Non-invasive diagnostics in fossils - Magnetic Resonance Imaging of pathological belemnites

Abstract: Abstract. For more than a decade, Magnetic Resonance Imaging (MRI) has been routinely employed in clinical diagnostics because it allows non-invasive studies of anatomical structures and physiological processes in vivo and to differentiate between healthy and pathological states, particularly of soft tissue. Here, we demonstrate that MRI can likewise be applied to fossilized biological samples and help in elucidating paleopathological and paleoecological questions: Five anomalous guards of Jurassic and Cretaceous belemnites are presented along with putative paleopathological diagnoses directly derived from 3D MR images with microscopic resolution. Syn vivo deformities of both the mineralized internal rostrum and the surrounding former soft tissue can be traced back in part to traumatic events of predator-prey-interactions, and partly to parasitism. Besides, evidence is presented that the frequently observed anomalous apical collar might be indicative of an inflammatory disease. These findings highlight the potential of Magnetic Resonance techniques for further paleontological applications.

diagnostic
magnetic resonance imaging
belemnite


The labyrinthine morphology of Pronycticebus gaudryi (Primates, Adapiformes)

Abstract: The publication of a well preserved Eocene primate, Darwinius masillae (Cercamoniinae, Notharctidae), has revived the debate on the phylogenetic relationships of Adapiformes and extant primates (Franzen et al., PLos ONE 4(5):e5723, 2009). Recently, Lebrun et al. (J Anat 216:368-380, 2010) showed that the morphology of the bony labyrinth of strepsirrhine primates conveys a strong phylogenetic signal. The study of labyrinthine morphology may thus bring a new piece of evidence to resolve phylogenetic relationships within a group. The investigation of the labyrinthine morphology of another Cercamoniinae, Pronycticebus gaudryi, reveals no synapomorphy with the labyrinths of modern anthropoids. On the contrary, Pronycticebus is closer in labyrinthine shape to extant strepsirrhines, which supports the hypothesis that the Cercamoniinae and other Adapiformes are the sister group of toothcombed primates.

labyrinthine morphology
morphology
pronycticebus
adapiformes
phylogenetic relationship


Description of a fossil camelid from the Pleistocene of Argentina, and a cladistic analysis of the Camelinae

Abstract: We describe a well-preserved South American Lamini partial skeleton (PIMUZ A/V 4165) from the Ensenadan (~ 1.95-1.77 to 0.4 Mya) of Argentina. The specimen is comprised of a nearly complete skull and mandible with full tooth rows, multiple elements of anterior and posterior limbs, and a scapula. We tested this specimen's phylogenetic position and hypothesized it to be more closely related to Lama guanicoe and Vicugna vicugna than to Hemiauchenia paradoxa. We formulate a hypothesis for the placement of PIMUZ A/V 4165 within Camelinae in a cladistic analysis based on craniomandibular and dental characters and propose that future systematic studies consider this specimen as representing a new species. For the first time in a morphological phylogeny, we code terminal taxa at the species level for the following genera: Camelops, Aepycamelus, Pleiolama, Procamelus, and Alforjas. Our results indicate a divergence between Lamini and Camelini predating the Barstovian (16 Mya). Camelops appears as monophyletic within the Camelini. Alforjas taylori falls out as a basal member of Camelinae-neither as a Lamini nor Camelini. Pleiolama is polyphyletic, with Pleiolama vera as a basal Lamini and Pleiolama mckennai in a more nested position within the Lamini. Aepycamelus and Procamelus are respectively polyphyletic and paraphyletic. Together, they are part of a group of North American Lamini from the Miocene epoch.


Brachiopod faunas, facies and biostratigraphy of the Pridolian to lower Eifelian succession in the Rhenish Massif (Rheinisches Schiefergebirge, Germany)

Abstract: Abstract The succession of Pridolian to lower Eifelian (uppermost Silurian to lowermost Middle Devonian) rhynchonelliformean brachiopod faunas from the Rhenish Massif (Germany) is described and interpreted against the background of sedimentary sequences and facies development. The predominant rhenotypic (‘Rhenish’) facies is redefined as a neritic-siliciclastic facies type of the Devonian. It is subdivided into eurhenotypic, pararhenotypic and allorhenotypic subfacies, based on sedimentary features and specific brachiopod assemblages reflecting different shallow-marine palaeoenvironments under more or less terrigenous influence. The studied sedimentary successions are subdivided biostratigraphically on the basis of brachiopods, correlated on a supraregional scale, and calibrated in terms of the global chronostratigraphy. Stratigraphic intervals with characteristic brachiopod faunas are distinguished. Faunal turnovers between these are attributed to regional events in the context of short or more extended phases of palaeoenvironmental change presumably caused mainly by sea-level fluctuations in combination with varying crustal subsidence and sedimentation rates. These changes resulted in shelf-wide or more regional extinction or emigration of substantial parts of a brachiopod fauna and subsequent replacement by a largely new one. Finally, new taxa of brachiopods are introduced: Sartenaerirhynchus gen. nov., Paraspirifer (Mosellospirifer) subgen. nov., Paraspirifer (Laurentispirifer) subgen. nov., Iridistrophia (Flabellistrophia) subgen. nov. and Iridistrophia (Flabellistrophia) musculosa sp. nov.

pridolian
succession
sedimentary sequence
brachiopod faunas


A new Lagerstätte from the Late Ordovician Big Hill Formation, Upper Peninsula, Michigan

Abstract: A new exceptionally preserved marginal marine biota is reported from the Late Ordovician Big Hill Formation of Stonington Peninsula in Michigan's Upper Peninsula. The new Lagerstätte hosts a moderately diverse fauna of medusae, linguloid brachiopods, non-mineralized arthropods and orthocone nautiloids, alongside dasycladalean green algae. The biota is similar to those of Lagerstätten from the Late Ordovician of Canada, revealing an extensive distribution of a distinctive marginal marine palaeocommunity in Laurentia at this time. The Big Hill biota extends the geographical range of exceptionally preserved Late Ordovician faunas in Laurentia and indicates that further examples remain to be discovered.

new lagerstätte
late ordovician
big hill formation
upper peninsula
biota


The age of the Tiki formation: with remarks on the miofloral succession in the Triassic Gondwanas of India

Abstract:
The age of the Tiki Formation in the South Rewa Gondwana Basin has been discussed. Available data on the vertebrate fauna, megaflora and palynoflora of the Tiki Formation have been evaluated. It is concluded that the Tiki Formation sensu lato (i.e. including the Nidhpuri beds) ranges in age from Anisian through Norian and possibly extends into the Rhaetian.
On the basis of available palynological data an attempt has been made to establish the miofloral succession in the Triassic Gondwanas of India. Presently nine successive palynological zones have been recognized. However, possibility of existence of some more palynological zones is also not ruled out.

tiki formation
miofloral succession
triassic gondwanas


Mouthpart homologies and life habits of Mesozoic long-proboscid scorpionflies

Abstract: Long-proboscid scorpionflies from amber reveal the variety and complexity of mid-Cretaceous pollinating insects. Mesozoic long-proboscid scorpionflies (Mesopsychoidea) provide important clues to ancient plant-pollinator interactions. Among them, the family Aneuretopsychidae is especially important because its mouthparts are vital to deciphering the early evolution of Mesopsychoidea and putatively the origin of fleas (Siphonaptera). However, the identification of mouthpart homologs among Aneuretopsychidae remains controversial because of the lack of three-dimensional anatomical data. Here, we report the first Aneuretopsychidae from Late Cretaceous Burmese amber, which have short maxillary palpi and elongate mouthpart elements consisting of one pair of galeae and one hypopharynx. Their mouthparts are identical to those of Pseudopolycentropodidae (= Dualulidae, new synonym) but are not homologous to those of Siphonaptera. Our phylogenetic analysis provides robust evidence for the debated monophyly of Mesopsychoidea. Our results suggest that the long-proboscid condition has most likely evolved once in Mesopsychoidea, independently from fleas, and further reveal the variety and complexity of mid-Cretaceous pollinating insects.

mesozoic long-proboscid scorpionflie
scorpionflie
mouthpart


Cincinnetina, a new Late Ordovician dalmanellid brachiopod from the Cincinnati type area, USA: implications for the evolution and palaeogeography of the epicontinental fauna of Laurentia

Abstract: Abstract:  The most common forms of Late Ordovician dalmanellid brachiopods from the Cincinnatian type area, previously treated as either Dalmanella or Onniella, are assigned to Cincinnetina gen. nov. The new genus differs from Dalmanella and Onniella in having a consistently developed primary medial costa in the dorsal valve, a larger cardinal process that tends to develop a trilobed myophore, strongly differentiated fine and coarse punctae, and sparse aditicules. Cincinnetina can be distinguished from the closely related Paucicrura and Diceromyonia in its smaller trilobed cardinal process (when developed) that does not have a dominant medial lobe and does not extend into the delthyrial cavity of the ventral valve. Globally, Dalmanella and Onniella occur most commonly in deposits of relatively deep‐ or cool‐water palaeoecological settings, whereas in North America, Cincinnetina, Paucicrura and Diceromyonia are found mainly in carbonate‐rich deposits in warm‐water depositional environments, with Cincinnetina and Paucicrura most common in pericratonic settings and Diceromyonia in palaeoequatorial inland seas.

ordovician dalmanellid brachiopod
brachiopod
cincinnetina


Sources of Heat for Nests of Paleosuchus trigonatus and a Review of Crocodilian Nest Temperatures

Abstract: All species of crocodilian that have been studied normally incubate their eggs at temperatures above 27?C. Stable temperatures above 27?C are not naturally available in the tropical- rainforest habitat of Paleosuchus trigonatus, and our investigations indicate that its nests are not warmed by the processes that have been suggested for nests of other species: insolation, rotting vegetation, and metabolic heat of embryos. Most nests of P. trigonatus are placed at the side of, or on top of, termite mounds. Heat from the termite mound and insulation by the nest material maintain the eggs at about 30?C (28.4-32.1?C).


Skeletal evidence of tuberculosis in a modern identified human skeletal collection (Certosa cemetery, Bologna, Italy).

