PUBLICATIONS OF THE MUSEUM TEXAS TECH UNIVERSITY Two publications of The Museum of Texas Tech University are issued under the auspices of the Dean of The Graduate School and Director of Academic Publications, and in cooperation with the International Center for Arid and Semi-Arid Land Studies. Shorter research papers are published as Occasional Papers, whereas longer contribu¬ tions appear as Special Publications. Both are numbered separately and published on an irregular basis. Institutional libraries interested in exchanging publica¬ tions may obtain the Occasional Papers and Special Publications by addressing the Exchange Librarian, Texas Tech University, Lubbock, Texas 79409. Individuals may purchase separate numbers of the Occasional Papers for $1.00 each from Texas Tech Press, Texas Tech University. Remittance must be enclosed with request. Institutional subscriptions also are available through Texas Tech Press. y OCCASIONAL PAPERS THE MUSEUM MUS. COMP. ZOOl— L.IBRARV harvard ur>iiVE:RSiTY AUG 2 1 1979 TEXAS TECH UNTVERSOA 17 Al’Gl’ST 1979 NUMBER 59 DISTRIBUTIONAL CHECKLIST OF RODENTS IN CANYONLANDS NATIONAL PARK, UTAH David M. Armstrong Students of mammalian distribution have long been fascinated by the CxDlorado Plateau. The Colorado River system gathers its headwaters in the middle and southern Rocky Mountains and flows to the Sea of Cortez. Along most of their lengths, the Colo¬ rado and Green rivers are the only permanent streams and they provide a linear oasis for the dispersal of mesic-adapted species through a vast desert region. Throughout much of their course, however, the rivers lie entrenched in canyons that may extend 5000 feet below the level of the surrounding landscape and doubt¬ lessly form significant barriers to the dispersal of terrestrial ani¬ mals. Grmnell (1914a, 19145) discussed the distribution of birds and mammals along the low'er reaches of the Colorado River in Arizona and California. Goldman (1937) described the influence of the river farther north in Arizona, espx’cially in the \icinity of the Grand Canyon. Hoffmeister (1971) reported on mammals of Grand Canyon National Park, and Ploffmeister and Durham (1971) described mammals of the Arizona Strip, that pait of .Ari¬ zona north and west of the Colorado River. In Utah, majoi studies of the effects of the Colorado and Careen rivers on mam¬ malian distribution were published by Kelson (1951) and Duiiant (1952). Studies by Durrant and Dean (1959, 1960) at river-level have been especially useful. Ben.son (1935) examined the mam¬ mals of Navajo Mountain, and Hayward et al. (1958) described broad patterns of ecological distribution of vertebrates along the upper Colorado River basin. Tanner (1965) reported rodents of 2 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY the uranium-mining districts surrounding Canyonlands National Park. Effects of the rivers farther upstream have been discussed by Armstrong (1972) and Long (1965). An account of the ecological distribution of rodents in Canyonland National Park is in prepa¬ ration. For comments on zoogeographic relationships of mam¬ mals in Utah, see Armstrong (19775). Of particular interest on the Colorado Plateau is the confluence of the Colorado and Green rivers, for the canyons created by these waterways divide southeastern Utah into three disjunct land masses (Fig. 1). The rugged terrain surrounding this area, how¬ ever, makes it virtually inaccessible by land, as evidenced by the inability of both Kelson (1951) and Durrant (1952) to get within 30 miles of the rivers’ junction. Even the early exploratory surveys that provided fundamental knowledge of mammalian distribu¬ tions elsewhere in the West avoided southeastern Utah. Too rough for railroad builders and too precipitous, rocky, and dry for farming, the region was circumvented both by the Railroad Surveys of the 1850’s and the Bureau of Biological Surv'ey in the early 1900’s. Only the uranium rush during the 1950’s opened the Canyonlands section of the Colorado Plateau to exploration and formal survey. The establishment of Canyonlands National Park in 1964 on 450 square miles of canyons and mesas surrounding the confluence has finally opened the area to scientific explora¬ tion. I began an investigation of mammals within the Park dur¬ ing 1971 in order to gather data for a popular faunal account. In the course of this work, several hundred rodent specimens were obtained, which provided detailed distributional information for a hitherto neglected area. Presented herein is a portion of that work — a systematic account of the rodents of Canyonlands National Park with remarks on the effects of the Colorado and Green rivers on species distribution and differentiation. It is my hope that this paper eventually will lead to more detailed, biosystematic study of spe¬ cies in this area, for such work will enhance markedly our under¬ standing of microevolution in rodents. Methods Specimens reported here were obtained in the period 1972 to 1978 and were used to document ecological distribution and to provide information on reproduction and life histories, pelages and molt, ectoparasites, and food habits. This information will be summarized in a handbook of mammals of Canyonlands National Park and vicinity. ARMS I R()N(;— c:hk(;ki.is r of rodfn fs Fig. 1. — Index map of Canyonlands National Park showing ItKalilies frequently mentioned in text. Inset shows location of Oanyonlands National Park in south¬ eastern Utah. Rodents collected by snap and livetrapping were prepared as conventional study skins and skulls. Measurements are only of individuals judged to be adults on the basis of toothwear and fusion of cranial sutures (including the suture between the basitx:- cipital and the basisphenoid). Reproductive maturity, which usu¬ ally precedes morphological maturity, was not deemed a useful criterion of adulthood for present purposes. All measurements reported here are in millimeters: cranial characters, as defined by DeBlase and Martin (1974), were measured by means of dial cali- 4 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY pers read to the nearest 0.1 millimeter. Averages are followed by the range, in parentheses, and values for males precede those for females. External measurements are presented in order as read from museum labels: total length, length of tail vertebrae, length of hind foot, length of ear from notch. Weights of field-caught adults are in grams; females known to have been pregnant are not included. Cranial measurements presented herein are those most frequently reported in systematic work on that taxon, to facilitate comparison with the literature. Specimens examined are listed by administrative district (see Fig. 1): Island in the Sky (San Juan County), Maze (Wayne County), Needles (San Juan County). Within each district, locali¬ ties are recorded from north to south; those occurring at the same latitude are listed westernmost first. Localities were described in ; the field from the map “Canyonlands National Park and Vicin¬ ity, Utah” (1:62,500, U.S. Geological Survey, 1969), and are anno¬ tated with section-township-range. Where localities are in areas not formally surveyed, the Public Land Survey description was interpolated. Elevations, in feet, were estimated from topographic maps with contour intervals of 80 feet. Specimens collected in Canyonlands National Park are deposited in the University of Colorado Museum, The Museum of Texas Tech University, Lub¬ bock, or in a synoptic collection at Park Headquarters, Moab, Utah. I have examined nearly all rodents in the collections of the University of Utah (UU) and Brigham Young University (BYU) from San Juan, Grand, and Wayne counties, Utah, as well as ; many from adjacent counties. Specimens from outside the Park are not listed because most were mentioned by Durrant (1952), | Hayward et al. (1958), or Tanner (1965). The acronyms UU and BYU are noted parenthetically when measurements are given for specimens in either of these collections. Synonymies have been excluded from the species accounts that follow because they have been presented in both Durrant (1952) and Hall and Kelson (1959). Prior publication of a fine key to Utah rodents by Durrant (1952) also made it unnecessary to repro¬ duce that information here. Acknowledgments For help with field work, I thank Charles K. Curlee, S. Scott Panter, William C. Sears, David W. and Peggy Johnson, David Harwood, James G. Owen, and my family, Ann, Jack, and Laura. Michael L. Johnson and James C. Halfpenny have done consider- ARMS I RONC.— CHKC:KL1S I OF RODFN FS 5 able indtpendtnt woik in the Park as ,t^iaduate research assistants, kor access to collections at Brigham Young University, I extend my appreciation to Clyde Pritchett, Hal Black, and C. Lyim Hay- waid, Annie and John VVyckotf made collections at the Lhnv'ersity of LUah available to me. Financial support for various phases of this study has come from the Society of the Sigma XI (1972), the Council on Research and Creative Work of the University of Colorado (1973), the Penrose Fund (Grant No. 7615) of the Amer¬ ican Philosophical Society (1976), and the Colorado State Ihiiversity-National Park Service Cooperative Studies Unit (1977- 1978). Accounts of Species Family Sciuridae Eutamias quadrivittatiis (Say) Colorado Chipmunk The Colorado chipmunk is the smallest, and probably most abundant, sciurid in Canyonlands National Park and occurs in the southern Rocky Mountains as well as on the Colorado Pla¬ teau. These ecologically dissimilar areas each have distinct sub¬ species. The Colorado chipmunk is present in suitable habitat throughout the Park. Seldom are these animals seen far from the cover of broken rock, and often they are found in saxicolous brushlands and in juniper-pinyon woodland. This is the only one of the five chipmunks in Ihah that occurs in Canyonlands. Euta¬ mias minimus, the least chipmunk, inhabits the highlands adja¬ cent to Canyonlands on the east, the Abajo and La Sal mountains and Flk Ridge (Lee, 1960). The Uinta chipmunk, E. umbrmus, occurs in the Henry Mountains (Lee, 1960), and the cliff chip¬ munk, E. dorsalis, is known from VV^ayne County, north of the town of Green River (Durrant, 1952:150). Eutamias quadrivittatus hopiensis Merriam Distribution. — Much of the Colorado Plateau and Uinta Basin, also throughout Canyonlands National Park. Measurements. — Seven males, five females from Island in the Sky: 210.6(207-220), 214.8(206-225); 92.7(84-101), 