Exceptional continental record of biotic recovery after the Cretaceous-Paleogene mass extinction.

We report a time-calibrated stratigraphic section in Colorado that contains unusually complete fossils of mammals, reptiles, and plants and elucidates the drivers and tempo of biotic recovery during the poorly known first million years after the Cretaceous-Paleogene mass extinction (KPgE). Within ~100 thousand years (ka) post-KPgE, mammalian taxonomic richness doubled, and maximum mammalian body mass increased to near pre-KPgE levels. A threefold increase in maximum mammalian body mass and dietary niche specialization occurred at ~300 ka post-KPgE, concomitant with increased megafloral standing species richness. The appearance of additional large mammals occurred by ~700 ka post-KPgE, coincident with the first appearance of Leguminosae (the bean family). These concurrent plant and mammal originations and body-mass shifts coincide with warming intervals, suggesting that climate influenced post-KPgE biotic recovery.

A pug-nosed crocodyliform from the Late Cretaceous of Madagascar.

Although the image of crocodyliforms as 'unchanged living fossils' is naive, several morphological features of the group are thought to have varied only within narrow limits during the course of evolution. These include an elongate snout with an array of conical teeth, a dorsoventrally flattened skull and a posteriorly positioned jaw articulation, which provides a powerful bite force. Here we report an exquisitely preserved specimen of a new taxon from the Late Cretaceous of Madagascar that deviates profoundly from this Bauplan, possessing an extremely blunt snout, a tall, rounded skull, an anteriorly shifted jaw joint and clove-shaped, multicusped teeth reminiscent of those of some ornithischian dinosaurs. This last feature implies that the diet of the new taxon may have been predominantly if not exclusively herbivorous. A close relationship with notosuchid crocodyliforms, particularly Uruguaysuchus (Late Cretaceous, Uruguay) is suggested by several shared derived features; this supports a biogeographical hypothesis that Madagascar and South America were linked during the Late Cretaceous.

Superfamily Gondwanatherioidea: a previously unrecognized radiation of multituberculate mammals in South America.

Multituberculates were the longest-lived order of the Class Mammalia and, during the Mesozoic and early Cenozoic, were among the most diverse and abundant representatives of the class. However, until the recent discovery of two Cretaceous teeth, one from South America and one from Africa, they were known only from northern continents. Additional material of the South American form Ferugliotherium has confirmed its multituberculate affinities and indicates that it may be a derived member of the Suborder Plagiaulacoidea. New specimens provide evidence that two other South American forms, Gondwanatherium and Sudamerica, are also multituberculates and that they are closely related to Ferugliotherium. Gondwanatherium and Sudamerica, each possessing highly specialized hypsodont molars, were previously thought to be the earliest known representatives of the Edentata, to be involved in the origin of edentates, or to represent a previously unknown higher taxon of mammals. However, there are detailed similarities in gross dental morphology, enamel microstructure, and inferred direction of jaw movement among Ferugliotherium, Gondwanatherium, and Sudamerica. All three genera are here regarded as representatives of a highly derived, endemic radiation of South American multituberculates and are allocated to the superfamily Gondwanatherioidea. Multituberculates were therefore more common elements of Late Cretaceous and early Paleocene mammalian faunas of South America than previously recognized.

Post-Jurassic mammal-like reptile from the Palaeocene.

Mammal-like reptiles of the order Therapsida document the emergence of mammals from more primitive synapsids and are of unique zoological and palaeontological interest on that account. Therapsids, first appearing in the Early Permian, were thought to become extinct in the Middle Jurassic, soon after the Late Triassic origin of mammals. Here, however, we report the discovery of a therapsid from the late Palaeocene, 100 million years younger than the youngest previous occurrence of the order. This discovery nearly doubles the stratigraphic range of therapsids and furnishes their first record from the Cenozoic. The documenting fossils, an incomplete dentary containing three teeth, and four isolated teeth from other, conspecific individuals (Fig. 1), are from the Paskapoo Formation, at Cochrane, Alberta, Canada, from beds yielding a diverse mammalian fauna of early Tiffanian age. These specimens are catalogued in the collections of the University of Alberta Laboratory for Vertebrate Paleontology (UALVP) and provide the basis for a new taxon, as named and described below: (see text)

Analysis of individual, intraspecific and interspecific variability in quantitative parameters of caprine tooth enamel structure.

