[dinosaur] Crocodylia terrestrial locomotor abilities evolution + Purussaurus axial skeleton (free pdfs)
Ben Creisler <[email protected]> Tue, 17 Dec 2019 08:01:45 -0800
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--00000000000097d5760599e87275 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: Quoted-printable Ben [email protected]=0A=0A=0ANew papers with free pdfs:=0A=0A= =0AJohn R. Hutchinson, Dean Felkler, Kati Houston, Yu-Mei Chang, John=0ABru= eggen, David Kledzik & Kent A. Vliet (2019)=0ADivergent evolution of terre= strial locomotor abilities in extant Crocodylia.=0AScientific Reports 9, Ar= ticle number: 19302=0Adoi: https://urldefense.proofpoint.com/v2/url?u=3Dht= tps-3A__doi.org_10.1038_s41598-2D019-2D55768-2D6&d=3DDwIFaQ&c=3DclK7kQUTWtA= VEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJg= FW9SI&m=3DcgGVIEd-aiOO21ODrrZQSzEsLJP8-pauH1os2QdhkYk&s=3DrKt32XuuK26KnY7lo= 0gG_p_A90UX0WEih7HNxUAhfo4&e=3D=20=0Ahttps://urldefense.proofpoint.com/v2/u= rl?u=3Dhttps-3A__www.nature.com_articles_s41598-2D019-2D55768-2D6&d=3DDwIFa= Q&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZ= gecRCKHn5g4z1CYJgFW9SI&m=3DcgGVIEd-aiOO21ODrrZQSzEsLJP8-pauH1os2QdhkYk&s=3D= QCe54aE-KzYbFI6hHOAgX7VwkoyW-yKdXDbivYQmRxM&e=3D=20=0A=0AFree pdf:=0Ahttps:= //urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.nature.com_articles_s4= 1598-2D019-2D55768-2D6.pdf&d=3DDwIFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8= p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3DcgGVIEd-aiOO= 21ODrrZQSzEsLJP8-pauH1os2QdhkYk&s=3DxFePh4r7peAv9BJ_Evqx_EX34-TF3Nb11h9G8O_= YiMw&e=3D=20=0A=0A=0AExtant Crocodylia are exceptional because they employ = almost the full range=0Aof quadrupedal footfall patterns ("gaits") used by = mammals; including=0Aasymmetrical gaits such as galloping and bounding. Per= haps this capacity=0Aevolved in stem Crocodylomorpha, during the Triassic w= hen taxa were=0Asmaller, terrestrial, and long-legged. However, confusion a= bout which=0ACrocodylia use asymmetrical gaits and why persists, impeding= =0Areconstructions of locomotor evolution. Our experimental gait analysis o= f=0Alocomotor kinematics across 42 individuals from 15 species of Crocodyli= a=0Aobtained 184 data points for a wide velocity range (0.15=E2=80=934.35 m= s=E2=88=921). Our=0Aresults suggest either that asymmetrical gaits are ance= stral for Crocodylia=0Aand lost in the alligator lineage, or that asymmetri= cal gaits evolved=0Awithin Crocodylia at the base of the crocodile line. Re= gardless, we=0Arecorded usage of asymmetrical gaits in 7 species of Crocody= loidea=0A(crocodiles); including novel documentation of these behaviours in= 5=0Aspecies (3 critically endangered). Larger Crocodylia use relatively le= ss=0Aextreme gait kinematics consistent with steeply decreasing athletic ab= ility=0Awith size. We found differences between asymmetrical and symmetrica= l gaits=0Ain Crocodylia: asymmetrical gaits involved greater size-normalize= d stride=0Afrequencies and smaller duty factors (relative ground contact ti= mes),=0Aconsistent with increased mechanical demands. Remarkably, these gai= ts did=0Anot differ in maximal velocities obtained: whether in Alligatoroid= ea or=0ACrocodyloidea, trotting or bounding achieved similar velocities, re= vealing=0Athat the alligator lineage is capable of hitherto unappreciated e= xtreme=0Alocomotor performance despite a lack of asymmetrical gait usage. H= ence=0Aasymmetrical gaits have benefits other than velocity capacity that e= xplain=0Atheir prevalence in Crocodyloidea and absence in Alligatoroidea=E2= =80=94and their=0Abroader evolution.