Big Bend National Research Articles

Divergent, plausible, and relevant climate futures for near- and long-term resource planning

Scenario planning has emerged as a widely used planning process for resource management in situations of consequential, irreducible uncertainty. Because it explicitly incorporates uncertainty, scenario planning is regularly employed in climate change adaptation. An early and essential step in developing scenarios is identifying “climate futures”—descriptions of the physical attributes of plausible future climates that could occur at a specific place and time. Divergent climate futures that describe the broadest possible range of plausible conditions support information needs of decision makers, including understanding the spectrum of potential resource responses to climate change, developing strategies robust to that range, avoiding highly consequential surprises, and averting maladaptation. Here, we discuss three approaches for generating climate futures: a Representative Concentration Pathway (RCP)-ensemble, a quadrant-average, and an individual-projection approach. All are designed to capture relevant uncertainty, but they differ in utility for different applications, complexity, and effort required to implement. Using an application from Big Bend National Park as an example of numerous similar efforts to develop climate futures for National Park Service applications over the past decade, we compare these approaches, focusing on their ability to capture among-projection divergence during early-, mid-, and late-twenty-first century periods to align with near-, mid-, and long-term planning efforts. The quadrant-average approach and especially the individual-projection approach captured a broader range of plausible future conditions than the RCP-ensemble approach, particularly in the near term. Therefore, the individual-projection approach supports decision makers seeking to understand the broadest potential characterization of future conditions. We discuss tradeoffs associated with different climate future approaches and highlight suitable applications.

RETRACTED ARTICLE: A new azhdarchoid pterosaur from the Late Cretaceous Javelina Formation of Texas

A historic specimen described for the first time revealed important autapomorphic characters, permitting the definition of a new species, Javelinadactylus sagebieli gen. n. et sp. n., which represents the second toothless species from the Javelina Formation, Big Bend National Park of West Texas (United States of America). The remains of J. sagebieli (Azhdarchoidea: Tapejaridae) were found in 1986, but were never properly studied, and its taxonomic affinity remains undefined. The description is based on a partially articulated skull and mandible, which offer information on the anatomy of a single azhdarchoid pterosaur. J. sagebieli exhibit a large nasoantorbital fenestra, a rostral index of medium value and is assigned to the clade Thalassodrominae, a group of tapejarid pterosaurs that were reported exclusively from the Romualdo Formation of Brazil, with only two genera known. Thalassodromines are characterized by a typical cranial configuration with toothless jaws and a high and wide premaxilla bar, formed by sub-parallel or parallel borders. The new specimen described here represents the first record of the Tapejaridae group in the Maastrichtian of North America, and the cranial morphology of the new taxon increase the richest of the diversity of the azhdarchoid pterosaurs during the end of the Late Cretaceous, suggesting that the tapejarids were still diversifying in the Maastrichtian.

Long-term survival and flowering of ocotillo (Fouquieria splendens) in Texas: A 33-year perspective

Perennial plants of desert regions can be categorized as short-, moderate-, or long-lived. For long-lived species, the typical range of adult life spans is often poorly known, as well as how reproductive effort is apportioned across years. Ocotillo (Fouquieria splendens), a large shrub of the Chihuahuan and Sonoran Deserts, is considered long-lived and flowers spectacularly, but few data exist on these aspects of its life history. In Big Bend National Park, Texas, I marked 140 mature ocotillos in 1986–1988 at 8 sites and measured inflorescence production. In 1990, 2003, 2018, and 2019, I again measured flower output and determined fates of 95 plants which could be relocated, 64% of which survived the 33-year interval. Smaller plants survived better than larger ones. With an annual survival probability of 0.986, the median plant entering adulthood was projected to live 51 more years. All plants flowered in each study year unless buds froze; means ranged from 8 to 60 inflorescences (approximately 680–5200 flowers) per plant per site. Most survivors made more inflorescences in 2018–19 than 29–33 years earlier. Thus, an average ocotillo produces large crops of flowers for approximately 50 years, an appropriate strategy if seedlings rarely survive.

