Extinct Order Research Articles

†Bittacopsocus-a new bizarre genus of †Permopsocida (Insecta) from Burmese Cretaceous amber.

A new insect species (†Bittacopsocus megacephalus Beutel, Prokop, Müller et Pohl gen. et sp. nov.) is described, based on a single small male (ca. 2.5 mm) embedded in mid Cretaceous Burmese amber. The species shows some resemblance with the mecopteran family Bittacidae, mainly due to strongly elongated and thin legs. However, the structural affinities are apparently due to convergency. Different features, but especially the mouthparts and the pattern of wing venation, indicate that the species belongs to the extinct order †Permopsocida (?Archipsyllidae). However, it differs markedly from all species previously described in this extinct group. The very thin and strongly elongated legs are probably autapomorphic. A very unusual feature is the antenna with only seven segments and extremely elongated flagellomeres. The two pairs of wings are unusually narrow. M and CuA are basally fused. Proximal rows of spines, two series of closed cells, and a distinctly increased number of terminal branches of M are present in the forewings, in contrast to other archipsyllid genera. It is conceivable that Bittacopsocus megacephalus used its long legs to rest suspended in the vegetation like Bittacus. The head structures tentatively suggest predatory behavior but the feeding habits are unclarified yet.

A Piranha-like Pycnodontiform Fish from the Late Jurassic

Pycnodontiformes are an extinct order of ray-finned fishes from the Triassic to Eocene [1, 2], with a characteristic crushing dentition reflecting a highly specialized diet [3]. However, our discovery of a new pycnodontiform from the Late Jurassic (ca.152 Ma) Plattenkalk deposits of the Solnhofen Archipelago revealed long, pointed teeth along the vomer and triangular teeth with cutting edges along the prearticulars. This is the earliest evidence of specialized flesh cutting in a ray-finned fish. The dentition pattern, tooth shape, jaw morphology, and mechanics are all indicative of a feeding apparatus suitable for slicing flesh or fins, thus pioneering a new ecological niche. Evidence suggests that it may have exploited aggressive mimicry in a striking parallel to the feeding patterns of modern piranha. Remarkably, fossil fishes recovered from the same deposits as the new pycnodontiform show injuries to fins and fin bases. As a marine piranha-like fish contemporary with dinosaurs, it is the oldest known flesh-eating actinopterygian, revealing remarkable convergent evolution with modern piranhas.

Early African Fossils Elucidate the Origin of Embrithopod Mammals

Modern mammals rapidly evolved in the early Cenozoic in all continental provinces, including in Africa, with one of the first placental branches, the Afrotheria [1, 2]. Afrotherian evolution is at the origin of the major radiation of African ungulate-like mammals, including extant hyrax, elephant, and sea cow orders, which all belong to the Paenungulata. The paenungulate radiation also includes the extinct order Embrithopoda of uncertain interordinal relationships, which is best known forthe giant and strangely specialized Oligocene genus Arsinoitherium. The Ouled Abdoun basin, Morocco, yielded exceptional Paleocene-Eocene fossils documenting the early paenungulate evolution [3-8]. Here we report two new small Ypresian species, Stylolophus minor n.g., n.sp. and cf. Stylolophus sp., which are the earliest and most primitive embrithopods. The cladistic analysis relates the Embrithopoda to crown paenungulates as the stem-group of the Tethytheria, which makes crown tethytherians restricted to extant elephant and sea cow orders. The Embrithopoda is therefore an early tethytherian offshoot predating the elephant and sea cow divergence. The resulting phylogeny supports a strictly African early radiation of the paenungulates excluding the Phenacolophidae and Anthracobunia. It sustains an at least early Paleocene African origin of the Embrithopoda. The unique tooth pattern of the embrithopods (hyperdilambdodont and pseudolophodont molars) is resolved as evolving early and directly from thedilambdodont (W-shaped labial molar crests) ancestral paenungulate morphotype. The specialized upper molar morphology with two transverse crests is convergent and non-homologous in embrithopods and crown Tethytheria. These convergences for specialized folivorous diet were driven by free herbivorous African niches in the early Paleogene.

