early ordovician conodonts from the southern cuyania terrane

EARLY ORDOVICIAN CONODONTS FROM THE SOUTHERN CUYANIA TERRANE (MENDOZA PROVINCE, ARGENTINA) OLIVER LEHNERT, MARTIN KELLER , and OSV ALDO BORDONARO

Lehnert, D., Keller, M., and Bordonaro, D. 1998. Early Ord ovician co nodo nts from the southern Cuyan ia terrane (Mendoza Prov ince, Argentina) . In: H. Sza niawski (ed.), Procee dings of the Sixth Europea n Cono dont Sy mposi um (ECDS VI). - Palaeontologia Polonica 58, 47- 65. Lower Ordo vician do lomites and limestones of the Ponon Trehue Form ation (Mendoza Province, Argentina) have been sampled for conodo nts . Th e docum ented co nodo nt faunas indicate a Late Tremadoc through Late Arenig age and are co mpara ble with those from the Precordillera to the north . Composition of the faunas and sedim entological feature s sho w that the two areas were connected and dem onstrate that the outcrops of San Rafael and the Precordill era are part of the same terran e. The faunas sho w a trend from Midcontinent shallow-water conodonts in the lower part of the succession to tempera te-water faunas in the middl e part. Pandemi c faun as, together with elements of the co ld-water group are present in the uppermost interva l of the Ponon Trehu e Form ation and mirror a remark able sea- level rise. Key w o r d s : Co nodo nta, biostratigraph y, paleogeo graphy, Early Ord ovician, Cuya nia Terrane , western Argentin a.

Oliver Lehnert [[email protected], Martin Keller [[email protected], Institut fur Geo logie und Mineralo gie, Universitiit Erlan gen, Schlossgarten 5, D-91054 Erlangen, Germany. Osvaldo Bordon aro, Centra Regional de Investigaciones Cientifi cas y Tecnicas (CRIC IT) , CC l3 I , 5500 Mendo za, Argentina. Recei ved 2 February 1997. acce pted 30 September 1997

48

OLlVER LEHNERT, MARTIN KELLER and OSVALDO BORDONARO

INTRODUCTION The Precordillera of San Juan, La Rioj a, and Mendoza and other outcrops of Early Paleozoic platform carbonates in western Argentina, together with the basement of the western Sierras Pampeanas, represent fragments of a Laurentia-derived "Cuyania Terrane" (RAMOS 1995). In the Precordillera, approx . 2 100 m thick tropical carbonate platform deposits (KELLER 1997) were deposited from the late Early Cambrian to the Early Llanvirn in a miogeoclinal setting . This terrane with its Cambro-Ordovician carbonate platform is unique in South America . It has a possible extension of 1000 km by 600 to 800 km (RAMOS 1995; K ELLER 1997). Geological Provinces of Northwestern Argentina

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Cuyania Terrane

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Fig. 1 A. Location of the "Cuyania Terrane " in western Argenti na (modified from K ELLER 1997). B. The study area (Fig. 2), south of the city of San Rafael, is marked by a star.

EARLY ORDOVICIAN CONODONTS FROM SOUTHERN CUYANIA T ERR AN E

49

RAMOS et al. (1986) pointed out strong sedimentological and faunal affinities between the Precordillera and the Appalachians. Con sequently, RAMOS et al. (1986) and RAM OS (1988) interpreted the Precordillera as an exotic terrane of possible Laurentian provenance. Recent inve stigations suggest that this terrane originated in the Ou achita embayment at the southern margin of Laurentia (DALLA SALDA et al. 1992a, b; DALZI EL et al. 1994; ASTINI et al. 1995, KELLER and DICKERSON 1996). In the study area (Figs 1, 2), cry stalline bas ement of Grenvillian age (RAMOS per sonal communication 1996) composed of siliciclastic metasediments, gneisses, and granitoids is exposed. North of the Ponon Trehue Creek, the se Prec ambrian rocks (Cerro La Ventana Formation, Fig . 2) are overlain by Lower Ordovician carbonates of the Ponon Trehu e Formation. South of the creek, the basal sedimentary succession con sists of Middle to Late Ordovician (Llanvirn- Caradoc) deposits dominated by siliciclastic s (Lindero Formation; Fig. 2). WICHMANN ( 192 8) was the first who compared the carbonates of the San Rafael area with Ordovician outcrops in the northern part of the Mendoza Province . Ordovician fos sils from San Rafael have been first described by NUNEZ (1962). BALDIS and BLASCO (1973) reported Llanvirnian to Caradocian ? trilobites. LEVY and NULLO (1975) de scribed Llanvirnian to Llandeilian brachiopods. Only one short paper (H EREDI A 1982) dealt with the occurrence of conodonts iPygodus anserinusi ; however, the sa mple loc alit y is not given in that paper. Other publications dealing with thi s area are those of PADULA (1951), CRIADO ROQUE and IBANEZ (1979), and NUNEz (1979). The purpose of thi s study is to document for the first tim e the conodont faunal success ion of a cr aton al part of the Cuyania Terrane. Additionally, the data indicate that sea-level changes in the San Rafael area were simultaneous with tho se known from the miogeoclinal setting to the north. Also, we discuss here the onlap of the carbonate s onto the craton and the strong conden sation of the carbonate sequence. Finally, the new dat a support the sugg estions of various authors that the terrane wa s derived from Laurentia. In the discus sion of faunal affinities we will follow the terminology of BAGNOLl and STOUGE (1991) for the paleogeographical distribution of Arenig conodonts. These authors distinguished five different groups in two major realms (Midcontinent, North Atlanti c) : a pandemic group, a cold water group (North Atlantic Province ), a warm water group (Midcontinent province), a temp erate water group, and a warm water China group (China and Korea endemics). The spec imens figured (IANIGLA PI 710-762) are deposited in the repo sitory "Paleontologfa de Invertebrados del IANIGLA" (lnstituto Argentino de Nivologfa, Glaciologfa y Cienci as Ambientales; Departamento de Geologfa y Paleontologfa) in Mendoza, Argentina.

Acknowledgements. - We thank Dr. Jerzy DZIK (Institute of Paleobiology, Poli sh Academy of Sciences) for his careful review and critical comments, whi ch improved the pap er significantly. The "Deutsche Forschungsgemeinschaft" is gratefully acknowledged for financing the research on the Cambro-Ordovician conodonts from the Argentine Precordillera and the San Rafael area by O. LEHN ERT (Le 867/2- 1) and the sedimentologic inve sti gations on the Early Paleozoic success ions by M. KELLER (Ke 470/2-2). We also grat efully acknowledg e the logi stic suppo rt provided by the Centro de Investigacion es Cientfficas y Tecni cas (CRICYT, Mendoza) and the " Museo Municipal de Historia Natural de San Rafael " .

