Desert Mammals Disappeared at the Dawn of the Holocene Quaternary From Ethiopia

Paleoenvironmental and biogeographic implications of terminal Pleistocene large mammals from the Ziway–Shala Basin, Main Ethiopian Rift, Ethiopia

Authors:

Lesur et al

Abstract:

The terminal Pleistocene is a period of profound climatic and environmental change in Africa, with paleoenvironmental records documenting tremendous regional variation. Environmental records needed to understand these dynamics are currently lacking from the Horn of Africa. Here we provide a new paleoenvironmental record based of new faunal data from archeological sites along the Bulbula River (Ziway–Shala Basin, Main Ethiopian Rift) in Ethiopia. Research conducted in this area has uncovered archeological assemblages that document various phases of the Late Pleistocene and Early Holocene. Two sites dated to the terminal Pleistocene are considered here, B1s1 and B1s4. The former includes a very large assemblage of more than 20,000 skeletal remains. Both faunal assemblages are dominated by bovids of the tribes Alcelaphini and Antilopini and include Damaliscus hypsodon, a small extinct alcelaphine. The faunal remains from these sites, like those from the contemporary site of Lukenya Hill in south-central Kenya, are indicative of widespread arid grasslands. Several ungulates are found outside of their historic ranges, including Grant's gazelle (Nanger granti) and Dorcas gazelle (Gazella dorcas). Their absence from the region today likely reflects a combination of paleoenvironmental change since the end of the Pleistocene coupled with more recent human impacts. The combination of archeological and faunal data suggests that B1s1 could have been a residential site with seasonal occupation to acquire raw material from local obsidian sources and to hunt bovids in the arid plain, including species that ultimately disappear or shift their range at the onset of the Holocene with the return of warmer and moister conditions.

Ethiopia's Paleoclimate Became Humid, Wetter and Possibly Monsoonal During the Carnian/Norian Triassic

Paleoclimatic records of Late Triassic paleosols from Central Ethiopia

Author:

Dawit

Abstract:

The present study documents the major paleosols types within the Lower Adigrat Sandstone in the Blue Nile Basin of central Ethiopia, with the aim of unraveling the paleoclimatic signatures embedded in them. The paleosols developed within an 80-m-thick siliciclastic succession deposited in a mixed tide- and wave-dominated incised valley estuary during the Late Triassic.

Based on down-profile variations in pedogenic features, three major paleosol types (i.e., types I, II and III) were identified. Type I paleosols dominate the lower part of the section and are interpreted as moderately well-drained argillic Vertisols. The dominant pedogenic process was shrinking and swelling of expandable clays (i.e., smectite) through repeated wetting and drying cycles. The morphologies and the mineralogy of the paleosols provide persuasive evidence for pedogenesis under semi-arid subtropical climatic conditions with pronounced wet-dry seasonality, highly fluctuating soil moisture regime, and deep groundwater table. The presence of a calcic Bk horizon deep in the profiles is consistent with elevated soil moisture deficits and low to moderate mean annual precipitation (MAP). Type II paleosols, interpreted to represent vertic Gleysols, are more common in the middle part of the section. The pervasive gleying reflects poor soil drainage and a shallow groundwater table where the soil is waterlogged most of the year. These paleosols suggest a humid tropical climate characterized by alternating wet-dry seasonality but with more wet months per year. The top of the unit is dominated by type III paleosols that represent gleyed Oxisols, reflecting a more humid equatorial climate marked by wet seasons, elevated annual soil moisture content, and a high water table. The presence of plinthite/laterite is in agreement with a wet equatorial climate characterized by extensive chemical weathering and long periods of landscape stability.

The observed vertical progression in the major paleosol types from Vertsols to Gleysols and Oxisols implies a systematic change in the number of wet months, most probably in response to regional tectonics and long-term climate change. Because the number of wet months is, in part, related to latitude and monsoonal climates, the upward stratigraphic trend in paleosol orders is interpreted to signal the northward or equatorward migration of the Blue Nile Basin and central Ethiopia within Pangea from dry subtropical low-latitudes in the early Late Triassic (Carnian‐Norian) toward the humid, wet equatorial, possibly monsoonal, paleoclimatic zone in the Late Triassic (Norian‐Rhaetian).

