Boletín de la Sociedad Geológica Mexicana ISSN: 1405-3322 Sociedad Geológica Mexicana, A.C.

Rodríguez-de la Rosa, Rubén A.; Velasco-de León, María Patricia; Arellano-Gil, Javier; Lozano-Carmona, Diego Enrique Middle Jurassic ankylosaur tracks from Mexico Boletín de la Sociedad Geológica Mexicana, vol. 70, no. 2, 2018, May-August, pp. 379-395 Sociedad Geológica Mexicana, A.C.

DOI: https://doi.org/10.18268/BSGM2018v70n2a8

Available in: https://www.redalyc.org/articulo.oa?id=94362562009

How to cite Complete issue Scientific Information System Redalyc More information about this article Network of Scientific Journals from Latin America and the Caribbean, Spain and Journal's webpage in redalyc.org Portugal Project academic non-profit, developed under the open access initiative http://dx.doi.org/10.18268/BSGM2018v70n2a8 P. 379‒395 VOL. 70NO. 2 BOL. SOC.GEOL.MEX.2018 CDMX, Mexico. Ciudad Universitaria, Coyoacán C.P. 04510, Autónoma deMéxico, Av. Universidad 3000, Facultad deIngeniería,Universidad Nacional Javier Arellano-Gil lapa, C.P. 09230,CDMX,Mexico. Fuerte deLoreto, Ejército deOriente, Iztapa Campus II,Batalla 5demayo s/nesquina Universidad NacionalAutónoma deMéxico, Facultad deEstudiosSuperiores Zaragoza, Diego EnriqueLozano-Carmona María Patricia Velasco-de León s/n, C.P. 98060,Zacatecas, Mexico. II, CalzadaSolidaridad,esq.Paseo delaBufa Universidad Autónoma de Zacatecas, Campus Unidad AcadémicadeCienciaslaTierra, Unidad AcadémicadeCienciasBiológicas, [email protected] Rubén A.Rodríguez-de laRosa Diego Enrique Rubén A. Middle JurassicankylosaurtracksfromMexico Manuscript accepted: September 29,2017. Manuscript September accepted: Corrected manuscript received: July 19,2017. Manuscript received: March 21,2017. Rodríguez-de laRosa Lozano-Carmona - , MaríaPatricia Jurassic, Oaxaca, Mexico. podosaurus Keywords: Ankylosauria, known todate. represent the oldest ankylosaurian ichnofossils With their Middle Jurassicage, these footprints North America during Middle Jurassic times. to southern theAnkylosauria the recordin of In thisway, a geographic it suggests ichnogenus the recordMexico of andthe southernmost tracks from ankylosaurian the reportsecond of Jurassic to Early Cretaceous times. It represents ilar paleoecologicalfrom conditions Middle wereAmerican Ankylosauria adapted to sim facies, thussuggesting, that at least the North concentrated in coal-bearing and floodplain record,the global footprints ankylosaur are Formation after is a coal-bearing formation; manus. Zorrillo-Taberna The Indiferenciadas the ankylosaurian the functional mechanicsof well-developed palmar pad, and could suggest a the presence of concavity are indicative of however,features some sucha medio-lateralas thathand morphology; fittheankylosaurian isolatedAn the handprint,has same features preserved tracks,additional ankylosaurian were found whence this block came was identified and two to beatail drag. unitfrom stratigraphic The with these footprints is herein interpreted digits. Acurved structure preserved together impressionpentadactyl,is withshortandblunt were impressed deeply inthe sediment. Manus ventrally curved toe tips, that suggesting these liefs. pesimpressiontetradactyl,is The with are tracks These preserved asconvex hypore preserved onarockblock from thisformation. ( affinity ankylosaurian set of (Bajocian) age. Awell-preserved manus-pes Middle Jurassic Indiferenciadas Formation, of the Zorrillo-Taberna sequence of stratigraphic theropod it is located dinosaurs; within the sauropod and preserves the footprints of Mexico, Oaxaca, southern northwestern Tlaxiaco, River, theÑumí neartheCityof of the shores A track-bearing locality inoneof ABSTRACT in situ Tetrapodosaurus , Ichnology,, Middle Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín Velasco-de León asnatural sandstone casts. inNorth America. Tetrapodosaurus continuum Tetra , Javier ) is - -

Arellano-Gil la Formación Zorrillo-Taberna Indiferenciadas, de de se localiza dentro de la secuencia estratigráfica huellas de dinosaurios saurópodos y terópodos; esta noroeste de Oaxaca, al sur de México, las conserva Río Ñumíenlas cercanías de la Ciudad de Tlaxiaco, Una localidad icnofosilífera enunade las orillas del RESUMEN sico Medio, Oaxaca,México. Tetrapodosaurus Palabras clave: Ankylosauria, anquilosaurios conocidos hasta este momento. Medio. Además, son los icnofósiles más antiguos de hasta elsur de Norte América durante elJurásico continuum nero anquilosauriosMéxico, en yelmás sureño del icnogé de huellas de reporte Este trabajo representa elsegundo lares, desde el Jurásico Medio al Cretácico Temprano. a condicionespaleoecológicas simi estabanadaptados norteamericanos que al menos los Ankylosauria facies aluviales y portadoras de carbón, esto sugiere tarias las huellas de anquilosaurios se concentran en con estratos de carbón; enotras secuencias sedimen Zorrillo-Taberna Indiferenciadas esunaformación funcional de la mano anquilosauriana. La Formación presencia de uncojinete, ypodría sugerir la mecánica cavidad medio lateral de la zona palmar indica la sin embargo, algunas características como la con caracteres morfológicos de la mano anquilosauriana; aislada; éste presenta los mismos encontrado de forma rales de arenisca.relleno Un natural de unamanofue encontradas y dos huellas adicionales de anquilosaurios fueron del bloque portador de las huellas, fue identificado de cola. Elestrato original dearrastre procedenciaun vada juntoa las huellas, es interpretada aquí como conser pequeños y romos. curvada, Unaestructura en elsedimento. La mano es pentadáctila, condedos sugiriendo que éstas fueron impresas profundamente ventralmente, con las puntas de los dedos curvadas convexos. Elpie estetradáctilo,como hiporrelieves las huellas seencuentranconservadas esta formación; ( de pie-manoconjunto de afinidad anquilosauriana edad Jurásico Medio (Bajociano). Seidentificóun Tetrapodosaurus Tetrapodosaurus geográfico en el registro de Ankylosauria, de Ankylosauria, enelregistro geográfico in

situ ) enunbloque de roca procedente de , conservadas como rellenos natu , conservadas enNorte América; sugiriendo un , , Icnología, Jurá /2018 379 ------

