gogoselachus ( " shark from the gogo formation " ) is an extinct genus of cartilaginous fish known from the late devonian of australia .

it is one of the earliest well-preserved devonian chondrichthyans ( 20 million years older than cladoselache ) , as much more of the fish than just teeth and scales were preserved .

this rare preservation reveals some unique discoveries about the evolution of the cartilage that was inside later cartilaginous fish such as sharks , rays , and chimaeras .

gogoselachus

what gogoselachus might have looked like , as restored from the scant fossil remains .
gogoselachus lynnbeazleyae : the first recorded shark from the late devonian gogo formation of western australia .
the fossil , named gogoselachus lynnbeazleyae , is the first shark to be found in this area .
right scapulocoracoid wam 09 . 6 . 145–007 of gogoselachus lynbeazleyae , . . . | download scientific diagram
sciency thoughts : gogoselachus lynnbeazleyae : the first recorded shark from the late devonian gogo formation of western australia .
teeth of gogoselachus are distinctive with many small cusps . the image far right is a ct - scanned tooth showing internal structure .
gogoselachus was clearly a fast - swimming predator that hunted other fishes using its jagged teeth to snare prey . gogoselachus lived on an ancient reef that teemed with many kinds of large predatory placoderm fishes , so had to hold its own in this piscine rat race .
gogoselachus lynnbeazleyae discovered by professor john long at the gogo fossil site , australia . testing shows that the three - dimensional remnant s… | pinteres…
however , when the authors recently examined the microstructure of the cartilage of gogoselachus using micro ct scanning , they discovered the matrix holding the cartilage together in the jaw contained bone cells .
structure of gogoselachus lynbeazleyae endoskeleton . ( a–c ) gogoselachus calcified cartilage ( a ) sem showing tessellate layout ( b , c ) horizontal section through tissue ( d ) transverse ct scan of right meckel ' s cartilage . scale bar is 0 . 1 mm in ( c ) . abbreviations : cp , cell processes ; l , lacunae . long et al . ( 2015 ) .
publishing their findings in the journal plos one , scientists said the fossil of gogoselachus lynbeazleyae dates to the late devonian period , around 380 million years ago , and shows the evolutionary transition from bones to cartilage .
concluding , the authors said the shark is an
exceptionally preserved
fossil that
suggests gogoselachus represents a transitional step toward the tessellated prismatic calcified cartilage which is today recognised as the main diagnostic character of the chondrichthyes
.
but this idea has just been challenged due to the discovery , announced today in the journal plos one , of a 380 - million - year - old fossil shark from western australia named gogoselachus lynbeazleyae that shows remnant bone cells present in its cartilaginous skeleton .
the specimen described by long et al . comprises a set of disarticulated but clearly associated remains comprising both left and right meckel ' s cartilages , nasal cartilage , ceratohyal , hyomandibula , basibranchial cartilage , both scapulocoracoids , and associated teeth and scales . this is described as gogoselachus lynbeazleyae , where ‘ gogoselachus ’ means gogo - shark and ‘ lynbeazleyae ’ honours lyn beazley of the university of western australia for her ‘contribution to scientific progress in western australia’ . the specimen is thought to be the first known acid - prepared mineralized devonian shark remains .
gogoselachus lynbeazleyae is an exceptionally preserved acid - prepared fossil chondrichthyan from the late gogo formation devonian of australia . its lower jaws have an expanded cotylus and small mandibular knob , and the slender scapulocoracoid has just 2 facets for radial articulations . the teeth have well - developed labial cusplets and their structure is intermediate between the ctenacanthiform and symmoriiform condition . the distinctive calcified cartilage forming the endoskeleton has multiple layers of nonprismatic subpolygonal tesserae separated by a cellular matrix . this suggests gogoselachus represents a transitional step toward the tessellated prismatic calcified cartilage which is today recognized as the main diagnostic character of the chondrichthyes .
gogoselachus cartilage showing the separate units called tesserae making the up the lower jaw ( left ) , and a thin section showing bone cells ( red line ) inside the matrix which binds the tesserae together ( right ) . image on the left is 0 . 5mm across , image on right is about 0 . 1mm across .
gogoselachus lynbeazelyae gen . et sp . nov . long , burrow , ginter , maisey , trinajstic , coates , young , senden urn : lsid : zoobank . org : act : ef04ad3e - 865d - 4fa5 - a6ff - f4ed6359fd26 ; urn : lsid : zoobank . org : act : 2ed167f8 - 9506 - 4d43 - b08e - 237291937b11
preparation of gogoselachus lynbeazleyae from the gogo formation , western australia . ( a ) meckel ' s cartilage as exposed on collection , before acetic acid etching . ( b ) specimen during early acid preparation . ( c ) meckel ' s cartilages after full preparation , shown articulated in dorsal view . long et al . ( 2015 ) .
( a–c ) gogoselachus calcified cartilage ( a ) sem wam 09 . 6 . 145–031 showing tessellate layout ( b , c ) horizontal section through tissue wam 09 . 6 . 145–032 ( d ) transverse ct scan of right meckel ' s cartilage . scale bar = 0 . 1 mm in ( c ) . abbreviations : cp , cell processes ; l , lacunae .
fig 4 . right scapulocoracoid wam 09 . 6 . 145–007 of gogoselachus lynbeazleyae , gogo formation , western australia . ( a ) lateral ( b ) posterior and ( c ) medial views , with close up of articulatory area for pectoral fin in e , f . d , articulation area for pectoral fin articulation on left scapulocoracoid for comparison . abbreviations as for fig 3 .
the picture above shows the specimen ( b ) during early acid bath preparation , whilst ( c ) shows the meckelian cartilage once it has been removed from the surrounding rock . the species has been named gogoselachus lynbeazleyae . the genus nomenclature comes from the name of the geological formation and the greek “selachos” which means shark . the trivial name honours neuroscientist professor lyn beazley ( university of western australia ) , in acknowledgement of her role as an ambassador for science .
here we present new data from the first well - preserved chondrichthyan fossil from the early late devonian ( ca . 380–384 mya ) gogo formation lägerstatte of western australia . the specimen is the first devonian shark body fossil to be acid - prepared , revealing the endoskeletal elements as three - dimensional undistorted units : meckel’s cartilages , nasal , ceratohyal , basibranchial and possible epibranchial cartilages , plus left and right scapulocoracoids , as well as teeth and scales . this unique specimen is assigned to gogoselachus lynnbeazleyae n . gen . n . sp .
gogoselachus lynbeazleyae is represented by a set of associated elements which were probably held together by ligaments and muscular tissue when the concretion formed around them . they include both left and right meckel ' s cartilages , nasal cartilage , ceratohyal , hyomandibula , basibranchial cartilage , both scapulocoracoids , as well as associated teeth and scales . fig 1 shows the specimen as it was found in the field ( fig 1a ) , after a week in acetic acid ( fig 1b ) , and after the lower jaws had been freed and reassembled into life position ( fig 1c ) .
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long ja , burrow cj , ginter m , maisey jg , trinajstic km , et al . ( 2015 )
correction : first shark from the late devonian ( frasnian ) gogo formation , western australia sheds new light on the development of tessellated calcified cartilage . plos one 10 ( 6 ) : e0131502 .
the meckel’s cartilages show a jaw articulation surface dominated by an expansive cotylus , and a small mandibular knob , an unusual condition for chondrichthyans . the scapulocoracoid of the new specimen shows evidence of two pectoral fin basal articulation facets , differing from the standard condition for early gnathostomes which have either one or three articulations . the tooth structure is intermediate between the ‘primitive’ ctenacanthiform and symmoriiform condition , and more derived forms with a euselachian - type base . of special interest is the highly distinctive type of calcified cartilage forming the endoskeleton , comprising multiple layers of nonprismatic subpolygonal tesserae separated by a cellular matrix , interpreted as a transitional step toward the tessellated prismatic calcified cartilage that is recognized as the main diagnostic character of the chondrichthyans .
citation : long ja , burrow cj , ginter m , maisey jg , trinajstic km , coates mi , et al . ( 2015 ) first shark from the late devonian ( frasnian ) gogo formation , western australia sheds new light on the development of tessellated calcified cartilage . plos one 10 ( 5 ) : e0126066 . urltoken
academic editor : andrew a . farke , raymond m . alf museum of paleontology , united states
copyright : © 2015 long et al . this is an open access article distributed under the terms of the creative commons attribution license , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited
funding : this work was supported by grants from the australian research council dp 0772138 awarded to gcy and jal for travel and scanning of specimens at the anu ; and dp1092870 awarded to kmt for travel to collaborate . the funders had no role in study design , data collection and analysis , decision to publish , or preparation of the manuscript .
the fossils occur inside limestone concretions which formed around whole fish or parts of carcasses that fell into the deep inter - reef basins between the reef fronts . rapid calcitic concretion formation prevented compaction or distortion from tectonic or gravity - induced sedimentary loading , thus retaining the original shape of the bones and delicate perichondrally calcified cartilages [ 34 ] . geochemical studies indicate that carcasses fell through a euxinic layer within the basin , enabling rare rapid preservation of soft tissue in anoxic benthic conditions [ 43 ] .
