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Home , Aspidoceras, Euaspidoceras, Perisphinctidae

AMEGHINIANA ISSN 0002-7014 Revista de la Asociación Paleontológica Argentina Tomo XII Diciembre de 1975 N?4

THE INDO-PACIFIC AMMONITE MAY AITES IN THE OF THESOUTHERN ANDES

By P. N. STIPANICIC', G. E. G. WESTERMANN 2 and A. C. RJCCARDI3

ABSTRACT: Oxfordian Iitho- and biostratigraphy of the Chilean and Argentine Andes is reviewed (P. N. Stipanicic). Within the Chacay Group, the Lower to basal Upper Oxfordian La Manga Formation, below, mostly detrital and biogenic, and the Upper Oxfordian Au- quilco Formation, above, mainly chemical, are distinguished. The La Manga Formation (with Gryphaea calceola lumachelle) is rich in ammonite faunas, particularly of thc upper Cordatum to lower Canaliculatum Zones. In Neuquén and Mendoza provinces of Argentina, the Pli- catilis Zone or Middle Oxfordian has yielded Perísphinctes spp., spp., Aspido- ceras spp., together with Mayaítes (Araucanites ) stípanícfcí, M. (A.) reyesi, and M. (A.) mulai, Westermann et Riccardi subgen. et spp. nov. The first find of Mayaitidae outside the Indo-Pacific province is discussed in light of _plate-tectonic theory.

RESUMEN: La revisron Iito- y bioestratigráfica del Oxfordiano de los Andes de Argentina y Chile (P. N. Stipanicic) ha permitido reconocer dentro del Grupo Chacay: 1) abajo, la Formación La Manga, mayormente detrítica y biogénica, del Oxfordiano inferior-superior basa!, y 2) arriba, la Formación Auquilco, mayormente química, del Oxfordiano superior. La For- mación La Manga (con lumachelas de Gryphaea calceola) contiene abundante cantidad de amonitas, particularmente de las Zonas de Cordatum superior a Canaliculatum inferior. En las provincias de Mendoza y Neuquén,Argentina, la Zona de Plicatilis (Oxfordiano medio) contiene Perispbinctes spp., Euaspidoceras spp., spp., conjuntamente con Mayaites (Araucanites) stipanicici, M. (A.) reyesi, y M. (A.) mulai, Westermann et Riccardi subgen. et spp. nov. El primer hallazgo de Mayaitidae fuera de la provincia lndo-Pacífica es dis- cutido tomando en consideración la teoría de tectónica de placas.

· P·¡¿Ó•¡ e¡·•¡ ¿ÓS•Ó·•¡ Ó S¿°¡7 a·¡ =BFC5 RÓ P•Ó5 PñÓ•¡7 • Department of Geology, Md1aster Univorsity, Hamilton , Ontario, Canadi •.

!l ~Juseo ¿Ó S•Ó·•¡ Naturales, c¡ g¡¡5 PñÓ•¡7

~ 281- THE OXFORDIAN cipal Gypsum" (Schiller, 1912); in Chile OF THE ANDEAN GEOSYNCLINE as Millonaria Formation (Harrington, OF ARGENTINA AND CHILE 1961), Middle Member of the Laguni- llas Forma tion (Aguirre Le Bert, 1960), By P. N. STIPANICIC Midd1e Member of the Valle Grande Formation (Gonzalez and Vergara, 1964),

1. LITHOSTRATIGRAPHY Rio Colina Formation (Gonzalez, 1963), Santa Elena Member of the Nacientes del Oxfordian is well represented within Teno Forrnation (K10hn Giehm, 1960), the Argentine and Chilean part of the and others. Mesozoic Andean Geosyncline where it The lower unit, although showing mi- forms part of the Chacay Group t sensu nar facies variation and varying in thick- Stipanicic and Mingramm in Groeber, ness from O to 220 m, was named La 1951 ), belonging to the Chacayano se- Manga Formation (Stipanicic and Min- dimentary cycle (Groeber, Stipanicic and gramm in Groeber, 1951 ,as "Manguen- Mingramm, 1953). The base is marked se"; Stipanicic, 1966). Formerly known by a disconformity or unconformity (Río as "blue limestones with Grypbaea" Grande Phase) with Oxfordian directly (Groeber, 1929), the formation appears overlying to Middle Callovian 111 outcrop superficially homogeneous beds; Upper Callovian appears to be with brownish-bluish-gray weathering missing in the entire basin except in the colour. Two main 1ithofacies can be dis- Domeyko mountain range (Hillebrandt, tinguished: (a) a nearsbore facies of thick 1970). The Chacay Group is, in turn, un- hard limestones, sometimes arenaceous, conformably overlain (Araucan Phase) by dark grayish weathering b1uish-gray, with Lower to Upper or even cora1s, 1umachelle of Gryphaea calceoia (Stipanicic, 1966, 1969; Stipa- ( Qu.) and scarce ammonites; and (b ) nicic and Rodrigo, 1970). a standard facies,above with bluish-gray The Chaca y Group is divided into two Iimestone with minimal amounts of clas- distinct but intergrading sedimentary units, tic, intergrading upwards into the Auquil- i.e., the lower one is mostly detrital and co Formation by increased interbedding biogenic belonging to the Lower to basal of gypsum, with scarce ammonites, and Upper Oxfordian; the upper one, mainly below predominant1y brownish-gray silts- chemical, belongs to the Upper Oxfor- tone, shales, calcilutite and oolites, with dian. The upper unit has unusual facies more abundant ammonites (Groeber et. homogeneity from 18° S in northern Chi- al., 1953; Stipanicic, 1966). le to 39° S in Neuquén province, consis- The standard facies has been identi- ting of up to 400 m of gypsum and/or fied in the subsurface of Neuquén pro- anhydrite and interbedded stinking whitish vince (named Barda Negra Formation, 1imestones in different proportions. In Digregorio, 1965). In Chile, synchronic Argentina, this unit is known as the sediments in similar facies were given a Auquilco Formation (Weaver, 1931; number of formatianal names (Cecioni Groeber, 1946), formerly also as "Prín- and Garcia, 1960 a, b; Galli and Ding-

- 282- 70° \ SANTIAGO. / - TUPUNGATO - TUNUYAN I í I \k/o--Col-ino I ---34° RANCAGUA _ ! {¿\ - I A SAN RAFAEL t!¡/! 't0 Blonco R/o O,amant.- CURICÓ !.~ T t Aa di Monqo .,1 _ l· R/o Choicos . O ~\ R/o reno. S.onlo Elehol ' •'¡' •• ,.,_0<',-".," _~~~ '" ,,, c.,,, '

TALCA - R/a \ ~I ~.~rgüe

"'0 ~ Mf Osst

v/ti> \ • Ows vw g·yw I I ------36° !

