Distribution of veld rat sibling species <i>Aethomys chrysophilus</i> and <i>Aethomys ineptus</i> (Rodentia: Muridae) in southern Africa

Linzey, Alicia V.; Kesner, Michael H.; Chimimba, Christian T.; Newbery, C.

doi:10.1080/15627020.2003.11657205

Cited by 13 publications

(30 citation statements)

References 7 publications

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“…All small mammals caught were identified (Skinner and Chimimba 2005), aged and sexed, their sexual condition was determined and standard external measurements were recorded; after being marked with a unique semi-permanent fur clip for identification (Gunnell and Flowerdew 1990), they were released at the point of capture. Small ear clip samples from ten randomly selected specimens of the genera Aethomys and Mastomys, whose sibling species are otherwise externally indistinguishable (Linzey et al 2003;Russo et al 2006;Skinner and Chimimba 2005;Venturi et al 2004), were collected for identification via mitochondrial DNA analysis. All Mastomys and Aethomys samples were genetically identified as M. coucha and A. ineptus, respectively.…”

Section: Small Mammal Surveyingmentioning

confidence: 99%

Untangling the roles of fire, grazing and rainfall on small mammal communities in grassland ecosystems

et al. 2007

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In grassland systems across the globe, ecologists have been attempting to understand the complex role of fire, grazing and rainfall in creating habitat heterogeneity and the consequences of anthropogenic control of these factors on ecosystem integrity and functioning. Using a South African grassland ecosystem as a model, we investigated the impact of fire and grazing pressure on small mammal communities during three differing periods of a rainfall cycle. Over 2 years, 15,203 trap nights revealed 1598 captures of 11 species (nine rodents, one macroscelid and one insectivore). Results highlighted the importance of the interplay between factors and showed that the role of fire, grazing and rainfall in determining small mammal abundance was species-dependant. While no two species were affected by the same environmental variables, grass cover or height was important to 56% of species. Considered independently, high rainfall had a positive influence on small mammal abundance and diversity, although the lag period in population response was species-specific. High grazing negatively affected overall abundance, but specifically in Mastomys coucha; fire alone had little immediate impact on small mammal diversity. Six months after the fire, vegetation cover had recovered to similar levels as unburned areas, although small mammal diversity and richness were higher in burned areas than unburned areas. Grazing levels influenced the rate of vegetation recovery. In conclusion, low-level grazing and burning can help to maintain small mammal biodiversity, if conducted under appropriate rainfall levels. A too high grazing pressure, combined with fire, and/or fire conducted under drought conditions can have a negative impact on small mammal biodiversity. To maintain small mammal diversity in grassland ecosystems, the combined effects of the previous year's rainfall and existing population level as well as the inhibition of vegetation recovery via grazing pressure need to be taken into consideration before fire management is applied.

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Section: Small Mammal Surveyingmentioning

confidence: 99%

Untangling the roles of fire, grazing and rainfall on small mammal communities in grassland ecosystems

et al. 2007

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“…niloticus was based on the identification key of Delany (1975) and the genetic data of Abdel-Rahman (2005) while that of Ae. ineptus was based on the geographic distributional limits in South Africa delineated by Linzey et al (2003) based on positively identified specimens using cytogenetic, allozyme, mitochondrial DNA (mtDNA) cytochrome b (cyt b), and sperm morphological data. Most of the specimens in our study formed part of the samples analysed by previous traditional morphometric analyses of Ar.…”

Section: Species Identificationmentioning

confidence: 99%

“…Aethomys ineptus occurs in northeastern South Africa, and the area south of about 251S, with its southern limit approximately south of Durban, KwaZulu-Natal Province (30103 0 S) (Linzey et al 2003), while Ar. niloticus is widespread in East, Central and West Africa, the Nile Valley, and in the Horn of Africa (Musser and Carleton 2005).…”

Section: Introductionmentioning

confidence: 99%

Geometric craniometric analysis of sexual dimorphism and ontogenetic variation: A case study based on two geographically disparate species, Aethomys ineptus from southern Africa and Arvicanthis niloticus from Sudan (Rodentia: Muridae)

