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A large skull of Ichthyosaurus (reptilia: Ichthyosauria) from the Lower sinemurian (Lower Jurassic) of Frick (nW switzerland)

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A large skull of Ichthyosaurus (reptilia: Ichthyosauria) from the Lower sinemurian (Lower Jurassic) of Frick (nW switzerland)
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  AbstrActA iomplee kull of a ihhyoau aiued o  Ichthyosaurus communis   C onybeare 1822 i epoed fom he Lowe siemuia alaeie (uppepa of he “beie Meme”, peviouly “Aieekalk”, semioaumzoe) of Fik (cao Aaau, ohe swizelad). I i he fi eod of hi eu ad peie i swizelad, ad he fi defiie eod of he e-u  Ichthyosaurus fom eal Euope. thi peie wa hiheo oly kowfom Lowe Heaia o Lowe siemuia depoi of Elad ad Up-pe siemuia edime of belium. the peime epee a paiulalylae idividual ha oidealy exeed all kow Elih epeeaiveof hi peie i kull leh, ad i loe i ize o he ile peime fombelium. Uuual aaomial feaue ilude a o ooifiaio of hepoeio kull-oof oe (poaly a eul of a old ooeei ae) ada vey eloae ad deep exavaio ieaali. A ho oveview of ua-ial swi Meozoi ihhyoau fid i povided. the Juai eod appeavey pahy o fa, u ha ee oidealy impoved hak o ee di-oveie.ZUsAMMEnFAssUngDe uvollädie shädel eie Ihhyoauie i sedimee de Ueesiemuium (oee shihekomplex de “beie-Meme”, ila“Aieekalk”, emioaum-Zoe) vo Fik, Kao Aaau, shweizwid  Ichthyosaurus   communis   C onybeare , 1822 zueode. Diee A waihe u au dem Heaium ud Uee siemuium vo Elad uddem Oee siemuium vo belie eka. E hadel ih um de e-e nahwei diee taxo i de shweiz ud um de ee defiiivenahwei de gau  Ichthyosaurus i Mieleuopa üehaup. Da Ex-empla eiz eie eome göße, die die alle elihe Exemplae weiüeiff ud dem eizie Fud au belie ahe komm. Uewöhliheaaomihe Mekmale id ue adeem die ake Kooifikaio depoeioe shädeldahelemee, die vemulih duh da hohe ooee-ihe Ale de tiee edi i, owie eie eh lae ud iefe Exavaioieaali. Ei kuze Üelik de meozoihe Ihhyoauiefude deshweiz zei, da ieodee de juaihe Foileih ila eh u-vollädi i, ih ae i de leze Jahe duh eue Fude eählihveee ha. Introduction the foil eod of ihhyoau i swizelad i exeive,pai mo of he Meozoi (Fi. 1). numeou well-pe-eved keleo of ix diffee ihhyoau eea have eedioveed i he Middle tiai  fossillagerstätte of Moe sagioio (e.. sade 1989; Maih & Mazke 1997a, , 2000a;bikma 1998a, , 2004; Maih e al. 2006).   Fom he LoweMuhelkalk of cao Aaau, Huee (1916) ad callaway &Maae (1989) diued iomplee Middle tiai (Aiia)peime of mixoauid ad poile ymopodylid.Maih & Mazke (2005) eely deied a fameaykull peime of he mixoauid Phalarodon major  fom heAiia of Aaau. the Lowe Juai ihhyoau fid fomswizelad wee ummaized y Maih & reidof (2006a,). Lowe Juai ihhyoau ilude a omplee keleoof  Stenopterygius longifrons fom he Lowe toaia of tey-ahaux (Huee 1939), wo iomplee kull of Ealy toa-ia ae fom he saffele, a omplee kull fom he Lowetoaia of