New 1.5 million-year-old Homo erectus maxilla from Sangiran (Central Java, Indonesia)

Sangiran (Solo Basin, Central Java, Indonesia) is the singular Homo erectus fossil locale for Early Pleistocene Southeast Asia. Sangiran is the source for more than 80 specimens in deposits with ⁴⁰Ar/³⁹Ar ages of 1.51-0.9 Ma. In April 2001, we recovered a H. erectus left maxilla fragment (preserving P³- M²) from the Sangiran site of Bapang. The find spot lies at the base of the Bapang Formation type section in cemented gravelly sands traditionally called the Grenzbank Zone. Two meters above the find spot, pumice hornblende has produced an ⁴⁰Ar/³⁹Ar age of 1.51 ± 0.08 Ma. With the addition of Bpg 2001.04, Sangiran now has five H. erectus maxillae. We compare the new maxilla with homologs representing Sangiran H. erectus, Zhoukoudian H. erectus, Western H. erectus (pooled African and Georgian specimens), and Homo habilis. Greatest contrast is with the Zhoukoudian maxillae, which appear to exhibit a derived pattern of premolar-molar relationships compared to Western and Sangiran H. erectus. The dental patterns suggest distinct demic origins for the earlier H. erectus populations represented at Sangiran and the later population represented at Zhoukoudian. These two east Asian populations, separated by 5000 km and nearly 800 k.yr., may have had separate origins from different African/west Eurasian populations.     

Locomotor activity differences between sympatric patas monkeys (Erythrocebus patas) and vervet monkeys (Cercopithecus aethiops): Implications for the evolution of long hindlimb length in Homo

Homo erectus is notable for its taller stature and longer lower limbs relative to earlier hominids, but the selective pressures favoring such long limbs are unclear. Among anthropoid primates, patas monkeys (Erythrocebus patas) and extant hominids share several extreme characteristics involved with foraging and movement, including the relatively longest lower limb proportions, longest daily travel distances and largest home ranges for their body or group size, occupancy of some of the driest habitats, and very efficient thermoregulatory systems. We suggest that patas monkeys are an appropriate behavioral model with which to speculate on the selective pressures that might have operated on H. erectus to increase lower limb length. Here, in a comparison of the locomotor activities of patas monkeys and sympatric, closely related vervet monkeys (Cercopithecus aethiops), we provide evidence for the hypothesis that patas use their long stride more to increase foraging efficiency while walking than to run, either from predators or otherwise. Am J Phys Anthropol 105:199–207, 1998. © 1998 Wiley-Liss, Inc.     

The endocast from Dana Aoule North (DAN5/P1): A 1.5 million year-old human braincase from Gona,Afar, Ethiopia

The nearly complete cranium DAN5/P1 was found at Gona (Afar, Ethiopia), dated to 1.5–1.6 Ma, and assigned to the species Homo erectus. Its size is, nonetheless, particularly small for the known range of variation of this taxon, and the cranial capacity has been estimated as 598 cc. In this study, we analyzed a reconstruction of its endocranial cast, to investigate its paleoneurological features. The main anatomical traits of the endocast were described, and its morphology was compared with other fossil and modern human samples. The endocast shows most of the traits associated with less encephalized human taxa, like narrow frontal lobes and a simple meningeal vascular network with posterior parietal branches. The parietal region is relatively tall and rounded, although not especially large. Based on our set of measures, the general endocranial proportions are within the range of fossils included in the species Homo habilis or in the genus Australopithecus. Similarities with the genus Homo include a more posterior position of the frontal lobe relative to the cranial bones, and the general endocranial length and width when size is taken into account. This new specimen extends the known brain size variability of Homo ergaster/erectus, while suggesting that differences in gross brain proportions among early human species, or even between early humans and australopiths, were absent or subtle.     

Brief communication: The human humerus from the Broken Hill Mine, Kabwe, Zambia

The distal half of a right human humerus (E.898), recovered ex situ in 1925 by Hrdli?ka at the Broken Hill Mine, Kabwe, Zambia, has figured prominently in assessments of Middle Pleistocene Homo postcranial variation and of the phylogenetic polarity and functional anatomy of Pleistocene Homo upper limb morphology. Reassessment of distal humeral features that distinguish modern human and some archaic Homo humeri, especially relative olecranon breadth and medial and lateral pillar thicknesses, confirm previous studies placing it morphologically close to recent humans, as well as possibly to Early Pleistocene Homo. However, it completely lacks stratigraphic context, and there is faunal and archeological evidence for human activity at Broken Hill from the Middle Pleistocene to the Holocene. Given its uncertain geological age and modern human morphology, the Broken Hill E.898 humerus should not be used in analyses of Pleistocene humans until it is securely dated. Am J Phys Anthropol 149:312–317, 2012. © 2012 Wiley Periodicals, Inc.     