95.4(90-101); 32.4(31-34), 31.8(31-33); 16.4(15-18), 16.6(15-19); weight, 46.64(42.7- 51.9), 47.48(42.2-55.5). Five males, 12 females from Needles: 212.8(202-221), 220.0(212-227); 92.0(84-94), 94.1(90-100); 33.0(32- 34), 33.2(31-35); 19.0(18-20), 18.3(17-19); weights, 50.80(49.4-54.1), 6 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY 54.97(47.5-71.7). Two males, two females from Maze: 210, 210, 218, 227; 100, 95, 91, 95; 35, 32, 32, 32; 19, 17, 18, 17; weights, 50.4, 52.2, 59.9, 54.1. Representative cranial measurements are presented in Table 1. Remarks. — White (1953) reviewed subspecies of E. quadrwitta- tus, giving measurements of animals from Moab. He stated that there was no evidence of geographic variation across the Green and Colorado rivers, and I concur. Specimens examined (60). — Island in the Sky: head Taylor Canyon, SW ‘4 sec. 15, T. 27 S, R. 19 E, 5600 ft., 1; S of the Neck, N '/j sec. 22, T. 27 S, R. 19 E, 5900 ft., 4; White Rim, sec. 13, T. 27 S, R. 19 E, 4500 ft., 11; mouth Lathrop Canyon, NE ‘4 sec. 13, T. 28 S, R. 19 E, 3950 ft., 2. Maze; Horseshoe Canyon, sec. 7, T. 27 S, R. 16 E, 5200 ft., 4; NE of Hans Flat, SE sec. 21, T. 29 S, R. 26 E, 6400 ft., 1; SW of Elaterite Butte, sec. 16, T. 20 S, R. 17 E, ca. 5200 ft., 1; Teapot Canyon, sec. 12, T. 31 S, R. 16 E, 5440 ft., 2; Waterhole Flat, sec. 13, T. 31 S, R. 16 E, 5600 ft., 2. Needles: NE ‘4 sec. 15, T. 30 S, R. 19 E, 4800 ft., 1; NW ‘4 sec. 20, T. 30 S, R. 20 E, 4840 ft., 1; Splittop Campsite, NE ‘4 NW ^ sec. 29, T. 30 S, R. 20 E, 5015 ft., 2; near Cave Spring, NW ‘4 NE '4 sec. 29, T. 30 S, R. 20 E, 5000 ft., 2; SW of Cave Spring, NW ‘4 sec. 29, T. 30 S, R. 20 E, 5000 ft., 2; NW ‘4 NE '4 sec. 29, T. 30 S, R. 20 E, 5015 ft., 1; NE ‘4 sec. 30, T. 30 S, R. 20 E, 5000 ft., 3; S of Squaw Butte, NW ‘4 sec. 30, T. 30 S, R. 20 E, 5040 ft., 5; Squaw Slot Campsite, NE '^4 SE '4 sec. 25, T. 30 S, R. 19 E, 5000 ft., 3; SE '4 sec. 25, T. 30 S, R. 19 E, 5000 ft., 2; Squaw Canyon, SW ‘4 sec. 36, T. 30 S, R. 19 E, 5200 ft., 4; Joint Trail, NE ‘4 sec. 7, T. 31 S, R. 19 E, 5300 ft., 5; near Fortress Arch, NW ‘4 sec. 28, T. 31 S, R. 20 E, 5440 ft., 1. Ammospermophilus leucums (Merriam) White-tailed Antelope Squirrel The white-tailed antelope squirrel ranges from southeastern Oregon and adjacent Idaho southward through Baja California, occupying deserts of the Great Basin and the Colorado Plateau north and west of the Grand Canyon of the Colorado. In Canyon- lands, this squirrel occurs throughout the Park in suitable habi¬ tat, rocks at the edge of sandy grasslands. They seem less likely to inhabit woodland than chipmunks or rock squirrels. Each district of the Park is occupied by a different nominal subspecies of A. leucurus. Durrant (1952), Hansen (1955), and Kelson (1951) included this species in the genus Citellus. Ammospermophilus leucurus cinnamomeus (Merriam) Distribution. — Southeast of' Colorado River in Utah and adja¬ cent Colorado and Arizona, as well as in Needles District of Canyonlands National Park. Comparisons. — From A. 1. pennipes, A. 1. cinnamomeus differs in darker, more vinaceous color and, generally, slightly larger era- ARMS I RONCi— C'.HECKLIS I OF RODFN FS 7 Table 1. Representative cranial measurements of three species of scturtds. of skull yi -C •J- % z ^ s_z •- -C 5 2 5c £ >-• n; C 2 ^ -5 fe £ c 1 1 i, X *6 j % i - > 3 -S' ^ W > 1 £ •£ X •£ “25 Eutamias quadrivittatus hopiensis, Island in the Skv District Mean, 7 SS 34.18 31.70 18.54 7.66 10.24 18.26 5.64 Minimum 33.3 31.0 18.4 7.2 9.9 17.6 5.5 Maximum 34.9 32.2 18.6 8.3 10.6 18.7 5.8 Mean, 5 $9 34.02 31.80 19.06 8.02 10.30 17.96 5.66 Minimum 33.4 30.9 18.8 7.7 10.0 17.0 5.5 Maximum 34.6 32.4 19.4 8.5 10.6 18.5 5.8 Maze District DMA 2330, (5 34.5 32.5 19.4 8.6 10.4 18.1 5.5 DMA 2340, (5 34.6 32.2 19.2 7.4 10.4 18.4 5.8 Mean, 3 99 34.70 32.47 19.17 8.80 10.4 18.47 5.53 Minimum 34.3 32.2 18.8 8.6 10.0 18.2 5.4 Maximum 35.1 33.0 19.5 9.2 10.8 18.7 5.6 Needles District Mean, 5 SS 34.70 32.38 19.12 8.38 10.38 18.58 5.70 Minimum 33.9 31.6 18.8 7.7 9.6 18.1 5.4 Maximum 35.2 33.2 19.4 8.8 10.9 19.2 5.9 Mean, 12 99 3.5.15 32.55 19.33 8.10 10.38 18.69 5.74 Minimum 34.3 31.6 18.8 7.6 9.8 18.5 5.5 Maximum 36.4 33.7 20.0 8.7 11.2 19.1 6.0 .4mmospennophilus leucurus cinnamomeus. Needles District Mean, 3 SS 40.20 37.60 22.63 10.93 1 1.90 22.23 7.53 Minimum 39.6 36.8 21.5 9.8 1 1.0 21.4 7.4 Maximum 40.8 38.6 23.9 11.7 12.5 22.8 7.8 Mean, 4 99 40.08 37.60 23.52 9.82 1 1,80 22.80 7.22 Minimum 39.7 37.0 23.0 9.0 1 1.1 22.3 7.0 Maximum 41.0 38.1 23.8 10.3 12.5 23.9 7.6 Ammo,spermophilu.s Ieucuru.s notom. Maze District .Mean, 3 99 .39.93 37.50 22.93 9.47 11.76 21,fi0 7..50 .Minimum 39.8 37.1 22.5 9.0 11.2 21.4 7.0 .Maximum 40.2 37.7 23.3 9.9 12.3 22.0 7.8 Ammosj>ermophiIus Ieucuru.s pennipes. Island in the Sky Distric t D.MA 2312, (5 40.6 37.7 24.5 9.0 12.1 22.2 7.3 Mean, 3 99 40.55 38.03 23.43 9.10 1 1.70 22.07 7.5 Minimum 40.1 37.1 23.1 8.8 1 1.5 21.6 7.3 .Maximum 41.0 38.8 24.0 9.5 12.0 23.0 7.8 8 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY Table 1. — Continued. Spermophilus variegatus grammurus Grand and San Juan Counties east of Colorado River (BYU, UU) Mean, 5 $$ 61.27 58.03 38.32 13.98 21.72 36.68 12.20 Minimum 60.8 57.4 37.7 13.1 20.6 36.1 11.5 Maximum 61.7 58.7 39.4 14.4 22.9 37.9 12.8 Mean, 4 99 58.68 55.62 36.70 13.55 21.20 34.78 12.00 Minimum 57.4 54.2 35.4 12.9 20.5 34.2 11.8 Maximum 59.5 56.0 37.9 14.0 21.5 35.2 12.6 nial size (see Remarks). For comparison with A. 1. notom, see account of that subspecies. Measurements. — Three males, four females from Needles: 216.7(215-220), 225.7(220-232); 64.3(60-71), 66.7(60-70); 41.3(40-42), 39.5(39-40); 16.0(14-18), 16.5(15-18); weights, 107.43(93.8-118.5), 117.18(110.9-127.9). Cranial measurements appear in Table 1. Remarks. — According to Howell (1938:175), A. 1. pennipes aver¬ ages slightly larger cranially than A. 1. cinnamomeus. McCoy and Miller (1964) and Armstrong (1972:118) showed A. 1. cinnamo¬ meus in Colorado to be somewhat smaller than A. 1. pennipes. However, in Utah, Durrant (1952:125) pointed out that skulls of A. 1. cinnamomeus generally are larger than those of A. 1. pen¬ nipes. Our few data support Durrant’s observations. Specimens examined (9). — Needles; near Cave Spring, NW '4 NE '4 sec. 29, T. 30 S, R. 20 E, 5000 ft., 1; SW of Cave Spring, NW ‘4 sec. 29, T. 30 S, R. 20 E, 5000 ft., 4; W of Squaw Butte, NE ‘4 sec. 25, T. 30 S, R. 19 E, 5040 ft., 1; NE ‘4 sec. 30, T. 30 S, R. 20 E, 5000 ft., 3. Ammospermophilus leucurus notom (Hansen) Distribution. — San Rafael and Dirty Devil drainages and in the Uinta Basin west of the Green River; known in Canyonlands National Park from the Maze District. Comparisons. — From A. 1. pennipes and A. 1. cinnamomeus, A. 1. notom differs in ’’redder color lacking practically all white and black bands of the hairs, on the head and dorsum”; rostrum pro¬ portionally shorter (Hansen, 1955:275). Measurements. — One male, four females from Maze: 212, 219.2(210-225); 60, 63.0(59-70); 40, 39.5(39-40); 15, 12.2(10-14); weights, 94.6, 103.18(95.1-112.9). Representative cranial measure¬ ments appear in Table 1. Remarks. — When Hansen (1955) named this subspecies, he ascribed to it a range in the “Uinta Basin, west of Green River, San Rafael Swell, lower drainages of the Dirty Devil River in ARMS I RONC;— CHKCkl.lS 1 OK RODF.N I S 9 Emery and Wayne counties, Utah.” He examined specimens from as close to the Maze District as Hanksville. lanner (1965) (on- irasted specimens from rem[)le Mountain (on the San Rafael Swell, Emery County, in the rant^e of A. 1. notom) and the Yel¬ low Cat Mining District (15 mi. SE Thompson’s, Chand County, in the range of A. /. pennipes). He noted that scjuirrels from Temple Mountain had dorsolateral stripes with a pronounced curve or undulation, unlike the straight stripes of CTand County specimens. This distinction is not borne out by our specimens, and I suggest that its presence or absence is at least partly an arti¬ fact of preparatory technique. Specimens examined (5).— Maze; Hans Flat, SE S sec. 29, T. 29 S, R. 16 E. 6560 ft., 1; SVV of Elaterite Butte, sec. 16, T. 30 S, R. 17 E, ca. 5200 ft., 1; Teapot Canyon, sec. 12, T. 31 S, R. 16 E, 5-140 ft., 1; Waterhole Flat, sec. 13, T. 31 S, R. 16 E, 5600 ft., 2. Ammospermophilus leucums pennipes Howell Distribution. — Grand Valley of the Colorado (see Armstrong, 1972:118) and westward into the region between the Colorado and Green rivers; Island in the Sky District of Canyonlands National Park. Comparisons. — See accounts o( A. 1. cinnamomeus and A. 1. notom. Measurements. — One male, three females from Island in the Sky: 223, 219.7(212-229); 69, 60.7(60-61); 40, 40.7(40-42); 13, 15.0(15-15); weights, 112.4, 115.33(107.0-122.5). Five males, 10 females (BYU) from vicinity of Arches National Park: 219.0(210- 227), 209.9(200-220); 60.0(49-65), 62.3(55-71); 39.2(38-40), 38.3(37- 40);-,—; weights, 104.3(86-115), 102.3(84-107). Remarks.— \ am unable to assign with any confidence subspe¬ cific rank to antelof^e ground squirrels from Island in the Sky. When specimens in comparable, fresh pelage are sorted by dorsal color, there are two series: pale, reddish buff animals and darker, vinaceous animals. Animals from the Island appear in both se¬ ries. My uncertainty is not unique. Kelson (1951:33) called A. leu- curus from Grand County north of the Colorado River cinnamomeus, whereas Durrant (1952:124) referred them to pen¬ nipes. Hansen (1955:276) considered this an area of intergradation between A. 1. notom and A. 1. pennipes, and assigned specimens from here to the latter subspecies. I see no consistent cranial dis¬ tinctions in material from the three districts of Canyonlands National Park. In short, populations of antelo^x^ ground squirrels do not seem as distinctive as current nomenclature might lead 10 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY one to imagine. A taxonomic revision of A. leucurus that is based on a thorough understanding of nongeographic as well as geo¬ graphic variation is indicated. Specimens examined (7). — Island in the Sky: Green River, sec. 1., T. 26 S, R. 17 '/2 E, 4000 ft., 1: White Rim, SE '4 sec. 24, T. 27 S, R. 19 E, 4600 ft., 1; NE corner Gray’s Pasture, SW % sec. 22, T. 28 S, R. 19 E, 6000 ft., 2; sec. 5, T. 28 S, R. 19 E, 6050 ft., 2. Spermophilus variegatus (Erxleben) Rock Squirrel The rock squirrel occupies semiarid foothills and mountains from Puebla northward to northern Utah and Colorado. In Canyonlands National Park, the animals seem to be nowhere abundant but can be found in colluvial rubble, often about wood¬ lands, at all elevations. I expect that two subspecies occur in the Park. Spermophilus variegatus grammurus (Say) Distribution. — Southern Utah and adjacent Colorado, south¬ ward through Arizona and New Mexico into Sonora and Chihua¬ hua; Island in the Sky and Needles districts of Canyonlands National Park. Comparison. — From S. v. Utah, S. v. grammurus differs in paler color dorsally (more buffy, less blackish); venter more cinnamon-colored, less white; and skull averaging smaller. Measurements. — Five males and five females from Grand and San Juan counties (UU, BYU): 466.4(438-485), 467.0(445-480); 188.8(155-210), 189.7(175-200); 59.0(55-65), 54.4(51.56); 28.5(26-32), 29.4(25-32). For cranial measurements, see Table 1. Specimens examined (2). — Needles: Squaw Slot Campsite, NE '4 SE '/< sec. 25, T. 30 S, R. 19 E, 5000 ft., 1; NE ‘4 sec. 30, T. 30 S, R. 20 E, 5000 ft., 1. Spermophilus variegatus Utah (Merriam) Distribution. — Central and southwestern Utah, the Arizona Strip, and southern Nevada; of probable occurrence in the Maze District of Canyonlands National Park. Comparison. — See account of S. v. grammurus and Durrant and Hansen (1954). Measurements. — One young male (BYU 4245) from 26 mi. S San Rafael River Bridge, Wayne County: 442, 187, 63, 25; weight, 467. For cranial measurements, see Durrant and Hansen (1954). ARMSTRONC,— CHECKLIS T OF RODENTS Remarks.