THE SECTION AND THE CONODONTS The Ponon Trehue Formation has been recently redefined by BORDONARO et al. (1996). In its type section at Cerro Ai Sol (Fig. 2) , the succession was subdivided into 4 informal unit s. Striat odontu s prolificus (PI. 1: 1) has been obtained from a level 3 m above the base of the dolomites of unit I (sample CAS I - see Fig . 2). Unfo rtunately, sample CAS 2 from the thick-bedded dolomites which form the upper part of this ba sal unit yielded brachiopod fragments only. No data were obtained from unit 2 composed of biolaminites and microbial boundstones. The dolomites and microbial carbonates of the two basal units represent deposits of a peritidal environment. In unit 3 of the Ponon Trehue Formation , different lithologies and open-marine macrofaunas are present. S. prolificus (PI. 1: 2-4, 7, 8), Colaptoconu s quadraplicatus, and Eucharodus parallelus (PI. 1: 5 ) hav e been recovered from sponge-algal mounds at the base of this unit (sample CAS 3). The se conodonts represent Midcontinent warm-water species, typical of coeval shallow-water deposits in the Precordillera. Grainstones and packstones with cherts, bioclasts, and intraclast s are associated with those mounds.

50

OLlVER LEHNERT, MARTIN KELLER and OSVALDO BORDONARO

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Other species ob tained from unit 3 such as P. gra ci lis, Sco lopodus cf. rex, D. arcuatus, and T. sweeti are already prese nt in older beds at Cerro La Si lla. The biostromal hor izo ns at the top of unit 3 formed during the O. evae chron, as ind icate d by the presence of the zonal index fossil. In these horizon s, the abundance of the large receptac ulitid Fischerites cama cho is interesting . In the Precordillera, this receptac ulitid is presen t in the upp er O. evae Zone in the Niq uivil section (approx . 10 km SSW' of Cerro La Si lla) .

EARLY O RDOV ICIAN CO NODONTS FRO M SOUTHERN CUYA NIA TE RRANE

53

Th e age determinati on for the top of the Pon on Trehue Form at ion (unit 4) is hamper ed by the lack of zona l ind ex fossil s. Th erefore, the San Rafael faunas hav e to be ind irectly co rre lated mainl y by co mpariso n with coeval stra ta in the Precordill era, from where the index foss ils have previou sly been descr ibed . Th e presen ce of P. origina lis indi cates that th is fa una is not older than the P. orig ina lis Zo ne . In the Precordillera, however, the associatio n of P. cryptodens, P. originalis, and D. basiovalis is only present in the Amorphog nathus variabilis Zon e and the ove rly ing E. su ecicus Zo ne (LEHN ERT 1995 ; ORTEGA et al. 1995 ). In the E. sueeieus Zo ne , thi s assemblage is associated with H. kristi nae and E. su ecicus. Becau se P. fla bellum, whic h is present at the top of the Ponon Trehue Forma tio n, is replaced by Periodon aculeatus within the A . variabilis Zo ne, the top of the successio n ca nnot be yo unger than the lower part of the A. variabi lis Zo ne . Ano ther line of evi de nce altho ug h suggests a corre lation w ith the lo wer A. variabilis Zo ne. P. cryptodens is a typi cal species of the fo llow ing un its: ( I) Histiodella altifro ns Zo ne; (2) the M. fla be llum/T. laevis and P. cryptodenslliist iode lla altifro nslMultioistodus auri tus inte rva l of ETIIINGTON and CLARK 1982 ; and (3) Midcon tin ent faunas I and 2 (SWEET et al. 1971 ). A ll these units are co rre lated with the lower A. variabi lis Zo ne. In co ncl usio n, the faunas in the upperm ost hori zon s of un it 4 d iscu ssed so far re prese nt eleme nts which are typi cal of the upp er Sa n Ju an Fo rma tio n. In the Precordillera, these fau na s are attribute d to the Late Arenig (LEIINERT 1995). By co mparison with the stra ta in the Precord illera , we attr ibute the sedi me nts at the top of the Pon on Trehue Fo rma tio n also to the Late Are nig . Critical to thi s ass ignme nt is the presen ce of Oistodus'l tablepointensis. T his spec ies has been re ported so far only from Late Wh iterockian/E arl y Llan virni an strata in Newfoundland (STOUGE 1984 ), where it has o nly a short range from the lower Hist iodella tab leheadensis ph ylozon e (= Histi odell a holodentatai to the lower part of the Histiodella kristinae ph ylo zon e of STOUGE (1984: fig . 18). Th is inter val corre lates w ith the upp er A. variabilis to lower E. suecicus Zo ne in the Baltoscand ic area (Fig. 3). Th e prese nce of Ois todus'l tab lepointe nsis indi cates ei ther that the strata at the very top of the Pon on T reh ue are yo unge r than we ass ume fro m the accompa nying fa unas or that the taxon appea red s lightly ea rlier in the Cuyania Terrane than in Newfoundland . An assig nme nt to the Late Are nig is also co rrobora ted by the pre se nce of Protopanderodu s gra dat us and Pa roistodus origina lis which are rep laced by the ir successo rs duri ng the A. variabilis Zo ne . DI SC US SI O N Biost rati graphi c correlations of the Upper Trem ad oc to Upper Aren ig stra ta near Sa n Rafael w ith coeva l miogeoclinal stra ta in the Precordillera (Cerro La Si lla section) permit a co m par iso n of fa una l co m pos itions and sedi mentology bet ween bot h successions . In both successions, there is a tren d in co mpositio n of co nodo nt faunas of the war m-water gro up in the lower part to pandemic and temperate-water faunas in the yo unger strata. In the Ponon Tre hue Formation. this tre nd is refl ected in the sediments of un it I to basa l un it 3. In the Precordillera, this trend is present from the up per part of the La Silla For mation to the lower par t of the Sa n Ju an Form ation . Add itionally, in both areas represent atives of the co ld-water gro up co me in wit h the globa l transgression of O. evae Zo ne (uppe r unit 3 of the Pon on Trehu e Forma tion) . Th is eustatic eve nt represents the most ex tensive sea -leve l rise during Early Ordov icia n times (e.g., BAGNOLl 1994 ). Th e lower biostro ma l succession (base of unit 3) correspo nds to the lower reef mou nd horizon at Cerro La Si lla as described by CANAS and CARRERA ( 1993) . The upp er biostrom al co mplex (to p of un it 3) tent atively is co mpared w ith the upper reef mound horizon in the Sa n Juan Formatio n. Both form ed during an initia l rel ative sea-level rise. Th e pronoun ced sea-leve l rise (nodular limestones of unit 4) in the upper part of the Pon on Trehu e For mation is reflected by the common occ urre nce of ope n-mar ine eleme nts such as Periodon fl abellum . Th e same eve nt is also observed in the sec tio ns of the Precordill era (KELLER 1997 ). Thi s deepening du ring the Late A renig finally led to the dro wnin g of the Precordilleran car bonate platfo rm during Ear ly Llan vim times . Wh en co m pared wi th the sec tio ns of the ca rbo nate platfo rm in the Precordillera (BORDONARO et al. 1996 ), the carbo nate s ex po sed in the Sa n Rafael area represent a strong ly reduce d successio n. Abo ut 80 m of carbo nates near San Rafael correspond to mo re than 300 m of lim eston es in the miogeocl inal success ion (F ig . 4). Furthermo re , mor e than 1500 m of Ca mbrian and Ea rly Ordovic ian se dime nts were dep osit ed on this carbo nate platform (La Laja Forma tio n, Zo nda Fo rma tio n, La Flech a Forma tio n, and the lower part of the La Sill a Forma tio n) unt il the first carbo nates onlapped the basem ent in the Pon on Trehu e area (F ig. 4) . Stro ng ly redu ced sed iment thick nesses, togeth er with the Ordo vici an onlap onto the basem ent , ind icate tha t the outcrops at Pon on Trehu e rep rese nt a cra to na l setting, the only cra to na l sec tio n known fro m the Cu yan ia terrane so far.

