Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa.

Data from three African field sites on Pan troglodytes demonstrate an unambiguous pattern of a slower growth rate in wild vs. captive chimpanzee populations. A revised dental growth chronology for chimpanzees is similar to estimated timing of Homo erectus and therefore has implications for interpreting life history in hominins.

An extraordinary collection of 22 immature skeletons from Taı¨National Park, Coˆte d'Ivoire, has provided a rare opportunity to establish the timing of dental eruption and its correlation with skeletal fusion and morphometrics in wild chimpanzees of known chronological ages. Comparison of the immature Taıc himpanzees Pan troglodytes verus with adults from the same population show that sex differences in skeletal maturation apparently appear during the Juvenile II stage, about age 8. A few skeletons from other chimpanzee field sites conform to the dental and skeletal growth in Taı¨chimpanzees. The tempo of wild chimpanzee growth contrasts sharply with the rate demonstrated for captive individuals. Captive chimpanzees may mature as much as 3 years earlier. The ability to link physical development with field observations of immature chimpanzees increases our understanding of their life-history stages. These data provide an improved dataset for comparing the rates of growth among chimpanzees, Homo sapiens and fossil hominids.

A study was undertaken of a unique sample of 63 wild vervet monkeys Cercopithecus aethiops from a single population in Uganda collected over 35 days in 1947. Twenty-five were immature (12 females and 13 males) and 38 were adults (16 females and 22 males). Body mass, external measurements, masticatory and other masses were recorded for each individual at the time of collection, and for a few specimens, the development of the reproductive organs. Each individual was evaluated for cranial capacity, limb length and dental eruption. The comparison of immature and adult animals illustrates the mosaic nature of growth in the different body systems, as well as femalemale differences. An ancestral model is proposed for catarrhine growth and development, with particular reference to sex differences. This model provides a framework for assessment of immatures and for the reconstruction of socio-ecological effects on life-history stages in populations of fossil monkeys, apes and early hominids.

The human body has been shaped by natural selection during the past 4-5 million years. Fossils preserve bones and teeth but lack muscle, skin, fat, and organs. To understand the evolution of the human form, information about both soft and hard tissues of our ancestors is needed. Our closest living relatives of the genus Pan provide the best comparative model to those ancestors. Here, we present data on the body composition of 13 bonobos (Pan paniscus) measured during anatomical dissections and compare the data with Homo sapiens. These comparative data suggest that both females and males (i) increased body fat, (ii) decreased relative muscle mass, (iii) redistributed muscle mass to lower limbs, and (iv) decreased relative mass of skin during human evolution. Comparison of soft tissues between Pan and Homo provides new insights into the function and evolution of body composition.body composition | bonobo | Pan paniscus | human evolution | Homo sapiensT he human body has been shaped by natural selection during the past 4-5 million years. The large brain and expanded neurocranium of Homo sapiens (1,100-1,550 cm 3 ) is triple the size of closely related chimpanzees (Pan, 275-420 cm 3 ) and fossil australopithecines (e.g., Australopithecus afarensis AL-444, 550 cm 3 ; Australopithecus africanus Taung, 382 cm 3 ; and Australopithecus sediba MH1, 420 cm 3 ) (1-6). Long lower limbs in humans accommodate habitual bipedality and contrast with the relatively short lower limbs of quadrupedal African apes. These changes in limb proportions can be tracked across millions of years of australopithecine and early Homo remains, (e.g., partial skeletons of Au. afarensis AL-288 "Lucy," Au. africanus STS 14, Homo erectus WT 15000 "Nariokotome Boy") (7-9).Fossils, even relatively complete ones, preserve only bone, one component of body composition and a small proportion of body mass. The remaining muscle, skin, fat, and vital organs that make up the other 85% do not leave a record, although, separately and together, they underpin locomotor activity, energetics, health, and reproduction (10-14). There has been much speculation about their interrelationships. The "expensive tissue hypothesis" attempts to explain the threefold expansion of the human brain (15-18). It argues that because human brain tissue requires a disproportionately high energy supply, its increase during evolution necessitated a compensatory decrease in another component, the gastrointestinal tract (18). Another hypothesis suggests that body fat in australopithecines was as high as the body fat of modern hunter-gatherers (19). Tests of hypotheses about the evolution of body composition require a comparative database, one that includes the major tissues.One way to fill in the missing information is to compare human body composition with the body composition of our closest living relatives, members of the genus Pan (20, 21). Few such comparative data are available on apes (but cf. 22-25). The rarity of apes in captivity, their long lives, and the logistics of obtaining ...

