“Meganthropus” cranial fossils from Java

There are now twelve significant hominid cranial fossils from the Lower and Middle Pleistocene of Java, all but two being from the Sangiran site. Most of this material is well-known in the literature, but three skulls, possibly representing “Meganthropus” are here described in detail for the first time. Most scholars have assigned them all toHomo erectus, while others have suggested that they represent as many as four different hominoid taxa. The author argues that they represent two possible species of hominids. “Meganthropus” I, II, and III are more massive than any of the knownH. erectus specimens. They are also relatively higher vaulted, apparently smaller brained, and have unusually thick lower occipital planes. “Meganthropus” may represent a species that separated fromH. erectus upon its arrival to Java.     

Can extinction rates be estimated without fossils?

There is considerable interest in the possibility of using molecular phylogenies to estimate extinction rates. The present study aims at assessing the statistical performance of the birth-death model fitting approach to estimate speciation and extinction rates by comparison to the approach considering fossil data. A simulation-based approach was used. The diversification of a large number of lineages was simulated under a wide range of speciation and extinction rate values. The estimators obtained with fossils performed better than those without fossils. In the absence of fossils (e.g. with a molecular phylogeny), the speciation rate was correctly estimated in a wide range of situations; the bias of the corresponding estimator was close to zero for the largest trees. However, this estimator was substantially biased when the simulated extinction rate was high. On the other hand the estimator of extinction rate was biased in a wide range of situations. Surprisingly, this bias was lesser with medium-sized trees. Some recommendations for interpreting results from a diversification analysis are given.     

A fungal analog for newfoundland ediacaran fossils?

We propose that some of the more conspicuous Ediacaran fossilsfrom the Avalon Peninsula of Newfoundland, including Aspidella,Charnia, and Charniodiscus, were biologically similar to membersof the Kingdom Fungi. These organisms were multicellular ormultinuclear, lived below the photic zone, could not move ordefoul themselves, did not exhibit taphonomic shrinkage, andwere not transported or moved. Aspidella, in particular, appearsto exhibit indeterminate growth without a maximum size constraint,and appears to show growth zonations similar to modern mycelia.Other fossils from this deposit exhibit a fractal-like growthpattern. Together, these features falsify algal, lichen, andmetazoan interpretations of these fossils, yet reflect characteristicsof modern fungal mycelia. We emphasize that although no MistakenPoint fossil appears to be a metazoan, not all of the MistakenPoint taxa, and not all of the Ediacaran organisms in general,can reasonably be interpreted using a fungal analogy. Furthermore,the hypothesis that these fossils were functionally fungus-likeneed not imply that the organisms were members of the crown-groupFungi. We propose further tests for evaluating both this functionalhypothesis and the phylogenetic hypothesis that these organismswere members of the total-group Fungi.     

Are the small human-like fossils found on Flores human endemic cretins?

Fossils from Liang Bua (LB) on Flores, Indonesia, including a nearly complete skeleton (LB1) dated to 18kyr BP, were assigned to a new species, Homo floresiensis. We hypothesize that these individuals are myxoedematous endemic (ME) cretins, part of an inland population of (mostly unaffected) Homo sapiens. ME cretins are born without a functioning thyroid; their congenital hypothyroidism leads to severe dwarfism and reduced brain size, but less severe mental retardation and motor disability than neurological endemic cretins. We show that the fossils display many signs of congenital hypothyroidism, including enlarged pituitary fossa, and that distinctive primitive features of LB1 such as the double rooted lower premolar and the primitive wrist morphology are consistent with the hypothesis. We find that the null hypothesis (that LB1 is not a cretin) is rejected by the pituitary fossa size of LB1, and by multivariate analyses of cranial measures. We show that critical environmental factors were potentially present on Flores, how remains of cretins but not of unaffected individuals could be preserved in caves, and that extant oral traditions may provide a record of cretinism.     