CHILLAN.

Aquada de Campos X (Sierra de Reyes) X Aquodo de lo Mulo

Veqo de lo Veranodo LOS ANGELES R¡'O • J -f'''ó <9. ~o \

.6. Main localities with Oxfordian faunos X Id.• with Movoitidoe

o 50 \\• I 6464 4 NEUQUEN.

Fig. 1. - Importaut Oxfordiao local il.ies, inelnding those wiLh Mayaites (Araucanites) sul-gen . ·eL spp. nov., in ArgenLina and Chile between latitudes 33° and 3908 (eL Sti panicic , 11)66)

- 283- man 1962' Harrington, 1961; Klohn or Plicatilis Zones, but only Plicatilis mrnm, lJ~m.Jm lwm ij~~m~~~r~ ~illl~mm l~m)1 nlmlll~ facies in northern Chile to standard fa- Zone and possibly part of the Cordatum cies, often with andesite flows, in the Zone seems more probable. The upper central latitudes: i.e. Tarros Fm., Chacari- beds, with Gregoryceras toucasianum 11a Fm.,Upper Agua Santa Fm., Dorali- (d'Orb.), G. d. transuersarium (Qu.) , sa Fm., and Upper Rinconada Member Ocbetoceras hispidum (Opp.), Perispbinc- of the Nacientes del Teno Formation, etc. tes (Arisphinctes?) andium Stein., P. (A.?) boebmi Stein., P. (A.?) gleimi

2. BIOSTRATIGRAPHY AND BIOCHRONO- Stein., Mirosphinctes sp., and Euaspi- LOGY OF THE LA MANGA FORMATION. doceras d. perarmatum (Sow.), were placed in the Transversarium Zone (Hil- The La Manga equivalents in northern lebrandt, 1970). The lower Bimam- Chile have yielded airich fauna of the matum Zone is indicated by Decipia (?) Plicatilis and Canaliculatum Zones (Mi- gottschei (Stein.}, Discosphinctes d. lu- ddle and lower Upper Oxfordian) at - cingae (Favre) and Euaspidoceras d. Caracoles (Steinmann, 1881; Stehn, 1923; '. perarmatum, while the upper part of the Leanza, 1947 a) including Ochetoceras zone is indicated b~ Decipia (?) deser- canaliculatum (v. Buch), Trimarginites torum (Stehn), Ocbetoceras d. bispi- arolicus (Opp.), Euaspidoceras d. perar- dum (Opp.}, Campylites d. mexicanus matum (Sow.), E. cbilense Leanza, Pe- (Burckh. ), Euaspidoceras sp. and 1doce- risphinctes healeyi (Neum.) P. andium ras sp. (Hillebrandt, 1970). However, Stein., P. (Arisphinctes) barringtoni several species of the last two assembla- Leanza. A very similar fauna occurs ges are already known from the Canali- further north at Arica, together with culatum and even Pliea tilis Zones of doubtful Progeronia which would indica- Europe (Arkell, 1956; Enay et al., 1974). te Lower Kimmeridgian ( Cecioni and Further south in Chile and Argentina, Garcia, 1960 a, b; Corvalan, 1965; Salas the La Manga Formation ("Manguenses" et al., 1966). Faunal lists of partially beds ) was long regarded as Callovian mixed Middle Callovian and Oxfordian (Groeber, 1918, 1929, 1933; Gerth, faunas from the Santa Ana Formation of 1925; Larnbert, 1956), in spite of some pa- Negreiros (Cecioni and Garcia, 1960 o; laeontological evidence suggesting Oxfor- Cecioni, 1961) need to be reexamined. dian. The small poorly preserved assernbla- In general, the northern Chilean faunas ge from the Santa Elena Region (Iocality appear to be mainly Middle Oxfordian. 19) originally described by Burckhardt In the Domeyko Mountains, 25-26° S, (1900 a) as Athleta Zone and later the lower La Manga equivalents yielded (Burckhardt, 1903) reclassified and dated Gregoryceras (Pseudogregoryceras ) d. Callovian-Oxfordian boundary of Mariae iteni (Jeannet), Campylites (Neopriono- Zone (Spath, 1931), needs to be enlar- ceras) d. benrici (d'Orb.) and Peris- ged and reexamined; the alleged Quens- phinctidae which Hillebrandt (1970) on tedtoceras C'Cardioceras aff. lamberti") page 192 considered to represent Lamberti could be a crushed macrocephalitid accor-

- 284- SIERRA DE REYES EÜROPEAN ZONES VEGA DE LA VERANADA STAGES (Neuquén) ( Mandozo) viroatosoninct es Ironsilorius Fm, MUERTA Fm .. TlHioNIAN VACA MUERTA VA CA } Severa I z on e s ( s 1,) Virqalosphineles Gravesia qravesiana

Hybonolieeros oeck er t KIMMERIDGE a atocost, p s eu aomut ab is (s. str.} Strebliles {SIr. teno it. s. sir, lenuilob,atus Sut n, p ta ty not a