( a ) meckel ' s cartilage as exposed on collection , before acetic acid etching . ( b ) specimen during early acid preparation . ( c ) meckel ' s cartilages wam 09 . 6 . 145–001 ( left ) , wam 09 . 6 . 145–002 ( right ) after full preparation , shown articulated in dorsal view .
the field work was done in australia with permission of the land owners and leaseholders . there are no regulations pertaining to collecting of fossils in this region of australia apart from land owner permission as stated under the lands administration act , as relevant to pastoral leaseholders : see urltoken .
the specimen is registered in the collections of the western australian museum as wam 09 . 6 . 145 , repository at 69 kew st , welshpool , western australia .
the specimen was acid prepared at museum victoria , melbourne by jal using 10 % acetic acid , with cartilage elements strengthened by mowital b30 in ethanol . the specimen and residues were washed in water to neutralize the acidity , then picked under a binocular microscope to retrieve isolated scales and teeth .
scanning electron micrographs of teeth , scales and cartilage structure were taken using a jeol - 6400 at the centre for microscopy , university of queensland ( scales ) , and using other sems at university of warsaw , poland ( teeth images ) , and the los angeles county museum of natural history , california ( cartilage ) . thin section images were taken using an olympus bx - 50 microscope with dp12 imaging system .
digital transverse sections of the cartilages were studied through composite serial reconstruction from 10μ slices by the ultrafine ct scanner in the dept of applied mathematics , anu , and studied using drishti 2 . 4 software developed by that department ( and now publically available as freeware ) .
the electronic edition of this article conforms to the requirements of the amended international code of zoological nomenclature , and hence the new names contained herein are available under that code from the electronic edition of this article . this published work and the nomenclatural acts it contains have been registered in zoobank , the online registration system for the iczn . the zoobank lsids ( life science identifiers ) can be resolved and the associated information viewed through any standard web browser by appending the lsid to the prefix
urltoken
. the lsid for this publication is : urn : lsid : zoobank . org : pub : 3563562e - 41e0 - 4579 - 8645 - 9c13f7880019 . the electronic edition of this work was published in a journal with an issn , and has been archived and is available from the following digital repositories : pubmed central , lockss .
qm , queensland museum , po box 3300 , south brisbane bc , queensland 4101 .
wam , western australian museum fossil collection ; 49 kew st , welshpool , wa , 6106 .
generic name for the gogo formation and greek ‘ selachos ’ , shark . species name acknowledging professor lyn beazley , of the university of western australia , for her contribution to scientific progress in western australia .
? deihim mansureae
dubious specimen aeu 236
ginter et al . ( 2002 ; plate 4 , figures j–k ) [ 45 ] .
shark
long & trinajstic ( 2010 ; p . 263 , figure 2 ) [ 34 ]
circa 60 km se of fitzroy crossing , north western australia , near the stromatoporoid camp locality , collected by jal , july 7th , 2005 .
a chondrichthyan with cladodont type teeth characterised by the following combination of features : a crown with a prominent median cusp rounded in cross - section , two smaller lateral cusps , and , in asymmetrical forms , a single intermediate lateral cusplet situated between the median cusp and the mesial lateral cusp ; a row of slender accessory labial cusplets at the crown - base interface ; a euselachian type base with a deep aboral depression and a vague orolingual hump . meckel’s cartilage with wide , transverse articular cotylus and small mandibular knob ; ceratohyal with a deep anterior - facing pit towards the posterior of the outer surface ; elongate basibranchial with straight edges ; scapulocoracoid with two diazonal nerve foramina and two pectoral fin basal articulation facets .
the meckel’s cartilages ( figs 1a–1c ; 2a , 2b and 2g ) are c . 5 cm long , deep posteriorly , with a well - developed continuous dental sulcus for the tooth rows ( sul ) , bordered laterally by a raised straight rim . the outer face of the cartilage has a ventral ridge ( fig 1a , vr ) defining a depressed lateral surface for the insertion of the adductor mandibulae musculature . the lower jaw articulatory surface has a broad transverse cotylus ( fig 2g , cot ) flanked medially by a small mandibular knob ( m . kb ) . both the cotylus and the mandibular process are on the same transverse plane . posterior to the cotylus is a thin vertical lamina ( fig 2a and 2c , re . fl ) , the sustentaculum sensu gegenbaur [ 46 ] a structure that has been recently referred to as the retroarticular flange [ 22 ] . the anterior region of the meckel’s cartilage has a well - defined oval symphysial attachment area ( fig 2b , sym ) with a separate subrectangular muscle attachment area posteroventral to the symphysis ( ma ) .
( a–c ) left meckel’s cartilage wam 09 . 6 . 145–001 , medial , lateral and dorsal views . ( d , e ) ceratohyal wam 09 . 6 . 145–005 , lateral and dorsal views . ( f ) nasal cartilage wam 09 . 6 . 145–006 , anterior vie w ? . ( g ) ? epibranchial cartilage wam 09 . 6 . 145–004 . ( h ) basibranchial cartilage wam 09 . 6 . 145–003 . abbreviations : cot , cotylus ; fl . ch , flange on ceratohyal ; fo . ch , fossa on ceratohyal ; ma , muscle attachment area ; m . kb , mandibular knob ; re . fl , retroarticular flange ; sul , sulcus ; sym , symphyseal pit ; vr , ventral ridge .
the ceratohyal ( fig 2c and 2d ) conforms to the generalized chondrichthyan shape [ 44 , 46 ] , having an expanded posterior blade and narrow , slightly rotated anterior region . it is about three - quarters the length of the meckel’s cartilage , and has a large fossa ( fo . ch ) facing anteriorly at its posterior extremity , rimmed by an elevated flange ( fl . ch ) . the anterior end of the ceratohyal is slightly expanded , with two separate , slightly rugose areas on the medial surface . it bears no distinctive grooves or foramina .
a delicate , triangular double - lamina of twisted cartilage resembles a nasal cartilage ( fig 2f ) . it correlates closely to the size and shape of other primitive chondrichthyan nasal cartilages or parts of the nasal capsule [ 14 ] . a shorter , tubular cartilage preserved above the meckel’s cartilages is one of the gill arches ( fig 2e ) , most likely epibranchial 1 by comparison with ozarcus [ 21 ] . a single elongate and transversely concave cartilage plate probably represents the mineralized surface of a basibranchial cartilage ( fig 2h ) . it has a straight posterior margin with dorsally projecting corners ; the anterior end of the unit is m - shaped . midway along , its convex surface is rough with numerous small pores .
the scapulocoracoid ( figs 3 and 4 ) is 8 . 0 cm high , with an elongate , flat , dorsally tapering scapular region and a deeply concave coracoid region ventral to a thickened posterior ridge at the lateral inflection . the scapular blade has a weak posterolateral process ( pla ) . muscle attachment scars are interpreted as follows : the supinator muscle anteriorly on the lateral surface of the scapula ( sup ) ; the mediolateral pectoral retractor muscles near the anterolateral inflection ( flr ) ; the coracobranchialis muscles ( cobr ) above the inflection ridge ; the coracohyoideus muscles ( cohy ) ventrally ; and the pectoral depressor muscle sheet ( pdm ) on the posterolateral surface of the coracoid ( fig 3a and 3b ) . a ridge ( ri ) along the posterior angle of the ventrolateral inflection shows remnants of areas with raised borders enclosing surfaces presumed to be articulation facets for the pectoral fin basal cartilages . the small central facet is completely preserved on the left side ( fig 3b and 3d , pf . ar2 ) , but the lateral and medial surfaces of the ridge have broken off . the medial area shows remnants of a rim shared with the central area , but the lateral area is missing .
the left scapulocoracoid is slightly damaged in the area of the fin articulation but clearly shows two facets for fin radial articulations ( fig 3d and 3e ) . this interpretation is supported by features preserved in the right scapulocoracoid which has a broad triangular facet for the mesial pectoral fin radial attachment ( fig 4b and 4e , pf . ar1 ) clearly visible , as well as a slightly smaller lateral pectoral fin radial facet ( pf . ar2 ) . restorations combining data from both sides show that there was only two fin radial articulations ( fig 3e , fig 4f ) .
( a ) posterior ( b ) medial and ( c ) lateral views . d , close up of posterior face showing articulation area for pectoral fin , e . , interpretation of same area . f , close up of central lateral surface showing diazonal foramen ( df ) . abbreviations : af , articulation facets ; artc , articular crest ; br , break in bone ; cobr , coracobrachialis muscle attachment area ; cohy , coracohyoideus muscle attachment area ; cp , coracoid plate ; df , diazonal foramina ; muscle attachment areas ; flr , mediolateral pectoral retractor muscle attachment area ; pdm , pectoral depressor muscle attachment area ; pla , posterolateral process ; pf . ar1 , 2 , pectoral fin articulation areas 1 and 2 ; pla , posterolateral angle ; pva , posteroventral angle ; ri , ridge ; sup , supinator attachment area .
