A new species of Lapparentophis from the mid-Cretaceous Kem Kem beds, Morocco, with remarks on the distribution of lapparentophiid snakes

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A new species of Lapparentophis from the

mid-Cretaceous Kem Kem beds, Morocco, with remarks

on the distribution of lapparentophiid snakes

Romain Vullo

To cite this version:

Romain Vullo. A new species of Lapparentophis from the mid-Cretaceous Kem Kem beds, Morocco,

with remarks on the distribution of lapparentophiid snakes. Comptes Rendus Palevol, Elsevier Masson,

2019, 18 (7), pp.765-770. �10.1016/j.crpv.2019.08.004�. �insu-02317387�

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ContentslistsavailableatScienceDirect

Comptes

Rendus

Palevol

www . s c ie n c e d i r e c t . c o m

General

Palaeontology,

Systematics,

and

Evolution

(Vertebrate

Palaeontology)

A

new

species

of

Lapparentophis

from

the

mid-Cretaceous

Kem

beds,

Morocco,

with

remarks

on

the

distribution

of

lapparentophiid

snakes

Une

nouvelle

espèce

de

Lapparentophis

du

Crétacé

moyen

des

Kem

Kem,

Maroc,

et

remarques

sur

la

distribution

des

serpents

lapparentophiidés

Romain

Vullo

UniversitédeRennes,CNRS,GéosciencesRennes,UMR6118,35000Rennes,France

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received27February2019

Acceptedafterrevision29August2019 Availableonline10October2019 HandledbyNathalieBardet Keywords: Squamata Ophidia Lapparentophiidae Albian Cenomanian NorthAfrica Palaeobiogeography

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Twoisolatedtrunkvertebraefromthe?uppermostAlbian–lowerCenomanianKemKem bedsofMoroccoaredescribedandassignedtoLapparentophis,anearlysnakegenusknown fromcoevaldepositsinAlgeria.TheMoroccanspecimensrepresentanewspecies, Lap-parentophisragei,whichcanbe distinguishedfromthetypeandonlyknownspecies, Lapparentophisdefrennei,byitssmallersize,itsmoreelongatevertebrae,thepresenceof parazygosphenalforamina,andparadiapophysesextendinganteroventrallyclosertothe cotyle.ThediscoveryofLapparentophisintheKemKembedsaddstotherelativelydiverse snakeassemblagepreviouslyreportedfromthisformationandextendsthegeographical rangeofthegenus.ThedistributionofLapparentophisandlapparentophiid-grade (?lap-parentophiid)snakesisdiscussed.Thispoorlyknownfamilyofterrestrialsnakesseemsto berestrictedtothelatestAlbian–earlyCenomanianofNorthAfrica,withtheexceptionof Pouitellafromtheearly–middleCenomanianofFrance.Asformanyothervertebratetaxaof thisperiod,thisdistributionisconsistentwithadispersaleventfromAfricatothewestern partoftheEuropeanarchipelago.

©2019Acad ´emiedessciences.PublishedbyElsevierMassonSAS.Thisisanopenaccess articleundertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4. 0/). Motsclés: Squamata Ophidia Lapparentophiidae Albien Cénomanien AfriqueduNord Paléobiogéographie

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Deuxvertèbresdorsalesprovenantdel’Albienterminal–CénomanieninférieurdesKem Kem(Maroc)sontdécritesetattribuéesàLapparentophis,unserpentbasalconnudans desdépôtséquivalentsenAlgérie.Lesspécimensmarocainsreprésententunenouvelle espèce, Lapparentophis ragei, qui diffère dela seule autre espèce connue, Lapparen-tophis defrennei,parsapluspetite taille,sesvertèbresplusallongées,la présencede foramensparazygosphéniensetdesparadiapophysesplusrapprochées antéroventrale-mentducotyle.LadécouvertedeLapparentophisdanslesKemKemaccroîtladiversitéde l’assemblagedeserpentsdéjàdécritdanscesniveauxetétendladistributiongéographique dugenre.LadistributiondeLapparentophisetdesserpentsdegradelapparentophiidés (?Lapparentophiidae)estdiscutée.Cettefamilledeserpentsterrestres,quidemeuremal connue,sembleêtrerestreinteàl’Albienterminal–Cénomanieninférieurd’AfriqueduNord,

E-mailaddress:romain.vullo@univ-rennes1.fr https://doi.org/10.1016/j.crpv.2019.08.004

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766 R.Vullo/C.R.Palevol18(2019)765–770

àl’exceptiondePouitelladuCénomanieninférieur–moyendeFrance.Commepourde nom-breuxautresgroupesdevertébrés,cettedistributionestenaccordavecl’existenced’une migrationdepuisl’Afriqueverslapartieoccidentaledel’archipeleuropéen.

