[dinosaur] Fin-to-limb transition in tetrapods (free pdf) + bird feathers (free pdf) + Stahleckeria + shape data
Ben Creisler <[email protected]> Mon, 30 Dec 2019 13:39:36 -0800
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--000000000000cb4cea059af2aed0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: Quoted-printable Ben [email protected]=0A=0ASome new non-dino papers:=0A=0A=0AT= homas A. Stewart, Justin B. Lemberg, Natalia K. Taft, Ihna Yoo, Edward B.= =0ADaeschler, and Neil H. Shubin (2019)=0AFin ray patterns at the fin-to-li= mb transition.=0AProceedings of the National Academy of Sciences (advance o= nline publication)=0Adoi: https://urldefense.proofpoint.com/v2/url?u=3Dhttp= s-3A__doi.org_10.1073_pnas.1915983117&d=3DDwIFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU= 5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3Dw= 5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3DmQLu7sVetb8WCiFYOQahjHEFAPrZ= _o18-KR1-RFqSLc&e=3D=20=0Ahttps://urldefense.proofpoint.com/v2/url?u=3Dhttp= s-3A__www.pnas.org_content_early_2019_12_24_1915983117&d=3DDwIFaQ&c=3DclK7k= QUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4= z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3D4wNCLkWFLdi= mk-N6CYAI0F8D49HFR07e_6pRFlZ-ozM&e=3D=20=0A=0AFree pdf:=0Ahttps://urldefens= e.proofpoint.com/v2/url?u=3Dhttps-3A__www.pnas.org_content_pnas_early_2019_= 12_24_1915983117.full.pdf&d=3DDwIFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p= 7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3Dw5IoX9kM39jJo= vU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3Dw49eM01grkjbReW8_bQ9e4BetLkRGxjdiFRw0Ves= JII&e=3D=20=0A=0A=0ASignificance=0A=0ATo explain how limbs evolved from fin= s, paleontologists have traditionally=0Astudied the endoskeleton. Here, we = provide a comparative analysis of the=0Aother skeletal system of fins, the = dermal skeleton. We describe dermal ray=0Aanatomy for 3 species of tetrapod= omorph fishes. These data show that, prior=0Ato the origin of digits, derma= l rays were simplified, the fin web became=0Areduced in size, and the top a= nd bottom of the fin became more asymmetric.=0AThese changes reveal how fin= s became adapted for interacting with the=0Asubstrate prior to the fin-to-l= imb transition and that dorsoventral=0Aasymmetry is an important, understud= ied axis of diversification in paired=0Afins.=0A=0AAbstract=0A=0AThe fin-to= -limb transition was marked by the origin of digits and the loss=0Aof derma= l fin rays. Paleontological research into this transformation has=0Afocused= on the evolution of the endoskeleton, with little attention paid to=0Afin = ray structure and function. To address this knowledge gap, we study the=0Ad= ermal rays of the pectoral fins of 3 key tetrapodomorph taxa=E2=80=94Saurip= terus=0Ataylori (Rhizodontida), Eusthenopteron foordi (Tristichopteridae), = and=0ATiktaalik roseae (Elpistostegalia)=E2=80=94using computed tomography.= These data=0Ashow several trends in the lineage leading to digited forms, = including the=0Aconsolidation of fin rays (e.g., reduced segmentation and b= ranching),=0Areduction of the fin web, and unexpectedly, the evolution of a= symmetry=0Abetween dorsal and ventral hemitrichia. In Eusthenopteron, dorsa= l rays=0Acover the preaxial endoskeleton slightly more than ventral rays. I= n=0ATiktaalik, dorsal rays fully cover the third and fourth mesomeres, whil= e=0Aventral rays are restricted distal to these elements, suggesting the=0A= presence of ventralized musculature at the fin tip analogous to a fleshy=0A= =E2=80=9Cpalm.