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We report new ichnites corresponding to a trackway composed of three tetradactyl pedal footprints and plant remains near Southeastern Guatacondo, Tarapacá Region, within the transition of Majala and Chacarilla Formations (Late Jurassic-Early Cretaceous). The fossils were found in the context of a Copper Mining road construction at the PK23 site, Quebrada Blanca Phase 2 project, by the Teck Mining Company Quebrada Blanca S.A. We performed stratigraphical, paleobotanical, and paleoichnological studies, along with the footprint characterization and comparisons by Principal Component Analysis, and Discriminant Analysis of I-II, II-III and III-IV interdigital angles, using a large tetradactyl footprint morphological database of potential producers (dinosaurs, crocodiles, lepidosaurs, and pterosaurs). Additionally, we performed 3D pedal computer modeling kinematic analysis of the Chilesaurus diegosuarez i's 3D tetradactyl foot under two different sedimentary conditions (i.e. hard soil with superficial impression, and soft sediment with a penetrative impression), to test it as a potential trackmaker. The stratigraphic section reveals an association of siliciclastic facies, formed by the intercalation of fine-grained sandstones and wackes, with ripple marks, cross and horizontal lamination, evidencing intermittent moderate to low sedimentation energy. Among the plant material, several organs of the family Cheirolepidiaceae were identified such as, leaves and leafy branches of Brachyphyllum type, Classostrobus pollen cone, ovuliferous scales, and wood fragments related to Cupressinoxylon. The monodominance of Cheirolepidiaceae among the preserved macroflora allows inferring the characteristics of the environment in which the plants lived, highlighting halophytic, and temporarily arid conditions. Evidence as a whole, permits to interpret the depositional environment as an arid deltaic-littoral plain, temporarily covered with an ephemeral water layer associated with a stunted woody vegetation, in which terrestrial vertebrates walked by. Despite the low predictive power of the multivariate analysis, due to the various sources of morphological variability inherent to footprint formation, the PK23 footprints seem to better correspond to Dinosauria or Avialae as the most likely producers, rather than to Lepidosauria or Crocodylia, discarding the dinosaur Chilesaurus due to very low interdigital mediolateral rotation capabilities. • We studied a palaeobotanical and paleoichnological record exposed during the construction of a road leading to a copper mine. • Majala is the most likely bearing Formation. Its depositional environment is interpreted as an arid deltaic-littoral plain. • Different plant organs identified are all attributables to the Cheirolipidiaceae Family. • We performed multivaried analyses on an extensive tetradactyl footprint interdigital angle database. • We built a 3D kinematic model of Chilesaurus foot in order to compare it as a potential producer • PK23 footprintsbetter correspond to Dinosauria or Avialae as the most likely producer, but is distinct from Chilesauridae. [ABSTRACT FROM AUTHOR]

Punta Pelluco is a known fossil forest locality near Puerto Montt in the province of Llanquihue, Southern Chile, which preserves exquisite palynological and xylological records of the last glacial period (Late Pleistocene), discoveries that have been made since 1978. The present investigation contributes the first Chilean record of camelid and proboscidean footprints, discovered in 2015 at Punta Pelluco. The ichnospecies identified are Lamaichnum guanicoe (average footprint 10.1 cm length, 9.9 cm width) and the largest Proboscipeda cf. P. australis (average 38 cm length, 38.2 cm width in the first footprint and average 41.8 cm length, 42.2 cm width in the second footprint) found in South America, respectively. These are the oldest Chilean records for Lamini and Proboscidea, dating back to between about 52.300 and 44.300 years ago. Not much is known about the dispersal of camelids and gomphotherids through the Andean Mountains after the Great American Biotic Interchange, but the present record status seems to indicate that the presence was restricted to the Pleistocene, at least 44,000 years ago. [ABSTRACT FROM AUTHOR]

The Miocene Caragua fossil fauna in northern Chile contains a considerable number (7) of articulated partial skeletons tentatively assigned to Caraguatypotherium munozi (Notoungulata, Mesotheriidae), which presents up to 40% body size difference. Since either inter- and intra- specific wide size range has been observed in the Mesotheriidae family in general, we wanted explore the ontogenic stage signature of the sample, by carrying out the first comprehensive paleohistological description of the appendicular system in Notoungulata. Results show that: 1) they can be classified as subadults and adults, based on the presence of bone tissues typical of ceased somatic growth; 2) there is a notorious inter-skeletal variation on bone growth rates (skeletal modularity), particularly, the humerus showed a slower diameter growth and less remodelling than the femur, resulting as a better element for ontogenetic analyses; 3) marked cyclical growth is observed, characterised by fast early ontogenic continuous growth, and subsequent fast/slow stratified bone tissue layering. In general, such growth pattern suggests that C. munozi had a similar ontogenetic growth process as other modern mammals, that it should also be influenced by other sex-related, ecological and environmental factors. Likely related to the presence of rapid climatic variations, due to orogenic uplift and concomitant re-organization of the drainage processes along the western tectonic front of the Central Andes at that time., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Campos-Medina et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The present study describes the discovery of a singular sedimentary structure corresponding to an ichnite that was excavated at the paleo-archaeological site Pilauco (Osorno, Chile). The trace fossil is associated with megafauna bones, plant material and unifacial lithic tools. Here we present a detailed analysis of the Pilauco ichnite and associated sedimentary structures, as well as new radiocarbon data. The ichnological analysis confidently assigns the trace to the ichnospecies Hominipes modernus-a hominoid footprint usually related to Homo sapiens. Some particular characteristics of the Pilauco trace include an elongated distal hallux, lateral digit impressions obliterated by the collapsed sediment, and sediment lumps inside and around the trace. In order to evaluate the origin of the ichnite, trackmaking experiments are performed on re-hydrated fossil bed sediments. The results demonstrate that a human agent could easily generate a footprint morphology equivalent to the sedimentary structure when walking on a saturated substrate. Based on the evidence, we conclude that the trackmaker might well have been a bare-footed adult human. This finding, along with the presence of lithic artifacts in the same sedimentary levels, might represent further evidence for a pre-Clovis South American colonization of northern Patagonia, as originally proposed for the nearby Monte Verde site., Competing Interests: The authors have declared that no competing interests exist.