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Thos vs. Canis




[This note is the result of the encounter with  “Thos aureus nubianus” as scientific designation of a subspecies of the Golden jackal (in Ellerman/Morrison-Scott 1966: 221) and subsequent efforts to ascertain the significance of Thos.]

The basis for the Thos vs. Canis controversy (if a basically minor taxonomic hiccup deserves to be called a controversy) was laid in 1816 in the third volume of Lorenz Oken’s Lehrbuch der Naturgeschichte (1815-16) where the author found sufficient similarities in the dentition of the jackals (excluding Canis simensis that had yet to be discovered) and the North American coyotes to place these species into a new separate genus. Oken named this proposed genus Thos after the classical Greek word θώς, ‘a small fox-like carnivore’ (Kaegi 1904: 415) which, in all likelihood, referred to the Golden jackal.


I have seen no evidence that Oken’s Thos theory had any immediate impact on taxonomy and/or taxonomic nomenclature. In 1914, nearly a century later, Edmund Heller  resurrected and summarized Oken’s observations, embraced the theory of the new genus





 Canine teeth  

   “long, slender, Vulpes-like”  

   “much thicker and shorter”

 Outer incisors  


   “greatly enlarged”,  “more than twice the size of the inner ones”

 Carnassial teeth  



 Upper molars  

  “with well marked cingula”   

  “without definite cingula”

 Fourth lower premolar  

   with a minute third cusp on posterior border  

without such a cusp


 Differences in dentition of Thos and Canis

 Information abstracted from Edmund Heller (1914: 1)



and named five newly discovered subspecies of African jackals accordingly: Thos adustus bweha Heller 1914: 3; Thos adustus notatus Heller 1914: 4; Thos aureus bea Heller 1914: 5; Thos mesomelas elgonae Heller 1914: 6; Thos mesomelas mcmillani  Heller 1914: 6.


Cabrera (1921: 263, 264) has Thos as the generic element in the names of three African subspecies of the Golden jackal:  Thos aureus nubianus to replace Gretzmar’s Canis variegatus for the subspecies now known as Canis aureus soudanicus (Thomas, 1903); Thos lupaster maroccanus for the Moroccan race of Golden jackal that he discovered, described and named (today’s Canis aureus maroccanus, Cabrera, 1921); and finally Thos lupaster algirensis (today’s Canis aureus algirensis, Wagner, 1841) from which he had to distinguish his newly found maroccanus. (see Ellerman/Morrison-Scott, 1966: 221 and 222, and Cabrera, 1932: 107). If and how Cabrera explained why he preferred Thos over Canis I do not know; I have yet to see a copy of the article.


In his 1932 monograph on the mammals of Morocco, Angel Cabrera (who, I suspect, is one and the same man as the afore mentioned Cabrera) briefly touches upon the question whether or not the presence of a cingulum on the upper molars of the jackals and its corresponding absence in the rest of Canis can justify a subdivision of the genus Canis. In his statement he sounds ambivalent: “… cabría distinguir dos grupos de especies dentro del mismo género, o si se quiere, dos subgéneros, y en este caso los chacales formarían el subgénero Vulpicanis” (p. 106. ‘… one could distinguish two groups of species within one and the same genus or, if one desires, two subgenera, in which case the jackals would constitute the subgenus Vulpicanis’). In practice, he chooses the undivided-genus alternative and refers to the jackals as Canis lupaster maroccanus and so on. He is not at all ambivalent, however, about the word Thos: It and Oken’s other names should not be allowed porque este autor no siguió las verdadera nomenclatura binaria (‘did not follow the true binominal nomenclature’). It is not immediately obvious why Canis lupaster maroccanus should be more binominal than Thos lupaster maroccanus.

Note: Vulpicanis Blainville, 1837 = Canis aureus Linnaeus, 1758,


Allen (1939: 193-196 and in Index), with reference to Heller’s article but without any discussion, lists 22 African subspecies of jackals under the genus Thos Oken: six side-striped, ten golden (surely, his Thos adustus grayi is an oversight and should read  Thos aureus grayi), and six black-backed jackals (plus some duplications and two subspecies of uncertain status).-- The Simean (or Ethiopian) jackal he places outside of Thos into a separate genus Simenia Gray (192).


In 1947, Kretzoi proposed Thos aureus ecsedensis as replacement name for Canis aureus hungaricus, Ehik, 1938 (see Ellerman/Morrison-Scott, 1966: 222).


As A.Cabrera’s discussion indicates (1932: 106, see above), the concept of Thos can be and has been questioned on two fronts – on the proper evaluation of the underlying zoological observations and on the adequacy of its taxonomic terminology.


To address the latter first, Oken’s idiosycratic nomenclatorial ways have aroused the scorn of a number of zoological systematists: J.A. Allen (1902), P. Matschie (1903), Stiles and Orleman (1927), A, Cabrera (1932 and again 1943), P. Hershkovitz (1949), and Opinion 417 (1956) of the ICZN have made abundantly clear why Oken’s names should be “not available.”  When we, to stay with our narrower topic, look at his four Thos names for jackals (1816: 1034, as quoted by Allen, 1902: 377:  Thos C[anis] ceylonensis,  Thos C, mesomelas, Thos C. barbarus,  and Thos vulgaris) it is indeed difficult to find fault (leaving aside matters of style and grammar) with Hershkovitz’s statement that “Thos, as used by Oken, may be translated into modern systematics as a generic, a specific, a pre-Linnaean classical, and a vernacular name, according to the interpreter.” (293) However, in accepting Cabrera’s subgeneric term Vulpicanis as “valid pertinent name’ (1949: 293) for Oken’s Thos (an opinion I have not seen repeated anywhere) Hershkovitz implicitly subscribes to the subdivision of Canis. And, as modified in its use by Heller (1914), Cabrera (1921), Allen (1939), Thos, clearly is a generic term and no longer presents the hierarchical problems that incensed the systematists.


