Mesozoic Fishes 3 – Systematics, Paleoenvironments and Biodiversity

Preface 7
Acknowledgements 7
Barbara J. STAHL:
The structure of the early chimaeroid dentition 11
John G. MAISEY, Gavin J. P. NAYLOR & David J. WARD:
Mesozoic elasmobranchs, neoselachian phylogeny and the rise of modern elasmobranch diversity 17
Jürgen KRIWET:
The systematic position of the Cretaceous sclerorhynchid sawfishes (Elasmobranchii, Pristiorajea) 57
Marcelo R. de CARVALHO:
A Late Cretaceous thornback ray from southern Italy, with a phylogenetic reappraisal of the Platyrhinidae (Chondrichthyes: Batoidea) 75
Paulo M. BRITO & Didier B. DUTHEIL:
A preliminary systematic analysis of Cretaceous guitarfishes from Lebanon 101
Charlie J. UNDERWOOD & David J. WARD:
Environmental distribution of Bathonian (Middle Jurassic) neoselachians in southern England 111
Lance GRANDE:
Categorizing various classes of morphological variation, and the importance of this to vertebrate paleontology 123
Norbert MICKLICH & Gottfried KLAPPERT:
Character variation in some Messel fishes 137
Cecile POPLIN:
The dermosphenotic in early actinopterygians, a nomenclatural problem 165
Cristina LOMBARDO & Andrea TINTORI:
New perleidiforms from the Triassic of the Southern Alps and the revision of Serrolepis from the Triassic of Württemberg (Germany) 179
Raoul MUTTER:
The "perleidiform" family Colobodontidae: A review 197
Eric J. HILTON, Lance GRANDE & William E. BEMIS:
Morphology of †Coccolepis bucklandi AGASSIZ, 1843 (Actinopterygii, †Coccolepidae) from the Solnhofen Lithographic Limestone deposits (Upper Jurassic, Germany) 209
Toni BÜRGIN:
†Eosemionotus ceresiensis sp. nov., a new semionotiform fish (Actinopterygii, Halecostomi) from the Middle Triassic Monte San Giorgio (Southern Switzerland) 239
Valéria GALLO & Paulo M. BRITO:
An overview of Brazilean semionotids 253
Katia GONZÁLEZ-RODRÍGUEZ & Victor-Hugo REYNOSO:
A new Notagogus (Macrosemiidae, Halecostomi) species from the Albian Tlayúa Quarry, Central Mexico 265
Gloria ARRATIA:
Mesozoic halecostomes and the early radiation of teleosts 279
J. Ralph NURSALL & Luigi CAPASSO:
Gebrayelichthys (novum), an extraordinary genus of neopterygian fishes from the Cenomanian of Libanon 317
Francisco J. POYATO-ARIZA & Sylvie WENZ:
The new pycnodontid fish genus Turbomesodon, and a revision of Macromesodon based on new material from the Lower Cretaceous of Las Hoyas, Cuenca, Spain 341
Jeff LISTON:
An overview of the pachycormiform Leedsichthys 390
René ZARAGÜETA BAGILS:
Basal clupeomorphs and ellimmichthyiform phylogeny 391
Peter L. FOREY:
A three-dimensional skull of a primitive clupeomorph from the Cenomanian English Chalk, and implications for the evolution of the clupeomorph acusticolateralis system 405
Terry GRANDE & Mario de PINNA:
The evolution of the Weberian apparatus: A phylogenetic perspective 429
Chelsea R. HERMUS, Mark V. H. WILSON & Andrew MACRAE:
A new species of the Cretaceous teleostean fish Erichalcis from Arctic Canada, with a revised diagnosis of the genus 449
Hans-Peter SCHULTZE:
Mesozoic sarcopterygians 463
Lionel CAVIN & Peter L. FOREY:
New mawsoniid coelacanth (Sarcopterygii: Actinistia) remains from the Cretaceous of the Kem Kem beds, Southern Morocco 493
Niels BONDE:
An Early Cretaceous (Ryazanian) fauna of "Purbeck-Wealden type" at Robbedale, Bornholm, Denmark 507
Valentina KARATAJUTE-TALIMAA & Valentas KATINAS:
Occurrence of Triassic fishes in the East Baltic Region 529
Mee-mann CHANG & Desui MIAO:
An overview of Mesozoic Fishes in Asia 535
Haruka YAMAGISHI:
Elasmobranch remains from the Taho Limestone (Lower-Middle Triassic) of Ehime Prefecture, Southwest Japan 565
Mark V. H. WILSON & John C. BRUNER:
Mesozoic fish assemblages of North America 575
Adriana LÓPEZ-ARBARELLO:
The record of Mesozoic fishes from Gondwana (excluding India and Madagascar) 597
Guntupalli V. R. PRASAD, Brijesh K. MANHAS & Gloria ARRATIA:
Elasmobranch and actinopterygian remains from the Jurassic and Cretaceous of India 625
David BELLWOOD & Andrew HOEY:
Feeding in Mesozoic fishes: a functional perspective 639

Barbara J. STAHL†: The structure of the early chimaeroid dentition
[pp. 11-16, 4 figs.]

The discovery, early in the chimaeroid fossil record, of palatine tooth plates of a distinctive structure once referred to the genus Ganodus and now recognized as part of the dentition of Elasmodectes has raised the possibility that the elasmodectid chimaeroids may be ancestral to the diverse groups of chimaeroids that flourished in later Jurassic and Cretaceous time. Although this hypothesis is not consonant with the assumption that the callorhynchids with tooth plates bearing massive tritors are the most primitive chimaeroids, it cannot be dismissed as untenable. Until additional fossil evidence clarifies the origin and diversification of the chimaeroids, that the first chimaeroids had less robust tooth plates armed with tritoral rods rather than large pads should be considered a possibility.

John G. MAISEY, Gavin J. P. NAYLOR & David J. WARD: Mesozoic elasmobranchs, neoselachian phylogeny and the rise of modern elasmobranch diversity
[pp. 17-56, 16 figs., 2 tabs., 1 app.]

