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A new Perleididae from the Spathian (Olenekian, Early Triassic) of Chaohu, Anhui Province, China
No full textA new actinopterygian genus and species, Chaohuperleidus primus gen. n. sp. n., is described from the Upper Member of the Nanlinghu Formation (Spathian, Olenekian, Early Triassic) at Majiashan (Majia Hill), Chaohu City, Anhui Province, Southeast China. The new taxon is assigned to the order Perleidiformes on the base of a combination of features, such as large wedge-like preoperculum with expanded infraorbital process with the sensory canal running almost vertical along the posterior margin of the preoperculum itself and flank scales are somewhat higher than longer in the trunk region and presence of epaxial rays in the caudal fin. Among Perleidiformes, the new taxon belongs to the Perleididae, being very similar to Perleidus in the general body shape, pattern of the skull bones, the dentition made of peg-like marginal teeth,and number of epaxial rays. The new genus is characterized by the presence of a very large antero-dorsal process on the suboperculum, a high number (about 55) of transversal scale rows and dorsal and anal fin quite posterior. Chaohuperleidus gen. n. being Spathian in age, represents the oldest record of the order Perleidiformes
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A new species of Qianichthyosaurus (Reptilia: Ichthyosauria) from Xingyi Fauna (Ladinian, Middle Triassic) of Guizhou
No full textA new species of Qianichthyosaurus Li, 1999 from the Zhuganpo Member of the Falang Formation (Ladinian, Middle Triassic), Wusha Town, Xingyi City of Guizhou is described here, namely Qianichthyosaurus xingyiensis sp. nov. The recognition of the new species revises the diagnosis of the genus: tooth size relative to the
skull width slightly below 0.1; ulna peripheral “shaft” notched or largely reduced; hindlimb nearly equal or longer than forelimb; tibia peripheral “shaft” notched or largely reduced. Qianichthyosaurus xingyiensis sp. nov. differs from the type species in having relatively longer snout (snout length/skull length over 60%); humerus radial facet being prominently larger than ulnar facet; unenclosed obturator foramen on pubis; fibula posterior process on the posterior margin and the ischium sub-triangular lacking shaft. The new species is stratigraphically older than Q.zhoui, the specimens of which were exclusively known from the Wayao Member of the Falang Formation (Carnian, Late Triassic). Along with askeptosaurid thalattosaur Anshunsaurus and shastasaurid ichthyosaur Guizhouich-
thyosaurus, the occurrence of Q. xingyiensis sp. nov. in Xingyi Fauna suggests a closer relationship between Xingyi Fauna (late Ladinian, Middle Triassic) and Guanling Biota (Carnian, Late Triassic)
Ammonoid age control of the Early Triassic marine reptiles from Chaohu (South China)
No full textHere we described a series of ammonoid specimens from the Early Triassic of Chaohu, South China and recognized the occurrence of Procolumbites for the first time in this area. The Procolumbites layer is about one meter above the first appearance of Chaohusaurus, indicating that the oldest Chaohusaurus is within the Procolumbites Zone of middle Spathian age. This new age constrain is significantly older than the previously suggested Subcolumbites Zone assignment (early late Spathian). To date, Chaohusaurus is the oldest known ichthyopterygian
Terrestrial origin of viviparity in Mesozoic marine reptiles indicated by early triassic embryonic fossils
Get PDFViviparity in Mesozoic marine reptiles has traditionally been considered an aquatic adaptation. We report a new fossil specimen that strongly contradicts this traditional interpretation. The new specimen contains the oldest fossil embryos of Mesozoic marine reptile that are about 10 million years older than previous such records. The fossil belongs to Chaohusaurus (Reptilia, Ichthyopterygia), which is the oldest of Mesozoic marine reptiles (ca. 248 million years ago, Early Triassic). This exceptional specimen captures an articulated embryo in birth position, with its skull just emerged from the maternal pelvis. Its headfirst birth posture, which is unlikely to be a breech condition, strongly indicates a terrestrial origin of viviparity, in contrast to the traditional view. The tail-first birth posture in derived ichthyopterygians, convergent with the conditions in whales and sea cows, therefore is a secondary feature. The unequivocally marine origin of viviparity is so far not known among amniotes, a subset of vertebrate animals comprising mammals and reptiles, including birds. Therefore, obligate marine amniotes appear to have evolved almost exclusively from viviparous land ancestors. Viviparous land reptiles most likely appeared much earlier than currently thought, at least as early as the recovery phase from the end-Permian mass extinction