Auel (e.. Maih & reidof 2006a, ), a ompleekull ad ome aoiaed poaia of  Leptonectes tenuiros-tris ha wa eely dioveed i Uppe Plieahia depo-i a Ue Haueei (Maih & reidof 2006a, ; Wezel& reidof 2007), ad a fameay ideemiae peimewa deied y Weidma (1981) fom he Lowe toaia ahe rieau de chalevay ea Moeux. I addiio, umeoufid a vaiou loaliie fom he rhaeia (Kuh 1951; cal-laway & Maae 1989; Meaux & Moh 1989; Fue 1993;H. Fue , pe. omm. 2006), Lowe, Middle ad Uppe Jua-i (e..   Peye & Koehli 1934; de bok e al. 2004 ) ae ill A lae kull of   Ichthyosaurus (repilia: Ihhyoauia) fom he Lowesiemuia (Lowe Juai) of Fik (nW swizelad) M iChael W. M aisCh   1 , a ChiM G. r eisdorf   2, *, r udolf s Chlatter   3 & a ndreas W etzel   2 Key words:    Ichthyosaurus communis , Ihhyoauia, kull, Lowe Juai, siemuia, swizelad 1661-8726/08/030617-11DOI 10.1007/00015-008-1299-4bikhäue Vela, bael, 2008swi J. geoi. 101 (2008) 617–627 1 Iiu ud Mueum fü geoloie ud Paläooloie, siwaae 10, D-72076 tüie, gemay. 2 Uiveiä bael geoloih-Paläooloihe Iiu, beoulliae 32, cH-4056 bael, swizelad. 3 naukudemueum Leipzi, Loziae 3, D-04105 Leipzi, gemay.*coepodi auho: A.g. reidof. E-mail: ahim.eidof@uia.h  Ichthyosaurus fom he siemuia of swizelad 617  618 M. W. Maih e al. udeied. Aye (2003) evealed a ceaeou (Apia) e-od wa fom La Pea (cao de neuhâel). Fo he akeof ompleee, we hall meio a o ye pepaed oumof a ill udeemied ihhyoau, oed i he sauiemu-eum Fik ie 2006, dioveed ewee siel ud rhei-felde (cao Aaau) i edime of he rhie. boe adeeh ae emedded i oeio wih hih pyie oe of ukow aiaphial oii (Lowe Juai?).I hi pape, aohe impoa swi Juai ihhyoaufid i deied. the epoed kull, poile i fame adveeae (houed i he sauiemueum Fik), wee foud aFik (cao Aaau, ohe swizelad; Fi. 2), y HaHama i 1999. Depie hee ihhyoau emai wee ol-leed fom ee, hei aiaphial poiio a e peielydaed o he Ealy siemuia (Ealy Juai). the epoedihhyoau i he fi uaial peime fom hi ae iswizelad, ad oe of he few diaoi ihhyoau pei-me fom he siemuia i oieal Euope. Geological Setting the Lowe Juai edime of ohe swizelad ae 25o ome 70 m hik (e.. bau 1920; Keleo 1944; Mülle eal. 1984), ha i oidealy le ha i he adjae aea of gemay ad Fae (e.. Dead-Paad 1984; soll-seffa1987; bloo e al. 2005; shmid e al. 2008). the Lowe Juaidepoi maily oi of mud- ad maloe, alaeiead limeoe ei iealaed. Fequely odeaio,hiaue ad aup faie hae ou wihi a ho di-ae (e.. Ei 1910, 1926; bue 1952; Joda 1983).the Fik eio i udivided aodi o he oepof he «saffele Fomaio» (Fi. 3). the “saffele Foma-io” i popoed o e ued fo he Ealy Juai edimei ohe swizelad ha have hiheo ifomally eeummaized a he “Lia” (Joda e al. 2008). Alhouh heswi commiee fo saiaphy aee wih he oep, he« saffele Fomaio » ha o e fomally iodued yewhile upulihed.A Fik, i oa o ohe loaliie i swizelad, moof he Lowe Juai i expoed i a lay pi (Meye & Fue1995). thi eio expoe edime of he Lowe Heaia(Liaiu zoe) o he Lowe toaia (Falife zoe) ad iaou 30 m hik (shlae 1975; W. Ee, pe. omm. 2006;ow daa). the Fik loaliy i famou fo umeou fid of keleal emai of poauopod dioau eloi o Pla-teosaurus ad aoiaed faua (e.. galo 1986; sade 1990,1992; Hui 2008) oui i eeial noia mudoe(= “Oee seimeelkeupe” of he “seimeelkeupeFomaio” eu Ezold & shweize 2005). the tiai de-poi ae ovelai y maie Lowe Heaia iumioumal (Fi. 3: laye 1 o 9; “shamele Meme”, peviouly“Iekemeel”; ee Joda e al. 2008).Hihe i he eio, a a. 4 m hik equee i domiaedy alaeie; i i of Lae Heaia o Lae siemuiaae (Aulaa zoe o Ouum zoe) ad epee he“beie Meme” (peviouly kow a he “Aulae-hihe” ad he “Aieekalk”; ee Joda e al. 2008). thehihly foilifeou ueio of laye 10 o 15, Lae Hea-ia o Ealy siemuia i ae (Aulaa zoe o semioa-um zoe; Fi. 3), ha evealed may diaiulaed ihhyoauemai (e.. i ad veeae; sade 1990; Meye & Fue1995; Maih & reidof 2006a, ; H. Hama, P. Völi, pe.omm. 2004).Fo he ae deemiaio of he epoed ihhyoau e-mai, oh he lihofaie ad he mode of weahei of helaye 14 o 16 of he Fik eio (= semioaum zoe; Fi. 3)ae of ea iifiae. Laye 14 i aou 50 m hik adoi of quie eia alaeie ih i ewoked pho-phoiized mould of iveeae ( Gryphaea , Plagiostoma , Cardinia,   Oxytoma ) ad phophai pele (e.. bue 1952: Fi. 1. Ouadi ihhyoau fid fom swizelad. a, Laufeu/Ag(Huee 1916); , shwadeloh/Ag (Moeh 1857; Maih & Mazke 2005);, Moe sa gioio/tI (e.. bikma 2004); d, Fil da sidie (beü)/gr (Fue 1993); e, naioal Pak eio (Zeez)/gr (Fue 1993);   f,ramoz (Aoa)/gr (Fue 1993);   , Alpliho (Davo)/gr (Fue 1993);   h, sheaplaa (Päiau)/gr (Fue 1993); i, Pla Falo (Yvoe)/VD(Meaux & Moh 1989; h. Fue , pe. omm. 2006); j, beie/sH (Füh1962); k, Fik/Ag (hi pape); l, Ue Haueei/sO (Maih & reidof 2006 a,); m, saffele/Ag (Maih & reidof 2006 a, ); , Auel/JU (e..Maih & reidof 2006a, ); o, teyahaux/Fr (e.. Huee 1939) ad ri-eau de chalevay/Fr (Weidma 1981); p, buke/bL (de bok   e al. 2004 );q, Omalie/bL (de bok   e al. 2004 ); , bo (ruppoldie) s Ole/sO(Peye & Koehli 1934; naumueum Ole, [eie ume nMO 20141o 20216 Paläooloihe Iiu ud Mueum de Uiveiä Züih[eie ume PIMUZ A/III 0863]; , gellie/bL (Peye & Koehli1934); , La Pea/nE (Aye 2003).Fi. 2. Map of ohe swizelad, wih he poiio of he foilifeou lo-aliy of Fik (bE: be; bs: bael; ZH: Zuih; modified afe Wezel &Allia 2000).   Ichthyosaurus fom he siemuia of swizelad 619 Fi. 3. Deailed eio of he Lowe Heaia o Uppe siemuia aa (Liaiu o Ouum zoe) a Fik. Aeviaio: O.t., Ouu-to;   b., buk-ladi zoe; ?, ueai ioaiaphial affiliaio. 1: u-ae eu Ulih (1977); 2, Meme afe reidof e al. i Joda e al. (2008); 3, Meme euMülle e al. (1984); 4, ammoie zoe eu Dea e al. (1961) ad eu bloo (1979); 5, poiio of he ouday ewee Uppe Heaia ad Lowesiemuia eu   Hoffma (1934), Wallie (1956a, ) ad shlae (1975); 6, “ Schlotheimia f. extranodosa ” (shlae 1975: 86 ); 7, eviio of “ Psiloceras  ( Caloceras ) f.  johnstoni ( s oW .)” (shlae 1975: 76 ). +++++++++++ 02543198761710111213141516181920222324252126    H  e   t   t  a  n  g   i  a  n   S   i  n  e  m  u  r   i  a  n Norian    I  n  s  e   k   t  e  n  m  e  r  g  e   l    A  n  g  u   l  a   t  e  n  -  s  c   h   i  c   h   t  e  n    L  a   t  e   E  a  r   l  y   L  a   t  e   E  a  r   l  y O.T. R eisdorf  2004-2006 Ammonites    A  r   i  e   t  e  n   k  a   l   k    C   l  a  s  s .  