54

OLlV ER LEII ERT. MARTI N KELLER and OSVALDO BORDONARO

Precordillera

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Ord ovician co nodo nt paleobiogeograph y and provincialism have been discussed and docum ented in various papers. Aspects of the Early Ordo vician have been stresse d by ETlII NGTON and REI'ETSK I ( 1984), MII.I.ER ( 1984), BERGSTROr-.l ( 1990), and BAGNOI.I and STO UGE ( 199 1, 1996). The co nodont s from unit I to basal unit 3 as well as the fauna s from the La Silla Formation and the lower San Juan Formation (LEH ERT 1997) are typical of the North American Midcontin ent Faunal Pro vince. The presence of these conodo nts toge ther with almost identic al, coe val reef structures from the San Juan Formati on (CA-AS and CARR ERA 1993; CA- AS and KEI.LER 1993) agrees with the interpretati on that the San Rafael region is a part of the Cuyania Terrane. Fauna l composition and sedimento logy of the Ponon Trehu e Form ation are in agreemen t with a derivation of the terran e from the so uthern margin of Laurentia (e.g.. DALLA SALDA et al. 1992a, b; DALZIE L et al. 1994; ASTINI et al. 1995; DALZI EL 1997; KELL ER 1997).

TAX ON OM IC AN D BIO STRATI GR APHI C REM ARK S

The conodont s from San Rafael show a high thermal maturation. The conodont elem ent s exhibit a high Color Alteration Index (CAI of EI'STEI N et al. 1977) of about 6. Accordin g to REJEBI A et al. ( 1987), this suggests a thermal heatin g between 360 and 550°C. Unfortun ately, the co nodonts are partly recrystalli zed and fragm ented, but the faunal elements can be well compared with those described from the Argentin e Precord illera (La Silla Formati on and San Juan Form ation ).

EARLY ORDOVICIAN CONODONTS FROM SOUTHERN CUYA N IA T ERRAN E

55

The species mention ed in the text are well known from many other areas including the Precordillera proper. Therefore, they are listed only with reference to their original descriptions and to descriptions in the scope of multielement taxonomy or detailed synon ymy lists. The occurrences in the Precordillera are not specifically discu ssed in this paper, but are added only for stratigraphic information. Unles s otherwise stated, we always refer to the standard Cerro La Silla section, the type section for both the La Silla Formation and the San Juan Form ation as defined by KELLER et al. (1994 ). Bergstroemognathus extensus (GRAvES et ELLlSON, 1941) . - Oistodus ex tens us sp. n. - GRAVES and ELLlSON 1941: p. 13, pI. I: 16, 28 (M element); Bergstroem ognathus ex tens us (GRAVES et ELLISON, 1941) - SERPAGLI 1974: pp. 40- 43, pI. 9: l a- Se; pI. 21: 1-7 ; text-fi g. 7 (synonymy of multielement species until 1974), STOUGE and BAGNOLl 1988: p. 113, pI. I: 6-13 (synonymy until 1988), LEH NERT 1995: p. 75, pI. 5: 20, 21 ; pI. 20A : 6; pI. 20B: 2 (synonymy until 1994). The species is present in samples CAS 5 to CAS 7 (unit 3). In the Precordillera, it is common in the lower part of the San Juan Formation where it first appears in the P. elegans/O. co mmunis assemblage zone. Colaptoconus quadraplicatus (BRANSON et MEIIL, 1933). - Scolopodus quadraplicatus sp. n. BRANSON and MEHL 1933: p. 63, pI. 4: 14, IS; Glyptoconus quadraplicatus (BRANSON et MEHL) KENNEDY 1980: pp. 61-63, pI. I: 39-45 (detailed description and synonymy), STOUGE and BAGNOLl 1988: p. 120, pI. 3: 20, 21 (synonymy until 1988); LEHNERT 1995: pp. 89-90, pI. I : 10, 12, pI. 2: 15-16, 18 (synonymy until 1994). The species was found in sample CAS 3 (reef mound s, basal unit 3). In the Precordillera, it is observed from the upper La Silla Formation to the P. eleg ans/O. co mmunis assembl age zone of the San Juan Formation. Drepanodus arcuatus PANDER, 1856. - LOFGREN 1978: pp. 51-5 3, pI. 2: I, 2, 4-8, non 3 (D. planus] (description and synonymy until 1978), STOUGE and BAGNOLI 1988: pp. 115-116, pI. 2: 1-6 (detailed synonymy until 1988), STOUGE and BAGNOLI 1990: p. 14, pI. 9: 7-10 (synonymy until 1990 ), LEHNERT 1995: p. 82, pI. 3: IS, 16 (synonymy until 1994). The species is present in sample CAS 5 (unit 3). In the Precordill era, it is common in the San Juan Formation first occurrin g in the A. ?de ltatus/P. p roteus asse mblage zone. "Drepanodus" gracilis (BRANSON et MEIIL, 1933) sensu LINDSTROl\I, 1955 s.f. - Drepanodus'l grac ilis BRANSON et MEIIL - L1 NDSTROM 1955: pp. 562-563, pI. 4: 44 , pI. 5: 6, 7; Drepanodus g racilis (BRANSON and MEHL 1933) sensu L1 NDSTROM 1955 - ETHI NGTON and CLARK 1982: pp. 37-38, pI. 3: 7,

text-fi g. 10 (description and synonymy until 1981). Drepanoistodus basiovalis (SER(;ISTROl\I, 1955) . - Oistodus fo rceps sp. n. - L1 NDSTROM : p. 574, pI. 4: 9- 13, text-fi g. 3M; Drepan oistodu sforcep s (LI DSTROl\I) - LOFGREN 1978: pp. 53-55 , pI. I: 1-6; text-fig. 26A (detailed descripti on and synonymy until 1978), STO UGE and BAGNOLl 1990 : p. 16-17 , pI. 5: 6-9 (synonymy until 1990 ), LEII NERT 1995: p. 86, pI. 3: 20; pI. 6: 2 (synonymy until 1994 ). The species was obtained from samples CAS 9 and CAS 10 (unit 4). In the Precordill era, it is present from the O. el'lle Zone up to the top of the San Juan Formation (A. var iabilis Zone). Erraticodon 'l balticus DZIK, 1978. - Tli rraticodon balticus sp. n. - DZIK 1978: p. 66, pI. IS: 1-3 ,5 , 6: text-fig. 6 (description); ?Erraticodoll balticus DZI K- LEH NERT 1995: pp. 87- 88, pI. 9: 13. 16 (synonymy until 1994). The Erra tico do n elements present in samples CAS 9 and CAS 10 (unit 4) most probably correspond to Erraticodon balticus. However, the preservation of the fragmented material does not permit an unequivocal determination. One M element of an Erraticodon with a long proce ss is not typical of this specie s (DZIK personal communication). This element is figured as Erraticodon sp. (PI. 2: 14). E. balticus is found in the uppermost part of the San Juan Formation (SARMI ENTO 1990).

