Chondrichthyan and actinopterygian remains from theLower Permian Copacabana Formation of Bolivia

C H O N D R I C H T H Y A N A N D A C T I N O P T E R Y G I A N R E M A I N S F R O M T H E

L O W E R P E R M I A N C O P A C A B A N A F O R M A T I O N O F B O L I V I A

by

DAGMAR MERINO-RODO * & PHILIPPE JANVIER **

ABSTRACT

Two horizons of the marine Lower Permian (Leo- nardian) Copacabana Formation have yielded fish remains, on the south-western slope of the Jacha Kha- tawi Hill, Yaurichambi, La Paz department, Bolivia. This fish fauna consists of teeth and scales of chondrichthyans (Eugeneodontida, Petalodontida, ? Bradyodonti, Elasmobranchii) and actinopterygians (? Plastysomidae). The Eugeneodontida are represented by a new species of a large Agassizodontidae, Parahelicoprion mariosuarezi n.sp., based on a large symphysial tooth series which resembles P. clerci from the Lower Permian Arta beds of the Urals. The Petalodontida are represented by a fragment of a large symphysial tooth which may be referred to the pristodontid genus Megactenopetalus, known else- where from the Lower Permian of the U.S.A. and China. Some isolated crushing teeth may questionably be referred to a bradyodont, possibly Helodus or Lagarodus. Some elasmobranch teeth of ~ Clado- dus ~ type also occur in this locality. Some hemispherical teeth of ~ phyllodont )) type and some scales are tentatively referred to the actinopterygian family Platysomidae. These findings are the first record of determinable marine Permian fishes in the Andean region of South America. The overall composition of this fauna agrees fairly well with the fish fauna known from the Marine Lower Permian of United States and eastern Asia.

RI~SUMI~

Deux horizons de la Formation de Copacabana (Permien inf6rieur marin, L6onardien), affleurant sur le versant sud-ouest de la colline de Jacha Khatawi, Yaurichambi (D6partement de La Paz, Bolivie), ont livr6 des restes de poissons, essentiellement des dents et des 6cailles de Chondrichthyens (Eugeneodontida, Petalodontida, ? Bradyodonti, Elasmobranchii) et d'Actinopt6rygiens (? Platysomidae). Les Eugeneo- dontida sont repr6sent6s par une nouvelle esp6ce d'Agassizodontidae, Parahelicoprion mariosuarezi nov. sp., bas6e sur une s6rie de grandes dents symphysaires qui ressemble ~ celle de P. clerci des couches d'Arta (Permien inf6rieur) de l'Oural. Les Petalodontida sont repr6sent6s par un fragment d'une grande dent symphysaire attribu6 au Pristodontid6 Megactenopetalus, connu ailleurs dans le Permien inf6rieur des U.S.A. et de Chine. Quelques dents broyeuses isol6es pourraient appartenir ~ un Bradyo- donte proche de Helodus ou Lagarodus. Quelques dents d'I~lasmobranche de type (( Cladodus ~ pro- viennent 6galement de ces horizons. Quelques dents h6misph6riques de type ~ phyllodonte ~) et quelques 6cailles sont attribu6es ~ un Actinopt6rygien Platyso- mid6. Cette faune repr6sente la premi6re d6couverte de poissons matins d6terminables dans le Permien des Pays Andins. Sa composition est en accord avec les ichthyofaunes du Permien inf6rieur marin des U.S.A. et d'Asie orientale.

KEY-WORDS : CHONDRICHTHYES, ACTINOPTERYGII, LOWER PERMIAN, NEW SPECIES, BOLIVIA, SOUTH AMERICA.

MOTS-CLt~S : CHONDRICHTHYES, ACTINOPTERYGII, PERMIEN INFI~RIEUR, NOUVELLE ESPI~CE, BOLIVIE, AMI~RIQUE DU SUD.

* Yacimientos Petroliferos Fiscales Bolivianos, appartado postal 401, La Paz, Bolivia. ** Institut de Pal6ontologie, 8 rue Buffon, 75230 Paris Cedex, France.

Geobios, n ° 19, fasc. 4 p. 479-493, 5 figs., 2 tabl., 1 pl. Lyon, aofit 1986

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1 - - I N T R O D U C T I O N

The material described herein was discovered in July 1984, by an expedition consisting of the authors, Dr. M. Suarez-Riglos (Y.P.F.B., Santa-Cruz, Boli- via) and Gabriela Rodrigo (Natural History Museum, La Paz, Bolivia).

Yaurichambi, which is situated along the La Paz- Tiquina highway, near Batallas (fig. 1A) is a famous locality in the early history of Geology, since A. d 'Orbigny visited it and collected there many Permian invertebrates described in his (~ Voyage dans l 'Am6ri- que m6ridionale >~ (d 'Orbigny 1842). Since that time, the Yaurichambi hill Jacha Khatawi has been the sub- j ect of thorough stratigraphical investigations, but the presence of fish remains in the Lower Permian Copa- cabana Formation, which crops out over most of this

hill, went unnoticed until now. This discovery repre- sents the first evidence of vertebrates in the marine Lower Permian of western South America, apart f rom the short mention of a ~( C l a d o d u s ~ tooth f rom the Copacabana Format ion at the Isla del Sol (Lake Titicaca, Bolivia; Janvier 1981, p. 24), and <~ fish teeth >> by Oviedo (1965).