1. Introduction

Althoughprimitivesnakeshavebeenreportedasearly astheMiddleJurassicbasedonafewjawfragmentsfrom theBathonianofEngland(Caldwelletal.,2015),the mid-dle partof the Cretaceous coincides with an explosive increaseinthesnakefossilrecordworldwide(e.g.,Albino

etal.,2016;ApesteguíaandZaher,2006;CaldwellandLee,

1997; Caldwellet al., 2015; Cuny et al., 1990; Gardner

andCifelli,1999;Hsiouetal.,2014;Kleinetal.,2017;Lee

etal., 1999;Rage, 1988;Rage and Escuillié, 2000;Rage

andWerner,1999;Rageetal.,2016;Tchernovetal.,2000;

Xingetal.,2018).Snakesareparticularlywellrepresented inthe vertebrate assemblagesfrom themid-Cretaceous (Albian–Cenomanian)ofNorthAfrica,withvarious,mostly terrestrial forms described from Morocco (Klein et al.,

2017;RageandDutheil,2008),Algeria(Cunyetal.,1990;

Hoffstetter,1959), Libya (Nessovet al., 1998; Rage and

Cappetta,2002),Sudan(RageandWerner,1999;Werner

and Rage, 1994), and Egypt (Nopcsa, 1925).The genus

Lapparentophis(and the family Lapparentophiidae) was recognised based on three isolated vertebrae found in depositsoflateAlbian–CenomanianageatInAkhamilin easternAlgeria(Hoffstetter,1959).Sofar,Lapparentophis isonlyknownfromthetypelocalityandincludesa sin-glespecies, L. defrennei. In addition,a few vertebraeof possiblelapparentophiidsnakeshavebeendescribedfrom coevaldepositsinnorthernAlgeria(Cunyetal.,1990)and Sudan(RageandWerner,1999;WernerandRage,1994). Outside Africa, thepoorly known genusPouitella is the onlyothertaxontentativelyreferredtoLapparentophiidae

(Rage,1988).HereIreporttheﬁrstoccurrenceof

Lappar-entophisfromtherichanddiversevertebrateassemblage oftheMoroccanKemKembeds.Thematerial,consisting oftwowell-preservedandisolatedvertebrae,representsa newspecies.

2. Geologicalandpalaeontologicalsettings

ThetwospecimenscomefromthelowerpartoftheKem KembedscroppingoutatElBegâa,aproductivefossilsite locatedafew km eastofTaouz (southeasternMorocco)

(seeCavinetal.,2010).ThelowerpartoftheKemKem

bedsliewithintheIfezouaneFormation, whichis com-posedmainlyofsandstonecharacterizedbycross-stratified structuresand channel structures filled with microcon-glomerates (Cavin et al., 2010). These beds are ?latest AlbiantoearlyCenomanianinageandweredepositedin fluvialanddeltaicenvironments(Cavinetal.,2010).The IfezouaneFormationisrenownedforitsrichanddiverse vertebrateassemblage includingselachians,bonyfishes,

lissamphibians,turtles,squamates,pterosaurs, crocodyli-formsanddinosaurs(seeCavinetal.,2010).Thesquamate assemblage consistsmostlyof snakes, includingvarious forms such as Simoliophis cf. libycus, Norisophis begaa, an indeterminate madtsoiid, a possiblenigerophiid and an incertae sedis snake (Klein et al., 2017; Rage and

Dutheil, 2008).Inaddition,three lizardspecimens have

beenreportedsofarfromtheKemKemBeds, correspond-ingtoanisolatedvertebraofanindeterminateform(Rage

andDutheil,2008),ajawfragmentassignedtoan

acrodon-tan(Jeddaherdanaleadonta;Apesteguíaetal.,2016), and adentary ofaborioteiioid(Bicuspidonhogreli;Vulloand

Rage,2018). 3. Systematicpalaeontology LepidosauriaHaeckel,1856 SquamataOppel,1811 OphidiaBrongniart,1800 LapparentophiidaeHoffstetter,1959 LapparentophisHoffstetter,1959

Type species. Lapparentophis defrennei Hoffstetter,

1959.