a   f   t  e  r   D   u  n   h  a  m    (   1   9   6   2   )   L   i   t   h  o   l  o  g  y   W  e  a   t   h  e  r   i  n  g  p  r  o   f   i   l PGBMW    5   0  c  m   M  a  c  r  o   f  o  s  s   i   l  s   L  a  y  e  r   i  n   d  e  x Section Frick (Grube Gruhalde, Tonwerke Keller AG, Frick/ AG); coord.: 643.000 / 261.900 02543198761710111213141516181920222324252126    S  u   b  -  s   t  a  g  e    1    M  e  m   b  e  r    3    S  c   h  a  m   b  e   l  e  n   M   b . FrickMb.    B  e  g  g   i  n  g  e  n   M   b .    M  e  m   b  e  r    2        5    S   t  a  g  e    O   b   t  u  s  u  m   S  e  m   i  c  o  s   t  a   t  u  m   B  .    A  n  g  u   l  a   t  a   L   i  a  s   i  c  u  s    ?    4    A  m  m  o  n   i   t  e  z  o  n  e      P  s   i   l  o  c  e  r  a  s   (   C  u  r  v   i  c  e  r  a  s   )  s  u   b  a  n  g  u   l  a  r  e    (   O    P   P  .   )   ?    P  s   i   l  o  c  e  r  a  s   (   D   i  s  c  a  m  p   h   i  c  e  r  a  s   )  m  e  g  a  s   t  o  m  a    (   G     Ü   M   B   E   L    )    P  s   i   l  o  c  e  r  a  s   (   C  a   l  o  c  e  r  a  s   )   h  a   d  r  o  p   t  y  c   h  u  m    n .   f .   W     Ä   H   N   E   R    P  s   i   l  o  c  e  r  a  s   (   C  a   l  o  c  e  r  a  s   )   t  o  r  u  s   c   f .   c  o  n  v  o   l  u   t  u  m     (   S    I   M   P   P   S   O   N    )    P  s   i   l  o  c  e  r  a  s   (   C  a   l  o  c  e  r  a  s   )   c   f .    h  e  r  c  y  n  u  m     (   L    A   N   G   E    )    A   l  s  a   t   i   t  e  s   l  a  q  u  e  u  s    (   Q    U  .   )    A   l  s  a   t   i   t  e  s   s  p .   "    S  c   h   l  o   t   h  e   i  m   i  a   c   f .   e  x   t  r  a  n  o   d  o  s  a    "    S  c   h   l  o   t   h  e   i  m   i  a   c   f .   s   t  e  n  o  r   h  y  n  c   h  a   v  a  r .   a   l   t  a    L    A   N   G   E    S  c   h   l  o   t   h  e   i  m   i  a   d  e  p  r  e  s  s  a    (   W     Ä   H   N   E   R    )    P  r  o  m   i  c  r  o  c  e  r  a  s   s  p .   i  n   d .    A  r  n   i  o  c  e  r  a  s   f  a   l  c  a  r   i  e  s    (   Q    U  .   )  c   f .    A  r  n   i  o  c  e  r  a  s  o  p  p  e   l   i    (   G    U    É   R   I   N   -   F    R   A   N   I   A   T   T   E    )    P  s   i   l  o  c  e  r  a  s   s  p .   i  n   d  e   t .    S  c   h   l  o   t   h  e   i  m   i  a   s .   l .    S  c   h   l  o   t   h  e   i  m   i  a   c   f .   s   i  m   i   l   i  s    (   S    P   A   T   H    )    S  c   h   l  o   t   h  e   i  m   i  a  a  n  g  u   l  a   t  a    (   S    C   H   L  .   )    S  c   h   l  o   t   h  e   i  m   i  a   (   A  n  g  u   l   i   f  e  r   i   t  e  s   )  a  n  g  u   l  o  s  a    (   L    A   N   G   E    )    S  c   h   l  o   t   h  e   i  m   i  a   c   f .   p  s  e  u   d  o  m  o  r  e  a  n  a    (   S    P   A   T   H    )    A  n  g  u   l  a   t   i  c  e  r  a  s   s  p .   i  n   d  e   t .    C   h  a  r  m  a  s  s  e   i  c  e  r  a  s   s  p .   i  n   d  e   t .    S  c   h   l  o   t   h  e   i  m   i  a  m  o  n   t  a  n  a    (   W     Ä   H   N   E   R    )    C  u  r  v   i  c  e  r  a  s   s  p .   i  n   d  e   t .    A  s   t  e  r  o  c  e  r  a  s   (   A  s   t  e  r  o  c  e  r  a  s   )  o   b   t  u  s  u  m    (   S    O   W  .   )    A  s   t  e  r  o  c  e  r  a  s   c   f .   s   t  e   l   l  a  r  e    (   S    O   W  .   )    P  r  o  m   i  c  r  o  c  e  r  a  s   c   f .   p   l  a  n   i  c  o  s   t  a    (   S    O   W  .   )    A  s   t  e  r  o  c  e  r  a  s   s  p .    P  a  r  a  c  o  r  o  n   i  c  e  r  a  s   s  p .    A  r  n   i  o  c  e  r  a  s   s  p . 6 7  belemnitesnautilidsbioclastsammonitesbed rich in gryphaeansbed rich in Cardinia and Plagiostoma bituminous marly claysmarlstonesilty marlstonemarly limestonelimestonephosphoritephosphoritic nodulespyrite + bioturbated nodule/surfacefish remainscrinoidspelecypodsgastropodsbrachiopodsichthyosaur remainsgryphaeansbrittle star   Acrodus nobilis  A GASSIZ 1838(see Kindlimann 1990)insect remainsundifferentiated bioclastsplant remainsammonite (in place)ammonite (approximate strati-graphic position known) Ichthyosaurus communis C ONYBEARE 1822  620 M. W. Maih e al. eio 16; gell 1968; shlae 1975; Meye & Fue 1995).the 10 o 20 m hik laye 15 oai appaely lihly leaoae ad le ewoked phophoii pele ad mao-foil, u exhii a imila lihofaie (Pee 1964). I i leeia aai eoio a he laye 14 ad 16. Laye 16 iaou 50 m hik ad oai le maofoil ha he u-delyi laye, alhouh i i liholoially imila. Alhouhhe epoed peime wee eieved fom ee ad weeo aoiaed wih daale ammoie, hei aiaphialpoiio ha ee eoued wih eaiy y a deailedio- ad lihoaiaphial aalyi, ad he peee of hehaaeii phophoii faie ad he eoio ehaviou of laye 15 (Fi. 3). the ioaiaphial ae of he ho aumha ee ideified a semioaum zoe (Ealy siemuia). Systematic Palaeontology Ode Ihhyoauia de b lainville 1835Family Ihhyoauidae b onaparte 1841geu  Ichthyosaurus   de   la b eChe & C onybeare 1821type peie  Ichthyosaurus   communis   C onybeare 1822  Ichthyosaurus communis C onybeare 1822 (Fi. 4–7) Material. – A iomplee kull (sMF 46), a poile i fa-me (o he la of sMF 46), wo omplee ad a hid fa-meay veea (sMF 66). the peime ae houed i hesauiemueum Fik (swizelad). Emended diagnosis. – Lae peie, kull eahi moeha 600 mm i leh, ou ad modeaely lo ou(aio leh of ou o leh of jaw 0.57–0.69), modeaelylae oi (aio of oi leh o jaw leh 0.20–0.28, uuually < 0.25), le ha 20 maxillay