Cambaytherium, Nakusia, and Kalitherium are closely related early Eocene mammals from the Indo-Pakistan region that have been assigned to Perissodactyla (Laurasiatheria) or Anthracobunidae. The latter have been variously considered artiodactyls or perissodactyls, but more recently are usually placed at the base of the order Proboscidea or of the more inclusive Tethytheria (Afrotheria). We present new evidence from the dentition, skull, and postcranial skeleton of Cambaytherium, from Gujarat, India (ca. 54.5 Ma), that cambaytheres occupy a pivotal position as the sister taxon of Perissodactyla. Cambaytherium was more robust than basal perissodactyls such as ″Hyracotherium″ and Homogalax, and had a body mass of ~25-27 kg based on humeral, radial, and dental regressions. Perissodactyl synapomorphies include a transverse nasal-frontal suture, twinned molar metaconids, and an astragalus with deeply grooved trochlea and a saddleshaped navicular facet. Like perissodactyls, cambaytheres are mesaxonic and have hooflike unguals and a cursorially-adapted skeleton. Plesiomorphic traits compared to basal perissodactyls include bunodont molars with large conules and almost no hint of bilophodonty, unmolarized premolars, sacrum with four vertebrae, humerus with distally extensive pectoral crest and distal articulation lacking a capitular tail, distal radius without discrete scaphoid and lunate fossae, femur with low greater trochanter, calcaneus robust and wide with rounded ectal facet, astragalus wide with moderately long neck and vestigial astragalar foramen, navicular and cuboid short and wide, metapodials short and robust, and Mc I and Mt V present. In most or all of these traits cambaytheres are intermediate between phenacodontid condylarths and perissodactyls but closer to the latter. Our phylogenetic analyses place cambaytheres just outside perissodactyls, and place anthracobunids among primitive perissodactyls. However, similarities between cambaytheres and anthracobunids suggest that they are closely related, and future discovery of skeletal material of anthracobunids will provide a test of this hypothesis. Our results indicate that Anthracobunidae are not Proboscidea or tethytheres, and suggest that the origin of Perissodactyla may have taken place on the drifting Indian plate. How the progenitors of perissodactyls reached India is more problematic but might have involved land connections with Afro-Arabia during the Paleocene. Field work and research supported by the National Geographic Society.
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The intentional combination of two or more marine activities with the purpose of sharing space, infrastructure, resources and/or operations, referred to as multiuse, is gaining attention as a means to reduce the spatial footprint of human activities but possibly also its ecological footprint. In this study, the Spatial Cumulative Assessment of Impact Risk for Management (SCAIRM) method was adapted and applied to assess whether multi-use can reduce the ecological footprint in terms of the cumulative impacts on the marine ecosystem, by integrating multiple offshore activities in different configurations as compared to these activities separated in space, referred to as single-use. These configurations combine renewable energy, aquaculture, nature restoration and tourism activities, in different combinations. For the sake of this multi-use assessment these activities were subdivided into actions, their allocation in space and time represented in scenarios (e.g. single-use versus multi-use) which were then evaluated in terms of their ecological footprint (i.e. Impact Risk). The main finding is that the calculated Impact Risk in multi-use is often lower than that in single-use and in any case never higher. This study also shows that there is still much to be gained in terms of further reduction in Impact Risk through an optimization of the multi-use design by comparing the scenario based on actual pilots deemed more realistic (i.e. co-existence with limited synergies) with a hypothetical optimal scenario (i.e. multi-functional).
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RBINS Staff Publications 2024
