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Figure 1 in Snakes on an African plain: the radiation of Crotaphopeltis and Philothamnus into open habitat (Serpentes: Colubridae)
No full textFigure 1 Habitat classification for genetic samples of Crotaphopeltis and Philothamnus species. Sampled localities were projected onto the biome map of Olson et al. (2001). Closed habitat (forest classes) is indicated by darker grey shades. Open habitat (including savanna) is shaded white to light grey. Full-size DOI: 10.7717/peerj.11728/fig-1Published as part of Engelbrecht, Hanlie M., Branch, William R. & Tolley, Krystal A., 2021, Snakes on an African plain: the radiation of Crotaphopeltis and Philothamnus into open habitat (Serpentes: Colubridae), pp. 1-18 in PeerJ (e11728) 9 on page 7, DOI: 10.7717/peerj.11728, http://zenodo.org/record/575307
FIGURE 4 in A new species of tree snake (Dipsadoboa, Serpentes: Colubridae) from 'sky island' forests in northern Mozambique, with notes on other members of the Dipsadoboa werneri group
No full textFIGURE 4. Right everted hemipenis of Dipsadoboa montisilva sp. nov., holotype (PEM R21122) viewed from the asulcal surface. Note the zonal distribution of ornamentation with basal spines and calyculate cap, and the two largest basal spines (bottom right of image) that border the asucal nude zone.Published as part of Branch, William R., Bayliss, Julian, Bittencourt-Silva, Gabriela B., Conradie, Werner, Engelbrecht, Hanlie M., Loader, Simon P., Menegon, Michele, Nanvonamuquitxo, Cristóvão & Tolley, Krystal A., 2019, A new species of tree snake (Dipsadoboa, Serpentes: Colubridae) from 'sky island' forests in northern Mozambique, with notes on other members of the Dipsadoboa werneri group, pp. 541-563 in Zootaxa 4646 (3) on page 554, DOI: 10.11646/zootaxa.4646.3.6, http://zenodo.org/record/335110
FIGURE 5 in A new species of tree snake (Dipsadoboa, Serpentes: Colubridae) from 'sky island' forests in northern Mozambique, with notes on other members of the Dipsadoboa werneri group
No full textFIGURE 5. Type locality of Dipsadoboa montisilva sp. nov., Mt Mabu Forest Base Camp, Zambezia Province, Mozambique. A: general view of the evergreen mid-altitude wet forest close to the base camp. B: low trees and riverine bushes beside stream at base camp.Published as part of Branch, William R., Bayliss, Julian, Bittencourt-Silva, Gabriela B., Conradie, Werner, Engelbrecht, Hanlie M., Loader, Simon P., Menegon, Michele, Nanvonamuquitxo, Cristóvão & Tolley, Krystal A., 2019, A new species of tree snake (Dipsadoboa, Serpentes: Colubridae) from 'sky island' forests in northern Mozambique, with notes on other members of the Dipsadoboa werneri group, pp. 541-563 in Zootaxa 4646 (3) on page 555, DOI: 10.11646/zootaxa.4646.3.6, http://zenodo.org/record/335110
The radiation and biogeography of snakes across south-eastern Africa with respect to the evolution of the savanna biome
Get PDFThesis (PhD)--Stellenbosch University, 2017.ENGLISH ABSTRACT: The heterogeneous landscape of the African continent was preceded by a pan-African forest that has
been transformed by concomitant contractions and expansions of this biome since the Oligocene
epoch, to primarily savanna at present. As such, faunal groups that emerged during the
Paleogene/Neogene period and have species distributed in both forest and savanna habitat should
show a genetic signature of the possible evolutionary impact of these biome developments.
Crotaphopeltis and Philothamnus were ideal candidate taxa to investigate the evolutionary impact of
these biome developments on widespread African colubrid snakes. Species in these two genera occur
throughout sub-Saharan Africa and are associated with either closed (forest), open (e.g. savanna),
as well as both habitat types. The main research aim was to investigate synchronised timing and
patterns of radiation for Crotaphopeltis and Philothamnus with respect to these African biome
developments. Knowledge of the evolutionary relationships for the two genera was needed to
construct their biogeographic histories reliably. Therefore, described species of Crotaphopeltis
and Philothamnus were investigated for their validity under the Evolutionary Species Concept with
an aim to identify cryptic species that are otherwise masked by phenotypic and/or ecological
parallels. Newly identified species were used in subsequent analysis of timing of lineage
diversification and the reconstruction of ancestral habitat states. The influence of historical
environmental conditions on the evolution of the climatic niche of two wide-ranging species in each
of the genera, C. hotamboeia and P. angolensis were additionally studied. The climatic
distributions of the two species were modelled for contrasting climatic conditions during the
Pleistocene period and their ancestral climatic states were reconstructed. Results show that both
genera are monophyletic. Up to seven candidate species are recognised within Philothamnus and two
within Crotaphopeltis, which provide a basis for future taxonomic revisions. Timing of lineage
diversification and associated shifts of species into novel habitats correspond to the historical
developments of the forest and savanna biomes, since the Oligocene. Philothamnus showed an
ancestral preference toward closed habitat, while the ancestral habitat type for Crotaphopeltis was
equivocal between closed and open habitat types. The Miocene epoch signifies a period of increased
diversity within both genera. It specifically appears that the climatic oscillations during
Early/Mid-Miocene facilitated the evolution of C. hotamboeia as a climatic generalist, whilst the
Late-Miocene climatic conditions induced specialisation of P. angolensis in subtropical climate.