Predicting ecosystem vulnerability to biodiversity loss from community composition.

Ecosystems vary widely in their responses to biodiversity change, with some losing function dramatically while others are highly resilient. However, generalizations about how species- and community-level properties determine these divergent ecosystem responses have been elusive because potential sources of variation (e.g., trophic structure, compensation, functional trait diversity) are rarely evaluated in conjunction. Ecosystem vulnerability, or the likely change in ecosystem function following biodiversity change, is influenced by two types of species traits: response traits that determine species' individual sensitivities to environmental change, and effect traits that determine a species' contribution to ecosystem function. Here we extend the response-effect trait framework to quantify ecosystem vulnerability and show how trophic structure, within-trait variance, and among-trait covariance affect ecosystem vulnerability by linking extinction order and functional compensation. Using in silico trait-based simulations we found that ecosystem vulnerability increased when response and effect traits positively covaried, but this increase was attenuated by decreasing trait variance. Contrary to expectations, in these communities, both functional diversity and trophic structure increased ecosystem vulnerability. In contrast, ecosystem functions were resilient when response and effect traits covaried negatively, and variance had a positive effect on resiliency. Our results suggest that although biodiversity loss is often associated with decreases in ecosystem functions, such effects are conditional on trophic structure, and the variation within and covariation among response and effect traits. Taken together, these three factors can predict when ecosystems are poised to lose or gain function with ongoing biodiversity change.

Redefining the extinct orders Miomoptera and Hypoperlida as stem acercarian insects

BackgroundThe systematic positions of the extinct insect orders Hypoperlida, Miomoptera and Permopsocida were enigmatic and unstable for nearly a century. The recent studies based on new material, especially from the Cenomanian Burmese amber, shed light on evolutionary history of Acercaria resolving Permopsocida as the stem group of Condylognatha. However, the knowledge of the remaining two orders differs significantly.ResultsIn this study, we describe new specimens and evaluate morphology of various structures with emphasis on the mouthparts and wing venation. Our results are primary based on revisions of the type specimens with a proper delimitation of taxa Hypoperlida and Miomoptera followed by their significance for the evolutionary history of Acercaria. Three new genera as Belmomantis gen. nov., Elmomantis gen. nov., and Mazonopsocus gen. nov. are designated as members of Palaeomanteidae. The Pennsylvanian Mazonopsocus provides a minimum age for calibration, in accordance to the presence of crown acercarians during the late Carboniferous.ConclusionsThis contribution demonstrates that Hypoperlida and Miomoptera are stem groups of Acercaria. The putative clade (Hypoperlida + Miomoptera) is appearing as potential sister group of (Psocodea + (Permopsocida + (Thripida + Hemiptera))).

The dental phenotype of hairless dogs with FOXI3 haploinsufficiency

Hairless dog breeds show a form of ectodermal dysplasia characterised by a lack of hair and abnormal tooth morphology. This has been attributed to a semi-dominant 7-base-pair duplication in the first exon of the forkhead box I3 gene (FOXI3) shared by all three breeds. Here, we identified this FOXI3 variant in a historical museum sample of pedigreed hairless dog skulls by using ancient DNA extraction and present the associated dental phenotype. Unlike in the coated wild type dogs, the hairless dogs were characterised in both the mandibular and maxillary dentition by a loss of the permanent canines, premolars and to some extent incisors. In addition, the deciduous fourth premolars and permanent first and second molars consistently lacked the distal and lingual cusps; this resulted in only a single enlarged cusp in the basin-like heel (talonid in lower molars, talon in upper molars). This molar phenotype is also found among several living and fossil carnivorans and the extinct order Creodonta in which it is associated with hypercarnivory. We therefore suggest that FOXI3 may generally be involved in dental (cusp) development within and across mammalian lineages including the hominids which are known to exhibit marked variability in the presence of lingual cusps.