The Coryphantha sneedii Complex is Indeed Complex and Continuously Intergrades with Coryphantha vivipara

The Coryphantha sneedii complex is a confusing assemblage of the following intergrading or ill-defined varieties: orcuttii, organensis, sandbergii, villardii, albicolumnaria, leei, guadalupensis, sneedii, and possibly other undescribed taxa. These varieties comprise a continuum of morphological forms, many with overlapping or proximate distributions, and with some morphological variability possibly arising from phenotypic plasticity to the point that the various variety names are not warranted. There is also debate about geographic range of varieties, e.g. is the type variety actually found in Carlsbad Caverns National Park, Big Bend National Park, and Bishop's Cap. Not only is it impossible to consistently distinguish individual plants of the different varieties of Coryphantha sneedii (Britton & Rose) A. Berger, but it is also sometimes impossible to distinguish them from the sympatric Coryphantha vivipara (Nuttall) Britton & Rose, especially from C. vivipara var. neomexicana (Engelmann) Backeberg. Coryphantha vivipara and C. sneedii are distinguishable from all other species of Coryphantha by their 0.5–1.0 mm diameter lenticular druses and usually (but not always) having green fruits/pericarpels, but these two species with overlapping distributions are not always clearly distinguishable from one another. I therefore propose subsuming the entire Coryphantha sneedii complex as a single variety of C. vivipara.

A new pycnodont specimen (Actinopterygii: Pycnodontiformes) from the Upper Cretaceous of Big Bend National Park, Texas, USA, confirming the bony fish genus Macropycnodon as a junior synonym of Acrotemnus

Pycnodonts are an extinct group of bony fishes with crushing dentitions suited to feed on shelled macroinvertebrates. In this paper, we describe a partial skeleton of a large pycnodont collected from the middle Turonian portion of the Boquillas Formation within Big Bend National Park in Brewster County, Texas, USA. The specimen that includes the vomerine and both prearticular tooth plates was determined to taxonomically belong to the genus Macropycnodon, or possibly conspecific with M. streckeri (Hibbard) that is previously known only from a vomerine tooth plate. The complete set of dentition allowed us to support a previous study suggesting that the genus Macropycnodon is a junior synonym of Acrotemnus Agassiz, where the genus is now known from at least four species confined to the Turonian: 1) A. faba (UK); 2) A. streckeri (USA); 3) A. megafrendodon (USA); and 4) an unnamed species of Acrotemnus (Nigeria). The new specimen from Texas is here conservatively referred to as Acrotemnus cf. A. streckeri, and based on the size of the left cleithrum preserved in the specimen, the individual is estimated to be about 1.3 m in total length. Acrotemnus spp. collectively represent a group of large pycnodont fishes that inhabited the seas directly connected to the Tethys Ocean during the Turonian.

From Presidio to the Pecos River: Surveying the United States–Mexico Boundary along the Rio Grande, 1852 and 1853 by Orville B. Shelburne