The specimens described in this paper belong to the collection of the Centro de Tecnologia Petrolera of the Yacimientos Petroliferos Fiscales Bolivianos, Santa Cruz, Bolivia. Casts are available at the Institut de Pal6ontologie, Museum National d 'Histoire Natu- relle, Paris (8, rue Buff on, 75005 Paris, France).

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} Fish localit ies

Fig. 1 -- Locality map A, location of Yaurichambi in the Department of La Paz. B, Geological map of the Jacha Khatawi hill (from Sakagami & alii, 1984), showing the location of the section (a-b) in Figure 2.

Localisation du gisement A, emplacement de Yaurichambi dans le d6partement de La Paz. B, carte g6ologique de la colline de Jacha Khatawi (d'apr~s Saka- gami & alii, 1984), montrant la position de la section (a-b) dans la Figure 2.

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System

Permian

Formation

~-uncomform.----- Tiquina

C~ 0

%)

o -,-4 4~ .,-4

San Pablo

Collasuyo

Copacabana

Carboniferous-,-~-uncomform. s-~

Lithology

Sandstones

Calcareous plant horiz. lim=lites, marls and sandstones

Limestones, marls, lutites and limolites

Conglomerates, sandstones, lutites and predominantly limestones

Thickness

200 m

290 m

440 m

335 m

Fossils

Pecopteris hemileloides

Ostracods, bivalvs,algae

_brachiopods, palynomorphs

Brachiopods, bivalvs, gastropods, foraminifers, etc.

Table 1 -- General sequence of the Permian in the lake Titicaca area (from Calvo 1981).

S~quence g~n~rale du Permien dans la r~gion du Lac Titicaca (d'apr~s Calvo 1981).

Lithostratigraphy Conodont zones

?Neostreptognathodus 4 aff. sulcoplieatus

Sweetognathodus 0

"~ whitei

o o

Idiognathodus 2

ellisoni +I

0

Streptognathodus I elongatus

Localities

Yaurichambi M-6

Yaurichambi Ya 3 (M 3) Patapatani Torotoro (?)

Colquencha - Collana E1 Pelado Ho4951 E1 Tunal 11-2a- Encanada de Beu 1437 A

Yaurichambi Ya 2 (M I) iEI Pelado Ma4941

Age

Leonardian

Wolfcampian

Virgilian

Table 2 - - Conodont zones in the Copacabana Format ion (from Suarez-Riglos 1984). Zones de Conodontes dans la Formation de Copacabana (d'aprbs Suarez-Riglos 1984).

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2 -- GEOLOGICAL SETTING

Cabrera La Rosa & Petersen (1936) erected the name Copacabana Group for conglomerates sandstones, diamictites, limolites, lutites and limestones which crop out in the neighbourhood of Lake Titi- caca. Later, other authors, namely Newell, Chronic & Roberts (1953) have limited the Copacabana Group to the limestone series, and referred it to the Lower Per- mian.

Oviedo (1965) divided the group into two formations : below the Copacabana Formation, predominantly calcareous and, above, the Collasuyo Forma- tion, more sandy and limolitic. This author mentioned - but did not describe - minute fish teeth from a limestone bank in the latter formation.

Reyes (1972) changed the name Copacabana Group into Titicaca Group, following Chamot's (1965) sug- gestion. According to Calvo (1981), the Titicaca Group comprizes, from the base to the top, the following formations: Copacabana, Collasuyo, San Pablo and Tiquina. The Lowermost part of the Copa- cabana Formation may belong to the Upper Carboni- ferous, according to Reyes (1972), Urdininea (1975), Calvo (1981) and Suarez (1984). The general sequence for the Permian in the surroundings of Lake Titicaca is given in Table 1.

The Cerro Jacha Khatawi in Yaurichambi (Fig. 1) consists of two small hills. It displays three faults which are perpendicular to the orientation of the strata. The strike of the strata is N 452 W, and they dip 70°SW.

At the foot of the hills, there are outcrops of Devo- nian arenitic and pelitic rocks. They are overlain by reddish, strongly cross-bedded sandstones which are about 20 m thick and have been referred to the Gond- wana Series of the Carboniferous by Sakagami & alii (1984). The latter are unconformably overlain by the Copacabana Formation, which began to be deposited in the Upper Carboniferous, possibly in the Virgilian, and continued into the Lower Permian (Wolfcampian and Leonardian).

The Copacabana Formation consists mainly of calcareous sediments. It comprizes intercalations of limestones and marls, which show a marked dolomiti- zation and silicification to the top, which numerous chert banks in the upper part of the column (Fig. 2). The limestones are compact, whitish, greyish, purple and reddish and well exposed. They show traces of dissolution, calcite veins and cherts. The marls are whitish and foliated.

Above the Copacabana Formation undifferentiated Tertiary conglomerate lies unconformably and this consists of rounded sandstone pebbles in an argilo- arenaceous matrix (Calvo 1981; Sakagami & alii 1984).

The average profile is shown on the geological map published by Sakagami & alii (1984), along the section Yc (a-b, fig. 1 B).

The fauna of the Copacabana Formation in Yauri- chambi has been described on several occasions since d'Orbigny (1842). However, in spite of the numerous palaeontological investigations carried out on Jacha Khatawi over nearly a century and a half, no fish remain have previously been recorded from this locality. It has yielded brachiopods, fusulinids, bryozoans, trilobites, corals, conodonts, bivalves and crinoids. Among the more recent works on this locality, one may cite those by Dunbar & Newell (1946) and Arellano (1983) on trilobites, Samtleben (1971) on productid and spiriferid brachiopods, and Molina (1969) on fusulinids.

