August 06, 2018

Geographic range, taxonomy, and conservation of the Mount Kilimanjaro guereza colobus monkey (Primates: Cercopithecidae: Colobus)

The Mount Kilimanjaro guereza colobus monkey is endemic to northern Tanzania and southern Kenya, occurring on and near Mount Kilimanjaro/Mount Meru. Currently referred to as “Colobus guereza caudatus Thomas 1885”, this monkey is geographically very isolated, and phenotypically distinct from all other taxa of guereza monkeys. As such, application of the “Phylogenetic Species Concept” resurrects the Mount Kilimanjaro guereza to specific rank as Colobus caudatus. The geographic range of C. caudatus is small (ca. 4030 km2) and in decline, as is the number of individuals and area of habitat. Colobus caudatus qualifies as an IUCN Red List globally “Endangered” species, as a nationally “Endangered” species in Tanzania, and as a nationally “Critically Endangered” species in Kenya. Colobus caudatus is Kenya’s most threatened species of primate. Recommendations for research and conservation actions are provided.

Full publication on: and,82059,0,2.html

Butynski & De Jong (2018) Geographic range, taxonomy, and conservation of the Mount Kilimanjaro guereza colobus monkey (Primates: Cercopithecidae: Colobus). Hystrix.

Posted on August 06, 2018 03:16 PM by dejong dejong | 4 comments | Leave a comment

July 06, 2018

Pocket Identification Guide of the Primates of East Africa

Yvonne A. de Jong & Thomas M. Butynski
Illustrations & Design Stephen Nash

70 taxa • 32 distribution maps • 73 drawings
More information on:

Posted on July 06, 2018 02:56 PM by dejong dejong | 0 comments | Leave a comment

August 27, 2017

Distribution of Madoqua in East Africa

New publication:

Distributions in Uganda, Kenya, and north Tanzania of members of the Günther’s dik-dik Madoqua (guentheri) and Kirk’s dik-dik M. (kirkii) species groups, regions of sympatry, records of aberrant-coloured individuals, and comment on the validity of Hodson’s dik-dik M. (g.) hodsoni

De Jong, Y.A. & Butynski, T.M. 2017. Gnusletter 34: 11-20

Abstract: This paper summarises what is known about the distributions, in Uganda, Kenya, and north Tanzania, of members of the Günther’s dik-dik Madoqua (guentheri) and Kirk’s dik-dik Madoqua (kirkii) species groups. This includes regions of sympatry that extend from near the Indian Ocean in south Somalia and Kenya westward through central Kenya to central east Uganda. Three traits for distinguishing Günther’s dik-dik M. (g.) guentheri and Smith’s dik-dik M. (g.) smithii from Kirk’s dik-dik M. (k.) kirkii and Cavendish’s dik-dik M. (k.) cavendishi in the field are provided. More than a dozen records (some supported by photographs) of aberrant-coloured (i.e., greyish and all-white) M. (guentheri) are presented. The question of whether Hodson’s dik-dik M. (g.) hodsoni is a valid species/subspecies is reviewed as this taxon appears to be based on several aberrant greyish individuals.

Full article is found on:

Posted on August 27, 2017 05:08 AM by dejong dejong | 0 comments | Leave a comment

May 12, 2017

The Mount Kenya Potto is a Subspecies of the Eastern Potto Perodicticus ibeanus

Publication by: Thomas M. Butynski & Yvonne A. de Jong, Eastern Africa Primate Diversity and Conservation Program, Lolldaiga Hills Research Programme, Nanyuki, Kenya
In: Primate Conservation 2017 (31):

The Mount Kenya potto is currently considered a subspecies of the western potto (i.e., Perodicticus potto stockleyi). We argue that the Mount Kenya potto is a subspecies of the eastern potto (i.e., Perodicticus ibeanus stockleyi). This subspecies has not been observed alive for 79 years, and is assessed on the 2017 Red List as Critically Endangered (Possibly Extinct). We indicate priority field sites in which to search for P. i. stockleyi.