Middle Jurassic ankylosaur tracks from Mexico ABSTRACT INTRODUCTION / GEOLOGICAL Middle Jurassic ankylosaur tracks from Mexico SETTING 380 380 1. Introduction ern ern Oaxaca, in southern Mexico (figures 1, 2).The Tlaxiaco, northwestÑumí River, near the City of found alocality bearing dinosaur footprints in the for (MPVL) the authors paleobotanical sites, search oneof in fieldwork paleontological During thermore,tracks are the ankylosaur referred to as mentioned as other in their specimens work.Fur the specimen isavailable or lost in Mexico, orif the illustratedfoundwas specimens whichone of the tracks, and do not specify outline drawings of However, present these authors only illustrated Ciudad Juárez, Mexico. Chihuahua,northern ankylosaur tracksnear mentions the presence of tellano-Ballesteros, 2011).Kappus vera-Sylva (Rivera-Sylva andEspinosa-Chávez, 2006;Ri and afewlimbelements have also been found anisolatedco are vertebra, teeth and osteoderms, remainsankylosaur most common found inMexi Chihuahua and Coahuila. Among the California, Mexico, states mainly from such asBaja northern remainsAnkylosaurian have been collected in anankylosauriandinosaur. manus-pes setof derside. these Among tracks isawell-preserved saur tracks, preserved as natural casts initsun track-bearing surface (Figure 4) contained dino the main noted that afallen rockblock in front of it was however, season; field consecutive a in ed thisdinosaurtracksite start studyof 2016). The al. Velasco-de León (Silva-Pineda Equisetales, Filicales, and Ginkgoales conifers Bennettitales, Caytoniales, fossilplants of cord of preservesgeological formation This anotable re 1989; Corro-Ortiz and Ruíz-González, 2011). age (Carrasco-Ramírez, 1981; González-Torres, MiddleJurassic na IndiferenciadasFormation, of the Zorrillo-Taber sequenceof the stratigraphic dríguez-de la Rosa na, 2012;Rodríguez-de la Rosa,2014, 2015;Ro (Lozano-Carmo 4) 3, (figures theropoddinosaurs sauropod and locality preserves the footprints of / , 2015; Lozano-Carmona andVelasco-de, 2015; Lozano-Carmona León, Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín et al. et al. , 2011;Martínez-Díaz andMon , 2007; Lozano-Carmona, 2012; , 2007;Lozano-Carmona, et al. et al. , 2013;Velasco-de León , 2014);it is located within et al. (2011) et ------/2018 2. Geologicalsetting Caltepec lateralCaltepec fault (Sedlock rez,contact alongthe in 2006);bothterrains (Dávalos-Álva Zapoteco and Mixtecoterrains which between isplaced inthe boundary the studyareaThe located is Basin, in theTlaxiaco an ichnofossils known todate. Jurassic age, they represent the oldest ankylosauri report these tracks, noting that due to their Middle paper to this is istent. Therefore, of thepurpose pus “ prints belongs to the Zorrillo-Taberna Indiferen rockThe block containingthe ankylosaurian foot 1965). limestones (Pérez-Ibargüengoitiaplatform carbonate marine origin, composedof mation of area is the Albian-Cenomanian Teposcolula For only post-Jurassic outcropping formation in the Oxfordian age (Carrasco-Ramírez, 1981).The Caliza con tocorresponds amarine environment unitnamed youngestThe Jurassic unit outcropping inthe area the Otatera and Yucuñuti (Figure 5). formations Simón formations, andanupperunitcomprising prising the Zorrillo-Taberna Indiferenciadas and ca Group into two subgroups: alower unit com González-Torres (1989)dividedthe Tecocoyun Otatera, and Yucuñuti formations. Subsequently, rillo-Taberna IndiferanciadasFormation, Simón, that, order in ascendingstratigraphic are, the Zor four formations coyuncaGroup of composed is According to Carrasco-Ramírez (1981) the Teco and Velasco-de Lozano-Carmona León, 2016). (Erben, 1956; Sandoval and Westermann, 1986; age that ranges from the Bajocian to Callovian unit overlying the Ñumí Conglomerate, withan Tecocoyunca Group isa very fossiliferous rich (Corro-Ortiz and Ruíz-González, 2011).The column est unit within the local stratigraphic glomerate (or CualacConglomerate) the old is late Aalenian (early MiddleJurassic)Ñumí Con Ankylosauripus et al. , 2011:281),when bothnamesare inex Cidaris ” and/or “ ” ( Cidaris Tetrapodosauripus baiglmsoe f-bearing limestone) of et al. , 1993). The , 1993). The ” (Kap ” et al. ------, of Tlaxiaco,westernOaxaca,southern Mexico. Figure 1 (subarkoses, litharenitesshale, and graywackes), sandstones enciadas Formationof a succession is Zorrillo-Taberna 1986). The termann, Indifer from the Taberna Formation (Sandoval and Wes tosphinctes the ammonites: of duetoitscontent age.determined age was This Middle Jurassic(Bajocian) ciadas Formation of Regional map and geographic location of the Tlaxiaco tracksite (white asterisk), near the Ñumí River, northwest from the City the fromnorthwest River, Ñumíthe near asterisk), (white tracksite Tlaxiaco the location of andgeographic map Regional Buckman and Duashnoceras Parastrenoceras Westermann, Ochoterena Lep Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín - - - ly registered inashale layer. the tracks and/or concave epireliefs were original or convex hyporeliefslayer,a sandstone in while saurian tracks, these are preserved asnatural casts theankylo the caseof In 20–70cm. of thickness stone layers are irregular and discontinuous witha lar-shapedthe sand in thickness; and10–40cm and thincoalbeds. shale layers The are tabu /2018 381 381 - - - -

Middle Jurassic ankylosaur tracks from Mexico GEOLOGICAL SETTING Middle Jurassic ankylosaur tracks from Mexico MATERIAL AND METHODS 382 382 3. Materialandmethods Figure 2 additionally,rubber silicon and resin molds casts markers; ink waterproof on aplasticsheet using the tracks wasdrawnankylosaurian outline of The / Stratigraphic column150 nearÑumí River,at Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín –

190 mfootprints areindicated. /2018 CFZ-Zt 306, an ankylosaur manusCFZ-Zt 306, an ankylosaur natural sand manusCFZ-Zt 305,ankylosaur and pes; and bers: Autónoma de México under the catalogue num dios Superiores Zaragoza, Universidad Nacional the Facultad de Estu leontological Collection of and other materials, are now housedat the Pa the ankylosaur footprints were made. These, of - - - - 4.1. MATERIAL 4. Results asterisk. with thewhite is marked this block the ankylosaurofprovenance with arrowhead footprints.Thesite dinosaurs. pointstotherockblock The white preserved footprints,thesewere left inawater-saturatedsediment; totheright,well-preserved footprints ofsauropod and theropod Figure 3 sandstone; however, asmentioned above, the fine-grained (Figure 6C); the block is composed of manus-pes setandapartial pes were recognized tracks, the ankylosaurian a 6A, B).Inthe case of vex hyporeliefs), aswell as plant leaves (Figure preservedlosaurian tracks natural as (con casts fallen rockThe block at bears least three anky a conventional protractor. standardusing metric tapes, aVernier caliper and were thetracks taken stone cast.Measurements of Ichnofamily Tetrapodosauridae Sternberg, 1932 General viewof theTlaxiacotracksite.Blackarrowspointtotwodifferent footprint concentrations. Totheleft, badly- Ichnogenus Systematic ichnology Tetrapodosaurus Tetrapodosaurus (Figure 6) Sternberg, 1932 isp. Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín - - 4.2. DESCRIPTION IV). The distancebetweenIV). The the fortoe 9 cm tips is 89º (digits I – thus, the digit total divarication isof 25.5º for digits III – IV; for digits II – III, and of 22º for digitsI–II,41.5º interdigital are angles of and 26cminmaximum medio-lateral width. The suresmaximumin 33cm antero-posterior length impressed inthe sediment. Pes impressionmea curved toe tips, that suggesting thesewere deeper Additionally, digitsIIIandIVpreserve ventrally these are curved and show an outward orientation. slightly elongated, with faintly acuminated tips; heel, short andstout digits IandII,III,IV rounded well-defined a presents pression Pes impression istetradactyl (Figure 6C); this im cast. 306 formanus the ankylosaur natural sandstone for themanusankylosaur andpes, and CFZ-Zt shale layer. catalogue The codes are CFZ-Zt 305 tracks were originally preserved in a carbonaceous /2018 383 383 - -

MATERIAL AND METHODS / Middle Jurassic ankylosaur tracks from Mexico RESULTS Middle Jurassic ankylosaur tracks from Mexico RESULTS 384 384 was cleaned. Hammer forscaleinB,the inCand Dequals 10cm. discovered under thewaterofÑumí River,note thewell-defined claws,mudrim (mr) and tadpolesthatarrivetothefootprintafterit rotated totheright;E.Sauropodmentioned,was footprint,association withtheonesabove insteadit thisfootprintin direct isnot a largetheropod; C.Collapsedtheropod footprint,notethehalluximpression(I), II and toIV;D.Sauropod digits footprint, withdigits Figure 4 previously described (Figure 6C). step,in length, 63.5cm with the pes impression block ridges, a single thus it is possible that it forms the pes impressionsecond preservedis inoneof cm for digitsIII – IV. a anterior portion of The fordigits I–II,17.5cm digitsII–III,and10.2 / Dinosaur footprints attheTlaxiaco tracksite.A.General view oftheoutcrop;B.Sauropod footprint, partiallyoverstepped by Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín /2018 while the other digits are shortandblunt (Figure observed as asmallbump located posterolaterally, respectively;and 16cm, being 21cm digit V is that amanualpresent; padis wider than long, it is arough pentagon (Figureclear 6C);itis line of out the fits and pentadactyl is impression Manus - 4.3. COMMENTS tracks was identified through petrographic slides petrographic through identified was tracks original levelThe containing the ankylosaurian direction. two individualstraveling in the same of stepping thirdis that possibility these representtracks over locomotion.A bution due to a particular mode of and/or thatal organism the footprints hadadistri that the individu manus-pes setbelongstoasingle track representsa left one (Figure 7C).Itimplies set, themanustrack represents arightoneandpes these tracksrepresenting a manus-pes In spite of ure 6A). portion; it is here presumed to be a tail drag (Fig with anacute posterior end andawideranterior footprints.slightly elongate, Itis an arch, forming A curved structurepreserved is together with these – V). Thus, the digit total divarication is 199º (digits I tween digits III –IV, and55º between digits I –V. digits I –II,33º between digits II–III,55.5º be between angles digits is55.5ºbetween6C). The – V. Thus, the total digit divarication is185º (dig tween digits III–IV, and58ºbetween digits IV digits I–II,42ºbetween digits II–III,30ºbe betweenure angles digits is55º between 6C). The short andblunt (Figure 7A, B;compare with Fig located posterolaterally, while the other digits are respectively;observed digitV is asasmallbump It is wider than long, being 26.3 cm and 16 cm, and rounded digital impressions(Figure 7A, B). tracks,pad inthese ankylosaur inhaving small apalmar scribed above; the presence itsuggests of features asthe hand impressionmorphological de natural(Figure 7).This cast presents the same was found, as aneroded footprint-bearing layer ahand Additionally, anisolated sandstone castof (Figure 8). ered, it is possible to note one handimpression servednatural as although weath casts; sandstone identified were addition to this, two other ankylosaurian tracks ated rock layer (Figure 3), both being litarenite. In through the track-bearing rockblock andassoci in situ (Figure are 8). These pre Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín ------5. Discussion 5.1. PRODUCER OFTHETRACKS cast, thefitwas remarkable (Figure 7D). Edmontonia the nodosaurid the palmar view of of photograph hand natural this cast (Figure 7E). A some areas of impressions faintskin are preserved in patchesof manus the ankylosaurian (Figure 7C, D).Small of the functional mechanics is, perhaps, indicative of geneously impressed in the sediment; this feature gesting that theoriginal footprintnot homo was with amedium-lateral concavity(Figure 7C);sug natural cast isthat it preserves a palmar surface this its I – V). An additional interesting feature of et al. (McCrea I digit or digit inner shorter a and flesh) and longer toe impressions( al. (digit I) islarger than in ( ley andHunt, 1995), it has shorter toe impressions topsipes both ichnogenera are tetradactyl; however, in that digits are better defined in is differences conspicuous most the of One 2001). tion to the pes size in to thepessize in have a pentadactyl manus, it is smallinproportion al. penter, 1984;Lockleyand Hunt,1995;McCrea and ceratopsians, ankylosaurs respectively (Car of dosaurus two ichnogenera, of general morphology prints. For compared this purpose, the authors the inate between ceratopsianfoot andankylosaur criteria that help to discrim some morphological Crea andceratopsians ankylosaurs (Mc with thoseof allow thesetracks the comparison eral features of as tetradactyl pesandpentadactyl manus; the gen contain obvious tracks features Tlaxiaco The such i.e. , 2001). , 2001).Although Ceratopsipes , with more enclosing flesh), and the inner digit , 2001). Based onthese features, the Tlaxiaco et al. pes is roughly pesis symmetricalinoutline (Lock and Tetrapodosaurs , 2001). McCrea hand was digitallyhand was superimposedtothis Ceratopsipes (McCrea Ceratopsipes Tetrapodosaurus Tetrapodosaurus , which represent the tracks bears anasymmetricalpes bears Tetrapodosaurus et al. i.e. andlarger in propor et al. , 2001). The pes in , 2001).The , withlessenclosing Tetrapodosaurus (2001), refer to /2018 and (McCrea (McCrea Ceratopsipes Tetrapo than Cera et al. 385 385 et et ------,