— KtAson (1951:29) and Dunant (1952:118) rfstriool the use of the name 5'. z'. Utah to specimens Irom akjng the cen¬ tral mountains of lhah. Both authors commented on the diffi¬ culty of identifying to subspecies rock squirrels from lUah, due to broad inteigiadation. Durrant and Hansen (195‘4) reviewed sub¬ species of rock squirrels in lUah and restricted the use of the name grammurus to animals from south and east of the Colorado Rivet. Durrant and Dean (1959:82) remarked that two subspecies of rock squirrel (Kcurred in Glen Canyon, 5. v. Utah on the west side of the Colorado River, and S. i). grammurus on the east. However, only a single specimen (from the east side of the river) was obtained. Canyonlands National Park is a likely place to obtain the specimens that would clarify local distribution of these two subspecies: however, rock squirrels do not seem to lx‘ very abundant in the Park, although they are present in a variety of habitats at all elevations. Family Geomyidae Thomomys botiae (Eydoux and Gervais) Botta’s Pocket Gopher The valley pocket gopher occupies suitable habitat over much of western United States and northern Mexico. Over its range, this species shows complex distributional relationships with other species of Thomomys. In Utah, for example, both Thomomys bottae and T. talpoides occur widely, but at no place are the two species known to be sympatric. T. talpoides occupies the higher mountains of the state (including the La Sals and the Abajos) and T. bottae inhabits lower areas (although it does occur in some mountains of the Great Basin). Durrant (1946) revised the p^ocket gophers of Utah and later (1952) used their distributions to recon¬ struct Pleistocene events in the state. Throughout the West, pocket gophers generally are abundant animals. Yet none was taken in Canyonlands National Park until 1976, when James C. Halfpenny obtained specimens in Chesler Park and adjacent parts of the Netxlles District. Fhe animals still are unknown from the Island in the Sky or Maze districts. Wagner and Workman (1961) obtained no pozket gophers in Dead Horse Point State Park. Thomomys bottae aureus Allen Distribution. — Four Corners area of Utah, Colorado, Arizona, and New Mexico; Needles District of Canyonlands National Park. 12 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY Comparisons. — From T. b. osgoodi, T. b. aureus differs in larger size both externally and cranially, and darker (more red¬ dish, less yellowish buff) color (after Durrant, 1952:216). From T. b. howelli, T. b. aureus differs in paler dorsal color (without a middorsal patch of grayish to blackish hairs) and in cranial details (see Goldman, 1936:152). By comparison with a series of specimens of T. b. aureus from Bedrock, Montrose County, Colo¬ rado, specimens from the Needles were slightly paler dorsally, slightly more grayish yellow and less reddish. Measurements. — Two males, one female: 218, 229, 214; 63, 72, 69; 28, 28, 22; 5, 5, 5; weights, 124, 133.4, 111. Some cranial meas¬ urements of those individuals are: condylobasal length, 38.8, 39.9, 37.0; basilar length, 33.8, 35.0, 32.5; zygomatic breadth, 24.2, 25.1, 23.1; interorbital constriction, 6.8, 7.1, 7.0; mastoid breadth, 19.9, 20.2, 19.1; breadth of rostrum, 9.0, 9.1, 7.8; length of nasals, 13.7, 13.8, 13.1; maxillary toothrow, 8.7, 8.5, 8.3. Specimens examined (3). — Needles: Joint Trail, NE ‘4 sec. 7, T. 31 S, R. 19 E, 5300 ft., 3. Thomomys bottae howelli Goldman Distribution. — Occurs in an area bounded by the Colorado and Green rivers and the Book Cliffs; in Colorado, found along the valleys of tributaries of the Colorado south and east of the river (Armstrong, 1972:153). Comparisons. — From T. b. osgoodi, to which it is quite similar in color, T. b. howelli differs in larger external and cranial size (see Goldman, 1936:116). For comparison with T. b. aureus, see account of that subspecies. Measurements. — Five males, five females from Arches National Park (BYU): 220.0(210-225), 197.2(182-213); 62.0(57-71), 55.2(51- 60); 29.6(28-30), 28.6(27-30); — , — . Representative cranial measure¬ ments include: condylobasal length, 38.80(38.0-40.0), 35.26 (34.8-35.6); basilar length, 34.10(33.2-35.2), 30.64(30.2-31.0); zygo¬ matic breadth, 22.98(22.5-23.9), 21.40(21.0-21.7); interorbital con¬ striction, 6.58(6.3-6.9), 6.56(6.3-6.9); mastoid breadth, 19.94(19.3-20.6), 18.98(18.2-19.6); breadth of rostrum, 8.82(8.4-9.4), 7.88(7.5-8.2); length of nasals, 13.80(12.9-14.7), 11.74(11.2-12.2); maxillary toothrow, 8.04(7.9-8.2), 7.70(7.2-8.2). Remarks. — This is the subspecies to be expected in the Island in the Sky District. Durrant (1952:212) reported specimens from as near the Park as a place 10 mi. N Moab, Grand County. ARMS l RONC;— C’.HtCKLlS 1 OF RODKN FS 13 Thomomys boltae osgoodi Goldniaii Distribution, — East-central lUah, west of the C^oloiado and Cireen rivers, from the Henry Mountains northward to the Book Cdiffs. Comparisons. —Scv accounts of T. b. aureus and T. b. howelli. Remarks. — Ehis is the subspecies to be expected in the Maze District. At present the locality of record nearest the Park is the type locality, Hanksville, Wayne County, Utah. Family Heteromyidae Perognathus apache Merriam Apache Pocket Mouse The Apache pocket mouse inhabits desert grasslands of the Colorado Plateau, with extensions into the Rio Grande Valley and through the Deming Plains of New Mexico into northern Chihuahua. In Canyonlands, the animals occur in abundance on the bunchgrass flats of the Needles and Island in the Sky districts. Perognathus apache caryi Goldman Distribution. — Utah and Colorado, mostly east of the Green River (and east of the Colorado, south of the confluence), and north of the San Juan. Comparison. — P. a. caryi differs from P. a. apache in larger external and cranial size, darker color, and more inflated brain- case (after Durrant, 1952:236). Measurements.— Your males, five females from Needles: 136.8(135-139). 143.6(139-148); 66.0(65-69), 73.2(72-74); 18.8(18-20), 18.0(18-18); 7.0(7-7), 7.0(7-7); weights, 12.60(11.6-13.6), 11.40(10.8- 11.8). Seven males, six females from the Island in the Sky District: 136.6(126-144), 137.8(129-147); 66.3(59-69), 66.5(66-70); 17.7(17-18), 17.5(17-19); 7. 0(6-8). 7.0(7-7); weights, 13.20(9.5-14.8), 13.68(11.2- 16.1). For cranial measurements, see I able 2. Specimens examined (28).— Island in the Sky: Big Flat. set . 21. T. 26 S. R. 19 E. 6000 ft., in Grand Co.. 2; sec. F. 27 S. R. 19 F. 60.50 ft.. 1; flat SF S sec. 10. F. 27 S. R. 19 E. ,5760 ft.. 3; NF corner C^ray’s Pasture. SVV '« sec. 22. F. 27 S. R. 19 F. 6000 ft.. 1; S end C.ray's Pasture, sec. 32. F. 27 S. R. 19 F. .5960 ft.. 7; SW S sc-c. 6. T. 28 S. R. 19 E. 6040 ft.. 1; Willow Flat. SVV S sec . 6. F. 28 S. R, 19 F. 6010 ft.. .3. Needlf-s: 'c mi. SE (ktve Spring. NF S sc‘c . 30. I. .30 S. R. 20 F. .5010 ft.. 1; SW of Cave Spring. NVV S sec. 29. F. 30 S. R. 20 F. .5(K)0 ft.. 2; W of .Sejuaw Butte. NF S sec. 25. T. 30 S. R. 19 F. 5010 ft.. 3; S of .Sejuaw Butte. NVV S sec. .30. F. .30 .S. R. 90 F 'io40 ft 1- NF S sec. 30. T. 30 S. R. 20 F. .5000 ft.. 1; Chesler C'.anyon at Bc-ef Bastn Road ’sE S sec. 7. F. 31 .S. R. 19 F. .5280 ft.. 1. 14 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY Table 2. — Representative cranial measurements of two species of Perognathus. Occipilonasal length Zygomatic breadth Breadth of interparietal Breadth across bullae Length of maxillary toothrow I.ength of nasals Circa test length of skull Perognathus apache caryi. Island in the Sky District Mean, 7 $$ 23.03 12.36 4.51 13.83 3.44 8.64 22.69 Minimum 22.4 11.9 4.1 12.9 3.2 8.3 23.2 Maximum 23.8 12.8 4.8 14.9 3.6 9.2 24.8 Mean, 6 99 23.58 12.42 4.57 13.90 3.57 8.74 24.24 Minimum 22.6 11.6 3.9 13.3 3.4 8.6 23.7 Maximum 24.5 12.7 5.2 14.2 3.7 9.2 24.8 Needles District Mean, 4 $$ 22.68 11.90 4.35 13.22 3.35 8.50 23.58 Minimum 21.8 11.6 4.3 12.5 3.2 7.9 22.6 Maximum 23.3 12.4 4.4 13.9 3.6 9.2 24.2 Mean, 5 99 22.52 11.96 4.24 13.06 3.40 8.58 23.30 Minimum 21.4 11.4 3.9 12.4 3.3 8.1 22.0 Maximum 23.1 12.2 4.5 13.6 3.5 9.0 24.1 Perognathus parvus bullatus. Maze District Mean, 10 $$ 25.10 13.30 4.13 14.70 3.72 9.44 26.09 Minimum 24.4 12.4 3.6 14.0 3.4 9.0 25.2 Maximum 27.5 14.3 4.7 15.3 4.2 10.8 28.5 Mean, 19 99 24.74 13.28 4.19 14.39 3.88 9.30 25.71 Minimum 23.2 12.7 3.3 13.9 3.5 8.6 24.2 Maximum 26.1 14.0 4.8 15.0 4.1 10.5 26.9 Perognathns parvus (Peale) Great Basin Pocket Mouse As the vernacular name implies, this is a species centered on the Great Basin, but it extends into adjacent semidesert areas, in particular the Columbia Plateau, the Snake River Plain, the Wyoming Basin, and the deserts of central Utah. This mouse is known from Canyonlands only from the Maze District, where it is abundant in stands of blackbrush. At Horseshoe Canyon, several individuals were taken in areas of “slickrock” and colluvial rub¬ ble. Hayward and Killpack (1958) described geographic variation and distribution of this species in Utah. Perognathus parvus bullatus Durrant and Lee Distribution. — San Rafael Desert and adjacent areas, probably bounded by the San Rafael, Colorado, Green, and Fremont rivers ARMS I RONC;— CHECIKI.IS 1 OF RODFN I S 15 aiul tht^ highlaiKls of ctMitral Utafi; Ma/.t* District ol C.anyorilands National Park. Comparisons.