eeh, ou ad uvedeeh, wih lu ip, oo eve auply expadi, laimalwih eomou aeio exeio elow pemaxilla, jual wihouded o-eio, quadaojual modeaely ho doo-veally, eahi dow diily elow wo hid he oialheih, quadae aedi plae ou, o a hi lamia a i  Ichthyosaurus intermedius ( modified fom   Mgowa 1974 adMaih & Mazke 2000a). Description. – the kull of   Ichthyosaurus communis haee deied i deail y vaiou auho (oaly y sol-la 1916; Mgowa 1973; wih addiio y godefoi 1996;Maih & Mazke 2000). theefoe, he pee deipiofoue o he impoa ad uuual feaue.the peime i ill emedded i he ok, i a la a.700 × 500 mm i ize (Fi. 4). Mo of he ou i mii, uhe aial eio i peeved o he ih ide (Fi. 5). thedoal ad pa of he ih a well a lile of he lef laealufae of he kull have ee pepaed (Fi. 4–6). some ad-diioal kull eleme ad eveal eeh, whih have deahedfom he majo pa of he kull, ae pead ove he la adhave ee paially pepaed a well (Fi. 4). Exep fo a po-ile i fame hee ae o emai of he poaium.two omplee ad a hid fameay veea wee fouddimemeed loe o he aium (Fi. 7). thei ize fi o haof he kull. they vey likely deive fom he ame peimead ae, heefoe, iefly deied ad fiued hee.A majo poio of he aium ha udeoe oide-ale dooveal dioio. nevehele, i eai muh of i hee-dimeioal uue. the peoial poio of hekull ha uffeed mo fom oh dioio ad weahei,ad uue ae i pa had o follow. the oial ad poo-ial poio ae, i oa, vey well peeved.Pa of he poeio poio of oh pemaxillaie aepee, u oly damaed. O he ih ide, he pemaxillafom a aih uue wih he aal aeio o he ai adalo fom he aeio ode of he ai (Fi. 5). the poe-u upaaiali i oke off, u i i ill well peeved adexed alo he veal mai of he ai fo aou 40 mm,almo eahi he poeio mai of ha opei. I i ve-ally uued o he laimal fo i eie leh. thee a paof he pemaxilla i oke expoi he udelyi laimal,whih exed aeioly almo o he level of he aeio a-ial mai (Fi. 5). Veally, oh laimal ad pemaxilla ae Fi. 4. Iomplee kull of   Ichthyosaurus   communis C onybeare 1822 (sMF46), i doal view. a) Phooaph. ) Iepeaive keh. Aeviaio:?, poile i; d, eeh; eo, exoipial; l, laimal; , aal; p, paieal; pmx,pemaxilla; pof, pofoal; p, peyoid; q, quamoal; , upaempoal.sale a: 100 mm.   Ichthyosaurus fom he siemuia of swizelad 621uued o he maxilla aeio o ad elow he exeal a-i. Oly he doalmo poio of he maxilla i expoed. thepoaial poio of he laimal i oly expaded doallyad poeoveally, whee i fom a poe aou 40 mm ileh (o ompleely pepaed poeioly) ha ook pa ihe uoial ah ad veal mai of he oi. Doal ohe oii of hi poeoveal poe, he laimal i poe-ioly oveed y he deedi lamia of he pefoal, wihwhih i fom a aih, aeodoally aedi uue. Do-ally, a ovex oa wih he aal i ealihed. A he ju-io of aal, pefoal ad laimal a maive ak aveehe oe ad mak he uue.the pefoal i oly lile expoed alo he aeodo-al ad doal oial mai (Fi. 4–6). I deedi flaei exeive ad fom mo of he aeio oial mai. Iexpoue o he kull oof i oly 15 mm wide a maximum.A deep ouh i fomed alo he aal-pefoal uue(Fi. 5). I pa i mih