Urdininea & Yamagiwa (1980) have described the fusulinids from the Copacabana Formation in Yauri- chambi, and referred them to the Pseudoschwagerina zone, which is subdivided into three subzones : Eopa- rafusulina gracilis subz., Pseudoschwagerina texana subz., and Triticites cf. nitens subz.

Sakagami & alii (1984) studied mainly brachiopods, fusulinids and bryozoans, and referred the whole Copacabana Formation at Yaurichambi to the Wolf- campian.

In a recent work, Suarez-Riglos (1984) has defined a zonation of the Copacabana Formation on the basis of the conodonts and pointed out that the Virgilian, Wolfcampian and Leonardian were present in Yauri- chambi. He proposed the zones as indicated in Table 2.

Recent investigations show that zone 3 in Yauri- chambi contains the association of Sweetognathodus whitei and Neogondolella biselli, which is characteristic of the Upper Wolfcampian, and that zone 4 contains Neotreptognathodus pequopensis characteristic of the Lower Leonardian.

The fish remains described herein occur in the Eoparafusulina gracilis subzone of Urdiniera & Yamagiwa (1980), and in the conodont zone 4 of Suarez-Riglos (1984), with Neostreptognathodus pequopensis, the Lower Leonardian species which occurs in both fish horizons.

-- 483 --

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. . . . . . H y s t r i c u l i n a ? sp ~ ~ - N e o s p i r i f e r c a n d o r , C r u r ; [ h y r i s planoconvexa,Rhynchapora sp.

I ~ 1 ~ I - - t L i n o p r a d u c t u $ p a r v u s .

I I I I I

Fig. 2 - - Columnar section of the Copacabana Formation in Cerro Jacha Khatawi (a-b, fig. 1 B), from Sakagami & alii (1984), simplified, showing the position of the two fish horizons.

Colonne stratigraphique de la Formation de Copacabana sur la coiline de Jacha Khatawi (a-b, fig. 1 B), d'apr~s Sakagami & alii (19~4), simplifi~, montrant la position des deux horizons ~t poissons.

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3 - - DESCRIPTION

CHONDRICHTHYES

Most of the fish remains discovered at Yaurichambi belong to chondrichthyans, which are usually the most abundant forms in this facies of the Carbonife- rous and Permian all over the world. As mentioned above, many small-sized fish teeth and scales occur in the fish horizon 1 (fig. 2), and have been prepared by dissolution of the matrix with 10 °7o formic acid. By contrast, the large edestoid symphysial tooth series described below was found isolated in a thick calcareous red sandstone layer (fish horizon 2, fig. 2) and, thus, was difficult to prepare chemically, the teeth being poorly mineralized.

EUGENEDONTIDA ZANGERL, 1981

Edestoidea HAY, 1930

Agassizodontidae ZANGERL, 1981

REMARKS :

The Agassizodontidae are a group of often very large edestoids with considerably enlarged series of symphysial teeth. The characteristic of this group is the forward orientation of the lateral crown << wings >r of these teeth (lew., fig. 3 B3). The Agassizodontidae show a variety of forms, according to the develop- ment of the symphysial tooth series, ranging from short series (Sarcoprion, fig. 4 C ; Parahelicoprion, fig. 3) to very long series, forming complete spirals (Helicoprion, Fig. 4 D). The sister-group of the Agas- sizodontidae is the Edestidae (Zangerl, 1981, fig. 102).

Genus Parahelicoprion KARPINSKY, 1922

REMARKS :

Parahelicoprion belongs, with Sarcoprion, to the Agassizodontidae with a short symphysial tooth series (or arch), a characteristic which can be regarded as plesiomorphous, since it is the condition found in the Edestidae and Caseodontoidea. However, Paraheli- coprion differs from Sarcoprion in having much lon- ger lateral crown << wings >> of the symphysial teeth. The latter condition is probably apomorphous, since it occurs in the most derived Agassizodontidae, e.g. Campyloprion and Helicoprion. Campyloprion

is derived in having a very large number of slender symphysial teeth, and in Helicoprion, the latter form a very peculiar spiral (fig. 4 D). One may thus consi- der that Sarcoprion, Parahelicoprion, Campyloprion and Helicoprion show a morphocline with respect to the increase of the number of the teeth and the length of their lateral crowns. This morphocline is inconsis- tent with the cladogram proposed by Zangerl (1981, fig. 102) for the Agassizodontidae. However, it should be pointed out that the cladogram illustrated by Zangerl (1981, fig. 102) was not explained by him and it is therefore difficult to criticize.

Thus, there is no clear autapomorphy of Paraheli- coprion, which was hitherto monophyletic by monos- pecificity, but which may appear to be paraphyletic, since a new species is here provisionally included in it.

Parahelicoprion mariosuarezi nov. sp.

Fig. 3 A ; p l . 1 , fig. 1

DIAGNOSIS :

A large Parahelicoprion species with lateral crown wings of the symphysial teeth bearing only a few, slender denticles on their lingual end.

HOLOTYPE :

Specimen n ° 6097, Y.P.F.B. , Centro de Tecnologia Petrolera, Santa Cruz, Bolivia. (pl. 1 : 1). An isolated symphysial tooth series.