Idoeeras {Sulneria qalar Ir UJ planula 51· Idoe.plan. s,slr. e, z e, Epipeltoeeras bimammolum « ::> Perisphineles· mor t eüi> Ocñetoc er as eanolieulalum o Pe/toeeras Pejloeeras, Euospidoeeras « el:: Pe/loeeros, Euaspidoc eras, ;; C> O Perisphinel (Kranoospl¡ineles) ~ Perisph, (Arisphineles) z .. u, ci Perisphinetes pliealilis « c Mayailes (Aroueon/les l sp. KKKLm88 1\..) P (Prososphineles) :::¡; X ex> '" Mayailes ( ar ouconites ) sp. [ M. (A) mu tai, M. (A) r.ey es¡ « Vl O M. (A) sl/panieiei ..J ~ Cardioeeras cordatum o -' Ouens tedt ocer as mariae

o.: Ouens te d toc er os tamb er t¡ z ::> Pel/oeeros attitet o « o Erymnoceros coronatum > Kosmoeeros ja s on O ...J '" ...J Ir Maeroeephaliles . Siqaloeeros UJ ¡ « ~ . macrocepbatus eallovlense. u o Maeroeepha/¡Ies -' 5.1. macroceph. s. sIr.

BATHONIAN I Several zones z -s ::> u .O.., '" I Se v e r o l zones Sonninia, Ps eo dot oit es Sonrunia, Cñondrocer os « Pseo aot oit es , Emilela CD -' P.N,S. 1974

Fig. 2. - Correlation cliart COI' the Jurasslc sections of Neuquen and Menrloxa Prov inces, A rgenl ina, which have yieldod Mayaites (AraucanitesJ: subgen. et 51'1'. nov. ding to reexamination of the specimen by description of the sections can be found Riccardi (in litt.). The supposed Peris- in the mentioned articles. phinctes d. rotba (Waagen) from the \ a11 Iocalities yielding the new sub- "blue Iirnestones with Grypbaea" descri- genus Mayaites (Araucanites ) described bed by Burckhardt (1900 b) also needs herein (Text-fig. 1), the La Manga FO'r- to be reexamined since the species would rnation overlies unconformably a thin suggest an early Late Oxfordian age for sandy-conglomeratic bed with a rich Rei- the La Manga Forrnation. More recently, neckeidae fauna probably of the early Klohn Giehm (1960) recorded an Ox- Middle Cal1ovian, and grades upwards fordian assemblage from the international into the Auquilco Formation.The two- boundary at 35° S latitude, including fO'ld Iithologic división of the La Manga supposed Quenstedtoceras sp. which, be- Forrnation is consistently present; the cause of its boreal restriction, needs reexa- upper thinner mernber (unnarned ) con- mination, \ the classical Blanco and La sisting of calcarenites and compact dolo- Manga creeks are a of Mendoza Province, mitic limestones with lumachelles of the beds irnmediately underlying the Au- Gryphaea d. calceola ( Qu.) but few quilco Forrnation (or "Principal Gyp- ammonites, and the lower member sum") were demonstrated to belong in (unnarned ) richer in clastics, coquinoid the Plicatilis-Cordatum Zones by the pre- limestones and oolites, with the siltsto- sence of Peltoceras (Peltoceratoides) d. nes yieldingabundant ammonites. constantii (d'Orb.), Euaspidoceras (Neas- pidoceras?) sp., Perispbinctes (Kranaos- Vega de la Veranada (from top) pbinctes ) d. decurrens (Buck.), and P. 3 m: Unfossiliterous (Arisphinctes) spp. (Stipanicic, 1951). 4 m: Gryphaea d. calceola (Qu.) Subsequcntly, Stipanicic and Mingramm Euaspidoceras cbilense Leanza E. aleantbeen (Buck.) (in Croeber, 1951; Groeber et al., 1953; E. aff. loricatum (Bean, M. S.) Stipanicic, 1966) recorded for the first E. (Clambites) sp. time in South America the presence of 'E. spp. Mayaitidae in similar associations, parti- Peltoceras (Peltomorpbites ) cularly at Vega de la Veranada, Neuquén boplopborus (Buck.) (37° 10' S/69° 55' W), and Aguada de Perispbinctes (Prososphinctes) sp. Campos, Cañada and Quebrada Honda P. (Kranaospbinctes ) sp. de la Buitrera (36° 50' S/69° 50'W) in Mayaítes (Araucanites ) sp. the Sierra de Reyes, Mendoza. Recently, Plicatilis Zone and ? upper Riccardi found this assemb1age also in Cordatum Zone. Aguada de la Mula, south of Aguada de Aguada de Campos and Cañada Hon- Campos. Unfortunately, the collections da, eastern slope of Sierra de Reyes of Stipanicic and Mingramm, stored at (from top). Yacimientos Petrolíferos Fiscales, were partia11y destroyed by fire, and only a 7-10 m: large Peltoceras 16 m: Grypbaea d. calceola part cou1d be saved which will be des- Perispbinctes spp. cribed in the near future. The detailed Euaspidoceras spp. - 286 PeZtoceras spp. indude ·a11or part oí the Lower Oxfor- Mayaites t Araucanites ) sti- dian (Mariae and Cordatum Zones). The panicici subgen. et sp. nov. en tire Lower Oxfordian seems to be pre- ? Goliatbiceras sp. (specimen sent in the Santa Elena are a ("Rincona- lost) da Superior";but the lost specimen of Aguada de la Mula, Sierra de Reyes. Quenstedtoceras needs confirmation) and According to Riccardi, the faunal succe- possibly at Arroyo Blanco; the section ssion is as follows: begins with basal Cordatum Zone at Rio 1.10 m: Perispbinctes (Arispbinctes) del Cobre, Barda Blanca, Poti Malal, Va- spp. ca Muerta, et al., and possibly at the top 7.40 m: Euaspidoceras aff. uiaageni Spath of the Cordatum Zone in the thinner Aspidoceras? aff. obesum Spath section of Sierra de Reyes and Vega de Perispbinctes (Dicbotomites ) la Veranada. The interval yielding Ma- d. uiartee Bukowski yaites (Araucanites ) subgen. nov. clearly Mavaites (Araucanites) mulai belongs in the Plicatilis Zone, and may subgen .. et sp. nov. M. (A.) reyesi subgen. et sp. extends downward into the upper Cor- nov. datum Zone. M. (A.) n. sp.? The Auquilco Formation is Oxfordian 3.5 m: Gryphaea sp. in the en tire Argentine-Chilean Basin and Reineckeia spp. evidence for the inclusión of Lower Quebrada de la Buitrera, western slope Kimmeridgian in northern Chile (Cecio- of Sierra de Reyes (12-14 m). ni, 1961) and the Domeyko mountain lower 1-10 m: range (Hillebrandt, 1970) is inconc'usi- (Arisphinctes) ve. The "Principal Gypsum" is clearly spp. pre-Kimmeridgian; the base intergrades Peltoceras spp. Euaspidoceras sp. with the La Manga Formation of the Mayaites (Araucanites) sp. lower Canaliculatum Zone, while limesto- nes interbedded in the upper part have The above assemblages from the Sierra yielded Perispbinctes andium Stein, (Gon- de Reyes are regarded as time-equivalent zalez, 1963) indicating the same zone, to those at Vega de la Veranada, i.e. Plicatilis and ? upper Cordatum Zones. The oldest beds unconformably overlying the Auquilco Formation occur at Chacay Melehue and Rahueco where they have 3. CONCLUSIONS yielded Nebrodites pressulus Leanza, Ido- The La Manga Formation and lateral ceras spp., Aspidoceras sp., Euaspidoceras equivalents belong consistently to the aja» Leanza, and Streblites oxynotum Plicatilis (entire) and the lower Canali- Leanza, (1946, 1947 b), indicating basal culatum Zones, respectively Middle and Kimmeridgian (Platynota Zone) or even lower Upper Oxfordian. Where maxi- uppermost Oxfordian (Galar Subzone) mally developed, the formation may also (Stipanicic, 1966, 1969).

