Editing Reindeer (section)

== Taxonomy ==

=== Naming and research on museum collections ===
[[Carl Linnaeus]] in 1758 named the Eurasian tundra species ''Cervus tarandus'', the genus ''Rangifer'' being credited to Smith, 1827.<ref name="ITZN-1958" />

''Rangifer'' has had a convoluted history because of the similarity in antler architecture (brow tines asymmetrical and often palmate, bez tines, a back tine sometimes branched, and branched at the distal end, often palmate).{{Citation needed|date=September 2024}} Because of individual variability, early taxonomists were unable to discern consistent patterns among populations, nor could they, examining collections in Europe, appreciate the difference in habitats and the differing function they imposed on antler architecture.{{Citation needed|date=September 2024}} Comparative morphometrics, the measurement of skulls, is often seen as more objective than description of differences of color or antler patterns, but actually confounds genetic variance with epistatic and statistical variance as well as compounded environment-based variance.<ref name="Geist-2007" />

For example, woodland caribou males, rutting in boreal forest where only a few females can be found, collect harems and defend them against other males, for which they have short, straight, strong, much-branched antlers, beams flattened in cross-section, designed for combat — and not too large, so as not to impede them in forested winter ranges.{{Citation needed|date=September 2024}}

By contrast, modern tundra caribou (see [[Reindeer#Evolution|Evolution]] above) have synchronized calving as a predator-avoidance strategy, which requires large rutting aggregations.{{Citation needed|date=September 2024}} Males cannot defend a harem because, while he was busy fighting, they would disappear into the mass of the herd. Males therefore tend individual females; their fights are infrequent and brief.{{Citation needed|date=September 2024}} Their antlers are thin, beams round in cross-section, sweep back and then forward with a cluster of branches at the top; these are designed more for visual stimulation of the females.{{Citation needed|date=September 2024}} Their bez tines are set low, just above the brow tine, which is vertically flattened to protect the eyes while the buck "threshes" low brush, a courtship display.<ref>{{Cite journal |last=Pruitt Jr. |first=William |date=1966 |title=The Function of the Brow-Tine in Caribou Antlers |journal=Arctic |volume=19 |issue=2 |pages=110–113|doi=10.14430/arctic3419 |doi-access=free }}</ref> The low bez tines help the wide flat brow tines dig craters in the hard-packed tundra snow for forage, for which reason brow tines are often called "shovels" in North America and "ice tines" in Europe. The differences in antler architecture reflect fundamental differences in ecology and behavior, and in turn deep divisions in ancestry that were not apparent to the early taxonomists.

Similarly, working on museum collections where skins were often faded and in poor states of preservation, early taxonomists could not readily perceive differences in coat patterns that are consistent within a subspecies, but variable among them. Geist calls these "nuptial" characteristics: sexually selected characters that are highly conserved and diagnostic among subspecies.<ref name="Geist1998" /><ref name="Geist-2007" />

=== Biological exploration expeditions ===
Towards the end of the 19th century, national museums began sending out biological exploration expeditions and collections accumulated. Taxonomists, usually working for the museums, began naming subspecies more rigorously, based on statistical differences in detailed cranial, dental and skeletal measurements than antlers and pelage, supplemented by better knowledge of differences in ecology and behavior. From 1898 to 1937, [[mammalogist]]s named 12 new species (other than barren-ground and woodland, which had been named earlier) of caribou in Canada and Alaska, and three new species and nine new subspecies in Eurasia, each properly described according to the evolving rules of zoological nomenclature, with type localities designated and type specimens deposited in museums (see table in [[Reindeer#Species and subspecies|Species and subspecies]] below).<ref name="Harding-2022" /><ref name="Harding-2022-2">{{Cite web |last=Harding |first=Lee E. |date=2022a |title=Synonymy |url=https://zookeys.pensoft.net/article/80233/download/suppl/31/}} Supplementary file 1 for {{harvp|Harding|2022}}.</ref>