=E2=80=9D Asymmetry is also observed in cross-sectional areas= of dorsal and=0Aventral rays. Eusthenopteron dorsal rays are slightly larg= er than ventral=0Arays; by contrast, Tiktaalik dorsal rays can be several t= imes larger than=0Aventral rays, and degree of asymmetry appears to be grea= ter at larger=0Asizes. Analysis of extant osteichthyans suggests that cross= -sectional=0Aasymmetry in the dermal rays of paired fins is plesiomorphic t= o crown group=0Aosteichthyans. The evolution of dermal rays in crownward st= em tetrapods=0Areflects adaptation for a fin-supported elevated posture and= resistance to=0Asubstrate-based loading prior to the origin of digits.=0A= =0A***=0A=0ANews:=0A=0AHow fish fins evolved just before the transition to = land=0A=0Ahttps://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__phys.org_n= ews_2019-2D12-2Dfish-2Dfins-2Devolved-2Dtransition.html&d=3DDwIFaQ&c=3DclK7= kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g= 4z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3DBoip0TBX90= kZLH063oVzdN6U6HJ-9bOjDwvQ6p_Nvc0&e=3D=20=0A=0A=3D=3D=3D=0A=0AFree pdf:=0A= =0AJing-Shan Zhao, Jiayue Zhang, Yuping Zhao, Zhaodong Zhang & Pascal=0AGo= defroit (2020)=0AShaking the wings and preening feathers with the beak help= a bird to=0Arecover its ruffled feather vane.=0AMaterials & Design 187: 10= 8410=0Ahttps://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__doi.org_10.10= 16_j.matdes.2019.108410&d=3DDwIFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7C= Sfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU= 6Dr5p00192cAYSmewXHw9bfNnRr4&s=3DKwfRqRzSdf0viYFue9ZfpXWCEnKhXIxs4DtAy1iI7d= 8&e=3D=20=0Ahttps://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.scie= ncedirect.com_science_article_pii_S0264127519308482&d=3DDwIFaQ&c=3DclK7kQUT= WtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1C= YJgFW9SI&m=3Dw5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3DxeQjcdUGv9EKlX= UH59xUSqBfw6sHyiYN6Al40Y5vih4&e=3D=20=0A=0AHighlights=0A=0AThere is some sp= ace between the hierarchical structures of barbs and=0Abarbules.=0AThe spac= e allows the separated micro-hooklets to recover and interlock.=0AShaking w= ings and preening feathers render deflections on rachis, barbs and=0Abarbul= es.=0ADeformations of rachis, barbs and barbules provide the energy for van= e=0Aself-healing.=0A=0AAbstract=0A=0AThe feather of a bird consists of barb= s which again comprise numerous=0Abarbules with micro-hooklets. This hierar= chically organized feather=0Astructure provides a smooth vane to bear the l= oad from the airflow;=0Ahowever, the feather vane is vulnerable to disrupti= on by external pulling=0Aforces during collision with the branches of a tre= e and hitting some small=0Aobstacles in flight or strong turbulence. The fe= ather is unable to carry=0Athe weight of the bird's body if the vane could = not be recovered=0Aimmediately. Here we discovered that the feather vane ca= n be re-established=0Aeasily by birds themselves. A bird can always recover= its feather vane from=0Aruffled state by shaking its wings and preening it= s feathers with its beak=0Abecause of the cascaded geometries of barbs and = barbules. This biophysical=0Amechanism of self-healing suggests that the hi= erarchical vane structure can=0Abe used to design artificial feathers for a= flapping robot.=0A=0A=3D=3D=3D=0A=0APaywalled:=0A=0AAdriana C. Mancuso & R= andall B. Irmis (2019)=0AThe large-bodied dicynodont Stahleckeria (Synapsid= a, Anomodontia) from the=0AUpper Triassic (Carnian) Cha=C3=B1ares Formation= (Argentina); new data for=0ATriassic Gondwanan biogeography.