than likely misidentified specimens from morphologically similar species ( w . white , pers . obs . ) .
the australian butterfly ray is a demersal species that inhabits inshore , intertidal environments to depths of at least 60 m ( last and stevens 2009 ) . the species prefers open water environments that lack structure and have sandy , muddy or silty substrates . sexual dimorphism occurs in this species with females attaining a larger size than males . females reach a disc width ( dw ) of at least 94 cm ; males reach 57 . 5 cm dw ( jacobsen et . al . 2009 ) . the onset of sexual maturity occurs from 44 - 46 cm dw for females and 38 - 42 cm dw for males . this species is viviparous with developing embryos relying on both yolk and placental analogues . uterine fecundity for this species is 1 - 6 embryos with size at birth estimated to be between 22 and 25 cm dw ( jacobsen et al . 2009 ) . preliminary estimates suggest the species has an annual reproductive cycle , producing a single litter every 12 months ( i . jacobsen , pers . obs . ) , although further information is required on this aspect of its biology .
only a few species of elasmobranch ( subclass including all sharks and rays ) fishes have been observed during courtship and mating . however , butterfly rays have a system that involves internal fertilization , so it can logically be inferred that mating communication between male and female must happen to an extent that allows the male to insert at least one of his two claspers ( male reproductive organs that are modifications of the pelvic fins ) into the female’s cloaca to deposit sperm . elasmobranch fishes have relatively complex endocrine ( hormonal ) systems ; based on knowledge of other vertebrates with similar systems , it is likely that females signal to males through chemical or behavioral cues to indicate when their hormonal state is appropriate for mating .
. 1986 , villavicencio - garayzar 1993 ) . along the pacific coast of mexico’s baja peninsula , the abundance of this ray increases notably in shallow embayments during april and may ( beltrán - félix et al . 1986 , villavicencio - garayzar 1993 ) . in bahía almejas , gravid females typically immigrate during april followed by adult males in may ( villavicencio - garayzar 1993 , davila - ortiz , 2002 ) . courtship and fertilization are thought to occur from may through august in this region , with near - term embryos observed from april through september ( davila - ortiz 2002 , j . j . bizzarro and w . d . smith pers . obs . ) . by late august , mature individuals are less common in shallow embayments ( beltrán - félix
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compagno , leonard j . v . / hamlett , william c . , ed .
nelson , joseph s . , edwin j . crossman , h . espinosa - pérez , l . t . findley , c . r . gilbert , et al . , eds .
full author list : nelson , joseph s . , edwin j . crossman , héctor espinosa - pérez , lloyd t . findley , carter r . gilbert , robert n . lea , and james d . williams
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 .
this species is caught in minor commercial fisheries and is occasionally used for food in french guiana and possibly in other tropical localities . the wings may be taken for bait in crab or other fisheries .
the iucn is a global union of states , governmental agencies , and non - governmental organizations in a partnership that assesses the conservation status of species .
dentition the upper jaw generally has 60 to 120 teeth and lower jaw generally has 52 to 106 teeth , with each tooth having one short sharp conical cusp on a somewhat swollen base . eight to nine rows of teeth function simultaneously . the upper dental plate occupies 70 to 75 % of the width of the jaw and the lower dental plate occupies 60 to 65 % of the width of the jaw .
the maximum disc width of the species is reported to be 3 to 4 feet ( 0 . 9 to 1 . 2 m ) . females of the northwestern atlantic population pup when 25 inches ( 65 cm ) wide , and probably at smaller lengths .
food habits feeds on fish and invertebrates , more specifically : bony fish , benthic copepods , crabs , shrimps , prawns , and bivalves .
reproduction exhibits ovoviparity ( aplacental viviparity ) , with embryos feeding initially on yolk , then receiving additional nourishment from the mother by indirect absorption of uterine fluid enriched with mucus , fat or protein through specialized structures .
classified as vulnerable ( vu ) on the iucn red list ( 1 ) .
