EURASIAN WAPITI CERVUS CANADENSIS

It took a considerable amount of time to accept the idea that the Canadian stag or wapiti constitutes a distinct species. There were however doubtless genetic, ecological, and biological evidence over the last several decades. This evidence failed to sway the conservative, oversimplified view on the taxonomy of C. canadensis, which was initially regarded as a group of subspecies of C. elaphus. Nonetheless, the history of discovery and exploration of this species is very long. In 1777, Erxleben introduced the binomial species name C. canadensis for the wapiti, though the exact characteristics of this deer, aside from its larger size, remained unclear. Schreber (1836) proposed a new species name for a large form of North American deer, Cervus strongyloceros, accompanied by a brief description and figures representing the pelage color of a female and a shed antler. In the same work, Schreber (1836) published a description of “ C. canadensis Brisson ” supplemented with a figure of a stag with fantastic undulated antlers, suggesting that the author was poorly acquainted with this species.

Severtzoff (1873, 1876) was the first to notice the striking resemblance between the Siberian Cervus maral Gray, 1860 (distinct from the name C. elaphus maral given to the Caspian red deer) and the North American C. canadensis. Lydekker regarded the wapiti as a true species, C. canadensis, and introduced the new subspecies name C. canadensis asiaticus Lydekker, 1898 for the Asian wapiti.

The “lumping” approach to the systematics of the “elaphine” deer (the species complex of C. elaphus and C. canadensis) dominated the zoological literature of the second half of the 20th century. American wapiti, Asian maral, and izubr stags were considered subspecies of the common red deer, C. elaphus (Heptner & Zalkin 1947; Ellerman & Morrison-Scott 1951; Flerov 1952; Sokolov 1959; Geist 1998). Heptner & Zalkin (1947) proposed that populations of Siberian wapiti in natural conditions are genetically isolated from Western and Central Asian red deer, although they noted that the areas of distribution of Asian wapitis and red deer forms never overlap, suggesting they are likely subspecies of the same species. The ease of hybridization between wapiti and red deer was also considered by Heptner & Zalkin (1947) as an argument for including various geographical elaphine forms as subspecies of the single species C. elaphus.

Flerov (1952) grouped Asian wapitis in the subspecies C. elaphus canadensis alongside North American wapitis. However, according to Sokolov (1959), the remarkable similarity in pelage coloring and antler shape of C. elaphus sibiricus and C. elaphus canadensis should be regarded as an evolutionary parallelism.He preferred to maintain these two elaphine forms as distinct subspecies of C. elaphus.

The caution in distinguishing red deer and wapiti as two independent species appears to stem from a lack of detailed morphological, biological, and ethological studies. Body size, the only readily available feature distinguishing red deer and wapiti, varies greatly within the better-known C. elaphus (Heptner & Zalkin 1947; Flerov 1952; Geist 1998). On the other hand, the simplified viewpoint on the taxonomy of red deer and wapiti has reduced scholars’ interest in comparative morphological studies of these two species. Consequently, there is a dearth of comparative data on cranial and dental morphology between the two species. The only known morphological characteristics of wapiti pertain to antler shape, which is used in subspecies descriptions.

However, the reproductive isolation of wapiti and Western red deer populations in natural conditions are ensured by ethological, biological, and ecological differences (Heptner & Zalkin 1947; Geist 1998). Considering that Western red deer and wapiti occupy different ecological niches, and the genetic data opposing Western red deer to wapiti and sika deer, we regard wapiti as a true species C. canadensis, clearly distinct from red deer C. elaphus.

The reassessment of taxonomic criteria for “elaphine” deer came much later with genetic studies revealing significant phylogenetic distances between European red deer and Asian and American wapitis (Kuwayama & Ozawa 2000; Polziehn & Strobeck 2002; Ludt et al. 2004; Pitra et al. 2004). Molecular data reinstated the species status for C. canadensis (Polziehn & Strobeck 2002), further supported by ecological, physiological, ethological, and biological evidence, including semi-lethal hybridization between C. canadensis and C. elaphus (Schonewald 1994; Geist 1998; Croitor & Obada 2018).

In China, three subspecies are currently recognized: the Gansu wapiti (C. canadensis kansuensis Pocock, 1912), the Tibet and Bhutan wapiti (C. canadensis wallichi Cuvier, 1823), and the Sichuan wapiti (C. canadensis macneilli Lyddeker, 1909; Fig. 2B). These subspecies are distinguished by their relatively smaller antlers with less developed distal portions, often characterized by a simple fork (Cuvier 1823; Lydekker 1896; Pocock 1912; Geist 1998). The distinctions between subspecies primarily lie in the patterns and overall coloration of their pelage, including the shape and hue of the rump patch, which plays a role in social communication.

Four other subspecies are recognized, bringing the total number of Asian subspecies to seven: the Altai wapiti (C. canadensis sibiricus Lydekker, 1898), the Tien-Shan wapiti (C. canadensis songaricus Erxlerben, 1777), the Manchurian wapiti (C. canadensis xanthopygus Edwards, 1867), and the Ala-Shan wapiti (C. canadensis alashanicus Bobrinskii & Flerov, 1935). These subspecies are characterized by larger antlers with a strongly developed crown portion consisting of three tines, with the first crown tine being the longest and the strongest.

The most advanced evolutionary specializations are found in North American wapiti.Five subspecies exist in North America: the Roosevelt wapiti (C. canadensis roosevelti Merriam, 1897), the Tule wapiti (C. canadensis nannodes Merriam, 1905), the Manitoba wapiti (C. canadensis manitobensis Millais, 1915), and the Rocky Mountain wapiti (C. canadensis nelsoni Bailey, 1935). The southernmost subspecies of North American wapiti, C. canadensis merriami Nelson, 1902, which was characterized by a tendency to develop palmated antlers, is now extinct.