McLeish M.J.,Stellenbosch University |
Van Noort S.,Iziko South African Museum |
Van Noort S.,University of Cape Town
BMC Evolutionary Biology | Year: 2012
Background: The interaction between insects and plants takes myriad forms in the generation of spectacular diversity. In this association a species host range is fundamental and often measured using an estimate of phylogenetic concordance between species. Pollinating fig wasps display extreme host species specificity, but the intraspecific variation in empirical accounts of host affiliation has previously been underestimated. In this investigation, lineage delimitation and codiversification tests are used to generate and discuss hypotheses elucidating on pollinating fig wasp associations with Ficus. Results: Statistical parsimony and AMOVA revealed deep divergences at the COI locus within several pollinating fig wasp species that persist on the same host Ficus species. Changes in branching patterns estimated using the generalized mixed Yule coalescent test indicated lineage duplication on the same Ficus species. Conversely, Elisabethiella and Alfonsiella fig wasp species are able to reproduce on multiple, but closely related host fig species. Tree reconciliation tests indicate significant codiversification as well as significant incongruence between fig wasp and Ficus phylogenies. Conclusions: The findings demonstrate more relaxed pollinating fig wasp host specificity than previously appreciated. Evolutionarily conservative host associations have been tempered by horizontal transfer and lineage duplication among closely related Ficus species. Independent and asynchronistic diversification of pollinating fig wasps is best explained by a combination of both sympatric and allopatric models of speciation. Pollinator host preference constraints permit reproduction on closely related Ficus species, but uncertainty of the frequency and duration of these associations requires better resolution. © 2012 McLeish and van Noort; licensee BioMed Central Ltd.
McLeish M.J.,Stellenbosch University |
McLeish M.J.,South African National Biodiversity Institute |
Van Noort S.,Iziko South African Museum |
Tolley K.A.,South African National Biodiversity Institute
Molecular Ecology | Year: 2010
Ecological processes are manifest in the evolution and form of phenotype diversity. The great abundance of parasitoid species has led to speculation whether rates of speciation and extinction are dependent on parasitoid diversity. If these factors are mutually exclusive, species diversity should fluctuate instead of remaining relatively constant over time. It is not known whether radiations constrained by coevolutionary interactions conform to density-dependent diversification processes. Here we test the prediction that parasitoid fig wasp diversification responds to changes in ecological opportunity and density-independent processes. A phylogenetic approach is used to estimate relative divergence times and infer diversification rate changes using γ-statistics. Monte Carlo constant rates tests that accommodate incomplete sampling could not reject constant rates diversification. Parasitoid fig wasp diversification is consistent with a more complex explanation than density-dependent cladogenesis. The results suggest contemporary African parasitoid fig wasp diversity remains a legacy of an ancient ecological opportunity facilitated by fig tree diversification following the breakup of Pan-African forests and evolution of the savanna biome over the last 55 Ma and the more recent aridification of the African continent in the last 5 Ma. These results imply that amplified phenotypic differentiation of specialist insects coevolving with plants is coupled to evolutionarily infrequent changes in ecological opportunity. © 2010 Blackwell Publishing Ltd.
Mcleish M.,Stellenbosch University |
Guo D.,South African National Biodiversity Institute |
van Noort S.,Iziko South African Museum |
van Noort S.,University of Cape Town |
Midgley G.,South African National Biodiversity Institute
New Phytologist | Year: 2011
The fig tree-fig wasp obligate pollination mutualism has strong ancestral affinities with tropical communities, but is present in much drier contemporary biomes, especially at higher latitudes at the edge of their range. The extent to which adaptation to environmental variables is evolutionarily conserved and whether environmental differences function in ecological speciation of the mutualism are unknown. Here we use climate models and phylogenetic reconstructions to test whether the Ficus-fig wasp mutualism has adapted and radiated into drier climates and led to ecological speciation in both plant and insect. The results showed phylogenetic correspondence between closely related Ficus species with either savanna, forest, or riparian habitat categories, were most strongly explained by both climate and environmental variables. Rare episodes of adaptation to dry apotypic conditions have resulted in substantial radiations into savanna. Inferences were consistent with predictions of niche conservatism and support the postulate that ecological speciation of the mutualism occurs, but under contrasting and intertwined circumstances among plant-pollinator adaptation and tolerance to the environment. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.