Posted on May 12, 2017 08:59 AM by dejong dejong | 3 comments | Leave a comment

October 20, 2016

Photographic Maps for the Primates, Warthogs and Hyraxes of Africa

The design and implementation of effective conservation measures for primates, warthogs and hyraxes requires an efficient, low cost, and accessible resource for the identification of species and subspecies. Although photographs cannot replace an adequate museum collection as a resource for assessing species variation, geotagged photographs are a relatively fast, inexpensive, convenient, and unobtrusive means for detecting and assessing phenotypic variation within a species/subspecies over large areas. The use of photographs to document phenotypic characters will become increasingly important as the collection of specimens for hands-on assessments becomes ever more difficult.

Our 14 newly up-graded on-line photographic maps (or ‘PhotoMaps’;, with over 2400 images (September 2016) of African primates, warthogs and hyraxes, together with the latest distribution maps, provide insight into each taxon’s phenotypic characters, diversity and biogeography. These ‘living’ collections of geotagged images are a practical tool for documenting and discussing diversity, taxonomy, biogeography, distribution and conservation status and, therefore, for planning actions for conservation.

PhotoMaps are useful to those who want to:
• identify species/subspecies;
• know which species/subspecies occur in which areas;
• obtain species/subspecies photographs;
• confirm species distribution;
• describe variation within a species/subspecies, especially as it relates to geographic distribution.

If you have photographs of African primates, warthogs or hyraxes from the less documented areas of Africa (i.e., gaps on the PhotoMaps), please consider contributing them to the PhotoMaps. The photographers name is attached to each photograph. Anyone wishing to use a PhotoMap photograph must obtain both permission and the photograph from the photographer.

Send your photographs, and the coordinates and/or place name of the site where the photographs were obtained, to or send me the link to the iNat record.

We thank Arnoud de Jong for his technical expertise and great help with the PhotoMaps.

Posted on October 20, 2016 05:11 PM by dejong dejong | 2 comments | Leave a comment

December 01, 2015

Request for baboon images

To expand our 'Baboon PhotoMap' (more information on we are looking for baboon photographs from southern Tanzania, northern Mozambique, Zambia, Malawi and southeast DRC. If you happen to have baboon images from this region which you are willing to share, please post them in the 'Primates of Eastern Africa' Project or send a copy to together with your full name (so that we can acknowledge you accordingly) and the coordinates or a detailed locality description of your record.

Thank you very much for your help! Yvonne​

​​Yvonne A. de Jong, PhD
Eastern Africa Primate Diversity and Conservation Program
P.O. Box 149, Nanyuki 10400, Kenya,

Posted on December 01, 2015 05:01 PM by dejong dejong | 2 comments | Leave a comment

November 12, 2015

Vocal Profiles of the Galagidae

By Yvonne de Jong, Simon Bearder, Tom Butynski & Andy Perkin,

Bushbabies or galagos make structurally distinct calls in three main contexts: 1) social cohesion; 2) anxiety and alarm; 3) agonistic contact. Up to 25 calls have been identified in the best-studied species, but many of these are rarely heard or relatively quiet, making them difficult to record. For this reason we make a distinction between the vocal repertoire (all the calls made by each species) and the vocal profile (a set of the most common structurally distinct call types). Species can be distinguished by a unique vocal profile, with at least one or two call types that are not given by other species. One call type, the vocal advertisement (VA), is given both by males and females to attract companions and to repel rivals. This call is particularly loud and useful in distinguishing species and is listed first in each profile.

To listen to the vocal profiles please go to:

Posted on November 12, 2015 04:44 AM by dejong dejong | 2 comments | Leave a comment

June 30, 2015

Distribution and Conservation Status of the Mount Kilimanjaro Guereza

New Publication by T.M. Butynski & Y.A. de Jong, Primate Conservation 29.

'Distribution and Conservation Status of the Mount Kilimanjaro Guereza (Colobus guereza caudatus) Thomas, 1885'

Thank you Alyssa Semerdjian, Martin Grimm and John Ratzlaff for the valuable records you shared in the ´Primates of Eastern Africa´ project!

Read the article on!

Posted on June 30, 2015 06:29 AM by dejong dejong | 0 comments | Leave a comment