A morphometric and taxonomic assessment of a hominine femur from the lower member,Koobi Fora,Lake Turkana

Previous research by this author and others has indicated that species-level differentiation within the hominines can be detected in the femur. The femoral shaft of Homo erectus, relative to H. sapiens, demonstrates small anteroposterior diameters, a distally placed point of minimum shaft breadth, and increased cortical thickness resulting in medullary stenosis. This pattern has been identified in specimens from Choukoutien (I and IV), Olduvai (OH 28), and Lake Turkana (KNM ER 737). Findings reported here include anatomical comparisons and univariate and multivariate analyses based on external and internal shaft morphology. These results indicate that the femoral pattern characteristic of H. erectus can be identified in KNM ER 1481a recovered at Lake Turkana below the KBS tuff. Recent dating of that tuff indicates a date of ca. 1.8 mya, thereby yielding a date for KNM ER 1481a of ? 2.0 mya. Known H. erectus femora extend over a broad span and yet show very low, variability; this pronounced stasis would strongly suggest that, at least in this portion of the postcranium, H. erectus was in a period of profound morphological stasis.     

No skeletal dysplasia in the nariokotome boy KNM‐WT 15000 (homo erectus)—A reassessment of congenital pathologies of the vertebral column

The Nariokotome boy skeleton KNM‐WT 15000 is the most complete Homo erectus fossil and therefore is key for understanding human evolution. Nevertheless, since Latimer and Ohman (2001) reported on severe congenital pathology in KNM‐WT 15000, it is questionable whether this skeleton can still be used as reference for Homo erectus skeletal biology. The asserted pathologies include platyspondylic and diminutive vertebrae implying a disproportionately short stature; spina bifida; condylus tertius; spinal stenosis; and scoliosis. Based on this symptom complex, the differential diagnosis of spondyloepiphyseal dysplasia tarda, an extremely rare form of skeletal dysplasia, has been proposed. Yet, our reanalysis of these pathologies shows that the shape of the KNM‐WT 15000 vertebrae matches that of normal modern human adolescents. The vertebrae are not abnormally flat, show no endplate irregularities, and thus are not platyspondylic. As this is the hallmark of spondyloepiphyseal dysplasia tarda and related forms of skeletal dysplasia, the absence of platyspondyly refutes axial dysplasia and disproportionate dwarfism. Furthermore, we neither found evidence for spina bifida occulta nor manifesta, whereas the condylus tertius, a developmental anomaly of the cranial base, is not related to skeletal dysplasias. Other fossils indicate that the relatively small size of the vertebrae and the narrow spinal canal are characteristics of early hominins rather than congenital pathologies. Except for the recently described signs of traumatic lumbar disc herniation, the Nariokotome boy fossil therefore seems to belong to a normal Homo erectus youth without pathologies of the axial skeleton. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.     

Using geometric morphometrics for integrative taxonomy: an examination of head shapes of milksnakes (genus Lampropeltis)

Species discovery and identification has long relied on traditional morphometric analyses, although molecular methods for species delimitation are becoming increasing popular and important. Despite an increase in studies that rely solely on molecular data to differentiate between species, additional evidence that supports genealogically‐based species delimitation is desirable at least for field and museum identification of species and is part of an integrative approach to taxonomy. The present study uses geometric morphometric (GM) analyses to examine six species of milksnake (genus Lampropeltis) that have recently been delimited based on multilocus data in a coalescent framework. Landmarks are plotted onto the dorsal view of 487 specimens and canonical variate analysis (CVA) is used to determine whether the differences in head shape of these six species can be used to correctly classify specimens. For five of the six species, CVA accurately classifies individuals >70% of the time. The present study illustrates that, although GM‐based analyses may not correctly differentiate between species 100% of the time, GM methods can be useful for detecting shape differences between species and help to corroborate species delimitation. © 2015 The Linnean Society of London     