=== Reclassification ===
In the mid-20th century, as definitions of "species" evolved,{{How|date=September 2024}} mammalogists in Europe<ref>{{Cite book |last=Ellerman |first=J. E. |title=Checklist of Palaearctic and Indian mammals, 1758 to 1946 |publisher=British Natural History Museum |year=1951 |location=London, U.K. |pages=1–810}}</ref> and North America<ref name="Banfield-1961">{{Cite book |last=Banfield |first=Alexander William Francis |title=A Revision of the Reindeer and Caribou, Genus Rangifer |publisher=National Museum of Canada Bulletin 177 Biological Series No. 66 |year=1961 |location=Ottawa, Ontario |pages=1–187}}</ref> made all ''Rangifer'' species conspecific with ''R. tarandus'', and synonymized most of the subspecies. [[Alexander William Francis Banfield]]'s often-cited ''A Revision of the Reindeer and Caribou, Genus Rangifer'' (1961),<ref name="Banfield_1961">{{Cite journal|last=Banfield |first=Alexander William Francis|year=1961|title=A Revision of the Reindeer and Caribou, Genus Rangifer |journal=Bulletin of the National Museum of Canada |volume=177 |number=66 |series=Biological Services}}</ref> eliminated ''R. t. caboti'' (the [[Labrador]] caribou), ''R. t. osborni'' (Osborn's caribou — from [[British Columbia]]) and ''R. t. terranovae'' (the [[Newfoundland (island)|Newfoundland]] caribou) as invalid and included only [[barren-ground caribou]], renamed as ''R. t. groenlandicus'' (formerly ''R. arcticus'') and woodland caribou as ''R. t. caribou''. However, Banfield made multiple errors, eliciting a scathing review by [[Ian McTaggart-Cowan]] in 1962.<ref>{{Cite journal |last=McTaggert-Cowan |first=Ian |date=1962 |title=Reviews: A revision of the reindeer and caribou, genus Rangifer by A. W. F. Banfield 1961 |journal=Canadian Field-Naturalist |volume=76 |pages=168–169 |doi=10.5962/p.342032 |oclc=1029734421|doi-access=free }}</ref> Most authorities continued to consider all or most subspecies valid; some were quite distinct. In his chapter in the authoritative 2005 reference work ''Mammal Species of the World'',<ref name="MSW3" /> referenced by the [[American Society of Mammalogists]], English zoologist [[Peter Grubb (zoologist)|Peter Grubb]] agreed with [[Valerius Geist]], a specialist on large mammals,<ref name="Geist1998" /><ref name="Geist-2007" /> that these subspecies were valid (i.e., before the recent revision): In North America, ''R. t. caboti'', ''R. t. caribou'', ''R. t. dawsoni'', ''R. t. groenlandicus'', ''R. t. osborni'', ''R. t. pearyi'', and ''R. t. terranovae''; and in Eurasia, ''R. t. tarandus'', ''R. t. buskensis'' (called ''R. t. valentinae'' in Europe; see below), ''R. t. phylarchus'', ''R. t. pearsoni'', ''R. t. sibiricus'' and ''R. t. platyrhynchus''. These subspecies were retained in the 2011 replacement work ''[[Handbook of the Mammals of the World]] Vol. 2: Hoofed Mammals''.<ref name="HBW" /> Most Russian authors also recognized ''R. t. angustirostris'', a forest reindeer from east of [[Lake Baikal]].<ref>Flerov, C.C. (1952) Mammals: Musk deer and deer. In: Fauna of the USSR. Academy of Sciences, Moscow and Leningrad, USSR, 222-247.</ref><ref name="Mizin-2018b" /><ref name="Rozhkov-2020" />

However, since 1991, many genetic studies have revealed deep divergence between modern tundra reindeer and woodland caribou.<ref name="Røed, K.H. 1991">Røed, K.H.; Feruson, M.D.; Crête, M.; Bergerud, A.T. (1991) Genetic variation in transferrin as a predictor for differentiation and evolution of caribou from [[eastern Canada]]. Rangifer 11: 65-74.</ref><ref name="Flagstad" /><ref name="Courtois-2003">{{Cite journal |last=Courtois |first=Rehaume |date=2003 |title=Significance of caribou (''Rangifer tarandus'') ecotypes from a molecular genetics viewpoint |journal=[[Conservation Genetics]] |volume=4 |issue=3 |pages=393–404|doi=10.1023/A:1024033500799 |bibcode=2003ConG....4..393C |s2cid=34394002 }}</ref><ref>{{Cite book |last=Couturier |first=Serge |title=Populations, metapopulations, ecotypes and subspecies of caribou in Quebec & Labrador: an exploratory discussion. In: McFarlane, K.; Gunn, A.; Strobeck, C. (eds.) Proceedings from the Caribou Genetics and Relationships Workshop (K. and C. Strobeck, eds.) |publisher=Department of Natural Resources and Environment, Government of the Northwest Territories |year=2003 |location=[[Edmonton, Alberta]] |pages=59–70}}</ref><ref name="Cronin-2003">{{Cite journal |last=Cronin |first=Matthew A. |date=2003 |title=Genetic variation in caribou and reindeer (''Rangifer tarandus'') |journal=[[Animal Genetics]] |volume=34 |issue=1 |pages=33–41|doi=10.1046/j.1365-2052.2003.00927.x |pmid=12580784 }}</ref> Geist (2007) and others continued arguing that the woodland caribou was incorrectly classified, noting that "true woodland caribou, the uniformly dark, small-maned type with the frontally emphasized, flat-beamed antlers", is "scattered thinly along the southern rim of North American caribou distribution". He affirms that the "true woodland caribou is very rare, in very great difficulties and requires the most urgent of attention."<ref name="Geist">{{Cite journal |last1=Geist |first1=Valerius |year=2007 |title=Defining subspecies, invalid taxonomic tools, and the fate of the woodland caribou |journal=[[Rangifer (journal)|Rangifer]] |volume=27 |issue=4 |page=25 |doi=10.7557/2.27.4.315 |doi-access=free}}</ref>