In terms of diversity and abundance, the two most important groups of Mesozoic elasmobranch fishes are hybodonts and neoselachians (the latter including all the modern sharks and rays). Both groups are probably monophyletic, and hybodonts appear to be the closest extinct sister group to neoselachians. Much of the modern elasmobranch diversity arose in the Mesozoic, and the fossil record suggests that extinction was an important factor in early neoselachian history. The relationships of Mesozoic neoselachians are best investigated within a phylogenetic framework of extant forms. Unfortunately there are significant discrepancies between phylogenetic analyses of modern elasmobranchs founded upon morphological and molecular data. Recently-published morphological trees place the batoids in a terminal position, nested high within squalean sharks. Molecular data from RAG-1 (a nuclear gene) and ND2 (a mitochondrial gene) support an opposite conclusion, in which batoids occupy a basal position as the sister group to modern sharks. Stratigraphic data (heavily biased toward isolated teeth) are highly congruent with the molecular tree, suggesting that the neoselachian fossil record contains only a few gaps of relatively short duration. By contrast the morphological trees predict that numerous lengthy gaps exist in the fossil record of many modern elasmobranch lineages, and that a major radiation of numerous modern elasmobranch lineages occurred prior to the early Jurassic. This is of general interest, because in other phylogenetic studies molecular data have frequently implied greater antiquity than morphological evidence (e.g., mammals, birds). Our findings clearly demonstrate that estimates of taxon longevity are critically dependent on the phylogeny used, and also show how the fossil record may be useful as an arbiter between competing phylogenetic hypotheses.

Jürgen KRIWET: The systematic position of the Cretaceous sclerorhynchid sawfishes (Elasmobranchii, Pristiorajea)
[pp. 57-73, 7 figs., 3 apps.]

Articulated and isolated material of fossil sclerorhynchid sawfishes is re-evaluated to present a hypothesis of the phylogenetic relationships of †Sclerorhynchidae within batoids using cladistic principles. †Sclerorhynchidae is a monophyletic group of fossil batoid fishes, which are restricted to the Cretaceous. A phylogenetic analysis, including the fossil sclerorhynchids and †Iansan from the Lower Cretaceous of Brazil is presented. According to this analysis, a monophyletic clade Pristiorajea is confirmed with pristiophoriforms being the most basal batoid clade. †Sclerorhynchidae represents the sister group to pristiforms and all remaining pristiorajeans. Consequently, a new order, †Sclerorhynchiformes, is introduced. A hypertrophied rostral cartilage with lateral rostral spines was developed independently within several closely related clades according to the present hypotheses. The systematic position of †Iansan within pristiorajeans remains unresolved.

Marcelo R. de CARVALHO: A Late Cretaceous thornback ray from southern Italy, with a phylogenetic reappraisal of the Platyrhinidae (Chondrichthyes: Batoidea)
[pp. 75-100, 12 figs., 1 app.]

A new genus and species of fossil thornback ray (Platyrhinidae) is described from the Campanian/Maastrichtian "Calcare di Melissano" Formation of Nardò, in the southern Italian province of Puglia. †Tethybatis selachoides, gen. et sp. nov., known from two specimens preserved in part and counter-part, is a large batoid with a relatively complete disc extending anterior to the neurocranium (supported internally by propterygia and radials), a stout shark-like tail with large dorsal and caudal fins, and a dense coating of very small and compacted dermal denticles. The holotype is an adult male exposed in dorso-ventral view, with large regions of the disc, pelvic fins, and part of the tail present; the paratype is laterally exposed and represents only the tail with dorsal and caudal fins. Many anatomical features are preserved, revealing aspects of the braincase, pectoral disc, visceral skeleton, shoulder and pelvic girdles, pelvic fins, clasper, dorsal and caudal fins and dermal skeleton. Soft-tissue (skin patches) is also preserved over much of the disc and fins. Comparisons with other groups of batoids, both fossil and living, reveal that the new form is unique in having a very elongated propterygium, reaching anterior to the braincase, and composed of a single element. The Nardò batoid is further distinguished from living thornbacks by lacking enlarged thorns, and by presenting a prominent space separating the hyomandibulae and lower jaws (indicating, possibly, a larger spiracular opening). The Platyrhinidae is redefined and its intrarelationships are discussed. †Tethybatis is assigned to the the family on the basis of presenting its apomorphic rostral morphology, is its most basal member, and is the first Mesozoic record of the family corroborated by shared derived characters. The Nardò deposits are the only fossil beds from the Campanian/Maastrichtian of European Tethys represented by complete fishes, and †Tethybatis is the only fossil batoid known from articulated remains from the latest Cretaceous.

Paulo M. BRITO & Didier B. DUTHEIL: A preliminary systematic analysis of Cretaceous guitarfishes from Lebanon
[pp. 101-109, 3 figs., 1 app.]

The Late Cretaceous Lebanese guitarfishes, previously described from the Cenomanian-age localities of Haqil and Hgula, and the Santonian Sahel Alma, are re-examined cladistically. A phylogenetic analysis considering 28 characters and 21 terminal taxa, including fossil species (e.g., †Rhinobatos maronita, †R. hakelensis, †R. whitfieldi, †R. tenuirostris, †R. intermedius, †R. latus, †R. primarmatus, and †Rhombopterygia rajoides) and 13 extant taxa, corroborates the polyphyletic condition of the genus Rhinobatos. †Rhinobatos maronita and †R. tenuirostris are here suggested as forming a clade with the extant Rhynchobatus species. The more advanced guitarfishes plus the rajids are rooted as the sister group of the torpediniforms, forming a clade largely unresolved. Our results suggest that a thorough revision of the Cretaceous guitarfishes is required.

Charlie J. UNDERWOOD & David J. WARD: Environmental distribution of Bathonian (Middle Jurassic) neoselachians in southern England
[pp. 111-122, 5 figs., 1 app.]

Within the Bathonian (Middle Jurassic) a wide range of depositional environments were present across Britain. Within this dominantly carbonate shelf setting, there is a general palaeoenvironmental transition from open marine shelf in the south of England, to marine and non-marine lagoons in south-central England. Isolated teeth of neoselachians are frequent at several localities within a range of marine and lagoonal facies. Extensive bulk sampling has allowed teeth from over 20 neoselachian taxa to be recovered from several distinct facies. The distributions of many species suggest that they were strongly environmentally controlled, with few taxa being commonly present within both open marine and lagoonal settings. Some taxonomic groups appear to have been restricted to specific environments, with hexanchids and palaeospinacids only being recorded within open marine facies. Within other groups, environmental segregation is at generic and specific level, with different species of Protospinax, orectolobids, batoids and scyliorhinids being recorded within different facies. The differential distribution of neoselachians within the Bathonian demonstrates that the initial phase of neoselachian radiation during the late Early and Middle Jurassic was accompanied by diversification into a wide range of ecological niches. This greatly increases our understanding of the mechanisms and timing of neoselachian radiation and Jurassic fish palaeoecology.