Middle Jurassic ankylosaur tracks from Mexico RESULTS / DISCUSSION Middle Jurassic ankylosaur tracks from Mexico DISCUSSION 386 386 Indiferenciadas Formation. Figure 5 39) and it is now39) anditis consideredin asankylosaurian unusually large (Leonardi,Ankylosauria” 1994: “ however, inasubsequent work,he mentioned that ble relationship witha ceratopsid or an ankylosaur; tosí Group), a possi inBolivia;the author suggested for atrackwayfrom the ElMolinoFormation (Po Ligabueichnium theropods (Sennikov, 2006). the ichnogenus Haubold (1971). However, still relate someauthors nally considered as produced byby anankylosaur compared thisichnogenusto the pes impressionsand based the similarity of (Zakharov, 1964); however, McCrea sidered as produced from a theropod dinosaur Initially, the ichnogenus 1984. rapous 1994; Sternberg, 1932; and included losaurian dinosaurs ichnogenera considered as produced from anky summarizedthese ankylosaur tracks;authors the McCrea tracks are undisputable, ankylosaurianinorigin. / Ligabueichnium bolivianum Comparative table of the Jurassic outcropping lithographs in the Mixteco Terrane. F. Z-T I, means Zorrillo-Tabernameans I, Z-T F. Terrane. Mixteco in the outcroppinglithographs the Jurassictable of Comparative Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín Nopcsa,1923,and Macropodosaurus et al. (01 eiwdtegoa eodo (2001) reviewed record the global of , wasestablished by Leonardi (1984) Macropodosaurus Deltapodus Zakharov, 1964; may be attributed to an Macropodosaurus Ligabueichnium Whyte andRomano, Metatetrapous tosegnosaurian Tetrapodosaurus et al. Leonardi, was con was (2001), Metatet , origi ------/2018

and Cedar Mountain formations in U.S.A.in and Cedar Mountain formations (Chin the Arundel in late Early Cretaceous sediments of ceratopsians are teeth collected earliest record of tracks,to mentionthat Tlaxiaco the necessary itis Regarding apossible ceratopsian originfor the Tetrapodosaurus tracksstronglythe Tlaxiaco resembles that of of pentadactyl manus, the general morphology to a tetradactyl pes withwell-developed heel and (McCrea rid ankylosaurs nodosau to confidence with attributed now is it as ceratopsian inorigin, initially interpreted was mation in BritishColumbia, Canada. Although, it the Lower Cretaceous Gething For sediments of (1932), based onatrackway foundSternberg in ichnogenusThe 2009; Mateus ( stegosaurian dinosaurs is widely considered as an ichnotaxon made by bya thyreophoran dinosaur;currently, producedtheseas tracks sequently reinterpreted by a sauropod dinosaur. Lockley Yorkshire,of they it, as made England; interpreted reported this ichnotaxon from the Middle Jurassic regard to origin byseveral (McCrea authors Deltapodus . et al. Tetrapodosaurus , 2011). , Whyte andRomano(1994) e.g. et al. , MilànandChiappe, , 2001).Inaddition was established was by et al. et al. (1994) sub , 2001).In Deltapodus - - - -

pes (p, digits I –IV). IIpes (p,digits the ventrally impressed Note digits toIV of thepes(p) andthe upper-left apartialof thephotograph. pes(pp)at lucerensis center of thephotograph andof thesupposed awell-preservedasterisk isintheplace impressionofataildrag(td),thewhite Figure 6 Scale for Bequals 2cm,scaleinCequals10cm. Ankylosaur footprints intherockblock.A. General viewoftheblock, note theankylosaur footprints ( leaf detailed inB;C.Ankylosaur footprints( Tetrapodosaurus Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín ), note the pentadactyl manus (m, digits I–V)and), notethepentadactyl thetetradactyl manus(m,digits Tetrapodosaurus /2018 Zamites ) atthe 387 387