- 287- SYSTEMATICS remain unsolved, with the Callovian Eucycloceratidae Spath most recently By G. E. G. WESTERMANN suggested as possible ancestors, rather and A. C. RICCARDI than the Pachyceratidae (Westermann, 1973 ). The quite unique geographic di s- Superfamily STEPHANOCERAT ACEAE tribution has been the focus of apprecia- Neumayr, 1875 ble attention and was most competent1y Family MAY AITIDAE Spath, 1928 discussed by Spath (1933) and Arkell (1956). One of us (G. E. G. Wester- DISTRIBUTION mann) has recently examined the occu- In this family, Spath (1928, p. 222) rrences in Kenya and found the most included the late Oxfordian macrocepha- eastern one in Papua, New Guinea. Iitid -homeomorphs of the Indo-Pacific The known .occurrences of Mayaitidae faunal province (or realm) Mayaites, have been plotted on the "pre-dríft" Epimayaites, Dbosaites, Parypboceras, ]urassic reconstruction of Gondwanaland Prograyiceras, and (?) Grayiceras, a11his by Seyfert and Sirkin (1973) (Text- genera. The apparently sudden appearan- fig. 3) which appears to be most consis- ce and the phyletic origin of the family tent with recent geological, geophysical

·y····s:: ..

..": :-

'. '7 ~:..

...:'...:..:::<::.:...:.'-.:,.

Fig. 3. - Geographic distribution of Mayaites plotted on lhe « pr e-dr-ift » Gondwanaland as reconslructed by Seyfert and Sirkin (1973), with land-soa distribulion added