Lance GRANDE: Categorizing various classes of morphological variation, and the importance of this to vertebrate paleontology
[pp. 123-136, 8 figs.]

For paleontologists, as well as other anatomists, the concept of morphological variation is crucial and lays the foundation on which almost all of our scientific work rests. It is useful to subdivide and categorize different types of morphological variation to more fully understand the concept.

Morphological variation is a complex mix of interspecific and intraspecific variation. One way we can subdivide the concept of morphological variation is in terms of empirical continuity. Continuous variation is something that we sometimes directly observe as a process during ontogeny, but in most cases it is an extrapolation made by connecting ordered discrete components. Discontinuous variation is recognized by empirical gaps in morphological continuity. It is discontinuous variation that enables us to recognize different species morphologically, which in turn allows us to recognize different higher taxa.

Another way we can subdivide the concept of morphological variation is to sort it into three main types: taxonomic, ontogenetic, and individual. Taxonomic variation includes the morphological differences between taxa (e.g., proper differential diagnoses). Ontogenetic variation comprises the differences between growth stages of an individual organism (usually extrapolated from size correlated differences observed in a population or a species). Individual variation occurs within an individual (i.e. between right and left sides or among serially homologous structures), or between different individuals of the same terminal taxon (species or subspecies). In this paper, I will focus on the latter type, which I define as differences between similar sized individuals of the same species (including typical polymorphisms, sexual dimorphism, and anomalies). This paper gives examples of these types of morphological variation and reviews why it is particularly important to remember the distinctions between them.

Norbert MICKLICH & Gottfried KLAPPERT: Character variation in some Messel fishes
[pp. 137-163, 14 figs.]

Comparative investigations into the morphology of Thaumaturus intermedius WEITZEL, 1933 and Atractosteus strausi (KINKELIN, 1884) from the Messel Formation (Middle-Eocene) reveal a high degree of variation within both nominal species, which is examplified by different skeletal details. This variation exceeds that reported from contemporaneous fossils as well as the variation reported from related extant species. It cannot be explained by "regular" intraspecific variation (inclusive rare phenotypes), artefacts of fossilisation, or preservation and preparation; nor is it a result of time averaged sampling. For the gars, some specimens share outstanding morphological peculiarities and, therefore, were delimitated from all other Atractosteus as a new genus and species (MICKLICH & KLAPPERT 2001). All of the other specimens within both nominal taxa are interpreted as morphotype complexes. They may represent sibling species or perhaps foreshadow future speciation events. Basing on different hypotheses concerning the genesis of the Messel Lake, scenarios are discussed which may explain the observed variation. In contrast to the results of drilling projects, which demonstrate that ancient Messel Lake originated in a maar and remained isolated for a long period of time, some different developmental stage in the history of this lake seems to be represented by the specimens described here. At the time these specimens were alive, Messel Lake probably was part of a drainage system, at least for restricted periods of time. Such an interpretation is in good correspondence with peculiarities concerning the general composition of the fish fauna, growth characteristics and length-frequency distributions of the different species, the morphological variation in other fishes from Messel Lake, as well as the stratigraphic positions of the oil shale sections, from which came most of the materials described in this paper.

Cécile POPLIN: The dermosphenotic in early actinopterygians, a nomenclatural problem
[pp. 165-178, 7 figs., 1 tab.]

The dermosphenotic, dermal bone situated postero-dorsally to the orbit, was first defined in recent actinopterygians after anatomy (braincase and sensory canals), development, and innervation of neuromasts. The last two criteria are unusable in fossil groups without recent representatives, and recognition of the dermosphenotic after anatomical features proves often difficult because of many variations, also because some paleontologists try to apply the homologization principle of sarcopterygian bone nomenclature to actinopterygians. This resulted in a quantity of different names, more or less complicated, given to the bones lying in this region, and therefore to misunderstandings. A topographic definition of this bone is proposed, based on simple landmarks, in order to solve this problem and allow scientists to speak the same language. Its test within a small sampling (83 genera, 13 species) of mainly fossil taxa (basal Actinopterygii up to crown Neopterygii) reveals the existence of two main patterns in this region of the skull, which can be subdivided for mere practical reasons. It appears that groupings of taxa according to these patterns are often coherent with high levels of systematics. Consequently these new definition and nomenclature of the dermosphenotic suggest homologies and they are proposed here as tools for the search of phylogenetic relationships of actinopterygians, mostly early ones.

Cristina LOMBARDO & Andrea TINTORI: New perleidiforms from the Triassic of the Southern Alps and the revision of Serrolepis from the Triassic of Württemberg (Germany)
[pp. 179-196, 11 figs.]

A new actinopterygian genus, Felberia gen. nov., is described on the basis of a few, well-preserved specimens from the Ladinian Kalkschieferzone of Meride (Canton Ticino, Switzerland), and of some fragmentary remains from the Carnian localities of Oltre il Colle (BG) and Raibl-Cave del Predil (UD). The new genus, belonging to Perleidiformes, is characterized by a deep body covered with narrow and high, strongly ornamented, but thin scales. The head is deep as well. It shows a preoperculum with equal-sized dorsal and ventral regions, an operculum larger than the suboperculum, and a small gape with teeth that are long, pencil-like and protruding on the oral margin, and stout and acuminate on the palatal bones. The fins are long and delicate. Dorsal and anal fins are located close to the tail, which is characterized by seven epaxial rays and a ventral lobe slightly larger than the dorsal. The morphology of the new genus, with its deep, laterally compressed body and its peculiar dentition, suggests a specialized feeding habit, such as preying on small crustaceans on a rough bottom: the prey could have been seized with the marginal protruding teeth and then crushed by the strong palatal ones.

The systematic position of the genus Serrolepis QUENSTEDT from the Lettenkohle of Württemberg, is also discussed, based on comparisons of part of the original material with these new well-preserved specimens. Due to the morphology of both scales and palatal teeth, Serrolepis is moved from the order Semionotiformes to the order Perleidiformes.

Raoul J. MUTTER: The "perleidiform" family Colobodontidae: A review
[pp. 197-208, 5 figs., 1 app.]

Critical review of research history of the Colobodontidae reveals that the affinities of the type species Colobodus hogardi are unknown, the type material is not recoverable, and that the validity of the name Crenilepis DAMES, 1888 is equivocal. Furthermore, the family Perleididae BROUGH, 1931 and the probably paraphyletic 'Perleidusgroup' GARDINER & SCHAEFFER, 1989 have been implicitly regarded a synonym of the unsatisfactorily defined family Colobodontidae, including various sets of taxa. At present, the Colobodontidae sensu ANDERSSON (1916) comprises at least 3 genera with 7 species whose diagnoses are revised: Colobodus AGASSIZ, 1844, Crenilepis DAMES, 1888 and a new genus. The taxonomic status of poorly preserved species of Colobodus is reviewed and assessed.