Dead But Not Gone: Contemporary Legacies of Communism, Imperialism, and Authoritarianism

A profusion of recent research has focused on historical legacies as key to understanding contemporary outcomes. We review this body of research, analyzing both the comparative-historical analysis (CHA) and modern political economy (MPE) research traditions as applied to the study of communism, imperialism, and authoritarianism. We restrict our focus to the sizeable subset of arguments that meets a relatively strict definition of legacies, i.e., arguments that locate the roots of present-day outcomes in causal factors operative during an extinct political order. For all their differences, the CHA and MPE approaches both face the challenges of convincingly identifying the sources of historical persistence and of reckoning with alternative channels of causation. We find that mechanisms of persistence in legacy research generally belong to one of three main categories. While both traditions acknowledge the role of institutions in historical persistence, CHA research tends to emphasize the lasting power of coalitions, whereas work in MPE often argues for the persistence of cognitions. We argue that, at their best, CHA and MPE approaches yield complementary insights. Further progress in legacy research will benefit from greater cross-fertilization across research traditions and deeper recognition of commonalities across communist, imperialist, and authoritarian regimes.

Dead But Not Gone: Contemporary Legacies of Communism, Imperialism, and Authoritarianism

A profusion of recent research has focused on historical legacies as key to understanding contemporary outcomes. We review this body of research, analyzing both the comparative-historical analysis (CHA) and modern political economy (MPE) research traditions as applied to the study of communism, imperialism, and authoritarianism. We restrict our focus to the sizeable subset of arguments that meets a relatively strict definition of legacies, i.e., arguments that locate the roots of present-day outcomes in causal factors operative during an extinct political order. For all their differences, the CHA and MPE approaches both face the challenges of convincingly identifying the sources of historical persistence and of reckoning with alternative channels of causation. We find that mechanisms of persistence in legacy research generally belong to one of three main categories. While both traditions acknowledge the role of institutions in historical persistence, CHA research tends to emphasize the lasting power of coalitions, whereas work in MPE often argues for the persistence of cognitions. We argue that, at their best, CHA and MPE approaches yield complementary insights. Further progress in legacy research will benefit from greater cross-fertilization across research traditions and deeper recognition of commonalities across communist, imperialist, and authoritarian regimes.

Ontogenetic and life history trait changes associated with convergent ecological specializations in extinct ungulate mammals

Investigating life history traits in mammals is crucial to understand their survival in changing environments. However, these parameters are hard to estimate in a macroevolutionary context. Here we show that the use of dental ontogenetic parameters can provide clues to better understand the adaptive nature of phenotypic traits in extinct species such as South American notoungulates. This recently extinct order of mammals evolved in a context of important geological, climatic, and environmental variations. Interestingly, notoungulates were mostly herbivorous and acquired high-crowned teeth very early in their evolutionary history. We focused on the variations in crown height, dental eruption pattern, and associated body mass of 69 notoungulate taxa, placed in their phylogenetic and geological contexts. We showed that notoungulates evolved higher crowns several times between 45 and 20 Ma, independently of the variation in body mass. Interestingly, the independent acquisitions of ever-growing teeth were systematically accompanied by eruption of molars faster than permanent premolars. These repeated associations of dental innovations have never been documented for other mammals and raise questions on their significance and causal relationships. We suggest that these correlated changes could originate from ontogenetic adjustments favored by structural constraints, and may indicate accelerated life histories. Complementarily, these more durable and efficient dentitions could be selected to cope with important ingestions of abrasive particles in the context of intensified volcanism and increasing aridity. This study demonstrates that assessing both life history and ecological traits allows a better knowledge of the specializations of extinct mammals that evolved under strong environmental constraints.

