Bollettino della Società Paleontologica Italiana, 45 (1), 2006, 141-146. Modena, 30 settembre 2006141

First report of the genus Cladocyclus in the Lower of Pietraroja (Southern Italy)

Marco SIGNORE, Claudio PEDE, Enrico BUCCI & Carmela BARBERA

M. Signore, Dipartimento di Scienze della Terra, Università degli Studi di Napoli “Federico II”, Largo S. Marcellino 10, I-80138 Napoli, Italy; [email protected] C. Pede, Dipartimento di Scienze della Terra, Università degli Studi di Napoli “Federico II”, Largo S. Marcellino 10, I-80138 Napoli, Italy. E. Bucci, Istituto di Biostrutture e Bioimmagini del CNR, via Mezzocannone 16, I-80138 Napoli, Italy; [email protected] C. Barbera, Dipartimento di Scienze della Terra, Università degli Studi di Napoli “Federico II”, Largo S. Marcellino 10, I-80138 Napoli, Italy.

KEY WORDS - Lower Cretaceous, Ichthyodectidae, Pietraroja, Plattenkalk.

ABSTRACT - Among the ichthyofauna of Pietraroja, have been reported only from a post-cranial partial skeleton attributed to the Chirocentrites cf. coroninii, at the beginning of the 20th century. The recent discovery of a complete and articulated skull and pectoral girdle, which we attribute to Ichthyodectidae, confirms the fossil record of this family in the Lower Cretaceous of Southern Italy. Preliminary research on the cranial material suggest this specimen can be placed within the genus Cladocyclus. The preservation of the specimen is exceptional, as it is usual with fossils coming from the Pietraroja area. It preserves not only a fully articulated skull and pectoral girdle, but also soft tissue preservation of muscles around the ribs. This specimen is possibly the most complete ichthyodectid known from Southern Italy. Preliminary geochemical studies suggest that the specimen has been phosphatized, which may be a common process of fossilization in the Pietraroja area.

RIASSUNTO - [Prima segnalazione del genere Cladocyclus nel Cretaceo inferiore di Pietraroja (Italia meridionale)] - Il Plattenkalk di Pietraroja è noto fin dal 1798 per le sue peculiari condizioni di fossilizzazione, in particolare dell’ittiofauna. Tra i pesci fossili ritrovati a Pietraroja fino alla fine del XX secolo, gli Ichthyodectiformes erano rappresentati solamente da Chirocentrites cf. coroninii, descritto da un esemplare conservato presso il Museo di Paleontologia dell’Università di Napoli e mancante della parte anteriore del corpo. Tuttavia un recente ritrovamento della parte anteriore completa ed articolata di un ictiodectiforme ha espanso la distribuzione fossile di questo gruppo nel Cretaceo Inferiore del Sud Italia e probabilmente dell’intera Europa. Le prime analisi effettuate hanno attribuito questi resti al genere Cladocyclus, finora ristretto esclusivamente al Brasile (e probabilmente al Messico). La conservazione del reperto è eccezionale, come spesso accade per il giacimento di Pietraroja. Oltre a buona parte del cranio conservato ed articolato, è possibile osservare il cinto pettorale e la prima parte della colonna vertebrale in articolazione. Inoltre, sulle costole e sulle vertebre sono visibili porzioni di tessuti molli fosfatizzati. Il cranio è massiccio ed armato di lunghi denti, con una mandibola larga e profonda; la regione opercolare mostra distintamente i canali opercolari, ed i tessuti molli mostrano ad una prima osservazione al microscopio strutture che possono essere ricondotte alle fibre muscolari. Con ogni probabilità questo esemplare è l’ictiodectide meglio conservato dell’Italia meridionale, ed inoltre riveste una notevolissima importanza dal punto di vista paleogeografico, dal momento che si tratta dell’unica segnalazione del genere Cladocyclus in una zona diversa dal Sud America. Al momento attuale gli autori attribuiscono questo esemplare al “morph C” del genere Cladocyclus, ma sia la posizione geografica che alcune particolarità del cranio potrebbero far pensare di avere a che fare con una specie nuova del genere.

