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A new planktonic foraminifera species (Igorina isabellae n. sp.) from the late Paleocene of the Pacific Ocean
No full textPlanktonic foraminiferal bioevents and evolutionary trends across the late Paleocene Globanomalina pseudomenardii Zone in the tropical-subtropical Pacific record (ODP Leg 143 and 198)
No full textOn the phylogeny of Paleogene planktonic foraminifera: wall texture structure and a new genus name for the broedermanni lineage
No full textThe broedermanni lineage has been traditionally placed in the genus Igorina (see Berggren and others, 2006) being characterized by possessing a biconvex globorotaliid morphology, subglobular to subquadrate chambers, and by having a nonspinose wall texture with thin muricae on the test surface. Our analysis of specimens from the Pacific Ocean (ODP Leg 198, Shatsky Rise and ODP Leg 143, Alllison Guyot) suggest that the broedermanni group is phylogenetically related to Acarinina as the calcite structures of the wall are similar to the muricae rather than to the short pustules of the Paleocene igorinids (i. e., I. pusilla, I. albeari). In particular, the oldest species lodoensis shows a typical coarse muricate test similar to Acarinina while in its descendants, broedermanni and anapetes, the muricae are finer on the spiral side, and heavier muricae are developed only around the umbilicus. Moreover, in the broedermanni group the shell is not encrusted as in Igorina because the pustules remained isolated and increased in size to become thick muricae. The analysis of the pore structure in cross section seems to confirm the similarities and affinities between the wall texture of the broedermanni group and Acarinina. Both show an hourglass shape of the pores that become narrow in the outer calcite layer whereas in Igorina species the pores are tight in the inner calcite layer. In addition, the results from parsimony analysis (Soldan and other, 2011) confirm that the broedermanni group evolved in the late Paleocene/early Eocene from the group of round acarininids (A. mckannai and A. soldadoensis).
The new genus Pearsonites (named in honor of Professor Paul N. Pearson) with Pearsonites broedermanni as type species, is here proposed to accommodate the early-middle Eocene globorotaliid taxa of the broedermanni lineage with a wall texture bearing muricae. Three species previously considered morphologically and evolutionary related to the Paleocene genus Igorina are here included in Pearsonites nov. gen., P. lodoensis, P. broedermanni, and P. anapetes. Species assigned to Pearsonites nov. gen. are relatively common in the stratigraphic interval from the upper Paleocene (Zone P5) to the middle Eocene (Zone E9).
References
Berggren W.A., Pearson P.N., Huber B.T., Wade B.S., 2006. Chapter 19: Taxonomy, biostratigraphy and phylogenetic affinities of Eocene Acarinina, in Pearson P. N., Olsson R.K, Huber B.T., Hemleben C., Berggren W.A (eds), Atlas of Eocene Planktonic Foraminifera: Cushman Foundation Special Pubblication, v. 41, p. 257-326.
Soldan D.M., Petrizzo M.R., Premoli Silva I., Cau A., 2011. Phylogenetic relationships and evolutionary history of the Paleogene genus Igorina through parsimony analysis: Journal of Foraminiferal Research, v. 41, p. 260-284
REVISION OF PALEOCENE-EOCENE PLANKTIC FORAMINIFERAL BIOSTRATIGRAPHY AND EVOLUTIONARY HISTORY OF THE GENUS IGORINA THROUGH PARSIMONY ANALYSIS.
No full textThe evolution of planktonic foraminifera in the Paleocene-Eocene time interval is characterized by a high rate of diversification after the major extinction event observed at the Cretaceous/Paleogene boundary. The accelerated speciation rate resulted in the appearance of several new genera (i.e., Praemurica, Igorina, Morozovella, Acarinina among others) each of them identified on the basis of distinctive wall texture of the shell. Phylogenetic relationships within many genera are still poor understood including the origin and phylogeny of the genus Igorina. This group, characterized by a thick, nonspinose and incrusted wall, appears in Subzone P3a (early late Paleocene, Selandian) and disappears in Zone E9 (middle Eocene, Lutetian). To date, eight species have been assigned to the genus Igorina (I. pusilla, I. trichotrocha, I. tadjikistanensis, I. albeari, I. laevigata, I. lodoensis, I. broedermanni and I. anapetes) based on both wall texture and morphologic similarities. However, the taxonomic identification at species level is affected by several problems, mainly related to poor descriptions and illustrations of the type-material of several species. Consequently, for many years the morphological features proper of each species have been frequently misinterpreted.
