The Angolan free-tailed bat (Mops condylurus) uses roosts that often exceed 40 degrees C, an ambient temperature (Ta) that is lethal to many microchiropterans. We measured the physiological responses of this species at Ta's from 15 degrees to 45 degrees C. Torpor was commonly employed during the day at the lower Ta, but the bats generally remained euthermic at night, with a mean body temperature (Tb) of 35.2 degrees C. Metabolic rate reflected the pattern of Tb, increasing with falling Ta at night but decreasing during the day. Metabolic rate and evaporative losses were lower in torpid than in euthermic bats. Body temperature increased at each Ta >35 degrees C and was 43 degrees C at Ta of 45 degrees C. At Ta of 40 degrees C bats increased dry thermal conductance and evaporative heat loss compared to lower Ta. At 45 degrees C dry thermal conductance was lower than at 40 degrees C and evaporative heat loss was 132% of metabolic heat production. At high Ta there was only a slight increase in metabolic rate despite the employment of evaporative cooling mechanisms and an increase in Tb. Collectively our results suggest that M. condylurus is well suited to tolerate high Ta, and this may enable it to exploit thermally challenging roost sites and to colonise habitats and exploit food sources where less stressful roosts are limiting.
The naked mole‐rat (Heterocephalus glaber) has fascinated zoologists for at least half a century. It has also generated considerable biomedical interest not only because of its extraordinary longevity, but also because of unusual protective features (e.g. its tolerance of variable oxygen availability), which may be pertinent to several human disease states, including ischemia/reperfusion injury and neurodegeneration. A recent article entitled ‘Surprisingly long survival of premature conclusions about naked mole‐rat biology’ described 28 ‘myths’ which, those authors claimed, are a ‘perpetuation of beautiful, but falsified, hypotheses’ and impede our understanding of this enigmatic mammal. Here, we re‐examine each of these ‘myths’ based on evidence published in the scientific literature. Following Braude et al., we argue that these ‘myths’ fall into four main categories: (i) ‘myths’ that would be better described as oversimplifications, some of which persist solely in the popular press; (ii) ‘myths’ that are based on incomplete understanding, where more evidence is clearly needed; (iii) ‘myths’ where the accumulation of evidence over the years has led to a revision in interpretation, but where there is no significant disagreement among scientists currently working in the field; (iv) ‘myths’ where there is a genuine difference in opinion among active researchers, based on alternative interpretations of the available evidence. The term ‘myth’ is particularly inappropriate when applied to competing, evidence‐based hypotheses, which form part of the normal evolution of scientific knowledge. Here, we provide a comprehensive critical review of naked mole‐rat biology and attempt to clarify some of these misconceptions.
BackgroundGolden moles (Chrysochloridae) are small, subterranean, afrotherian mammals from South Africa and neighboring regions. Of the 21 species now recognized, some (e.g., Chrysochloris asiatica, Amblysomus hottentotus) are relatively common, whereas others (e.g., species of Chrysospalax, Cryptochloris, Neamblysomus) are rare and endangered. Here, we use a combined analysis of partial sequences of the nuclear GHR gene and morphological characters to derive a phylogeny of species in the family Chrysochloridae.ResultsAlthough not all nodes of the combined analysis have high support values, the overall pattern of relationships obtained from different methods of phylogeny reconstruction allow us to make several recommendations regarding the current taxonomy of golden moles. We elevate Huetia to generic status to include the species leucorhinus and confirm the use of the Linnean binomial Carpitalpa arendsi, which belongs within Amblysominae along with Amblysomus and Neamblysomus. A second group, Chrysochlorinae, includes Chrysochloris, Cryptochloris, Huetia, Eremitalpa, Chrysospalax, and Calcochloris. Bayesian methods make chrysochlorines paraphyletic by placing the root within them, coinciding with root positions favored by a majority of randomly-generated outgroup taxa. Maximum Parsimony (MP) places the root either between chrysochlorines and amblysomines (with Chlorotalpa as sister taxon to amblysomines), or at Chlorotalpa, with the former two groups reconstructed as monophyletic in all optimal MP trees.ConclusionsThe inclusion of additional genetic loci for this clade is important to confirm our taxonomic results and resolve the chrysochlorid root. Nevertheless, our optimal topologies support a division of chrysochlorids into amblysomines and chrysochlorines, with Chlorotalpa intermediate between the two. Furthermore, evolution of the chrysochlorid malleus exhibits homoplasy. The elongate malleus has evolved just once in the Cryptochloris-Chrysochloris group; other changes in shape have occurred at multiple nodes, regardless of how the root is resolved.
The standard karyotypic properties of 60 of the 73 species of bats known to occur in southern Africa, are reviewed. The karyotypes of 23 microchiropteran species are described for the first time; our results on a further 14 species are compared with earlier reports for those taxa. The previously published chromosomal information pertaining to 23 species for which we had no information, are cited. Systematic implications of observed patterns of karyotypic variation are briefly discussed. In particular, we conclude that the taxon Cistugo (currently recognised as a subgenus oiMyotis) should be afforded full generic rank; hypothesise that the karyotypes of the two species - M. (C.) seabrai and M. (C.) lesueuri - in Cistugo are probably ancestral for all vespertilionids; and question the wisdom of redefining the taxonomic limits of the genera Eptesicus and Pipistrellus until molecular data are available to resolve the dilemma posed by conflicting morphological and cytogenetic data suites
The large brown, round, strongly scented seeds of Ceratocaryum argenteum (Restionaceae) emit many volatiles found to be present in herbivore dung. These seeds attract dung beetles that roll and bury them. As the seeds are hard and offer no reward to the dung beetles, this is a remarkable example of deception in plant seed dispersal.
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