=0A=0A=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=0A=0A=0ATorsten M Scheyer Is a corresponding author, John R Hu= tchinson, Olivier=0AStrauss, Massimo Delfino, Jorge D Carrillo-Brice=C3=B1o= , Rodolfo S=C3=A1nchez &=0AMarcelo R S=C3=A1nchez-Villagra (2019)=0AGiant e= xtinct caiman breaks constraint on the axial skeleton of extant=0Acrocodyli= ans.=0AeLife 8:e49972=0ADOI: 10.7554/eLife.49972=0Ahttps://urldefense.proof= point.com/v2/url?u=3Dhttps-3A__elifesciences.org_articles_49972&d=3DDwIFaQ&= c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZge= cRCKHn5g4z1CYJgFW9SI&m=3DcgGVIEd-aiOO21ODrrZQSzEsLJP8-pauH1os2QdhkYk&s=3D6Q= QsIfy1kASVqr5U2YrnTtM1L5cT_kmuDCQ8C77olDQ&e=3D=20=0A=0A=0AThe number of pre= caudal vertebrae in all extant crocodylians is remarkably=0Aconservative, w= ith nine cervicals, 15 dorsals and two sacrals, a pattern=0Apresent also in= their closest extinct relatives. The consistent vertebral=0Acount indicate= s a tight control of axial patterning by Hox genes during=0Adevelopment. He= re we report on a deviation from this pattern based on an=0Aassociated skel= eton of the giant caimanine Purussaurus, a member of crown=0ACrocodylia, an= d several other specimens from the Neogene of the northern=0Aneotropics. P.= mirandai is the first crown-crocodylian to have three=0Asacrals, two true = sacral vertebrae and one non-pathological and functional=0Adorsosacral, to = articulate with the ilium (pelvis). The giant body size of=0Athis caiman re= lates to locomotory and postural changes. The iliosacral=0Aconfiguration, a= more vertically oriented pectoral girdle, and low torsion=0Aof the femoral= head relative to the condyles are hypothesized=0Aspecializations for more = upright limb orientation or weight support.=0A=0A=3D=3D=0A=0ABlog and news:= =0A=0Ahttps://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__whatsinjohnsfr= eezer.com_2019_12_17_crimbo-2Dcrocodylia_&d=3DDwIFaQ&c=3DclK7kQUTWtAVEOVIgv= i0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m= =3DcgGVIEd-aiOO21ODrrZQSzEsLJP8-pauH1os2QdhkYk&s=3DPzXFhzhD0VCtM0Z4exW5pkuJ= pJSvAnh1e0JbmA1WqDc&e=3D=20=0A=0Ahttps://urldefense.proofpoint.com/v2/url?u= =3Dhttps-3A__www.sciencefocus.com_news_ancient-2D8-2Dmetre-2Dcrocodile-2Dne= eded-2Dextra-2Dbones-2Dto-2Dmove-2Daround_&d=3DDwIFaQ&c=3DclK7kQUTWtAVEOVIg= vi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&= m=3DcgGVIEd-aiOO21ODrrZQSzEsLJP8-pauH1os2QdhkYk&s=3DOy75c2f-U91EROHWRT63DsI= zpZfBF6Tw4sjxqbTNiQs&e=3D=20=0A=0Ahttps://urldefense.proofpoint.com/v2/url?= u=3Dhttps-3A__www.irishnews.com_magazine_science_2019_12_17_news_how-2Ddid-= 2Dgiant-2Dancient-2Dcrocodiles-2Dthrow-2Dtheir-2Dweight-2Daround-2D-2D17930= 32_&d=3DDwIFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IF= aUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3DcgGVIEd-aiOO21ODrrZQSzEsLJP8-pauH1o= s2QdhkYk&s=3DT-lYU9xXSzh0KJq3h83mAxSU7myYSr0NmNPMKxR6gIA&e=3D=20=0A= --00000000000097d5760599e87275 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: Quoted-printable <div dir=3D"ltr"><div><br></div>Ben Creisler<div><a href=3D"mailto:bcreisle= [email protected]">[email protected]</a></div><div><br></div><div><br></div><di= v>New papers with free pdfs:<br><div><br></div><div><br></div><div>John R. = Hutchinson, Dean Felkler, Kati Houston, Yu-Mei Chang, John Brueggen, David = Kledzik & Kent A. Vliet =C2=A0(2019)<br>Divergent evolution of terrestr= ial locomotor abilities in extant Crocodylia.