TYPE-LEVEL :

Red calcareous sandstone with traces of burrows (fish horizon 2) in the upper part of the Copacabana Formation, Lower Permian, Leonardian.

TYPE-LOCALITY :

Southwestern slope of the eastern part of the Jacha Khatawi hill, Yaurichambi, department of La Paz, Bolivia.

ORIGIN OF THE NAME "

Species named in honour of Dr. Mario Suarez- Riglos, Director of the Centro de Tecnologia Petro- lera, Y.P.F.B. Santa-Cruz, Bolivia.

- - 4 8 5 - -

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Fig. 3 -- A, Parahelicoprion mariosuarezi n.sp., Leonardian, Copa- cabana Formation, Yauri- chambi, Bolivia, Holotype (n ° 6097, Y.P.F.B., Santa- Cruz, Bolivia), symphysial tooth series in lateral view, the arrow points forwards. B, Parahelicoprion clerci (KAR- PINSKV), Lower Permian, Arta beds, Urals, U.R.S.S. ; Holotype in lateral view (B1), redrawn from Karpinsky (1916, fig. 1), and outline of the cast in the Krasnoufimsk museum (B2) figured by Bendix-Almgreen (1976, fig. 457 B) ; B3, reconstruction of the crown of one tooth in lateral view (from Karpinsky, 1922, fig. 3). Scale : 10 mm, the arrow points forwards. c.bl., cutting blade; I.c.w., lateral crown << wings >> ; psph.t, parasymphysial tooth; str., striae made by the upper tooth arch.

A, Parahelicoprion mariosuarezi n.sp., L6onardien, For- mation de Copacabana, Yau- richambi, Bolivie, Holotype (n ° 6097, Y.P.F.B., Santa- Cruz, Bolivie), s6rie de dents symphysaires inf4rieures en vue lat6rale, la flbche indique l'avant. B, Parahelieoprion clerei (KARP~NSKY), Permien inf6rieur, couches d'Arta, Oural, U.R.S.S. ; Holotype en rue lat6rale (B1), redessin6 d'apr6s Karpinsky (1916, fig. 1), et contour du moulage du Mus6e de Krasnoufimsk (B2), figur6 par Bendix-Almgreen (1976, fig. 457 B) ; reconstitution de la couronne d'une dent en vue lat6rale (d'aprbs Karpinsky, 1922 b, fig. 3). Echelle: 10 mm, la fl6che indique l'avant, c.bl., lame tranchante ; l.c.w., aile lat6- rale de la couronne ; psph.t, dent parasymphysaire ; str., stries d'usure dues aux dents sup6rieures.

REMARKS :

The genus Parahelicoprion (KARPINSKY 1922a, 1924) was hi therto represented by a single species, P. clerci (KARPINSKY) (<< Helicoprion >~ clerci, KAR- PINSKY, 1916, fig. 1-5). The latter is based on a poorly preserved symphysial tooth series. For u n k n o w n rea- sons, a cast of this holotype figured by Bendix- Almgreen (1976, fig. 457 B ; fig. 2 B2) appears more complete t han the specimen itself publ ished by Kar- p insky (1916, fig. l a ; fig. 2 B1). However, in bo th figures, it shows a remarkable similari ty with the holotype of P. mariosuarezi, in par t icular as to the

general shape and curvature of the teeth (fig. 3 A), with slender end gently curved lateral crowns. By contrast, P. clerci shows a wel l -marked serrat ion of the anter ior edge of the lateral crowns (fig. 3 B3), whereas only a few elongated and curved denticles occur on the anter ior end of the crown << wings >> in P. mariosuarezi (fig. 3 A, pl. 1 : 1 c). This difference is specifi- cally significant, and the lack of serrat ion in the latter species is p robab ly apomorphous , since the teeth are also clearly serrated in Sarcoprion (Nielsen 1952, pl. 6).

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Fig. 4 - - A,B, two old interpretations of the symphysial tooth series of Helico- prion : as attached to the snout (A) (from Karpinsky 1899) or to the tail (B) (from Simoens 1899, interpreta- tion rejected by this author). C, Sar- coprion edax NIELSEN, Upper Per- mian of Greenland ; reconstruction of the snout in lateral view (from Nielsen 1952). D, Helicoprion bessonowi KARPINSKY, Lower Permian, U.R.S.S. (from Zangerl 1981). E, Fadenia crenulata NIELSEN, Upper Permian, Greenland, reconstruction of the body (from Zangerl 1981). Scale • 100 mm. A,B, deux aneiennes interpretations des s6ries dentaires symphysaires de Helicoprion: fix6es sur le museau (A, d'apr6s Karpinsky 1899) ou sur la queue (B, d'apr6s Simoens 1899, interpr6tation toutefois rejet6e par cet auteur). C, Sarcoprion edax NInE- SEN, Permien sup6rieur du Groen- land; reconstruction du museau en vue lat~rale (d'apr~s Nielsen 1952). D, Helicoprion bessonowi KAR- PINSK¥, Permien inf6rieur d'U.R.S.S. (d'apr& Zangerl 1981). E, Fadenia crenulata NIELSEN, Permien sup& rieur du Groenland, reconstitution du corps (d'apr& Zangerl 1981). Echelle : 10 cm.

Parahelicoprion clerci occurs in the Lower Permian Arta beds of the Urals (U.S.S.R.), an age which is broadly similar with that of P. mariosuarezi.