Reviewed by: From Presidio to the Pecos River: Surveying the United States–Mexico Boundary along the Rio Grande, 1852 and 1853 by Orville B. Shelburne Andrew J. Milson From Presidio to the Pecos River: Surveying the United States–Mexico Boundary along the Rio Grande, 1852 and 1853. By Orville B. Shelburne. (Norman: University of Oklahoma Press, 2020. Pp. 312. Illustrations, notes, bibliography, index.) The agreement reached in the Treaty of Guadalupe Hidalgo of 1848, which ended the U.S. war with Mexico, required an accurate survey of the new international boundary between Mexico and the United States. One portion of that boundary along the Rio Grande between approximately 102°40′ and 104°40′ west longitude consisted of particularly remote and treacherous terrain that made survey work difficult. Much of this area today is known as the Big Bend National Park. From Presidio to the Pecos River by Orville B. Shelburne provides a detailed account of the survey parties, led by Marine Tyler Wickham Chandler in 1852 and Nathaniel Michler in 1853, which completed the mapping of this region. The exact course of the Rio Grande from present-day Presidio, Texas, to its confluence with the Pecos River was unknown in 1852, but it was understood that the river flowed through steep canyons. M. T. W. Chandler was ordered to lead an under-resourced surveying party for the first time in his career across an unknown distance, through a territory intersected by Cherokee trails and along a river reported to flow across large falls. The Chandler party successfully mapped 209 miles of the river from August to November 1852 and ultimately produced five boundary maps that were included in the final set of fifty-four official maps approved by the joint boundary commission. But the Chandler survey fell short of the Pecos River after two months of tribulations such as boat wrecks and arduous overland detours. No lives were lost, but the men suffered from limited rations, exhaustion, and tattered clothing. The Michler survey party commenced in the summer of 1853 to complete the final segment, but it was successful in mapping only ninety-four miles upstream of the Pecos River. The thirty-four-mile gap left between the two surveys consisted of the Lower Canyons of the Rio Grande, including San Francisco Canyon, where it was impossible for a party equipped with wagons and wooden boats to navigate the steep canyons and treacherous rapids. Rather than admit to the gap, Michler drew a generic meandering line to represent the canyons portion of the river. Shelburne's research on the boundary survey is brought to life by the [End Page 481] unpublished field notes and correspondence of botanist Charles C. Parry, who served with the Chandler party. Parry's descriptions and sketches provide a rich record of the route and experiences of the Chandler survey. The greatest strengths of From Presidio to the Pecos River are its outstanding maps and illustrations. Throughout the book, Shelburne offers juxtaposed images of historical sketches alongside high-quality, present-day photographs, as well as comparisons of sections of the survey maps with present-day maps and aerial imagery. Any cartophile will be thoroughly impressed by the outstanding cartographic design displayed throughout Shelburne's book. Carol Zuber-Mallison should be congratulated for her exceptional work in producing these gorgeous maps. Particularly stunning are the maps that occupy a two-page spread in the book, thereby providing a view that is both detailed and expansive. In sum, this book should be of great interest to both scholars and general readers who appreciate historical geography and the history of cartography. Andrew J. Milson University of Texas at Arlington Copyright © 2021 The Texas State Historical Association

