114 research outputs found
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
Heemstede Huiskomitee, 1983
No full textPrimaria – M. van der Westhuizen.Donated by SRC.Published in Stellenbosse Student, 1983.Front row: Mariaan van der Westhuizen (primaria), Ray Grundlingh (vice-primaria), Alet van Niekerk. Middle: Lyzette Monk, Anine Truter, Diane Scott, Nerine Engelbrecht, Elmi Badenhorst, Hanlie Beukes. Back: Marina Sieberhagen, Delia Cockerill, Hannie Carstens.Black and white photograph depicting the Heemstede house committee
Heemstede Huiskomitee, 1983
No full textPrimaria – M. van der Westhuizen.Donated by SRC.Published in Stellenbosse Student, 1983.Back row: Lyzette Monk, Hannie Carstens, Delia Cockerill, Nerine Engelbrecht, Anine Truter, Hanlie Beukes. Middle: Marina Sieberhagen, Diane Scott, Mariaan van der Westhuizen (primaria). Front: Alet van Niekerk, Ray Grundlingh (vice-primaria), Elmi Badenhorst.Black and white photograph depicting the Heemstede house committee
Perineural infiltration of the inferior alveolar nerve in mandibular ameloblastomas
No full textIntroduction: Ameloblastomas are locally aggressive with a high recurrence rate, warranting continuity jaw resection. The preservation of the inferior alveolar nerve during ablative surgery in the treatment of ameloblastoma is contentious. Studies have suggested salvaging the nerve by pulling it out of the tumour prior to resection. There are presently no studies that have explored the surgical merit of nerve preservation in the treatment of ameloblastomas.
Aim: To determine the histological association of mandibular solid and multicystic ameloblastoma to the inferior alveolar nerve, in situ and in separately removed segments of the nerve in order to determine the feasibility of preserving the nerve during ablative surgery for mandibular ameloblastomas.
Materials and Methods: 13 resected hemimandibulectomy specimens were histologically examined with respect to the course and association of the inferior alveolar canal/nerve and the ameloblastoma. In group 1 (8 patients) this association was examined with the nerve within the mandibular segment following resection whilst in group 2 (5 patients) the nerve was explanted from the resected tumour and examined separately. In group 1 the closest histologic distance between tumour cells and the inferior alveolar canal was measured.
Results: Perineural and intraneural ameloblastoma involvement of the inferior alveolar nerve was confirmed in 62.5% and 40% of cases in groups 1 and 2 respectively. Tumour cells were noted abutting directly onto the nerve in Group 1. Tumour cells were removed together with the pulled out nerve in Group 2. There was no correlation between the histological variants of ameloblastoma and the presence of tumour either in situ or within the pulled-out nerve bundle. Conclusion: Both peri- and intraneural involvement of the inferior alveolar nerve was histologically confirmed in solid and multicystic hemimandibular specimens both in situ within the tumour as well as in separately removed segments of the nerve. Preservation of the inferior alveolar nerve during ablative surgery for mandibular ameloblastomas cannot be advocated
Aspects of the biology of the pink-billed lark (Spizocorys conirostris) in the Limpopo Province, South Africa
No full textThesis (M.Sc. ( Zoology)) --University of Limpopo, 2013The fieldwork for this study was carried out from October 2008 to October 2010, under the supervision of Professor D. Engelbrecht of the Department of Biodiversity at the University of Limpopo. Professor Engelbrecht kindly agreed to provide me with raw breeding data of the same population collected during 2008. This study represents original work by the author and where work of other authors has been used; they are duly acknowledged in the text and listed as references.
Chapter 1 is a general introduction to the family Alaudidae in which their characteristics and taxonomy are discussed. This is followed by a brief overview of the general biology and ecology of larks of the world in general, followed by a more specific emphasis on the genus Spizocorys, and finally the Pink-billed Lark. In this section, gaps in the available knowledge of Pink-billed Larks are highlighted. This chapter culminates in the aim and objectives of this study. In Chapter 2 the various aspects of the breeding biology of the Pink-billed Lark are reported. This includes, amongst others, aspects such as breeding seasonality, clutch sizes, roles of the sexes during the breeding cycle and breeding success. Chapter 3 provides the results of a morphometric study of museum study skins from across the species range. This includes an analysis of sexual size dimorphism and geographical variation of the different subspecies. This chapter also provides a brief description of the timing and pattern of moult and the various vocalizations of the Pink-billed Lark. Chapter 4 concludes the dissertation with a summary of the results of this study and highlights avenues for future research on the species and the family.
The format of Chapters 2 and 3 takes the form of research papers that can be submitted for publication with minimum editing. Chapter 2 has been published in the Journal of African Zoology (see below). Chapter 3 is in preparation for submission to a peer-reviewed journal. As such, there is some repetition in the introductory paragraphs and concluding remarks of chapters 2, 3 and 4. To give this manuscript a degree of uniformity, the literature cited in all chapters has been formatted according to the manuscript requirements of the Journal of African Zoology, and a reference list appears at the end of the dissertation. Tables and figures are arranged at the end of each chapter
The radiation and biogeography of snakes across south-eastern Africa with respect to the evolution of the savanna biome
No full textThesis (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
No full textThesis (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
A fundamental study of the influence of aluminium on the white rusting of galvanized steel
No full textApplied Science
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