Postcranial anatomy of Haldanodon exspectatus (Mammalia, Docodonta) from the Late Jurassic (Kimmeridgian) of Portugal and its bearing for mammalian evolution

The postcranium of the Late Jurassic docodont Haldanodon exspectatus Kühne & Krusat, 1972 is represented by a partial skeleton and isolated bones of other individuals from the Late Jurassic (Kimmeridgian) of the Guimarota coal mine in Portugal. Haldanodon exhibits adaptations for a fossorial lifestyle such as stout and short limb bones and humeri with greatly expanded distal joints and strong deltopectoral crests. Short first and second phalanges and moderately curved and laterally compressed terminal phalanges with lateral grooves suggest that Haldanodon was a scratch-digger. The dorso-ventrally elongated, triangular scapula has a convex transverse profile with strongly laterally reflected anterior and posterior scapula margins, enclosing a deep trough-like 'infraspinous fossa'. A supraspinous fossa is not developed. The saddle-shaped glenoid facet is mainly formed by the coracoid and orientated antero-ventrally indicating a sprawling gait. No epiphyses were detected and the wide size range of humerus and femur possibly indicate a lifelong growth. Haldanodon is more derived than Morganucodon by complete reduction of the procoracoid, absence of the procoracoid foramen, and a peg-like coracoid. It shares with monotremes a postscapular fossa that is absent in Morganucodon . A PAUP analysis based on 280 cranio-dental and postcranial characters corroborated the position of Haldanodon above morganucodontids and below Hadrocodium .  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 145 , 219–248.     

Small theropod teeth from the Upper Jurassic coal mine of Guimarota (Portugal)

Isolated teeth of small theropod dinosaurs from the Upper Jurassic lignite coal mine of Guimarota (near Leiria, Portugal) are described and illustrated. The well known Upper Jurassic theropods from Europe,Archaeopteryx andCompsognathus, are the most common taxa in the Guimarota assemblage. One morphotype is closely related to an allosaurid theropod. Six further morphotypes of theropod teeth are also described, which are closely related to Cretaceous theropods such as dromaeosaurids, troodontids, tyrannosaurids,Richardoestesia andParonychodon. A Late Jurassic origin of these groups of theropods, which is very often postulated, is discussed.     

An amioid fish (Neopterygii, Amiiformes) from the Late Jurassic of the Iberian Peninsula

The first record of the bowfin order Amiiformes in the Late Jurassic of Portugal is reported. The single specimen comes from the Guimarota coal mine near Leiria in the Lusitanian basin. Here, Kimmeridgian strata that yielded abundant teeth, spines, and scales of selachians and actinopterygians are exposed below ground. The specimen described herein is the only disarticulated fish remain from this locality. It consists of jaw elements, parts of the palatoquadrate and opercular apparatus, an element of the postorbital series and some additional postcranial parts. The systematic position of the new specimen is discussed. The combination of characters allows assignment to the Amioidea rather than to other amiiform groups. Therefore, the specimen constitutes the first undoubted record of an amioid in the Late Jurassic of the Iberian Peninsula and contributes to the knowledge of Late Jurassic amiiform distribution patterns.     

Tooth Replacement in Late Jurassic Dryolestidae (Eupantotheria, Mammalia)

The discovery of juvenile dentitions of late Jurassic (Kimmeridgian) Dryolestidae (Eupantotheria, Mammalia) from Guimarota, Portugal, yields for the first time information on the mode of tooth replacement in therian mammals prior to the dichotomy of placentals and marsupials. As in extant placentals, tooth replacement occurs at all antemolar positions [incisors (I1–I4), canine (C), premolars (P1–P4)]. P1 and P2 have premolariform milk predecessors, whereas the large premolariform third (P3) and fourth premolars (P4) are preceded by molariform deciduous premolars (dP3, dP4). Tooth replacement takes place in two waves, at least in the lower jaw, with I₂, I₄, P₁, and P₃ in the first series and I₁, I₃, C, P₂, and P₄ in the second. P₄ is the last premolar to erupt, and it is present when the sixth molar (M₆) starts to break through. The reduced tooth replacement pattern of marsupials (with only dP3 being replaced postnatally) evolved secondarily from the primitive or plesiomorphic mammalian condition, which was retained in Dryolestidae and Eutheria.     