— ¥oi comparison with otlier named kinds of P. pan'us, see Durrant and Lee (1956) and Hayward and Killpack (1958). Ten males, 19 females: 169.7(164-176), 171.2(158-174); 88.5(85-92), 91.2(85-102); 21.6(21-22), 21.6(20-23); 7. 9(7-8), 7. 5(7-8); weights, 16.48(14.4-20.8), 15.43(13.5-18.4). For cranial measurements, see Table 2. Kemrtr/t5.— Specimens from the Maze are near topotypes of F. p. bullatus] Ekker’s Ranch (Robber’s Roost), the type locality, is adjacent to Canyonlands National Park on the west. Specimens examined (32).— Maze; Horseshoe Oinyoti, sec. 7, T. 27 S, R. 16 E, 5200 ft.. 13; North Point, sec. 36, T. 29 S. R. 16 E, 6^00 ft.. 1; Hans Flat. SE h sec. 29, r. 29 S, R. 16 E, 6560 ft., 1; S\V of Elaterite Butte, sec. 16, E. 30 S, R. 17 E, ca. 5200 ft., 1; Waterhole Flat, sec. 13, T. 31 S, R. 16 E, 5600 ft., 13. Dipodomys ordii Woodhouse Ord’s Kangaroo Rat Ord’s kangaroo rat is the most widespread member of the genus Dipodomys, occurring from the plains of Alberta and Saskatche¬ wan to Hidalgo, and from California to Oklahoma. This is a mammal of grasslands where sandy soils permit extensive burrow systems. Fhe animals are present throughout Canyonlands National Park and often are abundant locally. Setzer (1949) revised subspecies of D. ordiv, two subspecies occur in Canyon¬ lands National Park. Dipodomys ordii nexilis Goldman Southeastern lUah and adjacent Colorado, gen¬ erally north of the San Juan River and southeast of the Colorado; Needles District of Canyonlands National Park. Comparison. — Sct account t)f D. o. sanrafaeli. Measurements. — males, 18 females from Needles: 256.5(241-280), 259.5(236-283); 143.3(132-1.55), 141.4(126-171); 41.8(38-44), 41.8(39-46); 14.3(13-18), 14.4(12-16); weights, (>0.19 (50.8-70.7), 60.1(.50.3-68.0). For cranial measurements, str Fable 3. Another subs{>ecies, D. o. longipes, is found in southeastern Utah south of the San Juan River and east of the Colorado (Durrant and Dean, 1959:87). Setzer (1949:5(50) observed that D. o. nexihs “is apparently not abundant at any place in its range.’’ This certainly is not true in the Needles District. 16 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY Table 3. — Representative cranial measurements of two subspecies of DifKxiomys ordii. Greatest length of skull Basilar length Breadth across bullae Breadth across maxillary arches Interorbiial constriction Length of nasals Length of maxillary toothrow Mean, 17 SS Dipodomys ordii nexilis. Needles District 39.26 24.18 25.16 20.09 12.82 13.86 5.01 Minimum 37.3 23.6 24.1 19.0 12.1 13.1 4.8 Maximum 40.6 25.9 26.0 21.1 14.4 14.6 5.4 Mean, 18 9$ 39.51 24.20 25.49 20.57 12.82 14.04 5.05 Minimum 37.7 23.3 24.3 19.2 11.4 12.9 4.9 Maximum 41.0 25.0 26.4 21.9 13.7 15.0 5.4 Dipodomys ordii sanrafaeli Island in the Sky District and Deadhorse Point State Park (BYLI) Mean, 3 SS 39.47 24.36 25.13 20.57 12.87 14.27 5.10 Minimum 39.2 24.1 24.9 20.0 12.3 14.0 5.1 Maximum 40.0 24.9 25.4 21.0 13.2 14.5 5.1 Mean, 4 99 39.72 24.78 25.42 20.57 12.68 14.22 5.22 Minimum 39.1 24.0 24.9 20.3 12.1 13.7 4.9 Maximum 40.6 26.3 25.8 21.0 13.4 14.7 5.5 Arches National Monument (BYLI) Mean, 1 1 (5(5 39.80 24.51 25.39 20.70 12.98 14.35 5.05 Minimum 38.7 24.0 24.6 19.2 12.1 13.7 4.9 Maximum 40.4 25.1 26.4 21.7 14.2 14.9 5.5 Mean, 6 99 38.12 24.43 25.07 20.53 12.43 14.30 5.08 Minimum 34.9 23.6 24.1 19.6 11.7 13.3 4.9 Maximum 39.9 25.0 26.4 21.5 13.0 15.1 5.3 Maze District Mean, 11 (5(5 38.62 23.78 24.90 20.17 12.38 13.77 4.69 Minimum 37.6 22.9 24.0 19.2 11.4 13.0 4.0 Maximum 39.5 24.5 25.7 20.9 13.5 14.4 5.1 Mean, 6 99 38.55 23.64 24.70 20.35 12.35 13.38 4.95 Minimum 37.5 23.1 24.2 19.8 11.2 13.1 4.8 Maximum 40.1 24.1 25.3 20.8 12.8 14.1 5.3 Specimens examined (79). — Needles: rim SW ‘4 SE ‘4 sec. 10, T. 27 S, R. 19 E, 5600 ft., 1; 7 mi. (by road) N Ranger Station, sec. 18, T. 30 S, R. 19 E, 4940 ft., 3; Salt Creek Wash, NW ‘4 NE ‘4 sec. 20, T. 30 S, R. 20 E, 4950 ft., 1; '4 mi. N Cave Springs Trail, sec. 20, T. 30 S, R. 19 E, 5100 ft., 4; '4 mi. NE Cave Springs Trail, sec. 20, T. 30 S, R. 19 E, 5100 ft., 3; Cave Springs Parking Area, sec. 20, T. 30 S, R. 19 E, 4900 ft., 2; Salt Creek, ‘4 mi. SW Cave Springs Parking Area, sec. 20, T. 30 S, R. 19 E, 4900 ft., 1; Uinta No. 3 Oil Well, NE '4 NW ‘4 sec. 26, T. 30 S, R. 19 E, 5120 ft., 1; Squaw Flat, NE '4 sec. 25, T. 30 S, R. 19 E, 5100 ft., 2; W of Squaw ARMS I RONC;— CIHF.CKI.IS 1 OK RODKN I S 17 Buttf, NF. S str. 25, T. 30 S. R. 19 F. 50-10 li., 1; NF S sec. 30, 1. 30 S, R. 20 F, 5000 ft., 5; SF S str. 25, F. 30 S, R. 19 F, .5(K)0 ft., 1; N\V 5 NF 5 str. 2«>, I . 30 S, R. 20 F, .5015 ft., f; neat Clave Spiiii^^, N\V 5 NF S see. 29, 1 . 30 S, R. 20 F, .5(K)0 ft., 10; NVV >4 NF S see. 29, F. 30 S, R. 20 F, 5015 ft., 1; S mi. SF Clave Sprinf^, NF. S see. 29, F. 30 S, R. 20 K, 5(K)0 ft., 8; .Stpiaw Flat Clampsite, NF S SF S set . 25, F. 30 S, R. 19 K, .50(X) ft., 1; Klephant Hill, SF S S\V S set . 27, F. 30 S, R. 19 F, 5120 ft., 1; Clheslet Cliinytm at Beef Basin Rt)ati, SF S see. 7, F. 31 S, R. 19 F, 5280 ft., 5; Joint I rail, NF S see. 7, I. 31 S, R. 19 F, 5300 ft., 5; Laventlei Cl;myt)n, SF S see. 22, F. 32 S, R. 20 K, 5260 ft., 1. Dipodomys ordii sanrafaeli Durrant and Setzer Distribution. — Maze and Island in the Sky districts and deserts of the Colorado and Green river drainages of east-central Utah and adjacent Cx)lorado. Durrant (1952:261) specified the range as north of the Colorado River in Utah, but in Colorado Armstrong (1972:183) referred to D. o. sanrafaeli animals from the Grand Valley on both sides of the Colorado River. Measurements. — Three males, four females from Island in the Sky and Deadhorse Point (BYU): 247.3(245-250), 255.8(250-268); 138.7(136-140), 143.5(140-152): 42.7(42-43), 42.2(42-43); 14.7(14-15), 14.8(14-15); weights of two females, 66.5, 65.1. Eleven males, six females from Maze: 249.2(241-262), 252.2(240-267): 135.9(130-145), 137.8(131-147); 41.0(39-42), 41.3(40-43); 13.8(13-14), 13.8(13-15); weights, 55.18(49.8-62.7), 53.85(48.2-58.9). Eleven males, six females from Arches National Park (BYU): 255.0(242-270), 250.1(245-258): 139.6(127-150), 139.8(125-150); 42.9(40-45), 41.5(39- 43); — , — . Representative cranial measurements are presented in Table 3. Animals from the Maze District average smaller in all measurements taken than do specimens from the area between the Colorado and Green rivers. This might indicate intergrada¬ tion with D. o. cupidineus, the subspecies to the south. The Maze population has the pale dorsal color of D. o. sanrafaeli, however. Specimens examined (26). — Island in the Sky: SVV SF S see. 10, I. 27 S, R. 19 E, 5600 ft., 1; S end of Ciray’s Pasture, sec. 32, T. 27 S, R. 19 F, 5960 ft., 1; Willow Flat, SVV S sec. 6, T. 28 S, R. 19 F, 6040 ft., 1; Lathrop Canyon, sec. 13, T. 28 S, R. 19 E, 4000 ft., 1. Maze; Horseshoe C^anyon, sec. 7, T. 27 S, R. 16 F, .52(X) ft., 14; North Point, sec. 36, T. 29 S, R. 16 E, 6400 ft., 1; Hans Flat, SF '■» sec. 29, F. 29 S, R. 16 E, 6560 ft., 3; SW of Flaterite Butte, sec. 16, T. .30 S, R. 17 F, c4 sec. 30. T. 30 S, R. 20 E, 5040 ft.. 2; NE sec. 30, T. 30 S. R. 20 E, .5000 ft.. 3; .SW of C;ave .Spring, NW ‘4 sec. 29, T. 30 S, R. 20 E, .5000 ft., 9. Reithrodontomys megalotis megalotis (Baird) Distribution.— Semidnd interior of western North America from British Columbia to Guanajuato, Mexico. In Canyonlands National Park it occurs west of the Cok^rado River. Comparison. — See account of R. m. aztecus. Measurements. — 'Nine males, four females from the vicinity of Arches National Park (BYT): 138.0(130-143), 140.5(137-145); 65.8(61-72), 67.5(65-70); 17.2(15-18), 16.8(15-18);—, — . Repre.senta- tive cranial measurements of five males and four females from the same locality include: greatest length of skull, 21.20(21.0-21.4), 21.10(20.9-21.4); condylobasal length, 19.85(19.6-20.1), 19.60(19.4- 19.9); zygomatic breadth, 10.84(10.5-11.5), 10.93(10.8-11.0); cranial breadth, 10.25(10.2-10.3), 10.30(10.2-10.4); interorbital constriction. 20 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY 3.16(3.1-3.4), 3.18(3.0-3.3); length of maxillary toothrow, 3.44(3.3- 3.5), 3.40(3.2-3.5); depth of skull, 7.94(7.9-8.0), 7.90(7.8-8.1). Remarks. — This subspecies is to be expected, at least at river level, in the Maze District but has not yet been documented there. The single specimen available from the Island in the Sky is a subadult, hence the use of measurements of animals from Arches National Park and vicinity. These measurements generally are slightly smaller than those for R. m. aztecus from the Needles. Kelson (1951:74) referred western harvest mice from both sides of the Colorado River to R. m. megalotis. Specimens examined (1). — Island in the Sky; Green River, sec. 1, T. 26 S, R. 17 ‘4 E, 4000 ft., 1. Peromyscus crinitus (Merriam) Canyon Mouse The canyon mouse is, as its common name suggests, a charac¬ teristic rodent of Canyonlands National Park; perhaps it is the most abundant mammal there. The fact that other species of Peromyscus (P. truei, P. maniculatus) are more abundant in our collections may reflect the fact that the ecologists’ usual predilec¬ tion is for the more complex habitats that provide insight into subtleties of local distribution. Canyon mice are the only mam¬ mals typical of the expanses of slickrock that are the dominant geomorphic feature of much of the Park. Peromyscus crinitus auripectus (Allen) Distribution. — Colorado Plateau and the Uinta Basin, east of the Colorado River; in Canyonlands, it occupies the Island in the Sky and Needles districts. Comparison. — From P. c. doutti, P. c. auripectus differs in slightly richer, more buffy (less yellowish) color, in the usual presence of a reddish buff pectoral spot (see Remarks), and in slightly larger external and cranial size. Measurements. — Five males, three females from Needles: 177.6(171-182), 181.6(180-184); 93.6(90-96), 91.7(90-93); 21.4(20-23), 22.0(22-22); 20.6(20-21), 21.0(20-22); weights, 18.24(16.4-19.6), 17.53(16.4-18.5). Seventeen males, 15 females from Island in the Sky: 175.7(166-185), 178.4(168-185); 92.9(88-100), 94.0(85-98); 21.8(20-22), 20.9(20-22); 21.0(20-22), 21.4(19-22); weights, 17.00(15.0-20.5), 18.61(14.1-22.5). For cranial measurements, see Table 4. ARMS i RONc;— c:nb:c:Ki.is I of rodf.nfs 21 Remarks. — As the siihsjx'citic epithet siii^gests, /■*. c. auripectus is characterizetl by a butty patcti ut tiairs in ttie pectorat region. Sucti a patcti is prominent in 3t ot 33 (93.9 per rent) adutts troin Island in tlie Sky and in nine ol 11 (81.2 per rent) adidts Ironi Needles. Of 16 mice in adult pelage from the Maze District, oidy two have distinct patches; a third individual has an indistinct huffy wash over the entire ventral surface. Specimens examined (71).