Immature remains are critical for understanding maturational processes in hominin species as well as for interpreting changes in ontogenetic development in hominin evolution. The study of these ...subjects is hindered by the fact that associated juvenile remains are extremely rare in the hominin fossil record. Here we describe an assemblage of immature remains of Homo naledi recovered from the 2013-2014 excavation season. From this assemblage, we attribute 16 postcranial elements and a partial mandible with some dentition to a single juvenile Homo naledi individual. The find includes postcranial elements never before discovered as immature elements in the sub-equatorial early hominin fossil record, and contributes new data to the field of hominin ontogeny.
New ages for flowstone, sediments and fossil bones from the Dinaledi Chamber are presented. We combined optically stimulated luminescence dating of sediments with U-Th and palaeomagnetic analyses of ...flowstones to establish that all sediments containing
fossils can be allocated to a single stratigraphic entity (sub-unit 3b), interpreted to be deposited between 236 ka and 414 ka. This result has been confirmed independently by dating three
teeth with combined U-series and electron spin resonance (US-ESR) dating. Two dating scenarios for the fossils were tested by varying the assumed levels of
Rn loss in the encasing sediments: a maximum age scenario provides an average age for the two least altered fossil teeth of 253 +82/-70 ka, whilst a minimum age scenario yields an average age of 200 +70/-61 ka. We consider the maximum age scenario to more closely reflect conditions in the cave, and therefore, the true age of the fossils. By combining the US-ESR maximum age estimate obtained from the teeth, with the U-Th age for the oldest flowstone overlying
fossils, we have constrained the depositional age of
to a period between 236 ka and 335 ka. These age results demonstrate that a morphologically primitive hominin,
survived into the later parts of the Pleistocene in Africa, and indicate a much younger age for the
fossils than have previously been hypothesized based on their morphology.
The hand of Homo naledi Kivell, Tracy L; Deane, Andrew S; Tocheri, Matthew W ...
Nature communications,
10/2015, Letnik:
6, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A nearly complete right hand of an adult hominin was recovered from the Rising Star cave system, South Africa. Based on associated hominin material, the bones of this hand are attributed to Homo ...naledi. This hand reveals a long, robust thumb and derived wrist morphology that is shared with Neandertals and modern humans, and considered adaptive for intensified manual manipulation. However, the finger bones are longer and more curved than in most australopiths, indicating frequent use of the hand during life for strong grasping during locomotor climbing and suspension. These markedly curved digits in combination with an otherwise human-like wrist and palm indicate a significant degree of climbing, despite the derived nature of many aspects of the hand and other regions of the postcranial skeleton in H. naledi.
The site of Malapa, South Africa, has produced fossil evidence from multiple individuals of Australopithecus sediba including the par tial skeletons designated as MH1 (holotype) and MH2 (paratype). A ...recent ar ticle in this Journal presented the hypothesis that MH1 and MH2 are not one species but instead represent two different genera: Australopithecus and Homo, respectively. Here we briefly evaluate this claim. We review the evidence from across the skeleton that demonstrates that MH1 and MH2 represent a single species, and we highlight other fossil samples that show the same pattern of mandibular ramus variation as observed in MH1 and MH2. The evidence shows that there is no reason to separate MH1 and MH2 into different species or genera based upon mandibular ramus morphology. This case illustrates how misleading small fragments of anatomy can be, why researchers should not use such fragments par ticularly for species and genus-level diagnoses, and why it is essential to use all available evidence. This study shows that the mandibular variation that is present in fossils from Malapa attributed to Australopithecus sediba has parallels in both Australopithecus africanus and in Homo. This helps to demonstrate that mandibular form is not sufficient to provide evidence of species diagnosis, but also that the development and adaptations to diet in Au. sediba were overlapping with those present in other related species of hominins. The MH1 and MH2 skeletons are among the most complete known for Australopithecus, dating to approximately 1.977 million years ago.1,2 The preserved elements of each skeleton include portions of upper and lower limb, thorax, pelvis, mandible, dentition and, for MH1, the face and cranial vault.1,3 These remains are among the most studied of any early hominin specimens. Excavation at Malapa has recovered substantial evidence of the burial position of each skeleton, including joints found in articulation or in close anatomical proximity, with all recovered parts showing a low degree of post-mortem dispersion.4 Additional context comes from the different ontogenetic stages and biological sex of the two skeletons. MH2 is adult and MH1 is juvenile with postcranial and dental elements consistent with a maturational age of between 9 and 11 years when compared to a chimpanzee maturational pattern.5 The pelvic remains of MH1 and MH2 are closely similar in size, and similar in most aspects of morphology, but differ in features related to sex, suggesting female sex for MH2 and male sex for MH1.6,7 The slightly larger size of MH1 in many dental and postcranial measurements is consistent with this sex difference. The metric differences between MH1 and MH2 are consistently slight in comparison to the variation observed within other hominin fossil samples that represent single species, within living humans, and within species of other living great apes. The mandibles of both skeletons preserve most of their mandibular dentition, and the teeth of both individuals are very similar in size and morphology.Significance: This study shows that the mandibular variation that is present in fossils from Malapa attributed to Australopithecussediba has parallels in both Australopithecus africanus and in Homo. This helps to demonstrate that mandibular form is not sufficient to provide evidence of species diagnosis, but also that the development and adaptations to diet in Au. sediba were overlapping with those present in other related species of hominins.