INTRODUCTION GEOLOGICAL SETTING

Ichthyodectiformes is a well known family of stem Pietraroja is a fossiliferous locality on the Matese group (Patterson & Rosen 1977) known from mountain, in Southern Italy, dated to the Early the Upper to the Upper Cretaceous worldwide. Cretaceous. The outcrop includes at least one Ichthyodectid morphology is conservative, allow for plattenkalk sequence, dated to the (Bravi, 1996; immediate identification of members of this group, Signore, 2001), which yields abundant fossil fishes. although the genus-level recognition is less clear. The geological setting of the area has been debated The genus Cladocyclus is hitherto known only from since the first descriptions of these outcrops. A the Cretaceous of Brazil, and while it is well known at complete review of the locality is beyond the scope of genus level, the species identification is still complex this short paper; for a summary see Bravi (1996), and unresolved (De Castro Leal & Brito, 2004). Here Signore (2001, 2004), Carannante et al. (in press). we report a fossil ichthyodectid from Pietraroja that In the last 40 years, the geological interpretation of can be attributed to the genus Cladocyclus. Pietraroja has changed considerably. The first attempt This discovery marks the first report of the genus at a geological analysis of the site was by D’Argenio from an European site, expanding the geographical (1963), and in the same year by Catenacci & Manfredini range of Cladocyclus. (1963). These authors agreed that Pietraroja was a very

ISSN 0375-7633 142 Bollettino della Società Paleontologica Italiana, 45 (1), 2006 shallow basin (possibly even a lagoon) subject to America), Leidy (Upper Cretaceous, periodical emersion, and subsequent oxygen depletion, worldwide), Cladocyclus Agassiz (Lower Cretaceous leading to starvation and mass-mortality events. In his of South America) and Chirocentrites Heckel (Upper analysis of the depositional environment Freels (1975) Cretaceous of Europe). favored the interpretation of Pietraroja as a starvation Ichthyodectoidei are characterized by usually large basin, quite similar to lagoonal deposits such as body size and a proportionally small head, elongated Solnhofen (Barthel et al., 1990). The only other body, dorsal and anal fins placed far posteriorly, and palaeoecological analysis of this site was performed well developed pectoral and caudal fins. by Bravi (1996), who agreed with the conclusions of The European record of the family Ichtyodectidae Freels (1975), but added new taphonomic observations. is poorly known, with two genera hitherto known from However, objections to these prevailing the Upper Cretaceous (Xiphactinus and Chirocentrites), interpretations were raised by Carannante (1982) who, and with Faugichthys Taverne & Chanet from the due to field observations of clearly preserved channel Lower Cretaceous. D’Erasmo (1914-15) identified an structures in the Miocene, inferred a similar depositional ichthyodectid fossil from Pietraroja as Chirocentrites environment for Pietraroja (see Carannante, 1982 for a coroninii, but this specimen is currently under revision complete description of the morphology and geology by the senior author. of the Miocene channel). Further sedimentological field studies and taphonomical analyses (Signore, 2001, 2004; THE PIETRAROJA SPECIMEN Carannante et al., in press) confirmed this idea. We follow the geological interpretation of Carannante et al. During a field trip in October 2004, one of the (in press): Pietraroja represents an obruption deposit, Authors (C.P.) found a piece of rock, containing part subject to slumps and microtorbidites. Carcasses were of a large fish, in a waste dump among rubbish and preserved due to the onset of preservative conditions discarded furniture. This specimen is articulated and into the sediments, even though the surrounding water there are indications of soft tissue preservation. was never lacking oxygen, as it is also confirmed by However, the posterior part of the body is missing. the preliminary geochemical analyses. The surface of the fossil is marked with several hammer blows, a possible sign of a failed attempt to steal the specimen. THE ICHTHYODECTOIDEI The specimen (Figs. 1-3) has been recovered and brought at the University of Napoli “Federico II”, The Ichthyodectoidei are a suborder of predatory Department of Earth Science, where it has been teleostean fishes within the stem group prepared and studied. The first report of the Ichthyodectiformes, known from the Upper Jurassic has been already published (Signore et al., 2005) and to Upper Cretaceous worldwide. It is represented by here we give the systematic interpretation of the animal. well known genera such as Hay (Upper However, a complete anatomical description is beyond Cretaceous of Western Interior Seaway of North the scope of this paper.

Fig. 1 - The specimen, in anatomical connection, showing the vertebral column and the almost complete skull. M. Signore, C. Pede, E. Bucci, C. Barbera - Cladocyclus in the Lower Cretaceous of Pietraroja 143

Fig. 2 - Close up of the skull of the specimen, showing oblique mouth, dentary, maxillary and premaxillary with teeth, and the strong jaws typical of the ichthyodectids.

