Abstract The red-legged seriema (Cariama cristata) is unique among extant birds in that they possess prominent recurved sickle claws on the second pedal digits which are held off the ground, outwardly similar to the claws of the extinct deinonychosaurs and basal avialans, and probably convergently evolved due to similar lifestyle/feeding habits. Thus, the way in which seriemas use their claws has the potential to shine additional light on how deinonychosaurs used theirs. Though formerly thought of as slashing weapons, it has also been hypothesized that deinonychosaurs used their claws to pin and grasp rather than slash. This newer hypothesis has been called the Raptor Prey Restraint (RPR) hypothesis. Our observations of claw use in simulated and real feeding behavior of red-legged seriemas at the Wildlife World Zoo, Aquarium, and Safari Park in Phoenix, AZ, and the Tracy Aviary and Botanical Gardens in Salt Lake City, UT, are consistent with the RPR hypothesis. The seriemas were observed using their feet, with special preference given to digit II, to pin objects/prey, which were torn at in tandem with the beak. Given the high degree of similarity between the claws of seriemas and the claws of deinonychosaurs, as well as their shared paravian ancestry and similar predatory cursorial lifestyles, it is likely that seriemas are among the best extant proxies for deinonychosaur claw use. That they use their claws in a manner so consistent with hypothesized deinonychosaur claw use is further evidence that the RPR hypothesis is most likely the best hypothesis for the function of the digit II “killing claws” of deinonychosaurs.
This paper presents a speculative hypothesis that climatic change and the integration of the lower Colorado, Salt, Verde, and Gila rivers led to the development of four of Arizona's dune fields. The Parker and Casino Dune fields have been researched prior; however, the Sedona and Painted Rock Dunes are presented here as two previously unrecognized dune fields. The structure of this paper goes through each of these dune fields to (i) review current knowledge; (ii) present new insight resulting from analyses of previous soil survey mapping work; (iii) speculate on the formation hypothesis for each dune field in more detail; and (iv) detail the sorts of additional work that would test the hypotheses. While no explicit evidence connecting river integration to Arizona dune field formation is presented here, soil data, field observations, aerial imagery, and dune field proximity to integrated river systems suggest further research should be conducted on this topic.
Abstract The upper elevation limit of Cylindropuntia acanthocarpa is often reported as either 1,200 or 1,300 m, despite the type locality being at 1,465 m. We provide 31 herbarium records from over 1,300 m elevation, 23 personal iNaturalist photographic records from 1,700-1,900 m, and evidence that the upper limit of C. acanthocarpa may be 2,000 m.
We monitored the persistence of a remnant population of pronghorn (Antilocapra americana) near Hillside, AZ, over an 11-year period from May 2008 through December 21, 2019. Originally consisting of three bucks, two does, and one female yearling, the last pregnant doe was seen March 13, 2014, and the last fawn was seen on November 10, 2014. Only one buck was seen after June 17, 2014, and no males after July 7, 2018. The last pronghorn seen were three does on a follow-up survey April 3, 2021. Although the possibility exists of animals immigrating or emigrating from the 78 km2 study area, we did not document such behavior during our study. With no overt attempts at management the population doubled, before losing four animals following a May 2014 Palmer Drought Severity Index (PDSI) of -4.09. The persistence of this population through 2021 is attributed to low adult mortality and a greater recruitment of females than males. The low percentage of available habitat utilized suggests an adequate carrying capacity. The disappearance of this population is attributed to inbreeding depression and low recruitment due to genetic bottle-necking. The Hillside population was too small and too isolated to survive without periodic translocations. Although we frequently observed coyotes during our surveys, predation was not considered the principal factor in the population's demise.
