Most lungfish tooth plates, that are arranged in radiating ridges derived from the fusion of separate cusps in young juveniles, are based on a framework of enamel, mantle dentine and bone that encloses a mass of specialized dentines forming the occlusal surface. In most taxa, the specialized dentines are interdenteonal and circumdenteonal dentine, but a few derived genera have petrodentine as well. Petrodentine, as originally defined, describes a specific form of hypermineralized dentine in adult tooth plates of the Recent African lungfish Protopterus. The ontogeny of fossil and Recent lungfish tooth plates demonstrates that petrodentine is derived by continuous enhancement of the hard tissue of the primary core of the initially isolated cusps of the tooth plate, and that interdenteonal dentine with denteons of circumdenteonal dentine is a secondary development in the tooth plate around and below the first formed cusps of the ridges. In dipnoans that lack petrodentine in adults the primary core of the cusps is not enhanced, but is removed by wear. The hard tissues of the dipnoan tooth plate provide useful characters for defining dipnoan taxa, as do the differing arrangements of the tissues in each species. Details of the arrangement of the enclosed specialized dentines are surprisingly variable among genera, and are significant for the structure and function of the tooth plate. Little regularity of structure is discernible in the histology of tooth plates of early dipnoans, but derived genera have more predictable structure. Consistent with other uniquely dipnoan characters, like the composition of the dermal skull, an evolutionary progression is evident within the group in the fine structure of the dentition, and, as with the bones of the dermal skull, little similarity is demonstrable between the dentines of dipnoans and tetrapods.

Exceptionally complete material of a new stethacanthid chondrichthyan, Akmonistion zangerli, gen. et sp. nov., formerly attributed to the ill-defined genera Cladodus and Stethacanthus, is described from the Manse Burn Formation (Serpukhovian, Lower Carboniferous) of Bearsden, Scotland. Distinctive features of A. zangerli include a neurocranium with broad supraorbital shelves; a short otico-occipital division with persistent fissure and Y-shaped basicranial canal; scalloped jaw margins for 6–7 tooth files along each ramus; a pectoral-level, osteodentinous dorsal spine with an outer layer of acellular bone extending onto a brush-complex of up to 160% of neurocranial length; a heterosquamous condition ranging from minute, button-shaped, flank scales to the extraordinarily long-crowned scales of the brush apex; and a sharply up-turned caudal axis associated with a broad hypochordal lobe. The functional implications of this anatomy are discussed briefly. The rudimentary mineralization of the axial skeleton and small size of the paired fins (relative to most neoselachian proportions) are contrasted with the massive, keel-like, spine and brush complex: Akmonistion zangerli was unsuited for sudden acceleration and sustained high-speed pursuit of prey. Cladistic analysis places Akmonistion and other stethacanthid genera in close relation to the symmoriids. These taxa are located within the basal radiation of the chondrichthyan crowngroup, but more detailed affinities are uncertain. They may represent a plesion series on the holocephalan stem lineage, or a discrete clade branching from the base of the elasmobranch lineage.

Two Jurassic–Cretaceous anurans are described based on well-preserved specimens from the lower part of the Yixian Formation, western Liaoning Province, northeastern China. One specimen, from the Heitizigou site, documents a new genus and species, and the second, from the Sihetun site, is the holotype and only known specimen for the recently named Callobatrachus sanyanensis. Phylogenetic relationships of the major archaeobatrachian anuran clades are investigated with incorporation into the analysis of selected (well-established) early fossil taxa. The new taxon named and described in this paper is placed as the representative of a distinct archaic anuran clade, and Callobatrachus is considered to be an ingroup member of the Discoglossidae, constituting the earliest record of the family from Asia. The oldest known fossil anuran, Prosalirus from the Early Jurassic of Arizona, is grouped with Notobatrachus as sister taxa, and the two together form the most basal clade of Anura. Contradicting the widely accepted Leiopelmatidae–Discoglossidae sistergroup relationship, new evidence places the Leiopelmatidae as the most basal extant familial group and the sister group to other archaeobatrachian clades. The relationships and classification of the major archaic anuran clades are discussed, based on the phylogenetic results of this study.