The fossil lies on its right side, thus exposing its SYSTEMATIC PALAEONTOLOGY left side. While most of the skull and postcranium are visibile, the specimen bears some damage from hammer Subdivision TELEOSTEI Müller, 1846 strikes (Signore et al., 2005), which appear to be Stem group ICHTHYODECTIFORMES Bardak & Sprinkle, responsible for the loss of the ventral part of the lower 1969 jaw and ventral section of the preopercular and the Suborder ICHTHYODECTOIDEI Romer, 1966 opercular series (Fig. 2). Family CLADOCYCLIDAE Maisey, 1991 The specimen is well preserved, including the Genus Cladocyclus Agassiz, 1841 opercular canals (Fig. 3). Although the skull is crushed (Figs. 1-3) and some sutures are obscured by fractures, the skeleton is still in anatomical connection, and shows Diagnosis (after De Castro Leal & Brito, 2004) - no signs of postmortem disarticulation. Cladocyclid of large size; mouth oblique; premaxillary, The skull is typically ichthyodectid in both shape maxillary and dentary with teeth; large intercalar process and proportion, showing an oblique jaw opening, extending backwards, caudal fin endoskeleton with two elongated and deep dentary, large maxillary teeth, a large ural centra, eight hypurals, one epural and six premaxilla bearing small teeth, a large, subrectangular uroneurals; approximate vertebral count: 64. opercular, and a supraoccipital showing clear signs of Cladocyclus is hitherto known only from Brasil (see a crista, although damaged. Also, the specimen shows De Castro Leal & Brito, 2004 for a complete revision the proximal part of the pectoral fins, and at least the of the localities in which this genus is found). De Castro first 15 vertebrae, plus their ribs. Most of the postcranial Leal & Brito (2004) proposed the two known species specimen also shows extensive preservation of soft of the genus, C. ferus and C. gardneri, may represent tissues, which is currently under examination. different growth stages of the same animal. They also 144 Bollettino della Società Paleontologica Italiana, 45 (1), 2006

Fig. 3 - Close up of the opercular region, in which it is possible to see the tiny canals running on the opercular bone, perfectly preserved.

identified a third morph, that they called “morph C”, post mortem, but sank to the bottom almost with intermediate characteristics between C. ferus and immediately, and was covered by the sediment. Further C. gardneri. taphonomic analyses are still in progress, but preliminary observations show extensive soft tissues Description - Due to oblique mouth; premaxillary preserved in phosphates. The sampled soft tissue shows with small teeth, maxillary and dentary with large teeth; parallel lines at a distance of few micrometers, that deep and strong dentary; and a large and subrectangular have been tentatively interpreted as muscular tissue opercular (Cavin, pers. com.) (Fig. 2), the Pietraroja based on visible structure under the microscope and specimen is here tentatively attributed to the genus position on the specimen. However, there is no trace Cladocyclus, and we propose here that the specimen of scales, which are preserved in the other known discussed in this paper may belong to the “morph C” ichthyodectid from Pietraroja, Chirocentrites cf. sensu De Castro Leal & Brito (2004). We conclude that coroninii. this specimen does not belong to the only other known The specimen under study has interesting ichthyodectid taxon identified in Pietraroja palaeobiogeographical implications. The genus (Chirocentrites coroninii) due to the marked differences Cladocyclus is known only from the Lower Cretaceous in cranial structures and most of all due to the fact that of Brazil (and possibly from Mexico; Brito, pers. com). the genus Chirocentrites is edentulous. However we Therefore this is the first record of a Cladocyclus in also doubt the correct identification of D’Erasmo Europe. This may acquire additional significance in the (1914-15) specimen due to lack of the head in the latter light of the new discoveries in fish fauna from Pietraroja specimen. (De Vita, 2005) and it may mean that there was a faunal The specimen shows no signs of disarticulation (Fig. exchange between the South American coastal seas and 1), we therefore propose that the carcass did not float the southern Tethys during the Early Cretaceous. M. Signore, C. Pede, E. Bucci, C. Barbera - Cladocyclus in the Lower Cretaceous of Pietraroja 145