( a ) lateral ( b ) posterior and ( c ) medial views , with close up of articulatory area for pectoral fin in e , f . d , articulation area for pectoral fin articulation on left scapulocoracoid for comparison . abbreviations as for fig 3 .
the dentition is represented by some 82 individual cladodont - type teeth which show limited morphological variation ; more than half are relatively large ( width at the base–crown junction 1 . 5–2 mm ; figs 5a–5e ; 6a–6f and 6j–6t ) with the others smaller ( all about 1 mm wide ; fig 6g–6i ) . two types of crowns , symmetrical and asymmetrical , were observed among the larger teeth . symmetrical crowns ( fig 6d–6f and 6n–6t ) have a prominent median cusp , standing upright ( in labial view ) or with a slight distal inclination , and only two divergent lateral cusps whose height usually exceeds one - third of the height of the median cusp . no intermediate cusplets are present . in asymmetrical crowns ( figs 5a–5d ; 6a–6c , 6j–6m ) the median cusp is considerably inclined distally ( up to 20 degrees ) , the distal lateral cusp is inclined distally at 45 degrees and the mesial lateral cusp is only slightly inclined mesially . between the median and mesial cusps there is a small intermediate cusplet . the asymmetrical teeth are wider ( mesio - distally ) than the symmetrical ones . the median cusp is up to 2 . 5 mm in height in symmetrical teeth ; in asymmetrical teeth it is relatively shorter and thicker . in all types of teeth it is rounded in cross section , gently curved lingually , but non - sigmoidal . the labial face is ornamented with two to three coarse cristae almost reaching the tip ; the cristae may bifurcate at the basal part . the lingual face is almost smooth , only one or two indistinct cristae extend along the lateral margins . in asymmetrical specimens they are visible near the mesial margin ( fig 6c and 6j ) . the lingual and labial faces are separated with a lateral carina . the shape and ornamentation of the lateral cusps is similar to that of the median cusp .
large tooth wam 09 . 6 . 145–009 in ( a ) lingual , ( b ) labial , ( c ) oral ( d ) aboral views , in natural light . ( e ) sem of tooth wam 09 . 6 . 145–010 , naturally broken near the median surface . ( f , g ) ct - scans of tooth wam 09 . 6 . 145–011 , showing layout of vascular canals , in basal and lingual - lateral views . abbreviations : l - lcl , labio - lingual canals ; ctcl , central canal ; blcl , basolabial canals ; ccl , coronal canals .
( a–c ) wam 09 . 6 . 145–012 in oral , labial , and lingual views . ( d–f ) wam 09 . 6 . 145–013 in labial , basal , and oblique lateral views . ( g–h ) small tooth , wam 09 . 6 . 145–014 , in lingual , and oral views . ( i ) tooth of intermediate size , wam 09 . 6 . 145–015 , in labial view . ( j–m ) wam 09 . 6 . 145–016 in lingual , labial , oral and distal views . ( n–p ) wam 09 . 6 . 145–017 in oral , labial , and lingual views . ( q–t ) wam 09 . 6 . 145–018 in labial , lingual , oral , and lateral views .
at the crown–base interface , on the labial side of all the teeth , is a row of several accessory cusplets . they display various sizes and directions , but generally are slender , sharp and directed orally . in the asymmetrical specimens the largest may exceed the size of the intermediate cusplet . the labial accessory cusplets are vulnerable to abrasion and in most cases they are broken , leaving only the basal parts preserved .
tooth bases of larger teeth are deep , elongated mesio - distally , from elliptical to broadly hexagonal , to trapezoidal in outline , with a lingual extension . a deep depression in the central / labial area of the aboral side is framed by the well developed , labially convex basolabial rim . no clear interlocking devices ( buttons or basolabial projections ) are present , save for a slight orolingual hump , observed in certain , especially small , specimens . the aboral depression and the basolabial rim might have helped in strengthening the connection between the teeth in a tooth file . the base surface , save for the immediate vicinity of the crown on the oral side and the aboral - lingual area , is perforated by numerous canal openings . the largest foramina occur on the orolingual rim and in the aboral depression .
the ct - scans and broken surfaces reveal a network of basal nutritive canals ( fig 5e–5g ) . in the lingual extension of the base there are mainly labio - lingual canals which , in most cases , extend from the orolingual rim to the lingual wall of the aboral depression . these major canals are interconnected by narrower tubes . in the area of the depression ( i . e . below the crown ; called here central canals ) , the directions change to mainly mesio - distal and vertical . and finally , the canals in the basolabial rim are mainly vertical . from the network of central canals , single vascular canals ( coronal canals ) extend into the basal parts of the median and lateral cusps .
the smaller teeth ( fig 6g–6i ) differ from the larger ones not only by the overall size , but also in proportions between the base and crown—in the smaller teeth , in most cases , the base is relatively broader ( see especially fig 6i ) . in contrast to the excellent preservation of many of the larger teeth , most of the recovered smaller teeth have broken cusps . as the teeth were not found in situ , but dispersed around the jaw cartilages , we can only speculate in reconstructing the dentition . it is most probable that the narrow , symmetrical teeth were on the anterior part of the jaw , and the broader , asymmetrical forms were in the lateral tooth families . the smaller teeth are probably juvenile ones , replaced by larger forms , but preserved on the outer side of jaw , as is common among the ctenacanthiforms [ 47 – 49 ] . the occurrence of both symmetrical and asymmetrical forms among the smaller teeth , as well as their broken ( possibly some worn ) cusps , support this view .
tooth bases resemble the “euselachian - type” ( sensu ginter 2005 ) [ 50 ] in having a spongiose structure and numerous labio - lingual canals . the absence of buttons and basolabial projections is a potential synapomorphy with chondrichthyans possessing
euselachian - type
teeth , although the presence of an orolingual hump and basolabial depression suggests that the bases of successive teeth overlapped in similar fashion to those of cladodont chondrichthyans in which buttons and projections are present [ 47 , 49 – 52 ] . the presence of one or two medially situated larger canals in bases of symmetrical teeth ( fig 6p and 6r ) , instead of evenly distributed canals of virtually the same size , possibly represents a stage between the layout in ctenacanthiforms and symmoriiforms , which have median basal canal openings ( lingual and aboral ) which are usually much larger than any other foramina , and
euselachian - type
teeth with evenly distributed canals .
( a ) presumed flank scale wam 09 . 6 . 145–019 , anterocrown view . ( b , c ) presumed flank scale wam 09 . 6 . 145–020 , anterocrown and posterior views . ( d ) presumed flank scale wam 09 . 6 . 145–021 , posterobasal view . ( e , f ) presumed flank scale wam 09 . 6 . 145–022 , posterobasal view and magnification of undersurface of crown denticulation . ( g , h ) very small scale wam 09 . 6 . 145–023 , broken , showing crown view of one half and basal view of the other half . ( i ) abraded umbellate scale wam 09 . 6 . 145–024 , crown view . ( j , k ) pultschuppe or squamae proniae scale wam 09 . 6 . 145–025 , crown and posterior views . ( l ) stellate tessera wam 09 . 6 . 145–026 , crown view . ( m ) probable branchial denticle plate wam 09 . 6 . 145–027 , lateral view . ( n ) vertical transverse section through presumed flank scale wam 09 . 6 . 145–028 . ( o ) oblique vertical section through umbellate scale wam 09 . 6 . 145–029 . ( p , q ) horizontal section through the crown of ? head tessera wam 09 . 6 . 145–030 , whole section and magnification to show spiralfasern structure . scale bars = 0 . 1 mm in all figures except ( p ) , where scale bar = 1 mm .
thin sections show that the scales grew by appositional addition of odontodes laterally and posteriorly ( fig 7n and 7o ) ; shorter , more upright odontodes are added anteriorly . the thin bone bases show several inner growth zones having separate bases , with bases underlying the whole scale formed only in the later growth periods ( fig 7n and 7o ) . each odontode has a relatively wide pulp canal , surrounded and partly infilled by ‘spiralfasern’ , and interconnected by radial and circular canals . the ‘spiralfasern’ structure ( sensu gross ) [ 54 ] , rather than being fibrous , appears to be formed by spiralling rings of atubular dentine which developed centrifugally to partly fill the wide pulp canals . fine branching dentine tubules permeate the outer solid areas of the odontodes . innermost ( oldest ) odontodes have separate ? acellular bone bases , but the youngest growth zones have bases which underlie new and old growth zones . sharpey’s fibres extended through the full - width zones , but not the individual odontode bases . horizontal section of a pultschuppe scale shows centrifugal growth zones ( fig 7p and 7q ) .
the endoskeletal elements are formed of mineralized tessellated cartilage ( fig 8 ) that varies in thickness , corresponding to the number of layers of tesserae . the meckel’s cartilages , scapulocoracoids and the median ventral section of the basibranchial unit have two layers , whereas the gill - arch cartilages and the articulatory block on the scapulocoracoid are finer , with mostly one but rarely two layers . thin sections of loose cartilage fragments ( fig 8b and 8c ) show a structure similar to typical shark tessellated calcified cartilage , with subpolygonal tesserae showing rings and waves of liesegang [ 55 ] . however , rather than having fibrous connections between the tesserae as found in modern sharks [ 56 ] , the tesserae are mostly surrounded by a matrix incorporating elongate lacunae , some with fine processes extending from them ( fig 8c ) . ct scans ( fig 9h ) show the varying thickness of the cartilage in different areas of the endoskeletal elements ( fig 8d ) .
the morphology of the teeth is unique among the devonian chondrichthyes , showing a mix of features found in several shark groups . the crown is somewhat similar , mostly in the proportions of the cusps , to that of ctenacanthus concinnus [ 64 ] and cladodoides wildungensis [ 65 , 66 ] , but the median cusps of the latter two are labially flattened whereas in gogoselache lynbeazleyae they are biconvex . the asymmetry in devonian ctenacanthids , albeit common , is never advanced to a point of occurrence of an intermediate cusplet only on one side . moreover , the tooth base in ctenacanthids is provided with a distinct orolingual button and a straight , shelf - like basolabial projection , which are missing in g . lynbeazleyae teeth .