A specimen collected from the Lower Jurassic Lower Lufeng Formation of Yunnan, China, represents a new genus and species of therizinosauroid theropod. It comprises an incomplete left mandibular ramus and is here named Eshanosaurus deguchiianus. Distinctive characteristics of the new species include the presence of a round fenestra in the posterior portion of the dentary, small size of tooth denticles, and denticles almost perpendicular to the anterior and posterior edges of tooth crowns. The discovery of Eshanosaurus deguchiianus extends the record of therizinosauroids from the Early Cretaceous back to the Early Jurassic. Recent phylogenetic hypotheses placing therizinosauroids within Coelurosauria imply this is the oldest known coelurosaur, and that diversification of the group began much earlier than was previously indicated by the fossil record.

Most of South America's diverse avian fossil record is derived from terrestrial deposits. A Late Miocene to Early Pliocene marine avian assemblage is reported here from the Bahía Iglesa Formation of north-central Chile. Sulidae, Phalacrocoracidae, Pelagornithidae, Diomedeidae, and Spheniscidae reported here are the earliest occurrences in Chile. The presence of the Chilean spheniscid penguin may prove significant in the taxonomy and radiation of the genus Spheniscus.

A newly-discovered skeleton of Terminonaris (=Teleorhinus) robusta (=robustus) from the early Turonian marine deposits of east-central Saskatchewan affords the opportunity for a detailed description of the anatomy of this species and its placement in the context of other known species of this genus. The specific diagnosis of T. robusta and the generic diagnosis of Terminonaris are established. Terminonaris robusta differs from the type species T. browni mainly in size-related features. Teleorhinus mesabiensis Erickson, 1969 is placed into the synonymy of Terminonaris robusta. The genus can be diagnosed by features of the anterior end of the snout, sutural relationships of the bones surrounding the orbit, and the structure of the occiput. A phylogenetic analysis based upon data drawn from the new material suggests that Terminonaris is not a pholidosaurid but is, instead, closely related to Dyrosaurus. This analysis continues to support the hypothesis that long-snouted crocodyliforms of the traditional “mesosuchian grade” form a clade.

The original description of Caypullisaurus (Ichthyosauria: Ophthalmosauria) depended on the orientation of the fins of the holotype. Later, the forefins of this taxon were reoriented contrary to the original description. The arrival of the holotype carcass at the sea floor is analyzed taphonomically such that the original interpretation is confirmed. The analysis of the homologies of the forefin elements also confirms that the topological criteria developed for the identification of the primary axis of all Ichthyosauria are also applicable for Caypullisaurus. A comparison with the forefins of other Callovian and Late Jurassic ichthyosaurs shows that Caypullisaurus belongs to the Ophthalmosauria and that the forefins of this clade are more diverse than previously supposed.

The Bromacker locality in the Tambach Sandstone of Germany represents the first significant Lower Permian assemblage of terrestrial tetrapods outside of North America. The left forelimb (humerus, radius, ulna, carpus, metacarpals, and digits) and serveral vertebrae of subadult Seymouria sanjuanensis are described. The manus phalangeal formula is 2-3-4-4-3.

A new triconodont molariform tooth of Indozostrodon simpsoni, gen. et sp. nov., from the Early Jurassic Kota Formation is described and compared with other triconodont mammals. This nontherian triconodont mammal shows distinct dental morphological attributes which place it in the family Megazostrodontidae. The association of both nontherian and a number of therian mammals reported earlier from the Kota Formation undoubtedly points to a rapid diversification of the early mammals in the Early Jurassic. Remarkable similarity of this new taxon with other triconodont mammals points to a Pangaean distribution of these early mammals and supports the thesis that the continents were confluent at least up to the Early Jurassic and intercontinental migration was taking place.

