Teeth from the late Mississippian Bangor Limestone, Monteagle Limestone, and Pride Mountain Formation (early to middle Chesterian = late Visean-early Serpukhovian) of northern Alabama, USA, are designated as Cavusodus whitei, gen. et sp. nov. The species is similar to Cypripediodens cristatus Duffin and Ward, known only from the Eyam Limestone Formation (Mississippian, late Visean) of Derbyshire, England. Cypripediodens cristatus, the only species of the genus, is distinguished by teeth having an elongate crown, an apical cusp having a nearly circular cross-section, a secondary cusp on the lingual face, and several cristae on the lingual heel. Cavusodus whitei teeth resemble those of Cypripediodens cristatus but differ in lacking the secondary cusp, in having a more labiolingually compressed apical cusp, in possessing more robust lingual cristae, and in possessing a longitudinal groove on the labial face. The genera comprising the Janassidae are reconsidered. It is proposed that only Janassa, Cholodus, and Cypripediodens be retained, in addition to the new genus.

Body size is of fundamental importance to our understanding of extinct organisms. Physiology, ecology and life history are all strongly influenced by body size and shape, which ultimately determine how a species interacts with its environment. Reconstruction of body size and form in extinct animals provides insight into the dynamics underlying community composition and faunal turnover in past ecosystems and broad macroevolutionary trends. Many extinct animals are known only from incomplete remains, necessitating the use of anatomical proxies to reconstruct body size and form. Numerous limitations affecting the appropriateness of these proxies are often overlooked, leading to controversy and downstream inaccuracies in studies for which reconstructions represent key input data. In this perspective, we discuss four prominent case studies (Dunkleosteus, Helicoprion, Megalodon and Perucetus) in which proxy taxa have been used to estimate body size and shape from fragmentary remains. We synthesise the results of these and other studies to discuss nuances affecting the validity of taxon selection when reconstructing extinct organisms, as well as mitigation measures that can ensure the selection of the most appropriate proxy. We argue that these precautionary measures are necessary to maximise the robustness of reconstructions in extinct taxa for better evolutionary and ecological inferences.

Remains of the chondrichthyan Psephodus Morris and Roberts, 1862 consist mainly of isolated tooth plates. The genus has a range from the Late Devonian (Famennian) to the Late Mississippian (Serpukhovian). The most complete specimen is a partially articulated set of teeth and tooth plates of the type species, P. magnus, from the early Serpukhovian of East Kilbride, Lanarkshire, Scotland. A row of minute nodes is present along the basal margins of the Lophodus-like and Helodus-like teeth of the East Kilbride specimen. This distinguishes these teeth from typical Lophodus-like and Helodus-like teeth. As in Helodus simplex, some specimens of Psephodus display varying degrees of fusion of teeth from the same labiolingually oriented file into tooth plates. However, unlike Helodus simplex, some specimens of Psephodus display fusion of mesiodistally separated tooth plates, each representing a fused tooth file, into a larger tooth plate. Psephodus, which crosses the Devonian-Carboniferous boundary, may be ancestral to other Mississippian holocephalians, such as Cochliodus or Chondrenchelys, in which dentitions consist of a few tooth plates with only few, or no, separate teeth. An unpublished watercolour by Agassiz's artist Dinkel depicts five tooth plates, which can be designated as syntypes of P. magnus. A lectotype for Psephodus crenulatus is designated.

ABSTRACT Restudy of Campyloprion annectans Eastman, 1902 from North America demonstrated that neither specimen included is diagnostic at the species level; thus, the species name is a nomen dubium . Since this species was designated as the type species of the genus, this requires suppression of the generic name also. Another species earlier assigned to Campyloprion , Campyloprion ivanovi Karpinsky, 1924 is used as a type for a newly established genus Karpinskiprion Lebedev et Itano gen. nov. The composition of the family Helicoprionidae Karpinsky, 1911 is reviewed, and a new family Helicampodontidae Itano et Lebedev fam. nov. is erected. A new specimen of Karpinskiprion ivanovi (Karpinsky, 1924) recently discovered in the Volgograd Region of Russia is the most complete Karpinskiprion specimen ever found. It unambiguously demonstrates the coiled nature of these tooth whorls and presents information on their developmental stages. During organogeny, cutting blades of the crown became reshaped, and basal spurs progressively elongated, forming a grater. Whorl growth occurred by addition of new crowns to the earlier mineralised base followed by later spur growth. In contrast to consistently uniform cutting blades, spurs are often malformed and bear traces of growth interruption. Both sides of the outer coil of the tooth whorl bear lifetime wear facets. The youngest (lingual) crowns are as yet unaffected by wear. The best-preserved facets show parallel radially directed scratch marks. The upper jaw dentition of Karpinskiprion is unknown, but we suggest that the faceted areas resulted from interaction with the antagonistic dental structures here. Three possible hypotheses for this interaction are suggested: (a) two opposing whorls acted as scissor blades, moving alternately from one side to another; (b) the lower tooth whorl fitted between paired parasymphyseal tooth whorls of the opposing jaw; or (c) the lower tooth whorl fitted into a dental pavement in the upper jaw.