Eric J. HILTON, Lance GRANDE & William E. BEMIS: Morphology of †Coccolepis bucklandi AGASSIZ, 1843 (Actinopterygii, †Coccolepidae) from the Solnhofen Lithographic Limestone deposits (Upper Jurassic, Germany)
[pp. 209-238, 14 figs., 6 tabs.]

The morphology of †Coccolepis bucklandi is described based on newly prepared specimens. †Coccolepis is a genus of small basal (i.e., non-neopterygian) actinopterygian fishes, historically included in the assemblage †"Palaeonisciformes." †Coccolepis bucklandi is one of the rarest taxa from Solnhofen, and its morphology is virtually unknown. One of the most striking aspects of this taxon is the presence of thorn-like denticles that cover the entire external surface of the dermal skeleton (e.g., dermal skull bones, scales, fin fulcra, and fin rays). The scales of †Coccolepis also are unusual (although not unique) among basal actinopterygians in being thin and overlapping. †Coccolepis bears an enlarged pectoral fin spine that is formed in part by fused fringing fulcra. The heterocercal caudal fin of †Coccolepis is very much like that of most other basal actinopterygian fishes in that the upper lobe is covered laterally with a field of rhombic caudal scales and the upper and lower lobes have basal fulcra. The lateral line continues posteriorly onto the upper lobe of the caudal fin in a series of tubular ossicles ventral to the field of rhombic caudal scales, similar to the condition of some members of Chondrostei (sensu GRANDE & BEMIS 1996).

Toni BÜRGIN: †Eosemionotus ceresiensis sp. nov., a new semionotiform fish (Actinopterygii, Halecostomi) from the Middle Triassic of Monte San Giorgio (Southern Switzerland)
[pp. 239-251, 10 figs.]

Of the approximately 40 actinopterygian taxa presently known from the Middle Triassic of Monte San Giorgio (Southern Switzerland), the semionotiform genus †Eosemionotus STOLLEY, 1920 is represented by at least five distinct morphotypes. One of these, †Eosemionotus ceresiensis sp. nov., differs from all the others by its body shape, meristic data and details of the fin structures. The specimens are less than 60 mm in total length and are found in the "Grenzbitumenzone" (Anisian-Ladinian boundary) and in the slightly younger lower Meride Limestone (Early Ladinian). A special feature of †Eosemionotus is its peculiar dentition, which consists of a series of elongate, forwardly pointing, pencil-like teeth on both the premaxilla and dentary. This type of feeding apparatus would be effective for picking and tearing small invertebrates from the substratum.

†Eosemionotus is recorded from Middle Triassic marine deposits in Switzerland, Italy, Germany, the Netherlands and Spain, marking the widespread distribution of this actinopterygian taxon in the Western Paleo-Tethyan realm.

Valéria GALLO & Paulo M. BRITO: An overview of Brazilian semionotids
[pp. 253-264, 10 figs., 1 app.]

The family Semionotidae is a diverse group of Mesozoic neopterygians, very common also in Western Gondwanian strata, ranging from Late Jurassic to Late Cretaceous. In Brazil, it is represented by forms like the large, higher ossified, and with crushing dentition Lepidotes spp. from the Recôncavo Basin; and the small filter feeders such as Araripelepidotes from the Araripe Basin. This family exhibits an enormous diversity of forms and habits and is, for the most part, inadequately known.

The present contribution is an attempt to review the Brazilian semionotid taxa (Lepidotes piauhyensis, Lepidotes sp. 1 from the Iguatu Basin, L. roxoi, L. souzai, L. alagoensis, L. wenzae, and Araripelepidotes temnurus) with a critical discussion of the specific status of some taxa named using fragmentary material (Lepidotes mawsoni, L. llewellyni, L. oliveirai, and L. dixseptiensis).

Katia GONZÁLEZ-RODRÍGUEZ & Víctor-Hugo REYNOSO: A new Notagogus (Macrosemiidae, Halecostomi) species from the Albian Tlayúa Quarry, Central Mexico
[pp. 265-278, 8 figs., 1 tab., 1 app.]

A new Notagogus species from the Albian Tlayúa Quarry in Puebla, Central Mexico is described and represents the only European macrosemiid genus in the deposits. Notagogus novomundi sp. nov. is characterized by a small size, a rounded dermopterotic, a short preobital region, big eyes, and unique strong and pointed coronoid teeth. A cladistic analysis supports the inclusion of the new macrosemiid in the genus Notagogus, as sister taxon of Notagogus helenae supported by the presence of two rows of supraorbitals. Both taxa branch off at the base of Notagogus. In this analysis Neonotagogus cannot be considered a different genus to Notagogus since this taxon falls within a polytomy with all Notagogus species. Stratigraphic information suggests a double migration of the family from its original distribution in Tethys Ocean to the west, following the aperture of the northern part of the Atlantic Ocean until Mexico: one within Notagogus and another one within its sister clade comprised by all other macrosemiid genera.

Gloria ARRATIA: Mesozoic halecostomes and the early radiation of teleosts
[pp. 279-315, 17 figs., 1 tab.]

An evaluation of the knowledge of advanced actinopterygians during the last 150 years reveals notable progress in the understanding of halecomorphs and teleosts, especially progress in the last 30 years. The unnatural taxon Holostei prevailed during most of the 20^th century, and only recently, have taxa such as Halecostomi, Halecomorphi and Teleostei (which include part of the holosteans) been recognized as monophyletic units. New taxa, such as the Halecomorphi with the †Parasemionotiformes at the base, and the Teleosteomorpha including the stem-group teleosts (e.g., †aspidorhynchiforms, †pachycormiforms) and "true" teleosts have been put forward. Despite the progress, groups such as †Parasemionotiformes, †Caturoidea, †Ionoscopiformes, †Pachycormiformes and †'Pholidophoriformes' still need major revisions to clarify their contents and phylogenetic relationships. Although there is apparently no doubt regarding the monophyly of the main teleostean lineages, e.g., the Elopomorpha, Osteoglossomorpha and Clupeocephala, their phylogenetic relationships remain unresolved. Three hypotheses have currently been put forward regarding the phylogenetic position of elopomorphs versus osteoglossomorphs and more advanced teleosts, the clupeocephalans. These hypotheses are strongly biased by the selection of taxa, e.g., Recent forms or fossil plus Recent forms. The sister group of Teleostei is still unresolved. Possible sister groups are the amiids, lepisosteids, Dapedium, pycnodontiforms, pachycormiforms and aspidorhynchiforms. Their relative positions in the cladogram changes when different outgroups are used. The living sister group (Amia or Lepisosteus) of Teleostei is similarly still unknown.

