AJP Featured Articles

Minerals in the foods and diet of diademed sifakas: Are they nutritional challenges?

Authors: Irwin, Mitchell T., Raharison, Jean-Luc, Chapman, Colin A., Junge, Randall E., Rothman, Jessica M.

Minerals, though needed in small quantities, are critical for survival and reproduction. However, our knowledge of how much of a challenge they pose to wild primates is limited by two knowledge gaps. First, few data exist on mineral content of primate foods (and fewer still for overall dietary intakes). Second, assessing “adequacy” is complicated – recommendations for captive primates and humans are clearly conservative, and absorption efficiency varies across foods and consumers.

We present a comprehensive “mineral profile” for the diademed sifaka, quantifying mineral concentration in foods, and proportional and absolute dietary intakes. For six minerals, mean concentrations in foods were below National Research Council recommendations for captive primates, and concentrations varied across food types (plant part and plant type). Mineral intakes varied seasonally, in a complex way: lean season foods were richer in minerals, but absolute intakes (g/day) were highest in the abundant season, due to the increase in food ingested. Finally, disturbed habitat groups’ diets were richer in five minerals, but this translated into increased intakes only for copper, as these groups ate less food overall.

Simple comparisons with NRC recommendations suggest sifakas might be experiencing deficiencies (especially for Ca, P, and Zn); however, mass-specific intakes (g/day) exceeded human recommendations, and the sifakas don’t show signs of deficiency. More research is needed to quantify mineral consumption and true minimum requirements in wild primates – this will help in understanding the role minerals played in the evolution of dietary strategies, and in formulating captive diets and managing habitats for the future.

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Description of a new species of Hoolock gibbon (Primates: Hylobatidae) based on integrative taxonomy

Authors: Fan, P-F., He, K., Chen, X., Ortiz, A., Zhang, B., Zhao, C., Li, Y-Q., Zhang, H-B., Kimock, C., Wang, W-Z., Groves, C., Turvey, S.T., Roos, C., Helgen, K.M., Jiang, X-L.

Hoolock gibbons (genus Hoolock) occur in the northwestern part of the modern-day gibbon distribution in east India, Bangladesh, Myanmar and southwest China. The genus of hoolock gibbons comprises two previously described living species, the western (Hoolock hoolock) and eastern hoolock (H. leuconedys) gibbons, geographically isolated by the Chindwin River. Based on careful examination of external morphology, craniodental and genetic characteristics of wild animals and museum specimens, we concluded that hoolock gibbons distributed between the Irrawaddy-Nmai Hka Rivers and the Salween River, which are currently assigned to H. leuconedys, are morphologically and genetically distinct from those to the west of the river, and should be recognized as a new species. We named it as Gaoligong hoolock gibbon or skywalker hoolock gibbon (Hoolock tianxing), referring to the unique locomotory mode of gibbons and following an ancient proverb from I Ching. We consider that the new species should be categorized as Endangered under IUCN criteria. The discovery of the new species focuses attention on the need for improved conservation of small apes, many of which are in danger of extinction in southern China and Southeast Asia.

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