Multituberculaten-Zähne aus dem Ober-Jura von Porto das Barcas (Portugal)

An isolated m₁ from the Upper Jurassic of Porto das Barcas, Portugal, is described asKuehneodon barcasensis n. sp. It is similar toK. uniradiculatus G. Hahn 1978 from the Guimarota Coal Pit, Portugal, especially in subdivision of the first and third buccal cusps into two cuspules. But it differs fromK. uniradiculatus in the breadth of the cusp-rows: The buccal row is nearly twice as broad as the lingual cusps row, whereas inK. uniradiculatus both rows are nearly of the same breadth. Moreover, the m₁ ofK. barcasensis is only 1 mm long, whereas the m₁ ofK. uniradiculatus are 1.6-1.9 mm in length. A second tooth, a p₃, is tentatively grouped withK. barcasensis. It is of the same small dimensions as the m₁ (1 mm long). It bears four serrations, and two basal cuspules. The exact stratigraphical age of these teeth is unknown, but their close affinities to the taxa of the Guimarota Coal Pit make an Oxfordian to Kimmeridgian age probable.     

A tyrannosauroid dinosaur from the Upper Jurassic of Portugal

Fragmentary theropod remains from the Upper Jurassic (Kimmeridgian) of Guimarota, Portugal, represent a new taxon of theropod dinosaurs, Aviatyrannis jurassica gen. et sp. nov. Together with Stokesosaurus from the Morrison Formation of North America, Aviatyrannis represents the oldest known tyrannosauroid, indicating that tyrannosauroid origins may be found in the Middle–Late Jurassic of Europe/North America. Furthermore, current evidence suggests that early tyrannosaurs were rather small animals, which is in general accordance with their origin amongst the generally rather small coelurosaurs.     

Contemporaneous Trace and Body Fossils from a Late Pleistocene Lakebed in Victoria,Australia, Allow Assessment of Bias in the Fossil Record

The co-occurrence of vertebrate trace and body fossils within a single geological formation is rare and the probability of these parallel records being contemporaneous (i.e. on or near the same bedding plane) is extremely low. We report here a late Pleistocene locality from the Victorian Volcanic Plains in south-eastern Australia in which demonstrably contemporaneous, but independently accumulated vertebrate trace and body fossils occur. Bite marks from a variety of taxa are also present on the bones. This site provides a unique opportunity to examine the biases of these divergent fossil records (skeletal, footprints and bite marks) that sampled a single fauna. The skeletal record produced the most complete fauna, with the footprint record indicating a markedly different faunal composition with less diversity and the feeding traces suggesting the presence, amongst others, of a predator not represented by either the skeletal or footprint records. We found that the large extinct marsupial predator Thylacoleo was the only taxon apparently represented by all three records, suggesting that the behavioral characteristics of large carnivores may increase the likelihood of their presence being detected within a fossil fauna. In contrast, Diprotodon (the largest-ever marsupial) was represented only by trace fossils at this site and was absent from the site''s skeletal record, despite its being a common and easily detected presence in late Pleistocene skeletal fossil faunas elsewhere in Australia. Small mammals absent from the footprint record for the site were represented by skeletal fossils and bite marks on bones.     

Corals,molluscs, and paleogeography of late Jurassic strata of the Cerro Pozo Serna,Sonora, Mexico

Jurassic strata of late Oxfordian to early Kimmeridgian age are reported from the Cerro Pozo Serna, northwest-central Sonora, Mexico. The presence of these marine strata greatly alters previous paleogeographic reconstructions of the Tethyan embayment in this area. Approximately 60% of the Sonorian molluscan fauna has been previously reported from Jurassic horizons in the Gulf of Mexico and west Texas regions. The remainder of the molluscs have previously been reported from either the western interior United States or Canada. The Pozo Serna faunas seem to be zoogeographically transitional between communities present in the southern North American Tethyan realm and regions within the central North American Tethyan realm. Additionally, the Pozo Serna fauna greatly resembles contemporaneous communities reported from the Jurassic of Morocco. Corals from the Sonorian Jurassic prove to be, in large part, conspecific with well-known central European and Algerian reef-building species. The scleractinian Lepidophylliopsis gen. nov. and Macgeopsis sonorensis sp. nov. are described from central Sonora.     

