Identification of cryptic species of rodents<i>(Mastomys, Aethomys, Saccostomus)</i>in the Kruger National Park

Gordon, D. H.; Watson, Christine

doi:10.1080/02541858.1986.11447965

Cited by 35 publications

(40 citation statements)

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“…By combining the above data with those previously published on sperm morphology of murine rodents in the African (Bishop and Austin, 1957;Gordon and Watson, 1986;Breed, 1995a,b) and Australasian (Breed, 1984(Breed, , 1997Breed and Aplin, 1994) clades, and by comparing these data to a phylogeny based on microcomplement fixation of albumin (Watts and Baverstock, 1995), it is now possible to propose a scenario for the evolution of sperm form within the murine subfamily of rodents (Fig. 9).…”

Section: Discussionmentioning

confidence: 90%

“…Subsequent studies on many other murine rodent species in the African (Bishop and Austin, 1957;Gordon and Watson, 1986;Visser and Robinson, 1987;Breed, 1995a), New Guinean, and Australasian (Breed, 1984(Breed, , 1997Breed and Aplin, 1994) clades have shown that considerable interspecific diversity in sperm morphology exists in each of these clades, although most species have a sperm head with an apical hook. In the present study the morphology of the spermatozoon, as shown by electron microscopy, of species from four clades of murine rodents occurring in Eurasia is given.…”

Section: Discussionmentioning

confidence: 96%

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The spermatozoon of Eurasian murine rodents: Its morphological diversity and evolution

Breed

2004

Journal of Morphology

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The murine rodents are the most speciose subfamily of mammals. Here the morphology of the spermatozoon, as determined by scanning and transmission electron microscopy of representative species from four Eurasian clades, is described. Much interspecific variability in all components of the spermatozoon was found to occur, although most species have a bilaterally flattened sperm head with a single apical hook of variable length and orientation. Ultrastructural observations indicate that this apical hook invariably contains a nuclear projection as well as a large extension of the subacrosomal cytoskeleton, as a perforatorium rostrally, and a complex asymmetrical acrosomal extension. These spermatozoa also have relatively long tails that are attached to the lower concave surface of the sperm head. Uniquely, in species in the Apodemus clade, the apical hook is orientated caudally. In a few species a highly derived sperm head morphotype that does not contain an apical hook is present. These sperm heads vary in morphology from being globular in two species of Bandicota, to bilaterally flattened and paddle-shaped in Tokudaia and Micromys. In spermatozoa of the latter two genera the subacrosomal cytoskeleton, which is less extensive than in species with a hooked sperm head, forms an apical extension, but that is not the case in Bandicota. In all species where the sperm head lacks an apical hook the acrosome is more symmetrical. The sperm tail is much shorter in these species, with attachment to the head occurring on the ventral surface in Tokudaia and basal in Micromys and the two species of Bandicota. As the sperm head morphotype with a complex apical hook is present in all the major clades of murine rodents, it is likely to be a plesiomorphic character within each of these clades, with the nonhooked sperm heads, which vary greatly in structure between species of the different lineages, probably being independently derived. The ultrastructural organization of the sperm head of Bandicota, but not those of Micromys or Tokudaia, suggest divergence in some of the morphological events associated with sperm-egg interaction at the time of fertilization.

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Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 96%

The spermatozoon of Eurasian murine rodents: Its morphological diversity and evolution

Breed

2004

Journal of Morphology

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“…These two cytotypes have also been reported to differ in sperm and bacular morphology, reproductive behaviour, pheromones and ultrasonic vocalization (Skinner and Smithers, 1990;Musser and Carleton, 1993;Smit et al, 2001). All these differences, together with the absence of hybrids in areas of sympatry, strongly suggested reproductive isolation between the two types (Gordon and Watson, 1986). Despite the reported differences, the two cryptic species referred to the nominated species M. natalensis for the n = 32 cytotype and M. coucha for n = 36 cytotype (Musser and Carleton, 1993) cannot easily be distinguished by qualitative external and/or cranial morphology (Gordon and Watson, 1986).…”