The Essential J. Frank Dobie ed. by Steven L. Davis

Reviewed by: The Essential J. Frank Dobie ed. by Steven L. Davis William Jensen Steven L. Davis, ed., The Essential J. Frank Dobie. College Station: Texas A&M UP, 2019. 320 pp. Hardcover, $28. The folklorist J. Frank Dobie holds a strange spot in the American canon. Popular and influential while alive, he has become something of an invisible giant within the literary community since his death in 1964. Though many of his books are now out of print, his writings loom over contemporary letters. Without Dobie there is no Larry McMurtry, there is no Cormac McCarthy. Without Dobie there would be no James Wade, Philipp Meyer, or Rick Bass. Though criticized for his negative depictions of Mexican Americans while simultaneously glorifying the violence of cowboys and the Texas Rangers, Dobie remains the grandfather of Southwestern literature. Now Steven L. Davis has taken on the herculean task of making a portable J. Frank Dobie reader. I should mention that Davis is the curator of the Wittliff Collections at Texas State University where I teach; we’ve met. If anyone was going to make an anthology of Dobie, it should be Davis, who literally wrote the book about Dobie. His biography, J. Frank Dobie: A Liberated Mind, a gem of literary biography, came out in 2009. The anthology’s selections range from Dobie’s most popular works to previously unpublished pieces. A large variety of sections have never appeared in book form. This book is not simply a “Greatest Hits” but a coalescence of a man, his ideas, and his passions. Broken into nine sections, Davis has compiled Dobie’s folklore, journalism, and even some of his personal letters into an impressive compilation. Some chapters are obvious choices, such as “Stompedes” from The Longhorns and “The Buried Gold at Fort Ramirez” from Coronado’s Children: Tales of Lost Mines and Buried Treasures of the Southwest. Of course not every famous story is included. Other beloved chapters from Tales of Old-Time Texas and A Vaquero of the Brush Country are absent. Dobie’s body of work is too vast to include everything. What is fascinating is that Davis has not limited this anthology to just Texas and the Southwest; he includes a healthy serving of Dobie’s essays, correspondence, and reporting from Europe during the World Wars. Also included are speeches [End Page 85] and articles concerning politics and education, which might not excite some but are important for painting a portrait of a man who cared deeply about people, literature, and conservation. Dobie led an active life. He fought for the desegregation of the University of Texas, and he worked to save the Longhorn cattle breed from dying out. Big Bend National Park also owes Dobie a debt. This anthology shows all of the man’s passions and philosophies. Dobie may have been known as “Mr. Texas,” but he was obviously a humanitarian before he was a regionalist. Some aspects of this book may upset Dobie purists. Davis has taken it upon himself to make various edits, which range from deleting redundancies to rearranging entire paragraphs. Though highly erudite, Dobie’s voice was formed more around the campfire than the peer-reviewed journal. The role of the editor (any editor) is always a delicate act between strengthening the author’s voice and completely altering it, though occasionally a complete overhaul is necessary. Davis’s edits go unnoticed in the best way. Honestly, Dobie reads better now than ever. Though a national Dobie renaissance is unlikely, this anthology will help seal his stature not just as a man of letters but a man of ideas. Literature, like music, goes through various trends and styles, and while some artists are rediscovered, others are forgotten, rejected, or flat-out cancelled. The selections in this book create a strong argument to keep Dobie alive and well into the twenty-first century. This handsome anthology is highly recommended for college courses on western literature and American folklore, and it will most likely become the new standard of all of Dobie’s works. Steven L. Davis makes a solid argument for why J. Frank Dobie is indeed essential. [End Page 86] William Jensen Texas State University...

Morphology and neurovascular anatomy of a titanosaur (Dinosauria, Sauropoda) osteoderm from the Upper Cretaceous of Big Bend National Park, Texas

Osteoderms (ossified dermal elements) are among the most distinctive features of Titanosauria, a speciose clade of Cretaceous sauropods. Though osteoderms are often described as armor, hollow osteoderms have also been interpreted as mineral storage sites. A new specimen (TMM 45888-1) from the Upper Cretaceous Javelina Formation, Big Bend National Park, Texas, provides insights into osteoderm structure and function. It is oval with a cusp at one end and grooved marginal ornamentation, resembling certain specimens from Argentina but without a keel. It is not divided into bulb and root regions. TMM 45888-1 is the first titanosaur osteoderm from Texas. It cannot be referred to a species but is similar to the osteoderms of Alamosaurus, the only known titanosaur from North America.X-ray CT scans reveal that the interior of TMM 45888-1 is not hollow. Large neurovascular channels connect foramina on the deep, superficial, and marginal faces. The channels are concentrated along the deep face, at the ends, and passing through the center from deep to superficial. The osteoderm was potentially capable of providing mineral storage, localized defense, and display functions based on its vasculature, material properties, and shape. Whole-body defense, vertebral stabilization, and thermoregulation are rejected as functions based on apparent osteoderm scarcity, lack of articulations, and limited superficial vasculature. Osteoderms vary in gross and interior morphology among lithostrotians, necessitating caution when generalizing functions across the clade.

An angiosperm woodland in the Javelina Formation (Upper Cretaceous), Big Bend National Park, Texas, U.S.A.