— Island in the Sky: Ghth Rivt-r, sir. 1, V. 26 S. R. 17 4 E. 4(K)0 ft., 1; Shafo C;anyon, st-c . 7. F. 27 S. R. 20 F, 1100 ft.. 10; SW S st't . 10. T. 27 S. R. 19 E. 5fi00 ft., -1; White Rim, sec. 13. F. 27 S. R. 19 E. IfjOO ft., 3; W of Island in the Sky Headquarters, NW h sec. 15, T. 27 S. R, 19 E, 5900 ft., 1; head Faylor Canyon, SW h sec. 15, V. 27 S, R. 19 E. .5600 ft., 3; S of the Neck, N S sec. 22, r. 27 S, R. 19 E, 5900 ft., 3; rim Shafer C'.anyon, SE h sec. 15, F. 27 S, R, 19 E, 59.50 ft., 2; White Rim, SE h sec. 24, F. 27 S, R. 19 E, 4600 ft., 3; NE corner Ciray’s Pasture, SW h sec. 22, F. 28 S, R. 19 E, (SOOO ft., 1; SW h sec. 36, T. 27 S, R. 18 E, 6000 ft., 1; S of Aztec Butte, sec. 6, F. 28 S, R. 19 E, 6000 ft., 2; sec. 5, T. 28 S, R. 19 E. 6050 ft.. 1; SE h sec. 6, T. 28 S, R. 19 E, 6000 ft., 2; Lathrop Canyon, SE S sec. 12, F. 28 S, R. 19 E. 4000 ft., 3; Lathrcjp Canyon, sec. 13, T. 28 S, R. 19 E, 4000 ft., 4; mouth Lathrop Canyon, NE S sec. 13, T. 28 S, R. 19 E, 39.50 ft., 1. Needles; SW h sec. 34, T. 29 '2 S, R. 19 E, 4800 ft., 6; Big Springs Overlcx^k, NE S sec. 15, T. 30 S, R. 19 E, 4800 ft., 3; NW h sec. 23, T. .30 S, R. 19 E. ;5000 ft., 1; Big .Spring Canyon, NW h sec. 26, 7'. 30 S, R. 19 E, 5100 ft., 1; SW of Cave Spring, NW '4 sec. 29, T. 30 S, R. 20 E, 5000 ft., 3; Squaw Flat Campground, NE h SE h sec. 25, T. 30 S, R. 19 E, 5000 ft., 1; Elephant Hill, SE h SW h sec. 27, T. 30 S, R. 19 E, 5120 ft., 1; .Stxia Springs, .SE h SW h sec. 27, T. 30 S, R. 19 E, 5120 ft., 1; Squaw Canyon, SW h sec. 36, T. 30 S, R. 19 E, 5200 ft., 1; Joint Trail, NE h sec. 7, F. 31 S, R. 19 E, 53(X) ft., 8; Chesler (iinyon, NW S sec. 8, T. 31 S, R. 19 E, 5300 ft., 1; Chesler C'>anyon, SW ‘4 NW ‘4 sec. 8, T. 31 S, R. 19 E, 5350 ft., 2. Peromyscus crinitus doutti Coin Distribution. — Colorado Plateau and the Uinta Basin west of the Colorado and Green rivers. In Canyonlands National Park, it occurs only in the Maze District. Comparisons. — See account of P. c. auripectus. Measurements.— males, six females from Maze: 173.2(170- 177), 173.8(167-180): 91.8(88-94), 92.3(91-95): 21.0(20-22), 21.6(21- 22); 21.0(19-22), 21.4(21-22): weights, 16.04(15.2-17.5), 18.23 (14.9-24.8). Representative cranial measurements appear in Fable 4. Remarks.— \no\hex subspecies, P. c. stephensi, occurs in south- central lUah, to the south of Canyonlands, and northward to Kane CT)unty (Durrant and Dean, 1959:89). Specimens examined (21). — Maze; NE of Hans Flat. SE S set . 21. F, 29 S. R. 16 E, 6400 ft., 3; SW of Elaterite Butte, sec. 16, F. .30 S, R. 17 E. ca. 5200 ft., 5; lea- pot Canyon, sec. 12, I. 31 .S, R. 16 E, 5440 ft., 13. 22 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY Table 4. — Representative cranial measurements of four species of Peromyscus. Greaiesl length of skull Condylobasal length Zygomatic breadth Inierorbiial consiriciion Length of nasals Length of maxillary- toot hrow Depth of skull Peromyscus crinitus auripectus, Island in the Sky District Mean, 17 Sd 24.49 24.03 12.48 4.44 9.62 3.63 8.80 Minimum 25.0 23.3 12.2 4.3 9.1 3.5 8.6 Maximum 25.9 24.8 12.9 4.7 10.0 3.9 9.3 Mean, 15 $9 25.44 23.79 12.47 4.46 9.68 3.64 8.79 Minimum 24.6 23.0 12.2 4.3 9.1 3.5 8.4 Maximum 26.2 24.8 12.7 4.8 10.1 3.8 9.3 Needles District Mean, 5 SS 25.44 24.36 12.66 4.60 9.70 3.74 8.90 Minimum 24.8 23.0 12.3 4.5 9.1 3.6 8.7 Maximum 25.9 24.4 13.0 4.8 10.1 3.8 9.1 Mean, 3 $9 25.53 24.46 12.50 4.53 9.33 3.67 8.73 Minimum 25.3 23.6 12.5 4.5 8.6 3.6 8.6 Maximum 25.8 24.2 12.5 4.6 9.9 3.8 8.9 Peromyscus crinitus doutii. Maze District Mean, 7 SS 24.97 23.37 12.58 4.50 9.49 3.h3 8.71 Minimum 24.5 22.8 12.2 4.3 8.8 3.5 8.6 Maximum 25.4 23.6 13.0 4.7 10.2 3.8 9.0 Mean, 5 99 25.05 23.32 12.30 4.35 9.44 3.64 8.78 Minimum 24.7 23.0 12.0 4.1 8.9 3.6 8.7 Maximum 25.5 23.8 12.7 4.5 10.0 3.8 9.0 Peromyscus maniculatus nebrascensis. Island in the Sky District Mean, 14 SS 24.90 23.60 12.54 3.86 9.78 3.73 9.09 Minimum 24.1 22.8 12.0 3.8 8.5 3.5 8.6 Maximum 25.7 24.5 13.2 4.1 10.3 4.1 9.7 Mean, 19 99 25.19 23.88 12.52 4.01 10.35 3.74 9.09 Minimum 24.5 23.3 11.7 3.8 9.0 3.5 8.7 Maximum 26.2 24.8 13.2 4.5 10.8 4.0 9.4 Peromyscus maniculatus rufinus. Needles District Mean, 15 SS 25.56 24.12 12.71 3.99 10.29 3.87 9.23 Minimum 24.3 23.0 12.2 3.7 9.1 3.7 8.9 Maximum 26.6 25.3 13.2 4.2 10.9 4.1 9.8 Mean, 18 99 25.92 24.59 12.75 4.08 10.59 3.80 9.14 Minimum 24.6 23.2 12.1 3.9 9.6 3.6 8.7 Maximum 26.9 25.6 13.8 4.3 11.2 4.0 9.4 Peromyscus maniculatus sonoriensis. Maze District Mean, 9 SS 24.94 23.88 12.65 3.93 10.03 3.76 9.03 Minimum 23.9 23.2 12.0 3.7 9.3 3.5 8.7 Maximum 25.8 24.4 13.7 4.1 10.6 4.0 9.3 ARMsi RONc;— c:hec:ki.is 1 or rodfms I ablk -1. — C.ontinued. Mean, 6 99 2b. 61 24.45 12.98 3.98 10.45 3.75 9.34 Minimum 2i.l 23.0 12.1 3.8 9.5 3.5 9.1 Maximum 27.0 25.6 13.5 4.1 11.3 4.1 9.8 Peroniystus boylii rowleyi. Island in the Sky District Mean, t $$ 27.40 26.05 13.43 4.45 10.52 4.40 9.68 Minimum 27.2 25.4 13.3 4.4 9.9 4.2 9.4 Maximum 27.7 26.4 13.5 4.6 11.1 4.5 9.9 DMA 23(K). 9 28.5 27.2 14.5 4.1 11.2 4.3 9.9 Ntrdles District Mean. 15 $S 27.70 26.14 13.52 4.37 10.65 4.44 9.59 Minimum 26.7 25.2 13.0 4.0 9.8 4.2 9.1 Maximum 28.5 28.2 14.2 4.7 11.4 4.8 10.2 Mean, 15 99 27.84 26.16 13.58 4.51 10.83 4.37 9.61 Minimum 26.7 25.2 13.2 4.3 10.0 4.1 8.9 Maximum 28.7 26.7 14.0 4.8 11.5 4.6 10.1 Peromyscus truei truei. Island in the Sky District Mean. 16 $$ 28.32 26.63 13.59 4.44 10.79 4.33 10.17 Minimum 27.4 25.7 13.1 4.3 10.1 4.1 9.8 Maximum 28.8 27.7 14.0 4.7 11.3 4.6 10.4 Mean, 1 1 99 28.60 26.96 13.76 4.43 10.99 4.32 10.05 Minimum 27.7 26.1 13.2 4.3 10.2 4.2 9.7 Maximum 30.0 28.0 14.3 4.5 11.7 4.5 10.7 Maze District .Mean, 8 $$ 28.02 26.61 13.48 4.54 10.88 4.42 10.16 Minimum 27.3 25.1 13.1 4.3 9.9 4.3 9.8 .Maximum 28.9 23.0 14.4 4.7 12.0 4.6 10.4 .Mean, 8 99 28.06 26.31 13.66 4.51 10.72 4.35 10.62 .Minimum 26.5 25.3 13.2 4.3 10.0 4.1 9.6 .Maximum 29.6 28.1 14.4 4.9 11.6 4.5 10.6 Nt^xlles District .Mean, 21 SS 27.84 26.17 13.36 4.46 10.64 4.25 10.12 .Minimum 27.1 24.9 12.7 4.2 9.9 4.0 9.8 Maximum 28.7 26.4 13.7 4.8 11.3 4.6 10.5 Mean, 17 99 28.1 1 26.37 13.37 4.45 10.76 4.24 10.01 .Minimum 27.7 24.9 12.5 4.1 10.0 3.9 9.4 Maximum 29.6 27.9 14.1 4.9 11.6 4.5 10.4 Peromyscus maniculatus (Wagner) Deer Mouse The deer mouse is nearly ubiquitous in North America. Ixdng absent only in the Southeast, Alaska, and Arctic Canada. The ani¬ mals are especially abundant in Canyonlands National Park in areas disturbed by man, directly or indirectly, or by geologic 24 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY catastrophe. It answers well to the definition of “weed,” an opportunistic occupant of ephemeral habitats, and this characteri¬ zation is hardly unique to Canyonlands (see, for example, Arm¬ strong, 1977a). Peromyscus maniculatus nebrascensis (Coues) Distribution. — Western part of the Great Plains, from Texas Panhandle to southern Alberta and Saskatchewan, and in the Wyoming and Uinta basins; Island in the Sky District in Canyonlands. Comparisons. — From P. m. rufinus, P. m. nebrascensis differs in slightly smaller average cranial and external size, paler color, middorsum with less pronounced blackish wash, and a pelage that is less reddish overall. From P. m. sonoriensis, P. m. nebras¬ censis differs in slightly smaller size, both externally and cran- ially, and in more brownish (less grayish) dorsal color. Measurements. — Fourteen males, 19 females from Island in the Sky: 158.0(151-169), 161.1(153-175); 70.1(65-79), 68.7(62-15); 20.0(19-21), 19.9(18-21); 17.6(17-19), 17.7(17-20); weights, 18.91(16.5-24.0), 20.51(15.2-29.0, N=\2). For cranial measure¬ ments, see Table 4. Remarks. — See account of P. m. sonoriensis. Specimens examined (38). — Island in the Sky: Big Flat, sec. 21, T. 26 S, R. 19 E, 6000 ft., in Grand Co., 10; Green River, sec. 1, T. 26 S, R. 17 E, 4000 ft., 7; White Rim, sec. 3, T. 27 S, R. 20 E, 4500 ft., 1; junction Shafer Trail and main road, NE ‘4 sec. 10, T. 27 S, R. 19 E, 5700 ft., 1; flat, SE ‘4 sec. 10, T. 27 S, R. 19 E, 5760 ft., 1; W of Island in the Sky Headquarters, NW ‘4 NW‘4 sec. 15, T. 27 S, R. 19 E, 5900 ft., 6; head Taylor Ganyon, SW '4 sec. 15, T. 27 S, R. 19 E, 5600 ft., 1; N of Island in the Sky Headquarters, SW ‘4 sec. 15, T. 27 S, R. 19 E, 5900 ft., 1; W side Gray’s Pasture, W sec. 22, T. 27 S, R. 19 E, 6000 ft., 1; S of the Neck, N sec. 22, T. 27 N, R. 19 E, 5900 ft., 2; NE corner Gray’s Pasture, SW ‘4 sec. 22, T. 27 S, R. 19 E, 6000 ft., 3; S end Gray’s Pasture, sec. 32, T. 27 S, R. 19 E, 5960 ft., 1; Willow Flat, SW '4 sec. 6, T. 28 S, R. 19 E, 6040 ft., 1; mouth Lathrop Canyon, NE ‘4 sec. 13, T. 28 S, R. 19 E, 3950 ft., 1. Peromyscus maniculatus rufinus (Merriam) Distribution. — Southern Rocky Mountains and on the Colo¬ rado Plateau, from north-central Colorado southward to southern New Mexico and Arizona; Needles District in Canyonlands National Park. Comparisons. — From P. m. sonoriensis, P. m. rufinus differs in darker, more reddish color, and larger average external and cra¬ nial size (except zygomatic breadth, which is about the same or ARMS iRONc;— c;hf.