56

OLl VER LEHN ERT, MARTIN KELLER

and

OSVALDO BORDONARO

Eucharodus parallelus (BRANSON et MEHL, 1933). - Drepanodus parall elus sp. n. - BRANSON and MEH L 1933: p. 59, pI. 4: 17; Eucha rodus pa rallelus (BRANSO N et MEHL) - KENNEDY 1980: pp. 58-60, pI. 1: 35-38 (detailed descripti on and synonymy until 1980), STO UGE and BAGNOLl 1988: p. 11 8, pI. 3: 14 (synonymy until 1988), SMITH 1991 : pp. 33-34, text-fig. 19d- f (detailed synonymy until 1991), LEH NERT 1995 : p. 88, pI. 2: 15, 16, 18 (synonymy until 1995). The species was obtained from sam ple CAS 3 (unit 3). It is also present in the lowermost part of the San Juan Formation (G. quadraplicatusl R striatus to basal P. elega ns/O . communis assemblage zone). Fahraeosodus marathonensis (BRA DSHAW, 1969). - Gothodus marathonensis sp. n. - BRADSHAW 1969: p. 1151 , pI. 137: 13-15 , text-fig. 3S-U; "Mikrozarkodina " marathonensis (BRADSHAW) - ETHINGTON and CLAR K 1982: pp. 55-56, Taf. 5: 14, 19, 20, 23, 24, 27 (detailed description of multielement species and synonymy until 1981); Fahraeosodu s marathonensis (BRADS HAW) - STOUGE and BAGNOLl : p. 119, pI. 4: 15-17 (synonymy until 1988), LEH NERT 1995: p. 89, pI. 7: 19, pI. 8: I (synonymy until 1994). The species is present in sample CAS 7. It represents a rare eleme nt of the San Juan faunas (0. evae zone to Assemblage VI in the upper part of the Niqui vil section; LEH NERT 1993). Iuanognathus jaanussoni SERI'AGLI, 1974. - Juan ognathus jaanussoni sp. n. - SERPAGLI 1974: pp. 50,51 , pI. 11 : 8a-1 2c; pI. 23: la -5b; text-fig. 9 (detailed descripti on and synonymy until 1974 ), LEH NERT 1995 : p. 92, pI. 3: 2, 3 (synonymy until 1994). The species is found in sample CAS 5 (unit 3). It is co mmon in the middl e and upper part of the San Juan Formation. Oepikodus communis (ETIIINGTON et CLARK, 1964). - Gothodus communis sp. n. - ETHI NGTON and CLARK 1964: pp. 690, 692, pI. 11 4: 6, 14 ; text-fig. 2F; Oepikodus commu nis (ETHINGTON and CLARK) STOUGE and BAGNOLl 1988: p. 121, pI. 5: 8- 12 (synonymy until 1988), LEH NERT 1995 : pp. 98-99, pI. 5: 22, 27- 29; pI. 8: 19- 24 (syno nymy until 1995). The species was obtained from sam ple CAS 5 (unit 3). In the San Juan Formation, it is present from the upper P. elegans/O. communis to the O. evae Zo ne. Oepikodus evae ( L1 'DSTRC)I\I, 1955). - Prioniodu s evae sp. n. - LINDSTROM 1955: p. 589, pI. 6: 4-10; Prioni odus (Oepikodus) evae L1 N D S T R O ~I- SERPAGLI 1974: pp. 67-69, pI. 15: 9a- 13; pI. 26: 1-10; pI. 3 1: I (descriptio n and synonymy until 1974), LOFGREN 1978 : pp. 79, 80, pI. 9: 7-1 1, 17A, B (synonymy until 197 8); Oepi kodus evae (L1 NDSTRC)M) - STO UGE and BAGNOLl 1988: pp. 121, 122, pI. 5: 1- 7 (synonymy until 1988), LEH NERT 1995: pp. 99- 100, pI. 20B : 1 (synonymy until 1994). The pandemic species was obtained fro m sample CAS 7 (top of unit 3). It is abundant in the O. evae Zone in the Precordill era (references co mpiled by SARM IENTO and GARCI A-Lo PEZ 1993). Oistodus aff.lanceolatus PANDER, 1856. - TOistodus ei i.lanceolatu s PANDER- STOUGEand BAGNOLl 1988: p. 123, pI. 6: 1-8 ; LEH NERT 1995: p. 101. pI. 8: 6-8; pI. 20B: 12 (description and synonymy). The species was found in samples CAS 9 and CAS 10 (unit 4) and is mainl y assoc iated with other shallow-water species in the reef mound hori zons of the upper San Juan Form ation (asse mblages V and VI of LEHNERT 1993). Oistodus't tablepointensis STO UG E, 1984. - Oistodus'l tabl epointensis sp. n. - STOUGE 1984: pp. 75-76, pI. 14: 2- 12 (descr iption and synonymy). Para cordylodus gracilis LINDSTROl\I, 1955. - Paraco rdylodu s gra cilis sp. n. - L1 NDSTR OM 1955 : p. 584, pI. 6: 11-1 2 (S ele ment); LOI'GREN 1978: pp. 67-68, pI. 9: 15A-1 6B (synonymy of the multielement species until 1978); LEH NERT 1995: p. 105, pI. 4: 3 (synonymy until 1994). The species was found in sample CAS 6 (unit 3). P. gra cilis is always represe nted by a few individuals only. However, this species is widely distributed on the San Ju an platform. Thi s distr ibution was discussed by SARM IENTO and GARCI A-Lo PEZ ( 1993). P. gra cilis is observed in the P. elegans/O. communis assemblage zone at Cerro La Silla and in the P. elega ns and O. evae asse mblage zones in Niquivil (LEHNERT 1993). Paroistodus originalis (SERGEEYA, 1963). - Oistodu s originalis - SERGEEVA 1963: p. 98, pI. 7: 8, 9; text-fig. 4; Paro istodu s originalis (SERGEEYA) - LbFGREN 1978: pp. 69-71 , pI. I : 22-25; text-fig . 28 (desc ription and syno nymy until 1978), STOUGE and BAGNOLl 1990 : p. 22, pI. 7: 5-10 (synonymy until 1990), LEH NERT 1995: pp. 109, 110, pI. 7: 2, 3; pI. 13: 5 (synonymy until 1994).

