Concavenator corcovatus Ortega, Escaso, Sanz, 2010 (Dinosauria: Carcharodontosauridae) Ejemplar MCCM LH 6666 (holotipo) Cretácico Inferior

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1 Concventor corcovtus Orteg, Escso, Snz, 2010 (Dinosuri: Crchrodontosuride) Ejemplr MCCM LH 6666 (holotipo) Cretácico Inferior (Brremiense). Hce unos125 millones de ños Ls Hoys (L Cierv, Cuenc) El único ejemplr conocido hst l fech del dinosurio crnívoro Concventor corcovtus ( el czdor jorodo de Cuenc ) vivió hce unos 125 millones de ños en el pleohumedl de Ls Hoys. Este fósil represent el ejemplr más completo de un dinosurio crcrodontosurio, ddo que h conservdo l myor prte de su esqueleto e incluso impresiones de l piel. Concventor present dos crcterístics especilmente singulres: un pequeñ joro formd justo por delnte de l cder y el desrrollo de uns estructurs en l piel de los rzos que podrín estr relcionds con ls plums que ctulmente presentn ls ves.

2 Vol Septemer 2010 doi: /nture09181 LETTERS A izrre, humped Crchrodontosuri (Theropod) from the Lower Cretceous of Spin Frncisco Orteg 1, Fernndo Escso 1,2 & José L. Snz 2 Crchrodontosurs were the lrgest predtory dinosurs, nd their erly evolutionry history seems to e more intricte thn ws previously thought. Until recently, crchrodontosurs were restricted to group of lrge theropods inhiting the Lte Cretceous Gondwnn lnd msses 1,2, ut in the lst few yers Lursin evidence 3 5 hs een cusing reevlution of their initil diversifiction 6. Here we descrie n lmost complete nd exquisitely preserved skeleton of medium-sized (roughly six metres long) theropod from the Lower Cretceous series (Brremin stge) Konservt-Lgerstätte of Ls Hoys 7 in Cuenc, Spin. Cldistic nlysis supports the ide tht the new txon Concventor corcovtus is primitive memer of Crchrodontosuri 6, exhiiting two unusul fetures: elongtion of the neurpophyses of two prescrl vertere forming pointed, hump-like structure nd series of smll umps on the uln. We think tht these umps re homologous to quill knos present on some modern irds; the knos re relted to the insertion re of folliculr ligments tht nchor the roots of the flight fethers (remiges) to the rm. We propose tht Concventor hs integumentry folliculr structures inserted on the uln, s in modern irds. Becuse scles do not hve follicles, we consider the structures nchored to the Concventor rms to e non-scle skin ppendges homologous to the fethers of modern irds. If this is true, then the phylogenetic rcket for the presence of non-scle skin structures homologous to fethers in theropod dinosurs would e extended to the Neotetnure, enlrging the scope for explining the origin of fethers in theropods. The recent interprettion of the theropod dinosur Neoventor slerii from the Brremin stge of the Isle of Wight, UK, s sl neoventorid crchrodontosurin 6 seems to relte the erly evolutionry history of this trditionlly Gondwnn group to the Lower Cretceous of Europe. In the sme wy, we descrie n exquisitely preserved skeleton of new crchrodontosurin, Concventor corcovtus gen. et sp. nov., from the Lower Cretceous Konservt- Lgerstätte of Ls Hoys in Cuenc, Spin 7. This fossil represents the most complete individul of crchrodontosurin theropod, nd, to our knowledge, the first one in which direct nd indirect evidence of integumentry structures is reported. Theropod Mrsh, 1881 Allosuroide Mrsh, 1878 Crchrodontosuri Benson, Brustte nd Crrno, 2010 Concventor corcovtus Orteg, Escso nd Snz gen. et sp. nov. Etymology. Concventor from Conc (Ltin), for the Spnish province of Cuenc, nd ventor (Ltin), hunter; corcovtus (Ltin), refers to the hump-like structure formed y the elongtion of two prescrl vertere. Holotype. Specimen MCCM-LH 6666 t Museo de ls Ciencis de Cstill-L Mnch, Cuenc, Spin, nerly complete nd rticulted skeleton (Fig. 1). Horizon nd loclity. Ls Hoys site 7. Clizs de L Huérguin Formtion, Upper Brremin (Lower Cretceous); L Cierv township, Cuenc, Spin. Dignosis. A crchrodontosurin 6 (Fig. 2) hving four recesses, three of them connected, on the nsl ones; lrge, rounded, thickened 1 Grupo de Biologí, Deprtmento