The San Pedro Riparian National Conservation Area (SPRNCA) protects approximately 60 linear kilometers (km) of the San Pedro River within the Madrean Sky Islands region of southeastern Arizona. This cottonwood-willow (Populus fremontii-Salix gooddingii) gallery forest habitat with perennial surface flow is unique from the Chihuahuan mesquite desert and supports a wide diversity of plant and animal life. Mountain lions (Puma concolor) were hypothesized to use the SPRNCA as a temporary habitat while moving between neighboring mountain ranges. Using remote camera traps located on desert washes that drain the Huachuca Mountains, we demonstrated that mountain lions use the riparian corridor as part of their resident home range. We recorded 53 independent observations (mean of 1.47 observations per 100 trap nights) of mountain lions with at least 30 minutes between sightings during our study between September 2019 and May 2021. Mountain lions were found using riparian habitat in all seasons and photos were taken of young kittens within 0.3 km of the San Pedro River. Preferred prey species (Coue's white-tailed deer [Odocoileus virginianus couesi] and javelina [Pecari tajacu]) have been observed often within the SPRNCA. Future research should explore the connectivity and metapopulation structure of mountain lions within the SPRNCA and neighboring mountain ranges.
Abstract We summarize >80 accounts of jaguars killed and/or photographed in Arizona during a 160-year period. These accounts include 13 previously unrecorded animals and six contemporary photographic records. The period with most records occurred between 1900 and 1920. Occurrences ranged from Sonoran desertscrub < 1000 m ASL to mixed confer forest at 2,134 m ASL. Every county in Arizona save four had jaguar records and distribution of records indicate a north by northwest movement along montane corridors from the southeastern quarter of the state northwest to the Grand Canyon. Three counties bordering Sonora yielded numerous records over protracted periods, namely Santa Cruz, Cochise, and Pima Counties. The distribution, number of occurrences and records of females and sub-adults before 1920 suggest some animals may have been breeding residents.
In 2008, and subsequent collecting trips, the remains of a partial basal neornithischian were recovered from the Cenomanian Willow Tank Formation of southern Nevada. Bones identified include the proximal femora, a series of vertebrae missing neural arches, several pedal phalanges, fragments of ossified tendons, and some as yet unidentified elements. Size and shape of the femora are consistent with other known basal neornithischians of both orodromine- and thescelosaurine-grade. The round femoral head exhibits a convex anterior side but a concave posterior surface. The neck beneath the head projects proximodorsally at an obtuse angle (∼100°) from the femoral shaft. The greater trochanter sits slightly posterior to and offset from the neck of the femoral head. Anterior and lateral to the greater trochanter is a pointed lesser trochanter. The three-sided lesser trochanter bows slightly posterior toward the greater trochanter. A prominent and deep notch separates the lesser from the greater trochanter and is characteristic of thescelosaurine-grade ornithischians. This deep intertrochanteric notch is absent in the femora of orodromines. A raised but taphonomically truncated base on the posterior femoral diaphysis likely represents the remnants of a pendant fourth trochanter. The vertebrae of the Nevada basal neornithischian are similar to both thescelosaurine- and orodromine-grade morphology. The laterally biconcave vertebrae are asymmetrical in having a boss on the posteroventral end of the centrum. The centra are nearly twice as long as they are tall with the oval articular surfaces, taller than they are wide. Due to the very fragmentary nature of this specimen, parsimonious phylogenetic analysis yields statistically insignificant results. Nevertheless, a few taxonomically important characters, particularly those of the femur, support the hypothesis that this is a thescelosaurine, and a new genus and species, herein referred to as Nevadadromeus schmitti gen. et sp. nov. This would represent the earliest occurrence of thescelosaurines in the fossil record of North America as all other thescelosaurines from the continent date to the Maastrichtian. The geographic position of the Willow Tank Formation depocenter, very proximal to the Sevier highlands of the time, likely experienced some biogeographic insularity from other areas represented by contemporaneous units of western North America, e.g., Mussentuchit Member of the Cedar Mountain Formation of Utah, the Wayan Formation of Idaho, and the Blackleaf Formation of Montana.
