Comments on Taxonomy and Geographic Distribution of Some North American Marsupials, Insectivores Part 2

1890. _Spilogale gracilis_ Merriam, N. Amer. Fauna, 3:83, September 11, type from bottom of canyon, Grand Canyon, Arizona.

1890. _Spilogale leucoparia_ Merriam, N. Amer. Fauna, 4:11, October 8, type from Mason, Mason County, Texas.

1891. _Spilogale phenax arizonae_ Mearns, Bull. Amer. Mus. Nat.

Hist., 3:256, June 5, type from near Fort Verde, Yavapai County, Arizona.

1897. _Spilogale ambigua_ Mearns, Preliminary diagnoses of new mammals ... from the Mexican boundary line, p. 3, January 12 [reprinted in Proc. U.S. Nat. Mus., 20:460, December 24, 1897], type from summit of Eagle Cliff Mtn., 2 mi. S of Monument No. 5 of Emory's Survey which, according to Miller (U.S. Nat. Mus. Bull., 128:134, April 29, 1924), is "Eagle Mountain, Chihuahua, Mexico, about four miles south of Dona Ana County, New Mexico."

In 1906 (N. Amer. Fauna, 26:1-55, 10 pls., November 24) A. H. Howell's "Revision of the skunks of the genus Spilogale" was published and the four names listed above were retained by him as applying to four species (not subspecies). His map (_op. cit._, pl. 1) showing the geographic distribution of the four kinds looks reasonable enough at first inspection and does not indicate any overlapping of the geographic ranges of the species in question, but if a map be made by plotting the localities of occurrence recorded by Howell (_op. cit._), for specimens examined by him, a notably different geographic distribution is shown. For one thing the geographic ranges of _gracilis_, _leucoparia_, _arizonae_ and _ambigua_ coincide over a considerable part of Arizona. Also, specimens collected in recent years from Arizona and adjoining areas do not readily fit into the "species" recognized by Howell; some specimens are structurally intermediate between two or more of these species and other specimens combine the diagnostic characters ascribed to two or more of the alleged species. For these and other reasons a re-appraisal of the application of the names mentioned above long has been indicated.

Before re-appraising the names it is pertinent to recall that Howell's paper in 1906 on _Spilogale_ was only the second revisionary paper that he prepared. It was prepared by a man who at that time lacked much taxonomic experience, and who held to a morphotype concept.

Howell worked under the guidance, in the literal sense, of Dr. C. Hart Merriam. The concept of species and subspecies held by Merriam fortunately was recorded by him (Jour. Mamm., 1:6-9, November 28, 1919). Merriam's reliance on degree of difference and his disregard of intergradation were naturally (and necessarily, we think, in Howell's work in 1906) adopted by Howell. For example, of six specimens from Point Reyes in west-central California, a place less than ten miles from the type locality of _Spilogale phenax phenax_, Howell (_op.

cit._:33) a.s.signed one specimen to the subspecies _Spilogale phenax latifrons_! _S. p. latifrons_ occurs in Oregon and in northern California--no nearer than 200 miles to Point Reyes. Howell's a.s.signment of this specimen to _S. p. latifrons_ was not a _lapsus_, as persons with the modern (geographic) concept of a subspecies would be likely to suppose. Howell's a.s.signment of the one specimen to _S.

p. latifrons_ and the other five specimens to _S. p. phenax_ was intentional, as he told one of us (Hall). He explained that he relied upon the morphological characters of the individual animal instead of upon the morphological characters of a population of animals. To him, therefore, there was nothing inconsistent in his procedure in 1906.

Also, variation that was the result of difference in age and variation that was the result of individual deviation were not understood, or at least not taken into account, by Howell in 1906, nor by Merriam in 1890. For example, Merriam selected the most extensively white specimen available to him for the holotype of _Spilogale leucoparia_.

He, and Howell in 1906, used the extensiveness of the white areas of that particular specimen (see fig. 3, pl. 2, N. Amer. Fauna, 26, 1906) as a character diagnostic of the "species" _S. leucoparia_ although each of the authors had available two other specimens of _S.

leucoparia_ from the type locality, and all of the other referred specimens in the United States National Museum, that were less extensively white than the holotype. The _individual specimen_ was the primary basis for the species or subspecies and one selected specimen alone often was used in making comparisons between a given named kind and some other species or subspecies. Also, be it remembered, degree of difference, and not presence or absence of intergradation, was the basis on which subspecific _versus_ specific rank was accorded to a named kind of animal. Howell wrote on the labels of some specimens of _Spilogale_ "not typical" when the individuals differed from the type specimen in features that owe their existence to individual variation, and he wrote the same words on the labels of other specimens that had not yet developed mastoidal crests because the animals were not yet adult.