The holotype of Psephodus minutus Wellburn, from the Millstone Grit Group (Carboniferous, Lower Pennsylvanian Series, Marsdenian Substage) of Lancashire (now Greater Manchester), England, was originally interpreted as a set of three articulated tooth plates of a chondrichthyan fish. No figure was published with the description, though a drawing was published 32 years later. Examination of the specimen shows it to be a steinkern of an indeterminate high-spired gastropod. Psephodus minutus is thus rendered as a nomen nudum.

The validity of the chondrichthyan species Petalodus ohioensis Safford 1853, has long been in doubt due to the poor quality of the published figures and the unknown whereabouts of the holotype. That situation changed with the discovery of casts of the holotype in the collections of the Yale Peabody Museum of Natural History. The quality of the casts is poor, but sufficient to establish P. ohioensis as a valid species and as a senior synonym of P. alleghaniensis Leidy 1856. Recently, casts of the holotype of much better quality were found in the collections of the Field Museum of Natural History, accompanied by documentation indicating that they were likely obtained directly from Safford by O.P. Hay in 1896. The Field Museum casts clearly show the bands of ridges at the base of the crown on the labial and lingual sides, which are not visible on the Yale Peabody Museum casts.

The symphyseal tooth whorls of the Carboniferous chondrichthyan Edestus consist of files of teeth having sharply-pointed, serrated crowns, joined at their bases. A single tooth whorl was present in each jaw. How these tooth whorls functioned is unclear, since their convex curvature allows only a few of the most lingual crowns of opposing tooth whorls to occlude. Rather than working in opposition, like scissors, the more labial teeth might have been used to cut and disable prey with a vertical motion of the anterior part of the body. Provided the scratches observed on the surface of Edestus teeth can be inferred to have been generated in the process of feeding, their orientation might be used to distinguish whether the teeth were used mainly in occlusion, to cut prey trapped between the jaws, or mainly to cut prey situated outside the oral cavity. Edestus minor teeth having unusually good surface preservation were examined for microwear. The teeth are from the Strawn Group (Desmoinesian, Middle Pennsylvanian) of San Saba County, Texas, USA. The best-preserved crown surfaces display scratches 50 to 500 micrometers long. The scratches are oriented predominantly transversely to the basal-apical axis. This observation appears to support the vertical slashing hypothesis. However, the possibility that interaction with the substrate contributed to the observed wear cannot be discounted.

Only a crude line drawing of the holotype tooth of the shark Petalodus ohioensis Safford, 1853 has ever been published, and the location of that specimen has long been unknown. The discovery of a cast of the holotype in the collections of the Yale Peabody Museum of Natural History demonstrates that P. alleghaniensis Leidy, 1856, is a junior subjective synonym of P. ohioensis, thus resolving a long-standing dispute.

Synonym(e) Bentiromid-Test; N-Benzoyl-L-tyrosyl-p-aminobenzoesäure-Test; NBT-PABA-Test; Peptid-PABA-Test Englischer Begriff NBT-PABA-test; N-benzoyl-L-tyrosylp-aminobenzoic acid test; bentiromide test Definition Indirekter Funktionstest des exkretorischen (digestiven) Pankreas, bei dem das oral applizierte synthetische Tripeptid NBT-PABA (

The term 'quantum Zeno paradox' or 'quantum Zeno effect' refers to the slowing down of the evolution of a quantum system as it is observed more and more frequently. In 1977, Misra and Sudarshan gave a theoretical demonstration of its existence. There has been disagreement regarding the definition of the effect and whether it is really a paradox, requiring new physics, or a consequence of ordinary quantum mechanics. The experiment of Itano, Heinzen, Bollinger and Wineland, published in 1990, is the one most often called a demonstration of the quantum Zeno effect. Some different interpretations are discussed.