Qualitative and quantitative features of mammalian tooth enamel structure are increasingly being used in taxonomic and phylogenetic analyses, although the variability shown by these traits has not received adequate consideration. This study evaluates the variability displayed by nine quantitative parameters in deep, intermediate, and superficial molar enamel in the closely related bovids Ovis aries and Capra hircus. These parameters are assessed in terms of the absolute and/or relative variability evinced at a given depth within a single individual, among conspecific individuals, and between species samples. The degrees of relative variability expressed at a given depth are comparable among conspecific individuals and between taxonomic samples. Nevertheless, in many instances, there are significant differences in absolute variability amongst individuals. Also, in four parameters for which individual specimen averages could be calculated, the equality of these means among conspecifics can be rejected. Variability is not equivalent at different enamel depths. The null hypothesis of equality of individual, conspecific variances can be rejected most commonly for parameters measured in deep and superficial enamel, and coefficients of variation also tend to be higher for deep and superficial enamel than for enamel of intermediate depth. The greater variability displayed by deep and especially superficial enamel may be related to the initial onset and the terminal phase of ameloblastic secretory activity. Taxonomic and phylogenetic analyses that utilize quantitative data on enamel structure are valid only if comparisons have been made at equivalent enamel depths.

The enamel ultrastructure of multituberculate mammals: a review.

The enamel ultrastructure of multituberculate mammals has been sampled extensively and studied intensively and is better known than for any other group of early mammals. The enamel of the earliest multituberculates, those of the Late Triassic-Early Jurassic suborder Haramiyoidea and the Late Jurassic-early Early Cretaceous suborder Plagiaulacoidea, is "preprismatic." With only two exceptions, all Late Cretaceous and early Tertiary genera of multituberculates examined have prismatic enamel. Prisms are either small with circular (complete) boundaries or large with arc-shaped (incomplete) boundaries. There is a remarkably consistent relationship between enamel ultrastructural type and subordinal taxa in that small, circular prisms are usually found within the suborder Ptilodontoidea and large, arc-shaped prisms are usually found in the suborder Taeniolabidoidea and in six Late Cretaceous-Early Tertiary genera of indeterminate subordinal status. Research currently in progress suggests that both small, circular prisms and large, arc-shaped prisms are homologous in all multituberculates in which they occur, with one exception. Neoliotomus, a taeniolabidoid, appears to have evolved small, circular prisms independently. In addition, it appears that large, arc-shaped prisms represent the primitive condition in multituberculates with prismatic enamel, not small, circular prisms as has been proposed previously.

Pathophysiology and immunology of the Jarisch-Herxheimer-like reaction in louse-borne relapsing fever: comparison of tetracycline and slow-release penicillin.

Twelve men with louse-borne relapsing fever were treated with single doses of procaine penicillin plus aluminum monostearate (PAM) intramuscularly or of tetracycline intravenously. All patients experienced a definite Jarisch-Herxheimer-like reaction. Fever and spirochetemia were significantly prolonged and peak temperature was lower and occurred later in the PAM-treated group. Peak pulmonary ventilation, metabolic rate, and arterial PO2 were significantly higher in the tetracycline-treated group. Circulatory changes were similar in the two groups but were prolonged in the PAM-treated patients. Thus, tetracycline is recommended for treatment because it is more rapidly effective in eliminating Borrelia spirochetes and produces a reaction no more stressful physiologically than the one after PAM. There was no evidence of complement activation, and there was no change in immunoglobulin levels throughout the reaction. Immune complexes were detected in serum of five patients before treatment, but in fewer patients at the peak of the reaction and subsequently.