This study is aimed to reconstruct the phylogeny and evolution of the igorinid species throught cladistic analysis by applying the method of parsimony. To perform the study, two hundred
samples have been analysed from Ocean Drilling Program (ODP) Leg 198 Hole 1209B (Shatsky Rise, Central Pacific Ocean), Leg 143 Hole 865B (Allison Guyot, Central Pacific Ocean), Leg 15 Sites 151 and 152 (Caribbean Sea) and Leg 113 Hole 690B. The biostratigraphic analysis of sub-tropical localites revealed some problems in applying the previous biostratigraphic scheme (Berggren and Pearson, 2005) mainly because some marker species 1) have been misinterpreted and/or misidentified several times in previous studies, 2) show a delayed appearance with respect to what reported from other localities, and 3) are very rare or absent in the studied samples. Species identification was mainly performed through comparison with the original descriptions and illustrations and partially follows Subbotina (1953), Blow (1979), Olsson and others (1999), Pearson and others (2006). Phylogenetic relationships of the species assigned to Igorina are determined through stratocladistic analysis by using a data matrix of 23 taxa (including key species of Acarinina), 31 morphological characters (unordered), and a stratigraphic character (ordered) mapping the first occurrence of the taxa under investigation. The morphological characters included in this analysis are based on morphometric measurements such as the angle of chambers, maximum diameter of the shell, maximum diameter of the inner whorls, angle of peripheral margin among others. The same characters were also measured on the SEM illustrations of the type species of each holotype and, hence, included in the data matrix.
Some morphotypes of uncertain taxonomic identification but showing consistent morphological and wall texture features have been coded and analysed separately as morphotypes A, B, C, D, E and F to determine their ancestor-descendant relationships and evaluate their validity as discrete species. The software PAUP* (Swofford 2002) has been used to process the data and to obtain a numerical matrix with codified the selected characters, then the matrix has been processed using the heuristic search option to discover the most parsimonious trees.
Results suggest that Igorina pusilla is the first representatives of the Igorina lineage and is subsequently followed by I. laevigata. I. albeari, and I. tadjikistanensis in agreement with their stratigraphic distribution. Morphotypes (C, E, F) have been included in Igorina paraspiralis (Soldan and others, in press) while Igorina morphotype A represents a single species (Igorina praecarinata Soldan and others, in press). Morphotypes B and E fall in the variability of well-know species. Moreover, the analysis provides evidence that I. trichotrocha, I. lodoensis, I. broedermanni and I. anapetes are more closely related to genus Acarinina than Igorina and clearly belong to a different lineage. A preliminary analysis of the wall texture architectures the broedermanni group has been performed to assess their ancestor-descendant relationships and to evaluate the possibility to place them in a discrete new genus
On the phylogeny of the Paleocene-Eocene genus Igorina (planktonic foraminifera): preliminary results from a parsimony analysis
No full textPhylogenetic relationships and evolutionary history of the Early Paleogene genus Igorina (planktonic foraminifera) through parsimony analysis
No full textPearsonites, a new Paleogene planktonic foraminiferal genus for the Broedermanni lineage
No full textThe new genus Pearsonites with P. broedermanni as type species is herein formalized to accommodate the early to middle Eocene globorotaliform taxa of the broedermanni lineage with a wall texture bearing muricae. Our analysis of specimens from the Pacific Ocean reveals a substantial similarity in wall structure with the genus Acarinina. In particular, the development and organization of the muricae, the hourglass shape of the pores, and the morphological features suggest that Pearsonites nov. gen. evolved from Acarinina in the late Paleocene. Herein we group three species previously considered morphologically and evolutionarily related to the Paleocene genus Igorina Davidzon, 1976, within Pearsonites nov. gen.: P. broedermanni (Cushman & Bermudez, 1949), P. lodoensis (Mallory, 1959), and P. anapetes (Blow, 1979). Species assigned to Pearsonites nov. gen. are relatively common in the stratigraphic interval from the late Paleocene (Zone P5) to the middle Eocene (Zone E9)
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
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
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