Abstract: The diagnosis of tuberculosis (TB) in osteoarcheological series relies on the identification of osseous lesions caused by the disease. The study of identified skeletal collections provides the opportunity to investigate the distribution of skeletal lesions in relation to this disease. The aim of this study was to examine the skeletal evidence for TB in late adolescent and adult individuals from the identified human collection of the Certosa cemetery of Bologna (Italy, 19th-20th c.). The sample group consists of 244 individuals (138 males, 106 females) ranging from 17 to 88 years of age. The sample was divided into three groups on the basis of the recorded cause of death: TB (N = 64), pulmonary non-TB (N = 29), and other diseases (N = 151). Skeletal lesions reported to be related to TB were analyzed. The vertebral lesions were classified into three types: enlarged foramina (EnF, vascular foramina with diameter of 3-5 mm), erosions (ER), and other foramina (OtF, cavities of various shapes > 3 mm). A CT scan analysis was also performed on vertebral bodies. Some lesions were seldom present in our sample (e.g., tuberculous arthritis). OtF (23.7%) and subperiosteal new bone formation on ribs (54.2%) are significantly more frequent in the TB group with respect to the other groups. The CT scan analysis showed that the vertebrae of individuals who have died of TB may have internal cavities in the absence of external lesions. These traits represent useful elements in the paleopathological diagnosis of TB.

tuberculosis
skeletal collection
certosa cemetery
identification
paleopathological diagnosis


Explosive morphological diversification of spiny-finned teleost fishes in the aftermath of the end-Cretaceous extinction

Abstract: The spiny-finned teleost fishes (Acanthomorpha) include nearly one-third of all living vertebrate species and assume a bewildering array of bodyplans, but the macroevolutionary assembly of modern acanthomorph biodiversity remains largely unexplored. Here, I reconstruct the trajectory of morphological diversification in this major radiation from its first appearance in the Late Cretaceous to the Miocene using a geometric morphometric database comprising more than 600 extinct species known from complete body fossils. The anatomical diversity (disparity) of acanthomorphs is low throughout the Cretaceous, increases sharply and significantly in the wake of the Cretaceous–Palaeogene (K–P) extinction, and shows little change throughout subsequent Cenozoic intervals. This pattern of morphological diversification appears robust to two potential biasing factors: the ‘Lagerstätten effect’, and the non-random segregation of rare and common taxa along phenotypic axes. Dissecting the trajectory of acanthomorph radiation along phylogenetic lines reveals that the abrupt post-extinction increase in disparity is driven largely by the proliferation of trophically diverse modern groups within Percomorpha, a spiny-fin subclade containing more than 15 000 living species and identified as showing a substantially elevated diversification rate relative to background vertebrate levels. A major component of the Palaeogene acanthomorph radiation reflects colonization of morphospace previously occupied by non-acanthomorph victims of the K–P. However, other aspects of morphological diversification cannot be explained by this simple ecological release model, suggesting that multiple factors contributed to the prolific anatomical radiation of acanthomorphs.

morphological diversification
diversification
spiny-finned teleost fish
acanthomorph


Bayesian phylogenetic estimation of fossil ages

Abstract: Recent advances have allowed for both morphological fossil evidence and molecular sequences to be integrated into a single combined inference of divergence dates under the rule of Bayesian probability. In particular, the fossilized birth–death tree prior and the Lewis-Mk model of discrete morphological evolution allow for the estimation of both divergence times and phylogenetic relationships between fossil and extant taxa. We exploit this statistical framework to investigate the internal consistency of these models by producing phylogenetic estimates of the age of each fossil in turn, within two rich and well-characterized datasets of fossil and extant species (penguins and canids). We find that the estimation accuracy of fossil ages is generally high with credible intervals seldom excluding the true age and median relative error in the two datasets of 5.7% and 13.2%, respectively. The median relative standard error (RSD) was 9.2% and 7.2%, respectively, suggesting good precision, although with some outliers. In fact, in the two datasets we analyse, the phylogenetic estimate of fossil age is on average less than 2 Myr from the mid-point age of the geological strata from which it was excavated. The high level of internal consistency found in our analyses suggests that the Bayesian statistical model employed is an adequate fit for both the geological and morphological data, and provides evidence from real data that the framework used can accurately model the evolution of discrete morphological traits coded from fossil and extant taxa. We anticipate that this approach will have diverse applications beyond divergence time dating, including dating fossils that are temporally unconstrained, testing of the ‘morphological clock', and for uncovering potential model misspecification and/or data errors when controversial phylogenetic hypotheses are obtained based on combined divergence dating analyses. This article is part of the themed issue ‘Dating species divergences using rocks and clocks’.

estimation
fossil age
morphological data
tip


Two ants (Insecta: Hymenoptera: Formicidae: Formicinae) from the Late Pliocene of Willershausen, Germany, with a nomenclatural note on the genus Camponotites

Abstract: Two species of the genus Camponotites (Formicidae, Formicinae) are described from the Late Pliocene deposits of Willershausen, Lower Saxony, northern Germany: C. silvestris Steinbach, 1967, and C. steinbachi n. sp. The generic name Camponotites has been established for fossil (Tertiary) ants independently by Steinbach (Bericht der Naturhistorischen Gesellschaft zu Hannover 111:95-102, 1967) and by Dlussky (Trudy paleontologic ˇeskogo instituta, akademia ˆnauk SSSR, 1981), each for materials of different stratigraphical and geographical origin. Though poorly described, Camponotites Steinbach, 1967, and the single included (type) species C. silvestris Steinbach, 1967 (a monotypic species from the Late Pliocene of Willershausen), were based upon indication in the sense of the ICZN. Therefore, both the generic and specific names are valid and available. Camponotites Dlussky, 1981 (and its type species C. macropterus Dlus- sky, 1981) were certainly introduced correctly and are therefore available, too; but due to its homonymy the generic name is not valid. The revision shows that in this rare case both generic names are not only homonyms but also synonyms.

late pliocene
germany
genus camponotites


Hyoliths and small shelly fossils from the Lower Cambrian of North-East Greenland

Abstract: The hyolith assemblage from the Lower Cambrian Bastion Formation of North-East Greenland is significant in that it contains several hyolith taxa that possess traits of both orders Hyolithida and Orthothecida. They possess morphological traits that seem to be characteristic of the ancestral forms of both groups. In addition, many hyolith taxa from this interval are globally distributed, supporting the notion that these fossils have potential as stratigraphic indicators. This assemblage contains genera and/or species seen in Australia, North America, the Siberian Platform, and South China. Hyoliths identified include the hyolithids Parkula bounites, Hyptiotheca karraculum, Microcornus eximius, M. petilus, Paracornus poulseni gen. et sp. nov., as well as Similotheca similis?, S. bastionensis sp. nov., and S. groenlandica sp. nov.; two opercula remain in open nomenclature. Orthothecids from this assemblage are one unnamed species each of Contitheca and Gracilitheca. Large, macro-sized hyoliths from the same formation described by Poulsen (1932) are mostly unidentifiable, although an operculum formerly identified as Hyolithes (Orthotheca) communis is reassigned to Hyptiotheca. Problematic organisms of uncertain affinity include Cupitheca holocyclata, Conotheca australiensis, an unnamed species of Coleolus, and the cap-shaped Cassitella baculata gen. et sp. nov. that may be an operculum of some as yet unknown organism. Missarzhevsky (1969) used Hyolithes (Orthotheca) bayonet var. groelandicus and H. (O.) bayonet var. longus as the basis for Lenatheca, but the specimens on which that genus is based are too poorly known for a proper diagnosis of Lenatheca.

small shelly fossil
north-east greenland
same formation
hyolith
taxonomy


Increasing morphological complexity in multiple parallel lineages of the Crustacea

Abstract: The prospect of finding macroevolutionary trends and rules in the history of life is tremendously appealing, but very few pervasive trends have been found. Here, we demonstrate a parallel increase in the morphological complexity of most of the deep lineages within a major clade. We focus on the Crustacea, measuring the morphological differentiation of limbs. First, we show a clear trend of increasing complexity among 66 free-living, ordinal-level taxa from the Phanerozoic fossil record. We next demonstrate that this trend is pervasive, occurring in 10 or 11 of 12 matched-pair comparisons (across five morphological diversity indices) between extinct Paleozoic and related Recent taxa. This clearly differentiates the pattern from the effects of lineage sorting. Furthermore, newly appearing taxa tend to have had more types of limbs and a higher degree of limb differentiation than the contemporaneous average, whereas those going extinct showed higher-than-average limb redundancy. Patterns of contemporary species diversity partially reflect the paleontological trend. These results provide a rare demonstration of a large-scale and probably driven trend occurring across multiple independent lineages and influencing both the form and number of species through deep time and in the present day.


Morphological and biomechanical disparity of crocodile-line archosaurs following the end-Triassic extinction

Abstract: Mesozoic crurotarsans exhibited diverse morphologies and feeding modes, representing considerable ecological diversity, yet macroevolutionary patterns remain unexplored. Here, we use a unique combination of morphological and biomechanical disparity metrics to quantify the ecological diversity and trophic radiations of Mesozoic crurotarsans, using the mandible as a morpho-functional proxy. We recover three major trends. First, the diverse assemblage of Late Triassic crurotarsans was morphologically and biomechanically disparate, implying high levels of ecological variation; but, following the end-Triassic extinction, disparity declined. Second, the Jurassic radiation of marine thalattosuchians resulted in very low morphological disparity but moderate variation in jaw biomechanics, highlighting a hydrodynamic constraint on mandibular form. Third, during the Cretaceous terrestrial radiations of neosuchians and notosuchians, mandibular morphological variation increased considerably. By the Late Cretaceous, crocodylomorphs evolved a range of morphologies equalling Late Triassic crurotarsans. By contrast, biomechanical disparity in the Cretaceous did not increase, essentially decoupling from morphology. This enigmatic result could be attributed to biomechanical evolution in other anatomical regions (e.g. cranium, dentition or postcranium), possibly releasing the mandible from selective pressures. Overall, our analyses reveal a complex relationship between morphological and biomechanical disparity in Mesozoic crurotarsans that culminated in specialized feeding ecologies and associated lifestyles.

biomechanical disparity
end-triassic extinction
dentition


A new genus of Devonian tetrapod from North‐East Greenland, with new information on the lower jaw of Ichthyostega

Abstract: Abstract:  A new genus and species of Devonian tetrapod has been identified from material collected in 1947 from the southern slope of Mt. Celsius, Ymer Ø, North‐East Greenland. The specimen preserves both lower jaws, partial palate, premaxillae and maxillae, with a natural mould of parts of the shoulder girdle. The new taxon, Ymeria denticulata, shows differences in dentition, skull ornament and lateral line expression from both Acanthostega and Ichthyostega, but it shows a closer resemblance to the latter. A cladistic analysis not only suggests that Ymeria lies adjacent to Ichthyostega on the tetrapod stem, but also reveals substantial topological instability. As the third genus and the fifth species of tetrapod identified from North‐East Greenland, it demonstrates the high diversity of Devonian tetrapods in that region.