Adaptations for climbing in north american multituberculates (mammalia).

A recently discovered skeleton of Ptilodus exhibits several specializations for climbing. A survey of postcranial bones of Cretaceous and early Cenozoic multituberculates from North America reveals similar locomotor specializations. Multituberculates possessed distinctive tarsal adaptations for a range of pedal mobility characteristic of arboreal mammals that descend trees headfirst. The divergent hallux could move independently of the other digits. The long robust tail of Ptilodus possessed musculoskeletal features that, among living mammals, are associated with prehensility.

Pelvic inflammatory disease and puerperal sepsis in Ethiopia. II. Treatment.

Where bacteriologic support is lacking, a combination of penicillin and streptomycin (P/S) is used empirically to treat serious gynecologic infections in Ethiopia. We compared the efficacy of P/S to a combination of penicillin and chloramphenicol (P/C) in hospitalized women who had bacteriologically confirmed pelvic inflammatory disease or puerperal sepsis (PPS). Treatment of PPS with P/C was significantly more effective in limiting the duration of fever than was treatment with P/S. Twenty-eight of 40 PPS patients had endometritis with retained products of conception that required evacuation of the uterus. The duration of fever in patients with PID who were treated with the P/C regimen was no different than that in those treated with P/S. Twenty of the 24 PID patients required surgery for drainage of abscesses, in addition to antibiotics.

PIP: Where bacteriologic support is lacking, a combination of (P/S) penicillin and streptomycin is used empirically to treat serious gynecolgoic infections in Ethiopia. We compared the efficacy of P/S to a combination of (P/C) penicillin and chloramphenicol in hospitalized women who had bacteriologically confirmed (PID) pelvic inflammatory disease or (PPS) puerperal sepsis. Treatment of PPS with P/C was significantly more effective in limiting the duration of fever than was treatment with P/S. 20 of the 40 PPS patients had endometritis with retained products of conception which required evacuation of the uterus. The duration of fever in patients with PID who were treated with the P/C regimen was no different than that in those treated with P/S. 20 of the 24 PID patients required surgery for drainage of abscesses, in addition to antibiotics.

Pelvic inflammatory disease and puerperal sepsis in Ethiopia. I. Etiology.

Among 100 outpatient women with symptoms and signs of pelvic inflammatory disease and 200 asymptomatic, postpartum women, the prevalence rates of Neisseria gonorrhoeae were 19% and 9%, respectively. Of 46 women hospitalized for PID, 33% were culture-negative, 22% grew Enterobacteriaceae, 20% grew streptococci, 15% grew gonococci, and 15% grew anaerobes from blood, pus, or abscesses. One third of 67 women hospitalized for puerperal sepsis (PPS) were culture-negative; the bacteria isolated most frequently from the uterus, blood, urine, and pus were Enterobacteriaceae (36%), gonococci (28%), streptococci (25%), and anaerobes (4%). The low frequency of isolation of anaerobes in women with PID and PPS was due largely to limitations placed on the collection and processing of specimens for anaerobic bacteriology.

Studies on the pathogenesis of fever. XIV. Further observations on the chemistry of leukocytic pyrogen.

Leukocytic pyrogen previously reported to contain an essential protein moiety, appears to be a lipid-protein complex having a molecular weight in the range of 10,000 to 20,000. Evidence that it contains essential lipid includes its inactivation by Cu(++), its lability in alkaline solutions (pH 8.5 and above), and its loss of pyrogenicity when extracted with acid-isooctane. Its solubility in 66% methanol, and the enhancing action of ethanol in freeing it from sonicated cells, suggest the presence of exposed lipid groups at its surface. Once the complex is separated from other proteins, its biological activity is readily destroyed. Although the lipid component is presumed to contain unesterified fatty acid(s), its precise composition is unknown. The finding of lipid in the active complex is in keeping with the hypothesis that the pyrogen is derived from leukocytic membranes.