A Guide to Sexing Salamanders of The Central Appalachians, USA

Documenting the sex of individuals encountered during wildlife research and monitoring activities is important for understanding and tracking changes in populations. However, sexing salamanders can be particularly difficult because secondary sex characters are often subtle or only visible during the breeding season, and guidance on species-specific sex determination is lacking from most field guides. The purpose of this guide is to provide a reference to assist biologists in the Central Appalachian region with identifying sex of live adult salamanders. In the main text we provide summary tables and figures to serve as concise references in the field. In Text S1 (Supplemental Material) we provide individual species accounts that contain concise yet comprehensive information for each species based on the published literature, as well as many images depicting sexually dimorphic characters. Our focal region encompasses partial or entire distributions for 56 species of salamanders in five families (Ambystomidae, Cryptobranchidae, Plethodontidae, Proteidae, and Salamandridae). We identified seven morphological characters that are strongly sexually dimorphic and useful for sexing live, non-anesthetized, adult salamanders in the field, with males of individual species exhibiting one to five of the characters. We identified >20 additional characters that are weakly sexually dimorphic, difficult to distinguish in the field, or species-specific. Our guide serves as a synthesis of sexually dimorphic characters available for salamanders in Central Appalachia, and we anticipate it will have broad value for researchers, monitoring programs, and salamander enthusiasts in eastern and central North America.

Quantifying shortening across the central Appalachian fold-thrust belt, Virginia and West Virginia, USA: Reconciling grain-, outcrop-, and map-scale shortening

We present a kinematic model for the evolution of the central Appalachian fold-thrust belt (eastern United States) along a transect through the western flank of the Pennsylvania salient. New map and strain data are used to construct a balanced geologic cross section spanning 274 km from the western Great Valley of Virginia northwest across the Burning Spring anticline to the undeformed foreland of the Appalachian Plateau of West Virginia. Forty (40) oriented samples and measurements of >300 joint orientations were collected from the Appalachian Plateau and Valley and Ridge province for grain-scale bulk finite strain analysis and paleo-stress reconstruction, respectively. The central Appalachian fold-thrust belt is characterized by a passive-roof duplex, and as such, the total shortening accommodated by the sequence above the roof thrust must equal the shortening accommodated within duplexes. Earlier attempts at balancing geologic cross sections through the central Appalachians have relied upon unquantified layer-parallel shortening (LPS) to reconcile the discrepancy in restored line lengths of the imbricated carbonate sequence and mainly folded cover strata. Independent measurement of grain-scale bulk finite strain on 40 oriented samples obtained along the transect yield a transect-wide average of 10% LPS with province-wide mean values of 12% and 9% LPS for the Appalachian Plateau and Valley and Ridge, respectively. These values are used to evaluate a balanced cross section, which shows a total shortening of 56 km (18%). Measured magnitudes of LPS are highly variable, as high as 17% in the Valley and Ridge and 23% on the Appalachian Plateau. In the Valley and Ridge province, the structures that accommodate shortening vary through the stratigraphic package. In the lower Paleozoic carbonate sequences, shortening is accommodated by fault repetition (duplexing) of stratigraphic layers. In the interval between the duplex (which repeats Cambrian through Upper Ordovician strata) and Middle Devonian and younger (Permian) strata that shortened through folding and LPS, there is a zone that is both folded and faulted. Across the Appalachian Plateau, slip is transferred from the Valley and Ridge passive-roof duplex to the Appalachian Plateau along the Wills Mountain thrust. This shortening is accommodated through faulting of Upper Ordovician to Lower Devonian strata and LPS and folding within the overlying Middle Devonian through Permian rocks. The significant difference between LPS strain (10%–12%) and cross section shortening estimates (18% shortening) highlights that shortening from major subsurface faults within the central Appalachians of West Virginia is not easily linked to shortening in surface folds. Depending on length scale over which the variability in LPS can be applied, LPS can accommodate 50% to 90% of the observed shortening; other mechanisms, such as outcrop-scale shortening, are required to balance the proposed model.

Common Spring Types in the Valley and Ridge Province: There Is More than Karst

ABSTRACT The Valley and Ridge Province (V&R) of the central Appalachians is rich in springs that support ecosystems, provide local water resources, and export water from the region. Although there has been extensive research on springs in the province, the focus has been on chemically variable karst springs. The purpose of this work is to identify common spring types found in the V&R based on an analysis of three regions. Three types of V&R springs are included in this comparison, and their relationship to more general classification systems is included. Headwater springs, located near ridge tops and along ridge flanks, are typically small, may be ephemeral, have localized flow paths, and are associated with siliciclastic units. Karst springs, generally located in the valleys, include both the more chemically variable limestone springs and the more stable dolomite springs. Thermal warm springs, with temperatures higher than the mean annual air temperature, are less common than the other spring types; they may be large and are typically associated with major thrust faults. The temperature, chemistry, and locations of the springs are controlled by the structural geology and topography as well as the formations and lithologies through which the recharge water travels. There is overlap in the water chemistry and storm responses of the spring groups, but some general trends can be identified, such as lower pH in the headwater springs. The V&R springs are critical resources, but their sustainability, chemistry, and hydrology need to be considered within the local geologic framework.

The MAGIC Experiment: A Combined Seismic and Magnetotelluric Deployment to Investigate the Structure, Dynamics, and Evolution of the Central Appalachians

The eastern margin of North America has undergone multiple episodes of orogenesis and rifting, yielding the surface geology and topography visible today. It is poorly known how the crust and mantle lithosphere have responded to these tectonic forces, and how geologic units preserved at the surface related to deeper structures. The eastern North American margin has undergone significant postrift evolution since the breakup of Pangea, as evidenced by the presence of young (Eocene) volcanic rocks in western Virginia and eastern West Virginia and by the apparently recent rejuvenation of Appalachian topography. The drivers of this postrift evolution, and the precise mechanisms through which relatively recent processes have modified the structure of the margin, remain poorly understood. The Mid-Atlantic Geophysical Integrative Collaboration (MAGIC) experiment, part of the EarthScope USArray Flexible Array, consisted of collocated, dense, linear arrays of broadband seismic and magnetotelluric (MT) stations (25–28 instruments of each type) across the central Appalachian Mountains, through the U.S. states of Virginia, West Virginia, and Ohio. The goals of the MAGIC deployment were to characterize the seismic and electrical conductivity structure of the crust and upper mantle beneath the central Appalachians using natural-source seismic and MT imaging methods. The MAGIC stations operated between 2013 and 2016, and the data are publicly available via the Incorporated Research Institutions for Seismology Data Management Center.