Why are there so many insect species? Perspectives from fossils and phylogenies

Over half of all described species are insects, but until recently our understanding of the reasons for this diversity was based on very little macroevolutionary evidence. Here I summarize the hypotheses that have been posed, tests of these hypotheses and their results, and hence identify gaps in knowledge for future researchers to pursue. I focus on inferences from the following sources: (i) the fossil record, normally at family level, and (ii) insect phylogenies, sometimes combined with: (iii) the species richness of insect higher taxa, and (iv) current extinction risks. There is evidence that the species richness of insects has been enhanced by: (i) their relative age, giving time for diversification to take place; (ii) low extinction rates. There is little evidence that rates of origination have generally been high or that there are limits on numbers of species. However, the evidence on macroevolutionary rates is not yet so extensive or coherent as to present unequivocal messages. As regards morphological, ecological, or behavioural hypotheses, there is evidence that diversity has been enhanced by (iii) flight or properties resulting from it like enhanced dispersal, (iv) wing folding, and (v) complete metamorphosis. However, in all these cases the evidence is somewhat equivocal, either because of statistical issues or because evidence from different sources is conflicting. There is extensive evidence that diversity is affected by (vi) the ecological niche. Comparative studies indicate that phytophagy generally increases net diversification rates, and reduces extinction risk. However, niche specialization is also associated with an increase in extinction risk. Small body size (vii) is often associated with low extinction risk in comparative studies, but as yet there is no solid evidence that it consistently enhances net rates of diversification. Mouthpart diversity (viii) has generally increased over time in the insects, but cannot explain the apparent great increase in diversity seen in the Cretaceous and Tertiary. Sexual selection and sexual conflict (ix) are two processes that are widespread in insects, and there is comparative evidence linking both to increased diversification. Although some comparative evidence links tropical distributions (x) to increased rates of diversification, the extent to which latitudinal richness gradients are unusual in insects is equivocal. There is little to no direct evidence from fossils and phylogenies that insect diversity has generally been affected by (i) sensory- or neuro-sophistication, (ii) population size or density, (iii) generation time or fecundity, (iv) the presence of an exoskeleton or cuticle, (v) segmentation or appendage diversity, (vi) adaptability or genetic versatility, though all of these remain plausible hypotheses awaiting further tests. The data suggest that the insect body ground plan itself had no direct effect on insect diversity. Thus, whilst studies to date have given substantial understanding, substantial gaps still remain. Future challenges include: (i) interpreting conflicting messages from different sources of data; (ii) rating the importance of different hypotheses that are statistically supported; (iii) linking specific proximate to specific ultimate explanations and vice versa; and (iv) understanding how different ultimate hypotheses might be dependent on each other.     

Were the Spy fossils evolutionary intermediates between Classic Neandertal and Modern Man?

The author re-examined the Spy Mousterian skeletons. Spy I is a female with a cranial capacity of ± 1300 cm³ and Spy II a male with 1504 cm³ cranial capacity. Both postcranial skeletons, the neurocranium of Spy I and anatomical details of the Spy II skull are of preponderant Neandertal character.Hrdlička (1930) supposed that the Spy fossils were evolutionary intermediates between Classic Neandertal and Modern Man on the basis of the following arguments: (a) the presence of supraorbital arches in the Spy II Skull, (b) the modern profile of the Spy II front, (c) the absence of occipital “chignon” in Spy II, (d) the generally modern cranial shape of Spy II, (e) the smallness of teeth and (f) the modern characters of the Spy I mandible. Among these arguments (a) and (b) indicate borderline cases interpretable also in a different way; others are invalid.The Spy fossils are phylogenetically non-transitional Neandertals.     

Why collagens best survived in fossils? Clues from amino acid thermal stability

Explaining why type I collagens are preferentially preserved in the geological time scale remains a challenge. Several pieces of evidence indicate that its rich content in the bone and its unique, stable structure played key roles in its preservation. By considering the distinct thermal stability of amino acids, we reveal that the elevated abundance of thermostable amino acid residues in type I collagens also contribute to its survival.     