Anyone who examines the specimens that Howell used will do well to bear in mind the circ.u.mstances noted above concerning Howell's paper of 1906; otherwise the reasons for Howell's identifications of certain specimens can not be understood.

We have examined and compared the holotypes, and other specimens used by Howell. While doing so we have borne in mind the degree of individual variation well shown by each of several series of specimens (for example, that in six adult males, from the Animas Mountains of New Mexico, recorded by V. Bailey, N. Amer. Fauna, 53:339, 1932) and age variation (for example, that shown in specimens of _S. interrupta_ from Douglas County, Kansas). The degree of each of these kinds of variation, although considerable, is not extraordinary. That is to say, the variations are of approximately the same degree as we previously have ascertained to exist in _Mephitis mephitis_ and in _Mustela frenata_, two species that are in the same family, Mustelidae, as _Spilogale_. As a result of our comparisons, we conclude, first that the four names mentioned at the beginning of this account all pertain to one species, and second that the three names _S. gracilis_, _S. p. arizonae_ and _S. ambigua_, and probably also _S. leucoparia_, were based on individual variations in one subspecies. _S. gracilis_ has priority and will apply; the other names are properly to be arranged as synonyms of it, as follows:

1890. _Spilogale gracilis_ Merriam, N. Amer. Fauna, 3:83, September 11.

1890. _Spilogale leucoparia_ Merriam, N. Amer. Fauna, 4:11, October 8.

1891. _Spilogale phenax arizonae_ Mearns, Bull. Amer. Mus. Nat.

Hist., 3:256, June 5.

1897. _Spilogale ambigua_ Mearns, Preliminary diagnoses of new mammals ... from the Mexican boundary line, p. 3, January 12.

Some information in support of the above arrangement, along with some other observations on _Spilogale_, are as follows: The type specimen of _Spilogale gracilis_ bears on the original skin-label in the handwriting of Vernon Bailey, the collector, the statement that the tail was imperfect. The recorded measurements of 400 for total length and 142 for length of tail, therefore, are presumed to be subject to correction. This presumption and the further circ.u.mstance that other specimens from Arizona and New Mexico are as large as specimens of comparable age and s.e.x that we have examined from Nevada and Utah of _Spilogale gracilis saxatilis_ Merriam, indicate that _S. g.

saxatilis_ differs less from the allegedly smaller _S. g. gracilis_ than was previously thought. Nevertheless, from north to south (for example, from northern Nevada to southern Arizona) there is an increase in extent of white areas at the expense of black areas of the pelage. As a result, the lateralmost white stripe in _S. g. saxatilis_ averages narrower (and often is wanting) than in _S. g. gracilis_. The absence, or narrowness, of the lateralmost white stripe seems to be the princ.i.p.al basis for recognizing _S. g. saxatilis_, just as the tendency to narrow rostrum in Coloradan specimens seems to be the princ.i.p.al basis for recognizing _Spilogale gracilis tenuis_ A. H.

Howell. Both _S. g. saxatilis_ and _S. g. tenuis_ are "poorly"

differentiated from _S. g. gracilis_ and from each other.

The holotype of _Spilogale ambigua_ Mearns is slightly smaller than other adult males of comparable age, and the braincase, relative to its width, is slightly deeper than in the average adult male. These variations, nevertheless, are within the range of individual variation, as also are those characterizing the holotype of _Spilogale phenax arizonae_ Mearns. The latter specimen is an adult male, with much inflated mastoidal bullae, nearly straight dorsal profile on the skull, relatively shallow braincase, and only slightly worn teeth.

The holotype of _Spilogale leucoparia_ Merriam, as pointed out above, is an extreme example of the extensiveness of the white areas of the pelage at the expense of the black areas. This feature occurs more often in the southwestern desert areas of the United States than it does farther north. In addition to the extensiveness of the white markings, the other two characters allegedly distinctive of _S.

leucoparia_ are broad and much flattened braincase and great degree of inflation of the mastoidal bullae. Although these three mentioned features do distinguish _S. leucoparia_ from _S. indianola_ to the eastward, they seem not to set _S. leucoparia_ apart from _S.

gracilis_ to the westward. For example, in Arizona some specimens are extensively white and some others have the braincase flattened and the mastoidal bullae much inflated. V. Bailey (N. Amer. Fauna, 53:339, 1932) refers to a specimen ([Male], No. 147252 USBS) from the head of the Rio Mimbres in New Mexico in which, as our comparisons show, the inflation of the mastoidal bullae exceeds that of any Texan specimen of _S. leucoparia_, the holotype included. Also, at the type locality of _S. leucoparia_, subadult male No. 188467 USNM and adult male No.