- 288- and palaeontological data on the area of (Waagen, 1873-5; Spath, 1927-33); (8) the Indian Ocean or Sinus Australis of in the Sula Islands occur Epimayaites, Tethys (d. Westermann, 1975, p. 34). Parypboceras and Prograyiceras, together From West to East, (1) Arkell (1956, with what appears to be a new subgenus p. 318) has recorded the most northerly of Perisphinctes affiliated to Kranaos- African occurrence from the Plicatilis pbinctes, and ? Peltoceratoides (Boehm, Zone of Daua Valley in northern Kenya; 1907) in what Arkell (1956) believed (2) from the Mombasa atea, he (p. 323) to be Plicatilis to possibly upper Cerda- identified one assemblage with Epima- tum Zone; (9) 20 km SW of Telefolmin yaites and Prograyiceras together with in t:he Western Highlands of Papua New the Perisphinctes subgenera Arispbinctes Guinea is a mountain slide from which and Kranaospbinctes, and another with Papuans brought a large (derived ) fauna Mayaites, Epimayaites and Dbosaites, and to the Telefolmin hospital, including the dated both as Transversarium Zone (no- Sub Islands (W ai Galo) mayaitids assem- te however that Arkell, 1956, usualIy re- blage. Significantly, Mayaitidae are ab- garded Transversarium and Plicatilis Zo- sent from the Kranaospbinctes beds of nes as time-equivalent); (3) fram Tanga japan (Sato, 1964), but Oxfordian is in northeastern Tanzania, Tornquist unknown fram the southwestern Pacific ( 1893) described a suite of Mayaites (New Caledonia, New Zealand). The species which was associated with P. known distribution, therefore, does not (Kranaospbinctes) and Euaspidoceras, contradict the possibility of a southern and dated as (? Cordaturn-) Plica tilis faunal route for mayaitids, either around Zone by Arkell (1956, p. 328); (4) the Gondwanaland vía New Guinea al' more entire family is richly represented in Ma- directly thraugh a possible passage bet- dagascar prabably ranging from the (?) ween southern Africa and Antarctica. late Cordatum to Transversarium Zones, However, with taxonomic difference at as most recently profusely figured by the subgeneric level, no definite conclu- Collignon (1959); (5) the Dhosa oolite sion can be drawn at this point. of Cutch at the Pakistano-Indian border A direct faunistic connection of the has borne the most complete assemblage southern Andes area with the "Ethiopic- of Mayaitids (all genera except the du- Indo-Malagassi faunal province" vía the bious Grayiceras) which seem to range Mozambique Channel of a separating from the probable Cordatum Zone (Ma- Gondwanaland has recently been sugges- yaites subkobyi Spath with Peltoceratoi- ted for the Upper Jurassic by Cecioni des) to the Bimammatum Zone of the and Charrier (1974). This is mainly Kantkote Sandstone bearing Epimayaites based on the supposed common occurren- and Prograyiceras with the "acme" in the ce of Gryphaea balli (Stefanini ). Transversarium Zone (Waagen, 1873-5; Spath, 1927-33); (6) the Attock District TAXONOMY north of the Salt Range and (7) Spiti in the central Himalayas have yielded a The five to SlX mayaitid "genera" number of poorly descríbed mayarrrds appear to fall into two groups, i.e. the - 289- large Mayaites and Epimayaites remaining ras appears to be more frequent than involute and tending to become smooth previously assumed by Spath (1928), on the 60dy cham6er, and the smaller and apparent macroconchs and micro- Parypboceras, Prograyiceras, (?) Dbosai- conchs appear to be always closely asso- tes, and ? Grayiceras in which the adult ciatecl. It is therefore suggested to classi- body chamber becomes evolute and re- fy not only Epimayaites but also Pary- mains ornate. There is strong indication pboceras and the very similar Prograyi- that the former are macroconchs 01' fe- ceras as subgenera of Ma)'aites; this would male shells and the latter the microconchs also conform to the Treatise classification or male shells, with some yet unknown of the Macrocephulitidae (Arkell, 1957, correspondences within the family, as p.L293). suggested by Callomon (1963, p. 33). In the Treatise (Arkell, 1957, p. L Genus ZMkMVeRd Spath, 1924 297), Mayaites and Epimayaites were re- Subgenus McMfOM[VeRd garded as subgenera of a single genus; \l(!estermann et Riccardi, subgen. nov. Epimayaites was said to be distinguished TYPE SPECJES: M. (A.) stipanicici sp. by the projected ribbing and the simpler nov. septal suture. In fact the sutures are of similar complexity and their diagnostic DIAGNOSIS: Mayaitids with obvolute whorls ( occluded umbilicus ), smooth difference is the shape of the EjL saddle flanks, and septal suture as in Mayaites and of the saddle envelope which is s. s. almost radial in Mayaites and convex in DERIVATIONOi\HNIS: Derived from the Epimayaites (Text-fig. 5). In both, E Araucanian Indian people of the central tends to be deeper than L and the U-lobes to southern Andes and Patagonia. small and raised with U2 ("2nd lateral") much shorter than L ("1st lateral"). DrSTRmUTION: Plicatilis (? Upper Cor- datum) Zone of Argentina. However, the taxonomic consis tency of the sutural characters will have to be DrSCUSSION: The occluded umbilicus is thoroughly studied in conjunction with unique among Mayaitidae and the suture the other morphological features to re- . is of the relatively "normal" type of Ma- solve the taxonomic problern within this yaiteI s.s., rather than as in Epimayaites. family which no doubt is mostly owing Since forms resembling mayaitids with to the renowned taxonornic "splitting" smooth flanks arose independently seve- of Spath (1927-33). Incomplete Pary- ral times (see below) -and mayaitids pboceras and Prograyiceras closely re- are known homeomorphs of Callovian semble immatures or nuclei of Mayaites macrocephalitids--, the family relations- and Epimayaites as evident from the re- hip of M. (Araucanites ) is not entirely cent inspection by one of us (G. E. G. certain. However its Middle (or early Westermann) of the entire .collection Upper) Oxfordian age strongly supports studied by Boehm (1907), deposited in this classification since all known homeo- the Geological Institut of Utrech. Also morphs of possible affinity are latest Ox- the probable- microconchiate Parypboce- fordian to ~arly Kimmeridgian.

- 290- PLATE 1

Fig. 1, Zss·w .Msus·w/ ·s·u·u· West, el Rice., subgen. et sp. nov., holotype, complete specimen , lateral view, X 0.75 (MLP 12240). Plicatilis (' U. Cordatum) Zone, loeality Xl, Aguada de Campos, Sierr-a de Reyes.

- 291- Several mayaitds are known which gasear (Basse and Perrodon, 1952, p. appear to diHer from M. (Araucanites) 60). A similar large involute specimen only or mainly in the involute, not ob- with smooth outer whorls was already volute, umbilicus; all seem to be based described by Noetling (1896, p. 14, pl. on single specimens only and are there- 11, fig. 1) under "Nacrocepbalites poly- fore rare accessories to the usually abun- pbemus Waagen" and identified with dant more strongly ribbed forms. "Ste- Mayaites maya by Spath (1927-33, p. pbanoceras" arenosum Waagen (1875) 233 ). from the Dhosa _Oolite of Cutch has On the other hand, there are several blunt primaries (smoother on the flanks la test Oxfordian to early Kimmeridgian than figured ) and was tentatively placed Perisphinctidae genera and sub genera in "Mayaites ? (Parypboceras )" by Spath which closely resemble the above mayai- ( 1927 -33, p. 232); the septal sutu re tids in the involute coiling (but not appears to be similar as in Epimayaites. obvolute) , whorl section and reduced However, Collignon (1959, Hg. 248) ribbing. Among the Pictoniinae are Bal- figured a M. (Epimayaites ?) arenosum ticeras Dohm and Ringsteadia (Vineta) with smooth flanks from the "Lower Dohm (cf. Geyer, 1961) and among Argovian" (? Cordatum-Plicatilis-? Trans. the Aulacostephaninae, I nooluticeras Sal- versarium Zone) of Madagascar, again feld and Epicepbalites Spath. All differ with the highly raised umbilical lobes of in the perisphinctid septal suture with thar subgenus. Epimayaites subarenosus retracted, not raised, umbilical lobes and Spath (1931, pl. 121, fig. 7), also from 1nvoluticeras has also bullae-like primaries the Dhosa Oolite, was defined in the on the umbilical shoulder. Of particular plate description only as "characterized interest because of its distribution is Epi- by prorsiradiate ribs, confined to peri- cephalites, based 011 "Macrocephalites" phery, the smooth sides and the high, epigonus Burckhardt (1906) from the almost perpendicular, umbilical wall". "Ldoceras beds" of north-central Mexico, This is possibly identical with his earlier and reported in similar association from M. ?{lff. arenosus of which he had only New Zealand (Arkell, 1956, p. 455). figured the suture (pl. 28, Hg. 4). How- The holotype, the single known Mexican ever, the umbilicus of the phragmoco- specimen, differs from Araucanites also ne is relatively large (18 % ); the septal in the rounded umbilical slope of the suture again resembles that of Epimayai- involute, not obvolute, whorls; in fact it tes with high umbilical elements, clearly seems aHiliated to the almost Haploceras- differing from that of Arauconites. Epi- like Subneumayria ordonezi (Burckhardt ) mayaites excentricus Spath (p. 239) is witb which it is associated.The even la- based on a large specimen from the Kant- ter (late Lower Kimmeridgian Haploce- cote Sandstone, Bimammatum Zone, and ras [ialar beds) Procraspedites mazapilen- closely resembles the "species" based on sis (Burckhardt) from the same section much smaller incornplete phragmocones is even more compressed than M. (Arau- mentioned above; it was also recorded canites ) stipanicici and differs again in the from the Transversarium Zone of Mada- retracted simpler septal suture; it was