EARLY ORDOVICIAN CONODONTS FROM SOUTHERN CUYANIA TERRANE

57

Periodon flabellum (LINDSTROM, 1955). - Periodon flab ellum (LINDSTROM) - LOFGR EN 1978: pp. 72-74, pI. 11: 1-11 , text-fig. 29 (pars) (description and discussion, synonymy until 1978), LEH NERT 1995: p. 112, pI. 7: 8,10,11 (synon ymy until 1994). The species is present in samples CAS 8 to CAS 10 (unit 4). P. flab ellum is common in the San Juan Formation, ranging from the O. evae Zone to the top of the San Juan Formation (approx . M . parva Zone - first transitional form s into P. aculeatus zgierzensis DZIK, typical elements of P. aculeatu s HADDING are found at the top of the San Juan Formation). Protopanderodus gradatus SERI'AGLI, 1974. - Protopanderodus gradatus sp. n. - SERPAGLI 1974: pp. 75-77, pI. 15: 5a-8b ; pI. 26: 11-15 ; pI. 30: l a, b; text-fig. 17 (description and synonymy until 1974), LEH NERT: p. 117, pI. 3: 11 , 12 (synonymy until 1994). The species was obtained from samples CAS 8 to CAS 10 (unit 4). It ranges from the lower part of the San Juan Formation (P. eleg ans 10. communis assemblage zone ) to the A . variabilis Zone (top of the formation at Cerro Potrerillo, north of the Rio Jachal, ORTEGA et al. 1995). Pteracontiodus cryptodens MOUND, 1965. - Pteracontiodus cryptodens sp. n. - MOUND 1965: pp. 197-198, text-fi gs 1-2, 12, 13, ETHI NGTON and CLARK 1981: pp. 88-89, pI. 14: 1-4,6-10 (synonymy of multiel ement species to 1981), LEHNERT: pp. 119-120, pI. 7: 7; pI. 13: 13. The species is present in samples CAS 9 and CAS 10 (unit 4) . It is a typical species of the M . parva and A. variabilis zones in the Precordillera (ORTEGA et al. 1995). Reutterodus andinus SERPAGLI, 1974. - Reutterodus andinus sp. n. - SERPAGU 1974: pp. 79-81, pI. 17: 9a-d; pI. 28: 1-9b ; text-figs 19-20 (detailed description of multielement species); Reutterodus andinus SERPAGLI - LEHNERT 1995: p. 122, pI. 7: 9-13 (synonymy until 1994). The species was obtained from sample CAS 5 (unit 3). In the Precordillera, the species is first observed in the P. eleg ansl O. communis assemblage zone. It is an important representative of the O. evae Zone . Scolopodus cf. rex LINDSTROM, 1955. - cf. Scolopodu s rex sp. n. - LINDSTROM 1955: p. 595, pI. 3: 32; cf.1978; cf. Sco lopodus rex LINDSTROM - LbFGREN: p. 109, pI. I : 38-39 (detailed synonymy until 1978); Scolopodus cf. rex L1 NDSTROM - LEH NERT: pp. 124-125 , pI. 5: 5-6. The species is present in samples CAS 5 and CAS 6 (unit 3). In the Precordillera, it is first observed in the A. ? deltatus IP. proteus assembl age zone and ranges up into the upper O. evae Zone . Scolopodus? krummi (LEHNERT, 1995). - Tropodu s'l krummi sp. n. - LEH NERT 1995: pp. 130-131 , pI. 5: 18, 19 (detailed description). The species is present in samples CAS 6 and CAS 7 (unit 3) and in the lower part of the San Juan Formation which corre sponds to the O. communis/P. eleg ans assemblage zone . Spinodus sp . - broken fragments of Spinodus have been found in sample CAS 10 (top of unit 4) . In the Precordiller a, the olde st Spinodus elements [Spinodus spinatus (HADDI NG, 1913)], have been found in the upper part of the San Juan Form ation correlated with the M. parva and A. variabilis zones (e.g., SARMI ENTO 1990; ORTEGA et al. 1995). Striatodontus prolificus (JI et BARNES, 1994). - Striatodontus prolificu s - JI and BAR NES 1994: pp. 61-62, pI. 20: 1-26 ; text-fig. 36A (detailed description and synonymy). Element s of S. prolificus from the uppermost La Silla Formation and lowermost San Juan Formation have been identified by LEH NERT (1995 : pI. I : 15) and LEH NERT et al. (in press: pI. 2: 22, 23) as Parapanderodus striatus (GRAVES et ELLlSON, 1941). However, as discussed by LEII NERT ( 1995: p. 107), the element s from the Precordillera are more robu st and shorter than typical elements of P. striatus. In addition , they show a high content of white matter in the cusp instead of being hyaline . Similar elements have been assigned to P. striatus by ETHI NGTON and CLARK (1982), REPETSKI ( 1982), and Ro ss et al. (1993 ) and therefore it should be noticed that in published charts the range of this species includes that of S. prolificus. The species was found in samples CAS I and CAS 3 (unit I and basal unit 3). In the Precordillera, S. prolificus is present in the upper part of the La Sill a Form ation and in the basal San Juan Formation . Tropodus sweeti (SERPAGLI, 1974). - "Paltodus" Tsweeti sp. n. - SERPAGLI 1974: pp. 58-59, pI. 14: 13a-14b; pI. 24: 8-10; text-fig. 12 (P element); Tropodus swe eti (SERPAGU) - STOUGE and BAGNOLl 1988: p. 142, pI. 16: 10-15 (synonymy of multielement species), LEHNERT 1995: pp. 131-132 , pI. 3: 17-19 (synonymy until 1994).

58

OLl VER LEH NERT. MARTI N KELL ER and OSVALDO BORDO NAR O

The spec ies was found in sam ple CAS 5 (unit 3) . In the San Ju an Formation, T. sweeti is fir st ob served in the A. ? deltatu s/P. proteus assembl age zo ne (Ce rro La Silla sectio n) and rang es up into Assemblage IV (Niquivil section, LEHNERT 1993 ).