The dental developmental status of six East African juvenile fossil hominids

Radiographs of five juvenile fossil hominids from Koobi Fora, Kenya are described and presented together with measurements and observations made on the original speciments. Data are also presented for a single specimen from Olduvai Gorge, Tanzania. Four of these specimens are attributed to Paranthropus boisei (KNM ER 812, 1477 1820 and OH 30), and are all of remarkably similar dental developmental status. Conventional age estimates for these specimens of Paranthropus based on the first permanent molar, indicate an age at death of around 2·2 to 3 years. Perikymata counts on permanent lower central incisors of these specimens also indicate an age at death between 2·5 and 3 years. Two specimens attributed to early Homo (KNM ER 820 and 1507), are dentally more mature than specimens of Paranthropus boisei described here being closer to 5 years of age. Differences between the spacing and distribution of perikymata on the surfaces of incisor teeth are now apparent between Homo, Australopithecus. Paranthropus boisei and Paranthropus robustus: these are described in this paper. Details of the dental developmental patterns of these hominids are also discussed in the light of recent publications that have presented data about hominid eruption sequences and fossil hominid growth periods.     

Additional mandibles of Rangwapithecus gordoni,an early Miocene catarrhine from the Tinderet localities of Western Kenya

Two catarrhine mandibles and five isolated teeth have been discovered from Early Miocene localities in Western Kenya. One mandible comes from the well‐known locality of Songhor whereas the other is from a newly discovered locality, Lower Kapurtay, located near Songhor. The mandibles both can clearly be assigned to the species Rangwapithecus gordoni based on molar morphology, which is unique among Early Miocene catarrhines. The isolated specimens can be assigned to Rangwapithecus based on their similarities in morphology to the homologues preserved in the two mandibles. These specimens provide important new information about the dentognathic morphology of Rangwapithecus, which is described in detail. The mandible from Songhor (KNM‐SO 22228) represents the first definitive female mandible of Rangwapithecus. The Lower Kapurtay mandible (KNM‐KT 31234) appears to be male but is much smaller than another recently described male mandible of this species (KNM‐SO 17500) and the type maxilla (KNM‐SO 700). These specimens enable a reassessment of the attributions of all other mandibles and isolated lower teeth of Rangwapithecus, and we present a complete hypodigm of the mandibular and lower dental material for the species. Finally, we provide some additions to the diagnosis of Rangwapithecus gordoni based on previously unknown morphology. Am J Phys Anthropol 153:341–352, 2014. © 2013 Wiley Periodicals, Inc.     

Towards the automated identification of Chrysomya blow flies from wing images

The Old World screwworm fly (OWSF), Chrysomya bezziana (Diptera: Calliphoridae), is an important agent of traumatic myiasis and, as such, a major human and animal health problem. In the implementation of OWSF control operations, it is important to determine the geographical origins of such disease‐causing species in order to establish whether they derive from endemic or invading populations. Gross morphological and molecular studies have demonstrated the existence of two distinct lineages of this species, one African and the other Asian. Wing morphometry is known to be of substantial assistance in identifying the geographical origin of individuals because it provides diagnostic markers that complement molecular diagnostics. However, placement of the landmarks used in traditional geometric morphometric analysis can be time‐consuming and subject to error caused by operator subjectivity. Here we report results of an image‐based approach to geometric morphometric analysis for delivering wing‐based identifications. Our results indicate that this approach can produce identifications that are practically indistinguishable from more traditional landmark‐based results. In addition, we demonstrate that the direct analysis of digital wing images can be used to discriminate between three Chrysomya species of veterinary and forensic importance and between C. bezziana genders.     