=0AAmeghiniana= (advance online publication)=0Adoi: 10.5710/AMGH.20.12.2019.3302=0Ahttps:/= /urldefense.proofpoint.com/v2/url?u=3Dhttp-3A__www.ameghiniana.org.ar_index= .php_ameghiniana_article_view_1005&d=3DDwIFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BO= UHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3Dw5Io= X9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3DuS4rU9VNqSs7eygZHnQAhtNCLXX-Gs9= QLgtsvWkBym8&e=3D=20=0A=0A=0AThe non-marine Triassic displays distinct regi= onal differences in tetrapod=0Afossil assemblages even in adjacent regions,= and these patterns have been=0Ahypothesized to reflect provincialism. For = example, in the "Middle=0ATriassic" of Gondwana, the R=C3=ADo Seco de la Qu= ebrada Formation (Puesto Viejo=0AGroup) in western Argentina shares a numbe= r of taxa with the Cynognathus AZ=0Aof the Burgersdorp Formation (Karoo Bas= in) in South Africa. In contrast,=0Athe nearly Cha=C3=B1ares Formation of n= orthwestern Argentina is compositionally=0Adistinct and shows more affiniti= es with the Dinodontosaurus AZ of the lower=0ASanta Maria Formation in sout= hern Brazil and the top of the upper Omingonde=0AFormation of Namibia. Thes= e problems are exacerbated by recent=0Aradioisotopic dates from the Cha=C3= =B1ares Formation and the Puesto Viejo Group=0Asuggest these units are actu= ally Carnian in age. We provide new data for=0Athe biostratigraphy and biog= eography of these units in the form of the=0Afirst record of a stahleckerii= ne dicynodont from the Cha=C3=B1ares Formation, an=0Aulna referable to Stah= leckeria von Huene, 1935. This new occurrence=0Astrengthens the correlation= between Cha=C3=B1ares, Santa Maria, and the top of=0AOmingonde units but r= einforces the differences with the R=C3=ADo Seco de la=0AQuebrada and Burge= rsdorp units. Hypotheses for this provincialism include=0Aassemblages of di= fferent ages, distinct environments controlled by=0Apaleolatitude or paleot= opography between basins that formed a barrier to=0Afaunal interchange.=0A= =0A=3D=3D=3D=3D=0A=0A=0AAlso, free pdf:=0A=0ASilvia Castiglione, Carmela Se= rio, Davide Tamagnini, Marina Melchionna,=0AAlessandro Mondanaro, Mirko Di = Febbraro, Antonio Profico, Paolo Piras,=0AFilippo Barattolo & Pasquale Raia= (2019)=0AA new, fast method to search for morphological convergence with s= hape data.=0APLoS ONE 14(12): e0226949.=0Adoi: https://urldefense.proofpoi= nt.com/v2/url?u=3Dhttps-3A__doi.org_10.1371_journal.pone.0226949&d=3DDwIFaQ= &c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZg= ecRCKHn5g4z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3DM= SqWYRGmY6NMHjU8SH8ooMR7aUsbTmhaBCgXSkpKjOw&e=3D=20=0Ahttps://urldefense.pro= ofpoint.com/v2/url?u=3Dhttps-3A__journals.plos.org_plosone_article-3Fid-3D1= 0.1371_journal.pone.0226949&d=3DDwIFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H= 8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3Dw5IoX9kM39j= JovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3DqpGo7BrGZavj2jVtB12mh8Ek8HYmekKuQC0Ow2= D3-28&e=3D=20=0A=0AFree pdf:=0Ahttps://urldefense.proofpoint.com/v2/url?u= =3Dhttps-3A__journals.plos.org_plosone_article_file-3Fid-3D10.1371_journal.= pone.0226949-26type-3Dprintable&d=3DDwIFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHh= pN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3Dw5IoX9k= M39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3Dp9Sc5ozREgknv0avK1OekM82ToYlnS46_F= 9ZEKZHxh0&e=3D=20=0A=0A=0AMorphological convergence is an intensely studied= macroevolutionary=0Aphenomenon. It refers to the morphological resemblance= between=0Aphylogenetically distant taxa. Currently available methods to ex= plore=0Aevolutionary convergence either: rely on the analysis of the phenot= ypic=0Aresemblance between sister clades as compared to their ancestor, fit= =0Adifferent evolutionary regimes to different parts of the tree to see=0Aw= hether the same regime explains phenotypic evolution in phylogenetically=0A= distant clades, or assess deviations from the congruence between=0Aphylogen= etic and phenotypic distances. We introduce a new test for=0Amorphological = convergence working directly with non-ultrametric (i.e.