Lapparentophisrageisp.nov.

Etymology.Thespeciﬁcepithetisinhonourofmylate friendandcolleagueJean-ClaudeRage,whoﬁrstsuggested that thematerialstudiedheremaybelongto Lapparen-tophis,andinrecognitionofhisinnumerableandinvaluable contributionstopalaeoherpetologyand palaeobiogeogra-phy.

Type material. MHNM.KK387 (holotype) and

MHNM.KK388 (paratype), two nearly complete trunk vertebrae (Fig. 1) housed in the “Muséum d’Histoire NaturelledeMarrakech”(MHNM),Morocco.

Typelocalityandhorizon.ElBegâalocalitynearTaouz, southeasternMorocco;KemKembeds,Ifezouane Forma-tion,?latest Albian–earlyCenomanianin age(seeCavin

etal.,2010).

Diagnosis. Aspecies ofLapparentophisdifferingfrom thetype and onlyotherspecies, L.defrennei,in the fol-lowing features:smallersize,more elongate(aslongas wide) vertebrae,presenceof parazygosphenalforamina, paradiapophyses (synapophyses) extending anteroven-trallyclosertothecotyle.

Description. Both specimens are equally-sized, non-pachyostoticmid-trunkvertebraethatcomefromasimilar position.Thetipoftheneuralspineisbrokenonboth spec-imens.Severalfeatures(i.e.,robustgeneralmorphology, centrummoderatelyelongate,neuralcanalsmallerthan cotyleandcondyle,prezygapophyseswelldeveloped) sug-gestthatbothvertebraearefromadults(e.g.,Gardnerand

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Fig.1. PhotographsandinterpretativelinedrawingsoftrunkvertebraeofLapparentophisrageisp.nov.,holotypeMHNM.KK387(A–J)andparatype MHNM.KK388(K–T)inanterior(A,F,K,P),posterior(B,G,L,Q),leftlateral(C,H),rightlateral(M,R),dorsal(D,I,N,S),andventral(E,J,O,T)views. Abbreviations:cd:condyle;ct:cotyle;hk:haemalkeel;izc:interzygapophysealconstriction;izr:interzygapophysealridge;iztf:intrazygantralforamen; lf:lateralforamen;nc:neuralcanal;ns:neuralspine;pctf:paracotylarforamen;pdp:paradiapophysis;poz:postzygapophysis;pozf: postzygapophy-sealarticularfacet;prz:prezygapophysis;przf:prezygapophysealarticularfacet;psb:parasagittalbulge;pzsf:parazygosphenalforamen;scf:subcentral foramen;zs:zygosphene;zt:zygantrum.Scalebar:5mm.

Fig.1. Photographies etdessinsinterprétatifsdesvertèbresdorsalesde Lapparentophisrageisp.nov.,holotypeMHNM.KK387(A–J)etparatype MHNM.KK388(K–T)envuesantérieure(A,F,K,P),postérieure(B,G,L,Q),latéralegauche(C,H),latéraledroite(M,R),dorsale(D,I,N,S)etventrale (E,J,O,T).Abréviations:cd:condyle;ct:cotyle;hk:carènehémale;izc:constrictioninterzygapophysaire;izr:rideinterzygapophysaire;iztf:foramen intrazygantral;lf:foramenlatéral;nc:canalneural;ns:épineneurale;pctf:foramenparacotylien;pdp:paradiapophyse;poz:postzygapophyse; pozf:facettearticulairepostzygapophysaire;prz:prézygapophyse;przf:facettearticulaireprézygapophysaire;psb:renﬂementparasagittal;pzsf: foramenparazygosphénien;scf:foramensubcentral;zs:zygosphène;zt:zygantrum.Barred’échelle:5mm.