Are geometric morphometric analyses replicable? Evaluating landmark measurement error and its impact on extant and fossil Microtus classification

Geometric morphometric analyses are frequently employed to quantify biological shape and shape variation. Despite the popularity of this technique, quantification of measurement error in geometric morphometric datasets and its impact on statistical results is seldom assessed in the literature. Here, we evaluate error on 2D landmark coordinate configurations of the lower first molar of five North American Microtus (vole) species. We acquired data from the same specimens several times to quantify error from four data acquisition sources: specimen presentation, imaging devices, interobserver variation, and intraobserver variation. We then evaluated the impact of those errors on linear discriminant analysis‐based classifications of the five species using recent specimens of known species affinity and fossil specimens of unknown species affinity. Results indicate that data acquisition error can be substantial, sometimes explaining >30% of the total variation among datasets. Comparisons of datasets digitized by different individuals exhibit the greatest discrepancies in landmark precision, and comparison of datasets photographed from different presentation angles yields the greatest discrepancies in species classification results. All error sources impact statistical classification to some extent. For example, no two landmark dataset replicates exhibit the same predicted group memberships of recent or fossil specimens. Our findings emphasize the need to mitigate error as much as possible during geometric morphometric data collection. Though the impact of measurement error on statistical fidelity is likely analysis‐specific, we recommend that all geometric morphometric studies standardize specimen imaging equipment, specimen presentations (if analyses are 2D), and landmark digitizers to reduce error and subsequent analytical misinterpretations.     

Systematics and macroevolution of extant and fossil scalopine moles (Mammalia,Talpidae)

Scalopini is one of the two fully fossorial mole tribes in the family Talpidae, with remarkable adaptations to subterranean lifestyles. Most living Scalopini species are distributed in North America while a sole species occurs in China. On the other hand, scalopine fossils are found in both Eurasia and North America from upper Oligocene strata onwards, implying a complex biogeographical history. The systematic relationships of both extant and fossil Scalopini across North America and Eurasia are revised by conducting phylogenetic analyses using a comprehensive morphological character matrix together with 2D geometric–morphometric analyses of the humeral shape, with a specific emphasis on Mioscalops, a genus commonly found in North America and formerly known as Scalopoides. Our phylogenetic analyses support the monophyly of the tribe Scalopini as well as a proposed two‐subtribe‐division scenario of Scalopini (i.e. Scalopina and Parascalopina), although Proscapanus could not be assigned to either subgenus. Our geometric–morphometric analyses indicate that the European Mioscalops from southern Germany should be allocated to Leptoscaptor, which in turn implies that Mioscalops may be endemic to North America and never arrived in Europe. Examination of biogeographical patterns does not unambiguously determine the geographical origin of Scalopini. Nevertheless, it does support multiple transcontinental colonization events across Asia, Europe and North America. Scapanulus oweni, distributed in central China, is the only remaining representative of one of those out‐of‐North‐America migrations, whereas scalopine moles are common in North America nowadays with up to five species.     

A new morphometric model in distinguishing two closely related extinct brachiopod species

Pseudoatrypa (Atrypida, Brachiopoda) are extinct Paleozoic brachiopods that are the closest relatives of the modern brachiopods, rhynchonellids. Two Paleozoic brachiopod species were qualitatively distinguished based on close examination of phenotypic characters and traditional morphometrics. These species were recovered for the first time from the Givetian localities of Traverse Group of Michigan. The efficacy of geometric morphometric analyses in discriminating species has been proven for various organisms, but rarely studies have been performed in distinguishing brachiopod species. The advanced morphometric model developed here using the Procrustes-based landmark method is based on the analysis of valve shape in two extinct brachiopod species: Pseudoatrypa lineata and Pseudoatrypa devoniana. Results from quantitative analyses reinforce the qualitative identifications of the two species. The application of this method on four different orientations (dorsal, ventral, posterior and anterior regions) of the brachiopods permits the two species to be clearly separated, and this study proposes that the model can be effectively used for future identification and distinction of fossil species. Additionally, this study will aid biologists, paleontologists and neontologists in making appropriate advancement in systematic studies and further assist with gauging biodiversity congruously.     

Late Upper Pleistocene human peopling of the Far East: multivariate analysis and geographic patterns of variation

This research deals with the History of the human peopling of Far East Asia during the Late Upper Pleistocene. It brings some new answers to the question of modern human migrations in the Far East. This study is based on morphometric analysis of 45 fossil crania. The results of the multivariate analyses, combined with the recognition of geographic patterns of variation, separate the fossils into three morphological classes. These three clusters enable us to propose a likely scenario for the human peopling of the Far East from about 67 000 years ago. To cite this article: F. Demeter et al., C. R. Palevol 2 (2003).     

