Flag for Taxon: Northern Bushbuck (Tragelaphus scriptus)
| Flagger | Content Author | Content | Reason | Flag Created | Resolved by | Resolution |
|---|---|---|---|---|---|---|
| tonyrebelo | Northern Bushbuck (Tragelaphus scriptus) |
What is happening with Tragelaphus sylvaticus. There is now a Redlist assessment for it for southern Africa, but iNat still regards it as a subspecies of an unrelated species ... Has the promised Nuclear DNA not been done? |
Dec. 31, 2017 10:02:03 +0000 | jakob |
iNat's mammal taxonomy currently follows the IUCN Red List, which still has it as a single species http://www.iucnredlist.org/details/22051 |
Comments
Not premature. Just not adequately verified.
Just checking back in on this. IUCN still treats Tragelaphus scriptus as sensu lato but our reference (MDD) carves off Tragelaphus sylvaticus as a distinct species. Any reason not to follow MDD and make this split?
I would be happy to follow MDD. I have not however seen anything in the literature to support/disagree/dispute the suggestion as separate.
which ssp would go with Tragelaphus sylvaticus?
Tragelaphus scriptus ssp. bor 65
Tragelaphus scriptus ssp. fasciatus 3
Tragelaphus scriptus ssp. meneliki 26
Tragelaphus scriptus ssp. ornatus 146
Tragelaphus scriptus ssp. scriptus 0
Tragelaphus scriptus ssp. sylvaticus 1,757
I dont know.
Wiki::
In 2011, Groves and Grubb advocated recognising eight species of bushbuck: T. scriptus (Pallas, 1766); T. phaleratus (Hamilton Smith, 1827); T. bor Heuglin, 1877; T. decula (Rüppell, 1835); T. meneliki Neumann, 1902; T. fasciatus Pocock, 1900; T. ornatus Pocock, 1900; and T. sylvaticus (Sparrman, 1780), grouped in a northern and southern 'group'.[4] The Ethiopian endemic species known as Menelik's bushbuck or decula was classified as a scriptus group species as opposed to Woodley. In the case of Tragelaphus, these 'species' would be based mostly on geography and pelage as opposed to genetics.[5] These proposals are controversial.[6]
In 2018, Hassanin et al. published a molecular phylogenetic study that provided support for the scriptus and sylvaticus clades, with a divergence time of at least 2 million years, albeit with considerable genetic diversity within each of these groups.[7]
So that is no use
Moodley, Y.; et al. (September 2009). "Analysis of mitochondrial DNA data reveals non-monophyly in the bushbuck (Tragelaphus scriptus) complex". Mammalian Biology. 74 (5): 418–422. doi:10.1016/j.mambio.2008.05.003.
scriptus clade
T. scriptus “bor”
T. scriptus “scriptus”
sylvaticus clade
T. sylvaticus“ornatus”
T. sylvaticus“sylvaticus”
T. sylvaticus “meneliki”
T. sylvaticus “fasciatus”
But I cannot find any maps or confirmation of these.
Maybe @milewski wants to chime in.
In my view, there are two spp., sylvaticus and scriptus, more or less as per Groves and Grubb (2011).
If memory serves, ornatus is a subspecies of scriptus (which would be consistent with colouration), while meneliki would be a subspecies of sylvaticus.
The trouble is that the two spp. have almost certainly interbred along a frontier ranging from the Okavango to South Sudan.
Some of the best (anecdotal) evidence for a species-distinction comes from Gorongosa in south-central Mozambique, where two recognisably distinct forms occur according to habitat (K L Tinley, probably mentioned in his PhD thesis, now a book in its own right), within savannas similar to those of Kruger National Park. These two types seem to function as 'ecotypes' within this area, but may reflect hybridisation in which a predominance of scriptus-type genetic influence seeks out riparian forest, while a predominance of sylvaticus-type genetic influence seeks out bush-clumps in savanna, at a mosaic-scale of tens of metres, not kilometres. Such differentiation is hard to explain without invoking different spp. of bushbucks, not so?
scriptus-type at Gorongosa: https://www.inaturalist.org/observations/121290018
sylvaticus-type at Gorongosa: https://www.inaturalist.org/observations/120788539
Any chance of checking your memory?