Middle Jurassic ankylosaur tracks from Mexico DISCUSSION Middle Jurassic ankylosaur tracks from Mexico DISCUSSION 388 388 color ones are modified to fit the digit position assuggestedthe digitbynaturalcast;E.Possibleskinimpressions.color onesaremodified ScaleinEequals1cm. tofit D. Palmar view of sandstone cast andof sandstonePalmar view superimposed cast manus elementsofD. thenodosaurskeletal Figure 7 h orsnFraino Western Colorado Formationthe Morrison of Carpenter rison Formation (Kirkland andCarpenter, 1994; comesfrom ankylosaurs the Late Jurassic Mor of al. Zhiming, 1993;Carpenter Middle Jurassic in Europe and Asia (Galton, 1983; aresaurian dinosaurs known to occur sincethe tracks. the Tlaxiaco Ankylo of the trackmakers Middle Jurassicage, ceratopsians are discarded as (Wolfe andKirkland, way,this 1998). In beingof Moreno HillFormationNew Mexico in of posits large ceratopsians isknown from Turonian de nery / , 1998). In North America, theearliest, 1998).In record CFZ-Zt306, Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín et al. , 1998). However, the earliest record of et al. Tetrapodosaurus 98;i at h eiet f, 1998);infact, the sediments of et al. manus.It isarightmanusnaturalsandstonecast.A.Palmarview;B.DorsalC.Distal , 1998;Kirkland et - - - /2018 (2001) mention two trackways,ankylosaur from ratheraddition, McCrea dried sediment.In impresseddeeply tip digits, andwere impressed in British Columbia, Canada, preserve Formation of manian et al. similar situation hasbeen mentioned by McCrea these were impressed deeply inthe sediment. A tips, digits III and IV, that indicates in such a form ankylosaur pespreserves Tlaxiaco The the toe has beenillustrated by Lockley track resembles the manus of from the Late Jurassic (Hups havetrack known yielded ankylosaur the only (2001); these authors noted that (2001); these authors some Ceno Tetrapodosaurus Edmontonia tracksfrom the Dunvegan (in white color), theblack (inwhite Tetrapodosaurus et al. et al. (2014). , 2008). This , 2008). This and et al. -

tion (Senter, 2011). However, the the features of configura metacarpal ankylosaurian the as well the hand impressions, as of on track morphology feature(Senter, for ankylosaurs 2011);thisbased have that suggested an unexpected apalmar padis the ankylosaurian manus. Some authors ics of the functional mechan suggesting, aswell, part of geneously impressed inthe sediment; a feature thatsuggests the original footprint was not homo a ventral medio-lateral concavity (Figure 7C). This ure 7) that a well-developed bears palmar pad with the hand from (Fig Tlaxiaco lated natural cast of bya similar condition could be suggested the iso the tail. Indeed, the ground; perhaps for the use of losaur pes, at agoodsubjectionto least suggesting the ankly sights into the mechanical function of ankylosaur footprints,the Tlaxiaco could yield in Findings from Canada and Bolivia together with Crea the toes intoanunderlayer” (Mc distal portionof the sediment and represent the penetration of of weretracks an overlyingmade on perhaps layer ia; where that thetrackwaysto suggest the “seem Boliv the Maastrichtian El MolinoFormation of Sauropelta Carpenter Zhiming, 1993;Kirkland andCarpenter, 1994; longer than 3m(Galton, 1983; Carpenter, 1984; and saurus such as small; forms were Ankylosauria the earlyof members Most of an occasionaltaildrag. thus possible1984). Itis thatleft somenodosaurids nodosaurids, such as been estimatedhas 40 to50caudalvertebrae for Euoplocephalus ter, 1982,1984). For example, the ankylosaurid tail than that present (Carpen in ankylosaurids regard to this,had alonger nodosaurid dinosaurs associatedfootprints. to ankylosaur However, in preserved; no tail impressionsare known to occur Together with the tracks, a supposed tail drag is apalmarpad. support thepresence of threehand impressions ankylosaur from Tlaxiaco Cryptodraco inNorthAmerica, et al. , which hasbeen regarded as the track , 2001:442). et al. had 21 caudal vertebrae; while it and , 1998). However, the nodosaur Dracopelta Sauropelta Mymoorapelta Tianchisaurus inEurope, were not (Carpenter, 1982, and inAsia, Gargoyleo Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín ------5.2. PALEOENVIRONMENTAL CONDITIONS fied in the plant community; among these, community; among plant the in fied the 34 speciesidenti most diverse order with 17of aco dinosaur footprints include Bennettitales, the plant macrofossilsThe associated with the Tlaxi ism Tlaxiaco 1984; McCrea pelta When compared with the data raised from and 1500kg,5.2 m respectively(Carpenter, 1984). approximately a calculated length andweight of 1984; McCrea the maker of ml lae; n hs ae 7% f te identified the plants had microphyl leaves with an area between of 72% case, this in leaves; of small high percentage a bears flora identified The Zhou, 2009). local climate (Rees mesic conditions, aswell as little variations in the aroughsuggests mountainrelief, temperate and GinkgoalesandConiferales in the study area of and Delevoryas, 1982).However, the presence of Mexico haveclimate (Person been associated to awarm Jurassic the in identified conifers of ter, 2002;Rojas-Chávez, 2010); while the genera (Vanseasons with humid Konijnenburg-Van Cit with Equisetales, have been associated to a climate are important herbaceous elements and,together Sphenobaiera the genera eral within new species order2016). The Ginkgoales isrepresented by sev and Velasco-de 2012; Lozano-Carmona León, uncertain taxonomic position(Lozano-Carmona, and frequent respectively, however, bothare of Trigonocarpus oaxacensis Mexiglossa varia kidstonii rare. are Conifers represented by dium 2009; and McLoughlin, dant, while and lucerensis and ca. Antevs, 1919aswell as Otozamites hespera 3.8minlengthandnearly 1tinweight. Etheridge, inJack andEtheridge, 1892. (Wieland) Personand Delevoryas, 1982 Tetrapodosaurus Tetrapodosaurus (Velasco-de León Anomozamites triangularis Delevoryas andPerson, 1975and et al. et al. Tetrapodosaurus et al. , 2001), was an organism with , 2001),wasanorganism , 2001;Sternberg, 1932), the Wieland, 1914 are common Wieland, 1914, are abun footprint size (Carpenter, , 2000;Wang Anomozamites tracks suggest an organ tracks suggest Zamites tracks(Carpenter, et al. Podozamites /2018 (Nathorst) Pott Ginkgoidium sp., are rather , 2015).Ferns sp. cf. et al. interme , 2005; Zamites sp. cf. Sauro and 389 389 ------