( a–c ) arduodens flammeus hairapetian & ginter , 2009 , from chahriseh , aeu 610 , in lingual , aboral , and lateral views . ( d–g ) deihim mansureae ginter , hairapetian and klug , 2002 . ( d , e ) holotype , igpuw / ps / 5 / 1 , from hutk , in oral and lateral views . ( f , g ) putative anterior tooth , aeu 239 , from hodjedk , in labial and oral views . scale bar = 0 . 5 mm .
based on isolated teeth from the famennian of iran , ginter et al . [ 45 ] proposed a strong heterodonty within the dentition of d . mansureae . most of the specimens attributed to that species are various forms of crushing teeth . only two specimens can be considered as clutching teeth , and these were tentatively included in d . mansureae because of the structure of the base and the presence of labial accessory cusplets . it was suggested [ 45 ] that the teeth were from the anterior tooth families and the whole dentition functioned in a way similar to modern heterodontus , with a few minute anterior clutching teeth and a large lateral and posterolateral crushing apparatus ( [ 68 ] fig24c ) . however , the reconstructed whole dentitions of g . lynbeazleyae and d . mansureae were completely different , with a total absence of crushing teeth associated with wam 09 . 6 . 145 . therefore , we consider g . lynbeazleyae and d . mansureae to belong to separate , albeit probably related , genera .
a single tooth from the upper devonian of the canning basin , western australia , emerikodus ektrapelus [ 69 ] bears some similarity to the new form . the preservation of the tooth is not very good , but the form of the main parts of the crown and base are quite similar to those of g . lynbeazleyae . however emerikodus displays one very unusual feature : the row of accessory cusplets is apparently situated on the lingual , and not labial , side of the crown .
the presumed normal body scales of gogoselache lynbeazleyae appear intermediate between the ‘cladodont’ type sensu gross [ 53 ] and the ctenacanthid type sensu reif [ 70 ] . the ‘cladodont’ scale category was based on isolated scales from the middle devonian ohio bonebeds [ 54 , 71 ] and the upper devonian of iowa , rhineland and harz [ 54 ] . the scales are characterized by having a base formed of lamellar bone layers penetrated by sharpey ' s fibres , and a crown plate comprising circular or semicircular zones of odontodes ; growth was by addition to the margin of the scale crown and a new ( cellular or acellular ) bone layer under the whole base .
several occurrences of ctenacanthid and cladodont type scales have been reported from eastern and western australian middle to late devonian microvertebrate assemblages [ 72 – 74 ] . other rich assemblages from the ? upper givetian aztec siltstone at mt crean , antarctica include ctenacanthid - type scales similar to those of gogoselache , that are most likely from antarctilamna prisca [ 75 ] . the acanthodian and chondrichthyan microremains in the mt crean assemblage [ 76 ] show a marked similarity to early frasnian faunas from iran [ 77 ] .
comparing gogoselache scales with those of older taxa , the flank scales with their concave bases and polyodontode crowns resemble those of leonodus mader from the lochkovian of northern spain [ 78 ] . doliodus problematicus from the early emsian of new brunswick , canada [ 15 ] , and antarctilamna prisca young from the givetian of antarctica [ 75 ] . unlike gogoselache , all of these taxa have diplodont teeth , indicating that the scale form is probably ancestral to both shark lineages determined by tooth morphology .
the structure of the calcified cartilage in the endoskeleton of gogoselache is of interest as an apparent transitional form between gcc and pcc . ct scans and thin sections show a calcified tissue forming the outer shell of endoskeletal elements , more derived than the simple calcified cartilage comprising separate globules found in osteostracan agnathans [ 55 ] , acanthodians [ 79 ] and some stem chondrichthyans ( fig 9a and 9b ) . placoderms differ from other gnathostomes in having perichondral bone plus globular ( gcc ) and / or uncalcified cartilage forming their endoskeleton ( fig 9c and 9d ) in instances where such elements are preserved at all [ 53 , 73 , 80 ] .
we would like to thank field team members of the 2005 gogo expedition , l . hatcher , m . nossal , b . choo and m . karkeek ; and r . f . miller ( nbmg ) for image of doliodus calcified cartilage . we thank giar - ann hung for assistance with the sem photography at la county museum of natural history . dr adam summers , university of washington , provided helpful discussion on the cartilage histology . this work is a contribution to igcp 596 .
conceived and designed the experiments : jal cjb jgm mic mg kmt gcy tjs . performed the experiments : jal mic tjs gcy jgm . analyzed the data : jal kmt cjb tjs gcy jgm mic mg . wrote the paper : jal cjb mg jgm mic . collection and preparation of the specimen : jal .
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sharks are one of the oldest and least changed of all the living back - boned jawed creatures . but because their skeletons are made of cartilage much of their early fossil record is poor .
cartilage is a rubbery tissue that forms the framework for bones to ossify ( harden ) upon . it’s why babies have rubbery legs when they begin to walk , as the bones haven’t fully ossified around the cartilage cores . our ears and noses have cartilage frameworks too , which lack bone , but still support the soft structures we hear and smell with .


the kelp gull ( larus dominicanus ) , also known as the dominican gull , is a gull which breeds on coasts and islands through much of the southern hemisphere .

the nominate l. d. dominicanus is the subspecies found around south america , parts of australia ( where it overlaps with the pacific gull ) , and new zealand ( where it is known as the southern black-backed gull or by its māori name karoro ) .

l. d. vetula ( known as the cape gull ) is a subspecies occurring around southern africa .

the specific name comes from the dominican order of friars , who wear black and white habits .

kelp gull

kelp gull : molting juvenile default description kelp gull : molting juvenile kelp gull : winter adult default description kelp gull : winter adult kelp gull : adult default description kelp gull : adult kelp gull : 2nd summer default description kelp gull : 2nd summer related birds lesser black - backed gull great black - backed gull general kelp gull : large and stocky gull with white head , underparts , and tail . more
a kelp gull stands near a newborn seal in namibia ' s dorob national park .
the kelp gull habitually drops molluscs from the air onto rocks to smash them open .
whereas the nominate kelp gull usually has a pale eye . young cape gulls have almost identical plumage to similarly aged kelp gulls . more
the kelp gull is native to south america , australia , parts of africa and the caribbean . the range of this bird species is about 10 million square kilometers . the population of the kelp gull is about 3 . 5 million individual birds . the rating of the kelp gull at this time is least concern . the prior rating for the kelp gull was lower risk , which was downgraded to least concern in 2004 due to the range and population of the kelp gull . there are no known threats facing the range or the population of the kelp gull at this time .
the kelp gull resembles larus pacificus – pacific gull , but the latter has white tail with black subterminal band , and its bill is larger .
aspects of the topic kelp gull are discussed in the following places at britannica . assorted references * description ( in gull ( bird ) ) the kelp gull ( l . dominicanus ) is a very wide - ranging black - backed species of the southern hemisphere , including antarctica . the laughing gull ( l . more
the kelp gull forages on land or in water , rarely in the air . it feeds mainly on fish and crustaceans , but will scavenge when an opportunity arises . like the pacific gull , the kelp gull habitually drops molluscs from midair onto rocks to smash them .
the kelp gull prefers the sheltered parts of coasts such as bays , inlets and estuaries ; also beaches and reefs on off - shore islands . it is likely that the kelp gull is in serious competition with the endemic pacific gull because of their similar habitat , food and habits .
the kelp gull is the second largest gull in the region , being smaller and less bulky than the pacific gull , larus pacificus , and with a less massive bill . its tail is all white , with no black band . immature kelp gulls can also be confused with the vagrant black - tailed gull , larus crassirostris , from japan .
thibaut chansac and stanislas wroza endured a testing day on a paris landfill , eventually clinching an elusive ' black - backed gull ' as france ' s second kelp gull .
kelp gulls occasionally become entangled in fishing lines , are occasionally illegally shot , and have been poisoned . in new zealand , the kelp gull was regularly eated by the maori .
kelp gull ( larus dominicanus dominicanus ) adult , february 28 2009 , maitencillo , chile . picture : josé canas .