DESCRIPTION "

The holotype of Parahelicoprion mariosuarezi is preserved in a relatively hard calcareous sandstone and has been partly prepared with 10 °7o formic acid. However, the preparation could not be continued, because of the fragility of the dentine of the specimen.

The tooth arch consists of nine teeth and may be regarded as almost complete. The foremost tooth (1, fig. 3 A) is very small and has a rounded lateral crown in lateral view. This unusual shape may be due to the resorption of the dentine. The following teeth (2-9, fig. 3 A) are relatively similar to each other, yet the length of the lateral crown increases in the rearmost teeth. The serrations of these crowns appear only in the teeth 3 to 9 (fig. 3 A).

The anterior tip of the lateral crown of the seventh tooth (7, fig. 3 A) is followed anteriorly by an elongated parasymphysial tooth on the left side (pspht. ; fig. 3 A, pl. 1 : lc). The latter extends ventrally to the sixth and fifth teeth and bears the same type of slender serrations as the lateral crowns of the symphysial teeth. Similar parasymphysial teeth, but somewhat

shorter, have been described in Sarcoprion edax (Niel- sen 1952, pl. 5, 6 ; fig. 4 C). Moreover, in the latter species, there is a much more marked difference in shape and size between the foremost and the rearmost teeth of the symphysial tooth series than in both P. clerci and P. mariosuarezi.

The cutting blade (e.bl., fig. 3 B3) of all the teeth is not preserved in the holotype of P. mariosuarezi (fig. 3 A, pl. 1 : 1), but one may reasonably infer that it was like in P. clerci (fig. 3 B). As in the latter species, the teeth of P. mariosuarezi show a lateral swelling near the limit between the cutting blade and the lateral crowns.

Some of the teeth show, on each side, vertical striae (str., fig. 3 A), which may be occlusion marks. The contact between the fourth and fifth teeth clearly shows that the base of the cutting blade of the fifth tooth passes slightly to the right side of the cutting edge of the fourth tooth (pl. 1 : lb), as in Campylo- prion ivanovi (KARPINSKY, 1922a, fig. 2 C). The rearmost teeth clearly show that their bases are fused to one another, as in Helicoprion (KARPINSKY 1899, fig. 37, 39). Finally, in dorsal view, the teeth appear slightly broader than those of P. clerci and, in this respect, more similar to those of Sarcoprion edax (NIEL- SEN, 1952, pl. 7).

-- 487 --

The position of the symphysial tooth series of Heli- coprion and of the Agassizodontidae in general have long been an enigma, and this problem raised fanciful interpretations. They have been interpreted as defense organs, placed either on the snout (fig. 4 A) or on the tail (fig. 4 B) of shark-like creatures (Karpinsky 1899, fig. 72). This question was answered by the discovery of an almost complete snout of Sarcoprion edax in the Upper Permian of Greenland (Nielsen 1952). It shows clearly that the massive tooth series were borne by the symphysial part of an elongated lower jaw (fig. 4 C), and were housed in a corresponding cavity of the upper jaw, when the mouth was closed. The occluding sets were two upper tooth rows in a parasymphysial position. The shape of the jaws bearing the large tooth spirals of Helicoprion are, however, still unk- nown.

The general shape of the body of the Agassizodonti- dae is not known, but one may speculate that it is quite similar to that of the closely related Caseodonti- dae, and particularly Fadenia crenulata NIELSEN (Zangerl 1981, fig. 95 F), that is, large shark-like fishes with an anteriorly placed dorsal fin, no pelvic and anal fins, and a pointed snout (fig. 4 E).

PETALODONTIDA ZANGERL, 1981

Pristodontidae WOODWARD, 1889

REMARKS :

The petalodontida is a group of poorly known chondrichthyans, mainly known by isolated teeth from the marine Carboniferous and Permian. They are characterize by linguo-labially compressed teeth, and the symphysial teeth often display the shape of a petal, hence the name of the group. The Pristodonti- dae is one of the most derived families of the Petalo- dontidae, since they possessed only one enlarged tooth on each jaw (Hansen 1978), thus forming a parrot-bill like jaw apparatus.

Genus Megactenopetalus DAVID, 1944

REMARKS :

Megactenopetalus is represented by two species, M. kaibabanus DAVID (1944) and M. shingkuoi YOUNG

(1950 ; Liu & Hsieh 1965), from the Permian of the U.S.A. and south China respectively. They are large forms, with obtusely curved teeth. This genus occurs also in the Upper Permian of Iran (Goldshani & Jan- vier 1974), with an undetermined species.

Megactenopetalus sp.

(Fig. 5 B ; pl. 1, fig. 2)

The broken tip of a presumed lower tooth is referred to an undetermined species of Megactenopetalus. The fine striation of its cutting edge, and the internal structure are quite similar to both species of this genus. However, the size and curvature of this specimen agree more with M. shingkuoi than with M. kaibabanus. The latter species is known only from the Lower Permian of the U.S.A. (Leonardian), whereas M. shingkuoi has been recorded from both the Lower Permian (Loping Series, Young 1950) and the Upper Permian (Yangsin Series, Liu & Hsieh 1965).