Campyloprion Eastman, 1902 is a chondrichthyan having an arched symphyseal tooth whorl similar to that of Helicoprion Karpinsky, 1899, but less tightly coiled. The holotype of Campyloprion annectans Eastman, 1902, the type species of Campyloprion, is of unknown provenance, but is presumed to be from the Pennsylvanian of North America. Campyloprion ivanovi (Karpinsky, 1922) has been described from the Gzhelian of Russia. A partial symphyseal tooth whorl, designated as Campyloprion cf. C. ivanovi, is reported from the Missourian Tinajas Member of the Atrasado Formation of Socorro County, New Mexico, USA. Partial tooth whorls from the Virgilian Finis Shale and Jacksboro Limestone Members of the Graham Formation of northern Texas, USA, are designated as Campyloprion sp. Two partial tooth whorls from the Gzhelian of Russia that were previously referred to C. ivanovi are designated as Campyloprion cf. C. annectans. The age of Toxoprion lecontei (Dean, 1898), from Nevada, USA, is corrected from the Carboniferous to the early Permian. An alternative interpretation of the holotype of T. lecontei is presented, resulting in a reversal of its anterior-to-posterior orientation. The genera Helicoprion, Campyloprion, and Shaktauites Tchuvashov, 2001 can be distinguished by their different spiral angles.

The purpose of this application, under Article 75.6 of the Code, is to confirm the availability and to maintain the usage of the genus Petalodus Owen, 1840, which is threatened by the identity of the type specimen of its type species Petalodus hastingsii Owen, 1840. The description and figure of the specimen by Owen (1840) do not match the actual specimen, nor does it resemble the subtriangular crowns traditionally referred to the form taxon Petalodus described and illustrated by Agassiz (1838: 108–109, pl. 19, figs. 11–13) as Chomatodus (subsequently Petalodus acuminatus by Agassiz, 1843: 159, 174, nota). Additional, more complete, specimens from the same bed and locality as Owen's specimen were described and illustrated by Arthur Woodward (1889) as Petalodus acuminatus. The crowns of these teeth are labial-lingually compressed, vertically short, broad-based, subtriangular, and convex labially and concave lingually. In the subsequent 170 years, teeth identified and published as Petalodus have referred to the subtriangular teeth as described by Agassiz and Woodward, and not to the rectangular lamelliform tooth described by Owen. The Commission is therefore asked to exercise its plenary power to set aside the misleading and inadequate holotype, NHMUK PV P613, and designate as neotype specimen NHMUK PV P75414, a more complete tooth that shows all the characteristic features of Petalodus.

Edestus is a Middle Pennsylvanian chondrichthyan possessing symphyseal tooth whorls in both the upper and lower jaws. The curvature of the tooth whorls prevents most of the crowns of the opposing whorls from occluding with each other. For that reason, it has recently been hypothesized that the tooth whorls were used to slash prey with a vertical motion of the anterior part of the body, not to cut prey caught between them. A tooth of Edestus minor having a truncated, smoothly worn apex has been reported previously. Here, a partial tooth whorl of a different species, Edestus heinrichi, is described. The apices of the crowns are worn, so that the crown heights are reduced by about one third. The more labial (older) of the two preserved crowns shows more wear than the more lingual (younger) one. In contrast to the previously reported E. minor tooth, wear is observed to the serrations as well as to the apices of the crowns. The observed wear on both the E. minor tooth and on the E. heinrichi tooth whorl supports the recent hypothesis on the function of the tooth whorls. In both cases, the apices might have been abraded by attempted predation on or scavenging of large fish having skin covered with denticles or scales.

BACKGROUND:Paleozoic holocephalian tooth plates are rarely found articulated in their original positions. When they are found isolated, it is difficult to associate the small, anterior tooth plates with the larger, more posterior ones. Tooth plates are presumed to have evolved from fusion of tooth files. However, there is little fossil evidence for this hypothesis.RESULTS:We report a tooth plate having nearly perfect bilateral symmetry from the Mississippian (Chesterian Stage) Bangor Limestone of Franklin County, Alabama, USA. The high degree of symmetry suggests that it may have occupied a symphyseal or parasymphyseal position. The tooth plate resembles Deltodopsis? bialveatus St. John and Worthen, 1883, but differs in having a sharp ridge with multiple cusps arranged along the occlusal surface of the presumed labiolingual axis, rather than a relatively smooth occlusal surface. The multicusped shape is suggestive of a fused tooth file. The middle to latest Chesterian (Serpukhovian) age is determined by conodonts found in the same bed.CONCLUSION:The new tooth plate is interpreted as an anterior tooth plate of a chondrichthyan fish. It is referred to Arcuodus multicuspidatus Itano and Lambert, gen. et sp. nov. Deltodopsis? bialveatus is also referred to Arcuodus.