More than 60 years of survey and hunt data indicate declining trends in Arizona's desert cottontail (Sylvilagus audubonii) populations. Survey numbers, hunter participation, harvests, and hunt success for this species after 1990 are considerably less than prior to the 1980s. Summer surveys conducted in the 1950s and repeated in 2019 and 2020 showed that populations were not uniform and related to winter precipitation amounts (r2=0.71, p=0.07). Although one population in 2020 was at an historic low, others were as robust as in the 1950s. Although declines in hunter numbers may be due to sociological factors, the reasons for declining trends in cottontail survey numbers and hunt success are more difficult to evaluate. Precipitation amounts and temperature data suggest that population declines might have been caused by increased mortality due to climate change, increases in predator populations, and/or the presence of disease.
Stocking of rare native fishes for conservation purposes is a common practice in the southwestern United States. Monitoring typically occurs after hatchery-reared fish are released to assess post-stocking movement and survival. We conducted a two-year study, in which tow-barge electrofishing and portable, flat-bed passive integrated transponder (PIT) antennas were used to monitor PIT-tagged, hatchery-reared roundtail chub (Gila robusta) following release into the upper Verde River in Arizona. Specifically, our study aimed to compare the performance of PIT antennas and electrofishing in detecting PIT tagged fish released in a small desert river and to examine the behavioral response of hatchery-reared roundtail chub after stocking. In both years, more fish were detected by antenna arrays (84%) than by electrofishing (30%). roundtail chub were significantly more likely to be detected by antennas than electrofishing each year; however, when antenna data were evaluated only during the few days in which electrofishing took place, there was no significant difference (Year 1, p=0.1784; Year 2, p=0.6295) in detection between gear types for the same time interval, suggesting that electrofishing and antennas are equally likely to detect fish during 48-72 hour time frames. Within 72 hours of release, antennas detected 100% of fish that moved upstream and 93.8% of fish that moved downstream from the stocking location. Overall, less than half (45.6% in Year 1; 41.1% in Year 2) of the stocked roundtail chub were detected using both methods in both years. Utilization of both active capture gear (electrofishing) and passive gear (antennae) had advantages over monitoring with a single method. PIT antennae can be especially useful for managers who lack the personnel or time to implement more intensive methods of capture but want to monitor post-stocking movement and survival of stocked fish.
Semi-desert grasslands in the southwestern United States have undergone significant ecological changes as a result of anthropogenic activities beginning in the 1800s. As efforts to restore semi-desert grasslands continue, importance should be placed on understanding the habitat requirements of species, and their relationships with other plants and animals. We examined habitat characteristics of antelope jackrabbits (Lepus alleni Mearns 1890) at Buenos Aires National Wildlife Refuge in south-central Arizona. We examined antelope jackrabbit habitat in relation to endangered Pima pineapple cacti (Coryphantha scheeri Kuntz var. robustispina Schott) and available freshwater sources. Dominant vegetation type and cover were measured at 247 points in antelope jackrabbit home ranges between October 2015 and December 2015. Additionally, we documented the proximity of antelope jackrabbit locations to Pima pineapple cacti and available water sources to determine whether antelope jackrabbits have a spatial relationship with this endangered cactus or water availability.Antelope jackrabbits did not select for habitat based on the vegetation characteristics we measured, proximity to Pima pineapple cacti or based on water availability (P > 0.05).Some jackrabbit species have indicated habitat structure preferences, and while antelope jackrabbits are most commonly associated with tropic-subtropic savannas, our study did not show that antelope jackrabbits select for specific vegetation types or a specific vegetation density, nor native grasses over non-native grasses. Antelope jackrabbits may encounter and eat Pima pineapple cactus opportunistically, as opposed to selecting habitat where Pima pineapple cactus occur. Additionally, antelope jackrabbits did not choose habitat based on the location of freshwater sources which may be because they do not need to drink water to survive and instead get their water needs from their food. Little information exists on how antelope jackrabbits select habitat. This study concluded that there is no relation between vegetation factors previously thought to influence antelope jackrabbit habitat selection and habitat use. Future studies based on larger-scale variables, like topography or predator pressure, may help in understanding the factors that influence how this species uses man-altered landscapes.