The relationships of Gasteroclupea branisai Signeux, 1964, a freshwater double-armored herring (Clupeomorpha, Ellimmichthyiformes) from the Late Cretaceous-Paleocene of South America

The clupeomorph fish Gasteroclupea branisai Signeux, 1964 from the Late Cretaceous-Paleocene of El Molino Formation, Cayara locality, Bolivia is redescribed in detail. This South American double-armored herring is the sole member of the family Gasteroclupeidae and exhibits a unique combination of features (skull roof ornamented with fine tubercles, beryciform foramen, endopterygoid teeth, about 16–18 supraneurals, a series of 35–38 predorsal and 40 ventral scutes, median fins small and containing 12–14 rays) that clearly supports its assignment to the extinct clupeomorph order Ellimmichthyiformes. G. branisai shares a number of synapomorphies with Sorbinichthys elusivo and S. africanus (five hypurals, second hypural autogenous, distal end of the second uroneural not reaching the distal end of the first uroneural) with which it forms a monophyletic assemblage recognized herein for the first time as the new suborder Sorbinichthyoidei. The peculiar morphology of Gasteroclupea that is characterized by having an extremely deep abdominal profile, hypertrophied coracoid, and elongated pectoral fins, resembles in many aspects the body plan of extant freshwater hatchetfishes of the characiform family Gasteropelecidae, suggesting that the morphological adaptations of G. branisai can be related, at least in part, to a similar lifestyle.

The Skull of Epidolops ameghinoi from the Early Eocene Itabora\xed Fauna, Southeastern Brazil, and the Affinities of the Extinct Marsupialiform Order Polydolopimorphia

The skull of the polydolopimorphian marsupialiform Epidolops ameghinoi is described in detail for the first time, based on a single well-preserved cranium and associated left and right dentaries plus additional craniodental fragments, all from the early Eocene (53–50 million year old) Itaboraí fauna in southeastern Brazil. Notable craniodental features of E. ameghinoi include absence of a masseteric process, very small maxillopalatine fenestrae, a prominent pterygoid fossa enclosed laterally by a prominent ectopterygoid crest, an absent or tiny transverse canal foramen, a simple, planar glenoid fossa, and a postglenoid foramen that is immediately posterior to the postglenoid process. Most strikingly, the floor of the hypotympanic sinus was apparently unossified, a feature found in several stem marsupials but absent in all known crown marsupials. “Type II” marsupialiform petrosals previously described from Itaboraí plausibly belong to E. ameghinoi; in published phylogenetic analyses, these petrosals fell outside (crown-clade) Marsupialia. “IMG VII” tarsals previously referred to E. ameghinoi do not share obvious synapomorphies with any crown marsupial clade, nor do they resemble those of the only other putative polydolopimorphians represented by tarsal remains, namely the argyrolagids. Most studies have placed Polydolopimorphia within Marsupialia, related to either Paucituberculata, or to Microbiotheria and Diprotodontia. However, diprotodonty almost certainly evolved independently in polydolopimorphians, paucituberculatans and diprotodontians, and Epidolops does not share obvious synapomorphies with any marsupial order. Epidolops is dentally specialized, but several morphological features appear to be more plesiomorphic than any crown marsupial. It seems likely Epidolops that falls outside Marsupialia, as do morphologically similar forms such as Bonapartherium and polydolopids. Argyrolagids differ markedly in their known morphology from Epidolops but share some potential apomorphies with paucituberculatans. It is proposed that Polydolopimorphia as currently recognised is polyphyletic, and that argyrolagids (and possibly other taxa currently included in Argyrolagoidea, such as groeberiids and patagoniids) are members of Paucituberculata. This hypothesis is supported by Bayesian non-clock phylogenetic analyses of a total evidence matrix comprising DNA sequence data from five nuclear protein-coding genes, indels, retroposon insertions, and morphological characters: Epidolops falls outside Marsupialia, whereas argyrolagids form a clade with the paucituberculatans Caenolestes and Palaeothentes, regardless of whether the Type II petrosals and IMG VII tarsals are used to score characters for Epidolops or not. There is no clear evidence for the presence of crown marsupials at Itaboraí, and it is possible that the origin and early evolution of Marsupialia was restricted to the “Austral Kingdom” (southern South America, Antarctica, and Australia).