=0Apaleontological) = as well as ultrametric phylogenies and multivariate data.=0AThe method (dev= eloped as the function search.conv within the R package=0ARRphylo) tests wh= ether unrelated clades are morphologically more similar to=0Aeach other tha= n expected by their phylogenetic distance. It additionally=0Apermits using = known phenotypes as the most recent common ancestors of=0Aclades, taking fu= ll advantage of fossil information. We assessed the power=0Aof search.conv = and the incidence of false positives by means of=0Asimulations, and then ap= plied it to three well-known and long-discussed=0Acases of (purported) morp= hological convergence: the evolution of grazing=0Aadaptation in the mandibl= e of ungulates with high-crowned molars, the=0Aevolution of mandibular shap= e in sabertooth cats, and the evolution of=0Adiscrete ecomorphs among anole= s of Caribbean islands. The search.conv=0Amethod was found to be powerful, = correctly identifying simulated cases of=0Aconvergent morphological evoluti= on in 95% of the cases. Type I error rate=0Ais as low as 4=E2=80=936%. We f= ound search.conv is some three orders of magnitude=0Afaster than a competin= g method for testing convergence.=0A= --000000000000cb4cea059af2aed0 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>Some new non-= dino papers:<br><div><br></div><div><br></div><div>Thomas A. Stewart, Justi= n B. Lemberg, Natalia K. Taft, Ihna Yoo, Edward B. Daeschler, and Neil H. S= hubin (2019)<br>Fin ray patterns at the fin-to-limb transition.<br>Proceedi= ngs of the National Academy of Sciences (advance online publication)<br>doi= : <a href=3D"https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__doi.org= _10.1073_pnas.1915983117&d=3DDwMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUH= hpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m= =3Dw5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3DmQLu7sVetb8WCiFYOQah= jHEFAPrZ_o18-KR1-RFqSLc&e=3D">https://doi.org/10.1073/pnas.1915983117</= a><br><a href=3D"https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www= .pnas.org_content_early_2019_12_24_1915983117&d=3DDwMFaQ&c=3DclK7kQ= UTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn= 5g4z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3D= 4wNCLkWFLdimk-N6CYAI0F8D49HFR07e_6pRFlZ-ozM&e=3D">https://www.pnas.org/= content/early/2019/12/24/1915983117</a></div><div><br>Free pdf:<br><a href= =3D"https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.pnas.org_con= tent_pnas_early_2019_12_24_1915983117.full.pdf&d=3DDwMFaQ&c=3DclK7k= QUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKH= n5g4z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s= =3Dw49eM01grkjbReW8_bQ9e4BetLkRGxjdiFRw0VesJII&e=3D">https://www.pnas.o= rg/content/pnas/early/2019/12/24/1915983117.full.pdf</a></div><div><br><br>= Significance</div><div><br>To explain how limbs evolved from fins, paleonto= logists have traditionally studied the endoskeleton. Here, we provide a com= parative analysis of the other skeletal system of fins, the dermal skeleton= . We describe dermal ray anatomy for 3 species of tetrapodomorph fishes. Th= ese data show that, prior to the origin of digits, dermal rays were simplif= ied, the fin web became reduced in size, and the top and bottom of the fin = became more asymmetric. These changes reveal how fins became adapted for in= teracting with the substrate prior to the fin-to-limb transition and that d= orsoventral asymmetry is an important, understudied axis of diversification= in paired fins.