All the work I have looked at puts T. sylvaticus“ornatus” into sylvaticus group.
They may well be both and different at Gorongosa, but they are both sylvaticus according to the DNA.
it is in the north where the rift valley separates sylvaticus (meneliki & asciatus) from scriptus (bor & scriptus).
It is not just a colouration thing: both species have odopted the same habitat, colouration and morphology, to the extent that they cannot easily be told apart (as species: the subspecies have pattern differences) without DNA.
Sorry, I don't have any further information to hand at the moment.
Of course it is possible that ornatus is just a striped subspecies of sylvaticus. However, this would be odd, given that sylvaticus all the way from Agulhas to Ethiopia seems more or less similarly stripeless. Apart from ornatus, the variation within sylvaticus is mainly in darkness and possibly thickness of pelage.
In northwestern Angola, where the ssp. is thought to be ornatus, the appearance (https://www.inaturalist.org/observations/9654728) is so similar to scriptus that it would remarkable indeed if this was merely a case of a subspecies of sylvaticus converging with scriptus.
So, I infer that scriptus has indeed penetrated south of the equatorial bloc of rainforest, which means a barrier-free intergradation through to Zambia (where the appearance is typical for ornatus, https://www.alamy.com/stock-photo-bush-buck-in-kafue-national-park-zambia-africa-48247688.html).
In other words, even if ornatus of Zambia is a subspecies of sylvaticus, 'ornatus' of northwestern Angola is probably a subspecies of scriptus, leaving us with the likelihood of broad intergradation across Angola - as opposed to any clearer-cut distinction around the Great Rift in East Africa.
see https://www.inaturalist.org/taxa/42341-Tragelaphus-scriptus
use map tab and switch on the GBIF data.
It is quite possible that the Angolan forms are from the west, and nothing to do with the southern-eastern forms. I dont know which subspecies the Angolan populations are ascribed to. With the understanding that sampling is likely uneven, there does appear to be a clear gap between the Angolan and Caprivi- Zambian populations.
If the DNA is correct, there is little chance of hybridization: scriptus and sylvaticus are totally unrelated - greater genetic divergence between them than to Kudu or Eland.
In The mammals of Angola (in the book edited by Huntley et al,, available in full online), the authors do ascribe the form in northwestern Angola to ornatus, while reminding readers of the taxonomic problems. Furthermore, their account does not hint at any gap in occurrence between northwestern Angola and southeastern Angola. It is safe to say that bushbucks are widespread in that country.
So, if the spp. really are distinct and unlikely to interbreed, then the only remaining possibility would be a sharp border between them somewhere in Angola. This is of course possible, but if so it is unlikely to correspond to any geographical barrier.
Yes, it makes sense that the southern African populations are all the same, and that the barrier is probably to the north. But Bushbuck are one of the species that occur along the west coast as well, so somewhere north of Angola the two species must meet?
The obvious barrier would be the Congo River.(https://upload.wikimedia.org/wikipedia/commons/f/f1/Congobasinmap.png). It does seem plausible that sylvaticus is the species south of the mouth of this river, and east of the African Rift. Bushbucks swim well, but this is indeed a major river.
One way to test this would be to look in detail at the markings in northwestern Angola, compared to e.g. Cameroon or Ghana.
If it is indeed the case that the form in northwestern Angola belongs to sylvaticus, then it needs a new subspecies-name, because it is more strongly striped and spotted than ornatus of Zambia.
It would be remarkable enough that this unnamed subspecies (let us call it cuanzensis) has converged so strongly with species strictus. But there is no chance that the convergence has produced exact replication of the pattern.
If a study shows that there is exact correspondence in pattern between subspecies cuanzensis and the subspecies of species strictus that occurs north of the mouth of the Congo River, then I would assume that cuanzensis is actually part of species strictus - regardless of what any genetic study finds. This would be based on the principles of scientific investigation, which should not favour abstract and inferential evidence over direct and observable evidence.