Relationships of the species of Armigatus (Clupeomorpha, Ellimmichthyiformes) and the description of a new species from the Cretaceous of Dalmatia, Croatia

ABSTRACTThe extinct clupeomorph genus Armigatus has been included in a number of phylogenetic analyses, with disagreement about its placement and relationships among the fishes of the extinct clupeomorph order Ellimmichthyiformes. There are currently four species known, all from the Late Cretaceous Tethys Sea. Here we describe a fifth species of Armigatus from Campanian deposits of Dalmatia and present a phylogenetic analysis of the genus. The new species is found to be sister group to A. oligodentatus from Morocco, and the two together form the sister group to the species from Lebanon, A. namourensis plus A. brevissimus (A. alticorpus was excluded because of lack of data). The genus Armigatus is found to be monophyletic, as are the included members of its sister group, Diplomystus, and the analysis supports the grouping of these two genera in the family Armigatidae. The relationships among the species of Armigatus indicate that these fishes arose in the eastern part of the central Tethys, then from there reached more northern (Dalmatian) and western (Morocco) areas.http://zoobank.org/urn:lsid:zoobank.org:pub:178B49D2-8D68-4C88-937E-EE93E3C424F7Citation for this article: Murray, A. M., O. Vernygora, S. Japundžić, J. Radovčić, M. V. H. Wilson, D. Bardack, and T. Grande. 2016. Relationships of the species of Armigatus (Clupeomorpha, Ellimmichthyiformes) and the description of a new species from the Cretaceous of Dalmatia, Croatia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1226851.

The status of Schowalteria clemensi, the Late Cretaceous taeniodont (Mammalia)

ABSTRACTSchowalteria clemensi Fox and Naylor, from the latest Cretaceous lower Scollard Formation, Red Deer Valley, Alberta, is the only known Mesozoic member of the extinct mammalian order Taeniodonta. Schowalteria clemensi was originally classified in the derived family Stylinodontidae, but more recent studies employing computer-assisted phylogenetic and stratocladistic analyses of taeniodont interrelationships contend that S. clemensi is the basal taeniodont, whereas Onychodectes, long considered the basal taeniodont, is instead the sister group of stylinodontids alone. These studies, however, are deeply flawed, marred by selection of problematic outgroups, incorrect scoring of numerous character states and of the stratigraphic age of S. clemensi, omission of all stylinodontid-like characters of S. clemensi, and reliance on major, implausible reversals during early taeniodont history. The more recent of these analyses also examined the relationship of taeniodonts within Eutheria, but this data set includes 54 (61%) erroneous scores for S. clemensi, the only taeniodont in the analysis. Moreover, subsequently published errata introduced new errors into the analyses. Thus, the hypothesis that S. clemensi is the earliest discovered stylinodontid remains unrefuted by these studies: the earliest history of stylinodontids and that of more basal taeniodonts is still to be discovered, among species older than S. clemensi itself.Citation for this article: Fox, R. C. 2016. The status of Schowalteria clemensi, the Late Cretaceous taeniodont (Mammalia). Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1211666.

New material of Palaeoamasia kansui (Embrithopoda, Mammalia) from the Eocene of Turkey and a phylogenetic analysis of Embrithopoda at the species level

AbstractSince the discovery of the megaherbivore Arsinoitherium zitteli Beadnell (early Oligocene of Egypt), the extinct order Embrithopoda has remained an enigmatic group, with disputed affinities among ungulates. In this study, new specimens of Palaeoamasia kansui from the early Palaeogene of Turkey are described and a synthetic dental terminology is proposed for embrithopods. Based on 130 cranial–mandibular and dental characters, the first phylogenetic analysis of embrithopods is carried out in aim to enhance the position of Palaeoamasia within embrithopods. The monophyly of Embrithopoda is confirmed, following the topology (Phenacolophus (Namatherium (Arsinoitheriinae, Palaeamasiinae))). However, phylogenetic relationships between Eurasian embrithopods (Palaeoamasiinae: Palaeoamasia, Crivadiatherium and Hypsamasia) remain unresolved. The integration of all embrithopod genera within a cladistic analysis encompassing a wider taxonomic sample (Condylarthra, Afrotheria/Paenungulata and Laurasiatheria) also supports Embrithopoda as being monophyletic, but questions the position of both Phenacolophus and Namatherium within Embrithopoda. Finally, possible faunal exchange events are proposed based on three hypothesized scenarios between Eurasia and Arabia–Africa during the early Palaeogene.