188468 USNM are narrower across the mastoidal region than is the holotype. In summary and review, specimens from the eastern part of the range heretofore ascribed to _S. leucoparia_ nearly all have much inflated mastoidal bullae whereas less than half of the specimens of _Spilogale_ from western New Mexico and Arizona have these bullae as greatly inflated; but, in No. 147252 from the head of the Rio Mimbres of New Mexico the inflation of the bullae is more extreme than in any specimen that we know of that has been referred to _S. leucoparia_.

If intergradation occurs between _Spilogale gracilis gracilis_ and _Spilogale indianola_ and between one or both of these kinds on the one hand and _Spilogale interrupta_ on the other hand, central Texas would be a logical place to collect intergrades. We suppose that such intergradation will be found to occur and that eventually _Spilogale putorius_ will be the specific name to apply to all of the Recent subspecies of spotted skunks. Until proof of such intergradation is forthcoming we employ current nomenclature.

~Spilogale gracilis microdon~ A. H. Howell

A. H. Howell (N. Amer. Fauna, 26:31, November 24, 1906) listed as _Spilogale arizonae martirensis_ one specimen ([Female] sad.-yg., 145886 USBS) from Comondu, which is the type locality of _S.

microdon_. Our examination of [Female] No. 145886 convinces us that it is referable to _S. microdon_.

Examination of the materials used by Howell (_op. cit._) reveals that there is an increase in size of animal and its skull from within the geographic range of _S. g. martirensis_ southward to Cape St. Lucas which is the type locality of _S. lucasana_. Specimens of _S.

microdon_, which so far has been recorded only from Comondu, the type locality, are, as would be expected, intermediate in size between _S.

g. martirensis_ and _S. lucasana_. The differential characters of these three named kinds of _Spilogale_ are princ.i.p.ally those of size, and we can see no characters judged to be of more than subspecific worth. Consequently the named kinds should stand as:

_Spilogale gracilis martirensis_ Elliott;

_Spilogale gracilis microdon_ A. H. Howell;

_Spilogale gracilis lucasana_ Merriam.

~Spilogale gracilis microrhina~ Hall

When Hall (Jour. Mamm., 7:53, February 15, 1926) named as new _Spilogale phenax microrhina_, he did not mention specimens previously recorded by A. H. Howell (N. Amer. Fauna, 26:32, November 24, 1906) as _Spilogale phenax_ from San Bernardino Peak (57026 USBS), La Puerta (99580 USBS), Dulzura (55848, 56173, 56873, 33693/45728, 36291/48656 and 36292/48657) in southern California. On geographic grounds these specimens would be expected to be _S. g. microrhina_ although geographically slightly outside the area that could be delimited by Hall's (_op. cit._) marginal record-stations of occurrence. Our examination of the pertinent specimens reveals that they are _Spilogale gracilis microrhina_. The localities from which the specimens came are, respectively, the northeasternmost, easternmost and southernmost occurrences so far listed for the subspecies.

~Conepatus mesoleucus mearnsi~ Merriam

Examination of the holotypes of _Conepatus filipensis_ Merriam, _Conepatus pediculus_ Merriam, _Conepatus sonoriensis_ Merriam, and _Conepatus mesoleucus mearnsi_ Merriam, and other specimens of the two kinds last named, convinces us that all are the same species and that the names should stand as follows: _Conepatus mesoleucus filipensis_ Merriam (type locality, Cerro San Felipe, Oaxaca); _Conepatus mesoleucus pediculus_ Merriam (Sierra Guadalupe, Coahuila); and _Conepatus mesoleucus sonoriensis_ Merriam (Camoa, Rio Mayo, Sonora).

One method of designating the ages of individuals in _Conepatus_ is to recognize four categories from younger to older, as follows: 1) juvenile--retaining one or more deciduous teeth; 2) young--sutures open and clearly to be seen between bones of the facial part of the skull; 3) subadult--skull of adult form, but lacking sagittal and lambdoidal crests and retaining faint traces of sutures between facial bones; and 4) adult--sutures obliterated, lambdoidal ridge high and temporal ridges (of females) or sagittal crest (of males) prominent.