<br><br>Abstract</div><div><br>The fin-to-limb transition w= as marked by the origin of digits and the loss of dermal fin rays. Paleonto= logical research into this transformation has focused on the evolution of t= he endoskeleton, with little attention paid to fin ray structure and functi= on. To address this knowledge gap, we study the dermal rays of the pectoral= fins of 3 key tetrapodomorph taxa=E2=80=94Sauripterus taylori (Rhizodontid= a), Eusthenopteron foordi (Tristichopteridae), and Tiktaalik roseae (Elpist= ostegalia)=E2=80=94using computed tomography. These data show several trend= s in the lineage leading to digited forms, including the consolidation of f= in rays (e.g., reduced segmentation and branching), reduction of the fin we= b, and unexpectedly, the evolution of asymmetry between dorsal and ventral = hemitrichia. In Eusthenopteron, dorsal rays cover the preaxial endoskeleton= slightly more than ventral rays. In Tiktaalik, dorsal rays fully cover the= third and fourth mesomeres, while ventral rays are restricted distal to th= ese elements, suggesting the presence of ventralized musculature at the fin= tip analogous to a fleshy =E2=80=9Cpalm.=E2=80=9D Asymmetry is also observ= ed in cross-sectional areas of dorsal and ventral rays. Eusthenopteron dors= al rays are slightly larger than ventral rays; by contrast, Tiktaalik dorsa= l rays can be several times larger than ventral rays, and degree of asymmet= ry appears to be greater at larger sizes. Analysis of extant osteichthyans = suggests that cross-sectional asymmetry in the dermal rays of paired fins i= s plesiomorphic to crown group osteichthyans. The evolution of dermal rays = in crownward stem tetrapods reflects adaptation for a fin-supported elevate= d posture and resistance to substrate-based loading prior to the origin of = digits.<br></div></div><div><br></div><div>***</div><div><br></div><div>New= s:</div><div><br></div><div>How fish fins evolved just before the transitio= n to land</div><div><br><a href=3D"https://urldefense.proofpoint.com/v2/url= ?u=3Dhttps-3A__phys.org_news_2019-2D12-2Dfish-2Dfins-2Devolved-2Dtransition= .html&d=3DDwMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&am= p;r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU6D= r5p00192cAYSmewXHw9bfNnRr4&s=3DBoip0TBX90kZLH063oVzdN6U6HJ-9bOjDwvQ6p_N= vc0&e=3D">https://phys.org/news/2019-12-fish-fins-evolved-transition.ht= ml</a><br></div><div><br></div><div>=3D=3D=3D</div><div><br></div><div>Free= pdf:</div><div><br></div><div>Jing-Shan Zhao, =C2=A0Jiayue Zhang, Yuping Z= hao, Zhaodong Zhang & Pascal Godefroit (2020)<br>Shaking the wings and = preening feathers with the beak help a bird to recover its ruffled feather = vane.<br>Materials & Design 187: 108410<br><a href=3D"https://urldefens= e.proofpoint.com/v2/url?u=3Dhttps-3A__doi.org_10.1016_j.matdes.2019.108410&= amp;d=3DDwMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3D= Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU6Dr5p001= 92cAYSmewXHw9bfNnRr4&s=3DKwfRqRzSdf0viYFue9ZfpXWCEnKhXIxs4DtAy1iI7d8&am= p;e=3D">https://doi.org/10.1016/j.matdes.2019.108410</a> <br><a href=3D"htt= ps://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.sciencedirect.com_s= cience_article_pii_S0264127519308482&d=3DDwMFaQ&c=3DclK7kQUTWtAVEOV= Igvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJg= FW9SI&m=3Dw5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3DxeQjcdUGv= 9EKlXUH59xUSqBfw6sHyiYN6Al40Y5vih4&e=3D">https://www.sciencedirect.com/= science/article/pii/S0264127519308482</a></div><div><br></div><div>Highligh= ts</div><div><br>There is some space between the hierarchical structures of= barbs and barbules.