- 292- PLATE II

N \.O \.N

Figs. 1-2, Zss·w .Msus·w/ ·s·u·u· West , et Rice .. subgen. et sp. nov ., body chamber removed, lateral and ventral views, X 1 (MLP 12240). Plicatilis U D. Cordatum) Zone, locality Xl, Aguada de Campos, Sierra de Reyes. probably correctly placed in the '

Diarneter Whod heigl,t 'Vidth n°••· dinrneter

Phragmocone ...... 114 DD 52 O 75 43 32 O Body Ohamber , " ...... 172 c.SO c.70 0/(13 int. mould)

- 294- PLATE VVV

N \D VI

1

Figos. 1-2, d¡¡•Ó 0P¡·¡•Ó1 ÓÓ• West . el Ricc., ,ul'gen. el 'p. DOV., holotypc, sligohll:" crushed incomplete phragomoconc, laternl and ventral view s. X) <\IJ.P )22·~1). Ptica+ilis (~ U. Cordntum) Zone. Aguada ele la ~Illla, Sierrn de Reyes. .~..U":- :::,: U".. -!~}~::~~:.: e

a b d

Fig, 4, - Cross-sectious L1I1'o.ll¡;11pllragmocooc (wl.ite) n nd boj)' chu mber (grey) of' : a, Mayaites (Arau- canites) stipanicici sp. nov. holotjpe (MLP 12UO); b, M. (A.) reyesi sp. nov., holotype and pa- raLypes (MLP 122H-4:l); e, M. (A.) mulai SI'. 1101., hololype (MLP 12217) and d, M. (A.) SI'. nov.i' 1 (MLP 12246). c. X 1/2.

Mayaites (Araucanites) reyesi DESCRIPTION: The phragmocone is \'ijestermann et Riccardi, sp. nov. compres sed subglobular, with inflated ovate whorls which are about as high as Pl. III, figs. 1-2; Pl. IV, fig. 1; Pl. V, figs. 1-2; Text-figs, 4 b, 5 a broad. The umbilicus is highly involute on the internal mould, commencing at least alread y at about 30 mm diarneter, HOLOTYPE: The slightly crushed in- and the shell was very probably obvolute complete phragmocone (MLP 12241), with occluded umbilicus. The ornament internal mould, from La Manga Forma- of the phragrnocone consists of fine den- tion, Aguada de la Mula, Sierra de Reyes, se, somewhat prorsiradiate ribs on the Mendoza. outer third of the flank which pass con- lJIAGNOSIS: Large shell with inflated vexly over the rather broad ventre; there subovate whorls; ribbing fine and dense, are 20-25 ribs per quarter whorl. The smallest specimen, at about 35 mm dia- obsolete 011 outer whorl. meter, has also several ver y faint radial MATERIAL: Two incomplete phragmo- swellings on the inner flanks (internal cones; probably two complete shells with rnould ) which then disappear entirely. somewhat crushed phragmocone and one The ornament becomes obsolete on the nucleus. All fram Aguada de la Mula. last half whorl of the phragmocone so that no ribbing 18 visible on the two AGE: Plícatilis (? Upper Cordatum) large complete specimens. The septal su- Zone. ture is cornplicated (Tex-fig, 5 a), with - 296- PLATE \o

Fig. :3 Z ss·w .Msus·w/ ww· ""eslo el Rice .. subgen. el sp. no,"., complete specimcn , lntcrnl view , X : ./VYa 12242). Plicatilis (? L. Cordatum) Zone, Aguada de la ~Illla, Sierra de Reyes

- 297- a McMfOM[ VeRd

ZMkMVeRd s.s.

e i

~ RaVZMkMVeRd

Fig. 5. -- Externa l septul sutures of: a, Mayaites (Araucanites) reyesi sp. nov., holotype (MLP 12241); b , Z5 (A.) mulai sp. nov., holotype ¡MLP 1224.7); e, M. (Mayaites) rotundus Sl'alh (1927-33, pl. 44, fig.7); d, Z5 (Epimayaites) evolutus Spath (1927-33, pl. 37, fig. 5).

