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, Río 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 fashion 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).