EXTRACT FROM THE FOLLOWING THIRD PARTY SOURCE: Written by: GrrlScientist for The Guardian
The Canid family – wolves, coyotes, jackals, foxes, domestic dogs and others – are so familiar to us, and have been intensively studied for so long that you might think that we know almost everything there is to know about them. But a paper published recently in Current Biology belies that assumption. This paper describes the meticulous research conducted by an international team of experts who report a surprising discovery: a new species of wolf.
According to the authors, two golden jackal populations – one in Eurasia and the other in Africa – split more than one million years ago, which is sufficient to formally recognise each as separate species. Furthermore, after exhaustive DNA analyses, the authors were surprised to learn that African golden jackals are more closely related to grey wolves, even though there are no grey wolves in Africa and even though grey wolves and African golden jackals look dramatically different. Adding to the confusion, African golden jackals are strikingly similar in appearance to their more distant relative, the Eurasian golden jackal. This strong physical similarity has long been the source of confusion over these animals’ taxonomy and evolutionary relationships.
As a result of this study, the authors propose that the African golden jackal be renamed as the African golden wolf, Canis anthus.
The evolutionary relationships of canids are poorly understood
The evolutionary relationships of jackals have long been a mess, according to Adam Hartstone-Rose, an associate professor of cell biology and anatomy at the University of South Carolina School of Medicine, who was not part of the study. Traditionally, most taxonomists have recognised three jackal species: the black-backed, side-striped and golden jackals – all of which live in Africa, with the golden jackal also ranging throughout much of Eurasia.
“The three ‘species’ were considered close relatives based mostly on their similar body size and morphology”, explained Professor Hartstone-Rose via email. “The side-striped and black-backed species turn out to have split off of the stem of the large Canis group before the highly derived hunting dogs and dholes.”
Two earlier studies reported that golden jackals found in Africa are more closely related to grey wolves than to the golden jackals found in Eurasia (doi:10.1371/journal.pone.0016385 & doi:10.1371/journal.pone.0042740). These studies inspired Klaus Koepfli, a Research Associate and Visiting Scientist at the Center for Species Survival (CSS), which is part of the Smithsonian Conservation Biology Institute, to investigate more thoroughly.
African and Eurasian golden jackals are genetically distinct
“Consistent with two previous studies also based on mitochondrial sequences, we find that golden jackals from Africa and Eurasia are NOT each other’s closest relative as we would expect if they were the same species”, said Dr Koepfli.
“We found that the African golden jackal lineage split from grey wolves plus coyotes about 1.3 million years ago. The Eurasian golden jackal lineage, however, split about 600,000 years prior to that”, said Dr Koepfli.
Not only does the chromosomal (nuclear) DNA data phylogeny suggest a close relationship between African golden jackals and grey wolves, but it indicates that the Eurasian golden jackal split away from the grey wolf long before grey wolves and coyotes diverged.
“If African and Eurasian golden jackals belonged to the same species, we would expect these two groups to be more closely related (share common ancestry)”, said Dr Koepfli.
But African and Eurasian golden jackals look very similar
Despite their distinct genetic ancestries, African and Eurasian golden jackals look so much alike that most scientists classified them as the same species.
Analyses of morphometric data revealed that despite their genetic distance, the golden jackals have a strong resemblance to each other. But why do these two species look so much alike that they fooled almost everyone for hundreds of years?
“Since the two jackal lineages are not closely related, this morphological similarity may be due to parallel evolution, driven by the ecological circumstances in which these animals live, especially with regards to the competition from other carnivore species”, said Dr Koepfli.
Parallel evolution is the development of a similar trait in related, but distinct, species that share a common ancestor. This differs from convergent evolution, where species with different evolutionary histories independently evolve traits that are similar in form or function (such as wings in flying insects, bats and birds) due to similar ecological demands.
African golden jackals renamed African golden wolves
This painstaking work shines a powerful light on the convoluted relationship between ecology and evolution and reveals how ecology can lead to confusion amongst even the most astute experts when it comes to identifying species. Further, these findings demonstrate why it is critical to analyse living species from all perspectives – anatomic, behavioural, ecological and genetic – in order to truly understand the evolution of those species.
“Within eastern Africa where I do most of my work, all canids (not just golden jackals) are relatively rare in the fossil record. Therefore, this study provides us with an intriguing glimpse of carnivore evolution that we might not otherwise know about”, said vertebrate palaeontologist Margaret Lewis, a Professor of Biology at Stockton University, who was not part of this study.
This research also has important conservation implications. For example, as established here, one widespread species may actually be several cryptic species.
“What if your two new species represented vastly different percentages of the former species? One of the new species could be doing relatively well while the other population is on the verge of extinction”, said Professor Lewis in email.
Currently, golden jackals (Eurasian and African) are listed by the IUCN as of Least Concern, but this assessment was made in 2008, before any of the recent genetic work on this group.
“While they are considered to be fairly common (particularly in Asia), it will be interesting to see if African golden wolves and Eurasian golden jackals will each retain this ranking in the next assessment. Jackals, in general, are declining as traditional land-use practices disappear and are replaced by industrialisation and urbanisation. All jackals and jackal-like animals, not just African golden wolves, play a critical role in the ecology of their respective habitats”, said Professor Lewis.
“Hopefully, this research will raise awareness of the importance of jackals and similar species around the world before it is too late”, said Professor Lewis.
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