Technical note: Morphometric maps of long bone shafts and dental roots for imaging topographic thickness variation

Qualitative and quantitative characterization through functional imaging of mineralized tissues is of potential value in the study of the odontoskeletal remains. This technique, widely developed in the medical field, allows the bi‐dimensional, planar representation of some local morphometric properties, i.e., topographic thickness variation, of a three‐dimensional object, such as a long bone shaft. Nonetheless, the use of morphometric maps is still limited in (paleo)anthropology, and their feasibility has not been adequately tested on fossil specimens. Using high‐resolution microtomographic images, here we apply bi‐dimensional virtual “unrolling” and synthetic thickness mapping techniques to compare cortical bone topographic variation across the shaft in a modern and a fossil human adult femur (the Magdalenian from Chancelade). We also test, for the first time, the possibility to virtually unroll and assess for dentine thickness variation in modern and fossil (the Neanderthal child from Roc de Marsal) human deciduous tooth roots. The analyses demonstrate the feasibility of using two‐dimensional morphometric maps for the synthetic functional imaging and comparative biomechanical interpretation of cortical bone thickness variation in extant and fossil specimens and show the interest of using this technique also for the subtle characterization of root architecture and dentine topography. More specifically, our preliminary results support the use of virtual cartography as a tool for assessing to what extent internal root morphology is capable of responding to loading and directional stresses and strains in a predictable way. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.     

A missense mutation in the vacuolar protein GOLD36 causes organizational defects in the ER and aberrant protein trafficking in the plant secretory pathway

A central question in cell biology is how the identity of organelles is established and maintained. Here, we report on GOLD36, an EMS mutant identified through a screen for partial displacement of the Golgi marker, ST‐GFP, to other organelles. GOLD36 showed partial distribution of ST‐GFP into a modified endoplasmic reticulum (ER) network, which formed bulges and large skein‐like structures entangling Golgi stacks. GOLD36 showed defects in ER protein export as evidenced by our observations that, besides the partial retention of Golgi markers in the ER, the trafficking of a soluble bulk‐flow marker to the cell surface was also compromised. Using a combination of classical mapping and next‐generation DNA sequencing approaches, we linked the mutant phenotype to a missense mutation of a proline residue in position 80 to a leucine residue in a small endomembrane protein encoded by the gold36 locus ( At1g54030 ). Subcellular localization analyses indicated that GOLD36 is a vacuolar protein and that its mutated form is retained in the ER. Interestingly also, a gold36 knock‐out mutant mirrored the GOLD36 subcellular phenotype. These data indicate that GOLD36 is a protein destined to post‐ER compartments and suggest that its export from the ER is a requirement to ensure steady‐state maintenance of the organelle’s organization and functional activity in relation to other secretory compartments. We speculate that GOLD36 may be a factor that is necessary for ER integrity because of its ability to limit deleterious effects of other secretory proteins on the ER.     

Postnatal temporal bone ontogeny in Pan,Gorilla, and Homo,and the implications for temporal bone ontogeny in Australopithecus afarensis