Short-Term Survival of Ammonites in New Jersey After the End-Cretaceous Bolide Impact

Abstract: A section containing the Cretaceous/Paleogene (= Cretaceous/Tertiary) boundary in Monmouth County, New Jersey, preserves a record of ammonites extending from the end of the Cretaceous into possibly the beginning of the Danian. The section includes the upper part of the Tinton Formation and lower part of the Hornerstown Formation. The top of the Tinton Formation is represented by a richly fossiliferous unit (the Pinna Layer) that contains many bivalves in life position as well as ammonite jaws preserved inside body chambers. Ammonites include Pachydiscus (Neodesmoceras) mokotibensis, Sphenodiscus lobatus, Eubaculites carinatus, E. latecarinatus; Discoscaphites iris, D. sphaeroidalis; D. minardi, and D. jerseyensis. The Pinna Layer probably represents a relatively short interval of time lasting tens to hundreds of years; it is conformably overlain by the Burrowed Unit, which contains a single fragment of Discoscaphites sp. and several fragments of E. latecarinatus, as well as several isolated specimens of ammonite jaws including two of Eubaculites. Examination of the mode of preservation of the ammonites and jaws suggests that they were fossilized during deposition of the Burrowed Unit and were not reworked from older deposits. Based on the ammonites and dinoflagellates in the Pinna Layer and the Burrowed Unit, these strata traditionally would be assigned to the uppermost Maastrichtian, corresponding to calcareous nannofossil Subzone CC26b. However, a weak iridium anomaly (500–600 pg/g) is present at the base of the Pinna Layer, which presumably represents the record of the bolide impact. Correlation with the iridium layer at the Global Stratotype Section and Point at El Kef, Tunisia, would, therefore, imply that these assemblages are actually Danian, provided that the iridium anomaly is in place and the ammonites and dinoflagellates are not reworked. If the iridium anomaly is in place, or even if it has migrated downward from the top of the Pinna Layer, the ammonites would have survived the impact at this site for a brief interval of time lasting from a few days to hundreds of years.


Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama

Abstract: Background As we know from modern species, nursery areas are essential shark habitats for vulnerable young. Nurseries are typically highly productive, shallow-water habitats that are characterized by the presence of juveniles and neonates. It has been suggested that in these areas, sharks can find ample food resources and protection from predators. Based on the fossil record, we know that the extinct Carcharocles megalodon was the biggest shark that ever lived. Previous proposed paleo-nursery areas for this species were based on the anecdotal presence of juvenile fossil teeth accompanied by fossil marine mammals. We now present the first definitive evidence of ancient nurseries for C. megalodon from the late Miocene of Panama, about 10 million years ago. Methodology/Principal Findings We collected and measured fossil shark teeth of C. megalodon, within the highly productive, shallow marine Gatun Formation from the Miocene of Panama. Surprisingly, and in contrast to other fossil accumulations, the majority of the teeth from Gatun are very small. Here we compare the tooth sizes from the Gatun with specimens from different, but analogous localities. In addition we calculate the total length of the individuals found in Gatun. These comparisons and estimates suggest that the small size of Gatun's C. megalodon is neither related to a small population of this species nor the tooth position within the jaw. Thus, the individuals from Gatun were mostly juveniles and neonates, with estimated body lengths between 2 and 10.5 meters. Conclusions/Significance We propose that the Miocene Gatun Formation represents the first documented paleo-nursery area for C. megalodon from the Neotropics, and one of the few recorded in the fossil record for an extinct selachian. We therefore show that sharks have used nursery areas at least for 10 millions of years as an adaptive strategy during their life histories.


The hydroid fossil record and analytical techniques for assessing the affinities of putative hydrozoans and possible hemichordates

Abstract: Hydrozoan cnidarians are widespread in modern environments, but their polyps or hydroids, when not biomineralized, are generally rare in the fossil record. To assess the affinities of four hydrozoan taxa previously described on the basis of supposed fossils of non‐biomineralized hydroids, we re‐analysed the type specimens of these taxa using a combination of light and electron microscopic tools, including backscattered electron (BSE) scanning electron microscopy (SEM) and energy‐dispersive X‐ray spectroscopy (EDS). New morphological, ultrastructural and taphonomic data were generated for Archaeoantennularia byersi from the Devonian of Michigan, Archaeocryptolaria compacta from the Ordovician of Virginia, and Mazohydra megabertha and Drevotella proteana from the Carboniferous Mazon Creek Lagerstätte of Illinois, which are preserved as carbonaceous fossils, aluminosilicate films and iron carbonate minerals in siderite concretions, respectively. In the context of these results, we provide a review of the fossil record of non‐biomineralized hydroids, describe possible biases and changes through time in their occurrence and preservation, and evaluate the criteria commonly used to identify and interpret their fossils. Although hydroids have been reported from Phanerozoic (particularly lower Palaeozoic) rocks around the world, many putative hydroids from the Palaeozoic are poorly substantiated and may actually be hemichordates. Indeed, none of the type specimens in this study represent unequivocal hydrozoans. As shown in BSE images, metatype specimens of A. byersi possess autothecae, fusellae, stolons, stolothecae and bithecae, which decisively indicate that they are dendroid graptolites rather than hydroids. The analyses yielded no evidence that A. compacta, Mazohydra and Drevotella are hydrozoans, as their holotypes lack the diagnostic morphological, taphonomic and ecological features characteristic of purported hydroid analogues. Consequently, our results suggest that many Palaeozoic hydroids may be hemichordates and that interpretations of hydroid fossils should be tested and refined using data collected via in situ analytical techniques like BSE‐SEM and EDS.

analytical technique
hydrozoan
hemichordate
fuselli
sem-bse


Introduction to Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia

Abstract: Citation for this article: Sidor, C. A., and S. J. Nesbitt. 2018. Introduction to vertebrate and climatic evolution in the Triassic rift basins of Tanzania and Zambia; pp. 1–7 in C. A. Sidor and S. J. Nesbitt (eds.), Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia. Society of Vertebrate Paleontology Memoir 17. Journal of Vertebrate Paleontology 37 (6, Supplement).


Tooth chipping can reveal the diet and bite forces of fossil hominins

Abstract: Mammalian tooth enamel is often chipped, providing clear evidence for localized contacts with large hard food objects. Here, we apply a simple fracture equation to estimate peak bite forces directly from chip size. Many fossil hominins exhibit antemortem chips on their posterior teeth, indicating their use of high bite forces. The inference that these species must have consumed large hard foods such as seeds is supported by the occurrence of similar chips among known modern-day seed predators such as orangutans and peccaries. The existence of tooth chip signatures also provides a way of identifying the consumption of rarely eaten foods that dental microwear and isotopic analysis are unlikely to detect.

bite force
fossil hominin
hard food
tooth chipping


Abstract: During the late Messinian post evaporitic phase, in the eastern region between the Alps and the Aral Sea, the Paratethys was reduced to a number of large independent basins (Pannonian Basin, Pontic Basin and Caspian-Aral Basin) separated by vast continental regions. At the same time, in the Paleomediterranean region, discontinuous shallow-water basins were formed on the existing substrate. In these basins predominantly siliciclastic sediments were deposited consisting of gravels, sands, marls and silts, and containing continental oligohaline faunas. These sedimentary facies, which are largely exposed in Italy and in other Mediterranean regions, are called "Lago-Mare". These sediments overlapping the Messinian evaporitic layers in apparent conformity have already been reported from western Sicily. Now they have been sampled and analyzed in five different localities in eastern Sicily. These sedimentary facies are called "Congeria" strata (marl containing oligohaline faunas) and "Arenazzolo" (reddish arkosic sands containing brackish or freshwater ostracods). From these levels, which correspond to two different sedimentation environments, an oligotypic ostracod fauna was extracted consisting of species belonging to the genera Tyrrhenocythere, Loxoconcha and Cyprideis. Among them, Loxoconcha muelleri (Mehes, 1908) and Cyprideis anlavauxensis Carbonnel, 1979, are reported for the first time from Sicily. Two other species are new to science; one is described as Tyrrhenocythere pulcherrima sp. nov. herein, whereas, the other one is left in open nomenclature as Loxoconcha n. sp. Francesco Sciuto. Department of Biological, Geological and Environmental Science, University of Catania, Corso Italia 55, 95129 Catania, Italy. fsciuto@unict.it Angela Baldanza. Department of Physics and Geology, University of Perugia, Via Pascoli, 06123 Perugia, Italy. angela.baldanza@unipg.it Rim Temani. Office National des Mines, 24, rue de l'énergie, 2035 La Charguia, Tunis, Tunisia. rim.temani@yahoo.fr Giovanni Privitera. Technical Study of Energy and Environment, Via Municipio, Misterbianco, Catania. giovpriv@tim.it http://zoobank.org/DA7F28E3-631B-4F93-B5B9-91A4B6CAB46E Sciuto, Francesco, Baldanza, Angela, Temani, Rim, and Privitera, Giovanni. 2018. New reports of Paratethyan ostracods affinity from the Mediterranean Basin (Sicily, Italy). Palaeontologia Electronica 21.1.12A 1-19. https://doi.org/10.26879/800 palaeo-electronica.org/content/2018/2174-paratethyan-ostracods Copyright: April 2018 Palaeontological Association. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ SCIUTO ET AL.: PARATETHYAN OSTRACODS

paratethyan ostracod affinity
ostracod affinity
mediterranean basin


The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida)