Section: Introductionmentioning

confidence: 95%

“…All these differences, together with the absence of hybrids in areas of sympatry, strongly suggested reproductive isolation between the two types (Gordon and Watson, 1986). Despite the reported differences, the two cryptic species referred to the nominated species M. natalensis for the n = 32 cytotype and M. coucha for n = 36 cytotype (Musser and Carleton, 1993) cannot easily be distinguished by qualitative external and/or cranial morphology (Gordon and Watson, 1986). However, a subsequent study by Dippenaar et al (1993) revealed subtle cranial morphometric differences between the two sibling species, but cautioned that such data need to be carefully evaluated before being applied, due to potential influence of geographic variation over the species' distribution ranges.…”

Section: Introductionmentioning

confidence: 99%

“…Mastomys natalensis (sensue lato) occurs commonly throughout most of South Africa. It was incorrectly considered as a single species but cytogenetically and electrophoretical studies during the late 1970s and early 1980s revealed the presence of two electrophoretically distinct types (2n = 32/"slow" hemoglobin electromorph and 2n = 36/ "fast" hemoglobin electeromorph), (Green et al, 1980;Gordon and Watson, 1986). These two cytotypes have also been reported to differ in sperm and bacular morphology, reproductive behaviour, pheromones and ultrasonic vocalization (Skinner and Smithers, 1990;Musser and Carleton, 1993;Smit et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Daily rhythms of body temperature and heat production of sibling mastomys species from different ecosystems — The response to photoperiod manipulations

Haim

Zubidat

Aarde

2008

Comparative Biochemistry and Physiology Part A: Molecular &

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We compared body temperature (T b ) and metabolic rates, measured as oxygen consumption (VO 2 ), daily rhythms of two sibling species of the genus Mastomys. We also studied their responses to long day (16L: 8D, LD) and short day (8L: 16D, SD) photoperiod manipulations at a constant ambient temperature of 26 + 1°C. We noted significant differences in T b and VO 2 daily rhythm patterns, under SD and LD-acclimation between the sibling species. These differences explain adaptation to the climatic conditions that prevail in the different ecosystems where these species live. To the best of our knowledge, this is the first time that physiological differences between the two siblings are measured by using chronobiological methods.

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Sperm head structure of a murid rodent from Southern Africa: The red veld rat Aethomys chrysophilus

et al. 1988

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The morphology of spermatozoa from the red veld rat, Aethomys chrysophilus, of Southern Africa is described; two very different types were found, which came from animals from two separate, as-yet-undescribed, species. In individuals from South Africa the sperm head had a somewhat disc-shaped nucleus and a large acrosome with a huge apical segment that, during epididymal transit, changed in form from initially projecting anteriorly to a highly complex structure that was flexed caudad and lay alongside part of the rest of the sperm head. In addition, the chromatin generally appeared to be not fully condensed. Spermatozoa from animals collected in Malawi were very different in morphology and had a head with a typical apical hook, a perforatorium, fully condensed chromatin, and a 4-micron-long ventral spur. Its sperm tail was also significantly longer. The time of divergence of these two groups of animals from a common ancestor is not known, but the present results show that a considerable morphological change in the sperm nucleus, acrosome, and subacrosomal space can evolve even between two, presumably closely related, species.

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Identification of cryptic species of rodents(Mastomys, Aethomys, Saccostomus)in the Kruger National Park

Cited by 35 publications

References 1 publication

The spermatozoon of Eurasian murine rodents: Its morphological diversity and evolution

The spermatozoon of Eurasian murine rodents: Its morphological diversity and evolution

Daily rhythms of body temperature and heat production of sibling mastomys species from different ecosystems — The response to photoperiod manipulations

Sperm head structure of a murid rodent from Southern Africa: The red veld rat Aethomys chrysophilus

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