<br>Scientific Reports 9, Arti= cle number: 19302 <br>doi: =C2=A0<a href=3D"https://urldefense.proofpoint.c= om/v2/url?u=3Dhttps-3A__doi.org_10.1038_s41598-2D019-2D55768-2D6&d=3DDw= MFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaU= mGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3DcgGVIEd-aiOO21ODrrZQSzEsLJP8-pauH= 1os2QdhkYk&s=3DrKt32XuuK26KnY7lo0gG_p_A90UX0WEih7HNxUAhfo4&e=3D">ht= tps://doi.org/10.1038/s41598-019-55768-6</a><br><a href=3D"https://urldefen= se.proofpoint.com/v2/url?u=3Dhttps-3A__www.nature.com_articles_s41598-2D019= -2D55768-2D6&d=3DDwMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfn= c_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3DcgGVIEd-ai= OO21ODrrZQSzEsLJP8-pauH1os2QdhkYk&s=3DQCe54aE-KzYbFI6hHOAgX7VwkoyW-yKdX= DbivYQmRxM&e=3D">https://www.nature.com/articles/s41598-019-55768-6</a>= </div><div><br>Free pdf:<br><a href=3D"https://urldefense.proofpoint.com/v2= /url?u=3Dhttps-3A__www.nature.com_articles_s41598-2D019-2D55768-2D6.pdf&= ;d=3DDwMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_= mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3DcgGVIEd-aiOO21ODrrZQSzEsLJ= P8-pauH1os2QdhkYk&s=3DxFePh4r7peAv9BJ_Evqx_EX34-TF3Nb11h9G8O_YiMw&e= =3D">https://www.nature.com/articles/s41598-019-55768-6.pdf</a></div><div><= br><br>Extant Crocodylia are exceptional because they employ almost the ful= l range of quadrupedal footfall patterns ("gaits") used by mammal= s; including asymmetrical gaits such as galloping and bounding. Perhaps thi= s capacity evolved in stem Crocodylomorpha, during the Triassic when taxa w= ere smaller, terrestrial, and long-legged. However, confusion about which C= rocodylia use asymmetrical gaits and why persists, impeding reconstructions= of locomotor evolution. Our experimental gait analysis of locomotor kinema= tics across 42 individuals from 15 species of Crocodylia obtained 184 data = points for a wide velocity range (0.15=E2=80=934.35=E2=80=89ms=E2=88=921). = Our results suggest either that asymmetrical gaits are ancestral for Crocod= ylia and lost in the alligator lineage, or that asymmetrical gaits evolved = within Crocodylia at the base of the crocodile line. Regardless, we recorde= d usage of asymmetrical gaits in 7 species of Crocodyloidea (crocodiles); i= ncluding novel documentation of these behaviours in 5 species (3 critically= endangered). Larger Crocodylia use relatively less extreme gait kinematics= consistent with steeply decreasing athletic ability with size. We found di= fferences between asymmetrical and symmetrical gaits in Crocodylia: asymmet= rical gaits involved greater size-normalized stride frequencies and smaller= duty factors (relative ground contact times), consistent with increased me= chanical demands. Remarkably, these gaits did not differ in maximal velocit= ies obtained: whether in Alligatoroidea or Crocodyloidea, trotting or bound= ing achieved similar velocities, revealing that the alligator lineage is ca= pable of hitherto unappreciated extreme locomotor performance despite a lac= k of asymmetrical gait usage. Hence asymmetrical gaits have benefits other = than velocity capacity that explain their prevalence in Crocodyloidea and a= bsence in Alligatoroidea=E2=80=94and their broader evolution.