Middle Jurassic ankylosaur tracks from Mexico DISCUSSION Middle Jurassic ankylosaur tracks from Mexico DISCUSSION 390 390 Figure 3;B.Fossilized log;C. Figure 8 and environmentalduring itsforma conditions the homogeneous depositional that permitted leobasin was subject to a continuous subsidence rillo-Taberna Indiferenciadas Formation. pa The the coal layers, 1.5mthick,present in the Zor organic matter that formed a great amountof establishment;swamps accumulate these swamps low water circulation in the floodplain allowed the sub-humidclimate,warm, andwithperiodsof asub- feature This indicatesof thedominance microphyl 1type 0.08241 to1.3660cm / Locationof provenanceoftherockblockbearing Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín sensu In situ Ortiz-Martínez 2 (Lozano-Carmona, 2012; (Lozano-Carmona, manus sandstonein dorsalview(scale10cm). cast et al. , 2013). Tetrapodosaurus - - - /2018 evto geswt hto McCrea servationwith that agrees of lo-Taberna Indiferenciadas Formation.ob This such asthe Zorril in a coal-bearing formation, trackswere ankylosaur nodosaurid Tlaxiaco found In regard tothe paleoecological conditions, the these the nodosauridankylosaur,ed is represented by communities present at area, the Tlaxiaco includ the Middle Jurassic herbivorous dinosaur diet of the Indiferenciadas Formation surely were part of plant remainspreserved inthe Zorrillo-Taberna tion (Corro-Ortiz and Ruíz-González, 2011). The footprints.A.Thesiteismarked withawhiteasteriskin Tetrapodosaurus tracks. et al. (2001); - - - Acknowledgements 6. Conclusions h rsneo presenceThe of cal conditionssinceMiddleJurassic times. was adapted Ankylosauria to similar paleoecologi mation, that suggest at least the North American such asthe Zorrillo-Taberna Indiferenciadas For tracks are preserved in a coal-bearing formation, fact that nodosaurid ankylosaur The the Tlaxiaco ure 6B). the same surfaceof Zamites lucerensis co-de Léon Formationciadas 2012; Velas (Lozano-Carmona, remains found inthe Zorrillo-Taberna Indiferen coalandplant supported bythe great amountof Crea for well-vegetated andwell-watered lowlands(Mc facies. Also,seem tohave ankylosaurs apreference floodplain and coal-bearing in concentrated are mention that these footprintsauthors ankylosaur tribución de Gimnospermas enel Jurásicotribución de Gimnospermas de la de Oaxaca”, and PAPIIT-IN-106010-3, “Dis en el Jurásicoy Distribución de Gimnospermas CYT-103773, “Reconstrucción Paleoclimática workThis was financed through projects: CONA thetracks. the siliconerubber moldand the castof sidad NacionalAutónoma de México) for making Gerardo Reyes (Univer to also season; field 2011 the April of Authorswant tothankmembers and medium,for thesethyreophoran dinosaurs. seems represented byat least two bodysizes, small way, the diversity ankylosaur at the Middle Jurassic ankylosaurian ichnofossilsknown to date. Inthis times. Also, thesefootprints represent theoldest North America duringMiddle Jurassicsouthern ic a geograph Mexico indicates the existence of of continuum et al. , 2001). This environmental, 2001). This condition is i h eodo the to Ankylosauria inthe record of et al. leaves were found preserved in the , 2013).Even more, well preserved Tetrapodosaurus Tetrapodosaurus tracks inthe south footprints (Fig Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín ------References Antevs, E., 1919, Die liassische flora des flora liassische Die 1919, E., Antevs, Paleoecológicas). rados enMéxico:ImplicacionesPaleobiológicas y 2015-36941 (Diversidadde Vertebde Icnofósiles forsupport; their as wellkind as toproject UAZ- Universidadla Tierra, Autónoma de Zacatecas Académicas de Ciencias Biológicas y Cienciasde Paleoecológica”;ción Unidades RARR thanks Región Norte del Terreno Mixteco y Reconstruc Chinnery, B.J., Lipka,T.R., Kirkland, J.I., Carrasco-Ramírez, R.S., 1981,Geología Jurásica Carpenter, K.,Miles, C.,Cloward, K.,1998,Skull Carpenter, K.,1984,Skeletal reconstruction and Carpenter, 1982, Skeletal K., and dermal Kungliga SvenskaVetenskapsakademiens Stockholm, Sweden, Hörsandsteins: History andScienceBulletin,14,297–302. History U.S.A., Natural New Mexico Museumof Albuquerque,Ecosystems: NewMexico, Lower and Middle CretaceousTerrestrial Lucas, S.G., Kirkland, J.I., Estep, J.W. (eds.), North America, Middle Cretaceous of Neoceratopsian teeth from the Lower to Parrish,J.M., 1998, M.K., Brett-Surman, MSc Thesis, 146p. Autónoma de México, Facultad de Ciencias, Mexico City, Mexico, Universidad Nacional del área de Tlaxiaco, Mixteca Alta, Oaxaca: 393, 782–783. a Jurassic ankylosaur(Dinosauria): Nature, of Sciences, 21(12),1491–1498. Earth North America: Canadian Journal of Nodosauridae) from the Cretaceous of life restoration of 689–697. EarthSciences, 19(4), Canadian Journal of Alberta: Cretaceous Oldman Formation of Ankylosauridae) from(Ornithischia: the Late reconstruction of armor Handlingar, Almqvist & Wiksell, 59(8), 1–71. Sauropelta Euoplocephalus tutus Euoplocephalus /2018 (Ankylosauria: 391 391 in - -

DISCUSSION / CONCLUSIONS / Middle Jurassic ankylosaur tracks from Mexico ACKNOWLEDGEMENTS / REFERENCES Middle Jurassic ankylosaur tracks from Mexico REFERENCES 392 392 Dávalos-Álvarez, O.G., 2006,Evolución tectónica Corro-Ortiz, M.G., Ruíz-González, F.J., 2011, Jack, R.L.,Etheridge, R.jr., Geology 1892,The Hups, K.,Lockley, M.G., Foster, J., Gierlinski,G., Haubold, H.,1971,Ichniaet Amphibiorum González-Torres, E.A., 1989,Geología y Galton, P.M., dinosaurs 1983,Armored Erben, H.K., 1956,El Jurásico Medio y el Delevoryas, T., Person,C.P., 1975, / Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín BSc Thesis, 134p. Autónoma deMéxico, Facultad deIngeniería, Mexico City, secuencias Mexico, Universidad Nacional las Jurásicas de del área de Tlaxiaco, Oaxaca: estratigráfico Análisis Printer, 768p. Australia, JamesCharles Beal, Government Queensland: Queensland, Geological Map of New Guinea,withsixty-eigth plates anda Queensland and and Palaeontology of 28, 94A. the VertebrateJurassic: Journal Paleontology, from of track ankylosaur first The 2008, Germany, Gustav Fischer Verlag, 18,123p. Handbuch der Paläoherpetologie: Stuttgart, Reptiliorum Fossilium, Ingeniería, BScThesis, 188p. Nacional Autónoma de México, Facultad de Oaxaca: MexicoCity, Mexico, Universidad Paleomagnetismo del área de Tezoatlán, Palaeontographica AbteilungA,182,1–25. Europe: Middle andUpper Jurassic of from Ankylosauria) (Ornithischia: the 11–36. City, Mexico, Sociedad Geológica Mexicana, Mexico Geológico Internacional: Congreso Caloviano de México (abstract), 114–120. Palaeontographica Abteilung B, 154, Oaxaca, Mexico:leaves from the Jurassic of gen. et sp. nov., Glossopteroid anewgenusof Centro deGeociencias, MScThesis, 132p. Universidad NacionalAutónoma de México, de Oaxaca: Juriquilla, Querétaro, Mexico, cenozoica en la porción norte de la falla in Kuhn,O. (ed.), Mexiglossa Mexiglossa varia in XX /2018