New finds of vertebrates in the Middle Devonian Brandenberg Group (Sauerland, Northwest Germany)

Placoderms (Ptyctodontida), acanthodians (incl.Atopacanthus?ambrockensis n. sp.), actinopterygians, dipnoans and crossopterygians — including the first Middle Devonian osteolepids from the Rheinisches Schiefergebirge — are described from the lower Brandenberg Group of Hagen-Ambrock and Lasbeck (northern Sauerland, Northwest Germany). The composition of the fauna is similar to that of contemporaneous Scottish and Baltic Old Red localities, even though typical marine vertebrates are present too (e.g. selachians). This indicates — like the invertebrates — rather a marginal marine deposition.     

A NEW TRISTICHOPTERID (SARCOPTERYGII, TETRAPODOMORPHA) FROM THE UPPER FAMENNIAN EVIEUX FORMATION (UPPER DEVONIAN) OF BELGIUM

Abstract:  Additional material of a large specimen of tristichopterid fish from the Upper Famennian Evieux Formation of Belgium is described. This large fish was previously assigned to Tristichopteridae gen. et sp. indet. due to the lack of diagnostic anatomical data. New available material consists of the internal surface of the parietal shield, vomers and anterior part of the parasphenoid, subopercular and submandibulo-branchiostegal bones, and an internal view of the anterior part of the mandible. A possible autapomorphy of the new form from Belgium, Langlieria socqueti gen. nov. et sp. nov., is the absence of marginal teeth on the vomer except on its most lateral part. Apart from these features, it only differs from the genus Mandageria from Australia in the absence of marginal teeth between the dentary fang and the mandibular symphysis, in the presence of a raised marginal crest lateral to the anterior coronoid fang, and in the presence of numerous small marginal teeth on the premaxilla. It differs from the cosmopolitan genus Eusthenodon in a number of respects: the supratemporal, tabular, and postparietal bones are superficially fused, as are the intertemporal and parietal bones, the dermal ornament is proportionally very fine, and the denticulated field of the parasphenoid stands proud rather than being recessed into the body of the bone.     

Skeletal development of the direct-developing caecilian <Emphasis Type="Italic">Gegeneophis ramaswamii</Emphasis> (Amphibia: Gymnophiona: Caeciliidae)

A few previous studies of skeletal and especially skull development in Gymnophiona often provided contradictory results. We studied the development of the skull and vertebral column of Gegeneophis ramaswamii, a direct-developing Indian caeciliid, based on 13 specimens. The chondrocranium forms at (Brauer in Zool Jahrb Anat 12:477-508,1899) stage 38. First dermal and perichondral ossifications occur at stage 40. The first dermal bones to form are the mentomeckelian, dentary, angular, vomer, and premaxillary. These are followed by the coronoid, palatine, pterygoid, maxillary, and the skull-roofing bones. The last occurring dermal ossifications are the parasphenoid and the squamosal. We present evidence for the occurrence of a lacrimal bone. No ectopterygoid, basioccipital, supraoccipital, pleurosphenoid, postorbital, or supratemporal elements were found. We assess the homology of the bones constituting the caecilian skull and discuss the above-mentioned terminologies. The phylogenetic implications of our findings are briefly discussed and we conclude that the evidence from developmental morphology is at present consistent with a monophyletic Lissamphibia of temnospondyl origin.     

Partial skeleton of Dracopelta zbyszewskii N. Gen. And N. SP., an ankylosaurian dinosaur from the Upper Jurassic of Portugal

The holotype of the nodosaurid ankylosaur Dracopelta zbyszewskii n. gen. and n. sp. is described from the Kimmeridgian(Upper Jurassic) of Ribomar on the west coast of Portugal. This is the first Upper Jurassic ankylosaur to be described that is represented by articulated bones. The specimen consists of a partial rib cage with thirteen dorsal vertebrae and five different types of dermal armor, two of wich show a partial overlap between adjacent plates.     