==== Ecotypes ====
In 2011, noting that the former classifications of ''Rangifer tarandus'', either with prevailing [[taxonomy]] on subspecies, designations based on [[ecotype]]s, or natural population groupings, failed to capture "the variability of caribou across their range in Canada" needed for effective subspecies conservation and management, COSEWIC developed Designatable Unit (DU) attribution,<ref name="COSEWIC2011DUReport" /> an adaptation of "evolutionary significant units".<ref>{{Cite book |last=Waples |first=Robin S. |title=Evolutionary significant units and the conservation of biological diversity under the Endangered Species Act. In: Nielson, J.L. (ed.) Evolution and the aquatic ecosystem: Defining unique units in population conservation |publisher=American Fisheries Society Symposium 17 |year=1995 |location=Bethesda, Maryland |pages=8–27}}</ref> The 12 designatable units for caribou in Canada (that is, excluding Alaska and Greenland) based on ecology, behavior and, importantly, genetics (but excluding [[Morphology (biology)|morphology]] and archaeology) essentially followed the previously named subspecies distributions, without naming them as such, plus some ecotypes. Ecotypes are not [[Phylogenetics|phylogenetically]] based and cannot substitute for taxonomy.<ref>Cronin, M.A. (2006) A proposal to eliminate redundant terminology for intra-species groups. Wildlife Society Bulletin 34: 237-241.</ref>

==== Genetic, molecular, and archaeological evidence ====
Meanwhile, [[Genome|genetic data]] continued to accumulate, revealing sufficiently deep divisions to easily separate ''Rangifer'' back into six previously named species and to resurrect several previously named subspecies. Molecular data showed that the Greenland caribou (''R. t. groenlandicus'') and the [[Svalbard reindeer]] (''R. t. platyrhynchus''), although not closely related to each other, were the most genetically divergent among ''Rangifer'' clades;<ref name="Yannic-2013" /> that modern (see [[Reindeer#Evolution|Evolution]] above) Eurasian tundra reindeer (''R. t. tarandus'' and ''R. t. sibiricus'') and North American barren-ground caribou (''R. t. arcticus''), although sharing ancestry, were separable at the subspecies level; that Finnish forest reindeer (''R. t. fennicus'') clustered well apart from both wild and domestic tundra reindeer<ref name="Rozhkov-2020" /> and that boreal woodland caribou (''R. t. caribou'') were separable from all others.<ref name="mtDNA2">{{Cite journal |last1=Cronin |first1=M. A. |last2=MacNeil |first2=M. D. |last3=Patton |first3=J. C. |year=2005 |title=Variation in Mitochondrial Dna and Microsatellite Dna in Caribou (''Rangifer tarandus'') in North America |journal=Journal of Mammalogy |volume=86 |issue=3 |pages=495–505 |doi=10.1644/1545-1542(2005)86[495:VIMDAM]2.0.CO;2 |doi-access=free}}</ref><ref>Cronin, M.A.; MacNeil, M.D.; Patton, J.C. (2006) Mitochondrial DNA and microsatellite DNA variation in domestic reindeer (''Rangifer tarandus tarandus'') and relationships with wild caribou (''Rangifer tarandus granti'', ''Rangifer tarandus groenlandicus'', and ''Rangifer tarandus caribou''). Journal of Heredity 97: 525-530. {{doi|10.1093/jhered/esl012}}</ref> Meanwhile, archaeological evidence was accumulating that Eurasian forest reindeer descended from an extinct forest-adapted reindeer and not from tundra reindeer (see [[Reindeer#Evolution|Evolution]] above); since they do not share a direct [[Common descent|common ancestor]], they cannot be [[Biological specificity#conspecific|conspecific]]. Similarly, woodland caribou diverged from the ancestors of Arctic caribou before modern barren-ground caribou had evolved, and were more likely related to extinct North American forest reindeer (see [[Reindeer#Evolution|Evolution]] above). Lacking a direct shared ancestor, barren-ground and woodland caribou cannot be conspecific.

