More Like this

1. A virtual repository of Lower Siwalik Miocene fossils from Ramnagar (Udhampur District, Jammu & Kashmir), India.

   Patel, B.A.; Gilbert, C.C.; Sehgal, R.K.; Singh, N.P.; Di, A.; Choudhary, D.; Wazir, W.A.; Campisano, C.J.; Patnaik, R. (March 2022, American journal of physical anthropology)

   Vertebrate fossils have been known from Lower Siwalik Miocene deposits surrounding the town of Ramnagar (Udhampur District, Jammu & Kashmir) in northwest India since Barnum Brown’s American Museum of Natural History (AMNH) expedition in 1922. These fossils included dentognathic specimens of Sivapithecus and other Chinji Formation-aged mammals. Paleontological fieldwork has continued sporadically in the Ramnagar region ever since, and in that time, a large number of vertebrate fossils have been recovered by many different researchers and institutions, including the recently discovered primates Kapi and Ramadapis. Ramnagar fossils are currently housed in several institutions across India and the United States, thereby making it challenging to comprehensively study the entire collection. Consequently, a full understanding of important questions related to the taxonomy, paleobiology, paleoecology, and biochronology of the Ramnagar fauna cannot be readily obtained. Moreover, without answers to these questions, correlations and comparisons cannot be accurately made to other similar aged fossil localities in the Siwaliks (i.e., Potwar Plateau, Pakistan) and elsewhere in Eurasia. Therefore, the goal of this collaborative project is to establish and grow a 3D digital repository of all fossil specimens from the Ramnagar region for continued comprehensive study. We employ µCT, surface scanning, and photogrammetry to virtually bring together specimens from the AMNH, Panjab University, Wadia Institute of Himalayan Geology, and Yale Peabody Museum. Thus far, >100 specimens have been digitized and made openly accessible on the MorphoSource web platform. Here we highlight some of the best-preserved specimens, including recovered primates and micromammals, and discuss their scientific importance. 

   more » « less
2. A virtual repository of Lower Siwalik Miocene fossils from Ramnagar (Udhampur District Jammu & Kashmir), India.

   Patel, B.A. (January 2022, American journal of physical anthropology)

   Vertebrate fossils have been known from Lower Siwalik Miocene deposits surrounding the town of Ramnagar (Udhampur District, Jammu & Kashmir) in northwest India since Barnum Brown’s American Museum of Natural History (AMNH) expedition in 1922. These fossils included dentognathic specimens of Sivapithecus and other Chinji Formation-aged mammals. Paleontological fieldwork has continued sporadically in the Ramnagar region ever since, and in that time, a large number of vertebrate fossils have been recovered by many different researchers and institutions, including the recently discovered primates Kapi and Ramadapis. Ramnagar fossils are currently housed in several institutions across India and the United States, thereby making it challenging to comprehensively study the entire collection. Consequently, a full understanding of important questions related to the taxonomy, paleobiology, paleoecology, and biochronology of the Ramnagar fauna cannot be readily obtained. Moreover, without answers to these questions, correlations and comparisons cannot be accurately made to other similar aged fossil localities in the Siwaliks (i.e., Potwar Plateau, Pakistan) and elsewhere in Eurasia. Therefore, the goal of this collaborative project is to establish and grow a 3D digital repository of all fossil specimens from the Ramnagar region for continued comprehensive study. We employ µCT, surface scanning, and photogrammetry to virtually bring together specimens from the AMNH, Panjab University, Wadia Institute of Himalayan Geology, and Yale Peabody Museum. Thus far, >100 specimens have been digitized and made openly accessible on the MorphoSource web platform. Here we highlight some of the best-preserved specimens, including recovered primates and micromammals, and discuss their scientific importance. Funding generously provided by the U.S. National Science Foundation (BCS-1945618, BCS-1945736, BCS-1945743) and the Leakey Foundation. 

   more » « less
3. Inaccurate fossil placement does not compromise tip‐dated divergence times

   https://doi.org/10.1111/pala.12680  

   Mongiardino_Koch, Nicolás; Garwood, Russell_J; Parry, Luke_A (November 2023, Palaeontology)