Cifelli,1999).Thedescriptionprovidedhereismainlybased

ontheholotype(Fig.1A–J);theparatype(Fig.1K–T) gener-allydisplaysthesamefeatures,unlessindicatedotherwise. Measurementsofbothvertebralspecimensareprovidedin

Table1.

In anterior view (Fig. 1A, F, K, P),the type vertebra showsnodorsoventraldepression.Thecotyleisslightly widerthanhigh.Thezygospheneisrelativelysmall,clearly narrowerthanthecotyle;itshowsaslightlyconvexdorsal marginandtwolateralbulges.Theroofofthezygosphene

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Table1

Measurements(inmm)forvertebraeofLapparentophisrageisp.nov.

Tableau1

Mesures(enmm)desvertèbresdeLapparentophisrageisp.nov.

HolotypeMHNM.KK387 ParatypeMHNM.KK388

Maximumlengthofvertebra 10.7 10.2

Centrumlength(fromcotylarrimtoposteriormostendofcondyle) 8.3 8.4

Cotyleheight 4.1 4.2

Cotylewidth 5.5 5.6

Condyleheight 3.7 3.9

Condylewidth 4.3 5.1

Widthacrossprezygapophyses 10.1 10.6

Widthofinterzygapophysealconstriction 5.8 6.2

Zygosphenewidth 3.5 3.5

isthickerthanthecotylarrim.Thezygosphenalfacetsare oblique.Theneuralcanalistrifoliateandwiderthanhigh; itismarkedlysmallerthanthecotyle.Thelateralmargins ofthehighprezygapophyseal buttressesaresubvertical andslightlyconcave.Theprezygapophysealarticularfacets aremarkedlyoblique,extendinglaterodorsallyat40◦from horizontal;theirmedialendsarepositionedatthelevel ofthedorsoventralmidpointoftheopeningfortheneural canalandtheirdistalendsliejustabovethelevelofthe zygosphenalroof.Paracotylarandsmallparazygosphenal foraminaarepresent intheholotype; however, parazy-gosphenalforaminaseemtobeabsent(orminute?)inthe paratype.Theparadiapophysesextenddorsallyjustabove thelevelofthedorsalrimofthecotyleandanteroventrally lieclose tothecotylar rim(i.e., noparacotylar notches are present). The neural arch is relatively narrow and moderatelyelevated.Posteriorly,theneuralspineiswell separatedfromtheroofoftheneuralarch.

Inposteriorview(Fig.1B,G,L,Q),thecondyleisslightly widerthanhigh.Theneuralcanal,markedlylesstrifoliate that in anteriorview, is higher thanwide; it is notice-ablysmallerthanthecondyle.Ashallowmedianridgeis presentontheﬂooroftheneuralcanal.Thezygantrumis slightlynarrowerthanthecondyle;itshowsoblique, well-developedarticularfacetsandapairoflargeintrazygantral foramina.Therearenoparazygantralforamina.Theneural spineiswelldifferentiatedfromthepostzygapophyses,i.e., theposteriormarginoftheneuralarchbetweentheneural spineandeachpostzygapophysisismarkedlyconcave.

Inlateralview(Fig.1C,H,M,R),thevertebraappears ratherelongate,witha moderatelyelevatedneuralarch. The neural spine is restricted to the posterior half of theneuralarch;itsobliqueanteriorborderrisessteeply. The paradiapophyses are large; they are anteroposteri-orlybroadanddorsoventrallytall.Thejunctionbetween the diapophyseal and parapophyseal articular facets is markedbyaslightconstriction;theparapophysealfacet islargerthanthediapophysealfacet.The interzygapophy-seal ridgeis salient and dorsallyconcave; small lateral foramina are present ventral to this ridge. The axis of the cotyle–condyle system is slightly oblique (i.e., the cotyleandthecondyleareorientedslightlydownwardand slightlyupward,respectively).Theventralmarginofthe centrumisconcaveandbearsashallowhaemalkeel.

Indorsal view(Fig.1D, I,N, S),the interzygapophy-seal constriction is well marked. The width across the prezygapophyses is slightly greater than across the

postzygapophyses. The neural arch shows a weak parasagittal bulge oneach side ofthe baseof the neu-ralspine.Theposteriormarginoftheneuralarchforms a broadconcavity,withoutadistinctmediannotch.The zygospheneshowsagentlyconcaveanteriormarginanda slightanterolateraltruncation.Theobovate prezygapophy-sealarticularfacetsareacuteanterolaterally.Thereareno prezygapophysealprocesses.