E slightly deeper than L, a subsymme- simple with relatively somewhat larger trical E/L saddle, a small raised U2 U2, but otherwise similar as in the adult ("second lateral"), reduced additional (Text-fig.5a). umbilical elements, and an almost straight The body chamber, 3/5 to 3/4 whorls and radial saddle envelope. On the nu- long, remains obvolute to extremely in- cleus {D = 40 mm ), the- suture -is rather volute (internal mould ). It becomes so- - 298- PLATE V

2

Figs. 1-2, Mayaites (Araucanites) reyesi \Vesl. et Rice., subgen. el sp. nov., juvenil e phragmocone, lateral anel ventral views, X 1 (MLP 12243). Pl icaf.ilis (? Cordatum) Zone, Aguada de la Mula, Sien. de Reyes ; 3-4, Mayaites (Araucanites) 'p, nov. ? J, damaged adult phragmocone, lateral and ven- lral ,iel\' , X 1 (MLP ]22-11\), Same nge and locality. - 299- mewhat depressed ovate to subtriagonal the end of the adult phragmocone. M. in section and ends in a simple obliquely (A.) mulai sp. nov. is much smaller. inclined peristome, with slight lateral The external septal suture closely re sem- constriction on the internal mould. bles those of Mayaites s.s. at different COMPARISON:This species differs from stages of growth (d. Spath, 1927-33, pl. M. (A.) stipanicici sp. nov. in the more 28, fig. 5; pl. 34, fig. 7; pl. 44, fig. 7). inflated rounded whorls and the finer ribbing which becornes obsolete before MEASUREMENTS: (in mm):

T•¡ÓÓ 5'::9:.: height, Width Umhilicn) d iaruetcr

Hol otype phragrn ...... 111 59 c.50 (5 int. mould) MLP 12243 phragm ...... 46.5 26.3 25.<1 (c. 2 int. monld) 36 19.5 20 MLP 12244 aperture ...... c.145 80 76+ (c. 3 in t. rnou ld ) MLP 122-l2 apertur e ...... 150 c.80 c.81 c. O

Mayaites (Araucanites) sp. nov. ? I but can be seen to be complicated and Pl. V, figs. 3-4;Text-fig. 4 d similar as in the other Araucanites; E is deep, while the umbilical lobes are The well preserved damaged adult small and raised, and the saddles follow phragrnocone (MLP 12246) from Agua- a straight radial envelope. da de la Mula, Sierra de Reyes, Mendoza, is large and subspherical. Tbe braad ob- COMPARISON: This phragmocone re- volute whorls have a section resembling sembles M. (A.) stipanicici sp. nov. a catenary curve, the shell occluding the except for the much stronger inflation umbilicus. The periphery of the begin- and the somewhat denser ribbing; M. ning of the last whorl at 65-75 mm dia- meter (?recrystallized shell ) has blunt (A.) reyesi sp. nov. has also more corn- rather dense and somewhat prorsiradiate pressed whorls and a somewhat finer complete ribs, while the flanks are enti- ribbing. It is possible, that this is a rely smooth; the end of the phragmocone mete variant of cne of these species, ar 85-95 mm diarnerer has still traces of parricularly of M. reyesi. peripheral ribbing on the internal mould. The septal suture is poorly preserved MEASUREMENTS(in rnrn }:

Dta meter 'Worl height wuu. :a••·¡ dinmctr r

phr ag . 101 54 69 O

Mayaites (Araucanites) mulai DIAGNOSIS: Small shell with highly Westermann et Riccardi, sp. nov. involute (? obvolute ), slightly compre- Pl. VI, figs. 1-2; Text-figs. 4 e, 5 b ssed subrectangular whorls, becoming ovate with long body chamber; ornament HOLOTYPE: The complete internal extrernely fine and dense, restricted to mould (MLP 12247), collected in the periphery of phragmocone. La Manga Formation, Aguada de la Mu- la, Sierra de Reyes, Mendoza. MATERIAL: The holotype. - 300 PLATE VI

VJ o•....•

Figs. 1-2, Zss·w .Msus·w/ s· West. el Iticc., subgen el sI'. nov., holotype, complete specimen, lateral aud vontrn l v iews, Xl plLP 122<17). Plicalilis (? U. Cordaturn) Zone, Aguada de la Milla,Sierru de Reyes. AGE: Plicatilis (? Upper Cordatum) ovate by increasing convergence of the Zone. flanks. The umbilicus of the internal mould rernains highly involute (?obvolu- DESCRIPTION: The entire adult shell, te in the shell ), possibly except for the with 4/5 whorls long body chamber; is very end. The peristome seems to be only 110 mm in diameter. The exposed indicated on the Ieft side of the internal end of the phragmocone, at about 60 mrn mould as a sinuous line with shallow diameter, has a somewhat compressed, ventral sinus.Faint undulations are vi- rounded subrectangular whorl section, sible in oblique 1ight on the periphery of with slightly convex flanks and broadly the beginning of the body chamber only; rounded ventre. The umbilicus of the the remainder is entirely smooth. internal mould is ver y small (c. 7 % of D) but with relatively well rounded COMPARISON: The other species of M. sboulder in comparison to the other (Araucanites) are consistently appreciable species of the subgenus; test remains in larger, have a clearly occluded umbilicus the umbilicus, however, attest to a thick and a shorter body chamber (? with dif shell which left only a minute cylindrical ferent peristome). The possibi1ity that umbilicus (4-5 % of D), if it was not occluded.Shell remnants on the peri- this is a microconch, while the other phery oí the phragmocone end bear dense specimens are macroconchs, exists; how- and blunt somewhat prorsiradiate ribbing. ever, the simi1arity in the body chamber The somewhat corroded internal mould which is also involute and s11100th seerns of ihe last whorl is essentially smooth. to argue against it. Because of the pro- The last several septal sutures are bable absence of complete occlusion and approximated indicating that the speci- the Ionger body chamber with perhaps men is adult. The last suture has a deep different peristome, this form is somewhat E, a sub-syrnmetrical E/L saddle; L is tentatively placed in the subgenus Arau- slightly shorter than E, U2 ("second la- teral") is somewhat more than half the canites. Because of the possible presence size of L and raised, the rernaining urnbi- of an umbilicus, there is qui te close re- lical elements are not well preserved but semblance to the srnooth-sided involute can be seen to be aligned along the mayaitids from the Indo-Pacific faunal straight radial saddle envelope. There is province or realm discussed above under good resernblance to the suture of M. (A.) reyesi sp. nov. the subgeneric heading. The body chamber is slightly more MEASUREMENTSOF THE HOLOTYPE (in than three-quarters whorl long, becoming mm ) :

Diameter Whnrl óÓ•ñó wuu, Umhilical d ínmeter

ph rag m . c. 63 =C 31 (c. 3-4 in t, mould ) apert . 110 59 8 C: (6.5 int. nrould)