<br>The space allows the separated micro-hooklets to re= cover and interlock.<br>Shaking wings and preening feathers render deflecti= ons on rachis, barbs and barbules.<br>Deformations of rachis, barbs and bar= bules provide the energy for vane self-healing.</div><div><br>Abstract</div= ><div><br>The feather of a bird consists of barbs which again comprise nume= rous barbules with micro-hooklets. This hierarchically organized feather st= ructure provides a smooth vane to bear the load from the airflow; however, = the feather vane is vulnerable to disruption by external pulling forces dur= ing collision with the branches of a tree and hitting some small obstacles = in flight or strong turbulence. The feather is unable to carry the weight o= f the bird's body if the vane could not be recovered immediately. Here = we discovered that the feather vane can be re-established easily by birds t= hemselves. A bird can always recover its feather vane from ruffled state by= shaking its wings and preening its feathers with its beak because of the c= ascaded geometries of barbs and barbules. This biophysical mechanism of sel= f-healing suggests that the hierarchical vane structure can be used to desi= gn artificial feathers for a flapping robot.<br></div><div><br></div><div>= =3D=3D=3D</div><div><br></div><div>Paywalled:</div><div><br></div><div>Adri= ana C. Mancuso & Randall B. Irmis (2019)<br>The large-bodied dicynodont= Stahleckeria (Synapsida, Anomodontia) from the Upper Triassic (Carnian) Ch= a=C3=B1ares Formation (Argentina); new data for Triassic Gondwanan biogeogr= aphy.<br>Ameghiniana (advance online publication)<br>doi: 10.5710/AMGH.20.1= 2.2019.3302<br><a href=3D"https://urldefense.proofpoint.com/v2/url?u=3Dhttp= -3A__www.ameghiniana.org.ar_index.php_ameghiniana_article_view_1005&d= =3DDwMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO= 4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU6Dr5p00192cAY= SmewXHw9bfNnRr4&s=3DuS4rU9VNqSs7eygZHnQAhtNCLXX-Gs9QLgtsvWkBym8&e= =3D">http://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/1005<= /a><br><br><br>The non-marine Triassic displays distinct regional differenc= es in tetrapod fossil assemblages even in adjacent regions, and these patte= rns have been hypothesized to reflect provincialism. For example, in the &q= uot;Middle Triassic" of Gondwana, the R=C3=ADo Seco de la Quebrada For= mation (Puesto Viejo Group) in western Argentina shares a number of taxa wi= th the Cynognathus AZ of the Burgersdorp Formation (Karoo Basin) in South A= frica. In contrast, the nearly Cha=C3=B1ares Formation of northwestern Arge= ntina is compositionally distinct and shows more affinities with the Dinodo= ntosaurus AZ of the lower Santa Maria Formation in southern Brazil and the = top of the upper Omingonde Formation of Namibia. These problems are exacerb= ated by recent radioisotopic dates from the Cha=C3=B1ares Formation and the= Puesto Viejo Group suggest these units are actually Carnian in age. We pro= vide new data for the biostratigraphy and biogeography of these units in th= e form of the first record of a stahleckeriine dicynodont from the Cha=C3= =B1ares Formation, an ulna referable to Stahleckeria von Huene, 1935. This = new occurrence strengthens the correlation between Cha=C3=B1ares, Santa Mar= ia, and the top of Omingonde units but reinforces the differences with the = R=C3=ADo Seco de la Quebrada and Burgersdorp units. Hypotheses for this pro= vincialism include assemblages of different ages, distinct environments con= trolled by paleolatitude or paleotopography between basins that formed a ba= rrier to faunal interchange.