Evidence of constant diversification punctuated by a mass extinction in the African cycads

The recent evidence that extant cycads are not living fossils triggered a renewed search for a better understanding of their evolutionary history. In this study, we investigated the evolutionary diversification history of the genus Encephalartos, a monophyletic cycad endemic to Africa. We found an antisigmoidal pattern with a plateau and punctual explosive radiation. This pattern is typical of a constant radiation with mass extinction. The rate shift that we found may therefore be a result of a rapid recolonization of niches that have been emptied owing to mass extinction. Because the explosive radiation occurred during the transition Pliocene–Pleistocene, we argued that the processes might have been climatically mediated.     

New discoveries of cycads and advancement of conservation of cycads in China

From 1997 to 1999Cycas debaoensis Y. C. Zhong & C. J. Chen andC. changjiangensis N. Liu were described from South China. The wild populations ofCycas szechuanensis were discovered in Fujian.Cycas guizhouensis K. M. Lan & R. F. Zou at the higher elevations andC. segmentifida D. Y. Wang & C. Y. Deng at the lower elevations along the Nanpanjiang River should be good species, which were treated by Chen and Wang (1995) and Chen and Stevenson (1999) as synonyms forC. szechuanensis. However, 11 other new species have been reduced by Chen and Stevenson (1999) and the present authors. They areC. longlinensis Huang T. Chang & Y. C. Zhong,C. xilinensis Huang T. Chang & Y. C. Zhong, C.multifida Huang T. Chang & Y. C. Zhong, C.longiconifera Huang T. Chang & Y. C. Zhong, andC. acuminatissima Huang T. Chang & Y. C. Zhong, all treated as synonyms ofC. segmentifida. Cycas spiniformis J. Y. Liang,C. longisporophylla F. N. Wei,C. septermsperma Huang T. Chang & H. X. Zhang,C. brevipinnata Huang T. Chang et al. should be synonyms forC. exseminifera F. N. Wei.Cycas miquelii Warb, andEpicycas miquelii (Warb.) de Laub, should be the synonyms forC revoluta because their “stype” specimens are somewhat likeC. revoluta. The Honghe Nature Cycad Reserve forCycas multipinnata andC. hongheensis was recently established in Yunnan. The Debao Cycad Reserve will be established soon. However, most existing cycad reserves in China have not been so successful because of shortages of funding and poor management. In ex situ conservation the Qingxiushan Cycad Garden in Nanning, Guangxi, was established. Cycad nurseries have begun to appear in some villages in South China.     

Ethical considerations for clinical photography in the global South

Clinical photography is an important tool for teaching practitioners and field workers about the clinical manifestations of famine and undernutrition, particularly with respect to the Global South. Current international guidelines for clinical photography are not consistently applied or enforced, which has led to violations of privacy and rights, particularly for patients and victims of disaster in the Global South. Combining existing clinical photography guidelines from the North with ongoing clinical ethics debates in the South, this paper explores approaches to establishing photography guidelines throughout the world that will be sensitive to the privacy and dignities of all patients and victims of emergencies.     

South African rock art

The total number of rock art sites in South Africa certainly is in excess of 30,000. Collectively, they include well over a million images. However, fewer than 10,000 sites are listed on official databases. One reason for the lack of documentation is the high cost of establishing and maintaining recording programs. There is also a low level of public interest in rock art because both the art and the history of indigenous peoples have been neglected in school and university curricula. Matters are improving: At least one postgraduate university course dedicated to rock art will be offered at the University of the Witwatersrand beginning in 1999. Moreover, the gradual inclusion of cultural resources in heritage conservation and management programs is continuing. The significance of the oversight in the past is magnified if we consider the fragility of the art and the potential wealth of information it holds for understanding the evolution of South African society over the past 30,000 years. Rock art is an irreplaceable historical archive of extraordinary value. Although no one would dispute that this art must survive intact into the next millennium, research into its meaning is equally important if we are to convince the public that the art is worth saving. It is in this latter field that South African researchers have made a significant contribution to rock art studies in the past three decades.