this information is awaiting authentication by a species expert , and will be updated as soon as possible . if you are able to help please contact : arkive @ urltoken
filiz , h and blige , g . ( 2004 ) length - weight relationships of 24 fish species from the north aegean sea , turkey . journal of applied ichthyology , 20 ( 5 ) : 431 - 432 .
campbell , a . and dawes , j . ( 2004 ) encyclopedia of underwater life . oxford university press , oxford .
mceachran , j . d . and fechhelm , j . d . ( 1998 ) fishes of the gulf of mexico : myxiniformes to gasterosteiformes . university of texas press , austin , usa .
still pictures ltd . 1 glen cottages sandy lane abbots leigh bristol bs8 3se united kingdom tel : + 44 ( 0 ) 1275 375 520 fax : + 44 ( 0 ) 705 061 3938 research @ urltoken http : / / www . urltoken
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habitat and behavior demersal species found in coastal waters and usually found on soft mud or sandy substrates . may enter estuaries or bays .
fwc facts : a shrimp escapes predators by quickly pulling its abdomen in toward its carapace ( body ) . this motion shoots it through the water backward .
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thank you for taking the time to provide feedback on the iucn red list of threatened species website , we are grateful for your input .
the relationship between the subpopulation occurring in french polynesia and the rest of the species ' range may require critical examination .
found in shallow , inshore waters of the red sea , somalia and oman and from pakistan through the eastern indian ocean and north from indonesia to southern japan in the western pacific , as well as an isolated population in french polynesia ( compagno and last 1999 ) . may occur between oman and pakistan as well , but not reported .
no other information on the abundance , population size , or degree of fragmentation of this species is known from its range .
considerable parts of this species ' range are subject to intensive inshore fisheries ( for example indonesia and thailand both with high pressure on their marine resources , which is only likely to increase in the future ) . directed artisanal and commercial trawl and bottomset gillnet fisheries have been historically reported in palk bay and the gulf of mannar , india , but no recent published literature is available to document current fishing trends ( james 1966 ) . based on historic information , g . poecilura occurred in landings year - round , with a peak of abundance between january and may . the dominant size range in this fishery ranged from 35 to 70 cm dw ( james 1966 ) . it is also currently targeted in thailand and indonesia for human consumption by artisanal fisheries and is also caught as bycatch in other artisanal and commercial fisheries throughout its range ( compagno and last 1999 , w . white unpubl . data ) . although no specific information is available , habitat loss and degradation may also be affecting this species given its inshore coastal occurrence .
there are no conservation measures in place for this species throughout its range . direct and indirect catches in artisanal and commercial fisheries throughout its distribution need to be documented . the development and implementation of management plans ( national and / or regional e . g . under the fao international plan of action for the conservation and management of sharks : ipoa - sharks ) are required to facilitate the conservation and sustainable management of all chondrichthyan species in the region . see anon . ( 2004 ) for an update of progress made by nations in the range of g . poecilura .
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( allen and robertson , 1994 ; böhlke and chaplin , 1968 ; compagno , 1999 ; hamlett and koob , 1999 ; helfman , et al . , 1997 ; last and stevens , 1994 ; moyle and cech , 2000 ; nelson , 1994 ; wheeler , 1985 ; wourms and demski , 1993 )
members of the family gymnuridae can be found worldwide in tropical and warm temperate seas . their range in the atlantic includes the black sea , and they are widely distributed in the pacific and indian oceans .