<br><br>=3D=3D=3D=3D<br></div><div><br></div><d= iv><br></div><div>Also, free pdf:</div><div><br></div><div>Silvia Castiglio= ne, Carmela Serio, Davide Tamagnini, Marina Melchionna, Alessandro Mondanar= o, Mirko Di Febbraro, Antonio Profico, Paolo Piras, Filippo Barattolo &= Pasquale Raia (2019)<br>A new, fast method to search for morphological con= vergence with shape data.<br>PLoS ONE 14(12): e0226949.<br>doi: =C2=A0<a hr= ef=3D"https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__doi.org_10.137= 1_journal.pone.0226949&d=3DDwMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhp= N0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3D= w5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s=3DMSqWYRGmY6NMHjU8SH8ooMR= 7aUsbTmhaBCgXSkpKjOw&e=3D">https://doi.org/10.1371/journal.pone.0226949= </a><br><a href=3D"https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__j= ournals.plos.org_plosone_article-3Fid-3D10.1371_journal.pone.0226949&d= =3DDwMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO= 4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU6Dr5p00192cAY= SmewXHw9bfNnRr4&s=3DqpGo7BrGZavj2jVtB12mh8Ek8HYmekKuQC0Ow2D3-28&e= =3D">https://journals.plos.org/plosone/article?id=3D10.1371/journal.pone.02= 26949</a></div><div><br>Free pdf:<br><a href=3D"https://urldefense.proofpoi= nt.com/v2/url?u=3Dhttps-3A__journals.plos.org_plosone_article_file-3Fid-3D1= 0.1371_journal.pone.0226949-26type-3Dprintable&d=3DDwMFaQ&c=3DclK7k= QUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKH= n5g4z1CYJgFW9SI&m=3Dw5IoX9kM39jJovU6Dr5p00192cAYSmewXHw9bfNnRr4&s= =3Dp9Sc5ozREgknv0avK1OekM82ToYlnS46_F9ZEKZHxh0&e=3D">https://journals.p= los.org/plosone/article/file?id=3D10.1371/journal.pone.0226949&type=3Dp= rintable</a><br><br><br>Morphological convergence is an intensely studied m= acroevolutionary phenomenon. It refers to the morphological resemblance bet= ween phylogenetically distant taxa. Currently available methods to explore = evolutionary convergence either: rely on the analysis of the phenotypic res= emblance between sister clades as compared to their ancestor, fit different= evolutionary regimes to different parts of the tree to see whether the sam= e regime explains phenotypic evolution in phylogenetically distant clades, = or assess deviations from the congruence between phylogenetic and phenotypi= c distances. We introduce a new test for morphological convergence working = directly with non-ultrametric (i.e. paleontological) as well as ultrametric= phylogenies and multivariate data. The method (developed as the function s= earch.conv within the R package RRphylo) tests whether unrelated clades are= morphologically more similar to each other than expected by their phylogen= etic distance. It additionally permits using known phenotypes as the most r= ecent common ancestors of clades, taking full advantage of fossil informati= on. We assessed the power of search.conv and the incidence of false positiv= es by means of simulations, and then applied it to three well-known and lon= g-discussed cases of (purported) morphological convergence: the evolution o= f grazing adaptation in the mandible of ungulates with high-crowned molars,= the evolution of mandibular shape in sabertooth cats, and the evolution of= discrete ecomorphs among anoles of Caribbean islands. The search.conv meth= od was found to be powerful, correctly identifying simulated cases of conve= rgent morphological evolution in 95% of the cases. Type I error rate is as = low as 4=E2=80=936%. We found search.conv is some three orders of magnitude= faster than a competing method for testing convergence.<br></div></div>=0A= --000000000000cb4cea059af2aed0--