The Teleostei, the largest group of vertebrates today, had a modest beginning, presumably in the Late Triassic. They underwent an extraordinary radiation throughout the Mesozoic, especially during the Late Jurassic when several of the modern teleostean lineages made their entrance in the history of fishes. Interestingly, none of the Jurassic genera have been recovered in the Early Cretaceous. All Late Triassic and Jurassic teleostean genera had, apparently, a reduced geographical distribution and lived a few millions years to be replaced by new fishes.

J. Ralph NURSALL & Luigi CAPASSO: Gebrayelichthys (novum), an extraordinary genus of neopterygian fishes from the Cenomanian of Lebanon
[pp. 317-340, 15 figs., 1 tab.]

Gebrayelichthys, gen. nov., comprising one or more species, is remarkable in appearance. Specimens are laterally compressed and the body is from 1.8 times to about twice as deep as long (MD/SL³1.8). Head and trunk contribute about equally to the length of the body. The trunk is extended dorsad by a tall, narrow crest, which is supported anteriorly by a stout, dermal bony column of uncertain homology. The fleshy part of the dorsal crest carries the pterygiophores of the dorsal fin or its vestige, which extends the length of the trailing edge of the crest. Ventrally, the abdominal trunk forms a keel, also supported anteriorly by a stout, dermal bony column, and covered laterally by bony plates. The ventral keel extends about the same distance below the vertebral column as the dorsal crest extends above it. The trailing edge of the ventral keel is protected by plate-like scutes, each bearing a short, stout spine. The ventral keel contained much of the viscera. There is a prominent cloacal vestibule at the ventralmost part of the keel; the pelvic fins arise from the anterior wall of the vestibule. The pectoral fins arise post-cranially about two-thirds of the way up the keel. The caudal fin has not been preserved in any specimen seen. The skull has a pycnodontoid appearance, with orbits placed high beneath a frontal flexure, and an elongated, downward pointing snout. The vomer bears a few pointed teeth. The structure of the lower jaw is unclear in all the specimens; the mandible is either missing or much foreshortened. The notochord persists in the vertebral column. Scales are reduced to small, widely spaced dermal denticles, limited to the axial trunk and the base of the dorsal crest. Gebrayelichthys is envisaged as a drifting pelagic fish, feeding on plankton and feeble nekton. Given the conservatism of homeobox genes, it is suggested that experimental genetic manipulation of development of Recent fish might be useful to model the origin of some phylogenetically important characters of fossil fish.

Francisco José POYATO-ARIZA & Sylvie WENZ: The new pycnodontid fish genus Turbomesodon, and a revision of Macromesodon based on new material from the Lower Cretaceous of Las Hoyas, Cuenca, Spain
[pp. 341-378, 15 figs., 1 tab., 3 apps.]

The nicely preserved new material of a pycnodontid fish previously reported as Macromesodon aff. M. bernissartensis has triggered a revision of this genus. As a result, it is evident that the holotype of the type species, M. macropterus, is quite different from all of the butterfly fish-like specimens that have been called this for over a century. Turbomesodon gen. nov. is created for these fishes. The type species is the one from the Solnhofen area, T. relegans gen. et sp. nov.; the Las Hoyas material is assigned to another new species, T. praeclarus; and T. bernissartensis is the third species of this new, monophyletic genus. The presence of a nasal bone in pycnodontiforms is confirmed for the first time. The occurrence of a dermosphenotic bone that is interpreted as partially independent and partially fused to the dermopterotic is an unusual feature described for the first time in pycnodonts. The new genus Turbomesodon has one autapomorphic character, the presence of a supracloacal scale, a differentiated scale of the cloacal region that is defined herein. A juvenile specimen of T. praeclarus gen. et sp. nov. is one of the smallest specimens of pycnodontiform fish currently known.

Jeff LISTON: An overview of the pachycormiform Leedsichthys
[pp. 379-390, 8 figs.]

A historical review of work on the Callovian actinopterygian fish Leedsichthys is given, and unresolved issues regarding its type material, taxonomic position and palaeobiology are highlighted. Collections and archival research reveal two previously unrecognised exceptionally complete specimens, which should be critical to the future understanding of this animal.

René ZARAGÜETA BAGILS: Basal clupeomorphs and ellimmichthyiform phylogeny
[pp. 391-404, 7 figs., 1 app.]

The Ellimmichthyiformes is a fossil group of clupeomorphs (Teleostei). They include the genus Paraclupea, Diplomystus, and Ellimmichthys. Paraclupea contains one species, P. chetungensis from the Lower Cretaceous Chawan Formation of eastern China; Diplomystus contains four species, D. dentatus from the lower Eocene freshwater deposits of the Green River Formation, Wyoming, U.S.A., D. shengliensis from the middle Eocene freshwater deposits of eastern China, D. birdi from the Cenomanian (Upper Cretaceous) marine deposits of Hakel and Hjoula, Lebanon, D. dubertreti from the Santonian (Upper Cretaceous) marine deposits of Sahel Alma, Lebanon; Ellimmichthys contains at least three species, E. longicostatus, from the Lower Cretaceous of Bahia, Brazil, E. goodi from the Lower Cretaceous deposits of Equatorial Guinea and at least one undescribed species from the Lower Cretaceous marine deposits of the Morelos Formation, Tepexi de Rodriguez, Puebla, Mexico. A phylogenetic analysis comprising 56 characters for 15 taxa has been made. It is shown that Diplomystus is not monophyletic, and D. dubertreti is more closely related to other Ellimmichthyiformes than to other Diplomystus species; Sorbinichthys elusivo is an ellimmichthyiform. "Diplomystus" solignaci is also included in the Ellimmichthyiformes. The position of Ezkutuberezi carmeni from the freshwater deposits of the Lower Cretaceous of the Basque Country (Spain) and the undescribed Ellimmichthys from the marine deposits of the Lower Cretaceous of Puebla, Mexico, is analyzed under the proposed hypothesis. The implications of these features regarding clupeomorph phylogeny are discussed. The puzzling biogeographic consequences of the phylogenetic hypothesis proposed are interpreted under the hypothesis of a scarce fossil record concerning basal clupeomorphs. This hypothesis is corroborated by the low correlation between stratigraphic data and phylogenetic hypothesis.