Abdel-Rahman

Taylor²,

Contrafatto

et al. 2009

Mammalian Biology

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Non-geographic morphometric variation, particularly at the level of sexual dimorphism and ontogenetic (agerelated) variation, has been documented in rodents, and useful for establishing whether to analyse sexes separately or together, and for selecting adult specimens for subsequent data recording and analysis. However, such studies have largely been based on traditional morphometric analyses of linear measurements that mainly focus on overall size, rather than shape-related morphometric variation. Unit-free, landmark/outline-based geometric morphometric analyses are considered to offer a more appropriate tool for assessing shape-related morphometric variation. In this study, we used geometric cranial morphometric analysis to assess the nature and extent of sexual dimorphism and age variation within the Tete veld rat, Aethomys ineptus (Thomas and Wroughton, 1908) from southern Africa and the African Nile rat, Arvicanthis niloticus (Desmarest, 1822) from Sudan. The results obtained were in turn compared with previously published results based on independent geometric and traditional cranial morphometric data from the same sampled populations examined in the present study. While our geometric morphometric results detected statistically significant sexual dimorphism in cranial shape within Ar. niloticus only, previously published results based on traditional morphometric data failed to detect significant sexual dimorphism within this species. However, similar to previously published traditional morphometric data, our geometric morphometric results detected statistically significant age-related variation in cranial shape and size within both Ae. ineptus and Ar. niloticus, with individuals of age classes 5 and 6 being considered to represent adult specimens. Our results highlight the importance of carefully evaluating both size-and shape-related non-geographic morphometric variation prior to the analysis of geographic variation and the delineation of species. Erroneous conclusions of non-geographic variation may have implications in the interpretation of geographic and evolutionary processes that may be responsible for morphological differences at both the inter-and intra-specific levels.

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“…Cranial morphometric analysis of positively identified specimens (2n 5 44, n 5 4; 2n 5 50, n 5 15), augmented by specimens from the same localities (2n 5 44, n 5 34; 2n 5 50, n 5 6), revealed the following diagnostic characters for the 2n 5 44 cytotype (A. ineptus) relative to the 2n 5 50 cytotype (A. chrysophilus): alisphenoid process of squamosal significantly narrower, and ratio of greatest cross-sectional crown width of M2 to greatest length of frontals averages 16.2% versus 17.4% and ratio of greatest cross-sectional crown width of m2 to greatest length of frontals 15.0% versus 16.3% (Chimimba 1998;Chimimba et al 1999). However, species assignments of museum specimens based on these characters result in geographic distributions that are contradicted by those based on a larger number of positively identified specimens from an array of localities (Linzey et al 2003) and need to be reexamined.…”

Section: Diagnosismentioning

confidence: 82%

“…Positive identification of A. ineptus requires examination of spermatozoa, the heads of which are spatulate (A. chrysophilus has a falciform-shaped sperm head- Breed et al 1988;Visser and Robinson 1987); determination of diploid chromosome number (2n 5 44 in A. ineptus, 2n 5 50 in A. chrysophilus- Gordon and Rautenbach 1980); allozyme analysis (hemoglobin of A. ineptus with either ''fast '' or ''slow'' bands, A. chrysophilus with only ''slow'' bands-G. Campbell, in litt. ); or analysis of mitochondrial DNA (mtDNA- Linzey et al 2003;Russo et al 2006). Cranial morphometric analysis of positively identified specimens (2n 5 44, n 5 4; 2n 5 50, n 5 15), augmented by specimens from the same localities (2n 5 44, n 5 34; 2n 5 50, n 5 6), revealed the following diagnostic characters for the 2n 5 44 cytotype (A. ineptus) relative to the 2n 5 50 cytotype (A. chrysophilus): alisphenoid process of squamosal significantly narrower, and ratio of greatest cross-sectional crown width of M2 to greatest length of frontals averages 16.2% versus 17.4% and ratio of greatest cross-sectional crown width of m2 to greatest length of frontals 15.0% versus 16.3% (Chimimba 1998;Chimimba et al 1999).…”

Section: Diagnosismentioning

confidence: 99%

Aethomys ineptus (Rodentia: Muridae)

Chimimba

Linzey

2008

Mammalian Species

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Aethomys ineptus (Thomas and Wroughton, 1908), commonly called the Tete veld rat, is a medium-sized rodent with a long, sparsely haired tail and spermatozoa with spatulate-shaped heads (unique for all muroid rodents thus far examined). A. ineptus co-occurs with its sibling species, A. chrysophilus, and in areas of co-occurrence, an examination of spermatozoa, diploid number, allozymes, or mitochondrial DNA is required to distinguish the 2. Previous work described as many as 11 species of Aethomys, but recent evidence indicates a need for taxonomic revision of the genus. Endemic to Africa, A. ineptus prefers habitats where there is substantial cover in the form of shrubs, rocks, and herbaceous vegetation. It is not of special conservation concern.

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Distribution of veld rat sibling species Aethomys chrysophilus and Aethomys ineptus (Rodentia: Muridae) in southern Africa

Cited by 13 publications

References 7 publications

Untangling the roles of fire, grazing and rainfall on small mammal communities in grassland ecosystems

Untangling the roles of fire, grazing and rainfall on small mammal communities in grassland ecosystems

Geometric craniometric analysis of sexual dimorphism and ontogenetic variation: A case study based on two geographically disparate species, Aethomys ineptus from southern Africa and Arvicanthis niloticus from Sudan (Rodentia: Muridae)

Aethomys ineptus (Rodentia: Muridae)

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