ACKNOWLEDGEMENTS age deterrnination of an ammonite; Lic. M. U1iana, Yacimientos Petrolíferos Fis- We thank Dr. J. H. Callomon, London cales, who enabled A. C. Riccardi to vi- University, for advice on the current sit the fossil locality of Aguada de la zonation of the Oxfordian and for the Mula and, together with Lic. S. Darnbo-

- 302- renea and M. Manceñido, Museo de Cien- Mus. La Plata, Seco Ceol. y Miner. II: 1-136, pl. 1-32. La Plata. cias Naturales de La Plata, participated -1900 b. Coupe géologique de la Cordillere in the field work; and Dr. J. M.De entre Las Lajas et Curacautín. - Ibidem III: Giusto, also from Yacimientos Petrolífe- 1-102, pI. I-X,'CVI. La Plata. ros Fiscales, who has helped to locate old -1903. Beitriige zur Kenntnis der Jura- und collections. Work in the field and labo- Kreideformation del" CordilIere. - Palaeonto- ratory of G.E.G.W. and A.C.R. was fi- graphica L: 1-144, pl. I-XVI. Stuttgart, -1906. La faune jurassique de Mazapil.- Bol. nanced by the Consejo Nacional de In- Inst. Geol. Mexico 23: 211 pp., pl. I-XLIII. vestigaciones Científicas y Técnicas de la México. República Argentina and the National CALLOMON, ]. H., 1963. Sexual Dimorphism in Research Council of Canada. Jurassic Ammonites. - Trans.Leicester Lit. Phil. Soco LVII: 21-56, pl. I, fig. 1-9. Lei- DEPOSITORY: The material is deposited cestero in the collections of the División de Pa- . CECIONI, G., 1961. El Titónico inferior marino leozoología Invertebrados, Museo de Cien- en la Provincia de Tarapacá y consideracio- cias Naturales, La Plata, Argentina, the nes sobre el arqueamiento central de los An- des.- Univ. Chile, Fac. Cs. Fís. y Matem., numbers prefixed MLP. Comun. Esc. Geol. Año 1, N~ 3: 1-19, 2 figs. Santiago de Chile. CECIONI, G. & CHARRIER, R., 1974. Relaciones REFERENCES entre la Cuenca Patagónica, la Cuenca Andina y el Canal de Mozambique. _. Ameghiniana AGUIRRE LE BERT, L., 1960. Geología de los XI (l): 1-38, 1 lám., 6 figs. 3 cuadros. Bue- Andes de Chile Central, Provincia de Acon- nos Aires. cagua. - Lnst . Lnu. Geol., Bol. 9: 68 pp., 6 grá- CECIONI, G. & GARCÍA, F., 1960 a. Observa- ficos, 1 mapa. Santiago de Chile. ciones geológicas en la Cordillera de la Cos ta ARKELL, W. ]., 1956. [urassic Geology 01 the de Tarapacá.- Inst. Inu. 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- 304 SCHILLER, W., 1912. La Alta Cordillera de San -1969. El avance en los conocimientos del jurá. Juan y Mendoza y parte de la provincia de San sico argentino a partir del esquema de Groe- Juan. - An. Min. Agric., Seco Geol., Mineral. ber. - Rev. Asoc. Geol. Arg. XXIV (4): 367- y Miner. VII (5): 5-68,27 láms., 1 fig. Bue- 388. Buenos Aires. nos Aires. STIPANICIC,P. N. & RODRIGa,F., 1970. El dias- SEYFERT,C. K. & SIRKIN,L. A., 1973. Earth trofismo jurásico en Argentina y Chile. - IV History and Plate Tectonics, an Introduction to [orn. Geol. Arg., I1: 353-368. Buenos Aires. Historical Ceology. 504 pp. Harper & Row. TORNQUIST,A., 1893.Fragmente einer Oxford- SPATH, L. F., 1927-33. Revision of the jurassic fauna von Mtaru in Deutsch. Ostafrica.- fauna of Kachh (Cutch).-· Jahrb. Hamburger Wiss. Anst. 10: 264-288. Palaeont, Indica, N. S., IX(2): 1-945, pl. WAAGEN,W., 1873-75. Jurassic fauna of Kutch. CXXX. The Cephalopoda. - Palaeont. Indica IX (1): STEHK, E., 1923. Beitriige zur Kenntnis des 1-247, pl. I-LX. Bathonien und Callovien in Südamerika. - N. WEAVER,C. E., 1931. Paleontology of the Ju- u. Min., Ceol. u.PoI., B. Bd. XLIX: 52-158, rassic and of West Central Argen- pl. 1-8. Stuttgart. tina.-Univ. Washington, Mem. 1: I-XV, 1- STEINMANN, G., 1881. Zur Kenntnis der Jura 469, pl. 1-62. Seattle. und Kreideformation von Caracoles (Bolivia). - N. Jb. Min., e-a. u. Pal., B. Bd. 1: 239- WESTERMANN,G. E. G., 1973. Evolution and 301, Stuttgart. Taxonomy of Pachyceratidae and Mayaitidae, STIPANICIC,P. N., 1951. Sobre la presencia del suggested by septal patterns (Juras sic Ammo- Oxfordense superior en el arroyo de la Manga nitina).-XXII Int. Ceol. Congress, India (Provincia de Mendoza ).- Reo. Asoc. Geol. 1964, Proc. 8: 1-15, figs. 1-4. New Delhi. Arg. VI (4): 213-239, lám. I-III. Buenos Aires. -1975. Bajocian arnmonoid fauna of Tethyan -1966. El Jurásico en Vega de la Veranada affinities from the Kambe Limestone Series (Neuquén), el Oxfordense y el diastrofismo of Kenya and implications to plate tectonics. divesiano (Agassiz-Yaila ) en Argentina.- - Newsl. Stratigr. 4 (1): 23-48, 2 pl. Rev. Asoc. Ceol. Arg. XX (4): 403-478, lám. I-XI. Buenos Aires. Manuscrito recibido 20jXlj74.

- 305-