e a peevaioal aifa aued ydooveal ompeio.the pofoal i iomplee o he ih ide, u om-plee o he lef ide (Fi. 4 & 6). I fom he poeio half of he doal oial mai. the oa wih he pefoali ulea, due o iomplee peevaio. I i ovelappedy he aal aeioly. A he poeiomo poio of ohaal ae lihly damaed, pa of he udelyi pofo-al have ee expoed i plae. the uue ewee aalad pofoal i oly eae i i laeal half, u moeo le ely oave medially. I ed aou 55 mm medialo he oial mai o he lef ide. A hi poi, he po-foal fom a ho, aih uue wih he foal. thiuue how o majo ovelap ewee he oe o eiheide.Poeioly he pofoal i uued o he paieal. theuue exed fom a poi loe o he aeolaeal oe of he empoal feea i a aeomedial dieio fo a lehof aou 45 mm efoe he paieal oa he foal. theamou of ovelap ewee pofoal ad paieal aai ap-pea o have ee limied. Howeve, he ufae of he oelealy idiae ha a poeio hee of he pofoal haovelapped he aeiomo poio of he paieal wa oii-ally pee. the poio of he pofoal iuaed eweehe aal aeioly, paieal poeioly ad foal mediallyi oly 15 mm wide medially. the poeolaeal poio of hepofoal ake pa i he fomaio of he aeolaealmai of he empoal feea. tha mai i fomed y hepofoal fo a leh of aou 35 mm o he lef ide. Fuhepoeioly, he pofoal i eplaed y he aeio poeof he upaempoal. the aeiomo 25 mm of hi poeae ill aahed o he pofoal o he lef ide (Fi. 4). thewo oe fom a vey ih, almo loed uue. Whehehee wa a medial lamella of he pofoal ovei he i-e wall of he upaempoal aeioly i ueai, due oiomplee pepaaio.the aal ae exeive eleme. they fom mo of hedoal kull oof up o he level of half oial leh (he lehof he oi a e aumed o have ee aou 200 mm fomompaio o ohe, moe omplee peime). speial ae-io mu e ive o he expeio of he exavaio ieaa-li i he pee peime, whih i, i fa, a opiuou, deep,ouh-like uue ha exed fo a oideale leh e-wee he aal ad foal ad i, heefoe, emed he foaaofoali hee (Fi. 4 & 6). I mu e oed ha ome of he uue deied mih e lihly oveexaeaed dueo dooveal ompeio ad a euli peadi of heaal. Mo of he uue, iludi he ieaal foamead he deep foa ha exed almo o he foame paiealewhih follow i poeioly ae, howeve, defiiely euie.Fom he level of half he leh of he exeal ai, of whih he aal fom he doal mai, he foa aofoalia a a aow oove ewee oh aal. Aeioly, i ioly 2 mm wide ad vey hallow, u a he level of he po-eio mai of he ai i ha expaded o a widh of 5 mmad ha deepeed oidealy. sholy ehid he level of heaeio oial mai, he oove expad aai o a widh of ow 10 mm. I fa he wo aal looe oa ad eloe afoame ieaale aou 30 mm i leh ad 10 mm i widh.the laeal mai of he foame eem o e ia, o heei o evidee ha i i a aifiial uue. the laeal wallof he foa aofoali ae ill fomed y he aal, whihule oidealy doally o oh ide, o ha he midlie Fi. 5. rih iumaial eio of he kull of   Ichthyosaurus communis   C onybeare 1822 (sMF 46). a) Phooaph. ) Iepeaive keh. A-eviaio: l, laimal; mx, maxilla; , aal; pmx, pemaxilla; pf, pefoal.sale a: 50 mm.
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