McLeish M.J.,Chinese Academy of Sciences |
Beukman G.,Stellenbosch University |
Van Noort S.,Iziko South African Museum |
Van Noort S.,University of Cape Town |
Wossler T.C.,Stellenbosch University
PLoS ONE | Year: 2014
Parasitoid diversity in terrestrial ecosystems is enormous. However, ecological processes underpinning their evolutionary diversification in association with other trophic groups are still unclear. Specialisation and interdependencies among chalcid wasps that reproduce on Ficus presents an opportunity to investigate the ecology of a multi-trophic system that includes parasitoids. Here we estimate the host-plant species specificity of a parasitoid fig wasp genus that attacks the galls of nonpollinating pteromalid and pollinating agaonid fig wasps. We discuss the interactions between parasitoids and the Ficus species present in a forest patch of Uganda in context with populations in Southern Africa. Haplotype networks are inferred to examine intraspecific mitochondrial DNA divergences and phylogenetic approaches used to infer putative species relationships. Taxonomic appraisal and putative species delimitation by molecular and morphological techniques are compared. Results demonstrate that a parasitoid fig wasp population is able to reproduce on at least four Ficus species present in a patch. This suggests that parasitoid fig wasps have relatively broad host- Ficus species ranges compared to fig wasps that oviposit internally. Parasitoid fig wasps did not recruit on all available host plants present in the forest census area and suggests an important ecological consequence in mitigating fitness trade-offs between pollinator and Ficus reproduction. The extent to which parasitoid fig wasps exert influence on the pollination mutualism must consider the fitness consequences imposed by the ability to interact with phenotypes of multiple Ficus and fig wasps species, but not equally across space and time. ©2012 McLeish et al.
Buffington M.L.,U.S. Department of Agriculture |
Brady S.G.,Smithsonian Institution |
Morita S.I.,Smithsonian Institution |
Morita S.I.,North Carolina State University |
And 2 more authors.
Systematic Entomology | Year: 2012
We examine the phylogenetic relationships of Figitidae and discuss host use within this group in light of our own and previously published divergence time data. Our results suggest Figitidae, as currently defined, is not monophyletic. Furthermore, Mikeiinae and Pycnostigminae are sister-groups, nested adjacent to Thrasorinae, Plectocynipinae and Euceroptrinae. The recovery of Pycnostigminae as sister-group to Mikeiinae suggests two major patterns of evolution: (i) early Figitidae lineages demonstrate a Gondawanan origin (Plectocynipinae: Neotropical; Mikeiinae and Thrasorinae: Australia; Pycnostigminae: Africa); and (ii) based on host records for Mikeiinae, Thrasorinae and Plectocynipinae, Pycnostigminae are predicted to be parasitic on gall-inducing Hymenoptera. The phylogenetic position of Parnips (Parnipinae) was unstable, and various analyses were conducted to determine the impact of this uncertainty on both the recovery of other clades and inferred divergence times; when Parnips was excluded from the total evidence analysis, Cynipidae was found to be sister-group to [Euceroptrinae + (Plectocynipinae (Thrasorinae + (Mikeiinae + Pycnostigminae)))], with low support. Divergence dating analyses using BEAST indicate the stem-group node of Figitidae to be c. 126 Ma; the dipteran parasitoids (Eucoilinae and Figitinae), were estimated to have a median age of 80 and 88 Ma, respectively; the neuropteran parasitoids (Anacharitinae), were estimated to have a median age of 97 Ma; sternorrhynchan hyperparasitoids (Charipinae), were estimated to have a median age of 110 Ma; the Hymenoptera-parasitic subfamilies (Euceroptinae, Plectocynipinae, Trasorinae, Mikeiinae, Pycnostigminae, and Parnipinae), ranged in median ages from 48 to 108 Ma. Rapid radiation of Eucoilinae subclades appears chronologically synchronized with the origin of their hosts, Schizophora (Diptera). Overall, the exclusion of Parnips from the BEAST analysis did not result in significant changes to divergence estimates. Finally, though sparsely represented in the analysis, our data suggest Cynipidae have a median age of 54 Ma, which is somewhat older than the age of Quercus spp (30-50 Ma), their most common host. © 2012.
Matthews T.,Iziko South African Museum |
Stynder D.D.,University of Cape Town
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2011
Subsequent to the initial description of two Aethomys species (Aethomys adamanticola and Aethomys modernis) at the Early Pliocene site of Langebaanweg (LBW), an increase in sample size led to the secure identification of a third, as yet, undescribed species. In addition to this new species, three morphs of existing species, or possibly three new species, were also recognized. Geometric morphometrics was used to explore the relationship of fossil species and morphs with extant Aethomys species, and to assess the intra and inter-specific variation in the size and shape of modern, as well as the LBW, Aethomys specimens. Geometric morphometrics indicates a marked similarity in the upper first molar (M1) shape between all the analyzed species, extant and extinct, and suggests the persistence, over a significant period of time, of a prototype Aethomys M1 shape. The relative warp analyses indicate some overlap in shape between the two modern species, Aethomys chrysophilus and Aethomys namaquensis, as well as some inter-specific variation. These two species differ significantly from one another in terms of size. Variability in terms of size and to a minor extent, shape, was also evident in the fossil Aethomys, and it was concluded that the various fossil morphs investigated did not represent new species, or intra-specific sexual dimorphism, but rather, intra-specific variability in size and shape. Interestingly, the newly-identified LBW Aethomys species, which is similar in appearance to the extant east African Aethomys kaiseri, also showed a similarity in shape and size to A. adamanticola. These results indicate that geometric morphometrics has limitations when differentiating between morphologically similar species. The presence of Aethomys in Namibia at around 10.5 to 9.5Ma, the degree of speciation of Aethomys at LBW, and the similarity of the LBW fossil species to the modern ones (including an East African species), provides good evidence for a southern African origin for modern Aethomys. © 2011 Elsevier B.V.