Peter L. FOREY: A three-dimensional skull of a primitive clupeomorph from the Cenomanian English Chalk, and implications for the evolution of the clupeomorph acusticolateralis system
[pp. 405-427, 13 figs., 1 app.]

A three-dimensional skull of a †paraclupeid is described and referred to the genus †Diplomystus based on the shape of the dorsal scutes. All other †paraclupeids are known only from flattened or nearly flattened specimens. Therefore, this skull provides hitherto unavailable data on delicate braincase structures. This study allows a more complete assessment of primitive clupeomorph conditions and contributes to our understanding of how the complex specialisations of the acusticolateralis system in Recent clupeiform fishes developed. All are absent from †paraclupeids. A phylogeny is proposed (†Paraclupeidae (†Spratticeps (†Santanaclupea, †Denticeps, clupeids))) which acknowledges a sequential acquisition of acusticolateralis specialisations. Additionally, some derived characters are identified within the †paraclupeids such as excavated parietals and enlarged entopterygoid teeth occluding with enlarged teeth upon a consolidated basibranchial toothplate.

Terry GRANDE & Mario de PINNA: The evolution of the Weberian apparatus: A phylogenetic perspective
[pp. 429-448, 11 figs., 1 app.]

The evolution of the Weberian apparatus in otophysan fishes has been a source of confusion and debate among ichthyologists. This paper reexamines this debate in light of a proposed sister-group relationship between clupeomorphs and ostariophysans. Results from this study suggest that the Weberian apparatus may not have evolved as a single unit as indicated by the presence of a tripus-like structure found in some clupeomorphs. Otophysic structures thought to be restricted to otophysans but found in some clupeomorphs (e.g., pristigasteroids) may reflect a possible common homology. Although not intended to be a revision of otocephalan relationships, this paper provides a reexamination of the anterior vertebral and otophysic morphology of the group. Our results suggest that important phylogenetic information from the anterior vertebral region in these fishes may provide new insight into the sister-group relationship between Clupeomorpha and Ostariophysi as proposed by LECOINTRE & NELSON (1996). New interpretations for the homologies of certain Weberian ossicles (e.g., claustrum and tripus) are also proposed based on developmental, topological and phylogenetic data. A cladistic analysis of all informative characters (e.g., skull, caudal skeleton) is necessary to test hypothesized homologies based on the anterior vertebral characters proposed here.

Chelsea R. HERMUS, Mark V. H. WILSON & Andrew MACRAE: A new species of the Cretaceous teleostean fish Erichalcis from Arctic Canada, with a revised diagnosis of the genus
[pp. 449-461, 8 figs.]

A second species of the enigmatic fossil genus Erichalcis, E. conspicua sp. nov., is described from Late Early Cretaceous (middle Albian) beds of the Macdougall Point Member, Christopher Formation, at Dragon Mountain, Axel Heiberg Island, Nunavut, Canada. The new species differs from the type species E. arcta FOREY, 1975, from the Albian of the Loon River Formation, southern Northwest Territories, Canada, in the robust nature of its mid-lateral scutes and the angle of inclination of the dorsal and ventral scute processes. Its occurrence in the Albian of the high Arctic extends the geographic range of Erichalcis and suggests that the genus may be a useful indicator of an Albian age.

Specimens of a ventral-scuted form from the Loon River Formation, previously included within Erichalcis arcta, belong to a different, as yet unnamed species, probably a member of the Clupeomorpha. Erichalcis itself possesses mid-lateral scutes but not abdominal scutes.

A second species of teleost from the Dragon Mountain locality, with ventral scutes that are unlike those of known clupeomorphs, is briefly described in open nomenclature.

Hans-Peter SCHULTZE: Mesozoic sarcopterygians
[pp. 463-492, 10 figs., 4 apps.]

Only two piscine sarcopterygian groups, actinistians and dipnoans, survived into the Mesozoic. They peak in species diversity at the beginning of the Mesozoic, in the Early Triassic. A second peak of actinistian diversity falls into the marine Late Jurassic, whereas dipnoans are more diverse in freshwater deposits of the Late Triassic and the Neogene of Australia. A connection with catastrophic events cannot be shown, only the radiation in the Early Triassic could be the result of faunal change at the Permo-Triassic boundary. As advanced sarcopterygians, actinistians and dipnoans are quite distinct from each other and from other Mesozoic osteichthyans. The actinistians are very well known. Knowledge of Mesozoic and Cenozoic dipnoans has progressed during the last 20 years beyond tooth plates.

Lionel CAVIN & Peter L. FOREY: New mawsoniid coelacanth (Sarcopterygii: Actinistia) remains from the Cretaceous of the Kem Kem beds, Southern Morocco
[pp. 493-506, 7 figs.]

We describe newly discovered remains of mawsoniid coelacanths from the ?Cenomanian Kem Kem beds of southern Morocco, housed in The Natural History Museum (BMNH) in London and in the Musée des Dinosaures (MDE) in Espéraza, France. MDE F36 is an otico-occipital portion of the braincase of a moderate sized actinistian fish. It comprises the dermal bones of the posterior skull roof dorsally and the endocranial neurocranium ventrally. BMNH P.64127 is part of an ethmo-sphenoid. They are clearly from different-sized individuals. MDE F36 is referred to Mawsoniidae indeterminate and BMNH P.64127 to cf. Mawsonia lavocati with caution, because of difficulties, or even impossibility, to compare non-homologous skull remains from different species. MDE F36 shows that a species distinct from Mawsonia gigas, M. ubangiana, M. tegamensis and probably M. libyca was present in North-western Africa during the Cenomanian. MDE F36 shares with Axelrodichthys araripensisextrascapulars incorporated to the postparietal shield where a median element persists.

Niels BONDE: An Early Cretaceous (Ryazanian) fauna of "Purbeck-Wealden type" at Robbedale, Bornholm, Denmark
[pp. 507-528, 16 figs., 1 tab.]