The late Neandertal supraorbital fossils from Vindija Cave,Croatia: a biased sample?

The late Neandertal sample from Vindija (Croatia) has been described as transitional between the earlier Central European Neandertals from Krapina (Croatia) and modern humans. However, the morphological differences indicating this transition may rather be the result of different sex and/or age compositions between the samples. This study tests the hypothesis that the metric differences between the Krapina and Vindija supraorbital samples are due to sampling bias. We focus upon the supraorbital region because past studies have posited this region as particularly indicative of the Vindija sample's transitional nature. Furthermore, the supraorbital region varies significantly with both age and sex.We analyzed four chords and two derived indices of supraorbital torus form as defined by Smith & Ranyard (1980, Am. J. phys. Anthrop.93, pp. 589-610). For each variable, we analyzed relative sample bias of the Krapina and Vindija samples using three sampling methods. In order to test the hypothesis that the Vindija sample contains an over-representation of females and/or young while the Krapina sample is normal or also female/young biased, we determined the probability of drawing a sample of the same size as and with a mean equal to or less than Vindija's from a Krapina-based population. In order to test the hypothesis that the Vindija sample is female/young biased while the Krapina sample is male/old biased, we determined the probability of drawing a sample of the same size as and with a mean equal or less than Vindija's from a generated population whose mean is halfway between Krapina's and Vindija's. Finally, in order to test the hypothesis that the Vindija sample is normal while the Krapina sample contains an over-representation of males and/or old, we determined the probability of drawing a sample of the same size as and with a mean equal to or greater than Krapina's from a Vindija-based population. Unless we assume that the Vindija sample is female/young and the Krapina sample is male/old biased, our results falsify the hypothesis that the metric differences between the Krapina and Vindija samples are due to sample bias.     

First record of Cisuralian–Guadalupian plant fossils from the Shan Plateau,eastern Myanmar

Permian plant fossils have never been reported from the Shan Plateau in eastern Myanmar. Recently, a black to gray carbonaceous mudstone unit containing abundant plant fossils was discovered just below the lowest part of Thitspin Limestone Formation from the Linwe Area, eastern Myanmar. Although only five taxa were identified, the plant assemblage provides the first evidence of the occurrence of Cathaysian elements in eastern Myanmar and potentially indicates the presence of a highly diverse Permian flora. Among the five species, Cordaites principalis and Annularia mucronata were cosmopolitan species; while Callipteridum cf. koraiense, Taeniopteris crassinervis Mo and Rhipidopsis lobata were mostly recorded in the Cathaysia Flora. Therefore, the present assemblage generally indicates a palaeobiogeographical affinity to the Cathaysian Province. Stratigraphically, Callipteridum cf. koraiense was mainly reported from Cisuralian to Wordian; whereas Taeniopteris crasssnervis Mo and Rhipidopsis lobata were recorded from Capitanian to Changhsingian, which suggests a general Permian age based on the plant assemblage itself only. However, the carbonaceous mudstone at the outcrop is overlain by the Thitspin Limestone Formation containing middle Guadalupian fusulinids. Based on previous faunal analyses, the Sibumasu terrane contains typical Gondwanan cold-water faunas during the early Cisuralian, warm-water faunas occurred after Sakmarian. Thus, age of the fossil-plant-containing carbonaceous mudstone is very likely between late Cisuralian and early Guadalupian as constrained by its overlying fusulinids and its warm Cathaysian palaeobiogeographical affinity.     