Abstract: Crown group Archosauria, which includes birds, dinosaurs, crocodylomorphs, and several extinct Mesozoic groups, is a primary division of the vertebrate tree of life. However, the higher-level phylogenetic relationships within Archosauria are poorly resolved and controversial, despite years of study. The phylogeny of crocodile-line archosaurs (Crurotarsi) is particularly contentious, and has been plagued by problematic taxon and character sampling. Recent discoveries and renewed focus on archosaur anatomy enable the compilation of a new dataset, which assimilates and standardizes character data pertinent to higher-level archosaur phylogeny, and is scored across the largest group of taxa yet analysed. This dataset includes 47 new characters (25% of total) and eight taxa that have yet to be included in an analysis, and total taxonomic sampling is more than twice that of any previous study. This analysis produces a well-resolved phylogeny, which recovers mostly traditional relationships within Avemetatarsalia, places Phytosauria as a basal crurotarsan clade, finds a close relationship between Aetosauria and Crocodylomorpha, and recovers a monophyletic Rauisuchia comprised of two major subclades. Support values are low, suggesting rampant homoplasy and missing data within Archosauria, but the phylogeny is highly congruent with stratigraphy. Comparison with alternative analyses identifies numerous scoring differences, but indicates that character sampling is the main source of incongruence. The phylogeny implies major missing lineages in the Early Triassic and may support a Carnian-Norian extinction event.

phylogeny
archosauria
avemetatarsalia
terrestrial ecological niche


Early human dispersals within the Americas

Abstract: Complex processes in the settling of the Americas The expansion into the Americas by the ancestors of present day Native Americans has been difficult to tease apart from analyses of present day populations. To understand how humans diverged and spread across North and South America, Moreno-Mayar et al. sequenced 15 ancient human genomes from Alaska to Patagonia. Analysis of the oldest genomes suggests that there was an early split within Beringian populations, giving rise to the Northern and Southern lineages. Because population history cannot be explained by simple models or patterns of dispersal, it seems that people moved out of Beringia and across the continents in a complex manner. Science, this issue p. eaav2621 Ancient genomes from the Americas show a complex genetic history giving rise to present-day diversity. INTRODUCTION Genetic studies of the Pleistocene peopling of the Americas have focused on the timing and number of migrations from Siberia into North America. They show that ancestral Native Americans (NAs) diverged from Siberians and East Asians ~23,000 years (~23 ka) ago and that a split within that ancestral lineage between later NAs and Ancient Beringians (ABs) occurred ~21 ka ago. Subsequently, NAs diverged into northern NA (NNA) and southern NA (SNA) branches ~15.5 ka ago, a split inferred to have taken place south of eastern Beringia (present-day Alaska and western Yukon Territory). RATIONALE Claims of migrations into the Americas by people related to Australasians or by bearers of a distinctive cranial morphology (“Paleoamericans”) before the divergence of NAs from Siberians and East Asians have created controversy. Likewise, the speed by which the Americas were populated; the number of basal divergences; and the degrees of isolation, admixture, and continuity in different regions are poorly understood. To address these matters, we sequenced 15 ancient human genomes recovered from sites spanning from Alaska to Patagonia; six are ≥10 ka old (up to ~18× coverage). RESULTS All genomes are most closely related to NAs, including those of two morphologically distinct Paleoamericans and an AB individual. However, we also found that the previous model is just a rough outline of the peopling process: NA dispersal gave rise to more complex serial splitting and early population structure—including that of a population that diverged before the NNA-SNA split—as well as admixture with an earlier unsampled population, which is neither AB nor NNA or SNA. Once in the Americas, SNAs spread widely and rapidly, as evidenced by genetic similarity, despite differences in material cultural, between >10-ka-old genomes from North and South America. Soon after arrival in South America, groups diverged along multiple geographic paths, and before 10.4 ka ago, these groups admixed with a population that harbored Australasian ancestry, which may have been widespread among early South Americans. Later, Mesoamerican-related population(s) expanded north and south, possibly marking the movement of relatively small groups that did not necessarily swamp local populations genetically or culturally. CONCLUSION NAs radiated rapidly and gave rise to multiple groups, some visible in the genetic record only as unsampled populations. At different times these groups expanded to different portions of the continent, though not as extensively as in the initial peopling. That the early population spread widely and rapidly suggests that their access to large portions of the hemisphere was essentially unrestricted, yet there are genomic and archaeological hints of an earlier human presence. How these early groups are related or structured, particularly those with Australasian ancestry, remains unknown. Rapid expansion, compounded by the attenuating effect of distance and, in places, by geographic and social barriers, gave rise to complex population histories. These include strong population structure in the Pacific Northwest; isolation in the North American Great Basin, followed by long-term genetic continuity and ultimately an episode of admixture predating ~0.7 ka ago; and multiple independent, geographically uneven migrations into South America. One such migration provides clues of Late Pleistocene Australasian ancestry in South America, whereas another represents a Mesoamerican-related expansion; both contributed to present-day South American ancestry. NA dispersal and divergence over time. Schematic representation of the sampling points included in this study (circles) and our main conclusions (presented geographically and temporally). (A) Population history of the basal AB, NNA, and SNA branches in North America. kya, thousand years ago. (B) Early, rapid dispersal of SNAs across the continent (~14 ka ago). (C) Recent Mesoamerican-related expansion north and south. Arrows do not correspond to specific migration routes. Studies of the peopling of the Americas have focused on the timing and number of initial migrations. Less attention has been paid to the subsequent spread of people within the Americas. We sequenced 15 ancient human genomes spanning from Alaska to Patagonia; six are ≥10,000 years old (up to ~18× coverage). All are most closely related to Native Americans, including those from an Ancient Beringian individual and two morphologically distinct “Paleoamericans.” We found evidence of rapid dispersal and early diversification that included previously unknown groups as people moved south. This resulted in multiple independent, geographically uneven migrations, including one that provides clues of a Late Pleistocene Australasian genetic signal, as well as a later Mesoamerican-related expansion. These led to complex and dynamic population histories from North to South America.


Ontogenetic stages of ceratopsian dinosaur Psittacosaurus
in bone histology

Abstract: The early ceratopsians Psittacosaurus and Protoceratops have provided important information on dinosaurian development because of abundant specimens of adults, subadults, juveniles, and even hatchlings. Here we present new data and methods for identifying key growth stages from bone histology. Previous studies on Psittacosaurus lujiatunensis from the Early Cretaceous Jehol Biota of China did not present in-depth analysis of growth patterns. Based on a histological study of 43 thin sections from 17 individuals of this species, we recognize four histological ontogenetic stages, i.e., hatchling, juvenile, sub-adult, and adult, but no fully-grown stage. We estimate life history and longevity from diaphyseal growth line counts and other features of histology. We show that P. lujiatunensis grew fast in early stages (hatchling, juvenile, and subadult), according to the density of vascular canals and the different type of bone tissue; the deposition of parallel fibred bone tissue in the outer cortex of the subadult stage indicates that growth rate was slowing down. We introduce a new graphical method to estimate the occurrence and volumes of vascular canals from thin sections more accurately than current two-dimensional approaches.

bone histology
psittacosaurus lujiatunensis
ontogenetic stage


Hominin and animal activities in the microstratigraphic record from Denisova Cave (Altai Mountains, Russia)

Abstract: Denisova Cave in southern Siberia uniquely contains evidence of occupation by a recently discovered group of archaic hominins, the Denisovans, starting from the middle of the Middle Pleistocene. Artefacts, ancient DNA and a range of animal and plant remains have been recovered from the sedimentary deposits, along with a few fragmentary fossils of Denisovans, Neanderthals and a first-generation Neanderthal–Denisovan offspring. The deposits also contain microscopic traces of hominin and animal activities that can provide insights into the use of the cave over the last 300,000 years. Here we report the results of a micromorphological study of intact sediment blocks collected from the Pleistocene deposits in the Main and East Chambers of Denisova Cave. The presence of charcoal attests to the use of fire by hominins, but other evidence of their activities preserved in the microstratigraphic record are few. The ubiquitous occurrence of coprolites, which we attribute primarily to hyenas, indicates that the site was visited for much of its depositional history by cave-dwelling carnivores. Microscopic traces of post-depositional diagenesis, bioturbation and incipient cryoturbation are observed in only a few regions of the deposit examined here. Micromorphology can help identify areas of sedimentary deposit that are most conducive to ancient DNA preservation and could be usefully integrated with DNA analyses of sediments at archaeological sites to illuminate features of their human and environmental history that are invisible to the naked eye.