We evaluate the electric quadrupole moments of the ${^1}\!S_0$ and ${^3}\!P_0$ clock states of $^{27}$Al$^+$ and $^{115}$In$^+$. To capture all dominant contributions, our analysis extends through third order of perturbation theory and includes hyperfine coupling of the electrons to both the magnetic dipole and electric quadrupole moments of the nucleus. For $^{27}$Al$^+$, a fortuitous cancellation leads to a suppressed frequency shift. This should allow for continued improvement of the clock without special techniques to control or cancel the shift, such as the averaging schemes that are critical to other optical ion clocks.

Edestus is a Carboniferous chondrichthyan genus known mainly from its triangular, serrated teeth. A maximum of around ten teeth are joined at their bases to form tooth whorls. Edestus minor Newberry, 1866, was described on the basis of a single, isolated tooth. A tooth whorl containing seven teeth, described and figured by Hitchcock in 1856, but not named by him, was later referred to E. minor by Newberry, who came to regard it as the holotype. However, the isolated tooth remains the holotype, since it is the sole specimen upon which the original description was based. The distinction is not trivial, because the crown of the holotype of E. minor differs from those present in Hitchcock's specimen. Edestus mirus Hay, 1912, was designated as a new species, based on differences from the Hitchcock specimen, although the crowns are not distinguishable from those of the holotype of E. minor. Thus, E. mirus is almost certainly a junior synonym of E. minor, while the Hitchcock specimen may require a new name. If so, it should probably be referred to Edestus minusculus Hay, 1910. Recently, the holotype of E. minor was located at the American Museum of Natural History, where it had not been recognized as a type specimen. Published documents as well as nineteenth- century museum labels provide some insight into this tangled nomenclatural history.

A partial symphyseal tooth whorl of Campyloprion sp., comprising five teeth, is reported from the Tinajas Member of the Atrasado Formation of Socorro County, southern New Mexico.The age is constrained by both fusulinid and conodont biostratigraphy to the Missourian Stage (Upper Pennsylvanian).The holotype of Campyloprion annectans, the type species of Campyloprion, is of unknown provenance, although it has been presumed to be from the Upper Pennsylvanian of Midwestern North America.Tooth whorls of Campyloprion are more loosely coiled than those of the better-known edestoid Helicoprion; the tooth whorls of both genera are shaped like logarithmic spirals.The parameter that characterizes a logarithmic spiral, the angle between a tangent to the spiral and a radius from the center, is about 60° for Campyloprion versus about 82° for Helicoprion.The New Mexico specimen is not complete enough for this angle to be determined.Determination of the genus is therefore based on the morphology of the individual teeth, particularly the serrations, which compare closely to those of the holotype of Campyloprion ivanovi from the Upper Pennsylvanian of Russia.This is the first record of Campyloprion from New Mexico, and the most complete edestoid fossil known from New Mexico.

The observation of intermittent fluorescence of a single atomic ion, a phenomenon better known as ‘macroscopic quantum jumps,’ was an important early scientific application of the three-dimensional rf quadrupole (Paul) trap. The prediction of the phenomenon by Cook and Kimble grew out of a proposal by Dehmelt for a sensitive optical double-resonance technique, called ‘electron shelving.’ The existence of the quantum jumps was viewed with skepticism by some in the quantum optics community, perhaps due to the failure of some conventional calculations, for example the solutions to the optical Bloch equations, to predict them. Quantum jumps were observed nearly simultaneously by three different experimental groups, all with single, isolated ions in Paul traps. Some slightly earlier observations of excessive fluctuations in the laser-induced fluorescence of a single Hg+ ion by a group at the National Institute of Standards and Technology, viewed in retrospect, were due to quantum jumps. Similarly, sudden changes in the resonance fluorescence of trapped Ba+ ions observed by a group at the University of Hamburg were due to quantum jumps, although this was not understood at first. This shows how discoveries can be missed if unanticipated observations are ignored rather than investigated. A fourth experiment, performed not with a single, trapped ion, but with neutral atoms transiently observed in an atomic beam, and published at about the same time as the other experiments, has been almost totally neglected.