Remnant Woven Bone and Calcified Cartilage in Mouse Bone: Differences between Ages/Sex and Effects on Bone Strength

IntroductionMouse models are used frequently to study effects of bone diseases and genetic determinates of bone strength. Murine bones have an intracortical band of woven bone that is not present in human bones. This band is not obvious under brightfield imaging and not typically analyzed. Due to the band’s morphology and location it has been theorized to be remnant bone from early in life. Furthermore, lamellar and woven bone are well known to have differing mechanical strengths. The purpose of this study was to determine (i) if the band is from early life and (ii) if the woven bone or calcified cartilage contained within the band affect whole bone strength.

Woven Bone Origin Studies

In twelve to fourteen week old mice, doxycycline was used to label bone formed prior to 3 weeks old. Doxycycline labeling and woven bone patterns on contralateral femora matched well and encompassed an almost identical cross-sectional area. Also, we highlight for the first time in mice the presence of calcified cartilage exclusively within the band. However, calcified cartilage could not be identified on high resolution cone-beam microCT scans when examined visually or by thresholding methods.

Mechanical Strength Studies

Subsequently, three-point bending was used to analyze the effects of woven bone and calcified cartilage on whole bone mechanics in a cohort of male and female six and 13 week old Balb/C mice. Three-point bending outcomes were correlated with structural and compositional measures using multivariate linear regression. Woven bone composed a higher percent of young bones than older bones. However, calcified cartilage in older bones was twice that of younger bones, which was similar when normalized by area. Area and/or tissue mineral density accounted for >75% of variation for most strength outcomes. Percent calcified cartilage added significant predictive power to maximal force and bending stress. Calcified cartilage and woven bone could have more influence in genetic models where calcified cartilage percent is double our highest value.     

A New Species of Goniopholis from the Upper Jurassic of Portugal

The new goniopholidid crocodile Goniopholis baryglyphaeus sp. nov. from the Kimmeridgian of Guimarota/Leiria, Portugal is based on the oldest known relatively complete skeleton of Goniopholis from Europe and consists of a nearly complete skull together with a mandible and various postcranial remains. G. baryglyphaeus shows characters that hitherto have only been described for Goniopholis simus : a caudal expansion of the prefrontal that excludes the frontal from the medial margin of the orbit; and the loss of contact between the paroccipital process and the lateral surface of the squamosal and the quadrate, which exposes the cranioquadrate canal laterally. This new species can be distinguished from other European Goniopholis species by an articular facet placed ventral to the retroarticular process, and directed slightly medioventrally; a caudal margin of the mandible forming almost a right angle at its caudoventral corner; an almost square rostrolateral corner of the cranial table; a straight transverse suture between the parietal and the frontal with a median rostral process; a rostrally tapering wedge-like lacrimal, and a regular heavy skull-sculpturing. The new find of Goniopholis in Portugal shows that this genus was distributed in a larger area, and was present much earlier, than hitherto reported in south-western Europe.     

Anatomical study of the skull of amphisbaenian Diplometopon zarudnyi (Squamata,Amphisbaenia)

This study investigates the amphisbaenian species skull which includes cranium, lower jaw and hyoid apparatus. The medial dorsal bones comprise the premaxilla, nasal, frontal and parietal. The premaxilla carries a large medial tooth and two lateral ones. The nasals are paired bones and separated by longitudinal suture. Bones of circumorbital series are frontal, orbitosphenoid and maxilla. The occipital ring consists of basioccipital, supraoccipital and exooccipital. Supraoccipital and basioccipital are single bones while the exo-occipitals are paired. The bones of the palate comprise premaxilla, maxilla, septomaxilla, palatine, pterygoid, ectopterygoid, basisphenoid, parasphenoid, orbitosphenoid and laterosphenoid. Prevomer and pterygoid teeth are absent. Palatine represent by two separate bones. The temporal bones are clearly visible. The lower jaw consists of the dentary, articular, coronoid, supra-angular, angular and splenial. The hyoid apparatus is represented by a Y-shaped structure. The mandible is long and is suspended from the braincase via relatively short quadrate. There is an extensive contact between the long angular and the large triangular coronoid. Thus inter-mandibular joint is bridged completely by the angular and consequently, the lower jaws are relatively rigid and kinetic. The maxillae are suspended from the braincase largely by ligaments and muscles rather than through bony articulation. In conclusion, the skull shape affects feeding strategy in Diplometopon zarudnyi. The prey is ingested and transported via a rapid maxillary raking mechanism.     