When evaluating the observations presented in the above table, the reader should be aware that nearly all the descriptive words (long, small, large, thick etc.) are relative terms without a reference measure and that the argument does not take into account (at least not in Heller’s summary) the size differences between the species which can be considerable, e.g. wolf vs. side-striped jackal.  The authors of the “Review of the Family Canidae, with a Classification by Numerical Methods” are not swayed by Heller’s argument. They judge the characters to be “not definitive” and “all very variable in their development.”  Not only do they reject the notion of a new genus Thos for coyotes and jackals, but actually put forth the Golden jackal (Canis aureus) as “the most typical of the Canis species … for it is of medium size and has no outstanding features. The pelage is typical of the family and the wide range that it covers precludes specialization.” (J. Clutton-Brock et al., 1976: 142 and 147f.).


Oken, Allen, Cabrera 1921, and Kretzoi are mere footnotes in the taxonomy of jackals. Heller’s name and the names he gave them live on in the subspecies of jackals he discovered and described and so does Cabrera’s in the case of the Moroccan jackal. Only the genus has changed -- from Thos to Canis.


The classification of the coyote was not affected  by the Oken/Heller proposal of the new genus Thos. To be sure, Miller (1924: 150) still has, in the section “Genus CANIS Linnaeas,” the subordinate heading “Subgenus Thos Oken (Jackals and Coyotes.)” and backs this up with an (inaccurate) reference to Heller. In the reworked version of this book (Miller 1955), the arguments of, among others, Hershkovitz (see above) and Jackson (see below) led him to drop Thos both as an available scientific term and as a viable subgenus of Canis.

In his still definitive study of the taxonomy of the coyote, Jackson (1951: 233) had, in response to Miller (1924: 150), queried whether Heller had seriously looked at specimens of coyotes prior to his 1914 article and thought the characters to be “not sufficiently important or stable to warrant subgeneric recognition for the group” (233). That was that, and for the coyote classification, too, Thos was toast.



Allen, Glover M. 1939. “A Checklist of African Mammals”. Bulletin of the

    Museum of Comparative Zoology at Harvard College. 83: 1-763.

Allen, J.A. 1902. “Mammal names proposed by Oken in his Lehrbuch der

    Zoologie”.  Bulletin of the American Museum of Natural History, 16: 373-379.

Cabrera 1921. [Title unknown] In: Boletín de la Real Societad Española de

    Historia Natural. Vol. 21. (as referenced by A. Cabrera 1932: 107)

Cabrera, Angel 1932.  Los mamíferos de Marruecos (= Trabajos del Museo

    Nacional de Ciencias Naturales, Serie Zoológica, Núm.57). Madrid, Spain.

Cabrera, Angel 1943.[Tit;e unknown] In:  Ciencia, Mexico. Vol. 4, pp. 108-111

    (as referenced by Hershkovitz 1949: 290)

Clutton-Brock, Juliet, Gordon B. Corbet & Michael Hills 1976. “A Review of the

    Family Canidae, with a Classification by Numerical Methods.”  Bulletin of the

    British Museum (Natural History) Zoology, vol. 20, no. 3, pp. 117-199.

Ellerman, J.R. and T.G.S. Morrison-Scott 1966. Checklist of Palaearctic and

    Indian Mammals 1758 to 1946. 2nd ed. British Museum (Natural History),


Heller, Edmund  1914. “New Subspecies of Mammals from Equatorial Africa,” 

    Smithsonian Miscellaneous Collections, vol. 63, no. 7, pp. 1 – 12.

Hershkovitz, Philip 1949 “Status of names credited to Oken, 1816”. Journal of

    Mammalogy, vol. 30.3, 289-301, esp. 293.

ICZN (= International Commission for Zoological Nomenclature), opinion 417

Jackson, Hartley H .T. 1951. Classification of the Races of  the Coyote.

    (= Part II of  Stanley P. Young, The Clever Coyote). A Wildlife Management

    Institute Publication. Washington. D.C.

Kaegi, Adolf (Ed.) 1904. Benselers griechisch-deutsches Schulwörterbuch.

    12th ed., Teubner Verlag: Leipzig und Berlin.

Kretzoi, M. 1947. [Title unknown] In: Annales historico-naturales musei

    nationalis  Hungarici, vol. 40, Budapest, Hungary, 1947.

    (as referenced by Ellerman/Morrison-Scott 1966: 222)

Matschie, P. 1904. [Title unknown] In: Sitzungsberichte der Gesellschaft natur-

    forschender Freunde zu Berlin, 4: 55f.

    (as referenced by Hershkovitz 1949: 289)

Miller, Gerrit S., Jr. 1924.  List of North American Recent Mammals. Bulletin

     of the United States National Museum, 128: 1-673.

Miller, Gerrit S.,Jr. 1955.  List of North American Recent Mammals.

    Bulletin of the United States National Museum 205.

Oken, Loranz 1815-1816. Lehrbuch der Naturgeschichte. Vol,. 3: Zoologie.

    August Schmid und Comp., Jena.

Stiles, C.W. and M.B. Orleman, 1927. [Title unknown]. In: Hygienic Laborator

    Bulletin, 145: 29.

    (as referenced by Cabrera 1932:106, and Hershkovitz 1949: 289)



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