kelp gull ( larus dominicanus vetula ) adult , may 17 2015 , maputo , mozambique . picture : ross hughes .
kelp gull ( larus dominicanus veltula ) adult , june 30 2007 , south africa . picture : j . avise .
the latest sighting details and map for kelp gull are only available to our birdguides ultimate or our birdguides pro subscribers .
kelp gull ( larus dominicanus dominicanus ) adult , january 13 2012 , elqui prov . chile . picture : blass bass .
kelp gull ( larus dominicanus dominicanus ) adult , february 21 2015 , muriwai , new zealand . picture : christina port .
kelp gull ( larus dominicanus vetula ) 2nd cycle , april 26 2015 , maputo , mozambique . picture : gary allport .
kelp gull ( larus dominicanus vetula ) adult , june 2012 , cape town , south africa . picture : chris gibbins .
kelp gull ( larus dominicanus vetula ) adult , july 25 2007 , kommetjie , south africa . picture : graham ekins .
kelp gull ( larus dominicanus dominicanus ) adult , september 09 2009 , bahia inglesa , chile . picture : jason quinn .
kelp gull ( larus dominicanus dominicanus ) adult , november 26 2011 , isla magdalena , chile . picture : antonio vaccarini .
kelp gull ( larus dominicanus dominicanus ) adult , november 08 2006 , karoro , new zealand . picture : brian gratwicke .
kelp gull ( larus dominicanus veltula ) adult , january 06 2012 , neko harbour , antarctic peninsula . picture : michael shepard .
kelp gull ( larus dominicanus dominicanus ) adult , march 16 2014 , petorca prov . , chile . picture : gonzalo vergara .
kelp gull ( larus dominicanus vetula ) adult , september 25 2010 , hout bay , south africa . picture : dick daniels .
kelp gull ( larus dominicanus vetula ) adult , february 24 2015 , walbis bay , namibia . picture : rafael g . sánchez .
kelp gull ( larus dominicanus dominicanus ) adult , april 18 2008 , la perouse , sidney , australia . picture : mr troy .
kelp gull ( larus dominicanus dominicanus ) adult , june 02 2009 , la perouse , sidney , australia . picture : mr troy .
kelp gull ( larus dominicanus vetula ) adult , july 17 2012 , cape cross seal reserve , namibia . picture : tom heijnen .
an adult kelp gull or cape gull ( larus dominicanus vetula ) found and photographed today , 25 january , at the fish factory of anza near agadir by arie ouwerkerk and jacob jan de vries .
the yelping ' yo - yo - yo - yo ' call of the kelp gull is used in many films with coastal or marine scenes .
the races “ judithae ” and “ melisandae ” were described in 2002 , and evaluated as kelp gull’s subspecies on the basis of morphological characters .
kelp gull ( larus dominicanus dominicanus ) adult , january 09 2014 , robert island , south shetland islands , antarctica . picture : david cook .
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the kelp gull occurs in coastal bays , beaches , inlets and estuaries and on off - shore islands . they are often seen scavenging at refuse tips
quintana rd , travaini a ( 2000 ) characteristics of nest sites of skuas and kelp gull in the antarctic peninsula . j field ornithol 71 : 236–249
normally , the kelp gull is expected at khniffiss lagoon and along the southern moroccan atlantic coast , but they do occur north of khniffiss as well .
this subspecies differs markedly from other kelp gull subspecies , especially in skull structure ( a notably flatter crown ) , and some texts ( examples will foolow ) treat this form as a distinct species , known as cape gull . however there is no molecular evidence to support this and we follow urban et al . in treating it as a subspecies of kelp gull larus dominicanus .
* the kelp gull is the only gull of the southern ocean . * kelp gulls are aggressive predators taking every opportunity to rob other birds ' nests of both eggs and small chicks . description & characteristics : the kelp or dominican gull lives on the antarctic peninsula and at most sub - antarctic islands , where it is resident year - round , generally in small numbers . they are also broadly distributed throughout southern africa , australasia and south america . more
the kelp gull is a large black - backed gull with a white tail and a large yellow bill with a red spot on the lower tip . it is the second largest gull in australia . the wing has a wide trailing edge and a small white ' window ' in the wingtip . newly - fledged kelp gulls are brown with paler mottling on the hind neck and breast and have a black bill . immature kelp gulls have mottled brown wings and back with a whitish body and an all - yellow bill . the kelp gull is gregarious , and tends to roost , feed and breed in flocks .
the kelp gull is classified as least concern . does not qualify for a more at risk category . widespread and abundant taxa are included in this category .
kelp gull , larus dominicanus vetula , in flight . kelp gull in flight at houtbay harbor . the nominate race of the kelp gull ( larus dominicanus ) occurs along the coasts of south america , new zealand , australia and many islands in the southern ocean . the subspecies found along the southern african coastline , l . d . vetula , is currently thought to be sufficiently different from the nominate race that it ought to be regarded as a full species . more
in some areas the kelp gull is considered a ‘nuisance’ species , often concentrated close to cities and thought to pose a potential health threat to humans , leading to calls for its populations to be controlled . however , no kelp gull colonies are currently under any kind of management ( 7 ) . it is also thought that increasing kelp gull populations could have a negative effect on other coastal wildlife , for example through increased harassment of other sea birds ( 7 ) ( 8 ) . more
blackish upperparts and thick bill in kelp gull give it a great black - backed gull impression . kelp gull is quick in attaining a dark saddle , where great black - backed gull keep anchor - patterned scapulars for a prolonged period . also , kelp gull remain to show very limited white in the primaries ( either the tips and the mirror , see picture below ) , while great black - backed gull quickly develop a mirror on p10 ( in 2nd gen p10 ) and normally develop large white tips , even obvious on outermost primaries in many immature birds . a very small mirror on p10 and absence of a p9 mirror in adult kelp gull give it a completely different , dark , wingtip impression when compared to adult great black - backed ( which has a merged mirror and white tip on p10 and always a very large mirror on p9 as well in adult plumage ) .
kelp gull ( larus dominicanus vetula ) adult , november 07 2012 , kenton - on - sea , eastern cape , south africa . picture : wikipedia - snowmanradio .
crawford rjm , cooper j , shelton pa ( 1982 ) distribution , population size , breeding and conservation of the kelp gull in southern africa . ostrich 53 : 164–177
the african subspecies l . d . vetula is sometimes split as the cape gull , l . vetula . it has a more angular head and a smaller shorter bill . the adult has a dark eye , whereas the nominate kelp gull usually has a pale eye . young cape gulls have almost identical plumage to similarly aged kelp gulls .
subspecies and range : the kelp gull can be considered a monotypic species , awaiting more information about the subspecies . however , the 5 currently recognized races can be mentioned .
good t ( 2002 ) breeding success in the western gull × glaucous - winged gull complex : the influence of habitat and nest - site characteristics . condor 104 : 353–365
kelp gull dominicanus 2nd cycle , december 10 2012 , australia ( mick ) . upperparts tone equals great black - backed gull , but this taxon has much more black in the wingtip ( marinus in this plumage would show large mirrors already ) . note yellowish legs .
the kelp gull occurs on coasts and islands through much of the southern hemisphere from new zealand and most sub - antarctic islands , the antarctic peninsula , south america , and africa .
kelp gull dominicanus 2nd cycle , september 24 2011 , lima , peru ( john turner ) . upperparts tone equals great black - backed gull , but this taxon has much more black in the tail , plain brown coverts , bright yellow on bill and lacking pale primary tips .
introduction : the kelp gull is present through much of the southern hemisphere . according to the authors , 4 or 5 subspecies are recognized , but kelp gull’s taxonomy is still in a state of uncertainty . as this species has extremely wide range , more subspecies might be added in the future . however , you will find on this page numerous pictures from several locations in the southern hemisphere .
in many cases , once a gull pecks out the eyeballs , other kelp gulls join in and begin to eat the seal’s exposed areas , such as its underbelly and genitals , the scientists observed .
the kelp gull breeds on islands , both oceanic and offshore , on headlands , cliffs above the sea , beaches , pastures and lava fields according to the range , and even in urban areas .
kelp gull dominicanus adult , june 30 2007 , south africa . picture : j . avise . upperparts tone equals great black - backed gull , but this taxon has much more black in the wingtip , with just a tiny mirror on the outer primary . often yellowish legs and dark iris .
kelp gull in flight , andean mountains above ushuaia in the background , larus dominicanus , beagle channel purchase a print of this imagehow to request , purchase or license this imageadd to light table sea birds ( likely western and / or heermanns gulls ) on drift kelp , open ocean , larus occidentalis , larus heermanni , san diego , california purchase a print of this imagehow to request , purchase or license this imageadd to light table kelp gull in flight , andean mountains above ushuaia in the background . more
a bird calling while standing on a beach . an immature pacific gull can also be heard .
the kelp gull is resident in many parts of australia , in others it is dispersive although this varies from colony to colony . in some colonies , parts of the population are apparantly resident or sedentary .