The ontogeny of bone growth in two species of dormice: Reconstructing life history traits

Though bone histology has become a powerful tool to reconstruct life history strategies and physiology in living and extinct reptiles and amphibians, it is of limited use in mammals. Dormice (Myoxidae) are good candidates for assessing the relation between bone microstructure and life history due to their long life span, marked physiological cycles and negligible bone remodelling. We carried out the most comprehensive study so far analyzing 16 wild individuals of unknown age belonging to two different species of dormice, Glis glis and Eliomys quercinus. Our study shows a high degree of consistency in the number of resting lines present in bones of the same individual, with femora providing the most accurate age estimations. Moreover, the presence of a single LAG in some juveniles allows discerning between offspring from different reproductive events (early or late litters).     

Itatodon tatarinovi (Tegotheriidae, Mammalia), a docodont from the Middle Jurassic of Western Siberia and phylogenetic analysis of Docodonta

Itatodon tatarinovi Lopatin et Averianov, 2005 is represented by two lower molars and a lower molar fragment from the upper part of the Itat Formation (Bathonian Stage) of the Berezovskii quarry (southern Krasnoyarsk Region). Based on the presence of a pseudotalonid, bordered by the crests a-b, b-e, e-g, and a-g, Itatodon is assigned to the endemic Asian family Tegotheriidae. In this genus, the crest a-b is reduced and the thick lingual cingulid is better developed than that of other docodonts. Phylogenetic analysis of Docodonta shows paraphyly of Morganucodonta relative to docodonts and independent development of the pseudotalonid in the Tegotheriidae and the clade comprising Krusatodon, Castorocauda, Cyrtlatherium, and Dsungarodon.     

Pecularities of bony skeleton development in Asian clawed salamanders (Onychodactylus, Hynobiidae) related to embryonization

We studied skull, vertebral column, and limb skeleton development in Japanese clawed salamander Onychodactylus japonicus (Hynobiidae). The study is based on the ontogenetic series of embryos and larvae obtained from wild-captured adults by artificial induction of breeding using hormonal stimulation. The first stages of the skeleton formation in O. japonicus are shifted to the late embryonic period and hatching larvae already possess a well-ossified vertebral column, large number of skull ossifications and show signs of ossification in the forelimb skeleton. Compared to the primitive pattern of the skeleton development typical for other hynobiid salamanders, O. japonicus shows a number of heterochronies related to embryonization. In particular, this species is characterized by an earlier ossification of the vertebral column compared to that of the skull and by the delayed development and early reduction of the coronoid. Our results, along with the previously reported data on the skeleton development in the Fischer’s clawed salamander O. fischeri (Smirnov and Vassilieva, 2002), indicate that the genus Onychodactylus is characterized by the loss or reduction of several skeletal features typically found at early larval stages in other Hynobiidae species. In particular, provisional bones (especially the coronoid) and their dentition are underdeveloped. In addition, it is corroborated that the first tooth generation is absent in Onychodactylus, whereas such monocuspid nonpedicellate tooth generation normally develops at the early larval stages of other caudate amphibians. Since similar patterns of skeleton ontogeny are observed in other caudate groups with different extent of embryonization, it is proposed that, in different lineages of Urodela, the evolution of ontogeny followed similar pathways and was accompanied by the same changes in skeletogenesis.     

Une espèce nouvelle du Kimméridgien du Portugal (Estremadura): Aulacomyella abadiensis nov. sp. (Bivalvia,Posidoniidae)

The Kimmeridgian Series situated at the North ofLisbon is included in the Portuguese Lusitanian basin. Its sandy clays pelagic facies with planctonic foraminifera contains a new species of bivalvia: Aulacomyella abadiensis related to A. neogeaeImlay from the Middle Kimmeridgian of Mexico and from the Kimmeridgian of Crimea. This species confirms the Middle Kimmeridgian.