Nementchatherium senarhense, gen. et sp. nov. from the Middle–Late Eocene of Bir El Ater (Algeria) is described and assigned to the subfamily Herodotiinae (Macroscelidea). This genus and the other primitive elephant-shrews are compared with the Louisininae (Hyopsodontidae, Condylarthra) from the Early Paleogene of Europe. These groups have been included in a phylogenetic analysis based on dental characters, in order to clarify the origin of Macroscelidea. Phylogenetic reconstruction suggests that Louisininae are belonging in the polyphyletic Hyopsodontidae except for Microhyus which is considered here as the sister-group the Macroscelidea. These results suggest a terrestrial interchange between Africa and Eurasia during the Early Eocene. The phylogenetic analysis suggests also that the Macroscelidea-Microhyus clade is closely related to the Proboscidea. Like molecular phylogenies, especially those concerning the African molecular clade (=Afrotheria), our results, provide evidence for a macroscelid-tethytherian relationship. However, if the Macroscelidea emerged from European “condylarth” at the Early Eocene as our data suggest, the Proboscidea are already differentiated in Africa during this period. Then, it seems that Macroscelidea and Proboscidea are paraphyletic. The assumption of a unique group of condylarthran type at the origin of Afrotheria (macroscelids, tethytherians, tubulidentates, tenrecid and chrysochlorid insectivores) cannot be excluded, but the current paleontological data do not fit with that hypothesis.

Archaeodesmana baetica, sp. nov. is a new water-mole (Desmaninae, Talpidae) from Purcal 4, a locality at the Miocene–Pliocene transition in southern Spain. It is characterized by a very large p2, larger than P2, and a p2/p3 ratio which is larger than in any known desmanine. Its I1 are bilobed. The premolars are very large in comparison with the molars, or, in other words, the mandibles and maxillae of this new species are greatly enlarged anteriorly. The new species is possibly close to the ancestry of Desmana.

A partial skull and lower jaw with associated postcranial skeleton of Didymoconus berkeyi Matthew and Granger, 1924 was recently collected from the late Oligocene of Lanzhou Basin, Gansu Province, China. Besides being the first discovery of this genus in the Lanzhou Basin, the new material of Didymoconus represents the most complete individual of this species. The new specimen is paleomagnetically bracketed between 27–30 Ma in the Lanzhou section and helps to refine the biostratigraphy of this species elsewhere in eastern Asia. The postcranial skeleton provides valuable insight into its locomotion apparatus and offers possible characters for phylogenetic positioning of this enigmatic form. An enlarged hand and claws, along with a strong forelimb and robust skull, suggest fossorial adaptations.

A new genus and species of basal gliriform mammal, Sinomylus zhaii, is described from the late Paleocene Tujinshan Formation of southern China. The new species is based on a fragmentary rostrum bearing a possible alveolus for a right P1 (DP1) or C (DC), well-preserved left P3–M2, and broken incisors and other cheek teeth. There is one pair of upper incisors. The incisor enamel has one layer of radial enamel microstructures and lacks Hunter-Schreger bands. P2 is small and conical. Both P3 and P4 consist of two main cusps. The molars are unilaterally hypsodont and have the typical eurymylid tooth pattern. Collectively, these features place the new genus as the sister-taxon to the clade comprising eurymylids and rodents.

The holotype of Priscodelphinus squalodontoides Capellini, 1878 and a second, more complete skull both derive from Miocene sediments of the Salento Peninsula (southern Italy). They are ascribed to Rudicetus, a new genus within the Kentriodontidae (Odontoceti, Cetacea). Rudicetus is characterized by a nearly symmetrical skull, condylobasal skull length of about 450 mm, rostrum 60 percent of the condylobasal length of skull, about 30 teeth in the upper tooth row, posterior teeth with accessory denticles, wide and knob-like premaxillary terminations, wide, flat and low vertex, nasals smaller than frontals at vertex, rectilinear anterior margin of nasal, nasal-frontal suture anteriorly convex, relatively narrow posterior portion of skull with occipital shield laterally constricted, and slender and anteroposteriorly elongated zygomatic process of squamosal. Rudicetus is referred to the subfamily Kentriodontinae because of its flat, wide, and low vertex. Rudicetus squalodontoides confirms the presence of kentriodontids from Italy and the Mediterranean Basin, as all previous reports were based on fragmentary specimens.