(:klis I of rodf.nfs 25 smaller). For comparison with P. m. nebrascensis, see atxount ol that subspecies. Measurements. — Fifteen males, 19 female's from Net'clles: 162.0(156-177), 169.4(154-184): 70.3(57-81), 73.2(65-84); 20.7(19-22), 20.2(19-23): 18.7(17-21), 18.8(17-24); weights, 21.80(17.3-24.7), 24.40(20.0-34.5, iV=13). For representative cranial measurements, see Fable 4. Remarks. — See account of F. rn. sonoriensis. Specimens examined (67). — Nf.kdi.f.s; SVV S sec. 3 t, F. 29 S, R. 19 F, -180() ft., 2; 0.7 nii. N Ranger Station, sec. 18, F. 30 S. R. 19 K, 1910 ft., 1; Salt Oeek Wash, NW h NF *4 scT. 20, F. 30 S, R. 20 F, 1950 ft., 1; NF S sec. 30, F. 30 S, R. 20 F, 5000 ft., 11; SW of C.ave Sfjring, NW \ sec. 29, T. 30 S, R. 20 F, .5000 ft., 20; Splittop Campsite, NF S NW S .sec. 29, F. 30 S, R. 20 F, 5015 ft., 1; NW S NF S sec. 29, T. 30 S, R. 20 F., 5015 ft., 8; SF of Cave Spring, NF S sec. 29, T. 30 S, R. 20 F, .5000 ft., 1; S mi. SF Cave Spring, NF S sec. 29, T. 30 S, R. 20 F. 5000 ft., 7; S of Squaw Butte, NW S sec. 30, T. 30 S, R. 20 F, 5040 ft., 1; sec. 20, F. 30 S, R. 19 F, 5100 ft., 2; Chesler Canyon at Beef Basin Road, SF S sec. 7, T. 31 S, R. 19 F, 5280 ft., 1; Virginia Park, NF S SW S sec. 9, T. 31 S, R. 19 F, .5600 ft., 2; near Fortress Arch, NW' '4 sec. 28, T. 31 S, R. 20 F, 5440 ft., 4; L^ivender Canyon, SF '4 sec. 22, T. 32 S, R. 20 F, 5620 ft., 2. Peromyscus maniculatus sonoriensis (Le Conte) Distribution. — Great Basin as well as Colorado Plateau west of the Colorado and Green rivers; Maze District in Canyonlands National Park. Comparisons. — See accounts of P. m. nebrascensis and F. m. rufin us. Measurements. — Nine males, six females from Maze: 159.2(146- 172), 164.2(152-181); 71.2(65-80), 74.8(69-89); 20.1(18-21), 20.5(20- 21): 17.8(17-18), 18.0(16-20): weights, 20.09(14.7-22.0), 21.02 (16.4-23.2). For representative cranial measurements, see Table 4. Remarks.— Durrani and Dean (1959:90-91) thought that ani¬ mals from Glen Canyon on both sides of the Colorado River were of this subspecies, restricting use of the name F. m. rufinus in San Juan Ciounty to animals from higher elevations. This differs from the usage of Kelson (1951:80) and Durrant (1952:308), who both considered the Colorado River north of the San Juan as a barrier between F. rn. sonoriensis and F. rn. rufinus. The subspecies of F. maniculatus in the area are distiicguished Ix'st by dorsal color. To alh)w objective comparison of color of study skins, a method suggested by Anderson (1956:87) was used. Mice from all three districts were pooled and a range of dor.sal color (adult pelage) from pale to quite dark was noted. One of the paler skins (but not the palest— a specimen from the Island in 26 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY the Sky, DMA 1 147) was arbitrarily assigned the number 2. One of the darker mice (but not the darkest — a specimen from the Needles District, DMA 1662) was assigned the number 4. With these two specimens as standards, skins were scored for darkness of dorsal color on a scale of 1 to 5. Mean scores, followed by range and sample size, for animals from each district were: Island in the Sky, 1.7 (1-3, N=33), Needles, 2.8 (2-5, N=33), Maze, 1.6 (1-4, A^=14). I am inclined to agree with the earler interpretation and assign¬ ment of names as regards animals from Canyonlands National Park. It is true that “deer mice from this region are exceedingly difficult to assign to subspecies’’ (Durrant and Dean, 1959:90), but specimens from the Needles District do average slightly larger in size and darker in color than those from the Maze. Most animals from the Needles District are neither as dark nor as reddish as are deer mice from the highlands of southeastern Utah. However, P. m. rufinus is highly variable in color throughout its range; the local population also is variable, but tends toward the paler end of the variability within this subspecies. This clearly is a case in which traditional skin and skull taxon¬ omy provides inadequate insight into relationships between pop¬ ulations. A thorough biosystematic study of this situation is needed. Specimens examined (19). — Maze: Horseshoe Canyon, sec. 7, T. 27 S, R. 16 E, 5200 ft., 2: North Point, sec. 36, T. 29 S, R. 16 E, 6400 ft., 2; NE of Hans Flat, SE '4 sec. 21, T. 29 S, R. 16 E, 6400 ft., 4; Waterhole Flat, sec. 13, T. 31 S, R. 16 E, 5600 ft., 10. Per omy sens boy Hi (Baird) Brush Mouse The brush mouse occurs in southwestern and south-central United States southward through central Mexico to Nicaragua and El Salvador. The common name is appropriate for in Canyonlands National Park this species usually is found under the cover of dense brush — afforded by oak (Quercus), Mahonia, and even exotic saltcedar (Tamarix). Distribution here and throughout much of its range is patchy, and this probably is the least abundant species of Peromyscus in Canyonlands. Two sub¬ species are expected to occur here, although only one has been documented to date. ARMS I RONG— CUKCKLIS I OF RODF.N FS 27 Peroynyscus boylii rowleyi (Alltn) Distfibution. Soutliward from tht* Clolorado Plateau and southern Hish Plains to central Mexico; Needles and Island in the Sky districts in Qmyonlands National Park. CoTupdrisoti. — See account of P. b. utahejisis. Measurements.— Vimi males, one female from Island in the Sky: 197.8(186-202), 209; 102.2(95-108), 107: 22.2(21-23), 23; 20.2(18-22), 20; weights, 24.00(22.6-25.5), — . Fourtc^en males, 14 females from Needles: 198.2(185-214), 200.8(185-216); 100.8(88- 111), 102.3(87-121); 22.5(22-24), 22.3(21-24); 21.1(19-24), 20.9(19- 22); weights, 26.22(20.6-30.5), 24.64(19.5-30.1, N=l). For representative cranial measurements, see Table 4. Specimens examined (62).— Island in the Sky: Green River, sec. 1, \ . 26 S. R. 17 *2 E, 1000 ft., 2; head Taylor Canyon, SVV S sec. 15, T. 27 S, R. 19 E, 5600 ft., 1; mouth l.athrop Canyon, NE S sec. 13, T. 28 S, R. 19 E, 3950 ft., 5; Lathrop Canyon, sec. 13, T. 28 S, R. 19 E, 4000 ft., 1. Needles: NVV \ NVV S sec. 29, T. 30 S, R. 20 E, 5015 ft., 1; Splittop Campsite, NE 'i NVV ‘i sec. 29, T. 30 S, R. 20 E, 5015 ft., 31; SVV of Cave Spring, NVV S sec. 29, T. 30 S, R. 20 E, 5000 ft., 8; NVV S NE *4 sec. 29, 1. 30 S, R. 20 E, 5015 ft., 12; ^4 mi. VVSVV Ranger Residence .Vrea, sec. 36, T. 30 S, R. 19 E, 5000 ft., 1; .Sc]uavv Canyon, SVV S sec. 36, T 30 S, R. 19 E, 5200 ft., 3; near Fortress Arch, NVV '4 sec. 28, F. 31 S, R. 20 E, 5440 ft., 4; Lavender Canyon, SE ‘4 sec. 22, T. 32 S, R. 20 E, 5620 ft., 12. Peromyscus boylii utahensis Durrant Distribution. — Central Utah at moderate elevations on both sides of the Wasatch Mountains and high plateaus; of probable occurrence in the Maze District, Canyonlands National Park. Comparison. — From P. b. rowleyi, P. b. utahensis differs in smaller external size, relatively longer tail, darker dorsal color, and generally larger cranial size (see Durrant, 1952:317-318). Remarks. — P. boylii is as yet undex^umented in the Maze Dis¬ trict but probably occurs there, especially at river-level. Durrant and Dean (1959:91) rejxjrted several specimens of P. b. utahensis from the west side of the Colorado River in Glen Canyon, north¬ ward to River Mile 148 above Lee’s Ferry (near Ticabook Crt'ek). Specimens from that area were clearly referable to the distinctive subspecies P. b. utahensis. Peromyscus truei (Shufeldt) Piiion Mouse The pihon mouse occupies semide.sert woodlands from south¬ ern Oregon to Oaxaca in Mexico. Perhaps a more appropriate 28 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY common name for this species would be “juniper mouse,’’ for juniper seems to be profoundly important to its natural history (see Douglas, 1969). Pihon mice are abundant throughout Canyonlands National Park, not only in well-developed pygmy- conifer woodland but also in stands of big sagebrush; it also is a common “house mouse’’ about settlements of Park Service per¬ sonnel (who show a distinct predilection for the woodland habi¬ tats in the mosaic of desert ecosystems). Peromyscus truei truei (Shufeldt) Distribution. — Colorado Plateau northward into the Uinta Basin and eastward into the foothills of the southern Rocky Mountains of southeastern Colorado. P. t. truei is found in all three districts of Canyonlands National Park; no other subspecies are recognized in the region. Measurements. — Sixteen males, 11 females from Island in the Sky: 185.5(174-192), 191.6(178-199); 92.5(87-96), 94.1(85-102); 22.8(22-24), 23.1(22-25); 26.5(25-58), 26.4(25-28); weights, 23.6(18.2- 27.2), 25.7(22.7-31.2, N=\Q). Twenty-one males, 18 females from Needles: 189.6(172-201), 190.4(174-215); 92.6(80-105), 93.2(80-104); 23.0(22-24), 23.1(22-25); 25.9(23-28), 25.8(23-28); weights, 22.5(18.2- 26.6), 26.2(19.6-25.7, N=^\0). Eight males, eight females from Maze: 183.9(174-195), 188.0(169-211); 92.4(85-101), 93.7(85-100); 22.2(22-23), 22.4(22-24); 26.0(25-28), 26.1(24-29); weights, 21.48(18.5-24.6), 24.7(17.8-28.5, N=3). Table 4 presents some cra¬ nial measurements. Specimens examined (167). — Island in the Sky; Big Flat, sec. 21, T. 26 S, R. 19 E, 6000 ft., in Grand Co., 9; Green River, sec. 1, T. 26 S, R. 17 H E, 4000 ft., 3; junction Shafer Trail and Main Road, NE '4 sec. 10, T. 27 S, R. 19 E, 5700 ft., 2; Island in the Sky Headquarters, NW ‘4 sec. 15, T. 27 S, R. 19 E, 6000 ft., 1; dome W side Gray’s Pasture, W 'A sec. 22, T. 27 S, R. 19 E, 6000 ft., 2; S of the Neck, N !4 sec. 22, T. 27 S, R. 19 E, 5900 ft., 4; NE corner Gray’s Pasture, SW '4 sec. 22, T. 27 S, R. 19 E, 6000 ft., 2; h mi. S Upheaval Dome, NW '4 sec. 26, T. 27 S, R. 18 E, 5520 ft., 2; SW '4 SE '4 sec. 10, T. 27 S, R. 19 E, 5600 ft., 4; sec. 5, T. 28 S, R. 19 E, 6050 ft., 3; Willow Flat, SW '4 sec. 6, T. 28 S, R. 19 E, 6040 ft., 3; SE ‘4 sec. 6, T. 28 S, R. 19 E, 6000 ft., 3; H mi. N Grandview Point, sec. 32, T. 26 S, R. 19 E, 6000 ft., 1. Maze: North Point, sec. 36, T. 29 S, R. 16 E, 6400 ft., 6; NE of Hans Flat, SE ‘4 sec. 21, T. 29 S, R. 16 E, 6400 ft., 2; Hans Flat, SE '4 sec. 29, T. 29 S, R. 16 E, 6560 ft., 10; SW of Elaterite Butte, sec. 16, T. 30 S, R. 17 E, ca. 5200 ft., 1; Teapot Canyon, sec. 12, T. 31 S, R. 16 E, 5440 ft., 3; Waterhole Flat, sec. 13, T. 31 S, R. 16 E, 5600 ft., 7. Needles: SW ‘4 sec. 34, T. 29 H S, R. 19 E, 4800 ft., 1; 0.7 mi. N Ranger Station, sec. 18, T. 30 S, R. 19 E, 4940 ft., 1; Salt Creek Wash, NW ’4 NE ‘4 sec. 20, T. 30 S, R. 20 E, 4950 ft., 1; 'A mi. N Cave Spring Trail, sec. 20, T. 30 S, R. 19 E, 5100 ft., 1; NW '4 sec. 23, T. 30 S, R. 19 E, 5100 ft., 2; Squaw Flat, SE ‘4 sec. 19, T. 30 S, R. 19 E, 5000 ft., 3; Uinta No. 3 Oil Well, NW ‘4 sec. 26, T. 30 S, R. ARMS I RONC.— C'.UKCKI.IS I OF RODF.N FS 19 E. 5120 It.. 1; Big Spring Canyon. NVV sa. 20. F. 50 S. R. 19 F. 5 KM) li.. 1; W of Scpiavv Bultf, NE sec. 25. F. 50 S. R. 19 E. 5010 fi.. 5; S ol .Scjuaw Butte. N\V S sec. 50. r. 50 S. R. 20 E. 50-10 ft., 8; NE sec. 50. F. 50 S. R. 20 E, .50(M) (t., 19; SW of Ciive Spring, N\V sec. 29, T. 50 S. R. 20 E, 50(K) ft., 2; S[)littop Ciainpsite, NE NE sec. 29. T. 50 S. R. 20 E, .5015 ft., 2; N\V NE 5 sec. 29, 1 . 