The thermal stability of capsaicin and dihydrocapsaicin were investigated by conducting cooking tests where temperature and duration varied. These results were used to calculate the half-life of capsaicin at different temperatures and to obtain sufficient data to describe all the variables in the Arrhenius equation between 100°C and 210°C. In addition, the degradation of capsaicinoids appeared to followed first order kinetics. Degradation rates also increased at higher temperatures as expected. The unknown variables in the Arrhenius equation of frequency factor (A) and activation energy (Ea) were determined for both capsaicin and dihydrocapsaicin. The frequency factor for capsaicin and dihydrocapsaicin were 2.60×109and 1.25×109, respectively. The activation energy for capsaicin and dihydrocapsaicin were 87.2 kJ/mol and 84.0 kJ/mol, respectively. Pepper samples cooked in water had longer half-lives than dry pepper powder, which suggests hydrolysis was not a significant degradation mechanism. These results estimated that less than 30% capsaicinoid degradation occurred in nine typical cooking scenarios.
Abstract Considerable attention has been paid to perennial aridland rivers due to their disproportionate importance both ecologically and socially within aridlands. The Verde River Basin (VRB) is a large aridland watershed in central-northern Arizona. The river is subject to variable surface flow inputs, but its baseflow is sourced from springs. We investigated trends in increasing summer temperature and reduced June baseflow beginning in 1990 and continuing through the present. We discuss the potential impacts on the 965 reported springs in the watershed. Springs of the VRB support a wide array of flora and fauna. Early summer dry-season flows are almost entirely derived from springs making the aquatic species of the VRB almost entirely springs-dependent. VRB baseflow was increasing prior to 1990, with a change in trend that coincides with a change in air temperature. Declining snowpack and infiltration, coupled with warming temperatures since 1990 have reduced baseflow basin-wide through reduced groundwater supply, with likely impacts to springs ecosystems, especially springs fed by “younger” groundwater that is most vulnerable to reduction in aquifer recharge. The empirical results of this study indicate a trend of warming temperature correlated to diminishing groundwater dependent resources; supporting recent hydrological and climate projections for the American Southwest.
Abstract We collected harvest and survey information on ∼800 antelope jackrabbits (Lepus alleni) and 27 black-tailed jackrabbits (L. californicus) from 2009 to 2020. These data indicated that abundance varied annually and that the antelope jackrabbit population in the study area neither increased nor decreased greatly during the 12 years of the study, while black-tailed jackrabbit numbers remained low. The reasons for population changes in antelope jackrabbits appear complex and include variations in recruitment rate that were not positively related to precipitation amounts that could not be used to predict hunter success. Correlation coefficients between antelope jackrabbit hunt success and the numbers of antelope jackrabbits seen on belt transects weakly correlated with an index to bobcat (Lynx rufus) abundance indicating that further understanding of jackrabbit population dynamics will require investigating factors that affect changes in annual survival rate.
Opuntia cespitosa (Cactaceae, previously known under the synonym O. humifusa) is found over eastern North America, yet its populations are very sparse and small despite effective vegetative reproduction. Their edaphic preferences are poorly known, and may limit the distribution and success of the species. Soils were sampled for %O.M. (organic matter), %sand, %silt, %clay, pH, and kg/ha of P, K, Ca, Mg, and Zn in 33 populations over a wide area of eastern North America. Tissue testing was carried out in three populations. Opuntia cespitosa occurs over a wide variety of nutrient conditions and soil textures, including both acidic and alkaline soils, though soil nutrients were generally poor and thin. Populations of the species occurred on soils with very high levels of calcium that could be toxic for other plants, exceeding 20,000 kg/ha in some areas. Plants in these areas also had high Ca tissue levels, also common in desert cacti. Kruskal-Wallis and Spearman′s correlation results suggest that population size was not related to the soil attributes tested, but does indicate that areas mowed by large mowers have larger populations. This may be the result of local vegetative spread of fragments by mowers.