Cladocyclus is large and was probably a strong REFERENCES swimmer. Evidence suggests that it was even able to enter continental waters (either for reproduction or for Bravi S. (1996). Ricerche sui livelli ad ittioliti in facies di piattaforma carbonatica dell’Italia meridionale. Unpublished predation; Brito, pers. com.), therefore it is possible to doctoral thesis, University of Napoli “Federico II”. envisage a larger distribution for this genus than Carannante G., Vigorito M. & Signore M. (in press). Vertebrates- previously thought. Fossil rich plattenkalk of Pietraroia (Southern Apennines, Italy). New environmental and sedimentological considerations. Facies. CONCLUSIONS Carannante G. (1982). La valle del Canale (Civita di Pietraroja, Matese). Una incisione Miocenica riesumata sul margine della piattaforma carbonatica Abruzzese - Campana. Geologica The specimen found in Pietraroja is here attributed Romana, 21: 511-521. to the genus Cladocyclus. However, further Catenacci E. & Manfredini M. (1963). Osservazioni observations may even indicate that this is a new species stratigrafiche sulla civita di Pietraroja (Benevento). Bollettino (this evidence would be eventually corroborated by the della Società Geologica Italiana, 82: 65-92. different geographical distribution of the genus). D’Argenio B. (1963). I calcari ad ittioliti del Cretacico inferiore As this is the first report of the genus Cladocyclus del Matese. Atti dell’Accademia Scienze Fisiche e Matematiche, 4: 5-63. outside South America, the presence of a faunal element De Castro Leal M.E. & Brito P. (2004). The ichthyodectiform from a different paleobiogeographical area may even Cladocyclus gardneri from the Crato and Santana Formations, indicate that the Pietraroja specimen is a new species Lower Cretaceus of , North-Eastern Brazil. of the genus Cladocyclus. In any case, this discovery Annales de Paléontologie, 90: 103-113. is important as it widens the geographical distribution D’Erasmo G. (1914-15). La fauna e l’età dei calcari ad ittioliti di of the genus Cladocyclus and it represents the first Pietraroja (Benevento). Palaeontographia Italica, 20: 29- 96; 21: 21-59. report of this South American Cretaceous fish in De Vita S. (2005). Nuovi esemplari di Aspidorhynchidae nel Europe. Cretaceo Inferiore di Pietraroja. Unpublished bachelor thesis, The high percentage of soft tissue preserved University of Napoli “Federico II”. confirms the great taphonomical capability of the Freels D. (1975). Plattenkalke becken bei Pietraroja (Prov. Pietraroja outcrop, will allow for further researches Benevento, Sud Italien) als Vorussetzug einer fossil-lagerstätte into phosphatization of soft tissue in the site, and also erbildung. Neues Jahrbuch für Geologie und Paläontologie Abteilung, 148: 320-352. allows a better understanding of the subdermal Patterson C. & Rosen D.E. (1977). Review of ichthyodectiform muscular structure in ichthyodectids. and other Mesozoic fishes and the theory and practice Furthermore, in the light of the new findings, it looks of classifying fossils. Bulletin of the American Museum of like Pietraroja has been investigated only on the surface, Natural History, 158: 81-172. and many things are about to change both in the Signore M. (2001). Scipionyx samniticus and the paleobiology palaeoenvironmental interpretation, and in the faunistical of some maniraptoran theropods. Unpublished PhD thesis, assemblage. University of Bristol, UK. Signore M. (2004). Sample excavations in Pietraroja (lower Cretaceous, Southern Italy) in 2001 and notes on the Pietraroja palaeoenvironment. PalArch, 2: 14-22. ACKNOWLEDGEMENTS Signore M., Bucci E.M., Pede C. & Barbera C. (2005). A new ichthyodectid fish from the Lower Cretaceous of Pietraroja We thank prof. Lucia Simone and Gabriele Carannante (Southern Italy). PalArch, 5: 25-29. (University of Napoli, Italy) who kindly supported us both in Taverne L. & Chanet B. (2000). Faugichthys loryi n. Gen., sp. the field during the collection of the specimen and with some (Teleostei, Ichthyodectiformes) de l’Albien terminal (Crétacé invaluable suggestions for the sedimentology of the area. We inférieur marin) du vallon de la Fauge (Isère, France) et also would like to thank prof. Paulo Brito (Universidade do considérations sur la phylogénie des Ichthyodectidae. Estado do Rio de Janeiro, Brazil) dr. Lionel Cavin (Musée des Geodiversitas, 22 (1): 23-34. Dinosaures, Esperaza, France) and dr. Matt Friedman (University of Chicago, USA) for discussions, opinions, and great help. Special thanks to dr. Pellegrino Covino for help with fossil preparation and handling, and Stelio Grombone (University of Manuscript received 02 December 2005 Napoli, Italy) for help with specimen preparation and storage. Revised manuscript accepted 30 June 2006 146 Bollettino della Società Paleontologica Italiana, 45 (1), 2006