<br><br>=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<br></div><div><br></div><div><br></= div><div>Torsten M Scheyer Is a corresponding author, John R Hutchinson, Ol= ivier Strauss, Massimo Delfino, Jorge D Carrillo-Brice=C3=B1o, Rodolfo S=C3= =A1nchez & Marcelo R S=C3=A1nchez-Villagra (2019)<br>Giant extinct caim= an breaks constraint on the axial skeleton of extant crocodylians.<br>eLife= 8:e49972 <br>DOI: 10.7554/eLife.49972<br><a href=3D"https://urldefense.pro= ofpoint.com/v2/url?u=3Dhttps-3A__elifesciences.org_articles_49972&d=3DD= wMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFa= UmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3DcgGVIEd-aiOO21ODrrZQSzEsLJP8-pau= H1os2QdhkYk&s=3D6QQsIfy1kASVqr5U2YrnTtM1L5cT_kmuDCQ8C77olDQ&e=3D">h= ttps://elifesciences.org/articles/49972</a></div><div><br><br>The number of= precaudal vertebrae in all extant crocodylians is remarkably conservative,= with nine cervicals, 15 dorsals and two sacrals, a pattern present also in= their closest extinct relatives. The consistent vertebral count indicates = a tight control of axial patterning by Hox genes during development. Here w= e report on a deviation from this pattern based on an associated skeleton o= f the giant caimanine Purussaurus, a member of crown Crocodylia, and severa= l other specimens from the Neogene of the northern neotropics. P. mirandai = is the first crown-crocodylian to have three sacrals, two true sacral verte= brae and one non-pathological and functional dorsosacral, to articulate wit= h the ilium (pelvis). The giant body size of this caiman relates to locomot= ory and postural changes. The iliosacral configuration, a more vertically o= riented pectoral girdle, and low torsion of the femoral head relative to th= e condyles are hypothesized specializations for more upright limb orientati= on or weight support.<br><br>=3D=3D<br></div><div><br></div><div>Blog and n= ews:</div><div><br><a href=3D"https://urldefense.proofpoint.com/v2/url?u=3D= https-3A__whatsinjohnsfreezer.com_2019_12_17_crimbo-2Dcrocodylia_&d=3DD= wMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFa= UmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3DcgGVIEd-aiOO21ODrrZQSzEsLJP8-pau= H1os2QdhkYk&s=3DPzXFhzhD0VCtM0Z4exW5pkuJpJSvAnh1e0JbmA1WqDc&e=3D">h= ttps://whatsinjohnsfreezer.com/2019/12/17/crimbo-crocodylia/</a><br><br><a = href=3D"https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.sciencef= ocus.com_news_ancient-2D8-2Dmetre-2Dcrocodile-2Dneeded-2Dextra-2Dbones-2Dto= -2Dmove-2Daround_&d=3DDwMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p= 7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3DcgGVI= Ed-aiOO21ODrrZQSzEsLJP8-pauH1os2QdhkYk&s=3DOy75c2f-U91EROHWRT63DsIzpZfB= F6Tw4sjxqbTNiQs&e=3D">https://www.sciencefocus.com/news/ancient-8-metre= -crocodile-needed-extra-bones-to-move-around/</a></div><div><br><a href=3D"= https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.irishnews.com_ma= gazine_science_2019_12_17_news_how-2Ddid-2Dgiant-2Dancient-2Dcrocodiles-2Dt= hrow-2Dtheir-2Dweight-2Daround-2D-2D1793032_&d=3DDwMFaQ&c=3DclK7kQU= TWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5= g4z1CYJgFW9SI&m=3DcgGVIEd-aiOO21ODrrZQSzEsLJP8-pauH1os2QdhkYk&s=3DT= -lYU9xXSzh0KJq3h83mAxSU7myYSr0NmNPMKxR6gIA&e=3D">https://www.irishnews.= com/magazine/science/2019/12/17/news/how-did-giant-ancient-crocodiles-throw= -their-weight-around--1793032/</a><br></div></div></div>=0A= --00000000000097d5760599e87275--