Part of a paleo-forest comprised of eight in situ permineralized tree stumps is preserved in the Javelina Formation (middle Maastrichtian, c. 69 Ma) near Alamo Creek in western Big Bend National Park. The stumps are rooted in an immature organic-rich paleosol resembling a modernday Aquept, developed in a landscape depression subject to gleization with a shallow fluctuating groundwater table. Seven of the stumps pertain to the dicotyledonous angiosperm Metcalfeoxylon, and one is a cuppressoid/podocarpoid conifer, indicating that is part of a mixed conifer-dicot forest. The site exhibits a woodland architecture, with stands of closely spaced trees separated on average by 10 m, and open gaps over 100 m in between. Trunk diameters vary from 33 to 97 cm, with estimated crown heights from 23 to 48 m, and represent trees of varied ages in a mature forest. Irregular growth rings are developed in the conifer wood, but absent in the Metcalfeoxylon woods. The local climate may have had one or more annual dry seasons, and the conifers were either more susceptible to moisture stress, or genetically predisposed to express growth rings more markedly than the contemporaneous dicots. Metcalfeoxylon is also the dominant tree type at another paleo-forest preserved near McKinney Spring in the underlying Aguja Formation (late Campanian, c. 75 Ma). Metcalfeoxylon may have grown preferentially in low-lying riparian environments subject to flooding and burial by alluvial overbank deposits, thus favorable to preservation of the stumps in situ. A deficiency of precipitation, along perhaps with browsing pressure exerted by dinosaur herbivores, may have been responsible for maintaining the open woodland physiognomy evident at both sites.

Taxonomic Revision of the Genus Paranametis Burke, 1960 (Coleoptera: Curculionidae: Entiminae: Byrsopagini) in North America

The genus ParanametisBurke, 1960 is revised for North America (including northern Mexico). Paranametis distinctaBurke, 1960 is known from western Texas, New Mexico, and northern Mexico. Phyxelis latirostrisBlatchley, 1916 is resurrected from synonymy with Phyxelis rigidus (Say, 1832) and treated as a valid species transferred to the genus Paranametis as Paranametis latirostris (Blatchley, 1916), resurrected status, new combination. Two new species are described herein: Paranametis burkei Anderson, new species (type locality Big Bend National Park, Brewster County, Texas); and Paranametis howdenae Anderson, new species (type locality Mexico, Nuevo Leon, 5.3 mi. S La Escondida). All species are described or redescribed, natural history information is summarized, and a listing of locality data from all specimens examined is included and mapped. A key is provided to the species of the genus. All species are represented by habitus images and images of taxonomically significant structures. Paranametis species share a similar ramose/papillate/microfilamentous scale form with species of the genera Phyxelis Schoenherr, 1843 and LeptopinaraO'Brien, 1981, which is unique among North American Byrsopagini.

Controls On Sedimentation and Cyclicity of the Boquillas and Equivalent Eagle Ford Formation from Detailed Outcrop Studies of Western and Central Texas, U.S.A.

AbstractFacies of the Boquillas and equivalent Eagle Ford Formation can be assigned to two associations: a hydrodynamically recycled association and a pelagic association. The hydrodynamically recycled association is composed of lenticular to continuous cross-laminated lime packstone–grainstone, heterolithic facies, and intraclastic grainstone conglomerate with intercalated calcareous mudrock. Sharp bedding contacts, abundant scours, ripple cross-lamination, oscillatory-current indicators, hummocky cross-bedding, and rounded clasts indicate recycling of the bottom sediments by storms and bottom currents above storm wave base (SWB). The pelagic association is composed of continuous lime packstone to grainstone and chalk beds with intercalated calcareous mudrock. Gradational contacts and planar lamination indicate dominant deposition by pelagic rain, but scour surfaces, coarse-fine alternations, and ripple cross-laminae indicate the influence of bottom currents below SWB.Vertical shifts between the hydrodynamically recycled association, interpreted to represent storm agitation of the seafloor during falls in sea level, alternate with the pelagic association and define four sequence boundaries and three depositional sequences with a lower-order periodicity (third-order periodicity, ca. average 2.4 My). Sequence boundaries correspond approximately to member boundaries recognized by gamma-ray profiles. Spectral analysis reveals higher-frequency mudrock–carbonate cycles prominent in the pelagic association, likely resulting from Milankovitch climate forcing of planktonic carbonate productivity versus clay flux. Comparison of gamma-corrected spectra with absolute age constraints reveals that the Ernst Tinaja section (in Big Bend National Park) is less than 28% complete. This is interpreted to result from abundant depositional hiatuses and erosional gaps that occur at the bed scale and at member boundaries within and bounding the Eagle Ford Formation.We demonstrate that deep-marine pelagic deposits in epicratonic settings may be subject to a complex interaction of depositional processes including pelagic rain and recycling by bottom currents and wave-generated currents modulated by low-frequency sea-level fluctuation and high-frequency fluctuations in sediment supply.