The general aspect of the Petalodontida was, until recently, known only from that of Janassa bituminosa (SCHAUMBERG, 1979), with a single complete specimen in ventral view. But recent discoveries from the Lower Carboniferous of Montana gave a more accurate knowledge of these fishes (Janvier &Lund 1985) : they are massive fishes, with very large pecto- ral and dorsal fins, and an almost diphycercal caudal fin (fig. 5 C). They were probably sluggish, benthic animals, feeding on brachiopods and crinoids, as evi- denced from the stomach content of J. bituminosa (MAHLZAHN, 1968).

? Bradyodonti gen. et sp. indet.

(pl. 1, fig. 3)

An isolated crushing tooth with a pitted surface due to tubular dentine may be questionably referred to an undetermined bradyodont. Its general shape, with a lateral hump of the occlusal surface is suggestive of the bradyodont tooth plates, in particular those of Lagarodus JAEKEL, from the Upper Carboniferous, and Helodus AGASSIZ, from the Carboniferous and Permian.

- - 4 8 8 - -

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Fig. 5 - - A, ~ Cladodus ~ sp., Leonar- dian, Copacabana Formation, Yaurichambi, Bolivia; fragmentary tooth in lingual view, n ° 6098, Y .P .F .B . , San ta -Cruz , Bolivia. B, Megactenopetalus sp., Leonardian, Copacabana Forma- t ion, Y a u r i c h a m b i , Bolivia ; symphysial tooth in lingual view, the outline of the whole tooth is based on M. kaibabanus DAVID, n ° 6099, Y.P.F.B. , Santa-Cruz, Bolivia. C, reconstruction of an unnamed Petalodontida from the Lower Carboniferous of Mon- tana, lateral view (from Janvier & Lurid 1985). Scale in ram.

A, ~ Cladodus ~ sp., L6onar- dien, Format ion de Copacabana, Yaurichambi, Bolivie ; dent frag- mentaire en rue linguale, n ° 6098, Y . P . F . B . , San t a -Cruz , Bolivie. B, Megactenopetalus sp., L6onardien, Format ion de Copa- cabana , Yaur ichambi , Bolivie dent symphysaire en vue linguale, le contour d 'ensemble de la dent est bas6 sur M. kaibabanus DAVID, n ° 6099, Y . P . F . B . , Santa-Cruz, Bolivie. C, reconstitution d'un P6talodontide non nomm6, du Carbonif~re inf6rieur du Montana (d'apr~s Janvier & Lund 1985). Echelle en ram.

E L A S M O B R A N C H I I

Form-genus ~¢ Cladodus ~ AGASSIZ

~ Cladodus ~ s p .

(Fig. 5 A ; pl. 1, fig. 5)

Several, relatively large teeth of ~ Cladodus ~ type have been found in the fish horizon 1. Their median cusp has lateral cutting edges, and their base shows a prominent lingual torus (l.t., fig. 5 A). These teeth are practically similar to those of Cladodus mirabilis AGASSIZ, the type species of the genus, from the Car- boniferous of Europe, but this type of tooth occurs in many other Palaeozoic chondrichthyan genera. It is probably plesiomorphous for the Elasmobranchii. Thus, Cladodus is considered as a nomen dub ium (Zangerl, 1981) and may only be used in a descriptive sense, as a (< form-genus 7>.

The << Cladodus ~ teeth from Yaurichambi have a strong median cusp, ornamented with sharp ridges running obliquely from the base to the tip of the cusp. The lingual torus seems to be single, as in Phoebodus , and more prominent than in most other (< Cladodus ~ species.

A C T I N O P T E R Y G I I

The fish horizon 1 has yielded some small-sized remains of actinopterygian fishes, mainly isolated rhombic scales and conical teeth with the typical transparent cap of acrodine. All these remains are undeterminable, except small hemisphaerical teeth (pl. 1 : 4), which are fairly common in the Lower and Middle Permian of North America and have been tentatively referred to the family Platysomidae (Johnson & Zidek 1981).

Family ? P l a t y s o m i d a e YOUNG

Since the 19th Century, the Permian of North Ame- rica has yielded small hemispherical ((( collar button- shaped >>) teeth, often attached on bony platelets which Estes (1969) named (( phyllodont >) tooth plates. The very thorough study of various phyllodont tooth plates led Johnson & Zidek (1981) to the conclu- sion that the Permian ones may be referred to platyso- mid actinopterygian fishes. The small tooth found in the fish horizon 1 (pl. 1 : 4) is similar to the teeth of a phyllodont tooth plate figured by these authors (Johnson & Zidek 1981, fig. 1 E) from the Lower Per- mian of Texas. Further investigations in Yaurichambi may reveal the presence of complete phyllodont tooth plates. Some large actinopterygian scales, associated with these teeth may also be referred to this group.

- - 489 - -

C O N C L U S I O N S

This fish assemblages f rom Y a u r i c h a m b i is in per- fect ag reemen t wi th the L e o n a r d i a n (Lower Pe rmian ) age suggested by the c o n o d o n t Neostreptognathodus pequopens&, it w o u l d be haza rdous to d raw large scale p a l a e o b i o g e o g r a p h i c a l conclus ions f r o m this f r a g m e n t a r y mater ia l , which shows aequa l ly close aff ini t ies wi th the Lower P e r m i a n fishes of N o r t h A m e r i c a and As ia , a pa t t e rn which should no t be sur- pr is ing, since mos t o f these fishes were pelagic fo rms (except pe ta lodon t ids ) .