Carboniferous arachnids from the Graissessac Basin, Central Massif, France

Trigonotarbids and scorpions (Arachnida: Trigonotarbida, Scorpiones) are described from the Upper Carboniferous (Late Stephanian/Late Gzehlian) of the Graissessac Basin in the Central Massif outcropping in southern France. This is the first record of trigonotarbids and the first thorough description of scorpions from this locality. Trigonotarbids are an extinct order and the new fossils express a distinctly ornamented dorsal surface and lobed carapaces implicit of the so-called ‘eophrynid-assemblage’; probably a derived clade. Although closest to Eophrynidae, the character combination preserved precludes unequivocal assignment to any of the currently recognized families, but appears to be unique among trigonotarbids and prompts us to propose the name Aenigmatarbus rasteli gen. et sp. nov. to accommodate these novel specimens. The Graissessac scorpions are preserved in dorsal view only, but two distinct morphotypes could be recognized. These are tentatively referred to here as two typical Coal Measures genera: namely the mesoscorpion Eoscorpius sp. and the more derived orthostern Compsoscorpius sp., respectively.

Comparative anatomy and three-dimensional geometric-morphometric study of the bony labyrinth of Bibymalagasia (Mammalia, Afrotheria)

ABSTRACT—Plesiorycteropus (Malagasy aardvarks) is the sole genus belonging to an extinct mammalian order, the Bibymalagasia, that lived in Madagascar in the Quaternary. Its systematic and phylogenetic position is controversial because Plesiorycteropus morphologically resembles aardvarks (Tubulidentata), whereas a recent molecular analysis proposed that it belongs to Tenrecoidea, along with Tenrecidae (tenrecs and otter shrews) and Chrysochloridae (golden moles). This context of competing phylogenetic hypotheses is stimulating for the investigation of new characters for phylogenetic inferences. Here we used the noninvasive methods of micro-computed tomography scanning, digital reconstruction, and three-dimensional geometric-morphometric analysis of shape to investigate the morphology of the bony labyrinth (osseous inner ear) of the holotype skulls of both known species of Bibymalagasia: Plesiorycteropus madagascariensis and P. germainepetterae. Firstly, by comparisons with their extant relatives, we find that the characters of the bony labyrinth that distinguish P. madagascariensis and P. germainepetterae could only represent intraspecific variation. Secondly, we find that the bony labyrinth of Bibymalagasia is distinctive from those of other Afrotherians examined, supporting their ordinal distinctiveness. Indeed, the principal component analysis on labyrinthine shape data shows that the bony labyrinths of both Plesiorycteropus species are in fact intermediate between those of tubulidentates and other Afrotherian insectivores. Finally, we investigated the evolution of the secondary common crus (partial fusion of the lateral and posterior semicircular canals) in Afrotherians and found that this character is present in tubulidentates and potamogaline tenrecs, supporting the hypothesis that its presence is primitive for Afrotherians. In contrast, Plesiorycteropus displays the derived condition (i.e., loss of the secondary common crus).

Three-dimensional reconstruction and the phylogeny of extinct chelicerate orders.

Arachnids are an important group of arthropods. They are: diverse and abundant; a major constituent of many terrestrial ecosystems; and possess a deep and extensive fossil record. In recent years a number of exceptionally preserved arachnid fossils have been investigated using tomography and associated techniques, providing valuable insights into their morphology. Here we use X-ray microtomography to reconstruct members of two extinct arachnid orders. In the Haptopoda, we demonstrate the presence of ‘clasp-knife’ chelicerae, and our novel redescription of a member of the Phalangiotarbida highlights leg details, but fails to resolve chelicerae in the group due to their small size. As a result of these reconstructions, tomographic studies of three-dimensionally preserved fossils now exist for three of the four extinct orders, and for fossil representatives of several extant ones. Such studies constitute a valuable source of high fidelity data for constructing phylogenies. To illustrate this, here we present a cladistic analysis of the chelicerates to accompany these reconstructions. This is based on a previously published matrix, expanded to include fossil taxa and relevant characters, and allows us to: cladistically place the extinct arachnid orders; explicitly test some earlier hypotheses from the literature; and demonstrate that the addition of fossils to phylogenetic analyses can have broad implications. Phylogenies based on chelicerate morphology—in contrast to molecular studies—have achieved elements of consensus in recent years. Our work suggests that these results are not robust to the addition of novel characters or fossil taxa. Hypotheses surrounding chelicerate phylogeny remain in a state of flux.