The research presented here demonstrates that development of habitat throughout the Late Oligocene
influenced the radiation patterns of the colubrid snake genera, Crotaphopeltis and Philothamnus.AFRIKAANSE OPSOMMING: Die veranderlike landskap van die Afrika-vasteland is voorafgegaan deur 'n pan-Afrika-woud wat deur
die aaneenlopende en ossilerende inkrimping en uitbreidings van hierdie biome verander is sedert
die Oligoseen-epog, tot hoofsaaklik die huidige savanna. Sodanig kan die diere groepe wat tydens
die Paleogene/Neogene periode onstaan het met spesies wat in beide die woud- en savanna habitatte
voorkom genetiese kenmerke toon van die moontlike evolusionêre impak van hierdie biome se
ontwikkelings. Crotaphopeltis en Philothamnus was ideale kandidaat-taxa om die evolusionêre impak
van hierdie verskeie bioom-ontwikkelings op wydverspreide Afrika colubrid-slange te ondersoek.
Spesies in hierdie twee genera kom wyd-verspreid in sub-Sahara Afrika voor en word geassosieer met
óf beskutte (woud) óf oop (bv. savanna) sowel as albei habitat soorte. Die hoof navorsingsdoel was
om gesinkroniseerde tydsberekening en patrone van radiasie vir Crotaphopeltis en Philothamnus met
betrekking tot die ontwikkelingsgang van hierdie Afrika-biome te ondersoek. Inligting rakend die
evolusionêre verhoudings vir die twee genera was nodig om hul biogeografiese geskiedenisse
betroubaar saam te stel. Daarom is reeds beskryfde spesies van Crotaphopeltis en Philothamnus,
ondersoek vir hul geldigheid onder die Evolusionêre Spesies Konsep met die doel om kriptiese
spesies te identifiseer wat andersins deur fenotipiese en/of ekologiese parallelle verdoesel kan
word. Nuut geïdentifiseerde spesies is gebruik in die daaropeenvolgende analise van die
tydsberekening van diversifisering en die heropbou van voorouer-habitat toestande. Die invloed van
historiese omgewingstoestande op die evolusie van die klimaatsnisse van twee wydverspreide spesies
in elk van die genera, C. hotamboeia en P. angolensis, is verder bestudeer. Die
klimaatsverspreiding van die twee spesies is gemodelleer vir kontrasterende klimaatstoestande
gedurende die Pleistoseen- tydperk en hul voorouer klimaatstoestande is herbou. Resultate toon dat
beide genera monofileties is. Soveel as sewe kandidaat spesies word herken binne Philothamnus en
twee binne Crotaphopeltis wat 'n basis vorm vir toekomstige taksonomiese hersienings. Die
tydsberekeninge van diversifisering en die gepaardgaande verskuiwings van spesies na nuwe habitatte
stem ooreen met die historiese ontwikkelinge van die woud en savanna biome, sedert die Oligoseen.
Philotamnus toon ‘n voorouer voorkeur vir beskutte habitat tipes, terwyl die voorouer habitat tipe
vir Crotaphopeltis ewekansig was tussen beskutte en oop habitatsoorte. Die Mioseen-epog dui op 'n
tydperk van toenemende diversiteit binne beide genera. Dit blyk spesifiek dat die
klimaat-ossillasies tydens die Vroeë/Middel-Mioseen die evolusie van klimaats-veralgemening
fasiliteer het vir C. hotamboeia , terwyl die Laat-Mioseen klimaat spesialisasie van P. angolensis
in subtropiese klimaat veroorsaak het. Die navorsing wat hier aangebied word toon dat die
habitatsontwikkeling van die die Laat Oligoseen die radiasie patrone van die colubrid-slanggenera,
Crotaphopeltis en Philothamnus beïnvloed het.Doctora
Systematics of the Cape legless skink Acontias meleagris species complex
Get PDFThesis (MSc)--Stellenbosch University, 2013.This study examined the biogeography and taxonomic status of the Cape legless skink, Acontias meleagris species complex using phylogenetic analyses, population genetics, demographic history aspects, time of lineage diversification estimation, environmental statistic analyses and a morphological evaluation. A total of 231 specimens from 55 localities were collected from the entire known distribution range of the A. meleagris complex throughout the Eastern, Northern and Western Cape, South Africa. Partial sequence data were collected from two mitochondrial DNA loci, 16S rRNA and cytochrome oxidase subunit one (COI), and one protein-coding nuclear DNA locus, exophilin 5 (EXPH 5). DNA sequences were analyzed for phylogenetic methods and biogeographical dating, while population genetic analyses were conducted on the COI sequences. Geographical boundaries amongst cryptic lineages were determined and evolutionary drivers of cladogenesis within the species complex were inferred. Marked genetic structure was observed within the A. meleagris complex, and five clades were retrieved, most of which were statistically well supported. These five clades were also evident within the haplotypic analyses and were characterized by demographic stability.
Lineage diversification and the current biogeographical patterning observed for lineages within the A. meleagris species complex reflect the impact of sea level oscillations on historical coastal habitat availability. Additional historical evolutionary drivers within this subterranean species complex were inferred and discussed. The five clades within this species complex were considered discrete species, characterised by phylogenetic and biogeographic distinctiveness. While, morphological characters that could be used to identify the five species demonstrated widespread overlap for morphometric and meristic characters as well as colour pattering. Consequently, the phylogenetic species concept was employed for a taxonomical revision of A. meleagris sensu lato. Here, three of the previously recognised subspecies A. m. meleagris, A. m. orientalis and A. m. orientalis–'lineicauda' were elevated to full species, and two new species A. caurinus sp. nov. and A. parilis sp. nov. were described.National Research Foundation (NRF
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
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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