Four new ungulate species described here from the early middle Eocene Uzunçarsidere Formation, near Ankara, Turkey present a phylogenetic and biogeographic puzzle. The four species, known from jaws, teeth, and skull and postcranial fragments, share a suite of diagnostic dental features (selenolophodont molars, all lower molars lacking hypoconulids, premolars with metacones small or absent, and narrow, short premolar talonids) and are included in a single new genus, Hilalia. Hilalia saribeya, H. selanneae, H. sezerorum, and H. robusta are distinguished from each other by size and details of premolar morphology. Cladistic analysis indicates that although Hilalia shares a common ancestor with perissodactyls, hyracoids and some “condylarths” to the exclusion of artiodactyls, its position relative to those taxa is unresolved—the calcaneum lacks derived features of artiodactyl, perissodactyl or hyracoid calcanea, some features of Hilalia's molar morphology are convergent with features in some hyracoids, perissodactyls, and selenolophodont “condylarths”, and Hilalia has more primitive premolars than most members of those groups. The affinities of some other members of the Uzunçarsidere mammal fauna, including an embrithopod, marsupials, and a possible proboscidean, have suggested that central Anatolia may have served as a biogeographic crossroads for mammalian dispersal among Asia, Africa, and Europe during the early Paleogene. However, the absence of convincing links between Hilalia and any of the increasingly well-known Paleogene ungulates of Asia, Indo-Pakistan, and Africa, or those of Europe and North America suggests that our understanding of early Paleogene ungulate evolution and biogeography is far from complete.

Hambach 6C, a recently discovered middle Miocene vertebrate locality in northwestern Germany, produced the fourth occurrence of the extremely rare ruminant Orygotherium escheri. The new record is an isolated M3. In Central Europe, O. escheri is known only from lignitic deposits of zone MN5, and may have been restricted to swampy habitats. Figures and measurements of the lecto- and paralectotypes are published for the first time. The phylogenetic position of Orygotherium within the Ruminantia remains uncertain despite 160 years of research.

Few fossils have been described from the very rich localities of Kalimantsi in southwestern Bulgaria, and none from Hadjidimovo, in the same area. These deposits have produced one of the best collections of Chalicotheriidae from the late Miocene of Europe, increasing the diversity of the family, and providing the first definite evidence of the co-occurrence of both subfamilies, Chalicotheriinae and Schizotheriinae. The milk dentition of Ancylotherium is described for the first time; it confirms that this genus is close to, but different from, the American Tylocephalonyx. A chalicotheriine skull from Kalimantsi, with a characteristic tooth morphology, is referred to a new genus and species, Kalimantsia bulgarica. A revision of the taxonomy and systematics of European Chalicotheriinae leads us to discard “Macrotherium,” which is a junior synonym of Chalicotherium, to revive Anisodon Lartet for middle Miocene forms, and to suggest the extension of Kalimantsia into the latest Miocene of the Balkans.

In the late 19th century, rare fossil remains of a small chalicothere were recovered from early Miocene rocks of the John Day Formation of north-central Oregon. Totaling eight isolated teeth and four foot bones, and gathered by various collectors from several localities, these specimens were not at first recognized as chalicotheres, and were originally assigned to a dental species, Lophiodon? oregonensis, and a postcranial species, Moropus distans. All were assigned to the chalicothere genus Moropus by Holland and Peterson in 1914. The lack of precise geographic and stratigraphic data did not permit any definitive assessment of age, origin, or evolutionary stage.

We report here newly discovered teeth and foot bones of M. oregonensis found from 1994–1998 at precisely located levels in the John Day Formation. These new discoveries indicate that M. oregonensis occurs in upper John Day units but is absent from the lower part of the formation. One tooth occurs in proximity to a tuff dated at 22.6 ± 0.13 Ma, hence establishes a minimum age for the appearance of the species in North America. New dental and foot elements allow us to synonymize Moropus distans with M. oregonensis, now the type species of the genus Moropus. Additionally, a small chalicothere, probably M. oregonensis, occurs at four Arikareean Gulf Coast sites in north Florida and east Texas. It is suggested that these animals, along with the Oregon chalicotheres, represent relatively primitive populations inhabiting mesic coastal environments of the Pacific margin and southern United States in the early Miocene.