Ethiopians Have Several Cardiac Related Genetic Adaptations

Ethiopians have lived at high altitudes for thousands of years, providing a natural experiment for studying human adaptations to low oxygen, a condition known as hypoxia. One factor that may enable Ethiopians to tolerate high altitudes and hypoxia is the endothelin receptor type B (EDNRB) gene. Researchers at University of California, San Diego School of Medicine now find that mice with lower-than-normal levels of EDNRB protein are remarkably tolerant to hypoxia. The study, published this week by the Proceedings of the National Academy of Sciences, provides a mechanism for the gene's role in adaptation to life at high altitudes and suggests that EDNRB could be targeted to treat sea level diseases that stem from lack of oxygen.

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Australopithecus deyiremeda: a new Pliocene Neogene Hominin Living Beside Lucy, A afarensis.

New species from Ethiopia further expands Middle Pliocene hominin diversity

Authors:

Haile-Selassie et al

Abstract:

Middle Pliocene hominin species diversity has been a subject of debate over the past two decades, particularly after the naming of Australopithecus bahrelghazali and Kenyanthropus platyops in addition to the well-known species Australopithecus afarensis. Further analyses continue to support the proposal that several hominin species co-existed during this time period. Here we recognize a new hominin species (Australopithecus deyiremeda sp. nov.) from 3.3–3.5-million-year-old deposits in the Woranso–Mille study area, central Afar, Ethiopia. The new species from Woranso–Mille shows that there were at least two contemporaneous hominin species living in the Afar region of Ethiopia between 3.3 and 3.5 million years ago, and further confirms early hominin taxonomic diversity in eastern Africa during the Middle Pliocene epoch. The morphology of Au. deyiremeda also reinforces concerns related to dentognathic (that is, jaws and teeth) homoplasy in Plio–Pleistocene hominins, and shows that some dentognathic features traditionally associated with Paranthropus and Homo appeared in the fossil record earlier than previously thought.

Something is wrong in the world: a paleoanthropologist is using cladistics... also comes with an odd tree!  At least compared to the traditional ones.  Interesting that A sediba is not included.

Ardipithecus Teeth Found in Miocene Neogene Ethiopia?

Late Miocene hominin teeth from the Gona Paleoanthropological Research Project area, Afar, Ethiopia

Authors:

Simpson et al

Abstract:

Since 2000, significant collections of Latest Miocene hominin fossils have been recovered from Chad, Kenya, and Ethiopia. These fossils have provided a better understanding of earliest hominin biology and context. Here, we describe five hominin teeth from two periods (ca. 5.4 Million-years-ago and ca. 6.3 Ma) that were recovered from the Adu-Asa Formation in the Gona Paleoanthropological Research Project area in the Afar, Ethiopia that we assign to either Hominina, gen. et sp. indet. or Ardipithecus kadabba. These specimens are compared with extant African ape and other Latest Miocene and Early Pliocene hominin teeth. The derived morphology of the large, non-sectorial maxillary canine and mandibular third premolar links them with later hominins and they are phenetically distinguishable and thus phyletically distinct from extant apes.

More Evidence From Ethiopia Suggesting Something Strange Happened During the Late Cryogenian NeoProterozoic

Stratigraphy and geochronology of the Tambien Group, Ethiopia: Evidence for globally synchronous carbon isotope change in the Neoproterozoic

Authors:

Swanson-Hysell et al

Abstract:

The Neoproterozoic Era was an interval characterized by profound environmental and biological transitions. Existing age models for Neoproterozoic nonglacial intervals largely have been based on correlation of carbonate carbon isotope values, but there are few tests of the assumed synchroneity of these records between basins. In contrast to the ash-poor successions typically targeted for Neoproterozoic chemostratigraphy, the Tonian to Cryogenian Tambien Group (Tigray region, Ethiopia) was deposited in an arc-proximal basin where volcanic tuffs suitable for U-Pb geochronology are preserved within the mixed carbonate-siliciclastic sedimentary succession. The Tambien Group culminates in a diamictite interpreted to correlate to the ca. 717–662 Ma Sturtian snowball Earth glaciation. New physical stratigraphic data and high-precision U-Pb dates from intercalated tuffs lead to a new stratigraphic framework for the Tambien Group that confirms identification of negative δ13C values from Assem Formation limestones with the ca. 800 Ma Bitter Springs carbon isotope stage. Integration with data from the Fifteenmile Group of northwestern Canada constitutes a positive test for the global synchroneity of the Bitter Spring Stage and constrains the stage to have started after 811.51 ± 0.25 Ma and to have ended before 788.72 ± 0.24 Ma. These new temporal constraints strengthen the case for interpreting Neoproterozoic carbon isotope variation as a record of large-scale changes to the carbon cycle and provide a framework for age models of paleogeographic change, geochemical cycling, and environmental evolution during the radiation of early eukaryotes.

Note posts here, here and here related.

Lower Jaw Fossil Pushes Earliest Example of Genus Homo to Piacenzian Pliocene Neogene

A fossil lower jaw found in the Ledi-Geraru research area, Afar Regional State, Ethiopia, pushes back evidence for the human genus -- Homo -- to 2.8 million years ago, according to a pair of reports published March 4 in the online version of the journal Science. The jaw predates the previously known fossils of the Homo lineage by approximately 400,000 years. It was discovered in 2013 by an international team led by Arizona State University scientists Kaye E. Reed, Christopher J. Campisano and J Ramón Arrowsmith, and Brian A. Villmoare of the University of Nevada, Las Vegas.

For decades, scientists have been searching for African fossils documenting the earliest phases of the Homo lineage, but specimens recovered from the critical time interval between 3 and 2.5 million years ago have been frustratingly few and often poorly preserved. As a result, there has been little agreement on the time of origin of the lineage that ultimately gave rise to modern humans. At 2.8 million years, the new Ledi-Geraru fossil provides clues to changes in the jaw and teeth in Homo only 200,000 years after the last known occurrence of Australopithecus afarensis ("Lucy") from the nearby Ethiopian site of Hadar.

Found by team member and ASU graduate student Chalachew Seyoum, the Ledi-Geraru fossil preserves the left side of the lower jaw, or mandible, along with five teeth. The fossil analysis, led by Villmoare and William H. Kimbel, director of ASU's Institute of Human Origins, revealed advanced features, for example, slim molars, symmetrical premolars and an evenly proportioned jaw, that distinguish early species on the Homo lineage, such as Homo habilis at 2 million years ago, from the more apelike early Australopithecus. But the primitive, sloping chin links the Ledi-Geraru jaw to a Lucy-like ancestor.

"In spite of a lot of searching, fossils on the Homo lineage older than 2 million years ago are very rare," says Villmoare. "To have a glimpse of the very earliest phase of our lineage's evolution is particularly exciting."

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Eurygnathohippus woldegabrieli: A New Horse Species From Pliocene Neogene Ethiopia

A new species of fossil horse from 4.4 million-year-old fossil-rich deposits in Ethiopia,
Eurygnathohippus woldegabrieli, was about the size of a small zebra, Eurygnathohippus woldegabrieli, had three-toed hooves and grazed the grasslands and shrubby woods in the Afar Region, according to its naming in the Journal of Vertebrate Paleontology.

The horse fills a gap in the evolutionary history of horses but is also important for documenting how old a fossil locality is and in reconstructing habitats of human forebears of the time, said Scott Simpson, professor of anatomy at Case Western Reserve's School of Medicine, and co-author of the research. "This horse is one piece of a very complex puzzle that has many, many pieces."

The researchers found the first E. woldegabrieli teeth and bones in 2001, in the Gona area of the Afar Region. This fossil horse was among the diverse array of animals that lived in the same areas as the ancient human ancestor Ardipithecus ramidus, commonly called Ardi.

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Building Construction Which Ties into Local Traditions