Kirkland,J.I., Carpenter,Hunt, A.P., K., Scheetz, Kirkland, J.I., Carpenter, K.,1994,North Kappus, E.J., Lucas, S.G., Langford, R.,2011,The Lockley, M.G., Hups, K.,Trujillo, K.,Gerwe, D.S., Lockley, M.G., Meyer, C.A., Hunt, A.P., Lucas, Lockley, M.G., Hunt,A.P., 1995,Ceratopsid South Leonardi, G., 1994, Annotated atlas of Leonardi, G., 1984,Leimpronte fossilidi dinosauri, 40, 25–42. Brigham YoungStudies, UniversityGeology Western Colorado: Formation Morrison of (Dinosauria) from the Upper Jurassic ankylosaur pre-Cretaceous first America’s andScienceBulletin,53,272–288. History U.S.A., Natural New Mexico Museumof Fossil Record 3:Albuquerque, NewMexico, R.M., Lucas, S.G., Spielmann, J.A. (eds.), USA, andChihuahua,Mexico, tracksites, SundlandPark,New Mexico, Cerro de Cristo Rey Cretaceous dinosaur western North America:Albuquerque,western New M.G., Lucas, S.G. (eds.), Fossil footprints of andmanagement, paleoecology Western Colorado: implications for Area of Dominguez-Escalante National Conservation 2014, Mesozoic vertebrate tracksites from the Gaia,10,233–248. tracks andtrackmakers: sauropod S.G., distribution 1994,The of Vertebrate Paleontology, 15(3), 592–614. Colorado: Journal of Maastrichtian) of Laramie Formation (Upper Cretaceous: tracks andassociated ichnofauna from the de Pesquisa deRecursos Minerais, 246p. Central America: Brasilia, Brazil, Companhia Mexico and Holocene), with an appendix of America tetrapod footprints (Devonian to Errizo Editrice, 165–186. dei Dinosauri: Venice,Sulle Orme Italy, Leonardi, G., Morello, N., Taquet, P. (eds.), P., de Ricqles, A.,Kielan-Jaworowska,Z., in Formation: Geology, Modern 23,145–177. fromspecimens the Upper Jurassic Morrison R.D.,(Dinosauria) 1998,Ankylosaur Bonaparte, J.F., Colbert, E.H.,Currie, in in Sullivan, Lockley, Mateus, O., Milàn,J., Romano, M.,Whyte, M.A., Martínez-Díaz, J.L., Montellano-Ballesteros, D.E.,Lozano-Carmona, Velasco-de León, M.P., D.E.,Lozano-Carmona, 2012,Paleoclima Ortiz-Martínez, E.L., Velasco-de León, M.P., F.,Nopcsa, 1923,DieFamilien der Reptilien: Milàn, J., Chiappe, American L.M., 2009, First McCrea, R.T., Lockley, M.G., Meyer, C.A., 2001, Mexico City, Mexico, Universidad Nacional Zorrillo-Taberna Indiferenciada, Oaxaca: FósildeRíoÑumí,FormaciónFlora y 215–223. Natural andScience Bulletin, 62, History Mexico, U.S.A., NewMexico Museumof Geology, 117(3),343–348. Stegosaurian Footprints: Journal The of of brodricki the JurassicIchnospecies Record of U.S.A., IndianaUniversity Press, 413–454. Bloomington, Indiana, dinosaurs: armored track occurrences, ankylosaur purported Global distribution of 56(3), 651–658. Portugal: Acta Palaeontologica Polonica, from tracks the Upper Jurassic LourinhãFormation, stegosaur of finds New 2011, Mexicana dePaleontología, 93. de Paleontología: Puebla, Mexico, Sociedad México (abstract), del Ankylosauria) Cretácico Superior de (Thyreophora-2011, Anquilosaurios M., Mexicana, 5(2),87–101. in the Mixteco Terrane: Paleontología findings recent Mexico: of prospects and importance Southeast in flora Jurassic 2016, Superiores Zaragoza, BScThesis, 174p. Autónoma deMéxico, Facultad de Estudios Ciencias Geológicas, 30(1),150–158. Oaxaca, México: RevistaMexicana de delas foliar de lazonafósiles norte de gimnospermas área del Clasificación 2013, Salgado-Ugarte, I.,Silva-Pineda, A., 2, 1–210. Fortschritte der Geologie und Palaeontologie, adaRve fthe Fossil andaReviewRecord of in in Carpenter, K.(ed.), The XII Congreso Nacional XIICongreso Deltapodus Deltapodus Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín Rees, P.McA.,Ziegler, Valdes, A.M., P.J., 2000, Pott, C., McLoughlin,S., 2009,Bennettitalean Person,C.P., Delevoryas, T., 1982,The Pérez-Ibargüengoitia, J.M., Hokuto-Castillo, Rodríguez-de la Rosa,2015, Hace72 R.A., Rodríguez-de la Rosa, R.A.,2014,Sinopsis Rivera-Sylva, H.E.,Carpenter, K.,Aranda- Rivera-Sylva, H.E.,Espinosa-Chávez, B., 2006, Jurassicphytogeography and climates: New and Palynology, 158,117–166. Palaeobotany Sweden: Reviewsouthern of Scania, of floras Jurassic) Triassic–Middle foliage from the Rhaetian–Bajocian (latest Mexico: Oaxaca Palaeontographica Abteilung B, 180,82–119. of flora Jurassic middle Paleontología Mexicana, 21,5–22. parte centromeridional del Estado de Puebla: paleontología del Jurásico Superior de la Z.de, y A., Cserna, 1965, Estratigrafía de Cultura,MuseodelDesierto, 179p. Chihuahua, Mexico, Instituto Chihuahuense de México: dinosaurios Los millones deaños: finalSNIB-CONABIOInforme LU006, 79. Universidad NacionalAutónoma de México, de Paleontología: Guanajuato, Mexico, Paleontología Nacional and XIIICongreso Latinoamericano(ed.), VIII Congreso de México (abstract), sobre lapaleoicnología de vertebrados en Geológicas, 28(3),371–378. from Mexico: Revista Mexicana de Ciencias Ornithischia) (Ankylosauria: nodosaurids Manteca, F.J., 2011,Late Cretaceous 6, Letter2. de Géologie/Notebookson Geology, Carnets Coahuila, Mexico: del Pueblo Formation of from the upper Cretaceous Cerroosteoderms (Dinosauria: Thyrephora)Ankylosaurid Cambridge University Press, 297–318. climates Cambridge, in Earth history: U.K., MacLeod, K.G., Wing, S.L. (eds.), Warm data and modelcomparisons, in Reynoso-Rosales, V.H. /2018 in Huber, B.T., 393 393