New microbial fossils from ∼1.3 billion‐year‐old rocks of Eastern California

New types of microbial fossils and new occurrences of fossils previously reported only from the Beck Spring Dolomite of the Pahrump Group are now recognized from each of the three formations of the Pahrump Group (Crystal Spring Formation, Beck Spring Dolomite, and Kingston Peak Formation) approximately 1.3 X 10° years old. Comprising perhaps eight or nine distinctive forms, these fossils are characteristically preserved as faint ghostlike structures whose low‐contrast outlines are clearly revealed only when illuminated by a xenon lamp and recorded on high‐contrast film. They represent a distinctive, previously overlooked or neglected type of preservation that has significantly extended the known distribution of microbial fossils in the Pahrump. They include the oldest occurrence known to us of filaments designatable as Girvanella and apparently the first from rocks of pre‐Phanerozoic age. Similar fossils were also found, using the same techniques, in the Chuar Group of the Grand Canyon and in the Uluntui Suite of middle Riphean age in eastern Siberia. Although time correlation of pre‐Phanerozoic rocks based on similar microbial assemblages would be premature, similarity between such assemblages in all formations of the Pahrump Group and with that of the Uluntui Suite is consistent with the inferred unity and middle Riphean age of the Pahrump Group. In addition to the Girvanella we find two smaller types of filaments, two kinds of simple spheroids, and three composite forms (two spheroids and one stalked cluster) that attain diameters up to 80 μm and are probably eucaryotic.     

Rings without a lord? Enigmatic fossils from the lower Palaeozoic of Bohemia and the Carnic Alps

Fossilized ring‐like structures with enigmatic function and taxonomic affiliation were recovered for the first time from the Upper Ordovician of the Carnic Alps and the Silurian of Bohemia. These rings, already mentioned as minor constituents in previous conodont studies (e.g. Webers 1966, p. 1; Bischoff 1973, p. 147), were reported from the Palaeozoic of several regions in Europe and North America. Originally considered as inwardly accreted adhering discs of a benthic hyolithelminth worm with a phosphatic tubular projection, they were later reinterpreted in relation to a putative crinoid epibiont or even as possible scyphozoans. Despite a long debate, neither the function of the enigmatic Palaeozoic rings nor their taxonomic affiliation has been fully clarified. The studied material, extracted by a standard technique in use for conodonts, consists of 235 elements from 16 stratigraphic levels in the Plöcken Formation (Carnic Alps, Cellon Section; Amorphognathus ordovicicus Biozone, Hirnantian, Ordovician) and in the Kopanina Formation (Bohemia, Mu?lovka Quarry; Polygnathoides siluricus Biozone, Ludfordian, Silurian). To explore whether ring size and shape changed over time, we employed a novel combination of geometric morphometric approaches for outlines with no ‘homologous’ landmarks and showed that only size appreciably varied with an increase of ca. 20%. The emerging data from this study are consistent with the interpretation of the rings as an adhering structure of a benthic organism living on a relatively uniform hard substrate.     

Trace fossils in middle to late triassic fluvial redbeds,pranhita‐godavari valley,south India

Several morphological varieties of trace fossils abound in Middle and Late Triassic fluvial redbeds in the Pranhita‐Godavari Valley, south India, including Skolithos, Palaeophycus, Taenidium, escape burrows, and a type of trace very similar to ‘small stuffed burrows’ from the Triassic of Greenland. Burrow morphology was influenced by local hydrodynamic conditions. The distribution of burrows was facies controlled; some forms are restricted to channel deposits whereas others occur only in floodplains. Vertical dwelling burrows (Skolithos) occur in both channel and floodplain deposits. Horizontal structures representing deposit feeding (Taenidium) are confined to nondepositional surfaces within parallel‐laminated sandstones having parting lineations that represent catastrophically emplaced sand‐sheets in channels and proximal floodplains. Vertical escape burrows are confined to what were slowly but continually accreting parallel‐laminated sands of channel bars. Horizontal dwelling burrows (Palaeophycus) and ‘small stuffed burrows’ are virtually restricted to the smaller sandsheets of floodplain drainage systems.