The evolution of biramous appendages revealed by a carapace-bearing Cambrian arthropod

Abstract: Biramous appendages are a common feature among modern marine arthropods that evolved deep in arthropod phylogeny. The branched appendage of Cambrian arthropods has long been considered as the ancient biramous limb, sparking numerous investigations on its origin and evolution. Here, we report a new arthropod, Erratus sperare gen. et sp. nov., from the Lower Cambrian (Stage 3, 520 Ma) Chengjiang biota of Yunnan, China, with unique trunk appendages formed of lateral anomalocaridid-type flaps and ventral subconical endopods. These appendages represent an intermediate stage of biramous limb evolution, i.e. from ‘two pairs of flap appendages' in radiodonts to ‘flap + endopod’ in Erratus, to ‘exopod + endopod’ in the rest of carapace-bearing arthropods that populate the basal region of the upper-stem lineage arthropods (deuteropods). The new species occupies a phylogenetic position at the first node closer to deuteropods than to radiodonts, and therefore pinpoints the earliest occurrence of the endopod within Deuteropoda. The primitive endopod is weakly sclerotized, and has unspecialized segments without endites or claw. The findings might support previous claims that the outer branch of the biramous limb of fossil marine arthropods, such as trilobites, is not a true exopod, but is instead a modified exite. This article is part of the theme issue ‘The impact of Chinese palaeontology on evolutionary research’.

biramous appendage
cambrian arthropod
chengjiang biota


The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary

Abstract: The Fall of the Dinosaurs According to the fossil record, the rule of dinosaurs came to an abrupt end ∼65 million years ago, when all nonavian dinosaurs and flying reptiles disappeared. Several possible mechanisms have been suggested for this mass extinction, including a large asteroid impact and major flood volcanism. Schulte et al. (p. 1214) review how the occurrence and global distribution of a global iridium-rich deposit and impact ejecta support the hypothesis that a single asteroid impact at Chicxulub, Mexico, triggered the extinction event. Such an impact would have instantly caused devastating shock waves, a large heat pulse, and tsunamis around the globe. Moreover, the release of high quantities of dust, debris, and gases would have resulted in a prolonged cooling of Earth's surface, low light levels, and ocean acidification that would have decimated primary producers including phytoplankton and algae, as well as those species reliant upon them. The Cretaceous-Paleogene boundary ~65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction. Notably, a single ejecta-rich deposit compositionally linked to the Chicxulub impact is globally distributed at the Cretaceous-Paleogene boundary. The temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations (for example, darkness and cooling) lead us to conclude that the Chicxulub impact triggered the mass extinction.

mass extinction
cretaceous-paleogene boundary
volcanism
terrestrial ecosystem
eruption


Abstract: Nguyen, J.M.T., Boles, W.E., Worthy, T.H., Hand, S.J. & Archer, M., 2014. New specimens of the logrunner Orthonyx kaldowinyeri (Passeriformes: Orthonychidae) from the Oligo-Miocene of Australia. Alcheringa 38, 000–000. ISSN 0311–5518. Logrunners (Orthonychidae) are a family of ground-dwelling passerines that are endemic to the Australo-Papuan region. These peculiar birds are part of an ancient Australo-Papuan radiation that diverged basally in the oscine tree. Here we describe eight fossil tarsometatarsi of the logrunner Orthonyx kaldowinyeri, and a distal tibiotarsus tentatively assigned to this species from sites in the Riversleigh World Heritage Area, Australia. The new fossil material ranges in age from late Oligocene to early late Miocene, and extends the temporal range of the Orthonychidae into the late Oligocene; this is the geologically oldest record of the family. These specimens also include the oldest Cenozoic passerine fossils from Australia that can be confidently referred to an extant family. The distinctive features of the tarsometatarsus and tibiotarsus of extant logrunners, which are probably related to their unusual method of foraging, are also present in O. kaldowinyeri. Assuming that O. kaldowinyeri had vegetation requirements similar to those of extant logrunners, its presence in various Riversleigh sites provides clues about the palaeoenvironment of these sites. Jacqueline M.T. Nguyen [jacqueline.nguyen@unsw.edu.au] (author for correspondence), Suzanne J. Hand [s.hand@unsw.edu.au], Michael Archer [m.archer@unsw.edu.au], School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Walter E. Boles [walter.boles@austmus.gov.au], Ornithology Section, Australian Museum, 6 College Street, Sydney, NSW 2010, Australia; Trevor H. Worthy [trevor.worthy@flinders.edu.au], School of Biological Sciences, Flinders University, Adelaide, SA 5001, Australia. Received 19.9.2013; revised 11.10.2013; accepted 25.10.2013 http://zoobank.org/urn:lsid:zoobank.org:pub:F4F6219A-22A3-4F6B-8AEE-2957A227C0E0


Palaeobiological inferences of the aetosaur Aetosauroides scagliai (Archosauria: Pseudosuchia) based on microstructural analyses of its appendicular bones

Abstract: ABSTRACT Aetosaurs were a group of armoured pseudosuchians, recorded in most of the Upper Triassic continental deposits worldwide. Several osteohistological contributions of aetosaurs focused on their osteoderms, but rarely on appendicular bones. Here, we analyse the microstructure of the humerus, femur and tibia of Aetosauroides scagliai (specimens PVL 2073 [holotype] and PVL 2052). These exhibit cortical bone formed by highly vascularised fibrolamellar bone present in the inner portion of the cortex, mixed with scarce parallel-fibred bone. Also, they show parallel-fibred bone in the outermost portion of the cortex. A general growth pattern that includes a first rapid stage followed by a slow stage is reported. Nevertheless, the growth rate and the presence of parallel-fibred bone embedded in fibrolamellar bone layers recognise more variation within Aetosauria. The value of appendicular bones and osteoderms as age estimators is variable, the first being useful in early stages, and in late stages the osteoderms are better (based on the particular growth of osteoderms). Through morphological (neurocentral sutures) and histological (EFS absent) information, the holotype (PVL 2073) was recovered between juvenile and subadult stages. Using a statistical model that combines microanatomical and morphological data, a terrestrial lifestyle is inferred for Aetosauroides, which concur with previous analyses.

aetosauroides scagliai
appendicular bone
pseudosuchian


Permian Brachiopods of West Texas, VI

Abstract: G. Arthur Cooper and Richard E. Grant. Permian Brachiopods of West Texas, I. Smithsonian Contributions to Paleobiology, number 14, 231 pages, 39 figures, 23 plates, 1972.—The first of a projected six-part monograph on the brachiopods of the reference area for the North American Permian in the Glass, Guadalupe, Diablo, Delaware, Hueco, and Chinati Mountains of West Texas and adjacent New Mexico, this introductory volume recounts the history of geological work in the area, the development of the stratigraphic framework in the Wolf camp, Leonard, and Guadalupe Series, and the basis for age assignments. It also explains field and laboratory techniques for collecting and preparing silicified fossils by means of acid, and it presents detailed measurements and lithic descriptions of the stratigraphic units in each mountain range in terms of the current nomenclature. The paleoecologic implications of the various rock and fossil types are interpreted, and the problems concerning large scale conglomerates, bioherms, and shell heaps are considered. T h e faunal composition of each stratigraphic unit in each mountain range is set forth as documentation for a local zonation of the brachiopods, intra-regional correlations, and age determinations with reference to the worldwide time scale for the Permian. There are brief accounts of each locality from which fossils were obtained. The full locality listing and the literature cited for the entire monograph are included in the present volume. Plates and line drawings illustrate the techniques of collecting and preparing fossils and the nature of certain stratigraphic units and lithic types; they diagrammatically depict numerous cross sections and correlations. Detailed maps indicate the exact positions of collections of fossils in the Glass Mountains. Taxonomic descriptions will appear in subsequent volumes. Official publication date is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. Library of Congress Cataloging in Publication Data Cooper, Gustav Arthur, 1902Permian brachiopods of West Texas (Smithsonian contributions to paleobiology, no. 14) Bibliography: v. 1, p. 1. Brachiopoda, Fossil. 2. Paleontology—Permian. 3. Paleontology—Texas. I. Grant, Richard E., joint author. II. Title. III. Scries: Smithsonian Institution. Smithsonian contributions to paleobiology, no. 14 QE701.S56 no. 14 [QE796] 560'.8s [564'.8'097649] 72-4218 For sale by the Superintendent of Documents, U. S. Government Printing Office Washington, D. C 20402 Price |2.25 (paper cover)


Mollusks from the upper Shackleton Limestone (Cambrian Series 2), Central Transantarctic Mountains, East Antarctica

Abstract:
Abstract.
 An assemblage of Cambrian Series 2, Stages 3–4, conchiferan mollusks from the Shackleton Limestone, Transantarctic Mountains, East Antarctica, is formally described and illustrated. The fauna includes one bivalve, one macromollusk, and 10 micromollusks, including the first description of the species Xinjispira simplex Zhou and Xiao, 1984 outside North China. The new fauna shows some similarity to previously described micromollusks from lower Cambrian glacial erratics from the Antarctic Peninsula. The fauna,mainly composed of steinkerns, is relatively low diversity, but the presence of diagnostic taxa, including helcionelloid Davidonia rostrata (Zhou and Xiao, 1984), bivalve Pojetaia runnegari Jell, 1980, cambroclavid Cambroclavus absonus Conway Morris in Bengtson et al., 1990, and bradoriid Spinospitella coronata Skovsted et al., 2006, as well as the botsfordiid brachiopod Schizopholis yorkensis (Ushatinskaya and Holmer in Gravestock et al., 2001), in the overlying Holyoake Formation correlates the succession to the Dailyatia odyssei Zone (Cambrian Stages 3–4) in South Australia.

shackleton limestone
transantarctic mountains
mollusk


Danian cold-water corals from the Baunekule facies, Faxe Formation, Denmark: a rare taphonomic window of a coral mound flank habitat

Abstract: Well-preserved cold-water corals are comparatively rare in the fossil record. This is partly due to the very low fossilization potential of the predominantly aragonitic corals but also due to the fact that coral ecosystems of deep water are a geologically young development. A Middle Danian cold-water coral mound complex is well exposed in Faxe Quarry, Denmark. The coral mounds are intercalated with bryozoan mounds of various sizes and form the Faxe Formation. The coral limestone displays large variations in diagenesis, and this complicates the palaeoecological reconstructions. However, the Baunekule facies from the Faxe Formation contain a well-preserved originally aragonitic and calcitic fauna. The aragonitic skeletons have been recrystallized to calcite during early diagenesis and the excellent preservation makes taxonomic identifications straightforward. A diverse fauna of ten scleractinian coral species, nine stylasterine coral species and seven octocoral species has been described from the Baunekule facies. The fossil fauna represents an ecological niche between the dead coral framework and coral rubble on a flank of a growing Dendrophyllia coral mound with multiple colonization events. The diversity and relative abundance of the fossil scleractinian corals are comparable to the modern settings in the NE Atlantic and Mediterranean. The distribution and diversity of the octocorals and the stylasterine corals are suggested to represent coral gardens as described from modern setting in the NE Pacific. The presence of a diverse and abundant stylasterine fauna suggests a stable palaeoenvironment, probably in a bathymetric depth range of 200–400 metre.