By cont ras t , this fish f a u n a prov ides more useful da t a on the p a l a e o e n v i r o n m e n t o f the C o p a c a b a n a

F o r m a t i o n . The fish hor i zon 1, wi th pe t a lodon t ids , poss ib ly b r a d y o d o n t s and p l a t y s o m i d ac t inop te ry - gians is suggestive o f a shal low water and benth ic env i ronment . These d u r o p h a g o u s fishes p r o b a b l y fed on b ryozoans , mol luscs and cr inoids . The sharks and n o n - p l a t y s o m i d ac t inop te ryg ians were the only pelagic e lements o f this assemblage . The red sands tone o f the fish hor i zon 2 suggests a to ta l ly d i f fe ren t type o f env i ronment , poss ib ly a sandy in ter t ida l zone, on to which large pelagic fishes, such as Parahelicoprion, were eventual ly s t randed .

R E F E R E N C E S

AHFELD F. & BRANISA L. (1960) - Geologia de Bolivia. Inst. Boliviano Petrol., Ed. Don Bosco, La Paz, 245 p.

ARELLANO J. (1983) - Trilobites del Permico inferior de Bolivia. Bull. Inst. fr. Et. and., Lima, 12 (1-2), 91-102.

BENDIX-ALMGREEN S.E. (1976) - Paleovertebrate faunas od Greenland. In Geology of Greenland (A. Escher & W.S. Watt eds), 537-573, Geological Survey of Green- land, Copenhagen.

CABRERA LA ROSA A . & PETERSEN G. (1936) - Reconoci- miento geologico de los yacimientos petroliferos de1 Departamento de Puno. Bol. Cuerpo Ing. Minas Peru, Depto Petroleros, Limas, 115, 100 p.

CALVO J.C. (1981) - Estudio estratigraphico y sedimento- logico de las unidades litoestratigraphicas des Paleozoico Superior en el area comprendida entre las problaciones de Tiquina, Cumana y Yaurichambi (Depto La Paz). Unpublished Thesis, Univ. Mayor de San Andres, La Paz, 240 p.

CHAMOT G.A. (1965) - Permian section at Apillapampa, Bolivia, and its fossil content. J. Paleont., Tulsa, 39 (6), 1112-1124.

DAVID L.R. (1944) - A Permian shark from the Grand Canyon. J. Paleont., Tulsa, 18, 90-93.

DUMBAR C. & NEWELL N.D. (1946) - Marine early Per- mian of the Central Andes and its fusuline faunas. Amer. J. Sci., New Haven, 244 (6), 377-402; (7), 457-491.

ESTES R. (1969) - Studies on fossil phyllodont fishes: interrelationships and evolution in the Phyllodontidae (Albuloidei). Copeia, New-York, 2, 317-331.

GOLSHANI F. & JANVIER P. (1974) - Tooth fragment of a petalodontid fish (Elasmobranchii, Bradyodonti) from the Permian of Central Iran. Geol. Surv. Iran rep., Teheran, 31, 55-61.

HANSEN M.C. (1978) - A presumed lower dentition and a spine of a Permian petalodontiform chondrichthyan, Megactenopetalus kaibabanus. J. Paleont., Tulsa, 52 (1), 55-60.

JANVIER P. (1981) - On some fish remains from the Per- mian of North-Eastern Thailand. J. geol. Soc. Thailand, Bangkok, 4 (1-2), 23-28.

JANVIER P. & LUND R. (1985) - Ces 6tranges b~tes du Montana. La Recherche, Paris, 16, 98-100.

JOHNSON G.D. & ZIDEK J. (1981) - Late Paleozoic phyllodont tooth plates. J. Paleont., Tulsa, 55 (3), 524-536.

KARPINSKY A. (1899) - Ueber die reste von Edestiden und die neue Gattung Helicoprion. Werhandl. Kaiser. Russ. Miner. Ges., St. Petersbourg, 2d ser., 26 (2), 1-111.

KARPINSKY A. (1916) - On a new species of Helicoprion (H. clerci n.sp.). Bull. Acad. imp. Sci., St. Petersbourg, ser. 6, 6, 701-708. (in Russian).

KARPINSKY A. (1922a) - Helicoprion ivanovi n.sp., Bull. Acad. Sci. Russie, Moscou, ser. 6, 16 (1-18), 369-378 (in Russian).

KARPINSKY A. (1922b) - Remarques sur les s6ries dentaires des Edestidae et leur orientation. Bull. Acad. Sci. Russie, Moscou, 16 (1-18), 379-388. (in Russian).

- - 490 - -

KARPINSKY A. (1924) - Sur une nouvelle trouvaille de restes de Parahelicoprion et sur les relations de ce genre avec Campodus. Livre jubilaire Soc. gdol. Belg., Brus- sels, 1, 127-137.

LIU H.T. & HSIEH H.H. (1965) - The discovery of bradyodont from Yangsin Series, the Lower Permian of Liangs- han, Shensi. Vert. Palasiat., Peking, 9, 280-283. (in Chi- nese).

MALZAHN E. (1968) - Ueber neue Funde von Janassa bituminosa (SCHLOTHEIM) in niederrheinischen Zechstein. Ein Beitrag zur Histologie der Z~hne, Haut und Lebens- weise. Geol. Jb., 85, 67-96.

MOLINA C. (1969) - Estudio geologico de la peninsula de Cumana y contribucion al conocimiento de los foramini- feros permicos de Yaurichambi, Coquencha y Aplilla- pampa. UnpubL Thesis, Univ. Mayor San Andres, La Paz.