On this basis of designating age, the holotype of _C. pediculus_ is young and nearer the juvenal than the subadult stage. Its small size is partly the result of its youth. Other than its small size we find no characters to distinguish it from _C. m. mearnsi_. Unfortunately no young male of _C. m. mearnsi_ of the same age as the holotype of _C.

pediculus_ is available. Also, from the general area of the Sierra Guadalupe, Coahuila, only the one specimen of _Conepatus mesoleucus_ (the holotype of _C. m. pediculus_) is known. Consequently, we can not yet prove that some young males of _C. m. mearnsi_ are as small as the holotype of _C. pediculus_. Because of this lack of proof we tentatively recognize the subspecies _Conepatus mesoleucus pediculus_ instead of placing the name _Conepatus pediculus_ in the synonomy of _Conepatus mesoleucus mearnsi_.

The holotype of _C. sonoriensis_ is a young female, older than the holotype of _C. pediculus_, and approximately midway between the juvenal and subadult stages.

The holotype of _C. filipensis_ is an adult male.

We suppose that _C. mesoleucus mesoleucus_ Lichtenstein and _C.

mesoleucus mearnsi_ Merriam on the one hand, and _Conepatus leuconotus leuconotus_ Lichtenstein and _C. l. texensis_ Merriam on the other hand will be found to intergrade, in which event the name _Conepatus leuconotus_, having page priority over _Conepatus mesoleucus_, will apply to the species. Proof of complete intergradation is not yet available. The one difference between the two that prevents our uniting them as subspecies of one species is the larger size of _C. l.

leuconotus_ and _C. l. texensis_. Measurements of the smallest adult male and female available to us of _C. l. texensis_ and of the largest adult male and female of _C. m. mearnsi_ are given below.

Where the geographic ranges of the two species approach one another the only taxonomically significant difference detected by us is in size, _C. leuconotus_ being larger than _C. mesoleucus_. Other characters that are useful in separating the two alleged species now are known to vary geographically in a fas.h.i.+on that indicates only subspecific status for the two kinds. For example, three specimens from Laredo, Texas (previously recorded by V. Bailey, N. Amer. Fauna, 25:205, October 24, 1905--Nos. 24839/32237, 24840/32238 and 24842/32245 USBS), bridge the gap in color pattern between _C. l.

texensis_ to the east and _C. m. mearnsi_ to the west. _C. l.

texensis_ characteristically has the white stripe terminating anteriorly in an obtuse angle, and on the hinder back the area of white is restricted to a narrow line or is wanting. _C. m. mearnsi_ characteristically has the white stripe truncate anteriorly and approximately as broad on the hinder back as on the shoulders. In the specimens from Laredo, the young female, No. 24842, has the white nearly truncate anteriorly (pointed in the other two specimens, adult females). In No. 24839 the area of white on the hinder back is only slightly restricted in width (noticeably restricted but present in the other two specimens).

The proof of intergradation, or the lack of it, between the two alleged species, _Conepatus mearnsi_ and _Conepatus leuconotus_, would seem to be profitably sought by obtaining specimens along the Rio Grande in Texas between the Blocker Ranch ("50 miles southeast of Eagle Pa.s.s") and Laredo.

Measurements ill.u.s.trating the size difference between the two alleged species are as follows:

TABLE 1. Measurements of _Conepatus_ from Texas

Column Heading Legend:

Col. A: [Male] ad. 186455 USNM, Mason, Texas. Type Col. B: [Male] ad. 31970/24575 USBS, Blocker Ranch, Texas Col. C: [Female] ad. 126241 USBS, 8 mi. S Langtry, Texas Col. D: [Male] ad. 47122 USBS, Brownsville, Texas. Type Col. E: [Male] ad. 45132/33129 USBS, Brownsville, Texas Col. F: [Male] yg. 45900/33865 USBS, Brownsville, Texas Col. G: [Female] ad. 47121/34865 USBS, Brownsville, Texas Col. H: [Female] ad. 24839/32237 USBS, Laredo, Texas Col. I: [Female] ad. 24840/32328 USBS, Laredo, Texas Col. J: [Male]? sad. 16651 AMNH, Kingsville, Texas

============================================+========================== C. mesoleucus mearnsi | C. leuconotus texensis ----------+------+------+-----+-----+-----+-----+-----+-----+-----+---- | A | B | C | D | E | F | G | H | I | J ----------+------+------+-----+-----+-----+-----+-----+-----+-----+---- Total | 633 | ... | 610 | 800 | 920 | 770 | 670 | 685 | 700 | ...