Radiocarbon dating casts doubt on the late chronology of the Middle to Upper Palaeolithic transition in southern Iberia

Abstract: It is commonly accepted that some of the latest dates for Neanderthal fossils and Mousterian industries are found south of the Ebro valley in Iberia at ca. 36 ka calBP (calibrated radiocarbon date ranges). In contrast, to the north of the valley the Mousterian disappears shortly before the Proto-Aurignacian appears at ca. 42 ka calBP. The latter is most likely produced by anatomically modern humans. However, two-thirds of dates from the south are radiocarbon dates, a technique that is particularly sensitive to carbon contaminants of a younger age that can be difficult to remove using routine pretreatment protocols. We have attempted to test the reliability of chronologies of 11 southern Iberian Middle and early Upper Paleolithic sites. Only two, Jarama VI and Zafarraya, were found to contain material that could be reliably dated. In both sites, Middle Paleolithic contexts were previously dated by radiocarbon to less than 42 ka calBP. Using ultrafiltration to purify faunal bone collagen before radiocarbon dating, we obtain ages at least 10 ka 14C years older, close to or beyond the limit of the radiocarbon method for the Mousterian at Jarama VI and Neanderthal fossils at Zafarraya. Unless rigorous pretreatment protocols have been used, radiocarbon dates should be assumed to be inaccurate until proven otherwise in this region. Evidence for the late survival of Neanderthals in southern Iberia is limited to one possible site, Cueva Antón, and alternative models of human occupation of the region should be considered.

southern iberia
pretreatment protocol
radiocarbon


Abstract: WHITE, M.A., FALKINGHAM, P.L., COOK, A.G., HOCKNULL, S.A. & ELLIOTT, D.A., 2013. Morphological comparisons of metacarpal I for Australovenator wintonensis and Rapator ornitholestoides: implications for their taxonomic relationships. Alcheringa 37, 1 - 7. ISSN 0311-5518. Various comparisons of left metacarpal I of the Australovenator wintonensis holotype have been made with Rapator ornitholestoides. These specimens were identified as being morphologically more similar than either was to that of the neovenatorid Megaraptor namunhuaiquii. Owing to the poor preservation of A. wintonensis and R. ornitholestoides, distinct morphological separation between the two appeared minimal. The recent discovery of a near perfectly preserved right metacarpal I of A. wintonensis enables a direct and accurate comparison with R. ornitholestoides. Distinct morphological differences exist between the metacarpals of the two species. A re-evaluation of the age of the A. wintonensis holotype site (AODL 85 ‘Matilda Site’) with zircon dating reveals a maximum age of 95 Ma, 10 Ma younger than the Griman Creek Formation at Lightning Ridge, from which R. ornitholestoides was recovered. This age difference detracts from the probability that the specimens belong to the same genus. Matt A. White∗ [fossilised@hotmail.com], School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia; Peter L. Falkingham† [pfalkingham@rvc.ac.uk], Department of Comparative Biomedical Sciences, Structure and Motion Laboratory, Royal Veterinary College, London, UK; Alex G. Cook [alex.cook@y7mail.com] and Scott A. Hocknull [scott.hocknull@qm.qld.gov.au], Ancient environments, Queensland Museum, Hendra, Queensland, 4011, Australia; David A. Elliott [david.elliott@aaod.com.au], Australian Age of Dinosaurs Museum of Natural History, The Jump Up, Winton, Queensland, 4735, Australia. ∗Also affiliated with Australian Age of Dinosaurs Museum of Natural History, The Jump Up, Winton, Queensland 4735, Australia. †Also affiliated with Department of Ecology and Evolutionary Biology, Division of Biology and Medicine, Brown University, USA. Received 22.9.2012; revised 13.1.2013; accepted 17.1.2013.

metacarpal
australovenator wintonensis
taxonomic relationship
australia


History and contemporary significance of the Rhynie cherts—our earliest preserved terrestrial ecosystem

Abstract: The Rhynie cherts Unit is a 407 million-year old geological site in Scotland that preserves the most ancient known land plant ecosystem, including associated animals, fungi, algae and bacteria. The quality of preservation is astonishing, and the initial description of several plants 100 years ago had a huge impact on botany. Subsequent discoveries provided unparalleled insights into early life on land. These include the earliest records of plant life cycles and fungal symbioses, the nature of soil microorganisms and the diversity of arthropods. Today the Rhynie chert (here including the Rhynie and Windyfield cherts) takes on new relevance, especially in relation to advances in the fields of developmental genetics and Earth systems science. New methods and analytical techniques also contribute to a better understanding of the environment and its organisms. Key discoveries are reviewed, focusing on the geology of the site, the organisms and the palaeoenvironments. The plants and their symbionts are of particular relevance to understanding the early evolution of the plant life cycle and the origins of fundamental organs and tissue systems. The Rhynie chert provides remarkable insights into the structure and interactions of early terrestrial communities, and it has a significant role to play in developing our understanding of their broader impact on Earth systems. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

terrestrial ecosystem
land
late silurian
vascular land plant
diversification


Time‐averaging and fidelity of modern death assemblages: building a taphonomic foundation for conservation palaeobiology

Abstract: Ecosystems today are under growing pressure, with human domination at many scales. It is difficult, however, to gauge what has changed or been lost – and why – in the absence of data from periods before human activities. Actualistic taphonomic studies, originally motivated to understand preservational controls on deep‐time fossil records, are now providing insights into modern death assemblages as historical archives of present‐day ecosystems, turning taphonomy on its head. This article reviews the past 20 years of work on the temporal resolution and ability of time‐averaged skeletal assemblages to capture ecological information faithfully, focusing primarily on molluscs from soft‐sediment seafloors. Two promising arenas for ‘applied taphonomy’ are then highlighted: (1) using live‐dead mismatch – that is, observed discordance in the diversity, species composition, and distribution of living animals and co‐occurring skeletal remains – to recognize recent anthropogenic change, and (2) using time‐averaged death assemblages as windows into regional diversity and long‐term baselines, as a supplement or substitute for conventional live‐collected data. Meta‐analysis and modelling find that, in unaltered habitats, live‐dead differences in community‐level attributes can be generated largely or entirely by time‐averaging of natural spatial and temporal variability in living assemblages, on time frames consistent with the range of shell ages observed in death assemblages. Time‐averaging coarsens the temporal and spatial resolution of biological information in predictable ways; by comparison, taphonomic bias of information arising from differential preservation, production and transport of shells is surprisingly modest. Several challenges remain for basic taphonomic research, such as empirical and analytical methods of refining the temporal resolution of death assemblages; assessing the fate of resolution and fidelity with progressive burial; and expanding our understanding of the dynamics of skeletal accumulation in other groups and settings. Rather than shunning human‐impacted areas as inappropriate analogues of the deep past, we should capitalize on them to explore the fundamental controls on skeletal accumulation and to develop robust protocols for bringing time‐averaged death assemblages into the toolkits of conservation biology and environmental management.

fidelity
death assemblage
accumulation
time‐averaging
fossil assemblage


Origin of ecdysis: fossil evidence from 535-million-year-old scalidophoran worms

Abstract: With millions of extant species, ecdysozoans (Scalidophora, Nematoida and Panarthropoda) constitute a major portion of present-day biodiversity. All ecdysozoans secrete an exoskeletal cuticle which must be moulted periodically and replaced by a larger one. Although moulting (ecdysis) has been recognized in early Palaeozoic panarthropods such as trilobites and basal groups such as anomalocaridids and lobopodians, the fossil record lacks clear evidence of ecdysis in early scalidophorans, largely because of difficulties in recognizing true exuviae. Here, we describe two types of exuviae in microscopic scalidophoran worms from the lowermost Cambrian Kuanchuanpu Formation (ca 535 Ma) of China and reconstruct their moulting process. These basal scalidophorans moulted in a manner similar to that of extant priapulid worms, extricating themselves smoothly from their old tubular cuticle or turning their exuviae inside out like the finger of a glove. This is the oldest record of moulting in ecdysozoans. We also discuss the origin of ecdysis in the light of recent molecular analyses and the significance of moulting in the early evolution of animals.

ecdysis
scalidophoran worm
panarthropoda
cambrian kuanchuanpu formation
old record


Reacquisition of the lower temporal bar in sexually dimorphic fossil lizards provides a rare case of convergent evolution

Abstract: Temporal fenestration has long been considered a key character to understand relationships amongst reptiles. In particular, the absence of the lower temporal bar (LTB) is considered one of the defining features of squamates (lizards and snakes). In a re-assessment of the borioteiioid lizard Polyglyphanodon sternbergi (Cretaceous, North America), we detected a heretofore unrecognized ontogenetic series, sexual dimorphism (a rare instance for Mesozoic reptiles), and a complete LTB, a feature only recently recognized for another borioteiioid, Tianyusaurus zhengi (Cretaceous, China). A new phylogenetic analysis (with updates on a quarter of the scorings for P. sternbergi) indicates not only that the LTB was reacquired in squamates, but it happened independently at least twice. An analysis of the functional significance of the LTB using proxies indicates that, unlike for T. zhengi, this structure had no apparent functional advantage in P. sternbergi, and it is better explained as the result of structural constraint release. The observed canalization against a LTB in squamates was broken at some point in the evolution of borioteiioids, whereas never re-occuring in other squamate lineages. This case of convergent evolution involves a mix of both adaptationist and structuralist causes, which is unusual for both living and extinct vertebrates.

lizard
convergent evolution
low temporal bar


Carnivorous mammals from the middle Eocene Washakie Formation, Wyoming, USA, and their diversity trajectory in a post-warming world

Abstract: The middle Eocene Washakie Formation of Wyoming, USA, provides a rare window, within a single depositional basin, into the faunal transition that followed the early Eocene warming events. Based on extensive examination, we report a minimum of 27 species of carnivorous mammals from this formation, more than doubling the previous taxic count. Included in this revised list are a new species of carnivoraform, Neovulpavus mccarrolli n. sp., and up to ten other possibly new taxa. Our cladistic analysis of early Carnivoraformes incorporating new data clarified the array of middle Eocene taxa that are closely related to crown-group Carnivora. These anatomically relatively derived carnivoraforms collectively had an intercontinental distribution in North America and east Asia, exhibiting notable variations in body size and dental adaptation. This time period also saw parallel trends of increase in body size and dental sectoriality in distantly related lineages of carnivores spanning a wide range of body sizes. A new, model-based Bayesian analysis of diversity dynamics accounting for imperfect detection revealed a high probability of substantial loss of carnivore species between the late Bridgerian and early Uintan North American Land Mammal 'Ages', coinciding with the disappearance of formerly common mammals such as hyopsodontids and adapiform primates. Concomitant with this decline in carnivore diversity, the Washakie vertebrate fauna underwent significant disintegration, as measured by patterns of coordinated detection of taxa at the locality level. These observations are consistent with a major biomic transition in the region in response to climatically induced opening-up of forested habitats. UUID: http://zoobank.org/9162f1a6-a12c-4d55-ba1d-dc66e8cda261


Extended Y chromosome investigation suggests postglacial migrations of modern humans into East Asia via the northern route.