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of America, Memoirl27 , 83- 161. BERGSTR()M, S .M . 1990 . Rel at ion s bet ween co nodont pro vincialism and the cha ng ing palae ogeogr aph y during the Early Pal eo zoi c. In: W .S . McK erro w and e. R . Scotese (e ds) , Pal aeozo ic Pala eogeogr aph y an d Biogeo graphy . - Geolog ica l Soc iety of Lond on , M em oir 12 , 105 -1 21. BORDONARO, 0. , KELL ER, M. , a nd LEIINERT, O . 1996. El Ordo vfcic o de Pon on T rehue e n la Pro vin cia de Mendo za (Argentina ): rede fi nicio nes estratigraficas. - 13. Congreso Geo logico A rgen tina y 3. Con greso de Exp loracio n de Hidrocarb uros Aetas I, 54 1-550 . Bue nos A ires . BRADSHAw , L. E . 1969 . Cono donts from th e Fort Pefia Forma tio n (M idd le O rdo vici an) , M aratho n Basin , T e xas. - Jou rnal of Pal eont ologv 43 . 1137-11 68 . BRM, SON, E. B. a nd M EH L, M .G . 19 33. Co nodo nt stud ies . - The Univ ersity of Missou ri, Studies 8 , 1- 34 9 . CANAS, F. a nd CARRER A, M. 199 3. Ea rly Or dov ic ian mi c robi al-sp on ge- receptacul iti d bi oh erm s o f the Preco rdill era, westem Arge ntina . - Faci es 29 . 169-178. C ANAS, F. and KELLER, M. 199 3. Arrecifes y mont fcul os arreci fa les e n la For mac i6 n San Ju an ( Precordi llera Sa nj ua nina . A rge ntina): Los arrec ifes rnas antig uo s de Sudamerica . - Bolet fn de la Real Soc iedad Espa iiol de Histori a Natura l, Seccion Geolog ica 88 , 127 -1 36 . CRIADO ROQLl E, P. and IBANEZ, G . 1979. Pro vin c ia Geo logica Sa nra fae lino- Pa m peana . In: A .F . Leanza (ed .), 2 . Simposio de Geologia Regional Arg entina I, 837 -869 . Academ ia Nac io na l de C ienc ias, Cordoba. Arge nt ina . D AI.I.A SALDA, L.H oo Ci NGOLANI, Coo a nd VAREI.A, R. 199 2a . Ea rly Pal eo zoi c oroge n ic belt of the A ndes in so uthweste m So uth A me ric a : Result o f Laurent ia -Gon d wan a co llision? - Geo logy 20 , 6 17-620 . DAI.I.A SAI.D A, L.H oo DALZIEL. l.W .D .. Ci NG OLANI, e.A .. and VAREI.A, R . 199 2b . Did th e T acon ic A ppa lac h ia ns co ntin ue into so uthe m So uth America ? - Geo logy 20 . 105 9-1 0 62. D AI.ZIEL, I.W.D. 1997 . Ne oprot e ro zoi c- Ea rly Paleo zoic geography an d tec ton ics : Re vie w, hy pothesis, env iron me nta l spec ulati on - Geo log ica l Soc iety of Am eri ca, Bull et in 109 . 16-42. DAI.ZIEI., l. W .D ., DALI .A SALlJA, L.H .. and G AII AGAN. L. M. 1994 . Pa leozoic Lau renti a-Gond wan a in te rac tio n a nd the origi n of th e A ppa lac h ia n-Andea n mountai n sys te m . - Geo log ica l Soc iety of Am eri ca , Bull etin 106 , 243-252 . DZIK. J. 19 78. Cono do nt biost rat igraph y and pa leogeographical rel ati on s o f th e Or dov ician Mojcza Lim est on e (Ho ly Cross M ts.. Pol an d ). - Acta Palaeontologica Poloni ca 23 . 5 1-72. EpSTEIN, A .G oo EpSTEIN. J .B.. a nd HARRls , L.D. 1977. Conodon t co lor alterat ion - an index to org an ic me ta morp hism . United State s Geolog ical Survey, Professiona l Paper 995 , 1- 27. ETIIINGTON. R.L. a nd CLARK , D .L. 1971. Lo we r O rdov ician con odonts in North A merica . In: W .e. Swee t a nd S .M. Bergstr om (eds) , Sym po siu m o n Co no dont Bio strati gr a ph y. - Geo logi cal Society of America, M em oir 127, 63 -82 . ETIIINGTO N. R .L. a nd C LARK. D.L. 19 82 (imp rint 1981). Lo wer and Middl e O rdov icia n co no do nts fro m th e Ibe x Area, W estem Mill ard County . Utah . - Brigh am Youn g University Geology, Studies 28 , 1-1 55 . ETIIINGTO N. R. L. and REPETSKI. J. E. 19 84 . Paleob io geo gr aphi c di st ributio n of Ea rly Ordov ic ian co nodonts in cen tra l and wes tern United Sta tes . In : D.L. C lark (ed .), Co nodont Biofacies and Pro vinciali sm . - Geological So cie ty of Ame rica , Special Paper 196, 89 - 10 I. FINNEY, S .e. a nd ETIIIN GTON, R. L. 1992 . Wh ite rockian grapto lites and co no do nts fro m th e Vinini Fo rma tio n, Nevada: Bio st rati gr aphi c im pli cati o ns. In: B.D. W eb by a nd J .R . Laurie (eds ), Glob al Persp ecti ves on Ord ovician Geo logy . 153-1 69. Rott erdam (Balke ma) . GRAVES. R .W . a nd ELI.ISON. S. 1941. O rdovic ia n co no do nts of the Mar ath on Basi n. T e xas. - Unive rsity ofMissou ri, Schoo l of Min es and Metallurgy, Bull etin 14, 1- 26. HARRls, A .G. , D UMOLlLl N, J.A ., REPETSKI , J .E. , a nd C ARTER , e. 1995. Co rre la tion o f Ordov icia n rocks of no rthe rn Alas ka . In : J. Coo per. M .L. Dro ser. and S .e. Finney (eds) , O rdov icia n O dyssee . - Pacifi c Section SE PM 77 . 2 1-26.

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HEREDIA, S .E. 1982. Pygodus an serinu s Lam ont & Lindstr orn (Conodonto) e n e l Llandeilian o de la Form aci 6n Pon on T rehu e, Pro vin ci a de Mendoza, Argen tina . - A meghiniana 19, 229-233 . JI, ZAILlANG and BARNES, e. R. 1994 . Low er Ord o vici an co no do nts of the SI. George G roup, Port a u Port Peninsul a, weste rn New fo und land, Ca nada . - Pal aeon togr ap hica Canadiana 11, 149 . KELL ER, M. 1997 . Th e Arge nti ne Precordillera - se d ime nto logy and plate-tectoni c hist or y of a Laurenti an c rusta l frag me nt in So uth Ame rica . Unp ub lished Habilitation thesis, Geo logisches ln stitut Erlangen, 1- 239 . Erl an gen . KELLER, M. , CANAS , F., LEIINERT, 0 ., and VACCA RI, N.E. 1994 . Th e Upper Ca mbrian and Low er O rdov ic ia n of th e Precordill e ra (wes tern Argentina) : So me stratigraphic recon sid erati on s. - News letters on St ratigraph v 3 L I 15-1 32. KELLER, M. and DICK ERSON, P.W . 1996. Th e mi ssin g co ntin e nt of Llan oria - was it the Arge ntine Precodillera? - 13. Co ngre so Geo log ico A rge ntina y 3. Cong reso de Exp loracion de Hid rocarbu ros Actas 5, 541 -5 50 . Bu en os Ai res . LEH NERT, O . 1993. Bioestratigr afia de los co no do ntes Are nig ianos de la Formac i6n Sa n Ju an en la locali dad de Niquivil (Precordi llera Sa njua nina , Argentina) y su corre lac i6n interco ntinenta l. - Revi sta Espa iiola de Pal eontologia 8 , 153-