Relevance of aquatic environments for hominins: a case study from Trinil (Java, Indonesia)

Knowledge about dietary niche is key to understanding hominin evolution, since diet influences body proportions, brain size, cognition, and habitat preference. In this study we provide ecological context for the current debate on modernity (or not) of aquatic resource exploitation by hominins. We use the Homo erectus site of Trinil as a case study to investigate how research questions on possible dietary relevance of aquatic environments can be addressed. Faunal and geochemical analysis of aquatic fossils from Trinil Hauptknochenschicht (HK) fauna demonstrate that Trinil at ∼1.5 Ma contained near-coastal rivers, lakes, swamp forests, lagoons, and marshes with minor marine influence, laterally grading into grasslands. Trinil HK environments yielded at least eleven edible mollusc species and four edible fish species that could be procured with no or minimal technology. We demonstrate that, from an ecological point of view, the default assumption should be that omnivorous hominins in coastal habitats with catchable aquatic fauna could have consumed aquatic resources. The hypothesis of aquatic exploitation can be tested with taphonomic analysis of aquatic fossils associated with hominin fossils. We show that midden-like characteristics of large bivalve shell assemblages containing Pseudodon and Elongaria from Trinil HK indicate deliberate collection by a selective agent, possibly hominin.     

A new species of giant marabou stork (Aves: Ciconiiformes) from the Pleistocene of Liang Bua,Flores (Indonesia)

Fossils of the genus Leptoptilos from the Pleistocene of Liang Bua, Flores, Indonesia, belong to a new species of giant marabou stork, Leptoptilos robustus sp. nov. This giant bird, estimated at 1.80 m in length, was similar in dimensions to extant Leptoptilos dubius, except for the tibiotarsus. The thick cortical bone wall of the tibiotarsus and the estimated weight of 16 kg imply a reduced flight capability. Osteological and biometric characters suggest that L. robustus is most closely related to L. dubius. An evolutionary lineage is proposed in which a volant L. dubius‐like ancestor in the Middle Pleistocene evolved into the Late Pleistocene L. robustus on Flores, with a concomitant reduction of the ability to fly and an increase in body size. The large body size and terrestrial lifestyle of L. robustus are responses to an unbalanced, insular environment with abundant prey items and a lack of mammalian carnivores, and emphasize the extraordinary nature of the Homo floresiensis fauna. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 707–724.     

Acoustic communication and burrow acoustics are reflected in the ear morphology of the coruro (Spalacopus cyanus, Octodontidae), a social fossorial rodent

We studied the middle and inner ears of seven adult coruros (Spalacopus cyanus), subterranean and social rodents from central Chile, using free-hand dissection and routine staining techniques. Middle ear parameters that were focused on here (enlarged bullae and eardrums, ossicles of the "freely mobile type") are believed to enhance hearing sensitivity at lower frequencies. The organ of Corti was of a common mammalian type and revealed three peaks of higher inner hair cell densities. Based on a position frequency map, frequencies were assigned to the respective peaks along the basilar membrane. The first peak at around 300-400 Hz is discussed with respect to the burrow acoustics, while the peak around 10-20 kHz is probably a plesiomorphic feature. The most pronounced peak at around 2 kHz reflects the frequency at which the main energy of vocal communication occurs. The morphology of the ear of the coruro corresponds to the typical pattern seen in subterranean rodents (low frequency and low-sensitivity hearers), yet, at the same time, it also deviates from it in several functionally relevant features.     

Computed tomography and enamel thickness of maxillary molars of Plio-Pleistocene hominids from Sterkfontein, Swartkrans, and Kromdraai (South Africa): An exploratory study.

This paper is one in a series which explores the possibility of using the non-destructive CT technique to identify patterns in tooth enamel distribution and structure of hominid molars from Plio-Pleistocene sites in South Africa, notably Swartkrans, Sterkfontein, and Kromdraai. Whereas previous investigators have emphasised gross differences in absolute and relative or average enamel thickness between hominid taxa, the present study highlights differences in enamel thickness over functionally significant regions of the crown. Differences in the distribution of enamel in A. robustus, A. africanus, and Homo sp. are identified through the use of bivariate and multivariate analyses, and are interpreted in terms of dietary regimes.     

Population structure,shell morphology,age and condition of the freshwater mussel Hyridella menziesi (Unionacea: Hyriidae) from seven lake and river sites in the Waikato River system

Populations of the freshwater mussel Hyridella menziesi were compared from six lakes and one river site along the Waikato River system, North Island, New Zealand. Estimated densities ranged from several hundred per square metre in Lake Taupo to less than one per square metre in Lake Karapiro. Length-frequencies were similar at all sites, with unimodal distributions and a notable absence of any individuals less than 20 mm long. The extent of shell erosion varied from sites where most mussels had less than 1% of the right valve affected (i.e., Ohakuri & Karapiro), to Lake Aratiatia where most shells had erosion over 1–20% of their surface. Taupo and Ohakuri mussels showed an unusually high incidence (over 50%) of internal shell abnormalities (including dulling, deformities and protuberances). Canonical discrimination based on shell length, height, width and weight clearly separated Taupo and Ohakuri mussels from all other sites, and ANCOVA on morphological characteristics confirmed significant differences between sites. Physical condition indices (based on dry flesh weight per shell weight and shell volume) showed an increasing downstream trend, but this was not significantly correlated with food availability (i.e., chlorophyll a concentration) because of unexpectedly low condition in lakes Ohakuri and Karapiro. Length v. age relationships contained considerable scatter and did not show between-site differences. Measured differences in external erosion, internal shell abnormalities and morphology were attributed to physical, chemical and biological factors. Use of mussels for environmental monitoring must take these background differences into account.     