de Físic Mtemátic y de Fluidos, Fcultd de Ciencis, Universidd Ncionl de Educción Distnci, Pseo Send del Rey 9, Mdrid, Spin. 2 Unidd de Pleontologí, Deprtmento de Biologí, Fcultd de Ciencis, Universidd Autónom de Mdrid, Cntolnco, Mdrid, Spin. ti fi mt III ul r pu fe 2010 Mcmilln Pulishers Limited. All rights reserved u hu co is sc il l po d11 12sp ofe j mx n 100 cm Figure 1 Holotype of Concventor corcovtus. Specimen MCCM-LH 6666 from the Lower Cretceous series (Brremin stge) of Ls Hoys (Cuenc, Spin)., Photogrph under visile light., Schemtic interprettion of the exposed right side of the skeleton., strglus; ofe, ntoritl fenestr; co, corcoid; d11 12sp, neurl spines of the eleventh nd twelfth dorsl vertere; fe, femur; fi, fiul; hu, humerus; il, ilium; is, ischium; j, jugl; l, lcriml; mt III, third mettrsl; mx, mxill; n, nsl; po, postoritl; pu, puis; r, rdius; sc, scpul; ti, tii; u, ungul phlnx; ul, uln. 203

3 LETTERS NATURE Vol Septemer 2010 Jurssic Cretceous Middle Upper Lower Upper M Cm Sn Con Tur Cen Al Apt Br Hu Vl Ber Tit Kim Oxf Cl Bt Bj Al Coelurosuri Sinrptoride Allosurus Neoventor Aerosteon Megrptor Austrloventor Neoventoride Allosuroide Neotetnure Fukuirptor Eocrchri postoritl row occupying one-third of the orit; tll neurpophyses of the eleventh nd twelfth dorsl vertere (five times the height of the centr); reltively high, crnilly directed neurpophyses of the second nd third cudl vertere; nd smll, thorn-like cudl process t the se of ech neurpophysis of the proximl cudl vertere. In ddition, Concventor presents unique comintion of chrcters: the hevily rugose (wrinkled) dorsl surfce of the nsl one, shred with more derived crchrodontosurids 8 nd elisurids 9 ; the nterior end of the jugl one posterior to the internl ntoritl fenestr; the thick dorsoventrl nterior process of the lcriml one; light rugosity on the lcriml horn; no fenestr on the lcriml one; the nteriormost point of the lterl lmin of the ventrl process in the lcriml situted dorsl to the mid-height of the ventrl process, with distinct rugose ptch on the lterl surfce; no suoritl process on the lcriml one; wek enmel wrinkles on teeth djcent to the crine tht do not extend cross the lil nd lingul tooth surfces, (shred with Tyrnnotitn Concventor Acrocnthosurus Sochilong Crchrodontosuri Tyrnnotitn Crchrodontosurus Mpusurus Gignotosurus Crchrodontosuride Figure 2 Time-clirted reduced consensus of the phylogeny of Neotetnure theropods., Hypotheticl flesh reconstruction of Concventor corcovtus., The phylogeny resulting from prsimony nlysis of the dt mtrix 6 in which Concventor is incorported (see Supplementry Informtion). If poorly represented crchrodontosurin tx re considered, Concventor is locted either s the sister group to the remining Crchrodontosuri or s sl crchrodontosurin, ut on removing the less informtive tx, Concventor stnds unequivoclly s the most sl Crchrodontosuride. Concventor possesses two unmiguous synpomorphies of Crchrodontosuri: deeply concve ilic rticulr surfce on the ischi nd proximomedilly inclined femorl hed. Our nlysis grees with recent hypotheses 6 in considering tht Crchrodontosuri is slly split into Crchrodontosuride nd Neoventoride 6. Two crnil synpomorphies would plce Concventor within Crchrodontosuride: the lcriml-postoritl contct nd lrge curving flnge in the jugl process on the postoritl. M, Mstrichtin; Cm, Cmpnin; Sn, Sntonin; Con, Conicin; Tur, Turonin; Cen, Cenomnin; Al, Alin; Apt, Aptin; Br, Brremin; Hu, Huterivin; Vl, Vlnginin; Ber, Berrisin; Tit, Tithonin; Kim, Kimmeridgin; Oxf, Oxfordin; Cl, Cllovin; Bt, Bthonin; Bj, Bjocin; Al, Alenin Mcmilln Pulishers Limited. All rights reserved nd crchrodontosurines 10 ); no crown recurvture, (shred with crchrodontosurines 10 ); ccessory centrodipophysel lmin on the trnsverse processes of the posterior dorsl vertere, (shred with ryonychines 8 ); the prominent rugose distl tuercle on the ischium (prt of the hip one); quill knos in the posterolterl mrgin of the uln, (shred with derived mnirptorns 11 ); nd the precetulr lde of the ilium hving convex ventrl portion of the crnil edge nd hook-like ventrl