164. LEH NERT, O . 1995. Ordov izisc he Co no do nten aus der Prak ord ille re Westar gentinien s: Ihre Bedeutung fu r Stratigrap hie und Palaogeogr aph ie . - Erlange r Geo logische Abhand lunge n 125,1 -1 9 3. L EIINERT, 0 ., MILLER, J.F., an d REPETSKI , J .E. 199 7. Paleogeographi c sig nifica nce of Cla vohamulus hintzei Miller (Conodo nta) and other Ibe xia n co no do nts in an ea rly Pale o zo ic carbona te platfor m faci es of th e Argent ine Preco rdill e ra. Geo logical Soc iety of America , Bull etin 109, 429--44 3. LEVY, R. an d NULLO, F. 19 75 . Braqui 6p od os ordov fcicos de Pon on -T rehue, Bl oqu e de Sa n Rafael (Prov incia de Mend oza ) Arge ntina . - I . Congreso A rge ntine de Paleont ologia y Bioestratigrafia Aet as L 23-32 ; San Mi guel de Tu cuman , A rgen tina . LINDSTRClM, M . 1955. Co no do nts fro m th e low ermost Ord o vici an strata of So uth-Ce ntra l Sw ede n. - Geo logiska Fore ningens i Stockho lm Forha ndlinga r 76 , 5 17-604 . LINDSTRClM, M. 1971. Low er Ordo vician co no do nts of Europe . In : W .C . Swee t and S .M . Bergstrorn (eds) , Sy mpos ium on Co nodo nt B iostratigraphy. - Geo logical Society of A me rica, Me mo ir 127 , 2 1-6 1. U WGREN, A . 1978. Arenigian and Llan virni an co nodonts fro m Jamtl and, nor thern Sweden. - Fossils and St rata 13, 1-129 . LOFGREN, A . 1993. Co nodonts from th e Lo wer O rdo vic ian at Hun neb erg, so uth-cen tra l Swede n. - Geo logica l Ma ga zine 130, 2 15-232 . MILLER, J. F. 1984. Cam brian and ea rliest Ordov ician conodo nt evo lutio n. biofacies . and pro vinc iali sm . In: D.L. C lark (ed .), Co nodon t Biofaci es an d Pro vinci ali sm . - Geo log ical Soc iety of A mer ica, Special Pap er 196, 43-68. NUJ':Ez, E. 196 2. So bre la presen cia de Paleo zoi co Infe rior en el Bloqu e de Sa n Rafael. - Prim era s Jomad as Geo logicas A rge nti nas Aetas 2, 185-1 89. NUNEz, E. 19 79. Desc ripc i6n geo log ica de la hoj a 28 d , Estac ion So itue . Provin cia de Mendo za . - Servicio Geo log ico Naciona l Boletin 166, 1- 67. PADULA, E. 1951. Co ntri buc i6n al co noc imie nto geo l6gico del amb ient e de la Cord illera Fro nta l, Sierra Pint ad a, Sa n Rafael , Mendo za. - Revista de la Asociacion Geo logica Argen tina 6, 5- 13. RAM OS, V.A. 1995. Suda rnerica: un mosaico de co ntinen tes y oceanos. - Ciencias IIOY 6, 24-29. RAM OS, V.A. 1988, Late Prot ero zoi c- Early Pal eozoi c of So uth Americ a - a co llisio na l hi stor y. - Ep isodes 11, 168-1 74. RAMOS, V.A., JORDAN, T.E., ALLM END ING ER , R.W .. MI'ODOZIS, C; KAY, S .M . COR'n !s, J.M.. and PALMA, M. 1986 . Paleozo ic terr anes of the ce ntra l Argenti ne-C hilea n Andes . - Tectoni cs 5, 855-880. REJEBI AN, V.A .. HARRI S, A.G. , and HUEBNER, J .S . 1987. Co nodont co lor and te xtur al alteration: A n index to regional metam orphi sm , co ntac t metamorph ism a nd hyd roth e rmal alteration. - Geological Society of A me rica, Bull etin 99 , 471--479 . REPETSKI , J. E. 1982. Co nodo nts from El Paso Group (Lowe r Or dovician) of western most Te xas and so uthe rn New Mexico . - New Mex ico Bu reau of Min es an d M ineral Resources, Me moir 40 , 1-1 21 . Ro ss , R.J. , Jr., HINTZE, L.F.. ETHINGTO N, R.L. , MILLER, J.F., T AYLOR, M. E., and REPETSKI, J .E . 1993. Th e Ibexian Seri es (Lower O rdovician), a replace me nt for "Canadi an Series " in No rth A mer ica n c hronostra tigraphy. - United Sta tes Geo log ica l Survey, Ope n-File Repo rt 93-598, 1- 75. SARM IENTO, G . 1990 . Cono do ntes ordovfc icos de Arge ntina . - Treb alls del Mu seu de Geo logia de Bar celona 1. 135-1 61 . SARMI ENTO, G . and GARCfA LOPEz , S . 1993 . Sfntes is sobre las faun as de co nodon tos de l Paleozo ico Inferior de lbero- Am erica y de la Penfn sul a ibe rica (19 58 - 1992). - Revista Espaiiola de Pa leontolog ia 8 , 191 - 205 . SERPAGLl, E. 19 74 . Lo wer Ordovic ian co nodo nts from Precordilleran Argen tina . - Boll ettino della Societa Pal eontologica Itali an a 13, 17- 98. STOUGE , S . 1984 . Co nodo nts of th e Midd le O rdov icia n T able He ad Forma tion, western New fo und land - Foss ils and Strata 16 , 1- 145 . STOUGE, S . a nd BAGNOLl, G . 1988. Ea rly O rdov ician co no do nts from Cow Head Peninsul a; Western Ne wfo un d land . Pal aeontographia ltali ca 75 , 89 -179 . STOUG E, S . a nd BAC, NOLl, G . 1990. Lo wer O rdov ician (Vo lkhovian- Kunda n) co nodo nts from Hagudden , nor thern b land, Swed en . - Pala eont ograph ia ltalica 77, I- 54. SWEET, W .e. 1984. Graphic correlatio n of upper Middl e and Upper O rdov icia n roc ks, Northern A me rican Mid cont inent Pro vin ce, U.S.A . In : D .L. Brut on (ed .), Aspects of the Or do vician Sy stem . - Paleont ological Con tr ibut ions of the Univers ity of Oslo 295, 23-35 . SWEET, W .e. , ETIIINGTON, R.L. , and BARNES, CR. 1971 . Nor th America n M iddl e and Upper Ordo vician co nodo nt fa un as. In : W. e. Sweet a nd S.M. Be rgs tro m (eds) , Sy mpos ium on Conodo nt Bios tra tigrap hy . - Geo logical Society of America, M emoir 127 , 163-1 9 3. WICH MANN, R. 19 28. Datos geol6g icos sobre la reg i6n compre ndida e ntre e l Ce rro Nevado y Cerro N ihuil (Provi ncia de Mendo za ). Unpublished rep ort, Dir eccion Nac iona l de Mine ria. Geo logfa e Hid rol ogfa.

60

OLIV ER LEHNERT. MARTIN KELLER and OSVALDO BORDONA RO EARLY ORDOV ICIAN CONODONTS FROM T HE SOUTH ERN CUYANIA TERRANE (MENDOZA PROVINCE. ARGENTINA)

PL ATE I

Striatodontus prolificus 11 et I. Poster o- lateral 2. Poster o-la teral 3. Poste ro-Iateral 4. Poste ro-Iateral 7. Postero-lateral R. Postero-latera l

view, view. view. view. view. view.

IANIG LA IAN IGL A IAN IG LA IANIGLA IANIGLA IA NIG LA

PI 7 10. sample PI 711. sample PI 712 . sample PI 7 13. sample PI 7 14. sa mple PI 7 15. sa mple

Eucharodus parallelus

CAS CAS CA S CAS CAS CAS

57

1995

B ARNES,

I. x 3. x 3. x 3. x 3. x 3. x

230. IR2. 202. 150 . 166. 2 16.

et

ME HL,

19 33) . . . . . . . . . . . . . . .

M EIIL )

sensu

( BR ANSO N

56

5. Lateral view. IANIGLA PI 7 16. sample CAS 3. x 174.

" Drepanod us" grac ilis

( BRA NSO N

et

LI NDST RO M,

1955 s.f.

55

6. Late ral view. IANIGLA PI 7 17. sample CAS 4. x 170.

Iuan ognathus jaanusso ni

S ERPAGLI , 1974

56

9. Posterior view. IANIGLA PI 7 1R. sa mple CAS 5. x 93 .

Scolopodus cf. rex

LI NDSTR OM ,

57

1955

10. Postero-l ate ral view. frag men t. IANIG LA PI 7 19. sa mple CA S 5. x 121. 5. 11 . Lateral view. fragment . IANI GL A PI 720 . sample CAS 6. x I () I) .