Assessments of temporal bone morphology have played an important role in taxonomic and phylogenetic evaluations of fossil taxa, and recent three‐dimensional analyses of this region have supported the utility of the temporal bone for testing taxonomic and phylogenetic hypotheses. But while clinical analyses have examined aspects of temporal bone ontogeny in humans, the ontogeny of the temporal bone in non‐human taxa is less well documented. This study examines ontogenetic allometry of the temporal bone in order to address several research questions related to the pattern and trajectory of temporal bone shape change during ontogeny in the African apes and humans. We further apply these data to a preliminary analysis of temporal bone ontogeny in Australopithecus afarensis. Three‐dimensional landmarks were digitized on an ontogenetic series of specimens of Homo sapiens, Pan troglodytes, Pan paniscus, and Gorilla gorilla. Data were analyzed using geometric morphometric methods, and shape changes throughout ontogeny in relation to size were compared. Results of these analyses indicate that, despite broadly similar patterns, African apes and humans show marked differences in development of the mandibular fossa and tympanic portions of the temporal bone. These findings indicate divergent, rather than parallel, postnatal ontogenetic allometric trajectories for temporal bone shape in these taxa. The pattern of temporal bone shape change with size exhibited by A. afarensis showed some affinities to that of humans, but was most similar to extant African apes, particularly Gorilla. Am J Phys Anthropol 151:630–642, 2013. © 2013 Wiley Periodicals, Inc.     

Calibrated chronograms,fossils, outgroup relationships,and root priors: re‐examining the historical biogeography of Geraniales

We re‐examined the recent study by Palazzesi et al., (2012) published in the Biological Journal of the Linnean Society (107: 67–85), that presented the historical diversification of Geraniales using BEAST analysis of the plastid spacer trnL–F and of the non‐coding nuclear ribosomal internal transcribed spacers (ITS). Their study presented a set of new fossils within the order, generated a chronogram for Geraniales and other rosid orders using fossil‐based priors on five nodes, demonstrated an Eocene radiation of Geraniales (and other rosid orders), and argued for more recent (Pliocene–Pleistocene) and climate‐linked diversification of genera in the five recognized families relative to previous studies. As a result of very young ages for the crown of Geraniales and other rosid orders, unusual relationships of Geraniales to other rosids, and apparent nucleotide substitution saturation of the two gene regions, we conducted a broad series of BEAST analyses that incorporated additional rosid fossil priors, used more accepted rosid ordinal topologies, or altered the placement of one fossil Geraniales prior. Our results indicate that their ages are 20–50% too young owing to a combination of (1) strong nucleotide saturation of the DNA regions starting at 65 Mya, (2) lack of a root (rosid stem) or other rosid ordinal stem fossil‐based priors, (3) the inability of the two DNA regions (with alignment issues) to obtain a monophyletic Geraniales as well as reasonable relationships of Geraniales to other rosid orders, and (4) apparent issues with the nodal placement of a Pelargonium fossil. The Geraniales crown is much older (Campanian of the Cretaceous; 86 Mya), the posterior age distribution on all but two fossil nodes are well older than the priors, the placement of a Pelargonium‐like fossil is more likely at the crown rather than the stem, but their models of diversification within several clades linked to climatic and orogeny appear supported. We discuss a number of the inherent issues of relaxed‐clock dating and outline some ‘best practice’ approaches for such studies. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 29–49.     

25‐Hydroxycholesterol Acts in the Golgi Compartment to Induce Degradation of Tyrosinase

Oxysterols play a significant role in cholesterol homeostasis. 25‐Hydroxycholesterol (25HC) in particular has been demonstrated to regulate cholesterol homeostasis via oxysterol‐binding protein and oxysterol‐related proteins, the sterol regulatory element binding protein, and the rate‐limiting enzyme of cholesterol biosynthesis, hydroxymethylglutaryl coenzyme A reductase. We have examined the effect of 25HC on pigmentation of cultured murine melanocytes and demonstrated a decrease in pigmentation with an IC₅₀ of 0.34 μM and a significant diminution in levels of melanogenic protein tyrosinase. Pulse‐chase studies of 25HC‐treated cells demonstrated enhanced degradation of tyrosinase, the rate‐limiting enzyme of melanin synthesis, following endoplasmic reticulum (ER) and Golgi maturation. Protein levels of GS28, a member of an ER/cis‐Golgi SNARE protein complex, were also diminished in 25HC‐treated melanocytes, however levels of the ER chaperone calnexin and the cis‐Golgi matrix protein GM130 were unaffected. Effects of 25HC on tyrosinase were completely reversed by 4α‐allylcholestan‐3α‐ol, a sterol identified by its ability to reverse effects of 25HC on cholesterol homeostasis. Finally, the addition of 25HC to lipid deficient serum inhibited correct processing of tyrosinase. We conclude that 25HC acts in the Golgi compartment to regulate pigmentation by a mechanism shared with cholesterol homeostasis.     