Abstract: Genetic diversity data, from Y chromosome and mitochondrial DNA as well as recent genome-wide autosomal single nucleotide polymorphisms, suggested that mainland Southeast Asia was the major geographic source of East Asian populations. However, these studies also detected Central-South Asia (CSA)- and/or West Eurasia (WE)-related genetic components in East Asia, implying either recent population admixture or ancient migrations via the proposed northern route. To trace the time period and geographic source of these CSA- and WE-related genetic components, we sampled 3,826 males (116 populations from China and 1 population from North Korea) and performed high-resolution genotyping according to the well-resolved Y chromosome phylogeny. Our data, in combination with the published East Asian Y-haplogroup data, show that there are four dominant haplogroups (accounting for 92.87% of the East Asian Y chromosomes), O-M175, D-M174, C-M130 (not including C5-M356), and N-M231, in both southern and northern East Asian populations, which is consistent with the proposed southern route of modern human origin in East Asia. However, there are other haplogroups (6.79% in total) (E-SRY4064, C5-M356, G-M201, H-M69, I-M170, J-P209, L-M20, Q-M242, R-M207, and T-M70) detected primarily in northern East Asian populations and were identified as Central-South Asian and/or West Eurasian origin based on the phylogeographic analysis. In particular, evidence of geographic distribution and Y chromosome short tandem repeat (Y-STR) diversity indicates that haplogroup Q-M242 (the ancestral haplogroup of the native American-specific haplogroup Q1a3a-M3) and R-M207 probably migrated into East Asia via the northern route. The age estimation of Y-STR variation within haplogroups suggests the existence of postglacial (∼18 Ka) migrations via the northern route as well as recent (∼3 Ka) population admixture. We propose that although the Paleolithic migrations via the southern route played a major role in modern human settlement in East Asia, there are ancient contributions, though limited, from WE, which partly explain the genetic divergence between current southern and northern East Asian populations.


Effects of CO2 and Ocean Mixing on Miocene and Pliocene Temperature Gradients

Abstract: Cenozoic climate changes have been linked to tectonic activity and variations in atmospheric CO2 concentrations. Here, we present Miocene and Pliocene sensitivity experiments performed with the climate model COSMOS. The experiments contain changes with respect to paleogeography, ocean gateway configuration, and atmospheric CO2 concentrations, as well as a range of vertical mixing coefficients in the ocean. For the mid‐Miocene, we show that the impact of ocean mixing on surface temperature is comparable to the effect of the possible range in reconstructed CO2 concentrations. In combination with stronger vertical mixing, relatively moderate CO2 concentrations of 450 ppmv enable global‐mean surface, deep‐water, and meridional temperature characteristics representative of mid‐Miocene Climatic Optimum (MMCO) reconstructions. The Miocene climate shows a reduced meridional temperature gradient and reduced seasonality. In the case of enhanced mixing, surface and deep ocean temperatures show significant warming of up to 5–10°C and an Arctic temperature anomaly of >12°C. In the Pliocene simulations, the impact of vertical mixing and CO2 is less important for the deep ocean, which we interpret as a different sensitivity dependence on the background state and mixed layer dynamics. We find a significant reduction in surface albedo and effective emissivity for either a high level of atmospheric CO2 or increased vertical mixing. Our mixing sensitivity experiments provide a warm deep ocean via ocean heat uptake. We propose that the mixing hypothesis can be tested by reconstructions of the thermocline and seasonal paleoclimate data indicating a lower seasonality relative to today.

ocean mixing
miocene
warming
arctic temperature anomaly


Feeding preferences of Gomphotherium subtapiroideum (Proboscidea, Mammalia) from the Miocene of Sandelzhausen (Northern Alpine Foreland Basin, southern Germany) through life and geological time: evidence from dental microwear analysis

Abstract: The objective of this study is to estimate changes in feeding preferences of the proboscidean species Gomphotherium subtapiroideum (Schlesinger 1917) by means of dental microwear analyses. The dietary changes are first evaluated through the ontogeny of this species, between juveniles and adults, and are then studied through geological time, from early Middle Miocene (MN5) to middle Late Miocene (MN8-9) localities of the German Molasse Basin. The microwear patterns of juvenile and adult individuals of G. subtapiroideum from Sandelzhausen (MN5) differ merely by the variable ''length of scratches'', emphasizing longer jaw movements during mastication in adults. The microwear signatures of G. subtapiroideum do not vary significantly between the two geological time periods studied, but reflect mixed feeding preferences in both cases. These results imply that, despite an important environmental change at that time (drying and opening), the ecology of G. subtapiroideum and, especially, its feeding habits were not affected. Its dental microwear pattern is then compared with those of other species of Proboscidea from the Middle-Late Miocene of Germany, namely Deinotherium giganteum and Gomphotherium steinheimense.

germany
geological time
dental microwear analysis


Old Lineages in a New Ecosystem: Diversification of Arcellinid Amoebae (Amoebozoa) and Peatland Mosses

Abstract: Arcellinid testate amoebae (Amoebozoa) form a group of free-living microbial eukaryotes with one of the oldest fossil records known, yet several aspects of their evolutionary history remain poorly understood. Arcellinids occur in a range of terrestrial, freshwater and even brackish habitats; however, many arcellinid morphospecies such as Hyalosphenia papilio are particularly abundant in Sphagnum-dominated peatlands, a relatively new ecosystem that appeared during the diversification of Sphagnum species in the Miocene (5–20 Myr ago). Here, we reconstruct divergence times in arcellinid testate amoebae after selecting several fossils for clock calibrations and then infer whether or not arcellinids followed a pattern of diversification that parallels the pattern described for Sphagnum. We found that the diversification of core arcellinids occurred during the Phanerozoic, which is congruent with most arcellinid fossils but not with the oldest known amoebozoan fossil (i.e. at ca. 662 or ca. 750 Myr). Overall, Sphagnum and the Hyalospheniidae exhibit different patterns of diversification. However, an extensive molecular phylogenetic analysis of distinct clades within H. papilio species complex demonstrated a correlation between the recent diversification of H. papilio, the recent diversification of Sphagnum mosses, and the establishment of peatlands.


Early Jurassic diversification of pycnodontiform fishes (Actinopterygii, Neopterygii) after the end-Triassic extinction event: evidence from a new genus and species, Grimmenodon aureum

Abstract:
ABSTRACT
 A new genus and species of pycnodontiform fishes, Grimmenodon aureum, from marginal marine, marinebrackish lower Toarcian (Harpoceras exaratum ammonite subzone) clay deposits of Grimmen in northeastern Germany is described. The single specimen represents a diagnostic left prearticular dentition characterized by unique tooth arrangement and ornamentation patterns. Grimmenodon aureum, gen. et sp. nov., is the second unambiguously identified pycnodontiform species from the Early Jurassic, in addition to Eomesodon liassicus from the early Lower Jurassic of western Europe. We also report an indeterminate pycnodontiform tooth crown from the upper Pliensbachian (Pleuroceras apyrenum ammonite subzone) of the same site. The material expands the Early Jurassic range of pycnodontiforms significantly northwards and confirms their presence before and immediately following the onset of the Toarcian Oceanic Anoxic Event (T-OAE) in the marginal marine ecosystems south of the Fennoscandian Shield. Moreover, the new records indicate that the Early Jurassic diversity of pycnodontiform fishes was greater than previously assumed and probably equaled that of the Late Triassic. Therefore, it is hypothesized that the Triassic-Jurassic mass extinction event did not affect pycnodontiform fishes significantly. Micro-computed tomography was used to study the internal anatomy of the prearticular of Grimmenodon aureum, gen. et sp. nov. Our results show that no replacement teeth were formed within the tooth-bearing bone but rather were added posteriorly to functional teeth.

pycnodontiform fish
new genus
grimmenodon aureum
upper pliensbachian


Abstract: Brea, M., Zamuner, A.B., Matheos, S.D., Iglesias, A. & Zucol, A.F., December, 2008. Fossil wood of the Mimosoideae from the early Paleocene of Patagonia, Argentina. Alcheringa 32, 427–441. ISSN 0311-5518. An anatomically preserved mature stem from the Salamanca Formation (early Paleocene) at Palacio de Los Loros, central Patagonia, Argentina, is described and assigned to Paracacioxylon frenguellii sp. nov. The material was preserved by siliceous permineralization and shows features of the secondary xylem typical of subfamily Mimosoideae. This species represents the oldest record of the genus and of the Leguminosae along the western border of Gondwana, and is the world's second oldest record of Leguminosae wood. The species is characterized by ring-porous to semi-ring-porous vessels that are solitary, in multiples of 2–4 and clustered, simple perforation plates, alternate and vestured inter-vessel pitting, homocellular 1–6 seriate rays, tyloses, crystals and diffuse apotracheal, vasicentric paratracheal and confluent axial parenchyma. Paracacioxylon frenguellii has anatomical similarities to Acacia Miller. The presence of Paracacioxylon frenguellii associated with pulvinate leaves suggests that the legumes might have been a component of mesothermal forests developed along the western margin of the Golfo San Jorge Basin during the early Paleocene.

mimosoideae
paleocene
salamanca formation
fossil wood


Megalancosaurus, a possibly arboreal archosauromorph (Reptilia) from the Upper Triassic of northern Italy