The burrow assemblages do not occur as recurrent associations throughout the redbed sequence, and variations in different stratigraphic levels seem to be controlled by minor differences within a broadly similar environment. The entire assemblage has components of both the Scoyenia and Rusophycus ichnocoenoses reported from East Greenland but may be considered as the Scoyenia ichnofacies characteristic of redbeds deposited in extensive floodplains dissected by small streams, even though no Scoyenia individuals are present.     

Are pollen fossils useful for calibrating relaxed molecular clock dating of phylogenies? A comparative study using Myrtaceae

The identification and application of reliable fossil calibrations represents a key component of many molecular studies of evolutionary timescales. In studies of plants, most paleontological calibrations are associated with macrofossils. However, the pollen record can also inform age calibrations if fossils matching extant pollen groups are found. Recent work has shown that pollen of the myrtle family, Myrtaceae, can be classified into a number of morphological groups that are synapomorphic with molecular groups. By assembling a data matrix of pollen morphological characters from extant and fossil Myrtaceae, we were able to measure the fit of 26 pollen fossils to a molecular phylogenetic tree using parsimony optimisation of characters. We identified eight Myrtaceidites fossils as appropriate for calibration based on the most parsimonious placements of these fossils on the tree. These fossils were used to inform age constraints in a Bayesian phylogenetic analysis of a sequence alignment comprising two sequences from the chloroplast genome (matK and ndhF) and one nuclear locus (ITS), sampled from 106 taxa representing 80 genera. Three additional analyses were calibrated by placing pollen fossils using geographic and morphological information (eight calibrations), macrofossils (five calibrations), and macrofossils and pollen fossils in combination (12 calibrations). The addition of new fossil pollen calibrations led to older crown ages than have previously been found for tribes such as Eucalypteae and Myrteae. Estimates of rate variation among lineages were affected by the choice of calibrations, suggesting that the use of multiple calibrations can improve estimates of rate heterogeneity among lineages. This study illustrates the potential of including pollen-based calibrations in molecular studies of divergence times.     

New fossils of Australopithecus anamensis from Kanapoi,West Turkana,Kenya (2003–2008)

Renewed fieldwork from 2003 through 2008 at the Australopithecus anamensis type-site of Kanapoi, Kenya, yielded nine new fossils attributable to this species. These fossils all date to between 4.195 and 4.108 million years ago. Most were recovered from the lower fluvial sequence at the site, with one from the lacustrine sequence deltaic sands that overlie the lower fluvial deposits but are still below the Kanapoi Tuff. The new specimens include a partial edentulous mandible, partial maxillary dentition, two partial mandibular dentitions, and five isolated teeth. The new Kanapoi hominin fossils increase the sample known from the earliest Australopithecus, and provide new insights into morphology within this taxon. They support the distinctiveness of the early A. anamensis fossils relative to earlier hominins and to the later Australopithecus afarensis. The new fossils do not appreciably extend the range of observed variation in A. anamensis from Kanapoi, with the exception of some slightly larger molars, and a canine tooth root that is the largest in the hominin fossil record. All of the Kanapoi hominins share a distinctive morphology of the canine–premolar complex, typical early hominin low canine crowns but with mesiodistally longer honing teeth than seen in A. afarensis, and large, probably dimorphic, canine tooth roots. The new Kanapoi specimens support the observation that canine crown height, morphology, root size and dimorphism were not altered from a primitive ape-like condition as part of a single event in human evolution, and that there may have been an adaptive difference in canine function between A. anamensis and A. afarensis.     

When did Cuon reach Java? – Reinvestigation of canid fossils from Homo erectus faunas

