Geology topics

Ronald M. Nowak

Publications and source records attributed to Ronald M. Nowak.

6 recordsLinked to original sources

USGS2023

A plea for Red Wolf conservation throughout Its recent distribution

Canis rufus (Red Wolf) is one of the most endangered mammals in North America. However, genes of the Red Wolf persist across much of the species' original range, carried predominantly within C. latrans (Coyote) populations. It is now known that such genes are distributed from extreme north-central Texas through most of eastern Texas to southern Louisiana. Publicizing of the most recent findings of Red Wolf genes in Coyotes of southern Louisiana emphasized that area for intensive conservation efforts. Such efforts could be applied throughout the entire known distribution of those rare genes, not just in the small area of southern Louisiana recently publicized. Because conservation efforts might be hindered by local conditions and circumstances, expanding geographic options for their application could make the difference in their success.

Southesatern Naturalist↗

USGS2011

Use of cranial characters in taxonomy of the Minnesota wolf ( Canis sp.)

Minnesota wolves ( Canis sp.) sometimes are reported to have affinity to a small, narrow-skulled eastern form ( Canis lupus lycaon Schreber, 1775) and sometimes to a larger, broader western form ( Canis lupus nubilus Say, 1823). We found that pre-1950 Minnesota wolf skulls were similar in size to those of wolves from southeastern Ontario and smaller than those of western wolves. However, Minnesota wolf skulls during 1970–1976 showed a shift to the larger, western form. Although Minnesota skull measurements after 1976 were unavailable, rostral ratios from 1969 through 1999 were consistent with hybridization between the smaller eastern wolf and the western form. Our findings help resolve the different taxonomic interpretations of Minnesota skull morphology and are consistent with molecular evidence of recent hybridization or intergradation of the two forms of wolves in Minnesota. Together these data indicate that eastern- and western-type wolves historically mixed and hybridized in Minnesota and continue to do so. Our findings are relevant to a recent government proposal to delist wolves from the endangered species list in Minnesota and surrounding states.

Minnesota↗

USGS2010

Systematic status of wild Canis in North-central Texas

Skulls of wild Canis collected 2003–2004 in north-central Texas are morphometrically similar to a series taken there and in nearby areas in 1964–1971, which was considered to represent a population of Coyotes ( C. latrans ) modified through introgression from Red Wolves ( C. rufus ). A few of the new specimens closely resemble small examples of Red Wolves. Such affinity is supported by authoritative examination of living and videotaped animals. The persistence of influence of Red Wolves, long after presumed extirpation through hybridization and human persecution, may be relevant to wolf conservation.

Texas↗

USGS2002

The systematic status of the Italian wolf Canis lupus

In the past, the gray wolf Canis lupus Linnaeus, 1758, has been recognized in Italy as either the subspecies lupus or italicus . It has also been postulated that this population has undergone introgression from the domestic dog Canis familiaris . In order to clarify these issues, multistatistical analyses were made of 10 skull measurements of 34 full grown male wolves from the Italian Peninsula, 91 other male Eurasian wolves, and 20 domestic dogs. The analyses, together with other morphological evidence and prior genetic research, support recognition of the Italian wolf as a separate subspecies, Canis lupus italicus . The same evidence indicates that the subspecies has not been affected through hybridization with the domestic dog.

Acta Theriologica↗

USGS1998

Cranial and dental abnormalities of the endangered red wolf Canis rufus

Three skulls of captive-raised female endangered red wolves ( Canis rufus ) exhibited severe malocclusion of the jaws. Cranial and dental abnormalities (including crowding of upper toothrows, and an extra tooth behind the lower left M3 in one of the three mandibles) were also evident. Ratios of alveolar length of maxillary toothrow to maximum width across the outer sides of crowns of P4 were significantly different (p=0.008) compared to unaffected skulls. Significant differences were also evident when ratios of maximum width across inner edges of alveoli of P1 to alveolar length of maxillary toothrow and maximum width across outer sides of crowns of P4 were compared between the two groups. Although the three skulls all exhibited malocclusion, the abnormality expressed itself differently in relation to the effects to each skull. Captive inbreeding may increase the probability and frequency of expressing these anomalies, although inbreeding coefficients calculated for the wolves expressing malocclusion were not considered high (0.0313-0.0508). A wild female red wolf specimen captured in 1921 in Arkansas also exhibited the malocclusion, although not as severely as in the captive females. This demonstrates that this trait was present in wild populations prior to, and not a result of, the captive breeding program.