Tropodus sweeti

LI NDSTR OM ,

1955

57

.

12. Lateral view. fivecos tate S element. IAN IGLA PI 72 1. sample CAS 5. x 130. 13. Poster ior view. fivecostate S element. IAN IGLA PI 72 2. sa mple CA S 5. x 113. 15. Lateral view. P element. IAN IGL A PI 723. sa mple CA S 5. x 97.

Bergstroemognathu s extensus

55

S ERPAGLI , 1974

14 . Posterior view . Sa e lement . IANIGLA PI 724 . samp le CAS 5. x 117. 19. Latera l view . S eleme nt, IANIG LA PI 725 . sample CAS 5. x 154.

Paracordylodus graci lis

LI NDST RO M,

1955

.

56

16. Lateral vie w. paracord ylodiform e lement. IANIGLA PI 726. sa mple C AS 6. x 170 .

Oepikodus com munis

( E T HINGTON

et

C1 .ARK . 1'J64 )

56

17. Lateral view. P eleme nt. IANIGLA PI 727. sa mple CAS 5. x 170 .

Drepanodus arcuatus

P ANDER,

1856

55

IR. Lateral view, P element, IANIGLA PI 728, sample CAS 5. x 69 .

Scolopodus'l krummi

( LE HNE RT ,

1995)

20 . Posterior view. IANIGLA PI 729 . sa mple CAS 6. x 130.

57

Palaeontologia Polonica. No. 58. 1998

PI. I

62

O LIVE R LEII NERT. MARTI N KELL ER and OS VALDO BORDO NARO EA RLY ORDO VICI AN C ON O DON TS FROM T HE SO UT HE RN CU YAN IA TE RRANE (MEN DOZA PRO VINC E. ARGENTINA)

PL AT E 2

Oepikodu s e me

( L INDSTROi\1.

1955 ) . .. . .

56

I. Lat er a l vie w. P element . IA NI G LA PI 730. sa mp le CAS 7. x 150. 5. Lateral vie w. S ele me nt. IA NIG LA 1'1 73 1. sa mp le CAS 7. x 2 16. 7. Later al view . S eleme nt. IA NIG LA 1'1 732. samp le CAS 7. x 154.

Bergstroemogna thu s exte nsus Serpa g li. 19 74

55

2. Lat eral vie w. M e le me nt. IA NIGLA PI 733. sa m p le CAS 7. x 77.

Periodonjlabellu m 3. 6. 12. 13. 17.

( LI ND STR O I\I.

1955 ) . . .

57

La ter al view. S elemen t. IA NI G LA P I 734. sa mp le CAS 7. x I 13. Latera l view. M e le me nt. IA NI G LA P I 735. sam p le C AS 7. x 109. La ter a l vie w. S e le me nt. IA NI G LA P I 736. sa mp le CAS 9. x 11 7. Po steri or view . S e le me nt. IA NI G LA P I 737 . sa mp le C AS 9. x 170. Lat eral view. P e le me nt. IA NIG LA P I 73H. sa mp le CAS 9. x 130.

Scolopodus'l krummi

L E IINERT,

1995

57

4 . Po ster ior view. IA NI G LA PI 739. sam p le CA S 7. x 146. 9. Po sterio r view. IA N IG L A PI 740. sa m p le CAS 7. x 77.

Fahra eosodu s marath on ensis

( BR AD S IIAW,

196 9 )

56

X. Lat eral view. P e le men t. IA NIGLA PI 74 1. sa mp le CAS 7. x 146.

Paroistodus originalis S ERGEEVA. 1963

.

56

10. La te ra l vie w. o isto d iform e leme nt. IA NI G LA PI 742. sa m p le CAS 9. x 138.

Oistodus aff. lan ceolatu s

P ANDER .

1856

54

11. Lateral v iew . IA NI G L A P I 743. sam ple C AS 9 . x 97.

Errat icodo n sp. . . . . . . .

.

55

14 . Inn e r late ral vie w. M ele me nt. IA NI G LA 1'1 744. sa mp le C AS 9. x 73 .

Pteracont iodus cryptodens

M O UND,

15. Lat eral vie w. IA NI G L A PI 745. sa m p le CAS 9 . x X9. 16. Lat era l view . IA NI G LA PI 746 . sa mp le CAS 9. x 73.

19 65

57

Palaeontologia Polonica, No. 58, 1998

PI. 2

64

OLlVER LEHNERT. MARTIN KELLER and OSVALDO BORDONARO EARLY ORDOVICIAN CONO DONTS FROM THE SOUTHERN CUYANIA TERRANE (MENDOZA PROVI NCE, ARGENTINA)

PL ATE 3

Oistodu s? tablepointensis

S TOUG E,

1984

56

1. Postero-Iateral view, IANIG LA PI 747. sample CAS 10, x 97. 11 . Postero-lateral view, IANIG LA PI 748. sample CAS 10, x 89.

Oistodu s aff. lanceolatus

P ANDER,

1856

56

2. Lateral view, IA NIGL A PI 749 , sa mple CA S 9, x 97. 9. Lateral view, Sb eleme nt, IANIGLA PI 750, sa mple CAS 10, x 89. 16. Posteri or vie w, Sa elem ent , IANIGLA PI 751, sample CA S 9, x 97.

Errati codon 'l balticus D ZIK, 1978 ..

55

3. Poster ior view , IANI GL A PI 752, sample CA S 9, x 146.

Protopanderodu s gra datus

S ERPAGLI ,

1974 . . . . . . . . . . . . . . . . . ..

57

4. Late ral view, IANIGLA PI 753 , sample CAS 10, x 134. 5. Lateral view, IANI GL A PI 754, sa mple CAS 10, x 150.

Drepanoistodu s basio vali s

( SERGEEVA,

196 3)

.

55

6. Lateral view, su berec tiform eleme nt, IANIGL A PI 755, sa mple CAS 10, x 125. 12. Lateral view, ois todi form ele ment, IANIGL A PI 756. sample CAS 10, x 11 3.

Periodon flab ellum

( L INDSTRbM ,

1955 ) . . .

57

7. Lateral view , S eleme nt, IANI GLA PI 757. sample CAS 10, x 97 .

Spinodu s sp. . . . . . . . . . . . . . . . . . .

57

8. Lateral view. frag me nt, IANIGL A PI 758 , sample CAS 10, x 130.

Pteracontiodu s cryp todens

M O UND,

1965

57

10. Lateral view, IANI GL A PI 759 , sa mple CAS 10, x 11 7.

Drepan oistodus forceps

LI NDST ROM,

1955

.

55

1974 . . . . . . . . .

51

.

56

13. Lateral view, oistodifo rm eleme nt, IANIGLA PI 760. sample CAS 10, x 125.

Phosphannulus universalis

M ULLER, N OGAMI

et

L ENZ,

14. IANIGLA PI 76 1, sa mple CAS 8, x 154.

Paroistodu s originalis

(S ERGEEVA,

1963)

15. Lateral view, oistodifo rm eleme nt, IANI GL A PI 762, sample CAS 10, x 125.

Palaeontologia Polonica, No. 58, 1998

PI. 3