A new specimen of Promoschorhynchus (Therapsida: Therocephalia: Akidnognathidae) from the Lower Triassic of South Africa and its implications for theriodont survivorship across the Permo-Triassic boundary
Huttenlocker A.K.,University of Washington |
Sidor C.A.,University of Washington |
Smith R.M.H.,Iziko South African Museum
Journal of Vertebrate Paleontology | Year: 2011
The anatomy of a new subadult specimen of eutherocephalian therapsid, attributed to Promoschorhynchus cf. P. platyrhinus, is described from lowermost Triassic Lystrosaurus Assemblage Zone strata in the main Karoo Basin of South Africa. The specimen preserves information previously unknown in the genus, including details of the posterior region of the skull and intertemporal region, and a partial (though disarticulated) postcranial skeleton. A cladistic analysis of 32 therapsid taxa, including 24 Permo-Triassic therocephalian genera, and 121 craniodental and postcranial characters supports the specimen's placement within the Permian akidnognathid genus Promoschorhynchus (making it the youngest documented occurrence of this taxon) within a monophyletic Therocephalia. Inclusion of new postcranial characters strengthens support of the therocephalian clade. The new record of Promoschorhynchus offers insights into the diversity of eutheriodonts across the Permo-Triassic boundary (PTB) in the Karoo Basin. In contrast to cynodonts, therocephalians exhibited decreased rates of cladogenesis across the PTB, with several Triassic lineages having roots in the Late Permian rather than representing earliest Triassic radiations. © 2011 by the Society of Vertebrate Paleontology.
Kennedy W.J.,University of Oxford |
Klinger H.C.,Iziko South African Museum
African Natural History | Year: 2012
Three taxa of desmoceratoid ammonites are recognized in the Lower Albian of northern KwaZulu-Natal, all of them previously known only from Madagascar: Moretella sp., Beudanticeras komihevitraense Collignon, 1950, and Aioloceras besairiei (Collignon, 1949). Madagascan type and figured material, much of it difficult to interpret from the original figures is re-illustrated, and the intraspecific variation and dimorphism in Moretella and Aioloceras are documented.
Rousse P.,Iziko South African Museum |
Van Noort S.,Iziko South African Museum
Zootaxa | Year: 2013
We revise the Afrotropical Lycorininae and describe Lycorina yui Rousse & van Noort sp. nov. from South Africa. An illustrated key to Lycorininae species of the Afrotropical region is provided. Lycorina continentalis (Benoit, 1953) is considered a junior synonym of Lycorinafici Seyrig, 1932, and is newly reported from Uganda and South Africa. Online dichotomous and interactive Lucid keys are available at http://www.waspweb.org.
Asher R.J.,University of Cambridge |
Margaret Avery D.,Iziko South African Museum
Palaeontologia Electronica | Year: 2010
We describe new material of fossil golden moles (Chrysochloridae) from the early Pliocene site of Langebaanweg, South Africa. This site has produced hundreds of isolated craniodental and postcranial elements, all of which are easily identifiable as chrysochlorid. Based on size and morphology, at least three species are represented in this assemblage, two of which are represented by material of sufficient quality to name. Based on relative abundance, humeral and mandibular types can be associated with other material. Craniodentally, the most common Langebaanweg species closely resembles the extant Cape golden mole, Chrysochloris asiatica, but differs in showing a relatively narrow distal humerus, proportionally similar to that of the extant Eremitalpa granti. A second, rarer species is represented by two well-preserved mandibles that exhibit a stout, enlarged lower second incisor, a robust mandibular corpus, and is associated with a less common humeral type that resembles living Chrysochloris. At least one additional species is represented by a small number of relatively large humeri, femora, and scapular fragments. Because it lacks any craniodental representation, it is not named in this paper. We tentatively suggest that the relatively narrow distal margin of the humerus of the new, C. asiatica-like species may have been adapted to a habitat similar to that of the modern E. granti, a "sand-swimming" golden mole currently known from northwestern South Africa and southern Namibia. © Paleontological Association March 2010.