. the disc is brown , grayish , purplish or greenish in color , sometimes with pale and dark spots , and it may be naked or covered with small denticles . the head is even with the disc rather than elevated , giving the fish a very flat appearance from the side view . the eyes are located on the sides of the top of the head , with the spiracles ( respiratory openings ) close behind the eyes . at least one species ,
members of the family gymnuridae , like other rays and their shark relatives , employ a reproductive strategy that involves putting a great investment of energy into relatively few young over a lifetime . since few young are produced , it is important that they survive , and to this end rays are born at a large size , able to feed and fend for themselves much like an adult . rays develop from egg to juvenile inside the mother’s uterus , sometimes to almost half their adult size . in this system , called aplacental uterine viviparity , developing embryos receive most of their nutriment from a milky , organically rich substance secreted by the mother’s uterine lining . an embryo absorbs this substance , called histotroph , by ingestion , or through its skin or other specialized structures . researchers have found that in some stingrays , the stomach and spiral intestine are among the first organs to develop and function , so that the embryo can digest the uterine “milk . ” rays’ eggs are small and insufficient to support the embryos until they are born , although the first stage of development does happen inside tertiary egg envelopes that enclose each egg along with egg jelly . the embryo eventually absorbs the yolk sac and stalk and the histotroph provides it with nutrition . embryos are so well nourished in the uterus that in
, is born with an almost triangular shape , but develops much wider pectoral fins as it grows , and in adults the disc is more than twice as broad as it is long .
( böhlke and chaplin , 1968 ; hamlett and koob , 1999 ; helfman , et al . , 1997 ; last and stevens , 1994 ; moyle and cech , 2000 ; wheeler , 1985 ; wourms , 1993 )
( allen , 1996 ; böhlke and chaplin , 1968 ; hamlett and koob , 1999 ; helfman , et al . , 1997 ; last and stevens , 1994 ; moyle and cech , 2000 ; wheeler , 1985 ; wourms , 1993 )
no reported evidence of parental care in gymnuridae was found . after such extended nurturing inside their mothers’ bodies , young rays come into the sea quite able to feed and fend for themselves ( see development and reproduction ) .
little specific information regarding lifespans in gymnuridae was found , but in general rays , like their relatives the sharks , grow and mature slowly and are long - lived . some researchers estimate that the largest sharks and rays may not reach maturity until 20 to 30 years of age , and that they may live to maximum ages of 70 to 100 years or more . the family gymnuridae does not include the largest rays and may not reach such extremes of longevity .
( allen , 1996 ; bleckmann and hofmann , 1999 ; helfman , et al . , 1997 )
although rays can grow very large , they are still preyed upon by other large fishes , especially sharks . stingray spines have been found embedded in the mouths of many sharks . the great hammerhead
stingrays are nearly cosmopolitan in tropical and warm temperate seas , and therefore are a consistent predator on populations of mollusks , crustaceans , worms , and fishes . they , in turn , provide food for sharks and other large fishes .
( helfman , et al . , 1997 ; last and stevens , 1994 )
the body of water between africa , europe , the southern ocean ( above 60 degrees south latitude ) , and the western hemisphere . it is the second largest ocean in the world after the pacific ocean .
living in australia , new zealand , tasmania , new guinea and associated islands .
living in sub - saharan africa ( south of 30 degrees north ) and madagascar .
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 .
living in the southern part of the new world . in other words , central and south america .
body of water between the southern ocean ( above 60 degrees south latitude ) , australia , asia , and the western hemisphere . this is the world ' s largest ocean , covering about 28 % of the world ' s surface .
living in the northern part of the old world . in otherwords , europe and asia and northern africa .
referring to an animal that lives on or near the bottom of a body of water . also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones . bottom habitats in the very deepest oceans ( below 9000 m ) are sometimes referred to as the abyssal zone . see also oceanic vent .
having body symmetry such that the animal can be divided in one plane into two mirror - image halves . animals with bilateral symmetry have dorsal and ventral sides , as well as anterior and posterior ends . synapomorphy of the bilateria .
having markings , coloration , shapes , or other features that cause an animal to be camouflaged in its natural environment ; being difficult to see or otherwise detect .
an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity .
the area of shoreline influenced mainly by the tides , between the highest and lowest reaches of the tide . an aquatic habitat .
offspring are produced in more than one group ( litters , clutches , etc . ) and across multiple seasons ( or other periods hospitable to reproduction ) . iteroparous animals must , by definition , survive over multiple seasons ( or periodic condition changes ) .