Relationship between osteology and aquatic locomotion in birds: determining modes of locomotion in extinct Ornithurae

The evolutionary history of aquatic invasion in birds would be incomplete without incorporation of extinct species. We show that aquatic affinities in fossil birds can be inferred by multivariate analysis of skeletal features and locomotion of 245 species of extant birds. Regularized discriminant analyses revealed that measurements of appendicular skeletons successfully separated diving birds from surface swimmers and flyers, while also discriminating among different underwater modes of swimming. The high accuracy of this method allows detection of skeletal characteristics that are indicative of aquatic locomotion and inference of such locomotion in bird species with insufficient behavioural information. Statistical predictions based on the analyses confirm qualitative assessments for both foot‐propelled (Hesperornithiformes) and wing‐propelled (Copepteryx) underwater locomotion in fossil birds. This is the first quantitative inference of underwater modes of swimming in fossil birds, enabling future studies of locomotion in extinct birds and evolutionary transitions among locomotor modes in avian lineage.     

A reconsideration of Sphaerodactylus dommeli Böhme, 1984 (Squamata: Gekkota: Sphaerodactylidae), a Miocene lizard in amber

The Miocene gecko in amber, Sphaerodactylus dommeli, is one of the best‐preserved fossil gekkotan species; nonetheless, its identity has been questioned and it has been insinuated to be an iguanian referable to the mega‐diverse genus Anolis. In this paper, we provide digital X‐rays and new osteological evidence that include 11 characters that reaffirms its placement within the infraorder Gekkota and eight characters that specifically place this fossil within the species‐rich genus Sphaerodactylus, in which it was originally described. This contribution seeks to eliminate remaining scepticism about the generic allocation of this species, and to provide a reliable calibration point for ongoing research in squamate phylogenetics, especially for biogeographical studies and molecular dating inference. This contribution also reviews many diagnostic characters for the two genera in question, which is critical for the correct identification of amber‐embedded specimens representing the rich Hispaniolan lizard paleocommunity.     

Geometric morphometric analysis as a proxy to evaluate age‐related change in molar shape variation of low‐crowned Notoungulata (Mammalia)

Shape and age variation in dentition of Paleogene extinct native South American ungulates (Notoungulata) has been traditionally described using qualitative and quantitative approaches, and has played a controversial role in the systematics of several groups. Such is the case of the Notopithecidae, a group of notoungulates with low‐crowned teeth, known from the middle Eocene of Patagonia (Argentina). In this group, as well as in other contemporary families, extreme morphological changes associated to increasing dental wear were originally assumed to represent taxonomic differences; thus, dozens of species were erected, clearly reflecting the difficulty of defining discrete characters. In this contribution, a total of 89 upper molars and 91 lower molars were analyzed distributed in two factors, wear and species; three species of notopithecids were considered as study case, Notopithecus adapinus, Antepithecus brachystephanus, and Transpithecus obtentus, based on the large and well‐identified sample of upper and lower molars for each species. We have coupled geometric morphometric analyses with traditional comparative methods to get a better understanding and interpretation of both the changes in tooth shape contour and the link between shape and ontogeny. In addition, we evaluate the utility of this approach to identify which changes are strictly wear‐related and also test the qualitative characteristics used for diagnosing and differentiating notopithecid species. Our study yielded consistent results when applying independent geometric morphometric analyses on complex structures such as brachydont molar teeth. The landmark data is highly congruent with alternative sources of evidence, such as morphological studies using discrete characters. In notopithecid species, wear is the main factor affecting molar shape, followed by species (in lower molars) and allometry; in addition, lower teeth morphology is more definitive in separating species than upper molars, a fact that entails a key point for systematic studies of Paleogene brachydont notoungulates.