Abstract: ABSTRACT The Late Triassic reptile Megalancosaurus preonensis Calzavara et al., 1980, was previously known from a single incomplete specimen collected from the Norian “Dolomia di Forni” at the locality of val Preone, near Ampezzo Carnico (Udine, Friuli, northern Italy). The recent discovery of a new specimen in the Zorzino Limestone, also of Norian age, at a locality near Zogno (Bergamo Prealps, Lombardy, northern Italy) allows a more complete description of the skeleton of Megalancosaurus preonensis and attribution of three other specimens, previously interpreted as juvenile individuals of Drepanosaurus unguicaudatus to the same taxon. Megalancosaurus was a small reptile with a high degree of adaptation toward arboreal life, and is probably an archosauromorph.

archosauromorph
northern italy
megalancosaurus


A new phylogenetic hypothesis of turtles with implications for the timing and number of evolutionary transitions to marine lifestyles in the group

Abstract: Evolutionary transitions to marine habitats occurred frequently among Mesozoic reptiles. Only one such clade survives to the present: sea turtles (Chelonioidea). Other marine turtles originated during the Mesozoic, but uncertain affinities of key fossils have obscured the number of transitions to marine life, and the timing of the origin of marine adaptation in chelonioids. Phylogenetic studies support either a highly‐inclusive chelonioid total‐group including fossil marine clades from the Jurassic and Cretaceous (e.g. protostegids, thalassochelydians, sandownids) or a less inclusive chelonioid total‐group excluding those clades. Under this paradigm, these clades belong outside Cryptodira, and represent at least one additional evolutionary transition to marine life in turtles. We present a new phylogenetic hypothesis informed by high resolution computed tomographic data of living and fossil taxa. Besides a well‐supported Chelonioidea, which includes protostegids, we recover a previously unknown clade of stem‐group turtles, Angolachelonia, which includes the Late Jurassic thalassochelydians, and the Cretaceous–Palaeogene sandownids. Accounting for the Triassic Odontochelys, our results indicate three independent evolutionary transitions to marine life in non‐pleurodiran turtles (plus an additional two‐three in pleurodires). Among all independent origins of marine habits, a pelagic ecology only evolved once, among chelonioids. All turtle groups that independently invaded marine habitats in the Jurassic–Cretaceous (chelonioids, angolachelonians, bothremydid pleurodires) survived the Cretaceous–Palaeogene mass extinction event. This highlights extensive survival of marine turtles compared to other marine reptiles. Furthermore, deeply‐nested clades such as chelonioids are found by the middle Early Cretaceous, suggesting a rapid diversification of crown‐group turtles during the Early Cretaceous.

new phylogenetic hypothesis
turtle
evolutionary transition
chelonioidea
ecology


Illustrating phylogenetic placement of fossils using RoguePlots: An example from ichneumonid parasitoid wasps (Hymenoptera, Ichneumonidae) and an extensive morphological matrix

Abstract: The fossil record constitutes the primary source of information about the evolutionary history of extant and extinct groups, and many analyses of macroevolution rely on fossils that are accurately placed within phylogenies. To avoid misinterpretation of the fossil record, especially by non-palaeontologists, the proper assessment and communication of uncertainty in fossil placement is crucial. We here use Bayesian morphological phylogenetics to evaluate the classifications of fossil parasitoid wasps (Hymenoptera, Ichneumonidae) and introduce ‘RoguePlots’ to illustrate placement uncertainty on the phylogeny of extant taxa. Based on an extensive, newly constructed morphological matrix of 222 characters in 24 fossil and 103 extant taxa, we test three different aspects of models of morphological evolution. We find that a model that includes ordered characters, among-character rate variation, and a state-space restricted to observed states achieves the highest marginal likelihoods. The individual RoguePlots reveal large differences in confidence in the placement of the different fossils and allow some refinements to their classification: Polyhelictes bipolarus and Ichninsum appendicrassum are moved from an uncertain subfamily placement to Pimplinae, Plectiscidea lanhami is transferred to Allomacrus in Cylloceriinae (Allomacrus lanhami, comb. nov.), Lithotorus cressoni is moved from Diplazontinae to Orthocentrinae, and we note uncertainty in the generic placements of Rhyssella? vera and Xanthopimpla? messelensis. We discuss potential artefacts that might result in biased posterior probabilities in Bayesian morphological phylogenetic analyses, pertaining to character and taxon sampling, fossilization biases, and model misspecification. Finally, we suggest future directions both in ichneumonid palaeontology and in the way RoguePlots can improve both assessment and representation of placement uncertainty, both in fossils and other rogue taxa.

parasitoid wasp
hymenoptera
morphological matrix
taxon sampling


Powered flight in hatchling pterosaurs: evidence from wing form and bone strength

Abstract: Competing views exist on the behaviour and lifestyle of pterosaurs during the earliest phases of life. A ‘flap-early’ model proposes that hatchlings were capable of independent life and flapping flight, a ‘fly-late’ model posits that juveniles were not flight capable until 50% of adult size, and a ‘glide-early’ model requires that young juveniles were flight-capable but only able to glide. We test these models by quantifying the flight abilities of very young juvenile pterosaurs via analysis of wing bone strength, wing loading, wingspan and wing aspect ratios, primarily using data from embryonic and hatchling specimens of Pterodaustro guinazui and Sinopterus dongi. We argue that a young Sinopterus specimen has been mischaracterised as a distinct taxon. The humeri of pterosaur juveniles are similar in bending strength to those of adults and able to withstand launch and flight; wing size and wing aspect ratios of young juveniles are also in keeping with powered flight. We therefore reject the ‘fly-late’ and ‘glide-early’ models. We further show that young juveniles were excellent gliders, albeit not reliant on specialist gliding. The wing forms of very young juveniles differ significantly from larger individuals, meaning that variation in speed, manoeuvrability, take-off angle and so on was present across a species as it matured. Juveniles appear to have been adapted for flight in cluttered environments, in contrast to larger, older individuals. We propose on the basis of these conclusions that pterosaur species occupied distinct niches across ontogeny.


Appraisal of the fossil record of Homarus (nephropid lobster), with description of a new species from the upper Oligocene of Hungary and remarks on the status of Hoploparia

Abstract:
Abstract.
 The fossil record of the clawed lobster genus, Homarus, is appraised. The taxonomic history of Homarus and Hoploparia is summarized, and a list of species recognized for each is provided. A tabulation of all fossil species of the family Nephropidae permits assessment of nephropid species diversity through time. A new species of Homarus, H. hungaricus, is recorded from the upper Oligocene (Chattian) Mány Formation at Mány, northern Hungary. The species is known by a single specimen consisting of a partial cephalothorax, a pleon minus telson, and partial chelipeds. Homarus is now known by two extant species (H. americanus and H. gammarus) and six fossil taxa, one of Early Cretaceous (Albian; H. benedeni) and five of Cenozoic age (H. hungaricus n. sp., H. klebsi, H. lehmanni, H. morrisi, and H. percyi). The new fossil Homarus differs from modern congeners in aspects of carapace and pleon ornamentation and, especially, cutter claw shape. This is the fourth Oligocene occurrence of a nephropid species; all are Homarus and all are from Western Europe. Homarus makes its appearance in the fossil record in the Early Cretaceous (Albian) and then is not known again until the Paleogene, despite the fact that nephropid lobsters in general are well known from the Late Cretaceous. Nephropid lobsters are better known from the Cretaceous than from the Cenozoic. Both raw species numbers and numbers corrected (normalized) for epicontinental sea coverage show that shelf-dwelling nephropid lobsters were most diverse during the Late Cretaceous.

nephropid lobster
upper oligocene
hoploparia


Romundina and the evolutionary origin of teeth

Abstract: Theories on the origin of vertebrate teeth have long focused on chondrichthyans as reflecting a primitive condition—but this is better informed by the extinct placoderms, which constitute a sister clade or grade to the living gnathostomes. Here, we show that ‘supragnathal’ toothplates from the acanthothoracid placoderm Romundina stellina comprise multi-cuspid teeth, each composed of an enameloid cap and core of dentine. These were added sequentially, approximately circumferentially, about a pioneer tooth. Teeth are bound to a bony plate that grew with the addition of marginal teeth. Homologous toothplates in arthrodire placoderms exhibit a more ordered arrangement of teeth that lack enameloid, but their organization into a gnathal, bound by layers of cellular bone associated with the addition of each successional tooth, is the same. The presence of enameloid in the teeth of Romundina suggests that it has been lost in other placoderms. Its covariation in the teeth and dermal skeleton of placoderms suggests a lack of independence early in the evolution of jawed vertebrates. It also appears that the dentition—manifest as discrete gnathal ossifications—was developmentally discrete from the jaws during this formative episode of vertebrate evolution.

placoderm
tooth
bony plate
romundina
dermal jaw bone


Antiquity of cleptoparasitism among bees revealed by morphometric and phylogenetic analysis of a Paleocene fossil nomadine (Hymenoptera: Apidae)

Abstract: Cleptoparasitism is a way of life involving the theft of resources by one animal from another. This behaviour occurs in many bee tribes but its origin and evolution remain obscure, particularly owing to the relative scarcity of bees in the fossil record. Hitherto, no fossil evidence has been recorded to trace the origin of cleptoparasitim among bees. In the current study, we present the first cleptoparasitic bee fossil, providing analyses of its taxonomic affinities and a complete description. The specimen also happens to be one of the earliest bee fossils, having been discovered in the spongo‐diatomitic volcanic paleolake of Menat (Paleocene) in France. We employed geometric morphometrics of the forewing shape to assess the taxonomic affinities of the fossil with modern apoid tribes. Our dataset included 979 specimens representing 50 tribes and 225 extant species. Based on linear and geometric morphometrics, we demonstrate that the fossil's forewing shape is similar to that of Apidae, and particularly to that of the tribe Epeolini (Nomadinae). The fossil is described as Paleoepeolus micheneri gen.n., sp.n. and provides the first direct evidence on the antiquity of cleptoparasitism among bees.

cleptoparasitism
bee
apidae
forewing shape