The presence of the genus Cuon during the Pleistocene of Java is attested by the endemic species C. sangiranensis and C. crassidens, sometimes classified as C. alpinus, a species that is also part of the Holocene fauna and has persisted until today. The current study revises the fossil canid material from the Sangiran Dome, previously assigned variously to C. sangiranensis, C. crassidens, C. alpinus, C. javanicus, and C. trinilensis. It aims to reinvestigate the arrival of Cuon in Java, in particular in relation to the late early Pleistocene endemic canid of Java: the Cuon-sized Xenocyon trinilensis, which had evolved in situ on Java from the large X. merriami, and which could be a potential competitor to early Cuon in case of contemporaneity. We found that a mandible fragment from Pandejan (holotype of C. crassidens) shows a morphology typical for C. alpinus. However, a maxilla and a mandible from the Bapang Formation at Sangiran, including the holotype of C. sangiranensis, is here assigned to the early dhole species C. priscus. Our results indicate that Cuon was already present in Java during the early middle Pleistocene and probably arrived as part of the immigration events during the Kedung Brubus faunal stage. Since X. trinilensis and Cuon are both hypercarnivorous medium-sized dogs, similar ecological niches are expected for both species. Thus, X. trinilensis probably was outcompeted and replaced by C. priscus. In turn, the latter species was replaced by the extant species, C. alpinus, during the Nangdong faunal stage, likely as part of the next immigration phase, which then disappeared during the tropical rainforest fauna of the Punung faunal stage and re-entered at the onset of the Holocene.     

Upper Triassic (Keuper) non-marine trace fossils from the Haßberge area (Franconia, south-eastern Germany)

Various trace fossils from the Hassberge Formation and the Löwenstein Formation (Middle Keuper, Upper Triassic) of the Haßberge region are described. Twenty-three different forms have been identified, 17 of which are named, includingCruziana pascens n. isp.,Lockeia cunctator n. isp., andRusophycus versans n. isp.Lockeia siliquaria James, 1879,L. amygdaloides (Seilacher, 1953),L. triangulichnus Kim, 1994, andL. elongata (Yang, 1984) are revised and synonymized under the oldest available name,L. siliquaria James, 1879.Rusophycus eutendorfensis (Linck, 1942) andR. carbonarius Dawson, 1864 are revised. The diagnosis ofPolykladichnus Fürsich, 1981 is emended, and a diagnosis forHelminthoidichnites Fitch, 1850 is given for the first time. Among the described ichnotaxa,Skolithos ispp.,Rusophycus carbonarius, andTaenidium barretti are the most common forms. The trace fossil association is typical of theScoyenia ichnofacies, which indicates non-marine, periodically or completely inundated environments, such as floodplains and lake margins. Two palaeoichnocoenoses are identified. One ichnocoenosis, dominated byCruziana problematica, cf.Polykladichnus isp., andSkolithos isp. B characterizes margins of trough cross-bedded sandstones. Another ichnocoenosis, dominated byRusophycus versans n. isp.,Taenidium barretti,Scoyenia gracilis andSkolithos isp. A is related to ephemeral lake deposits. Taxonomic recommendations for the use of hitherto described and figured invertebrate Keuper trace fossils from Germany are given.     

Nothofagus subgenus Brassospora (Nothofagaceae) leaf fossils from New Zealand: a link to Australia and New Guinea?

N othofagus palustris sp. nov. is the first record of well‐preserved leaves of Nothofagus subgenus Brassospora in New Zealand, and is described from an Oligo–Miocene leaf bed in the Gore Lignite Measures of the South Island. Nothofagus palustris is represented by relatively small and variably toothed leaves with cuticular remains that possess all the characteristic features of the subgenus, including the presence of variably sized stomata that are randomly arranged within areoles, hydathodes along the major veins and ‘bulging cells’ within the areoles on the adaxial side. Phylogenetic assessment shows that the leaves are similar to those of Australian Oligocene and Miocene species and may belong to the same clade of Brassospora. Most notably, these species share the derived feature of abundant leaf wax, a feature that is now only well developed in two New Guinean species. This and other evidence allows the possibility that the ancestor of N. palustris reached New Zealand from Australia. However, it is improbable that N. palustris or a similar species was the common ancestor of the clade of Brassospora that is now confined to New Caledonia. Ecologically, N. palustris is unusual among extant and previously described macrofossil species of Brassospora in being found in a relatively open, swampy habitat. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 503–515.