In ventral view (Fig. 1E, J, O, T), the centrum is subtriangular; its lateralmargins are markedly concave lateroposteriorly. Theshallow, ridge-likehaemalkeel is wellmarked;itoriginatesanteriorlyfromnearthe coty-lar rim and extends posteriorly to the condyle, where it forms a smalltubercle.A pairof subcentralforamina is present. The paradiapophysesare large, with antero-posteriorlywell-developedparapophysealarticularfacets reachingthecotylarrim(i.e.,noparacotylarnotchesare present).Thepostzygapophysealarticularfacetsare obo-vate,i.e.,longerthanwide.

4. Discussion

Lapparentophiids are rare mid-Cretaceous terrestrial snakesthatareknownonlyfromafewisolatedvertebrae. Lapparentophisdefrennei (andthefamily Lapparentophi-idae)waserectedonthebasisofthreetrunkvertebraefrom the?uppermostAlbian–CenomanianofInAkhamil,

Alge-ria(Hoffstetter,1959).Thisspeciesissigniﬁcantlylarger

than Lapparentophis ragei and is characterized by more massivelybuilttrunkvertebrae(Fig.2).Are-examination ofthetypematerialofLapparentophisdefrenneihas con-ﬁrmed that no parazygosphenal foramina are present, unlikeinL.ragei;inaddition,prezygapophysesaremore extended laterally,withmoredeveloped prezygapophy-sealarticularfacets;theneuralarchbearsawell-developed bulgeposteriortotheprezygapophysealarticularfacets; paracotylarnotchesarepresent;thezygospheneismore truncatedanterolaterally;theinterzygapophysealridgeis lessmarked;thecentrumismorerobust;theaxisofthe cotyle–condylesystemislessoblique;andthehaemalkeel islessmarked(Fig.2).

Threeotherisolatedvertebraefromthemid-Cretaceous ofNorthAfricaweretentativelyassignedto Lapparentophi-idae(oridentiﬁedasbelongingtolapparentophiid-grade snakes). A single,poorlypreserved vertebra wasbrieﬂy describedfromtheuppermostAlbianofElKohol,Algeria (Cunyetal.,1990).Thisincompletespecimen, consisting

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Fig.2. ComparisonoftheholotypetrunkvertebraeofLapparentophisrageisp.nov.(A–E)andL.defrennei(F–J)inanterior(A,F),posterior(B,G),leftlateral (C,H),dorsal(D,I),andventral(E,J)views.LinedrawingsofthevertebraofLapparentophisdefrenneiafterHoffstetter(1959:ﬁg.2a).Scalebar:5mm.

Fig.2. Comparaisondesvertèbresdorsales(holotypes)deLapparentophisrageisp.nov.(A–E)etL.defrennei(F–J)envuesantérieures(A,F),postérieures (B,G),latéralesgauches(C,H),dorsales(D,I),etventrales(E,J).DessinsdelavertèbredeLapparentophisdefrenneid’aprèsHoffstetter(1959:ﬁg.2a).Barre d’échelle:5mm.

only of the centrum,is about half thesize of the Kem Kem specimens described here. In ventral view, it is similarinshape tothecentrumofLapparentophisragei; however, in the El Kohol vertebra, the lateral margins of the centrum are more inﬂated and the haemal keel is wider and less sharp (Cuny et al., 1990: ﬁg. 1). In addition, two isolated vertebrae representing two dis-tinct?Lapparentophiidae(“lapparentophiid-gradesnakes AandB”)weredescribedfromtheCenomanianofWadi Abu Hashim, Sudan (Rage and Werner, 1999; Werner

andRage,1994).Thelapparentophiid-gradesnakeAfrom

Wadi Abu Hashim, which may represent a new genus and species according to Rage and Werner (1999), is known from a single small trunk vertebra, wider than long.ThisformissimilarinsizetoLapparentophisragei; however, it canbe distinguished fromthe latter by its less elongatevertebrae,itshigherneuralarch,itswider and blunterhaemalkeel,andtheabsenceofboth para-cotylarandparazygosphenalforamina(RageandWerner, 1999: ﬁg. 2). The lapparentophiid-grade snake B from WadiAbuHashimisonlyrepresentedbyasmall(2.7mm long),elongatecaudalvertebraand,therefore,cannotbe compared witheither of the Kem Kem trunk vertebral specimens. The generally accepted Cenomanian age of the WadiMilk Formation, which yielded a rich assem-blageofsnakes(includingthetwolapparentophiid-grade forms A and B discussed above) and other vertebrates atWadiAbuHashim(Rauhut,1999;Werner,1994),has recently been challenged based on palynological data