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
A new ‘flying’ fish from the Late Ladinian (Middle Triassic) of Wusha (Guizhou Province, southern China)=Un nuovo pesce "volante" dal Ladinico superiore (Triassico medio) di Wusha (provincia del Guizhou, Cina meridionale)
No full textLa distribuzione dei pesci “volanti” fossili, con 4 specie appartenenti al genere Thoracopterus, era finora ristretta all’area alpina (corrispondente alla Tetide occidentale durante il Triassico) e all’intervallo di tempo compreso tra il Carnico inferiore di Raibl-Cave del Predil (Udine, Friuli) e il Norico medio-superiore del Calcare di Zorzino (Lombardia). Nuovi ritrovamenti sono venuti alla luce durante lo scavo sistematico di un’ampia superficie del livello fossilifero del Ladinico superiore nel Membro Zhuganpo della Formazione Falang che ha fornito la famosa “Xingyi Fauna” dominata dal pachipleurosauro Keichousaurus. Essi permettono di ampliare la distribuzione, sia areale che stratigrafica, di Thoracopterus, anticipando la comparsa di questo particolare pesce “subolosteo” alla fine del Triassico Medio, cioè nel Ladinico superiore. Lo scavo si sta svolgendo nei pressi del villaggio di Nimaigu (Distretto di Wusha, Xingyi City, provincia del Guizhou, Cina Meridionale) e
interessa globalmente una superficie di strato di quasi 1000 mq; tuttavia lo scavo di dettaglio per la ricerca soprattutto dei piccoli pesci si svolge su una superficie variabile tra i 10 e i 20 mq. La nuova specie di Thoracopterus che viene qui descritta è simile a T. telleri, conosciuto nel Carnico Inferiore di Lunz (Austria), sia nelle dimensioni che nella quasi totale assenza di scaglie sul
corpo; questo carattere peraltro è comune anche alle due specie del Norico, T. martinisi e T. magnificus, nelle quali le scaglie sono però totalmente assenti. La nuova specie cinese si differenzia da T. telleri per la presenza di un campo relativamente ampio di piccole scaglie sub-quadrate subito dietro il cranio e un altro a supporto del lobo ventrale della caudale. Le scaglie della
regione dorso-toracica hanno la superficie ornamentata da sottili e brevi strie di ganoina. Come in molti Peltopleuriformes la nuova specie di Thoracopterus presenta dimorfismo sessuale sulla base di una differenziazione della pinna anale. I supposti maschi hanno ossa craniche e pinne pettorali più robuste, mentre le femmine mostrano una ornamentazione delle scaglie
dorso-toraciche più sviluppata e la pinna anale modificata con parte posteriore formata da raggi molto sottili e dotati di una serie di uncini terminali.‘Flying’ (gliding) fishes have been known since the XIX century from the Late Triassic of northern Italy and Austria. So far, four species had been ascribed to the genus Thoracopterus. Now a new species is erected on well preserved specimens from new extensive and detailed excavation started in the summer 2011 near the village of Nimaigu (Wusha District, Xingyi City, Guizhou Province, southern China). The investigation concerns a rich vertebrate level in the Late Ladinian Zhuganpo Member of the Falang Formation. This vertebrate assemblage is well known mainly because it contains abundant pachipleurosaur Keichousaurus, as well as nothosaurs, ichthyosaurs and a few fish genera. During the bed by bed excavation several specimens of a new ‘flying’ fish have been collected; mainly on the basis of a peculiar partial scale covering, limited to the antero-dorsal and ventral caudal regions, we erect a new species. This new species is closer to the Carnian Thoracopterus telleri than to any of the other three species and it is the oldest known ‘flying’ fish
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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