NEWELL N.D., CHRONIC J.G. & ROBERTS F.G. (1953) - Upper Paleozoic of Peru. GeoL Surv. Amer. Mem., Washington, 58, 276 p.

NIELSEN E. (1952) - On new or little known Edestidae from the Permian and Triassic of East Greenland. Meddr. Groenland, Copenhagen, 114 (5), 55 p.

ORBIGNY A. d' (1842) - Voyage dans l'Am6rique M6ridio- hale de 1826 ~ 1833, 3. Paldontologie. P. Bertrand, Paris, 248 p.

OVIEDO C. (1965) - Estratigrafia de la peninsula de Copa- cabana, Lago Titicaca, Departamento de La Paz. Bol. Inst. Boliv. Petrol., La Paz, 5 (1, 2), 5-15.

REYES F. (1972) - On the Carboniferous and Permian of Bolivia and Northwestern Argentina. Symp. Intern. Carb. Perm. Amer. Sul., Am. Ac. Brasil, Cienc., 4 (suppl.), 261-277.

SAKAGAMI S., YANAGIDA J., KAWABE T., KASE T., NAGAI K., SUGIYAMA T., R.ANGEL Z.C., ALDANA A.M., CARRASCO C.R, ) AGELLWNO L.G. (1984) -Biostratigraphic study of Paleozoic and Mesozoic groups in Central Andes : an interim report. Dept of Earth Sciences, Faculty of Sciences, Chiba University, 82 p., 7 fig., 29 pl.

SAMTLEBEN C. (1971) - Zur Kenntnis der Produktiden und Spiriferiden des bolivianischen Unterperms. Beih. geol. Jb, Hannover, III, 163 p.

SCHAUMBERG G. (1979) - Neue Kenntnisse fiber die Ana- tomie von Janassa bituminosa (SCHLOTHEIM) Holoce- phali, Chondrichthyes aus dem permischen Kupferschie- fer. Palgiont. Z., Stuttgart, 53 (3-4), 334-346.

SIMOENS G. (1899) - Note sur Helicoprion bessonowi (KARPINSKY). Bull. Soc. belg. G~ol. Pal~ont. Hydrol., Bruxelles, 13, 235-243.

SUAREZ-RIGLOS M. (1984) - Introduction a los conodontes des Permocarbonico de Bolivia. Mem. 3 ° Congresso Latinoamericano de Paleontologia, Mexico, 125-129.

URDININEA M. (1975) - Necessidad de un estudio biostra- tigraphico en el grupo Copacabana. Rev. Tee. Y.P.F.B., La Paz, 4 (3), 81-88.

URDININEA M. & YAMAGIWA N. (1980) - Paleontological study on the Copacabana Group at the hill of Jacha Kha- tawi in the Yaurichambi area, Bolivia, South America. Part 1 : Fusulinids. Professor Saburo Kanno Memorial Volume, Tokyo, 277-289.

YOUNG C.C. (1950) - Notes on the first occurrence of the order Bradyodonti in China. Sci. Record, Peking, 3, 243-246.

ZANGERL R. (1981) - Chondrichtyes 1, Paleozoic Elasmo- branchi. In Handbuch of Paleoichthyology (H.P. Schultze ed.), Gustav Fischer, Stuttgart, New York, 116 p.

Manuscr i t d6finit if regu le 03.02.1986

PLATE

P L A T E 1

Vertebrate remains from the Copacabana Formation, Lower Permian (Leonardian), Yaurichambi, Department of La Paz, Bolivia.

Restes de Vertebras de la Formation de Copacabana, Permien inf6rieur (L~onardien), Yaurichambi, D~partement de La Paz, Bolivie.

Fig. 1 - -

Fig. 2 -

Fig. 3 - -

Fig. 4 -

Fig. 5 -

Parahelicoprion mariosuarezi n. sp., lower symphysial tooth series, in lateral (a) and dorsal (b) view (x 0,5) and detail of the lateral crown wings (c, x 1). Holotype, n ° 6097, Y.P.F.B., Santa-Cruz, Bolivia.

S6rie de dents symphysaires inf6rieures, vue lat6rale (a) et dorsale (b), et d6tail de l'aile lat~rale des couronnes.

Megactenopetalus sp., fragmentary symphysial tooth in lingual view (x 2,5), n ° 6099, Y.P.F.B., Santa-Cruz.

Fragment de dent symphysaire en vue linguale.

? Bradyodonti gen. et sp. indet., crushing tooth in occlusal view (x 3). n ° 6101, Y.P.F.B., Santa-Cruz, Bolivia.

Dent broyeuse en vue occlusale.

Platysomidae gen. et sp. indet., isolated tooth from a phyllodont tooth plate, in lateral view (x 15). n ° 6100, Y.P.F.B. Santa-Cruz.

Platysomidae gen. et sp. indet, dent isol6e provenant d'une plaque dent6e de type phyUodonte.

~ Cladodus ~ sp., isolate monocuspid tooth (possibly a branchial arch denticle) (x 15), n ° 6102, Y.P.F., Santa-Cruz.

Dent monocuspide isol6e (peut-~tre un denticule branchial).

Geobios

n ° 19, fasc. 4 PI. 1

D. Merino-Rodo & Ph. Janvier

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Documents

Chondrichthyan and actinopterygian remains from theLower Permian Copacabana Formation of Bolivia