An unusual ‘shovel-billed’ dinosaur with trophic specializations from the early Campanian of Trans-Pecos Texas, and the ancestral hadrosaurian crest

We describe a new genus and species of hadrosaurid dinosaur, Aquilarhinus palimentus, from the lower shale member of the Aguja Formation (lower Campanian) of Big Bend National Park, south-western Texas. This species is characterized by several autapomorphies of the facial skeleton and mandible, including a crest composed of broadly arched nasals. Notably, the symphyseal processes of the dentary are elongated and reflected dorsally, causing the dentaries to meet with a ‘W’-shaped anterior profile. A hypothesized shovel-shaped ‘bill’, associated with widening of the skull, in A. palimentus might have been used in shovelling out and scooping up semiaquatic vegetation. This animal is otherwise superficially similar to kritosaurins like Gryposaurus but differs in the retention of key plesiomorphic character states in the maxilla and jugal. Phylogenetic analysis reveals Aquilarhinus to be a non-saurolophid hadrosaurid allied to Latirhinus from the late Campanian of Mexico, which bears a similar broadly arched nasal. The recognition of this lineage adds to the diversity of non-saurolophid hadrosaurids and points to the existence of a hitherto unknown diversity of ‘duck-billed’ dinosaurs outside of the saurolophine-lambeosaurine radiation. Cranial crests were ancestral for early hadrosaurids and evolved before the saurolophid radiation. Ancestrally, crests were ‘solid’, and consisted of arched nasals. These were retained among kritosaurins and subsequently modified into the diverse crest morphologies observed among derived saurolophines. Lambeosaurine ‘hollow-crested’ crest morphology departed from the ancestral, ‘solid-crested’ pre-saurolophid condition early following the origin of that clade.http://www.zoobank.org/urn:lsid:zoobank.org:pub:F7CE1BE7-1A76-4628-8510-93C37A1A807E

Statistical methods to enable practical on-site tomographic imaging of whole-core samples

Statistical methods enable the use of portable industrial scanners with sparse measurements, suitable for fast on-site whole-core X-ray computed tomography (CT), as opposed to conventional (medical) devices that use dense measurements. This approach accelerates an informed first-stage general assessment of core samples. To that end, this novel industrial tomographic measurement principle is feasible for rock-sample imaging, in conjunction with suitable forms of priors in Bayesian inversion algorithms. Gaussian, Cauchy, and total variation priors yield different inversion characteristics for similar material combinations. An evaluation of the inversion performance in rock samples considers, in a discrete form, conditional mean estimators, via Markov Chain Monte Carlo algorithms with noise-contaminated measurements. Additionally, further assessment indicates that this statistical approach better characterizes the attenuation contrast of rock materials, compared with simultaneous iterative reconstruction techniques. Benchmarking includes X-ray CT from numerical simulations of synthetic and measurement-based whole-core samples. To this end, we consider tomographic measurements of fine- to medium-grained sandstone core samples, with igneous-rich pebbles from the Miocene, off the Shimokita Peninsula in Japan, and fractured welded tuff from Big Bend National Park, Texas. Bayesian inversion results confirm that with only 16 radiograms, natural fractures with aperture of less than 2 mm wide are detectable. Additionally, reconstructed images found approximately spherical concretions of 6 mm diameter. To achieve similar results, filtered back projection techniques require hundreds of radiograms, only possible with conventional laboratory scanners.