   Abstract Time‐scaled phylogenies underpin the interrogation of evolutionary processes across deep timescales, as well as attempts to link these to Earth's history. By inferring the placement of fossils and using their ages as temporal constraints, tip dating under the fossilized birth–death (FBD) process provides a coherent prior on divergence times. At the same time, it also links topological and temporal accuracy, as incorrectly placed fossil terminals should misinform divergence times. This could pose serious issues for obtaining accurate node ages, yet the interaction between topological and temporal error has not been thoroughly explored. We simulate phylogenies and associated morphological datasets using methodologies that incorporate evolution under selection, and are benchmarked against empirical datasets. We find that datasets of 300 characters and realistic levels of missing data generally succeed in inferring the correct placement of fossils on a constrained extant backbone topology, and that true node ages are usually contained within Bayesian posterior distributions. While increased fossil sampling improves the accuracy of inferred ages, topological and temporal errors do not seem to be linked: analyses in which fossils resolve less accurately do not exhibit elevated errors in node age estimates. At the same time, inferred divergence times are biased, probably due to a mismatch between the FBD prior and the shape of our simulated trees. While these results are encouraging, suggesting that even fossils with uncertain affinities can provide useful temporal information, they also emphasize that palaeontological information cannot overturn discrepancies between model priors and the true diversification history. 

   more » « less
4. Fossil preparation in Kenya

   Kioko, Mitchelle W; Cote, Susanne; Ndiema, Emmanuel (July 2024, Eastern African Association of Palaeoanthropology and Palaeontology)

   Fossil preparation is a crucial component in the preservation and study of fossils. The role of fossil preparators encompasses the intricate tasks of identifying, preparing, and cleaning fossils specimens, including delicate fossils like micro-mammals, apes, birds, and hominin. This presentation explores the journey of a Kenyan woman trying to fit into this professional field, which has traditionally been dominated by men. The preparator has principally worked at a Miocene site located in Nyanza- Kenya called Tonde Bridge, that dates to ~23Ma. Her work includes hardening of the fossils, plastering, and fossil exhumation in the field. She has mainly focused on the fossil teeth of hominoids, carnivores, and elephant bones, using an air scribe. She has also been involved in other subsequent fossils preparation in paleo- lab National Museums of Kenya. This presentation sheds light on the role of fossil preparators in inspiring a new generation of women in the paleo-sciences. 

   more » « less
5. Paleoenvironments, taphonomy, and stable isotopic content of the terrestrial, fossil-vertebrate–bearing sequence of the El Disecado Member, El Gallo Formation, Upper Cretaceous, Baja California, México

   https://doi.org/10.1130/GES02207.1  

   Fastovsky, David E.; Montellano-Ballesteros, Marisol; Fricke, Henry C.; Ramezani, Jahandar; Tsukui, Kaori; Wilson, Gregory P.; Hall, Paul; Hernandez-Rivera, Rene; Alvarez, Geraldo (June 2020, Geosphere)

   null (Ed.)

   Abstract The Late Campanian (Late Cretaceous), upper part of the El Disecado Member, El Gallo Formation, Baja California, México, preserves a rich fossil assemblage of microvertebrates and macrovertebrates, silicified logs, macroscopic plant remains, and pollen that was likely deposited as the distal part of a subaerial fan. The unit was episodic and high energy, with its salient features deriving from active river channels and sheet, debris-flow deposits. Landscape stability is indicated by the presence of compound paleosol horizons, containing Fe2O3 mottling in B horizons, cutans, and calcium carbonate concretions. All of these features indicate wet/dry cyclicity in subsurface horizons, likely attributable to such cyclicity in the climate. Drainage was largely to the north and to a lesser extent, the west; however, some current flow to the south and east is preserved which, in conjunction with the proximal location of marginal marine deposits, suggest the influence of tides in this setting. The fossil vertebrates preserved in this part of the El Disecado Member are almost exclusively allochthonous, preserved as disarticulated isolated clasts in hydraulic equivalence in the braided fluvial system. A relatively diverse microvertebrate assemblage is preserved, the largest components of which are first, dinosaurs, and second, turtles. Non-tetrapod fossils are relatively uncommon, perhaps reflecting an absence of permanent standing water in this depositional setting. Here we report a high-precision U-Pb date of 74.706 + 0.028 Ma (2σ internal uncertainty), obtained from zircons in an airfall tuff. The tuff is located low within the sequence studied; therefore, most of the sedimentology and fossils reported here are slightly younger. This date, which improves upon previously published 40Ar/39Ar geochronology, ultimately allows for comparison of these El Gallo faunas and environments with coeval ones globally. Primary stable isotopic nodules associated with roots in the paleosols of the terrestrial portion of the El Disecado Member are compared with ratios from similar sources from coeval northern and eastern localities in North America. Distinctive latitudinal gradients are observed in both δ13C and δ18O, reflecting the unique southern and western, coastal geographic position of this locality. These differences are best explained by differences in the floras that populated the northern and eastern localities, relative to the southern and western floras reported here. 

   more » « less