the kelp gull first become established in australia in the 1940s . their numbers increased rapidly and they are now found in many parts of the south - east and south - west coasts of mainland australia .
in the study , kelp gulls were successful in plucking out eyeballs in roughly 50 percent of observed attacks .
kelp gull is the dominant large gull species of south america . it is common throughout the southern part of the continent and extending north along the coasts to ecuador in the west and brazil in the east , though it is also known as a vagrant and occasional breeder north to the united states as well . large , with very dark black upperparts and pale yellow - green legs , this gull is easily distinguished from other gulls in its range . kelp gulls feed on a variety of land and marine animals and also attend refuse dumps .
researchers speculate that the kelp gull population increased decades ago with the development of fish processing in the area . waste from processing plants may have attracted gulls into the area , which then learned to get more food from whales .
burger j , gochfeld m ( 1981 ) nest site selection by kelp gulls in southern africa . condor 83 : 243–251
management and research actions suggested to address these problems include monitoring of kelp gull colonies , particularly close to urban areas , as well as an evaluation of the effects of the gulls on other coastal species , and more careful treatment and disposal of refuse , sewage and fish offal , to discourage scavenging and to help control gull numbers ( 7 ) . given the kelp gull’s abundance and large range , and its presence in many protected coastal areas , the threats to the species are not thought likely to pose any conservation problems in the near future ( 7 ) .
kelp gull prey on and scavenge molluscs , fish , crustaceans , other seabirds , and even their own chicks and eggs . they are opportunistic , and their diet varies with season and among localities depending on the availability of food .
physical description & related species : kelp gull have a white head , neck , underbody , rump and tail . the saddle and upperwing is slate - black with a white leading edge . the wingspan is 106 - 142 cm . the yellow bill has a rounded red subterminal spot at the gonys . distribution & abundance - distribution : kelp gull are broadly distributed in the subantarctic to subtropical regions , where sea surface temperatures range from 0° to 23° c . more
54–65 cm ; 810–1335 g ; wingspan 128–142 cm . four - year gull . intermediate in size and build between
kelp gulls are eating the eyeballs from newborn cape fur seals—a behavior never before seen in nature , a new study says .
in some areas the kelp gull is considered a ‘nuisance’ species , often concentrated close to cities and thought to pose a potential health threat to humans , leading to calls for its populations to be controlled . however , no kelp gull colonies are currently under any kind of management ( 7 ) . it is also thought that increasing kelp gull populations could have a negative effect on other coastal wildlife , for example through increased harassment of other sea birds ( 7 ) ( 8 ) . in particular , this gull has recently developed the habit of gouging skin and blubber from the backs of southern right whales , opening up lesions and causing the whales to take evasive action ( 2 ) ( 8 ) . it is feared that increasing harassment may compromise calf development and even cause the whales to leave the affected areas ( 8 ) .
the latest sighting details and map for cape gull are only available to our birdguides ultimate or our birdguides pro subscribers .
cape gull ( larus dominicanus vetula ) , anza , morocco , 25 january 2016 . ( jacob jan de vries )
known widely as ‘kelp gull’ in other countries , the same species is also common in similar latitudes around the southern hemisphere , including southern australia , south america , southern africa , and most subantarctic and peri - antarctic islands , and the antarctic peninsula .
the kelp gull breeds in colonies , occasionally as isolated pairs . they are monogamous , but the pair - bonds last about one year , from one season to the next breeding period . they usually strengthen the bond by courtship feeding during the winter . the colonies are noisy . alarm calls are given as soon as predators are approaching . the gulls may perform communal mobbing and attack in active defence . the kelp gull is territorial and defends an area around the nest , because cannibalism occurs towards the chicks of the neighbour nests .
the kelp gull is a large bird with slate - black wings , a white head and body , and an all - white tail . the underwing is white , tipped black , and the dark upperwing bears a white bar , with white markings on the wing tips . the beak is yellow , with a conspicuous red spot on the lower mandible , and the yellow eye is surrounded by an orange - red ring ( 2 ) ( 3 ) ( 4 ) . the pale eyes , together with greenish - yellow rather than yellow legs , and a larger , more robust body , help distinguish the kelp gull from the similar - looking lesser black - backed gull ( larus fuscus ) ( 2 ) ( 5 ) . the male and female kelp gull are similar in appearance ( 3 ) , while non - breeding adults have brown mottling on the head and neck ( 2 ) . juveniles are dark brown and mottled , with a blackish tail , dark beak , brownish legs and brown eyes ( 2 ) ( 3 ) . adult plumage is usually attained by the fourth year ( 2 ) . the kelp gull’s call is a loud ki - ok , and the alarm call is a short , repeated pok ( 5 ) .
the kelp gull nests in loose colonies or scattered single pairs on off - shore islands where breeding birds maintain large territories against other gulls . the nests of kelp gulls can be a well - made bowl of plants stems , grasses and seaweeds or a loose pile of material on the ground , near rocks or in a tussock . both the adults build the nest , incubate the eggs , brood and feed the young .
calls and songs : sounds by xeno - canto the kelp gull utters strident “kee - och” , and we can also hear melancholy “yo - yo - yo - yo - yo” and repeated “kwee - ah , kwee - ah , kwee - ah” . it is noisy during the breeding season and while feeding , but also during aggressive interactions . calls and songs are fairly similar to those of other gull species .
a new study suggests that increased attacks by kelp gulls on southern right whale calves could be contributing to an observed increase in mortality among the latter .
“it’s a cruel way to go , ” says gallagher . but from the gull’s point of view , it’s a “beautifully strategic attack . ”
southern black - backed gull . adult . boulder bank , nelson , january 2008 . image © rebecca bowater fpsnz by rebecca bowater fpsnz urltoken
garcía borboroglu p , yorio p ( 2004a ) habitat requirements and selection by kelp - gulls in central and northern patagonia , argentina . auk 121 : 243–252
protection / threats / status : the kelp gull has large range and it is common and conspicuous in most part of its distribution . the overall population is increasing with agriculture and fishery expansion . it is often considered a pest in urban areas , and might have negative effect on the coastal wildlife , through harassment and predation towards other bird species and small animals . the falkland’s population is about 30 , 000 breeding pairs . the global population is estimated to number 3 , 300 , 000 / 4 , 300 , 000 individuals . the kelp gull is not currently threatened , and evaluated as least concern .
the kelp gull is the second largest of australia ' s gulls ( 550 - 580 mm ) . adults have a white head , neck , underbody , rump and tail . the upperparts and wing are black with a white leading edge . the yellow bill has a red spot on the lower tip .
kelp gulls are opportunistic omnivores and will scavenge as well as prey on molluscs , fish , crustaceans , other seabirds , and even their own chicks and eggs .
fordham ra ( 1964 ) breeding biology of the southern black - backed gull . i . pre - egg and egg stage . notornis 11 : 3–34
jehl jr jr , mahoney sa ( 1987 ) the roles of thermal environments and predation in habitat choice in the california gull . condor 89 : 850–862
recent populations of kelp gulls have increased in some locations perhaps due to human subsidies : trawler fish discards , scraps from fish processing plants , and coastal rubbish piles .
though , so perhaps it’s wisest to stick with kelp gull for the time being… according to urltoken “kelp gulls breed in namibia and south africa ; there are large colonies between cape cross and the islands in algoa bay , with occasional nests recorded as far north as cape fria and as far east as the great fish river . along the west coast , nonbreeding birds occur north to luanda , angola , and along the east coast as far as the limpopo river mouth in mozambique . more
while many larid species have benefited from the presence of people , two tern and one gull species have become endangered . least and roseate terns are threatened by destruction and disturbance of their nest sites on sand bars and beaches while the sharp decline of the ivory gull could be related to pollution and global warming .
bird was a kelp gull , knowing well the possibility of a hybrid such as
chandaleur
gulls . below is my own description of this bird ( written at 7 pm , 8 nov 2008 ) , independent of any discussions with ron after the initial sighting and independent of examining any reference books / sources . overall impression : this was a large , dark - backed gull in adult plumage . it was significantly larger than the laughing and franklin ' s gulls in the area . more
the vetula subspecies of kelp gull breed on 81 known localities on the coast of southern africa from ilha dos tigres in southern angola , along the namibian and atlantic coasts of south africa , round the cape as far east as the riet river , near port alfred on the indian ocean coast in the eastern cape province of south africa ( ref : roberts birds of southern africa ) . this gull is also colonising inland locations up to 10km from the coast on the skeleton coast in namibia .
miskelly , c . m . 2013 . southern black - backed gull . in miskelly , c . m . ( ed . ) new zealand birds online . urltoken
native to coastlines of the southern hemisphere , this big gull was a shock to birders when it began showing up in north america in the late 1980s . from 1989 into the 1990s , several adults were present on the chandeleur islands , in the gulf of mexico off the coast of louisiana . a few pairs even nested there , and other kelp gulls interbred with herring gulls on the islands , producing hybrids . during the 1990s , a few kelp gulls wandered elsewhere in north america , including texas , maryland , and indiana , and there have been scattered records since then . “pure” kelp gulls may not occur on the chandeleur islands any more , but some apparent hybrids are still wandering in the gulf of mexico .