(Eisawi,2015)anddetritalzircongeochronology(Owusu

Agyemang et al., 2019).These two studies suggested a

Campanian–Maastrichtian age for this formation. How-ever,thepalynological datapresented byEisawi (2015)

arefromtheShendiFormation,asupposedlateral equiva-lentoftheWadiMilkFormation,andthusdonotprovide a direct age estimate for the Wadi Abu Hashim verte-brateassemblage.Similarly,thesixLateCretaceouszircon grainsreportedbyOwusuAgyemangetal.(2019)come

fromthe Jebelel Gamman region, whileno Cretaceous zirconswerefoundintheWadiAbuHashimregion.In addi-tion,theﬁvepotentiallyage-constraininggrainssuggesting a maximum depositional age of 79.2_±2.4 Ma (middle Campanian)comefromfoursandstonesamplesthat cor-respondtofourdistincthorizonsdistributedthroughthe upperand lower membersof theWadiMilkFormation

(Owusu Agyemanget al., 2019: ﬁgs. 3 and 7).

Accord-ingtoDickinsonandGehrels(2009)andRossignoletal.

(2019),suchresultsshouldbeconsiderednotstatistically

robust.Furthermore,the occurrenceof somevertebrate taxa(e.g.,distobatidsharks;VulloandNéraudeau,2008) in the WadiAbu Hashim assemblage is not consistent with a post-Cenomanian age. For these reasons, the Sudaneselapparentophiid-gradesnakesdescribedbyRage

andWerner(1999)arestillregardedhereasCenomanian

inage.

Pouitella (type and only known species: P. pervetus

Rage,1988),fromtheearly–middleCenomanianof

west-ernFrance(holotypeandonlyknownspecimenfromBrézé andstillundescribedmaterialfromLussant;seeCunyetal., 1990),isapoorlyknownbasalsnakeshowingageneral morphologyandalevelofevolutionsimilarto Lapparen-tophis(Rage,1988).ThisledRage(1988)toprovisionally placePouitellawithinLapparentophiidae.Thisplacementis herereinforcedbythepresenceofparazygosphenal foram-inainLapparentophisragei,anunusualapomorphicfeature alsoobservedinPouitellapervetus(Rage,1988)and oth-erwiseknownamongsnakesonlyintwoorthreelatest Cretaceousmadtsoiids(Ladukeetal.,2010)andinafew post-Cretaceoustaxa(Head,2005;McCartneyetal.,2018;

Rage,1983,2001,2008;Rageetal.,2003,2008).Pouitella

isthereforeconﬁrmedasamemberofLapparentophiidae, thusrepresentingtheonlyknownoccurrenceofthisfamily inLaurasia.ThissuggeststhatadispersaleventfromAfrica toEuropemayhaveoccurredinlapparentophiidsnakes, whichisconsistentwiththepresenceofseveralother ver-tebratetaxawithGondwananafﬁnitiesintheCenomanian

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ofwesternEurope(seeCsiki-Savaetal.,2015;Vulloand

Rage,2018).

Acknowledgments

IwarmlythankNour-EddineJalilforprovidingMHNM collectionnumbers,DamienGendryforhishelpwiththe photographsofthespecimens,andMarcPoujolfor use-ful discussion on detrital zircon geochronology. I wish to thank Nathalie Bardet for her editorial assistance, andMichaelCaldwell,JamesGardnerandananonymous reviewerfortheirconstructivecommentsthatimproved themanuscript.Finally,Iamdeeplyindebtedtomylate friendandcolleagueJean-ClaudeRageforveryuseful dis-cussions,andforhiscontinuousand mostvaluablehelp inexaminingandinterpretingfossilmaterialfromvarious localitiesduringthelasttwodecades.

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