Affinities and architecture of Devonian trunks of Prototaxites loganii

Devonian fossil logs of Prototaxites loganii have been considered kelp-like aquatic algae, rolled up carpets of liverworts, enormous saprophytic fungal fruiting bodies or giant lichens. Algae and rolled liverwort models cannot explain the proportions and branching described here of a complete fossil of Prototaxites loganii from the Middle Devonian (386 Ma) Bellvale Sandstone on Schunnemunk Mountain, eastern New York. The “Schunnemunk tree” was 8.83 m long and had six branches, each about 1 m long and 9 cm diam, on the upper 1.2 m of the main axis. The coalified outermost layer of the Schunnemunk trunk and branches have isotopic compositions (δ13CPDB) of −25.03 ± 0.13‰ and −26.17 ± 0.69‰, respectively. The outermost part of the trunk has poorly preserved invaginations above cortical nests of coccoid cells embraced by much-branched tubular cells. This histology is unlike algae, liverworts or vascular plants and most like lichen with coccoid chlorophyte phycobionts. Prototaxites has been placed within Basidiomycota but lacks clear dikaryan features. Prototaxites and its extinct order Nematophytales may belong within Mucoromycotina or Glomeromycota.

The role of charophytes (Charales) in past and present environments: An overview

Charophytes, i.e. extant and fossil members of the order Charales plus the members of the extinct orders Sycidiales and Moellerinales, are closely related to modern land plants. These algae have a complex morphology, and can tolerate salinities from freshwater up to hypersaline conditions, although they are not known to occur in fully marine habitats. Extant charophytes are found on all continents except Antarctica, in both lotic and lentic, natural and artificial habitats, ranging from ancient lakes to newly excavated gravel pits. The large size of the internode cells makes charophytes useful objects in plant cell biology. Charophytes can build up large biomasses in brackish and freshwater ecosystems, and contribute to a number of ecosystem services, including removal of nutrients from water, storage of carbon and nutrients in biomass and sediments, possible phytoremediation of organic chemicals and trace metal elements from water, as well as provision of habitat and food for a number of organisms. Charophytes are valuable indicators for lake and river ecological status assessment, and their oospores and gyrogonites are useful for paleolimnological reconstructions of ecosystem properties such as trophic status or salinity. This paper introduces charophytes, and summarizes different aspects studied in these macroalgae.

Pyrothere sistematics and a caribbean route for land-mammal dispersal during the Paleocene

The pyrotheres are an extinct order of Paleocene-Oligocene South American mammals and encompass six valid genera: Carodnia Simpson, Carolozittelia Ameghino, 1901; Proticia Patterson, 1977; Colombiterium Hoffstetter, 1970; Propyrotherium Ameghino, 1901; and Pyrotherium Ameghino, 1889. Pyrotheria is a monophyletic order of mammals united with the Dinocerata in the monophyletic Mirorder Uintatheriamorpha. Thus, the pyrotheres are not members of the Ungulata, and their inclusion in the group as members of the Mirorder Meridiungulata should be discontinued. A phylogenetic relationship between pyrotheres and dinoceratans implies dispersal of the common ancestor of North American dinoceratans and South American pyrotheres during the Paleocene , prior to the Riochican. Paleocene volcanism in the Caribbean provided an archipelago for the dispersal of the common ancestor of dinoceratans and pyrotheres.