A short review of the fossil vertebrates in W-Denmark and Bornholm is presented as an introduction to the Lower Cretaceous Nyker Group. At Robbedale, SW-Bornholm, in "Carl Nielsen's sand pit", the best Danish Cretaceous vertebrate fauna is disclosed in the basal Jydegaard Fm. (Ryazanian, equivalent to late Berriasian age). This fauna is contained in a half to one meter rusty clay bed, the Neomiodon Bed, named for the mass mortality layers of this bivalve, and in 2-3 m of sands immediately above. The fish fauna comprises hybodont sharks (two or three species), Lepidotes, an amioid, a pycnodont, Pleuropholis and some other stem-group teleosts. The tetrapods are undetermined turtles, the crocodile Pholidosaurus, probably one more genus, and some unique fully terrestrial vertebrates: one scincomorph lizard, a dromaeosaurian dinosaur and a sauropod. There are plants and freshwater snails, and the environment indicated is that of a back barrier beach sand outside a brackish lagoon with dessication of pools causing mass mortality of gastropods and bivalve mass mortality probably caused by dinoflagellate blooms, while only some fishes seem to be affected by this mortality agent.

Valentina KARATAJUTE-TALIMAA & Valentas KATINAS: Occurrence of Triassic fishes in the East Baltic Region
[pp. 529-534, 4 figs.]

In the East Baltic Region (Lithuania and Kaliningrad district of Russia), the Lower Triassic deposits are subdivided into Purmaliai and Nadruva groups, which correspond to the Induan and Olenekian stages respectively. The Purmaliai Group is subdivided into Nemunas, Palanga and Tauragé formations. Shallow-water basin clay, silt, sand with intraformational conglomerates and oolitic sandy limestones compose the Tauragé and Sarkuva formations. The microremains of indeterminate actinopterygian fishes – scales, lepidotrichia and teeth – were found in the upper part of the Tauragé Formation, in two intervals (731.0-737.0 m and 745.0-751.0 m) of stratotypic borehole Vladimirovo-1 and in sandy aleurolitic intercalations of borehole Nida-44 (369.0 m).

Meemann CHANG & Desui MIAO: An overview of Mesozoic fishes in Asia
[pp. 535-563, 11 figs.]

Although the Mesozoic fishes in Asia are abundant, their adequate studies are not. Among the publications, many are in the languages other than English and often in the journals not readily available. This paper has brought much of that information together, and based on it, has concluded on the patterns of succession, distribution, and tectonic implications of the Mesozoic fish faunas in Asia.

The integral parts of the present-day Asia had gone through drastic changes during the Mesozoic, and so had the freshwater fish faunas dwelled on them. The Triassic freshwater faunas in northern Asia are characterized by primitive actinopterygians such as palaeoniscids, scanilepids and perleidids. In contrast, the marine fish fauna in southern China contains edestids, hybodontiforms, perleidids, saurichthyids, birgerids and coelacanthiforms, with some primitive forms similar to those from the northern coast of the Mediterranean. The wide distribution of the Triassic freshwater fishes in Asia, even in part of southern China, suggests a more extensive landmass in Asia during the Triassic than previously reconstructed. The Jurassic freshwater fish faunas had even more extensive distributions, consisting of palaeoniscids, coccolepids, ptycholepids, 'pholidophoriforms', and primitive acipenseriforms. The marine Jurassic fishes include a pycnodontid from Tibet as well as coccolepids, 'pholidophorids', semionotids, amiiforms and ceratodontids from southern China's Hunan Province. Aside from reduced marine fish distributions, the Jurassic fish faunas were subjected to the similar conditions as those of the Triassic. The Early Cretaceous fish faunas from the mainland Asia plus Korea and Kyushu, Japan are all freshwater and consist mostly of archaeomaenids and teleosts, mainly osteoglossomorphs in the north and ichthyodectiforms and clupeomorphs in the south. These forms are divided into three assemblages, which are distributed in three SW-NE oriented areas parallel to the tectonic structures. The Late Cretaceous fish faunas are not well studied, but appear to be represented by more advanced, and more cosmopolitan, teleosts.

The succession of the Mesozoic fish faunas in Asia as elsewhere in the world reveals: 1) the distinctive compositions among the three periods of the Mesozoic, (2) the tectonic control of the drainages and thus its impact on the distributions of the freshwater fish faunas, and (3) the freshwater environments as the refuge for the pre-existing marine fishes.

Haruka YAMAGISHI: Elasmobranch remains from the Taho Limestone (Lower-Middle Triassic) of Ehime Prefecture, Southwest Japan
[pp. 565-574, 5 figs.]

Over 350 isolated teeth, many placoid scales and some cephalic spines of hybodont and synechodontiform sharks occur together with conodonts in the Taho Limestone (Smithian to Anisian), Ehime Prefecture, Southwest Japan. Most of the teeth range from 0.4-0.8 mm in height (max. 2.0 mm), 0.8-1.4 mm in length (max. 4.2 mm), and belong to Hybodus, Polyacrodus, and Synechodus. All of the cephalic spines belong to Arctacanthus. The new species Synechodus triangulus and Arctacanthus exiguus are described.

Mark V. H WILSON & John C. BRUNER: Mesozoic fish assemblages of North America
[pp. 575-595, 4 figs.]

The Mesozoic record of fossil fishes in North America is characterized by temporally and geographically discontinuous areas of strength. Important assemblages of marine fishes are known from the Lower Triassic of Western Canada, the Albian through Maastrichtian of the Western Interior of both USA and Canada (culminating in the famous "Kansas Chalk" fauna), and the Santonian to Maastrichtian of the Gulf and Atlantic Coasts of the USA. Important freshwater fish assemblages include those of the Triassic Dockum and Chinle groups in Western Interior USA, the Triassic/Jurassic Newark Supergroup in Eastern USA, the Middle Jurassic Sundance and Wanakah formations of Western Interior USA, and the Upper Cretaceous fluvial formations of the Western Interior of Canada and USA.

Chondrichthyans are common in marine and in fluvial formations, but not in lacustrine ones; actinopterygians are common in nearly all assemblages. Lungfishes are common in freshwater formations during the Triassic and Jurassic, but disappear from the Western Interior record during the Early Cretaceous. Coelacanths are common in marine and some freshwater formations in the Triassic, disappearing from the Western Interior record after the Middle Jurassic. There are isolated reports of both lungfishes and coelacanths from the Upper Cretaceous of the Atlantic Coast.

Certain diverse and geologically complex assemblages, such as those of the 'Kansas Chalk' and the Cretaceous of the Gulf and Atlantic Coasts, would be much more accessible to future researchers after completion of comprehensive reviews of the diversity and taxonomy of their contained fishes. Overall, study of North American Mesozoic fishes would benefit from greatly increased local and international cooperation and collaboration, thus stimulating interest in these fishes by more researchers and leading to an increased pace of discovery.

