Can morphotaxa be assessed with photographs? Estimating the accuracy of two-dimensional cranial geometric morphometrics for the study of threatened populations of African monkeys
By Andrea Cardini, Yvonne de Jong and Tom Butynski
Abstract: The classification of most mammalian orders and families is under debate and the number of species is likely greater than currently recognized. Improving taxonomic knowledge is crucial, as biodiversity is in rapid decline. Morphology is a source of taxonomic knowledge, and geometric morphometrics applied to two dimensional (2D) photographs of anatomical structures is commonly employed for quantifying differences within and among lineages. Photographs are informative, easy to obtain, and low cost. 2D analyses, however, introduce a large source of measurement error when applied to crania and other highly three dimensional (3D) structures. To explore the potential of 2D analyses for assessing taxonomic diversity, we use patas monkeys (Erythrocebus), a genus of large, semi-terrestrial, African guenons, as a case study. By applying a range of tests to compare ventral views of adult crania measured both in 2D and 3D, we show that, despite inaccuracies accounting for up to one-fourth of individual shape differences, results in 2D almost perfectly mirror those in 3D. This apparent paradox might be explained by the small strength of covariation in the component of shape variance related to measurement error. A rigorous standardization of photographic settings and the choice of almost coplanar landmarks are likely to further improve the correspondence of 2D to 3D shapes. 2D geometric morphometrics is, thus, appropriate for taxonomic comparisons of patas ventral crania. Although it is too early to generalize, our results corroborate similar findings from previous research in mammals, and suggest that 2D shape analyses are an effective heuristic tool for morphological investigation of small differences.
Thomas M. Butynski & Yvonne A. de Jong (2021). Sympatry between desert warthog Phacochoerus aethiopicus and common warthog Phacochoerus africanus in Kenya, with particular reference to Laikipia County. Suiform Soundings 20(1): 33-44
Abstract
Desert warthog Phacochoerus aethiopicus delamerei and common warthog Phacochoerus africanus are widespread and locally common in the Horn of Africa and Kenya, east of the Eastern Rift Valley. It is of particular interest that these two taxa, the only two extant species in the genus Phacochoerus, occur in sympatry in some regions. Within Kenya, sympatry is known for the northern coast, Tsavo East National Park, Tsavo West National Park, and Meru National Park. This article presents information on a fifth region of sympatry, Laikipia County, central Kenya. Individuals that we judged to be atypical for either desert warthog or common warthog were encountered in Laikipia. New information on the distribution, abundance, population structure, ecology, and behaviour of desert warthog in Laikipia is presented. Laikipia offers considerable opportunity for comparative research on the morphology, molecular biology, ecology, and behaviour of desert warthog and common warthog.
Young adult male desert warthog Phacochoerus aethiopicus, Suyian Ranch, northern Laikipia County, central Kenya. Photo: Yvonne de Jong and Tom Butynski.
The charismatic, semi-terrestrial, southern patas monkey Erythrocebus baumstarki, is probably now restricted in the protected savannas of the western Serengeti (central northern Tanzania). It seems that, at present, fewer than 200 individuals occupy about 15% (9,700 km²) of their early 20th century geographic range. This large, slender, long-limbed, primate once occurred in the acacia woodlands near Mount Kilimanjaro and in southern Kenya but was extirpated from these areas prior to 2016 due to factors related to the rapidly increasing human population. The main threats are the degradation, loss, and fragmentation of natural habitats, and competition with people and livestock for habitat and water. Poaching and domestic dogs are also threats. As a result, this shy and secretive monkey is listed as ‘Critically Endangered’ on the IUCN Red List of Threatened Species [Website: https://www.iucnredlist.org/species/92252436/92252442].
In the absence of focused conservation actions, it appears that the southern patas monkey will be among the first three primate extinctions recorded for continental Africa during the past century. Miss Waldron’s red colobus Piliocolobus waldroni of southern Ghana and southeastern Côte d’Ivoire was last reliably recorded in 1978, while the Mount Kenya potto Perodicticus ibeanus stockleyi is only known from a museum specimen collected in 1938.
In our recent publication (De Jong, Y.A. & Butynski, T.M. 2021. Is the Southern Patas Monkey Erythrocebus baumstarki Africa’s Next Primate Extinction? Reassessing Taxonomy, Distribution, Abundance, and Conservation. American Journal of Primatology,e23316) we assess the historic geographic distribution of the southern patas monkey and give evidence for its former occurrence in Kenya. We present estimates of the current distribution and population size, review the threats, and express our concern for its continued survival. We conclude with suggestions for conservation actions, including research. The objective of this article is to bring attention to the plight of this poorly known species, thereby promoting its long-term conservation.
Dedan K. Ngatia, Paul W. Webala, Mugo J. Mware, Thomas M. Butynski, Yvonne A. de Jong, Adam W. Ferguson (2021). African Journal of Ecology. DOI: 10.1111/aje.12830
Abstract: The paucity of studies on Egyptian mongoose Herpestes ichneumon (Linnaeus, 1758) in Africa highlights the need for baseline information on the geographic range of this species as well as factors that may determine its distribution. This study presents eight novel locality records of H. ichneumon in Laikipia County, central Kenya, addresses questions on the species’ distribution in Africa, and predicts environmental (climatic) suitability across its range. From a total of 4,822 H. ichneumon occurrence records, we used 4,432 georeferenced records to generate distribution maps, conduct ecological niche modelling, and identify environmental limits for this species across its range with a focus on Africa. 20% of all records originate from continental Africa, including 121 records for Kenya. Despite extensive field research and predicted habitat suitability, H. ichneumon has not been previously reported in Laikipia County. Our niche models, however, predicted parts of Laikipia to be environmentally suitable for H. ichneumon. Similarly, our new distribution maps show extended geographic ranges both in Laikipia and Kenya as compared to the 2016 IUCN map. The eight Laikipia records underscore the limited knowledge for this species, its distribution, and its environmental requirements in Africa.
