the northern Hemisphere dominates our knowledge of Mesozoic and cenozoic fossilized tree resin (amber) with few findings from the high southern paleolatitudes of Southern Pangea and Southern Gondwana. Here we report new Pangean and Gondwana amber occurrences dating from ~230 to 40 Ma from Australia (Late triassic and paleogene of tasmania; Late cretaceous Gippsland Basin in Victoria; Paleocene and late middle Eocene of Victoria) and New Zealand (Late Cretaceous Chatham Islands). The Paleogene, richly fossiliferous deposits contain significant and diverse inclusions of arthropods, plants and fungi. These austral discoveries open six new windows to different but crucial intervals of the Mesozoic and early cenozoic, providing the earliest occurrence(s) of some taxa in the modern fauna and flora giving new insights into the ecology and evolution of polar and subpolar terrestrial ecosystems. Amber, or ancient tree resin, is valued most highly in science as an exceptional preservation medium for small organisms as fossil bioinclusions. In paleontology, diverse animals, plants and microorganisms have the potential of being preserved in three dimensions in the finest of detail. Worldwide, ambers have been recorded dominantly in upper Mesozoic to lower Cenozoic rocks from Northern Hemisphere and Northern Gondwana localities, but only one southern high latitude occurrence of microorganisms and microbe-like inclusions in amber has been published from the early Late Cretaceous (Turonian) in the Flaxman and Waarre formations of southern Victoria, Australia 1. Other Late Cretaceous ambers have recently been reported from the Chatham Islands, New Zealand 2 , representing internal plant resin canals (no exuded amber), and small to minute amber fragments have been reported from the early Paleogene (early Eocene) of western Tasmania 3 , mid-Paleogene of Victoria 4 and strandline deposits of the southern coast of Australia from Victoria to the west coast 5 (Fig. 1). However, no preserved animals or plants have yet been found. Neogene ambers have been reported from the Mio-Pliocene Australian Latrobe Valley Coal, cropping out near Yallourn, Allendale and also Lal Lal in Victoria in Australia 6,7 (Fig. 1). Earlier reports of Cretaceous amber sourced from the Wonthaggi Coal Mine 7 have proved to be anomalous and not from the Mesozoic or early Cenozoic 1. Amber from Cape York, far northern Queensland, Australia, is under study to establish if it is autochthonous or allochthonous (see discussion in Supplementary Text). New

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Mandibular force profiles apply the principles of beam theory to identify mandibular biomechanical properties that reflect the bite force and feeding strategies of extant and extinct predators. While this method uses the external dimensions of the mandibular corpus to determine its biomechanical properties, more accurate results could potentially be obtained by quantifying its internal cortical bone distribution. To test this possibility, mandibular force profiles were calculated using both external mandibular dimensions ('solid mandible model') and quantification of internal bone distribution of the mandibular corpus obtained from computed tomography scans ('hollow mandible model') for five carnivorans (Canis lupus, Crocuta crocuta, Panthera leo, Neofelis nebulosa and the extinct Canis dirus).Comparison reveals that the solid model slightly overestimates mandibular biomechanical properties, but the pattern of change in biomechanical properties along the mandible remains the same. As such, feeding behavior reconstructions are consistent between the two models and are not improved by computed tomography. Bite force estimates produced by the two models are similar, except in C. crocuta, where the solid model underestimates bite force by 10-14%. This discrepancy is due to the more solid nature of the C. crocuta mandible relative to other carnivorans. Therefore, computed tomography improves bite force estimation accuracy for taxa with thicker mandibular corpora, but not significantly so otherwise. Bite force estimates derived from mandibular force profiles are far closer to empirically measured bite force than those inferred from jaw musculature dimension. Consequently, bite force estimates derived from this method can be used to calibrate finite-element analysis models.

Dinosaur tracksites recently discovered in exposures of the Belly River Group in the Milk River Natural Area (MRNA) and Dinosaur Provincial Park (DPP) of southern Alberta represent a novel type of ichnofossils. The tracks, all referable to hadrosaurs, occur as sideritic or calcareous concretions protruding above fine-grained deposits and are here termed concretionary tracks. Detailed sedimentological, petrographic, and geochemical analyses reveal that, although the MRNA and DPP tracks are of different mineralogical compositions (calcium carbonate versus siderite, respectively), they display similar internal structures (microscopic convoluted laminations) and occur in depositional settings indicative of wet paleoenvironments, where the ground was soft and water saturated. These characteristics suggest that concretionary tracks are footprint casts that formed as groundwater rich in dissolved carbonates flooded depressions left in the soft substrate. As the ponded water evaporated, minerals began to precipitate and mix with clastic material transported into the depressions, settling as finely laminated mud within the tracks and filling them either completely or partially. The geochemical composition of the precipitate would depend on the prevalent groundwater conditions (e.g., pH, dissolved carbonate and sulphate concrentrations). Cementation of the tracks occurred relatively soon after burial (<100 years), possibly in response to microbial activity and saturation by mineral-rich groundwater, and modern erosion exposed the concretionary tracks by removing the softer host unit. Recognition of this novel type of ichnofossils suggests dinosaur tracks may be more common than previously thought. Unfortunately, concretionary tracks tend to break apart rapidly when the encasing and underlying substrate erodes away, altering their diagnostic shape and rendering them indistinguishable from nonichnogenic concretions. As such, concretionary tracks may be transient ichnofossils in the badlands, explaining why they are rarely recognized. Résumé :Des sites préservant des empreintes de pas de dinosaures récemment découverts dans des affleurements du Groupe de Belly River dans la Milk River Natural Area (MRNA) et dans le Dinosaur Provincial Park (DPP) du sud de l'Alberta représentent un nouveau type d'ichnofossiles. Les empreintes, qui ont toutes été produites par des hadrosaures, sont préservées sous forme de concrétions sidéritiques ou calcaires émergeant de dépôts fins et sont ici nommées « empreintes concrétionnaires ». Des analyses sédimen-tologiques, pétrographiques et géochimiques détaillées révèlent que, bien que les empreintes de la MRNA et du DPP soient de compositions minéralogiques différentes (carbonate de calcium et sidérite, respectivement), elles possèdent des structures internes semblables (lamination convolutée microscopique) et se trouvent dans des milieux de dépôt qui reflètent des paléoenvironnements humides où le sol était mou et saturé en eau. Ces caractéristiques suggèrent ou indiquent que les tra...

A new Turonian amber occurrence, representing the oldest in situ amber locality in Australia and the southern-most locality in Gondwana, has recently been discovered in the Otway Basin of Victoria. The amber was collected from petroleum cores and many pieces contain a range of inclusions that can provide information on the depositional history of the resin. To date, one species of fern spore (Cyathidites minor) and one species of lycophyte spore (Kraeuselisporites sp?) have been conclusively identified in the amber, along with filamentous microorganisms and degraded plant matter. Several samples are also rife with pseudoinclusions as reported recently in other ambers. The abundance of preserved particulate debris and wind dispersed spores suggest that the Otway amber formed subaerially. Furthermore, based on the range of bioinclusions and forms of pseudoinclusions preserved within a single piece of amber, the locus of hardening for individual samples is variably interpreted as occurring in the tree tops, on the tree trunk or on the ground surface. Notably, specific inclusion assemblages are associated with certain colours of amber. By extension, and in accordance with recent studies, amber colour may be indicative of depositional environment. Variation in the environment of solidification may, therefore, be sufficient to account for the broad range of morphological characteristics preserved in a single amber deposit.