Middle Jurassic ankylosaur tracks from Mexico REFERENCES Middle Jurassic ankylosaur tracks from Mexico REFERENCES 394 394 orge‐e a oa RA, eac‐e León, Velasco‐de R.A., Rosa, la Rodríguez‐de Sternberg, C.M.,1932,Dinosaurtracksfrom Silva-Pineda, A., Velasco-de León, M.P., Senter, P., 2011,Evidencefor asauropod-like Sennikov, A.G., 2006,Reading segnosaurtracks F.,Sedlock, R.L., Ortega-Gutiérrez, Speed, R.C., Sandoval, J., Westermann, G.E.G., 1986,The Rojas-Chávez, C.,2010,Taxonomía de / Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín Nacional de Paleontología: Guanajuato, de Paleontología and XIIICongreso V.H. Latinoamericano(ed.), VIIICongreso (abstract), de México El 2014, registro de huellas devertebrados del Jurásico D.E., Lozano‐Carmona, M.P., Annual Report for 1930, 59–85. Canada Canada, National Museumof Peace River, BritishColumbia:Ottawa, Jurásico: Mendoza, Argentina, 76. México (abstract), de plantas Jurásicas deOaxaca Puebla,y Rodríguez R.,2007,Tafonomía Becerra, 56(1), 221–224. Acta Palaeontologicadinosaurs: Polonica, ankylosaurian in configuration metacarpal (in Russian): Priroda, 5,58–67. p. America, Special Paper 278, 153 Society of Mexico: Geological tectonic evolution of 1993, Tectonostratigraphic and terranes 60(6), 1220–1271. Paleontology,Oaxaca, Mexico: Journal of Bajocian (Jurassic)ammonite fauna of Zaragoza, BScThesis, 121p. de México, FacultadSuperiores deEstudios Mexico, Universidad NacionalAutónoma la región Mixteca, México: Mexico City, Matoniaceae (Filicales) del Jurásico en Dicksoniaceae, Gleicheniaceae y LU006, 79. SNIB-CONABIO final Informe México, de Mexico, Universidad NacionalAutónoma in IIISimposioArgentino in Reynoso-Rosales, /2018 Velasco-de León, M.P., D.E., Lozano-Carmona, Velasco-de León, M.P., Ortiz-Martínez, E., Van Konijnenburg-Van Cittert, J.H.A.,2002, Wolfe, D.G., Kirkland, J.I., 1998, Wieland, G.R., liásicadela 1914,LaFlora Whyte, M.A.,Romano, M.,1994,Probable Wang, Y., Guignard, G., Thévenard, F., Dilcher, nentoa ora fPaleobiology, JournalInternational 27, of Mexico:Historical Biology, Jurassic An of Ginkgoalesfrom theMiddle of species O.D., Silva-Pineda, A., 2015,Two new M.A.,Martínez-Paniagua, Flores-Barragan, Paleontología Mexicana, 63,122–143. fósilesdel Terrenogimnospermas Mixteco: 2013, Distribución yambientes de las D.E.,Silva-Pineda, A., Lozano-Carmona, Palaeobotany andPalynology, 119,113-124. in Eurasia:Review Cretaceous ferns of someLate Triassicto Early of Ecology 303–317. Natural and Science Bulletin, 14, History Mexico, U.S.A., NewMexico Museumof Terrestrial Albuquerque,Ecosystems: New J.W. (eds.), Lower and MiddleCretaceous Mexico, west-central(Cretaceous, New Turonian) of dinosaur from the Moreno HillFormation christopheri de México, 31,1–65. Mixteca Alta:Boletín del InstitutoGeológico 15–26. Sauropod Paleobiology:Gaia, 10, of Aspects Santos, V.F., Meyer, C.A.,Hunt,A.(eds), Yorkshire,of England, sauropod footprints from the Middle Jurassic Botany, 92(4),709–721. Journal Hubei,China:American of of huangii S., 2005,Cuticular anatomy of D., Barale, G., Mosbrugger, V., Yang, X.,Mei, 366–373. (Ginkgoales)from theLower Jurassic in n. gen. & n. sp., a ceratopsian Lucas, S.G., Kirkland, J.I., Estep, in Lockley, M.G., Dos Sphenobaiera Zuniceratops Zakharov, S.A., 1964,Onthe Cenomanian Tadzhikskoi SSR,31–35. Dushanbe, Tajikistan, Ajadennuta Bayj V.M. Tadzhikistan: (ed.), Paleontologyof in the Shirkent River Valley, which weredinosaur, found the tracks of in Reiman, Boletín de la Sociedad Geológica Mexicana Geológica Sociedad la de Boletín Zhou, Z-.Y., fossil 2009,Anoverview of Zhiming, D., (ornithischian ankylosaur 1993,An Ginkgoales: Palaeoworld, 18(1),1–22. 10, 257–266. Junggar Basin, China:Vertebrata PalAsiatica, the dinosaur) from the Middle Jurassicof /2018 395 395

Middle Jurassic ankylosaur tracks from Mexico REFERENCES