process, (shred with tyrnnosurs 12 ). Description. The specimen is emedded into lithogrphic limestone with its right side minly exposed. The surrounding sediment hs multiple impressions tht discourged further preprtion, nd thus some chrcters re not ccessile. The skull (Fig. 3) of Concventor is nerly complete, ut the snout nd the occipitl region re not well preserved. The nterior portion of the ntoritl foss hs one or two mxillry recesses. The lcriml nd dorsl surfce of the nsl one exhiit rugose dorsl mrgin. The nsl one shows four lterl recesses elow its dorsl rim, the posterior ones connected y midline groove. A lrge, rugose nd roust postoritl row overhngs the dorsl rim of the orit, occupying one-third of the oritl height. The ventrl rmus of the postoritl hs reltively lrge, nerly tringulr nd lunt introritl process tht differs from the more distlly plced process of Acrocnthosurus nd crchrodontosurines s well s the smll nd rugose process of Eocrchri 10. The frontl does not prticipte in the orit, s in crchrodontosurids, elisurids nd the lrgest tyrnnosurids. The mxillry teeth re trnsversely compressed. They hve convex mesil nd stright distl crine, with smll denticles. Like Eocrchri, they do not hve high-relief enmel wrinkles, nd thus differ from most other crchrodontosurids 10. There re ten cervicl vertere with pleurocoels in the posterior centr. There re 13 dorsl vertere without pleurocoels, unlike in most tetnurns 8. The length of the neurpophyses of the eleventh nd twelfth dorsl vertere (Fig. 3) exceeds five times the height of the centr. The neurl spines of the scrl nd first cudl vertere re low, elow the dorsl rim of the ilium. Neurl spines of the nterior cudl vertere re reltively tll nd the second to the fifth nterior cudl vertere hve smll, thorn-like nterior nd posterior processes. The nterior process is retined long with the whole ville til, s in Allosurus 13. The left scpulocorcoid is exposed in medil view, nd the right one is exposed in ventrl view. The scpulr lde is long, hving prllel orders nd no distl expnsion, unlike Neoventor 4 nd Acrocnthosurus 1. The forelims re short (42% of the hindlim length). The uln hs prominent olecrnon nd series of low umps plced long posterolterl crest (Fig. 4, ). These umps correspond topogrphiclly to, nd re morphologiclly similr to, fether quill knos, nd we consider them homologous to those present in mny irds (Fig. 4c), s well s in other derived mnirptorns, such s Velocirptor mongoliensis 11. The prtilly exposed right mnus is elongted (65% of the length of the whole forerm). The two exposed mnul clws re short, stout nd proximlly tll. The pelvis is orthopuic. The ilic lde is short nd low. The dorsl portion of the crnil mrgin of the precetulr lde hs concve dorsl contour nd convex ventrl portion in the crnil edge. It lso hs conspicuous hook-like ventrl process, s in tyrnnosurids 12. The ilic rticulr surfce is deeply concve in Concventor. The ischitic process of the ischium hs visile distl oot-like expnsion, s in Neoventor 4, nd unlike derived crchrodontosurids without distl oot, such s Gignotosurus 14 nd Mpusurus 15. The long xis of the femorl hed is less dorsomedilly directed thn in derived crchrodontosurids. The tii is stout nd lrge. The mettrsls re lrge nd roust, contrsting with the smll dimensions of the foot, especilly the pedl unguls. The third mettrsl is the longest; the second nd fourth mettrsls re nerly equl in length. Some delicte integumentry structures re preserved. We interpret some impressions under the pedl digits s remnnts of plntr pds (Fig. 3c), nd the ungul phlnges re ssocited with the impression of corneous sheths. Lrge nd smll integumentry polygonl scles