My current estimation of probabilities:
The chance that species scriptus and species sylvaticus really are so genetically different that they do not interbreed: 5%
The chance that these two species have intergraded across an extremely wide area, from northwestern Angola to Mozambique and Tanzania: >50%
The chance that whichever genetic study attempts to resolve this problem will be contradicted by a subsequent, equally valid-looking study within a few years: >50%.
I have before me a copy of 'The Mammals of Angola, Africa' (1941) by J E Hill and T D Carter. Bulletin of the American Musem of Natural History, vol. LXXVIII, Art. 1, pp. 1-211.
On page 161, the authors state that the form of bushbuck in Angola is Tragelaphus scriptus ornatus Pocock, 1900, the type locality of which is 'Linyante, Chobe River, Eastern Caprivi, South West Africa'.
They state:
"Five specimens of bushbuck were secured by the Vernay Angola Expedition: Chitau, 4 (native skins only); Mombolo (Namba), 1 (skull only). This antelope has been recorded from Caconda (Bocage, 1890); near Humpata (Sokolowsky, 1903); Caporolo River (Statham, 1922); Hanha (Themido, 1931). One specimen from Chitau shows a weak upper longitudinal stripe from the shoulder, the others agree closely with Pocock's original description. The skull is injured and there are no measurements for the specimens."
Chitau is in Bie province, central Angola (https://www.nationsonline.org/oneworld/map/angola_map2.htm).
Mombolo is in west-central Angola, northeast of Benguela.
This indicates that there is indeed a difference between a) the extremely striped and spotted form recorded from northwestern Angola in iNaturalist and b) the form mentioned in Hill and Carter (1941) from central and west-central Angola, which agrees with ornatus from the Caprivi Strip.
This in turn does support the notion that ornatus could be a subspecies of sylvaticus, extending all the way from the Caprivi Strip to the central coast of Angola, then abruptly giving way to 'cuanzensis', which I surmise to be a subspecies of scriptus that occurs south of the Congo River.
What this would mean, in turn, is that there are currently no observations in iNaturalist of either subspecies ornatus or species sylvaticus in Angola.
Perhaps you should revise your odds:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6476403/
The boundary is indeed the Congo River, but only in the far west, it then becomes the Kasai River well south of the main course. How this boundary was drawn with the given samples I dont know.
This paper confirms:
scriptus clade
T. scriptus “bor”
T. scriptus “scriptus”
(and dodingae, decula, phaleratus)
sylvaticus clade
T. sylvaticus“ornatus”
T. sylvaticus“sylvaticus”
T. sylvaticus “meneliki”
T. sylvaticus “fasciatus"
(and delemerei, barkeri, dianae, dama, massaicus, roualeyni)
MDD's maps (available here: https://mol.org/datasets/ec694c34-bddd-4111-ba99-926a5f7866e8) split this like this. Does that seem reasonable? (T. sylvaticus dark, T. scriptus light)
Yes, I am coming around to the view that ornatus is a subspecies of sylvaticus, and that there is a fairly abrupt border, south of Luanda (capital city of Angola) between Tragelaphus sylvaticus ornatus and Tragelaphus scriptus (what I call ssp. 'cuanzensis').
This reduces my estimated probability of a vast intergradation between the two species, in south-central Africa, to <25%.
Here is the map: https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=6476403_peerj-07-6476-g001.jpg
so the MDD map is plausible.
I would correct this map in at least one respect.
The species-boundary should be shifted southwards in western Angola, to considerably south of the capital city of Luanda. This is based on the following two lines of evidence, each of which is strong. Firstly, according to Hill and Carter (1941), the form occurring in west-central Angola is indeed ornatus (which we take to be a ssp. of sylvaticus). Secondly, the form documented in iNaturalist from Parque Nacional da Quicama, just south of Luanda, is obviously species scriptus.
So, the real boundary would correspond to the boundary between Bengo province and Cuanza Sul province (https://www.burningcompass.com/countries/angola/angola-political-map-hd.html).
This means a southward shift of the boundary on the west coast of Angola, of about 300 km - eliminating the little 'tongue' of brown on the map.
What is incorrect in the map you just linked:
The species-boundary is shown as corresponding to the Congo River. This was a reasonable guess. However, as shown by the photographs from south of Luanda in iNaturalist, scriptus has crossed the Congo River. So, the boundary should be shifted southwards by about 500 km.