Objectives
A recent study of dental chipping suggested that Homo naledi teeth were exposed to “acute trauma” on a regular basis during life, presumably from the consumption of grit‐laden foods. This ...follows debate concerning the etiology of dental chips in South African hominin teeth that dates back more than half a century. Some have argued that antemortem chips result from consumption of hard foods, such as nuts and seeds or bone, whereas others have claimed that exogenous grit on roots and tubers are responsible. Here we examine the dental microwear textures of H. naledi, both to reconstruct aspects of diet of these hominins and to assess the possibility that hard foods (gritty or otherwise) are the culprits for the unusually high antemortem chip incidence reported.
Methods
We made high‐resolution replicas of original molars and found that ten individuals preserve antemortem wear. These were scanned by white‐light scanning confocal profilometry and analyzed using scale‐sensitive fractal analysis. Resulting data were compared with those published for other fossil hominins and extant non‐human primates.
Results
Our results indicate that H. naledi had complex microwear textures dominated by large, deep pits. The only known fossil hominin with higher average texture complexity is Paranthropus robustus, and the closest extant primates in a comparative baseline series appear to be the hard‐object feeder, Cercocebus atys, and the eurytopic generalist, Papio ursinus.
Conclusions
This study suggests that H. naledi likely consumed hard and abrasive foods, such as nuts or tubers, at least on occasion, and that these might well be responsible for the pattern of chipping observed on their teeth.
Six
early juveniles were recovered from U.W. 101 (Dinaledi Chamber), U.W. 102 (Lesedi Chamber), and U.W. 110 in the Rising Star cave system.
This paper develops the information for the
early juvenile ...life stage, as defined by a combination of deciduous and permanent dentition, and the eruption of the first permanent molar.
The growing number of young individuals recovered from the Rising Star cave system allows us to gain a better understanding of their variation, or lack thereof, and provides a basis to estimate broad ranges for age at death of the individuals. The individuals are identified and described through craniodental remains and spatial associations.
Our results show that the teeth are remarkably consistent across the localities in their metric and non-metric traits, and our analyses refine previous estimations on dental eruptions with the first permanent molar erupting first in the sequence among permanent teeth.
Australopithecus prometheus is a nomen nudum Berger, Lee R.; Hawks, John
American journal of physical anthropology,
February 2019, 2019-02-00, 20190201, Letnik:
168, Številka:
2
Journal Article
New discoveries and dating of fossil remains from the Rising Star cave system, Cradle of Humankind, South Africa, have strong implications for our understanding of Pleistocene human evolution in ...Africa. Direct dating of
fossils from the Dinaledi Chamber (Berger et al., 2015) shows that they were deposited between about 236 ka and 335 ka (Dirks et al., 2017), placing
in the later Middle Pleistocene. Hawks and colleagues (Hawks et al., 2017) report the discovery of a second chamber within the Rising Star system (Dirks et al., 2015) that contains
remains. Previously, only large-brained modern humans or their close relatives had been demonstrated to exist at this late time in Africa, but the fossil evidence for any hominins in subequatorial Africa was very sparse. It is now evident that a diversity of hominin lineages existed in this region, with some divergent lineages contributing DNA to living humans and at least
representing a survivor from the earliest stages of diversification within
. The existence of a diverse array of hominins in subequatorial comports with our present knowledge of diversity across other savanna-adapted species, as well as with palaeoclimate and paleoenvironmental data.
casts the fossil and archaeological records into a new light, as we cannot exclude that this lineage was responsible for the production of Acheulean or Middle Stone Age tool industries.
In 1996, Grün and coworkers provided an ESR age determination for a hominin molar from Florisbad, South Africa, at 259 ± 35 ka. The most anatomically informative hominin specimen from Florisbad is a ...fragmentary craniofacial specimen, attributed by many to early
, which has been assumed to derive from the same individual as this tooth. Since 1996, evidence about the evolutionary context for the later Middle Pleistocene and its associated hominins in Africa had markedly changed. If the Florisbad date is accurate and if the molar is associated with the craniofacial specimen, this evidence may suggest that
coexisted in time and geography with
in southern Africa. Thus, the accuracy for all dates needs critical investigation. This study examines the published record of excavation and subsequent analyses for the Florisbad material. We find that the contemporary records raise doubt about the contemporaneity of the tooth and calvaria. The site's complex stratigraphy and the details about the tooth's discovery also pose challenges for the previous ESR age estimate. Because the fragmentary cranial specimen has value for morphological comparisons, developing additional means of understanding its geological age is necessary. The current data do not demonstrate the presence of
in southern Africa at ~260 ka.
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