Objectives In 2008, an immature hominin defined as the holotype of the new species Australopithecus sediba was discovered at the 1.9 million year old Malapa site in South Africa. The specimen (MH1) includes substantial post‐cranial skeletal material, and provides a unique opportunity to assess its skeletal maturation. Methods Skeletal maturity indicators observed on the proximal and distal humerus, proximal ulna, distal radius, third metacarpal, ilium and ischium, proximal femur and calcaneus were used to assess the maturity of each bone in comparison to references for modern humans and for wild chimpanzees (Pan troglodytes). Results In comparison to humans the skeletal maturational ages for Au. sediba correspond to between 12.0 years and 15.0 years with a mean (SD) age of 13.1 (1.1) years. In comparison to the maturational pattern of chimpanzees the Au. sediba indicators suggest a skeletal maturational age of 9–11 years. Based on either of these skeletal maturity estimates and the body length at death of MH1, an adult height of 150–156 cm is predicted. Discussion We conclude that the skeletal remains of MH1 are consistent with an ape‐like pattern of maturity when dental age estimates are also taken into consideration. This maturity schedule in australopiths is consistent with ape‐like estimates of age at death for the Nariokotome Homo erectus remains (KMN‐WT 15000), which are of similar postcranial immaturity to MH1. The findings suggest that humans may have distinctive and delayed post‐cranial schedules from australopiths and H. erectus, implicating a recent evolution of somatic and possibly life history strategies in human evolution.

Fusion of skeletal elements provides markers for timing of growth and is one component of a chimpanzee's physical development. Epiphyseal closure defines bone growth and signals a mature skeleton. Most of what we know about timing of development in chimpanzees derives from dental studies on Pan troglodytes. Much less is known about the sister species, Pan paniscus, with few in captivity and a wild range restricted to central Africa. Here, we report on the timing of skeletal fusion for female captive P. paniscus (n = 5) whose known ages range from 0.83 to age 11.68 years. Observations on the skeletons were made after the individuals were dissected and bones cleaned. Comparisons with 10 female captive P. troglodytes confirm a generally uniform pattern in the sequence of skeletal fusion in the two captive species. We also compared the P. paniscus to a sample of three unknown-aged female wild P. paniscus, and 10 female wild P. troglodytes of known age from the Taï National Park, Côte d'Ivoire. The sequence of teeth emergence to bone fusion is generally consistent between the two species, with slight variations in late juvenile and subadult stages. The direct-age comparisons show that skeletal growth in captive P. paniscus is accelerated compared with both captive and wild P. troglodytes populations. The skeletal data combined with dental stages have implications for estimating the life stage of immature skeletal materials of wild P. paniscus and for more broadly comparing the skeletal growth rates among captive and wild chimpanzees (Pan), Homo sapiens, and fossil hominins.

Dental eruption provides markers of growth and is one component of a chimpanzee's physical development. Dental markers help characterize transitions between life stages, e.g., infant to juvenile. Most of what we know about the timing of development in chimpanzees derives from Pan troglodytes. Much less is known about the sister species, Pan paniscus, with few in captivity and a restricted wild range in central Africa. Here we report on the dental eruption timing for female captive P. paniscus (n = 5) from the Milwaukee and San Diego Zoos whose ages are known and range from birth to age 8.54 years. Some observations were recorded in zoo records on the gingiva during life; others were made at death on the gingiva and on the skeleton. At birth, P. paniscus infants have no teeth emerged. By 0.83 years, all but the deciduous second molars (dm(2) ) (when both upper and lower dentitions are referenced collectively, no super or subscript notation is used) and canines (dc) are emerged. For permanent teeth, results show a sequence polymorphism for an early P4 eruption, not previously described for P. paniscus. Comparisons between P. paniscus and P. troglodytes document absolute timing differences of emergence in upper second incisors (I(2) ), and upper and lower canines (C) and third molars (M3). The genus Pan encompasses variability in growth not previously recognized. These preliminary data suggest that physical growth in captive P. paniscus may be accelerated, a general pattern found in captive P. troglodytes.