[[Sequencing|Molecular data]] also revealed that the four western Canadian  montane ecotypes are not woodland caribou: they share a common ancestor with modern barren-ground caribou / tundra reindeer, but distantly, having diverged > 60,000 years ago<ref>McDevitt, A.D.; Mariani, S.; Hebblewhite, M.; Decesare, N.J.; Morgantini, L.; Seip, D.R.; Weckworth, B.V.; Musiani. M. (2009) Survival in the Rockies of an endangered hybrid swarm from diverged caribou (''Rangifer tarandus'') lineages. Molecular Ecology 18: 665-679.</ref><ref name="Horn-2018" /><ref name="Yannic-2013">Yannic, G.; Pellissier, L.; Ortego, J.; Lecomte, N.; Couturier, S.; Cuyler, C.; Dussault, C.; Hundertmark, K.J.; Irvine, R.J.; Jenkins, D.A.; Kolpashikov, L.; Mager, K.; Musiani, M.; Parker, K.L.; Røed, K.H.; Sipko, T.; Þórisson, S.G.; V.Weckworth, B.; Guisan, A.; Bernatchez, L.; Côté, S.D. (2013) Genetic diversity in caribou linked to past and future climate change. Nature Climate Change 4: 132-137. {{doi|10.1038/NCLIMATE2074}}</ref> — before the modern ecotypes had evolved their cold- and darkness-adapted physiologies and mass-migration and aggregation behaviors (see Evolution above). Before Banfield (1961), taxonomists using cranial, dental and skeletal measurements had unequivocally allied these western montane ecotypes with barren-ground caribou, naming them (as in Osgood 1909<ref name="Osgood-1909">Osgood, W.H. (1909) Biological investigations in Alaska and Yukon Territory. US Department of Agriculture Biological survey of North American fauna 1: 1-285.</ref> Murie, 1935<ref name="Murie-1935" /> and Anderson 1946,<ref name="Anderson-1946" /> among others) ''R. t. stonei'', ''R. t. montanus'', ''R. t. fortidens'' and ''R. t. osborni'', respectively,<ref name="Murie-1935">{{Cite book |last=Murie |first=Olaus J. |title=Alaska-Yukon caribou |publisher=United States Department of Agriculture Bureau of Biological Survey Vol. 54 |year=1935 |location=Washington D.C. |pages=1–93}}</ref><ref name="Anderson-1946">{{Cite book |last=Anderson |first=Rudolph M. |title=Catalogue of Canadian Recent Mammals |publisher=National Museum of Canada Bulletin No. 102, Biological Series 31 |year=1946 |location=Ottawa, Ontario |pages=1–238}}</ref> and this phylogeny was confirmed by genetic analysis.

==== Novel genetics-based clades ====
DNA also revealed three unnamed clades that, based on genetic distance, genetic divergence and shared vs. private [[haplotype]]s and [[allele]]s, together with ecological and behavioral differences, may justify separation at the subspecies level: the Atlantic-[[Gaspé Peninsula|Gaspésie]] caribou (COSEWIC DU11),<ref name="Courtois-2003" /><ref name="Yannic-2018" /> an eastern montane ecotype of the boreal woodland caribou, and the [[Baffin Island]] caribou.<ref name="Jenkins-2018">{{Cite journal |last=Jenkins |first=Deborah A. |date=2018 |title=Population structure of caribou in an ice-bound archipelago |journal=Diversity and Distributions |volume=24 |issue=8 |pages=1092–1108|doi=10.1111/ddi.12748 |bibcode=2018DivDi..24.1092J |s2cid=90854394 |doi-access=free }}</ref> Neither one of these clades has yet been formally described or named.

Jenkins et al. (2012) said that "[Baffin Island] caribou are unique compared to other Barrenground herds, as they do not overwinter in forested habitat, nor do all caribou undertake long seasonal migrations to calving areas." It also shares a mtDNA haplotype with Labrador caribou, in the North American lineage (i.e., woodland caribou).<ref name="mtDNA2"/> Røed et al. (1991)<ref name="Røed, K.H. 1991"/> had noted:<blockquote>Among Baffin Island caribou the TFL2 allele was the most common allele (p=0.521), while this allele was absent, or present in very low frequencies, in other caribou populations (Table 1), including the Canadian barren-ground caribou from the Beverly herd. A large genetic difference between Baffin Island caribou and the Beverly herd was also indicated by eight alleles found in the Beverly herd which were absent from the Baffin Island samples.</blockquote>Jenkins et al. (2018)<ref name="Jenkins-2018" /> also reported genetic distinctiveness of Baffin Island caribou from all other barren-ground caribou; its genetic signature was not found on the mainland or on other islands; nor were [[Reindeer distribution#Ahiak, Beverly and Qamanirjuaq caribou herds|Beverly herd]] (the nearest mainly barren-ground caribou) alleles present in Baffin Island caribou, evidence of reproductive isolation.

These advances in ''Rangifer'' genetics were brought together with previous morphological-based descriptions, ecology, behavior and archaeology to propose a new revision of the genus.<ref name="Harding-2022" />