50 S, R. 20 E. .5015 ft., 1; near C-tve Spring. NVV >4 .sec. 29, F. 50 S. R. 20 E, 5000 ft.. 5; S of C:ave Spring. NE *4 sec. 29. T. 50 S, R. 20 E, .5000 ft.. 1; >4 mi. SE Cave Spring, NE '4 sec. 29, r. 50 S. R. 20 E. .5000 ft., 2; Big Spring Canyon, NVV '4 sec. 26. F. 50 S. R. 19 E. 5100 ft.. -4; rocks N of .Sciuavv Spring, NE 5 SW S sec. 25. T. 50 S, R. 19 E. 5120 ft., 2; .Scpiaw Slot Campsite, NE '4 SE '4 sec. 25, T. 50 S, R. 19 E, 5000 ft.. 5; Park Well, SE S sec. 25, T. 50 S. R. 29 E. .5000 ft., 1; Elephant Hill, SE 5 SW h sec. 27, T. 50 S. R. 19 E, 5120 ft.. 2; SE h sec. 25. F. 50 S, R. 19 E, .5000 ft.. 6; Scptaw Canyon, SE S sec. 25, T. 50 S, R. 19 E, 5100 ft., 2; S of .Squaw Spring, NVV '4 sec. 56, r. 50 S, R. 20 E, 5040 ft., 1; ’4 mi. VV'SVV Ranger Residence Area, sec. 56, r. 50 S, R. 19 E, 5000 ft., 1; Squaw Canyon. SW '/< sec. 56, F. 50 S, R. 19 E, 5200 ft., 6; Chesler C>anyon at Beef Basin Road, SE '4 sec. 7, T. 51 S, R. 19 E. 5250 ft., 1; Joint Trail, N sec. 7, F. 51 S, R. 19 E, 5500 ft., 5; Chesler Canyon, NW h sec. 8, T. 51 S, R. 19 E, 5500 ft., 5; Virginia Park, NE ‘4 SW '4 sec. 9, T. 51 S, R. 19 E, .5600 ft., 1. Onychomys leucogaster (Wied-Neuwied) Northern Grasshopper Mouse The northern grasshopper mouse is a species most common in grassland and shrub-steppe habitats, ranging from Saskatchewan to Tamaulipas and from Oregon to Minnesota. It is an abundant rodent locally in Canyonlands National Park, especially on areas that formerly were grazed heavily. It is surprising that the species has yet to be taken in the district of Island in the Sky; Wagner and Workman (1961) rejxjrted no specimens from Deadhorse Point State Park. Two subspecies are present in Canyonlands. Onychomys leucogaster melanophrys Merriam Distribution. — Central valleys of Utah southward to the Ari¬ zona Strip. In Canyonlands National Park it occurs in the Maze District. Comparison. — Prom O. 1. pallescens, O. 1. melanophrys differs in shorter hind foot, slightly darker color, zygomatic arches more flared posteriorly, braincase narrower and shallower, maxillary toothrow shorter, infraorbital foramen relatively narrow, more slitlike (after Durrant, 1952:328— see Remarks). Measurements. — Specimens of adults from the Maze District are unavailable. Two males, one female (UU) from Ekker’s RoblxT’s Roost Ranch, adjacent to the Park on the west: 150, 137, 146; 38, 35, 40; 22, 20, 20; 18, 13, 16. Representative cranial measurements of two males are: greatest length of skull, 28.5, 28.0; condylobasal 30 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY length, 27.3, 26.6; zygomatic breadth, — , 15.1; interorbital con¬ striction, 5.0, 4.6; length of nasals, 11.0, 11.0; length of maxillary toothrow, 4.8, 4.6; depth of skull, 10.4, 9.8. Remarks. — Unfortunately, all specimens available from the Maze District are subadults so it is impossible to compare meas¬ urements with populations of adults from other districts. None¬ theless, when subadults from the Maze are compared with those from Needles, the cranial distinctions noted by Durrant (1952:328), and indicated above under Comparisons, hold true. In addition to those characters, the occiput of individuals from Maze is slightly broader. These cranial differences support the recogni¬ tion of two subspecies in the Park, O. /. pallescens in Needles (and probably Island in the Sky), and O. /. melanophrys in Maze. Hollister (1914:444) thought the two names synonymous; Benson (1935:451) revived the use of the name pallescens. Specimens examined (8). — Maze: Horseshoe Canyon, sec. 7, T. 27 S, R. 16 E, 5200 ft., 8. Onychomys leucogaster pallescens Merriam Distribution. — Colorado Plateau, occupying adjacent parts of Utah, Colorado, Arizona, and New Mexico. O. 1. pallescens occurs in the Needles District (and probably Island in the Sky). Comparison. — See account of O. 1. melanophrys. Measurements. — Five males, two females from Needles: 156.4(152-165), 161, 160; 46.2(41-50), 51, 46; 22.4(20-24), 23, 23; 19.4(18-22), 19, 19; weights, 36.65(34.0-40.4), — . Representative cranial measurements of these animals include: greatest length of skull, 28.85(28.4-29.5), 28.5, 28.3; condylobasal length, 27.70(27.2- 28.3), 26.8, 27.5; zygomatic breadth, 14.75(14.3-15.4), 14.5, 14.7; interorbital constriction, 5.14(5.0-5.3), 5.2, 5.2; length of nasals, 11.42(10.8-11.8), 11.2, 11.1; length of maxillary toothrow, 4.76(4.7- 4.8), 4.8, 4.7; depth of skull, 10.50(10.4-10.7), 10.4, 11.0. Three males, three females from localities in Grand County north of Moab (north and west of the Colorado River, UU): 148.3(142-160), 151.3(150-153); 42.3(40-45), 42.7(42-44); 22.0(22-22), 21.3(20-22); 18.0(17-19), 18.3(18-19). Cranial measurements of three females: greatest length of skull, 28.37(28.0-29.0); condylobasal length, 27.75(26.9-28.6); zygomatic breadth, 14.65(14.4-14.9); interorbital constriction, 4.80(4.8-4.8); length of nasals, 10.80(10.3-11.3); length of maxillary toothrow, 4.60(4.6-4.6); depth of skull, 9.80(9.7-9.9). Specimens examined (42). — Needles: Big Springs Waterhole, NE h sec. 15, T. 30 S, R. 19 E, 4800 ft., 1; NW '4 sec. 14, T. 30 S, R. 19 E, 4960 ft., 1; Salt Creek Wash, ARMS I RONC;— CHF.CKLIS I OK RODKN I S SI NVN S NVV S sec. 20, I. HO S. R. 20 K, 1950 It., I; S ol .St set. 29, K. HO S, R. 20 E, .5(K)0 ft., 5; Chesler C;anyon at Beef Basin Road, SE S sec. 7, K. Hi S, R. 19 E, .5280 ft., I. Neotoma lepida Thomas Desert Woodrat Neotoma lepida ranges over much of the Colorado Plateau, Great Basin, and Sonoran deserts. In Canyonlands National Park, the animals live in a variety of habitats from woodlands and piles of rubble on slickrock rims to colluvium on riverbanks. This may be the most abundant woodrat in the Park, although the collec¬ tor’s bias against the rather monotonous habitats it often occupies has resulted in only modest sample sizes. Neotoma lepida sanrafaeli Kelson Distribution. — From western Colorado southward to Garfield County, Utah; Maze and Island in the Sky districts of Canyon- lands National Park. Measurements. — Five males, one female from Island in the Sky; 278.8(274-285), 282; 119.2(112-126), 121; 31.6(31-33), 30; 29.8(29- 31), 29: weights, 118.96(105.5-132.2), 138.8. Eight females (UU) from the vicinity of Ekker’s Robber’s Roost Ranch (adjacent to Maze on the west): 273.1(260-300); 116.6(110-137); 27.1(23-30); 30.5(28-34). Eor cranial measurements, see Table 5. Remarks. — A smaller and darker subspecies, N. 1. monstrabilis, occurs to the south of Canyonlands, but all specimens from the Park are referable to N. 1. sanrafaeli. Desert woodrats exist only north and west of the Colorado River, insofar as is known. Specimens examined (26). — Maze; Horseshoe Ciinyon, set . 7, 1 . 27 S, R. 16 E, 5200 ft., 3; North Point, sec. 36, T. 29 S, R. 16 E, 6400 ft., 1; Keapot Canyon, sec. 12, T. 31 S, R. 16 E, 5440 ft., 2; VVaterhole Elat, sec. 13, T. 31 S, R. 16 E, .5600 ft., 3. IsLA.ND IN THE .Sky: junction .Shafer Krail and main road, NE \ sec. 10, K. 27 S, R. 19 E, 5700 ft., 1; SE \ SE S sec. 10, T. 27 S, R. 19 E, .5600 ft., 2; Shafer C-myon, sec. 7, T. 27 S, R. 20 E, 4I(K) ft., 2; White Rim, sec. 13, K. 27 S, R. 19 E, 4.5(X) ft., 1; dome W side Gray’s Pasture, W sec. 22, T. 27 S, R. 19 E, 6(KXf ft., 1; White Rim, SE sec. 24, T. 27 S, R. 19 E, 4.500 ft., 1; NE ''i sec. .32, T. 27 S, R. 19 E, 6000 ft., 2; SW sec. 36, T. 27 S, R. 18 E, 6000 ft., 1; SE \ sec. 10, T. 27 S, R. 19 E, 5600 ft., 2; Lathrop Canyon, SE .sec. 12, T. 28 S, R. 19 E, 4000 ft., 2; mouth Lathrop C>anyon, NE '4 sec. 13, T. 28 S, R. 19 E, 39.50 ft., 3; S mi. N Grandview Point, sec. 32, T. 28 S, R. 19 E, 6000 ft., 1. 32 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY Table 5. — Representative cranial measurements of four species of Neotoma. CxHidylobasal length Basilar length Zygomatic breadth Inierorbiial constriction Length of nasals Breadth of rostrum l.ength of maxillary t(X)throw Depth of skull Neotoma lepida sanrafaeli. Island in the Sky District Mean, 5 (Jd 37.16 31.78 20.10 5.12 14.04 5.80 8.38 14.20 Minimum 35.6 30.1 18.7 4.7 13.9 5.4 8.1 13.6 Maximum 38.5 33.0 20.7 5.3 14.2 6.4 8.8 14.6 DMA 1071, 9 38.2 32.8 20.2 5.2 13.2 6.0 8.1 14.3 Maze District and Vicinity DMA 2385, S 38.2 32.5 19.8 4.9 14.9 5.7 8.5 14.4 Mean, 8 9$ 37.00 31.59 19.52 4.75 13.84 5.66 8.29 14.13 Minimum 36.4 31.0 19.1 4.5 13.3 5.4 8.0 13.9 Maximum 38.2 32.8 19.8 5.0 14.8 6.0 8.5 14.4 Neotoma albigula laplataensis, Needles District DMA 1501, 9 41.4 35.3 21.8 5.7 16.3 7.2 7.4 15.5 DMA 1561, 9 44.5 37.8 23.9 5.6 17.2 7.4 8.1 16.1 Neotoma mexicana inopinata. Needles District Mean, 12 99 41.52 35.02 21.58 5.17 17.10 6.58 9.03 14.73 Minimum 39.3 32.8 20.0 4.9 15.9 6.1 8.5 14.4 Maximum 43.2 37.0 22.4 5.6 18.9 7.2 9.3 15.2 DMA 1354, S 41.0 34.7 22.5 5.5 17.3 7.3 8.9 14.6 DMA 1607, S 44.1 37.8 22.6 4.9 18.5 6.9 8.8 15.9 Neotoma cinerea ari zonae. Island in the Sky District DMA 1160, S 42.1 36.5 23.1 5.4 17.1 6.8 9.0 15.7 DMA 1227, 9 38.8 32.6 20.8 5.5 15.4 6.5 8.8 Needles District DMA 1403, S 45.7 38.9 24.1 5.2 19.1 6.8 9.1 15.5 DMA 1350, 9 39.4 33.7 21.2 5.7 16.1 6.2 8.8 15.0 Neotoma albigula Hartley White-throated Woodrat The white-throated woodrat ranges from central Mexico north¬ ward to southern Utah and Colorado. In the northern reaches of its distribution, the species occurs mostly in woodland habitats on rough, broken terrain. Two subspecies range near Canyon- lands National Park, but only one has been documented within the Park boundaries, and this was in the Needles District. ARMS I RONC;— CIHF.CKLIS I OF RODFN FS Neotoma albigula laplataensis Miller Comparison. — Prom N. a. breincauda, N. a. laplataensis clilfers in smaller external and cranial size and relatively longer tail and hindf(K)t. Measurements.— One female maintained in captivity: 277, 127, 27, 29. P'or cranial measurements, see Table 5. Remarks. — N. a. breincauda was named by Durrant (1934) from Castle Valley, 15 mi. NE Moab, Grand County, Ibah, which is on the east side of the Colorado River. This subspecies is found alsc:) in adjacent parts of Colorado in the Dolores-San Miguel drainage (Armstrong, 1972:220). N. a. laplataensis was named from the San Juan drainage c^f Colorado and is known from sev¬ eral localities in San Juan County, lUah, of which the nearest to Canyonlands National Park was a place 12 mi. N Blanding (Dur¬ rant, 1952:336). Durrant and Dean (1959:93) reported this subspe¬ cies from river miles 78 and 69 (above Lee’s Ferry) in Glen Canyon. Specimens examined (3). — Needles: C^ve Spring, NVV S SF ''i sec. 20, T. 30 S, R. 20 F, 5000 ft., 1; SF S sec. 25, T. 30 S, R. 19 F, 5000 ft., 1; SE of Cave Spring, \F sec. 29, T. 30 S, R. 20 E, 5000 ft., 1. Neotoma mexicana Baird Mexican Woodrat The Mexican woodrat occurs from Nicaragua northward through much of Mexico to Colorado and LJtah. The animals are particularly abundant abemt rimrock in areas of saxicoline brush. N. mexicana is known only from the Needles District in Canyon- lands National Park, where it is often taken among rtxks in oakhrush- M a honia thickets along with Peromy.scus boy hi. Neotoma mexicana inopinata Cjoldman [distribution. — Four C. Mj/,. .V = l() .V=I7 Fsland in the Sky 0. 