Endocranial morphology of Pygoscelis calderensis (Aves,Spheniscidae) from the Neogene of Chile and remarks on brain morphology in modern Pygoscelis

The endocranial anatomy of Pygoscelis calderensis, a fossil species from the Bahía Inglesa Formation (Middle Miocene–Pliocene) of Chile, South America, was described through CT scans. Reconstructions of the fossil P. calderensis and endocasts for the living Pygoscelis adeliae, and Pygoscelis papua are provided here for the first time. Comparisons with the extant congeneric species P. adeliae, Pygoscelisantarctica and P. papua indicate that the morphological pattern of the brain and inner ear of the extant pygoscelids has been present already in the Middle Miocene. The neurological morphology suggests that the paleobiology of the extinct form would have been similar to the extant species. It was probably true for diet, feeding behaviour and diving kinematics.     

The evolutionary history of Fagus in western Eurasia: Evidence from genes, morphology and the fossil record

 Fagus (beech) is among the most abundant and economically important genera of broad-leaved trees in northern hemisphere temperate forests. The number of modern taxa present in Europe and Asia Minor has long been a matter of debate and up to five species have been recognised. To resolve taxonomic and phylogenetic relationships we conducted morphological and molecular genetic analyses in western Eurasiatic taxa and evaluated palaeontological evidence. To place our findings from western Eurasiatic populations in a broader context additional East Asiatic and North American species of the same subgenus Fagus as well as two species of the subgenus Engleriana were included in our study. The morphological features exhibited in western Eurasiatic populations of Fagus show a west-east gradient that is characterised by strongly overlapping variability between geographical races. Fagus populations from Asia Minor exhibit an even higher variability that is also reflected in their genetic variability of nuclear rDNA internal transcribed spacer (ITS) sequences. The intraspecific genetic variability recorded here is in conflict with previous ITS studies in Fagus. The high amount of ITS polymorphism within Fagus from western Eurasia along with the clinal variation observed for morphological characters suggest the presence of only a single species, Fagus sylvatica L., in Europe and Asia Minor. Previously recognised taxa such as F. orientalis Lipsky and Fagus moesiaca (Maly) Czeczott should therefore be treated as synonyms of Fagus sylvatica. Although species belonging to the subgenus Engleriana were genetically distinct from species of the subgenus Fagus, relationships within the subgenus Fagus could not be clearly resolved. A reason for this could be the low rate of diversification in Fagus during the early phase of range expansion of the genus in the Oligocene period as indicated by the uniformity of leaf and cupule/nut fossils. This may account for the low overall ITS divergence and the high degree of polymorphism encountered in the subgenus Fagus and points to a late differentiation of western Eurasiatic and eastern Asiatic species. Area disruptions during the Pleistocene and the post-glacial recolonisation of western Europe appear to have caused the west-east gradient that is apparent in modern Fagus of western Eurasia but absent in Late Tertiary ancestors of Fagus sylvatica. Received June 22, 2001 Accepted February 25, 2002     

Feeding mechanics and dietary implications in the fossil sloth Neocnus (Mammalia: Xenarthra: Megalonychidae) from haiti

Haitian species of the extinct ground sloth genus Neocnus (Mammalia: Pilosa: Megalonychidae) have previously been hypothesized to have a much reduced jugal bone and a correspondingly reduced masseter musculature but a paucity of specimens has prevented further investigation of this hypothesis. Recent discovery of jugal bones belonging to Haitian specimens of Neocnus within the University of Florida Museum collections enables the element to be more accurately described. The discovery also makes it possible to explore mastication in these sloths. Osteological characters related to feeding were examined, along with comparative estimations of bite force with the extant tree sloths, Bradypus and Choloepus, and their known dietary habits as a means to infer aspects of the paleodiet of Neocnus. There is a significant difference in moment arm calculations for m. masseter between predicted and actual jugals, but the overall significance for bite force is lost and hampered by small sample size. Neocnus demonstrates a variety of characters that are similar to those of Bradypus and not to Choloepus, which is a close phylogenetic relative. The masticatory musculature of Neocnus enabled a chewing cycle emphasizing a grinding combination of mesiodistal and linguobuccal movements of the molariform dentition. The orientations of m. masseter and m. temporalis are estimated to produce relatively high bite force ratios that imply a masticatory system with stronger versus faster components. Because of the similarity of bite forces and jaw mechanics to those of Bradypus, in addition to a number of osteological adaptations indicative of herbivorous grazers (elevated mandibular condyle, large and complex masseter, and robust angular process), the Haitian forms of Neocnus are considered to have been selective feeders with a folivorous diet. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.