What seems to be emerging, overall:
There are at least two big surprises in the phylogeny of bushbucks.
Firstly, there is a 'hard' boundary between the northwestern species (scriptus) and the southeastern species (sylvaticus), between Luanda and Benguela in Angola, without any geographical barrier whatsoever.
Secondly, there is another defiance of geography in that species scriptus has not only usurped the habitat of species sylvaticus in northern Ethiopia, but has also converged with the latter in colouration there.
ok - there are no observations from that part of Angola so it shouldn't effect the split. Those ranges are just a guide. I'll make this split and swap 4 of the 6 ssp over with T. sylvaticus :
T. scriptus ornatus -> T. sylvaticus ornatus
T. scriptus sylvaticus -> T. sylvaticus sylvaticus
T. scriptus meneliki -> T. sylvaticus meneliki
T. scriptus fasciatus -> T. sylvaticus fasciatus
I have yet to look into the situation in Ethiopia. However, as I understand it, the form northwest of the Rift is decula, while the form southeast of the Rift is meneliki. If so, and if the northwestern form actually belongs to species scriptus (as shown by genetic studies), then the observations in iNaturalist in northern Ethiopia should be renamed as Tragelaphus scriptus decula.
OK committed
https://www.inaturalist.org/taxon_changes/118254
There are about 100 obs that got rolled back to subgenus. If you can help roll them forward by adding new IDs here that would be super helpful, thanks all!:
https://www.inaturalist.org/observations/identify?reviewed=any&quality_grade=needs_id%2Cresearch&verifiable=any&id=143825096%2C143673464%2C142943404%2C142212791%2C139951470%2C94990044%2C98814261%2C138438055%2C133200392%2C135845192%2C134277628%2C131684612%2C131666427%2C130087191%2C128556246%2C126707399%2C126707216%2C124510652%2C124362234%2C123271075%2C123271146%2C123248053%2C119924226%2C117860703%2C42385130%2C116873613%2C111626181%2C42385121%2C106521914%2C106456820%2C105865852%2C105801216%2C105803109%2C32339053%2C104531067%2C104055552%2C4651403%2C103898109%2C100417064%2C98790993%2C92814316%2C92706297%2C90526460%2C89923119%2C87569204%2C84669207%2C82347838%2C72619967%2C8277087%2C8278712%2C8326579%2C8706391%2C8706667%2C8707277%2C17912137%2C70602485%2C69258709%2C68932744%2C67659440%2C67458001%2C67457338%2C67260756%2C65080102%2C64301135%2C62739720%2C58937840%2C58937839%2C58225579%2C57167411%2C52034430%2C53942980%2C54749354%2C54749351%2C53813344%2C53600698%2C52410501%2C52005375%2C46545290%2C47522767%2C47377544%2C46344982%2C46129496%2C39482664%2C45502899%2C45502906%2C45720292%2C45075220%2C45089707%2C45081258%2C38565510%2C39239655%2C40578964%2C41618768%2C41618939%2C41765896%2C41765926%2C41833634%2C42466965%2C44748279%2C42741742%2C42570426%2C42570690%2C42383634%2C42253809%2C42253816%2C42253829%2C42258448%2C41286561%2C40768083%2C9635706%2C9654728%2C40303463
Ah thanks: I just assumed all would be identified to subspecies and would thus automicatically transfer, but I guess only a few identifiers actually work at subspecies level.
Will do.
Ah good: none in southern Africa.
Re Angola - Luanda:
there is a 'hard' boundary between the northwestern species (scriptus) and the southeastern species (sylvaticus), between Luanda and Benguela in Angola, without any geographical barrier whatsoever.
The DNA sampling from Lifune, Angola - is north of Luanda and is sylvaticus ornatus - Angolan Bushbuck
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6476403/
I have identified them all as subsp. ornatus, but because of the way iNaturalist mistreats subspecies identifications, they are still all in the subgenus.
Seems to be nothing published since the mtDNA study of Moodley 2009 so I guess not. Split seems to be premature without further studies.