the kelp gull breeds on coasts and islands through much of the southern hemisphere . it is found on a number of subantarctic islands , on the antarctic peninsula , on the southern coast of australia and all of new zealand , on the southern cost of africa and madagascar , and on the coast of south america as far north as ecuador and southern brazil 1 .
habitat : the kelp gull usually occurs along the coasts , especially in south africa . but throughout the range , it also frequents large inland lakes in the andes of argentina . it also feeds and roosts around lakes , including smaller mountain lakes in new zealand . it also frequents reservoirs , estuaries and rivers . it can be seen in farmland and lawns too .
kelp gull : widespread along coasts and on islands throughout the southern hemisphere , occurring in southern africa , madagascar , australia , new zealand , south america and the falkland islands , as well as on antarctica and many sub - antarctic islands . found in a variety of habitats including harbors , bays , inlets , estuaries , beaches and rocky shores . accidental in maryland .
the yelping ' yo - yo - yo - yo ' call of the kelp gull is used in many films with coastal or marine scenes . facts and figures research species : no minimum size : 49 cm maximum size : 62 cm average size : 57 cm average weight : 940 g breeding season : september to december . clutch size : two to three . more
ty - jour ti - taxonomy of the kelp gull larus dominicanus lichtenstein inferred from biometrics and wing plumage pattern , including two previously undescribed subspecies t2 - bulletin of the british ornithologists ' club . vl - 122 ur - urltoken pb - british ornithologists ' club , cy - london : py - 2002 sp - 50 ep - 71 sn - 0007 - 1595 er -
kelp gull dominicanus adult , january 06 2012 , antarctic peninsula ( michael shepard ) . birds on the southern hemisphere are in complete moult in our winter months . here moult in inner primaries p1 new , p2 groiwng , p5 - p10 old . dark as marinus , but much more black in wingtip with just a small mirror on p10 and full broad band on p5 .
fordham , r . a . 1968 . dispersion and dispersal of the dominican gull in wellington , new zealand . proceedings of the new zealand ecological society 15 : 40 - 50 .
in the subantarctic , kelp gulls lay three eggs in november to december . incubation and fledging periods are 23–30 days and 45–61 days , respectively . parents sometimes continue to feed their chicks after fledging .
l . d . vetula is found on the coasts of south africa and namibia . this race has greyer legs and feet , and dark brown eyes . it is known as cape gull .
the kelp gull is widespread along coasts and on islands throughout the southern hemisphere , occurring in southern africa , madagascar , australia , new zealand , south america and the falkland islands , as well as on antarctica and many subantarctic islands ( 2 ) ( 3 ) ( 4 ) ( 6 ) . although largely sedentary , some southern populations migrate north outside of the breeding season ( 2 ) ( 3 ) .
rowntree , v . j . ( 1998 ) increased harassment of right whales ( eubalaena australis ) by kelp gulls ( larus dominicanus ) at península valdés , argentina . marine mammals science , 14 : 99 - 115 .
the kelp gull breeds between september and january , in colonies numbering from one to several hundred pairs ( 2 ) ( 6 ) . the species is monogamous , with pair bonds usually maintained from one breeding season to the next , and strengthened by courtship feeding during winter months . both adults help to incubate the eggs and raise the chicks ( 4 ) . the nest , built on bare rock , sand or mud , often in a well - vegetated site , is a large and bulky structure , constructed from dried vegetation or seaweed ( 2 ) ( 4 ) ( 6 ) . around 3 eggs are laid ( 2 ) ( 4 ) , which hatch after 24 to 30 days , the young kelp gulls fledging approximately 7 weeks later ( 2 ) . kelp gulls begin to breed from around three to four years old , and may live for 20 years ( 4 ) .
there is one common issue in peninsular valdes that i feel is important to highlight . in puerto madryn there was a fish processing factory that for many years had uncovered waste sites and this led to a massive boom in the kelp gull population . the numbers got that big that eventually more and more birds started to copy an originally small number of kelp gulls who fed on the whales by landing on a whale as it was at the surface and pecking through the skin and into the blubber . after this behaviour was first noticed there were campaigns for the fish factory to dispose of the waste more responsibly and now they move it a few kilometres further inland .
a melancholy
yo - yo - yo - yo - yo
which is unlike the call of any other tasmanian gull and will sound familiar as part of the soundscape of films and movies set on coastlines .
a common , widespread species with a large global population , the kelp gull is not currently considered globally threatened ( 2 ) ( 6 ) , and may even have increased with the expansion of agriculture and fisheries ( 2 ) . potential threats to the species include oil spills , diseases such as avian cholera and avian botulism , mortality from interactions with trawler warp cables , persecution by humans , and disturbance at breeding sites ( 6 ) ( 7 ) .
behaviour in the wild : the kelp gull is an opportunistic feeder like numerous laridae . it feeds on a variety of aquatic preys such as fish , molluscs , worms , echinoderms , arthropods , but also reptiles , amphibians , birds , small mammals and occasionally berries . it is also a scavenger and can be seen at rubbish and sewage , and carrion and fish offal . but this gull may sometimes take sickly lamb and young poultry . it is able to attack and kill adult birds as large as geese . it often follows the fishing boats and forages around the slaughterhouses and seafood factories . it is known for stealing food from other seabirds , laridae and also spheniscidae .
larids are found near fresh and salt water throughout north america but are most common near large bodies of water . even marsh nesters such as the franklin ' s gull and black tern spend the winter in coastal areas .
during the past 15 years , scientists have logged around 500 instances of kelp gulls ( larus dominicanus ) attacking and attempting to eat the eyeballs of newborn cape fur seals ( arctocephalus pusillus pusillus ) in namibia ’s coastal dorob national park ( map ) .
kelp gulls are broadly distributed in the subantarctic to subtropical regions , where sea surface temperatures range from 0° to 23° c . they can mostly be seen off the new zealand coasts and islands , and along the south and south - east australian coasts .
great black - backed gull ( marinus ) 2nd cycle , february 02 2012 , ijmuiden , the netherlands ( mars muusse ) . no blackish saddle . 2nd gen primaries with rounded pale tips . limited black in tail . chequered coverts .
kelp gulls have a white head , neck , underbody , rump and tail . the saddle and upperwing is slate - black with a white leading edge . the wingspan is 106–142 cm . the yellow bill has a rounded red subterminal spot at the gonys .
the displays are accompanied by calls . the most frequent is the “long - call” , often given from the ground or sometimes while flying . the gull raises the head and gradually lowers it while uttering a series of long notes . this display is usually followed by “head - tosses” during which the gull throws the head up over its back while giving a plaintive note . once the pair is formed , both mates call and display every day , and courtship feeding is frequently observed .
burger , j . , gochfeld , m . , garcia , e . f . j . & kirwan , g . m . ( 2018 ) . kelp gull ( larus dominicanus ) . in : del hoyo , j . , elliott , a . , sargatal , j . , christie , d . a . & de juana , e . ( eds . ) . handbook of the birds of the world alive . lynx edicions , barcelona . ( retrieved from urltoken on 9 july 2018 ) .
gulls , terns , and the black skimmer are all migratory with the larger gulls migrating short distances to open water and the sabine ' s gull , terns , and black skimmer undertaking incredible journeys to the seas and rivers of the southern hemisphere .
yorio , p . , bertellotti , m . , gandini , p . and frere , e . ( 1998 ) kelp gulls larus dominicanus breeding on the argentine coast : population status and relationship with coastal management and conservation . marine ornithology , 26 : 11 - 18 .
the kelp gull has become established in australia since the 1940s , with the first breeding recorded on moon island near lake macquarie in new south wales in 1958 . their numbers have increased rapidly since the 1960s and they are now common in many parts of the south - east and south - west coasts , and especially in tasmania . it is widespread in new zealand , and is found on most sub - antarctic islands , as well as on islands south of the antarctic convergence and the antarctic peninsula , south america , and africa .
the southern black - backed gull ( or ‘black - back’ ) is one of the most abundant and familiar large birds in new zealand , although many people do not realise that the mottled brown juveniles ( mistakenly called “mollyhawks” ) are the same species as the immaculate adults . found on or over all non - forested habitats from coastal waters to high - country farms , this is the only large gull found in new zealand . they are particularly abundant at landfills , around ports and at fish - processing plants .
kelp gulls nest on beaches , among rocks , grassy headlands , ledges , glacial moraines and offshore islets . the shapes and materials of the nests vary due to location . they construct bowls or conical mounds or shallow scrapes in sand with grass , seaweed , sticks , shells and debris .
mainly inhabiting coastal regions , the kelp gull can be found in a variety of habitats including harbours , bays , inlets , estuaries , beaches and rocky shores , and usually forages within about ten kilometres of the shore ( 6 ) . it may also venture inland , visiting lakes , lagoons , rivers , streams and reservoirs , as well as pastures , cultivated land , grassland and scrubland . breeding usually takes place on headlands , sea cliffs , beaches , offshore islands , pastures , or even on roofs in urban areas ( 2 ) ( 6 ) .