Adriana LÓPEZ-ARBARELLO: The record of Mesozoic fishes from Gondwana (excluding India and Madagascar)
[pp. 597-624, 6 figs., 11 tabs.]

Mesozoic fish faunas from the Gondwanan continents of South America, Africa, Australia, and Antarctica are relatively more poorly known than their northern counterparts. The best studied faunas known so far are those of the Jurassic (Oxfordian) of Quebrada del Profeta in Chile, of the Lower Cretaceous (Aptian-Albian) of the Araripe Basin in northeastern Brazil, and of the Upper Cretaceous (Cenomanian) of Lebanon and Morocco. Many other promising localities have been reported, but they need to be revised or thoroughly studied in the light of modern ideas of phylogeny and biogeography. These include the Triassic faunas of the Cuyo Basin in Argentina and of Gosford, Brookvale and St. Peters in Australia, the Jurassic faunas of the Cañadón Calcáreo Formation in Argentina, Talbragar in Australia, the Stanleyville Beds in Africa, and the Cretaceous faunas of the La Cantera and Lagarcito Formations of Argentina, the Apon Formation of Venezuela, many Albian fish assemblages of Africa, and the Santa Marta Formation of Antarctica among others. The geographic distribution of known Mesozoic fish localities on these continents mainly follows the more densely populated and/or geologically better explored areas. Stratigraphically, the Mesozoic fish record is far from complete, with the Cretaceous generally better represented than either the Triassic or the Jurassic on all continents. At the current state of knowledge, Mesozoic fish evolution in Gondwana seems to have followed the same general pattern as in the Northern Hemisphere, but too little is still known to establish the detailed sequence of events. Mesozoic fish faunas from Gondwana have already been demonstrated to be of great importance for our understanding of fish evolution and biogeography, and there is a great potential for further discoveries and studies.

Guntupalli V. R. PRASAD, Brijesh K. MANHAS & Gloria ARRATIA: Elasmobranch and actinopterygian remains from the Jurassic and Cretaceous of India
[pp. 625-638, 5 figs.]

Disarticulated remains of elasmobranch and actinopterygian fishes recovered from the Middle to Upper Jurassic Kota Formation and the Lower Cretaceous Gangapur Formation (Pranhita-Godavari valley, India) are described. The fish remains from the Kota Fm. include the elasmobranchs ?Polyacrodus and Lissodus and the actinopterygians Lepidotes cf. L. deccanensis, Semionotidae gen. et sp. indet., Ionoscopus-type teeth, and Actinopterygii indet. The elasmobranchs of the Kota Fm. come from a single section exposed west of Paikasigudem village, Rebbana Mandalam, Adilabad District, Andhra Pradesh, whereas the actinopterygians occur in all six investigated sections. The Lower Cretaceous Gangapur Fm., which unconformably overlies the Kota Fm., has yielded the first actinopterygian teeth and ganoid scales. The teeth compare well with those of Caturus and Gyrolepis. Some indeterminate actinopterygian teeth are also present in this collection.

David BELLWOOD & Andrew HOEY: Feeding in Mesozoic fishes: a functional perspective
[pp. 639-649, 5 figs., 1 app.]

The potential feeding abilities of Mesozoic fishes are investigated using analyses of functional morphospace. The closing lever ratio of the lower jaw and the relative jaw length are used to compare potential feeding modes among Mesozoic and Cenozoic fish faunas. Preliminary analyses support earlier suggestions that there was an increase in durophagy in actinopterygian fishes in the Norian. Furthermore, the data highlight the prevalence of low force-transmission feeding modes in Jurassic teleosts and the role that this feeding mode may have played in the radiation of this group. Analyses of functional morphospace provide an objective basis for evaluating the potential feeding abilities of both extant and extinct fishes. It provides a novel tool for investigating the abilities of fishes that is largely independent of taxon or age.

The Mesozoic was an important time in the evolution of chondrichthyan and actinopterygian fishes because it was then that most of the modern groups first entered the fossil record and began to radiate. By the end of the era, many archaic forms had disappeared and the foundation had been laid for the ichthyofauna that now exists. Despite this significant evolutionary change, before 1990 there had been little concerted research done on Mesozoic fishes and no synopsis or compilation of the systematics and paleoecology of Mesozoic fishes had been published, not even for single groups. To remedy this deficiency, Gloria ARRATIA initiated the symposium "Mesozoic Fishes". The first meeting "Mesozoic Fishes – Systematics and Paleoecology" was held in Eichstätt on August 9 to 12, 1993 and the first volume of Mesozoic Fishes, including 36 papers concerning elasmobranchs, actinopteygians and sarcopterygians and the paleoecology of certain important fossil localities was published in 1996. Gloria ARRATIA and Hans-Peter SCHULTZE organized a second Symposium held in Buckow, a small village near Berlin on July 6 to 10, 1997. The results of the symposium were published in "Mesozoic Fishes 2 – Systematics and Fossil Record" and included 31 papers.

Andrea TINTORI, Markus FELBER and Heinz FURRER organized the third symposium that was held in Serpiano, Monte San Giorgio from August 26 to 31, 2001. Serpiano is a beautiful, quiet place surrounded by mountains and forests in the Swiss Alps. The program of oral and poster presentations was intense, with more than 70 contributions from colleagues from 17 various nations. The oral presentations during the morning sessions were followed by visits to different fossiliferous sites, to the old farm house of the family Peyer where we enjoyed the hospitality of the family, and by evening receptions enlightened by the excellence of the Italian and Swiss cousine. For many in the audience, this was their first attendance to a symposium on Mesozoic Fishes; for many of us it was refreshing to see the many new faces involved in the studies of Mesozoic fishes.

The results of the symposium presented in part in this volume reflect the current state of knowledge of Mesozoic fishes. Because of the historical moment that we are living, the beginning of the third millennium, some authors were requested to prepare special evaluations concerning the state of knowledge of major Mesozoic fish groups such as chondrichthyans, halecostomes and sarcopterygians and of the fossil record of continents such as North America, Asia, South America and Africa. Unfortunately, some of the planned contributions such as the evaluation of Mesozoic basal actinopterygians and of some continents such as Europe, are not available. As the number of contributions on chondrichthyans has greatly increased in comparison with those in Mesozoic Fishes 1 and 2, new information on chondrichthyans, actinopterygians and sarcopterygians are presented with most of the themes centered on systematics of chondrichthyans and actinopterygians – clear direction where the preference of fish research moves in a dynamic and exiting phase.