4 NATURE Vol Septemer 2010 LETTERS 10 cm c o ip plntr pds d mt V 10 cm e 5 cm 1 cm 5 cm f il sp12 sp11 sp10 Figure 3 Detils of the holotype of Concventor corcovtus. Specimen MCCM-LH 6666 from the Lower Cretceous series (Brremin stge) of Ls Hoys (Cuenc, Spin)., Lterl view of the skull., Middle prt of the xil skeleton showing the distriution of the height of the neurl spines of vertere round the pelvic region. c, Detil of distl phlnx of the right foot showing impressions of plntr pds nd corneous sheths of the ungul ones. d, Impressions of hexgonl scles ssocited with the fifth mettrsl. e, Distl portion of the til vertere showing ody outline. f, Distl portion of the til vertere showing ody outline nd the disposition of some rectngulr scles. il, ilium; ip, introritl process; o, oritl row; mt V, fifth mettrsl; sp10 12, neurl spines of the tenth twelfth dorsl vertere. re visile in the mettrsl re of the nkle region (Fig. 3d). An lmost continuous impression delimiting the distl cudl outline is extended oth dorslly nd ventrlly to the verterl series (Fig. 3e). On the ventrl side, the impression of three nerly qudrngulr scles is ssocited with ech verter (Fig. 3f). The scle diversity shown y Concventor is quite similr to tht of some present-dy Neornithes (modern irds), in which reticulte, scutte nd scutell scles re present The former correspond to the footpds. Scutte scles re rectngulr nd re situted on the nterior mettrsl re nd the dorsl digit zone. Scutell scles re plced lterl to the scutte scles; they re smller ut lso rectngulr in outline. Proly the most conspicuous fetures of Concventor re the hypertrophied neurl spines on the eleventh nd twelfth dorsl vertere. Elongted neurpophyses re reltively common in dinosurs ; mong theropods, they re well known in spinosurids, crchrodontosurids nd some undetermined tetnurns However, none of these hs elongted neurpophyses restricted to two prescrl dorsl vertere (Figs 1, 2). The elongted neurpophyses hve een lrgely thought to e support structures for thermoregultion, energy storge or even disply 27, ut the rupt, tll nd crnio-cudlly short singulr structure of Concventor hs no nlogous structures, nd its function is uncler. The presence of ulnr quill knos is lso noteworthy. Ulnr quill knos re structures on the periosteum tht re exclusively relted to folliculr ligments tht nchor the roots of the remiges (flight fethers) to the one. Becuse scles do not hve follicles, we consider the quill knos on the posterolterl side of the Concventor uln (Fig. 4) to indicte the presence of non-scle skin ppendges in similr position to tht of the remiges of modern irds nd, therefore, homologous to them. Recent findings hve reported the presence of filmentous tuulr integumentry structures in ornithischin dinosurs such s the heterodontosurid Tinyulong 28 nd the certopsin Psittcosurus 29. The dete out the homology etween these structures nd ird fethers is open. If ornithischin tuulr filments re kind of fether, they re n evolutionry novelty in dinosurs, nd their presence is expected in non-mnirptorn theropods such s Concventor. If they re not type of fether, Concventor mrks the most primitive presence of non-scle skin ppendges in the theropod linege, plcing them t the node Neotetnure. The simplest hypothesis out the ulnr Concventor skin ppendges is tht they re short, rigid filments (Fig. 2). However, it is possile tht they might hve hd r ridges, ecuse these structures pper efore the formtion of the follicle 18,30. In ny cse, Concventor shows tht the comintion of scle nd non-scle skin ppendges exhiited in present-dy poultry ws lredy present in lrge theropod dinosurs 130 million yers go. c Figure 4 Forerm of Concventor corcovtus. Specimen MCCM-LH 6666 from the Lower Cretceous series (Brremin stge) of Ls Hoys in Cuenc, Spin., Forerm (rdius nd uln) of Concventor corcovtus., Detil of the posterolterl crest showing series of fether quill knos (rrows mrk the ville five elements of the series). c, Dorsl view of the uln of n extnt turkey vulture (Cthrtes sp.). Scle rs, 1 cm. Received 7 April; ccepted 18 My Mcmilln Pulishers Limited. All rights reserved 1. Currie, P. J. & Crpenter, K. A new specimen of Acrocnthosurus tokensis (Theropod, Dinosuri) from the Lower Cretceous Antlers Formtion (Lower Cretceous, Aptin) of Oklhom, USA. Geodiversits 22, (2000). 2. Novs, F. E., de Vlis, S., Vickers-Rich, P. & Rich, T. A lrge Cretceous theropod from Ptgoni, Argentin, nd the evolution of crchrodontosurids. 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