Establishment of Arundo Wasp, Tetramesa romana1, at Big Bend National Park

Establishment of Arundo Wasp, Tetramesa romana1, at Big Bend National Park

Salinity tolerance of a rare and endangered unionid mussel, Popenaias popeii (Texas Hornshell) and its implications for conservation and water management

Unionid mussels are considered sensitive to salinity and there is growing concern in arid and semi-arid regions that declining flows coupled with anthropogenic impacts are amplifying natural salinity levels. In this study, we tested the effects of varying salinity concentrations (3.0, 4.0, 5.0, 6.0, 7.0 and 10.0 ppt NaCl) on survival of adult Popenaias popeii, (Texas Hornshell). This species occurs in the Rio Grande basin of Texas and northern Mexico, an arid to semi-arid stream plagued by salinization, and was recently listed as Endangered under the U.S. Endangered Species Act. We performed 2, 4, and 10-day toxicity tests on individuals from two disjunct populations: Laredo, TX, and the Lower Canyons of the Rio Grande near Big Bend National Park. We found no significant differences in LC50 estimates between populations at 96-hrs or 10-days but significant differences in TUD50s at 5 ppt between populations, which indicates that tolerance does not vary but sensitivity may between these populations. Overlaying LC50 estimates at 10-days for both populations on plots of salinity (ppt) measured over time, we show parts of the Rio Grande periodically approach or exceed 4.0 ppt, indicating these reaches are becoming unsuitable for P. popeii and populations within them at risk.

Warm Terrestrial Subtropics During the Paleocene and Eocene: Carbonate Clumped Isotope (Δ47) Evidence From the Tornillo Basin, Texas (USA)

AbstractRecords of subtropical climate on land from the early Paleogene offer insights into how the Earth system responds to greenhouse climate conditions. Fluvial and floodplain deposits of the Tornillo Basin (Big Bend National Park, Texas, USA) preserve a record of environmental and climatic change of the Paleocene and the early Eocene. We report carbon, oxygen, and clumped isotopic compositions (δ13C, δ18O, and Δ47) of paleosol carbonate nodules from this basin. Mineralogical, geochemical, and thermal modeling evidence suggests that the measured isotopic values preserve primary environmental signals with a summer bias with the exception of data from two nodules reset by local igneous intrusions. The unaltered nodules record Δ47 temperatures of 25 ± 4 and 32 ± 2 °C for the Paleocene and early Eocene nodules, respectively, showing an increase in average summer temperatures of 7 ± 3 °C. Calculations of δ18O of soil water are −2.8 ± 0.7‰ and −0.8 ± 0.4‰ (standard mean ocean water) for the early‐mid‐Paleocene and late Paleocene‐early Eocene, showing an increase of 2.0 ± 0.9‰. The increase in temperature and δ18O values likely relates to a rise in atmospheric pCO2, although we cannot rule out that changes in paleosol texture and regional precipitation patterns also influence the record. Comparison with Δ47 estimates of summer temperature from the Green River and Bighorn Basins (WY) highlights that terrestrial surface temperatures are heterogeneous, and latitudinal temperature gradients on land remain undetermined. Previously published paleoclimate models predict summer temperatures that are 2 to 6 °C higher than our estimate; discrepancies between climate models and proxy data persist at lower latitudes.