@ article { bhlpart81344 , title = { taxonomy of the kelp gull larus dominicanus lichtenstein inferred from biometrics and wing plumage pattern , including two previously undescribed subspecies } , journal = { bulletin of the british ornithologists ' club . } , volume = { 122 } , copyright = { in copyright . digitized with the permission of the rights holder . } , url = urltoken publisher = { london : british ornithologists ' club , 1893 - } , author = { } , year = { 2002 } , pages = { 50 - - 71 } , }
“once one gull figures out a fast food meal like cape fur seal eyeballs , other gulls observe and quickly learn the new feeding behavior , ” jewell says . ( also see
cute killers ? gray seals maul , suffocate seals and porpoises , studies say .
)
l . d . dominicus ( here described ) is found on the coasts of s south america and islands such as the falklands and south georgia . but it is also present in new zealand and australia . it is known as southern black - backed gull in new zealand .
kelp gulls are predominantly white birds with a brownish / black wing slate , bright yellow beak with a red spot near the tip and their eyes are dark brown with an orange eye ring . they can grow to 65cm in height , 1kg in weight and have a wing span of 128 - 142cm .
reproduction of this species : the breeding season varies , depending on the range , but usually occurs between september and january . they breed in december in the falklands and at any time on offshore islands . the kelp gull breeds in colonies , from dozens ( at range’s edges ) to several hundreds of pairs . the nest is built on rocks or sand , in well vegetated areas . it is often placed under the protection of rock , bush or tree , or any vertical structure . this is a bulky nest made with dried plants and seaweeds . it is lined with softer vegetation .
similar species : adults unmistakeable apart from possible vagrant pacific gull from australia ( which has a more massive bill , and a black subterminal tip to tail ) . juveniles may be confused with the more robust brown skua , which has broader wings with a pale flash at the base of the primaries .
the diet of the kelp gull ( larus dominicanus ) , its foraging behaviour and the consumption rates on the antarctic limpet ( nacella concinna ) were studied during austral spring and summer 1992 / 1993 and 1993 / 1994 at potter peninsula , king george island , antarctica . prey information was obtained by collecting 237 pellets , foraging behaviour was observed by focal and instantaneous scan samplings , and consumption rate was estimated by means of weekly sampling of limpets found in 5 nests and their respective middens . limpets were the most important prey followed by scavenged prey ( penguin and seal carcasses ) , amphipods , snails , fish and euphausiids . foraging gulls spent 51 % of the time searching for limpets , 10 % moving between foraging areas , 9 % in catching effort and 15 % handling prey . the number of gulls observed searching for limpets was inversely correlated with the tidal height . in the diet limpets provide 102 . 3 , 159 . 4 and 188 . 1 kj gull −1 day −1 during incubation , hatching and brooding respectively ; these values range between 15 and 27 % , with a maximum of 40 % , of the basic daily energy requirements of kelp gulls . total consumption rate estimations for the whole population of gulls at potter peninsula reached between 3400 and 4800 limpets day −1 , which represents approximately 10–14 % of the total annual limpet mortality .
the familiar large gull throughout new zealand . adults have white head and underparts with black back , yellow bill with red spot near tip of lower mandible , and pale green legs . juveniles are dark mottled brown with black bill and legs ; their plumage lightens with age until they moult into adult plumage at 3 years old .
a large black - and - white gull with a white head and underparts , black back , yellow bill with a red spot near the tip , and pale green legs . juveniles are dark mottled brown with black bill and legs ; their plumage lightens with age until they moult into adult plumage at 3 - years - old .
great black - backed gull ( marinus ) adult , 2009 - 2011 , acer port , israel . ( amir ben dov ) . note very large white tips on p10 ( no sub - terminal black ) and on p9 ( black band broken ) and no black on p5 . very powerful , huge massive bill and beady eye .
the kelp gull is resident in the falklands , with some dispersion around the islands . the birds of antarctica ( race “austrinus” ) remain in their range all year round . they can be seen in open water away from the pack ice . in australia , the non - breeding birds disperse to queensland , and along the s coast . the new zealand birds remain in their breeding areas and perform only some n movements . in africa ( race “vetula” ) , the non - breeding gulls move as far as mozambique on e coast , and mauritania and s morocco on w coats . although being largely sedentary , some of the southern populations migrate n outside the breeding season . the flight is powerful , fast and agile , with slow , steady wingbeats .
kelp gulls nest on beaches , among rocks , grassy headlands , ledges and offshore islands . the nest is a bowl of grasses and plants stems or a shallow scrape in sand lined with seaweed , shells and debris . the female usually lays 2 or 3 eggs . both parents feed the young birds . chicks peck at red spot on the parent ' s beak to stimulate the regurgitation reflex .
the adult is a typical gull with black upperparts and white tail . on the black upperwing , the trailing edge is white and the wing tip shows white patches . head , neck , nape , tail and underparts are white . the bill is yellow with red gonydal angle . the eyes are yellow , surrounded by red or orange eyering . legs and webbed feet are greenish - yellow ( mostly greyer in africa ) .
adult gulls and terns are for the most part pale - colored birds plumaged in gray , white , and black with dark plumages predominating in the black tern and noddy species . other colors are limited to orange and yellow ( in the bills and feet ) and pink hues in the plumage of the ross ' s gull and roseate tern . immature gulls of most species cycle through years of a seemingly bewildering number of gray , brown , and black streaked plumages .
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however the problem hasn’t gone away and is specific to the area . it is especially bad because the seagulls target the calves more as they have to spend more time at the surface , so it was quite common to see calves with a lot of scarring along their backs . this leaves the animals prone to infection which can cause death , but it also disturbs the animals when they are taking milk which can mean they don’t get enough and don’t grow as big before it is time to set off to the feeding grounds in antarctica before the summer arrives . scientists have been studying this behaviour for a few years now and it is a complex problem that is not simple to solve and unfortunately man made . not all of the kelp gulls display this behaviour , i witnessed many gulls fly close to whales and simply fly off , but i also witnessed gulls that would arrive to attack the whale , quite often after a while had given up its location by breaching or tail slapping .
seagulls have developed a hunting strategy never before seen in the animal world—eating the eyeballs of live seal pups , a new study says .
since blinded seals can ' t find help from other seals and easily succumb to more attacks , the birds have discovered removing eyeballs is an especially efficient way to get a meal .
the behavior seems to be entirely new to science—if a little tough to stomach , says study lead author austin gallagher , a postdoctoral researcher at carleton university in ottawa , canada . ( also see
gulls be gone : 10 ways to get rid of pesky birds .
)
“it is not a pleasant behavior to observe , as the seals completely freak out and make a lot of noise , ” says gallagher , whose study was published august 14 in the african journal of marine science .
for one , the babies can’t swim and have to rely on their mother’s milk , says michelle jewell , a behavioral ecologist at the royal netherlands institute for sea research who wasn ' t involved in the new research .
to supply that milk , the mother seals must occasionally go hunt fish , leaving the pups alone at the colony for several days . the unprotected pups might then fall prey to land predators such as lions and hyenas—and now , seagulls .
“a blind seal cannot forage , cannot find mom , and will get attacked by other gulls , ” says gallagher . ( also see
baby harp seals being drowned , crushed amid melting ice .
)
a snail will make a nice snack for a seagull , if it can figure out how to crack the shell open .
gallagher believes it ' s likely a result of an increase in cape fur seal populations—essentially , the birds are taking advantage of a newly abundant food source .
in the winter months , between 20 , 000 and 80 , 000 of the pinnipeds flock to namibia’s coasts to mate and raise young . this dramatic population increase from just around a hundred seals in 1998 is due to the species ' natural boom - and - bust cycles , the study says .
not to mention
the eyes are soft targets , and a good source of both fluid and protein , ” adds craig harms , a veterinary medicine expert at north carolina state university who wasn ' t involved in the new research .
as a responder for the u . s . marine mammal health and stranding response program , harms has seen firsthand the damage gulls can do .
“gulls particularly like to peck at and eat the jaw fats of beached harbor porpoises , dead or alive , ” says harms .
and while the seal eye - gobbling behavior is new , harms points to other research that shows seagulls peck at southern right whale calves ' back blubber when they surface to breathe .
“it ' s not surprising ,
he says ,
that they would find a similar source of fresh food that is not good at defending itself .
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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 .
turbott , e . g . 1990 . checklist of the birds of new zealand . ornithological society of new zealand , wellington .
justification : this species has an extremely large range , and hence does not approach the thresholds for vulnerable under the range size criterion ( extent of occurrence < 20 , 000 km2 combined with a declining or fluctuating range size , habitat extent / quality , or population size and a small number of locations or severe fragmentation ) . the population trend appears to be increasing , and hence the species does not approach the thresholds for vulnerable under the population trend criterion ( > 30 % decline over ten years or three generations ) . the population size is extremely large , and hence does not approach the thresholds for vulnerable under the population size criterion ( < 10 , 000 mature individuals with a continuing decline estimated to be > 10 % in ten years or three generations , or with a specified population structure ) . for these reasons the species is evaluated as least concern .