Evaluating the Taxonomic Status of the Mexican Gray Wolf and the Red Wolf (2019) / Chapter Skim
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5 Is the Red Wolf a Valid Taxonomic Species?
5 Is the Red Wolf a Valid Taxonomic Species?
Pages 51-72
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From page 51... ...
population descends from the original red wolf population or instead is the result of admixture between coyotes and gray wolves. A BRIEF TAXONOMIC HISTORY OF THE RED WOLF Audubon and Bachman (1851)
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From page 52... ...
, (2) Is there evidence for the distinctiveness of contemporary red wolf populations from gray wolves and coyotes?
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From page 53... ...
examined all available red wolf specimens collected before 1920 from Louisiana, Alabama, and Florida, a period in which coyotes were absent from the southeastern United States (Nowak, 2002) , and evaluated nine cranial and six tooth characters that they had previously found to differentiate among wolves, coyotes, and domestic dogs (C.
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From page 54... ...
also examined these specimens within an analysis of the same skull characters from specimens of gray wolves, coyotes, and domestic dogs (Nowak, 1979; Figures 8-13)
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From page 55... ...
However, given that coyotes were absent from the southeastern United States before 1920, these red wolf specimens could not represent firstor early-generation hybrids between wolves and coyotes. Whether they represent a long-standing hybrid lineage or a longstanding species intermediate in size and morphology between coyotes and wolves cannot be determined from this analysis alone.
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From page 56... ...
They found that the mtDNA haplotypes of these specimens clustered within the general coyote clade. All three studies are compatible with the hypothesis that the historical red wolf in the eastern United States was more closely related to modern coyotes than to gray wolves, which is in line with what has been found with the extant managed red wolf population (see later sections)
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From page 57... ...
Analyses of Admixture Results of most analyses of admixture suggest that the red wolf population is admixed with genetic components of gray wolves, coyotes, and perhaps other canids. The most direct evidence for admixture is the D (ABBA-BABA)
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From page 58... ...
In particular, if the inferred ancestry fragments from red wolves closely match potential donor gray wolf and coyote populations from regions where they might have introgressed during the coyote eastward expansion, this would provide support for the recent admixture hypothesis. Finding: The red wolf population shows evidence of past genetic contributions from populations related to gray wolves, coyotes, or both.
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From page 59... ...
However, if the current red wolf population has been formed as an anthropogenic mixture between gray wolves and coyotes postdating the European colonization (i.e., after ~1500 AD) of the Americas, this could affect considerations regarding species status (see Chapter 2, Box 2-1)
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From page 60... ...
Subsequent to the divergence between coyote and red wolves, the captive/managed red wolf population has received substantial gene flow from coyotes and gray wolves as indicated in the figure. The timing of this gene flow has not been dated.
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From page 61... ...
Finding: The timing of the admixture between red wolves and other canids is still unresolved, but red wolves have divergent genetic ancestry that predates European colonization. Distinct Genomic Ancestry A relevant question is the degree to which the current red wolf population harbors genetic material of potential adaptive value that is not found in gray wolves or coyotes.
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From page 62... ...
While both of these analyses show that red wolves harbor genetic variability that would not be expected in a simple mixture of chosen reference gray wolf and coyote populations, they still do not show a connection between this genetic variability and the historical red wolf populations in the eastern United States. Finding: The red wolf has some degree of genetic ancestry not found in reference populations of western gray wolves or coyotes.
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From page 63... ...
IS THERE EVIDENCE FOR CONTINUITY BETWEEN THE HISTORICAL RED WOLF POPULATION AND THE PRESENT MANAGED POPULATIONS? Paleontology and Morphology Based on dental analyses of paleontological (around 10,000 years ago)
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From page 64... ...
Genetics Because wolves are extinct in the southwestern United States, the only sure way to determine whether the managed red wolf population is a remnant of the original canid species in southwestern United States is to use ancient DNA from museum specimens. Unfortunately, at the moment there are no genome-wide data available from red wolves from before the anthropogenic expansion of the coyote range.
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From page 65... ...
Finding: Genetic continuity between the managed red wolf population and the historical wolf in the eastern United States cannot be firmly established without genomic data from ancient specimens. However, the patterns of genetic variability are compatible with the hypothesis that the red wolf shares a fraction of its genetic history with a canid distinct from modern reference coyotes and gray wolves.
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From page 66... ...
. While the red wolf was originally the only canid present in the eastern United States, the anthropogenic alteration of the eastern forests and the reduction of the wolf population caused by wolf control programs allowed the expansion of the coyote into this area in the second half of the 20th century (Hinton et al., 2017; Kilgo et al., 2010; Levy, 2012)
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From page 67... ...
This requirement of larger home ranges is consistent between the original natural population and the extant managed population in North Carolina. Food Habits It has been hypothesized that the red wolf was originally adapted to hunt for white-tailed deer (Odocoileus virginianus; Waples et al., 2018)
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From page 68... ...
A second line of evidence for a distinct ancestry of extant red wolves comes from the recent observation of canids on Galveston Island, which have the appearance of red wolves and which share private alleles with red wolves. These lines of evidence, together with estimates of the introgression tract length distribution, also suggest that the captive/managed red wolf population cannot be purely a product of hybridization between gray wolves and coyotes that occurred during the recent anthropogenic eastward expansion of the coyote range.
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From page 69... ...
and maintenance of some unique genetic ancestry, a species status, possibly as a historically admixed species, is the most appropriate designation for the red wolf. However, genomic DNA from historical red wolf specimens could help clarify the issue regarding the continuity between historical and extant red wolves.
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From page 70... ...
2013. Evaluating the ability of Bayesian clustering methods to detect hybridiza tion and introgression using an empirical red wolf data set.
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From page 71... ...
2018. Substantial red wolf genetic ancestry persists in wild canids of southwestern Louisiana.
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From page 72... ...
1991. Mitochondrial DNA analysis implying extensive hybridization of the endangered red wolf Canis rufus.
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