( as perception channel keyword ) . this animal has a special ability to detect the earth ' s magnetic fields .
the area in which the animal is naturally found , the region in which it is endemic .
islands that are not part of continental shelf areas , they are not , and have never been , connected to a continental land mass , most typically these are volcanic islands .
found in the oriental region of the world . in other words , india and southeast asia .
that region of the earth between 23 . 5 degrees north and 60 degrees north ( between the tropic of cancer and the arctic circle ) and between 23 . 5 degrees south and 60 degrees south ( between the tropic of capricorn and the antarctic circle ) .
the region of the earth that surrounds the equator , from 23 . 5 degrees north to 23 . 5 degrees south .
an animal which has an organ capable of injecting a poisonous substance into a wound ( for example , scorpions , jellyfish , and rattlesnakes ) .
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female .
bleckmann , h . , m . hofmann . 1999 . special senses . pp . 300 - 328 in w hamlett , ed .
. wynnewood , pa : published for the academy of natural sciences of philadelphia by livingston .
compagno , l . 1999 . systematics and body form . pp . 1 - 42 in w hamlett , ed .
hamlett , w . 1999 . male reproductive system . pp . 444 - 470 in w hamlett , ed .
hamlett , w . , t . koob . 1999 . female reproductive system . pp . 398 - 443 in w hamlett , ed .
liem , k . , a . summers . 1999 . muscular system : gross anatomy and functional morphology of muscles . pp . 93 - 114 in w hamlett , ed .
the world conservation union , 2003 .
iucn 2002
( on - line ) . 2002 iucn red list of threatened species . accessed november 21 , 2003 at urltoken .
wourms , j . 1993 . maximization of evolutionary trends for placental viviparity in the spadenose shark , scoliodon laticaudus . pp . 269 - 293 in l demski , j wourms , eds .
wourms , j . , l . demski . 1993 . the reproduction and development of sharks , skates , rays , and ratfishes : introduction , history , overview , and future prospects . pp . 7 - 21 in l demski , j wourms , eds .
to cite this page : 2004 .
gymnuridae
( on - line ) , animal diversity web . accessed july 09 , 2018 at urltoken
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 .
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status taken from icun redlist . if no status is listed , there is not enough data to establish status , or there is no status data for the species .
greek , gymnos = naked + greek , oura = tail ( ref . 45335 )
marine ; brackish ; demersal ; depth range ? - 55 m ( ref . 27549 ) . deep - water
southwestern atlantic : venezuela , including trinidad and tobago , to brazil ( rio de janeiro ) . nominal records from off sri lanka , india , malaysia , singapore , viet nam , borneo and sumatra in indonesia , and the philippines need to be verified if indeed it is the same species that occurs in the atlantic ( ref . 9918 ) .
maturity : l m ? , range 34 - 50 cm max length : 137 cm wd male / unsexed ; ( ref . 4439 ) ; common length : 90 . 0 cm wd male / unsexed ; ( ref . 5217 )
prefers neritic waters of the continental shelf and usually found on soft bottoms . may enter brackish estuaries or hyper - saline lagoons ( ref . 5217 ) . feeds on fish and shrimps ( ref . 28587 ) ; other crustaceans and clams ( ref . 27549 ) . ovoviviparous ( ref . 50449 ) . generally marketed salted ( ref . 5217 ) .
exhibit ovoviparity ( aplacental viviparity ) , with embryos feeding initially on yolk , then receiving additional nourishment from the mother by indirect absorption of uterine fluid enriched with mucus , fat or protein through specialised structures ( ref . 50449 ) . distinct pairing with embrace ( ref . 205 ) .
mceachran , j . d . and b . séret , 1990 . gymnuridae . p . 64 - 66 . in j . c . quero , j . c . hureau , c . karrer , a . post and l . saldanha ( eds . ) check - list of the fishes of the eastern tropical atlantic ( clofeta ) . jnict , lisbon ; sei , paris ; and unesco , paris . vol . 1 . ( ref . 4439 )