138 0.515 0.937 0.909 Maze 7 0.182 15 0.818 Needles 9 3 15 H Studies in Canyonlands National Park allow a better understand¬ ing of the relationships among these areas. In some respects these studies suggest stronger faunal affinities among the isolated piec¬ es of southeastern lUah than one might have supposed, given the nature of the barriers to free dispersal in the area. Table 6 is a list of rodents known or expected to occur in the three districts of Canyonlands National Park. Species generally are present in at least two of the three districts, with the excep¬ tion of Perognathus pan>us, which is restricted to Maze, and ;Veo- toma albigula and N. mexicana, which occur only in Needles. As a result of the wide-ranging distributions for species, faunal sim¬ ilarity between districts is high, as shown in Table 7. The index for similarity used here is S = 2 C / Nx + N2, where C is the number of species or subspecies common to two areas and N x and N2 are the total numbers present in each of the areas under com¬ parison. At the specific level, the strongest resemblance exists between Island in the Sky and Maze; the weakest, between Maze and Needles. Based on a comparison of subspecies, each district harbors a more distinctive fauna, as shown by reduced S values, and the pattern of district relationships shifts; Island in the Sky is now more like Needles than Maze, but Maze and Needles still maintain the greatest degree of difference. Using the same index and considering all mammals (not just rodents) at the specific level, Armstrong (1977/d calculated sim¬ ilarity between the CTand Valley (Island in the Sky) and San Rafael (Maze) subcenters at over 0.9.50 and mean similarity of approximately 0.900 between those two sulx enters (plus tlu Kai- parowits subcenter) and sulxenters east of the C-olorado River (San Juan— the Netxlles District— plus Navajo Mountain and Monument Valley). 40 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY I would hesitate, in a zoogeographic analysis, to put too much emphasis on subspecies unless they are quite well marked, and many of the supspecies of the Canyonlands are not. However, some patterns of subspecific differences deserve attention. Only three subspecies are common to all three districts; Castor canadensis repentinus (to which the rivers obviously provide no barrier), Eutamias quadrivittatus hopiensis, and Peromyscus truei truei. The latter two are widespread subspecies of abundant and euryecious species and have similar habitat requirements (Arm¬ strong, in press). The Maze and Needles districts have no other subspecies in common whereas Island in the Sky and Maze share four additional ones: Dipodomys ordii sanrafaeli, Reithrodont- omys megalotis megalotis, Neotoma lepida sanrafaeli, and Ere- thizon dorsatum epixanthum. These subspecies show no ecologic “common denominator” but rather they differ widely in ecologi¬ cal distribution. The Island in the Sky and Needles districts have six additional subspecies in common: Perognathus apache caryi, Onychomys leucogaster pallescens, Spermophilus variegatus grammurus, Peromyscus crinitus auripectus, Peromyscus boy hi rowleyi, and Neotoma cinerea arizonae. The first tw'o species occupy grassland; the latter four are saxicolous. There are three species with different nominal subspecies in each district: Ammospermophilus leucurus, Thomomys bottae, and Peromyscus maniculatus. I consider the subspecies of A. leu¬ curus, a denizen of the ecotone between grassland and saxicoline habitats, to be poorly delineated. T. bottae is a fossorial species with readily identifiable subspecies, tied firmly to friable soils. P. maniculatus is a euryecious species, adaptable to a wide range of habitats, with well-marked subspecies in the area. The faunas of the three districts differ little with respect to areographic faunal elements represented (see Table 6). Also I see no particular pattern in the ecological distribution of those spe¬ cies that do or do not show subspecific differentiation across the rivers, except that the two terrestrial rodents that show no dis¬ cernible variation in the Park, Peromyscus truei and Eutamias quadrivittatus, are those found by Armstrong (in press) to be the most euryecious. At the specific level, the faunas are not very distinctive. The two species that characterize the Needles District, Neotoma albig- ula and N. mexicana, seem to occur in the more mesic saxicoline habitats (see Armstrong, in press). Such habitat restriction would serve to localize these species in Needles even in the absence of barriers to dispersal. The one species limited in the Park to the ARMS I RONC;— C'.HF.CKl.IS I OF RODFN FS •11 Mazt Distiict is Perogriathus pan>us, a species ol .c^rasslaiuls and shiub stepjx*. I he C»reat Basin pcx ket mouse is not known to (xcui east of tfie C»reen River even alx)vc* Flaininj^ Ciort^c' in scxithwestern Wyoming (Long, 1965:617). Dm rant and Dean (1960.221) pointcxl out that it is rather fx*rplexing to understand how this river, which treezes solidly in winter and [practically dries up again in summer, can function as such a complete bar¬ rier to extension of ranges by” Ferognathus pawns and F. fasciatus. Both Durrant (1952) and Kelson (1951) observed that the Colo¬ rado River system forms a progressively weaker barrier north¬ ward. The pattern of distribution of rodent species in Canyonlands National Park supports this contention. Of subspe¬ cies held in common by the Needles and Island in the Sky dis¬ tricts, all but Feromyscus boylii rowleyi are kncpwn to range into Colorado above Grand Junction (Armstrong, 1972). Tlius, they may have crossed (or may be crossing) the river barrier well above the canyons. Similarly, species present in both Island in the Sky and the Maze all occur north at least to the town of Green River. Durrant (1952) pointed out that the Green River sometimes freezes over at Jensen and Ouray. The Colorado River near Grand Junction at low water is a braided stream, replete with islands and sandbars. Few species whose ecological tolerance allows access to the river’s banks should find it an impassable barrier. At drier times in the past, the Hypsithermal Interval, for example, flows of both rivers must have been reduced and the ultimate bar¬ rier would have been weakened. Flowever, only the most drought- adapted species would have had access to the barrier across desert floodplains or through the colluvium at the bases of canyon walls. In Canyonlands National Park itself, the ultimate distribu¬ tional barriers, the rivers, must be quite effective. Their flow is perennial, abundant, and they do not freeze. Among rodents, only the beaver can use the rivers as a corridor and can cross with little difficulty. Riparian vegetation is highly discontinuous in the canyons and provides no dis[)ersal route for associated s[x'cies (for example, F. boylii, R. rnegalotis), although j)hotogra[)hs of the canyons taken in the early 1870s and re[)licated a tentury later (see Baars and Molenaar, 1971) suggest that riparian vegetation is more nearly continuous today than it once was. For most s[)ecies throughout most of the Park, the actual barriers to distributic^n must be ecological. Well developed pinyon-juniper wocxiland does not occur at river level in the Park and neither does grass- 42 OCCASIONAL PAPERS MUSEUM TEXAS TECH UNIVERSITY land. Only the most euryecious mammals of saxicoline brush- lands have ready access to the rivers and a potential corridor along them. Given the substantial barriers that exist, it is somewhat surpris¬ ing that the subspecies of rodents in the Canyonlands are not more different. Genetic communication among populations of terrestrial rodents in the three districts must be highly indirect. Are the observed similarities the result of gene flow or of selec¬ tion? These are questions that only biosystematic study can help to resolve. Literature Cited Anderson, S. 1956. Subspeciation in the meadow mouse, Microtus pennsyl- vanicus, in Wyoming, Colorado, and adjacent areas. Univ. Kansas Publ., Mus. Nat. Hist., 9:405-414. Armstrong, D. M. 1972. Distribution of mammals in Colorado. Monogr., llniv. Kansas Mus. Nat. Hist., 3:x-|-l-415. Armstrong, D. M. 1977a. Ecological distribution of small mammals in the Upper Williams Fork Basin, Grand County, Colorado. Southwestern Nat., 22:289-304. - . \911b. Distributional patterns of mammals in Utah. Great Basin Nat., 37:457-474. - . In press. Ecological distribution of mammals in Canyonlands National Park, Utah. Great Basin Nat., vol. 39. Baars, D. L., and C. M. Molenaar. 1971. Geology of Canyonlands and Cataract Canyon. Sixth Field Conference, Four Corners Geol. Soc., iv-l-99 pp. Benson, S. B. 1935. A biological reconnaissance of Navajo Mountain, EUah. llniv. California Publ. Zool., 40:439-455. Brazell, R. E., G. W. Workman, and D. D. May. 1977. A preliminary survey on beaver (Castor canadensis) in Canyonlands National Park, Utah. Processed report. National Park Service, v+38 pp. DeBlase, a. F., and R. E. Martin. 1974. A manual of mammalogy. William C. Brown, Dubuque, Iowa, xv+329 pp. Dice, L. R. 1943. The biotic provinces of North America. Univ. Michigan Press, Ann Arbor, viii+78 pp. Douglas, C. 1969. Comparative ecology of pinyon mice and deer mice in Mesa Verde National Park, Colorado. Univ. Kansas Publ., Mus. Nat. Hist., 18:421-504. Durrant, S. D. 1934. A new wood rat from southeastern Utah. J. Mamm., 15:65-67. - . 1946. The pocket gophers (genus Thomomys) of Utah. Univ. Kansas Publ., Mus. Nat. Hist., 1:1-82. - . 1952. Mammals of Utah, taxonomy and distribution. Univ. Kansas Publ., Mus. Nat. Hist., 6:1-549. Durrant, S. D., and H. S. Crane. 1948. Three new beavers from Utah. Univ. Kansas Publ., Mus. Nat. Hist., 1:407-417. ARMS I RONC;— CHECKI.IS I OF RODFM S Vi Dl'rrant, S. D., and N. k. Dfan. 1959. Mammals ol (.Icn (iimyon. An- ihropol. Papers. Univ. I'tah. 10:73-106. . 1960. Mammals ol Flaming (ioige Reservoir Basin. Anthroix)!. Papers. I’niv. I’tah. 98:209-235. Durrani. S. D.. and R. M. Hanskn. 1959. A new ro