A revision of the genus Eurhoptus LeConte, 1876 (Curculionidae, Cryptorhynchinae) of America north of Mexico

The genus Eurhoptus LeConte, 1876 is revised for America north of Mexico. Eight species are recognized including E.pyriformis LeConte, 1876, E.sordidus (LeConte, 1876), E.curtus (Hamilton, 1893), resurrected name, and five new species as follows: E.rileyi new species (type locality, Texas, Hidalgo County, Bentsen Rio Grande State Park), E.imbricatus new species (type locality, Texas, Bandera County, Lost Maples State Natural Area), E.cariniventris new species (type locality, Texas, Bandera County, Lost Maples State Natural Area), E.occidentalis new species (type locality, Texas, Brewster County, Big Bend National Park), and E.aenigmaticus new species (type locality, Alabama, Winston County, Bankhead National Forest). Descriptions or redescriptions, and images of taxonomically important structures are presented for all species. A key to the eight species is included.

Parasitic interactions among Trypanosoma cruzi, triatomine vectors, domestic animals, and wildlife in Big Bend National Park along the Texas-Mexico border

National parks attract millions of visitors each year. Park visitors, employees, and pets are at risk of infection with various zoonotic pathogens, including Trypanosoma cruzi, causative agent of Chagas disease. Big Bend National Park is located along the Texas-Mexico border in a region with endemic triatomine insects- vectors of T. cruzi- yet the degree to which the parasite is transmitted in this region is unknown. We collected triatomines for T. cruzi detection and discrete typing unit (DTU) determination, and conducted blood meal analyses to determine recent hosts. As an index of domestic/peridomestic transmission, we tested residential dogs in the Park for exposure to T. cruzi. From 2015 to 2017, 461 triatomines of three species—Triatoma rubida, Triatoma gerstaeckeri, and Triatoma protracta—were collected in and around the Park. Adult triatomine encounters peaked in June of each year (52.8% of collections). We detected an overall infection prevalence of 23.1% in adult triatomines (n = 320) and 4.2% in nymph triatomines (n = 24). DTU TcI was the only T. cruzi strain detected. Of 89 triatomines subjected to blood meal analyses, vertebrate host DNA was successfully amplified from 42 (47.2%); blood meal sources included humans, domestic animals, and avian and mammalian wildlife species. Tested dogs were considered positive if reactive on at least two independent serologic assays; we found 28.6% seroprevalence in 14 dogs. These findings reveal interactions between infected triatomines, humans, dogs, and wildlife in and around Big Bend National Park, with potential risk of human disease.

Functional distance and establishment of non-native species with complex life cycles

More than 80% of animals have complex life cycles and undergo distinct changes in ecology and morphology during development. The strength and type of factors regulating each life-stage may differ as an organism may occupy different niches during ontogeny. We examined the functional distance at larval and adult life-stages of two non-native anurans (Green Tree Frog [Hyla cinerea] and Bullfrog [Lithobates catesbeianus]) that have established in a Chihuahuan Desert anuran assemblage in Big Bend National Park. Both life stages of both non-native species occupied niche space outside of the native assemblage. At the larval stage, the ability of the tadpoles to utilize permanent aquatic habitats and coexist with predatory fishes differentiated the non-native species from the majority of the native species that are restricted to temporary pools. At the post-metamorphic life stage, each species appears to have established by exploiting unoccupied habitat and trophic niches in the recipient community. The arboreal habits of H. cinerea may enable it to utilize resources in microhabitats that are otherwise not used by native species because arboreal frogs are absent from this native assemblage. The large body size of post-metamorphic L. catesbeianus may enable it to utilize larger food resources that are otherwise unavailable to the smaller-bodied natives. Separate comparison of larval and adult functional traits between non-natives and the native community may help predict their potential establishment or invasion success as well as aid in the development of stage-specific control or eradication efforts.

Revised age constraints for Late Cretaceous to early Paleocene terrestrial strata from the Dawson Creek section, Big Bend National Park, west Texas

Revised age constraints for Late Cretaceous to early Paleocene terrestrial strata from the Dawson Creek section, Big Bend National Park, west Texas