Primer registro fósil del gasterópodo Cincinnatia (Hydrobiidae: Nymphophilinae) en México

Se describe el primer registro en México de conchas fósiles del gasterópodo de aguas continentales del género Cincinnatia Pilsbry, 1891, encontrados en sedimentos fluviátiles del Pleistoceno tardío en el valle de Acatita, Coahuila. La morfología y el análisis discriminante de las conchas indican que el material fósil corresponde a Cincinnatia integra (Say, 1821), una especie reciente con una distribución disjunta entre la parte oriental de los EUA y sur de Canadá y un área pequena˜ en la cuenca del río Pánuco, San Luís Potosí, México. Los nuevos hallazgos marcan el límite más occidental de la distribución original del género Cincinnatia y sugieren una conexión entre ambas áreas norte-sur en la extensión original de C. integra, hoy separadas, según registros, por más de 700 km, desde el Pleistoceno tardío hasta tiempos subrecientes. Considerando que el norte de México es hasta la fecha una región poco muestreada con referencia a los miembros de la familia Hydrobiidae, existe una alta probabilidad de hallazgos de poblaciones vivas de Cincinnatia en las cuencas altas de esta región así como en sitios acuáticos de la parte norte de los estados de Coahuila, Nuevo León y Tamaulipas. ABSTRAC The first record of fossil shells of the freshwater gastropod genus Cincinnatia Pilsbry, 1891 found in fluvial sediments of the late Pleistocene in the Acatita Valley, Coahuila, Mexico, is described. Morphology and discriminant analysisindicate that the fossil material correspond to Cincinnatia integra (Say, 1821), an extant species with a disjunct distribution between the eastern part of United States of America and southern Canada and a small area near Pánuco River, San Luis Potosí, Mexico. The new findings mark the westernmost limit of the original distribution of Cincinnatia and suggest a north-south connection between both areas in the original extension of C. integra, today separated according to the records by more than 700 km, since the late Pleistocene to sub-recent times. Considering that northern Mexico to date is under-sampled for the Hydrobiidae, there is a high probability of finding live populations of Cincinnatia in this region and in other aquatic habitats in the northern part of the states of Coahuila, Nuevo León, and Tamaulipas

Rare, Imperiled, and Recently Extinct or Extirpated Mollusks of Utah: A Literature Review

About 139 species of mollusks are known to occur, or within historical times to have occurred, in Utah. The number of known Utah mollusks is not fixed and can be expected to continue to change, increasing as new molluscan discoveries are made in Utah and possibly decreasing as taxonomic revisions change our concept of how many valid mollusk species exist. This report represents one of the end products of a review of literature—published journal articles and books as well as unpublished agency reports—dealing with mollusks in Utah. The goals of this review were to determine (1) which species have been documented from the state, (2) extent of knowledge of the status—abundance, distribution, conservational needs, and so forth—of each of the species in Utah, and, thus, (3) which species are of conservational concern in the state. This report summarizes the assembled information pertaining to the last goal, the 79 molluscan species that are of conservational priority—or of conservational interest in the cases of those believed to be extirpated or extinct; it is intended to help guide current management of the molluscan resources of the state as well as to identify gaps in existing knowledge that will need to be filled in order to manage these resources more effectively in the future. Some of the understanding that is important for truly effective management of Utah\u27s mollusks is lacking, especially with regard to our knowledge of threats to and population trends in these species. Threats to various species discussed in this report should be understood, in most cases, as potential threats, often based on educated guesses. Similarly, information pertaining to population trends of mollusks in Utah is largely unavailable from the existing literature. Despite the incompleteness of reported information concerning Utah mollusks, much is known, and this information obtained from the literature provides an valuable base from which to plan future work. Mollusks, as a group, are thought to be among the most endangered of animal groups that occur in North America, but this is a new awareness, and conservational management attention has only recently begun to be directed toward this group. The Utah Division of Wildlife Resources now has management authority for all mollusks in the state and is establishing mechanisms and procedures for the management and protection of the state\u27s molluscan resources

Research poster: Climate change impacts to groundwater, springs hydrology and aquatic communities Amargosa Desert and Death Valley National Park, Nevada and California

Research poste

TAXONOMIC STATUS AND PHYLOGENY OF THE SAN BERNARDINO SPRING SNAIL POPULATIONS INTO THE GENUS PYRGULOPSIS IN SONORA AND ARIZONA

The San Bernardino springsnail (Pyrgulopsis bernardina) inhabits springs in the upper San Bernardino River (SBR) basin in southeastern Arizona and northeastern Sonora. Loss of populations in Arizona associated with habitat degradation has resulted in concern for the continued persistence and viability of the species. Springsnails at the Arroyo San Bernardino (ASB) sub-basin in Sonora are considered P. bernardina but this has not been validated through genetic studies to receive legal protection. The species of Pyrgulopsis detected in the Arroyo Cajon Bonito (ACB) sub-basin in Sonora sites is not known. The goal of this study is to provide genetic information to resource managers to clarify the taxonomic relationships between populations of Pyrgulopsis in the upper SBR basin in Sonora with those historically found at the type locality in Arizona based on cytochrome oxidase 1 (COI) gene fragment. COI fragments from the two sub-basins samples in Sonora, confirms that Pyrgulopsis are conspecific with type locality samples from Arizona. Maximum parsimony and maximum likelihood analysis of all populations, agree with the current systematics of the species. Monophyly of all populations of P. bernardina was observed, and populations within each sub-basin form two monophyletic clades. Conservation planning should recognize the two sub-basins genetic divergence. Within the ASB clade, genetic relationships suggest historical connectivity with the type locality in Arizona

Ecohydrogeology of Owens Valley, California Spring Systems: Relationships between Geochemistry, Benthic Macroinvertebrates, and Microbial Communities

Integrating hydrogeology and aquatic ecology has intrigued ecologists and hydrologists. The challenges and importance of integrating these disciplines in groundwater-dependent ecosystems (e.g., springs) have been recognized and studied in mesic regions where these systems are at the headwater of streams. Although ecologists and hydrogeologists have studied aridland springs in terms of taxonomic data, habitat classifications, landscape placement, and sampling techniques, the current state of the science (i.e., integration of hydrogeological parameters and spring ecology) is still in its early stages.This dissertation provides insight into the association between hydrochemistry, invertebrate ecology, and microbial ecology in aridland springs in the southwestern Great Basin. Water chemistry, benthic macroinvertebrates (BMI), and benthic microbial samples were collected from undisturbed rheocrene (flowing into a channel) springs emerging along the Sierra Nevada Frontal Fault Zone in Owens Valley, California. We also sampled one regional spring on the eastern side of Owens Valley. Samples were collected during the summers of 2016 and 2017. First, we examined the temporal variability of benthic macroinvertebrate (BMI) communities before and after 17-years of hydrologic disturbances (frequent droughts and scouring floods) in 2000 and 2017 (Chapter 2). The results showed that persistent desert springs act as refugial aquatic habitats and protect the benthic communities, especially crenobiontics (obligatory spring dependent), during frequent drought and flood in arid regions. These findings motivated us to study the potential factors in shaping these stable communities. To do so, we compared the spatial distribution of BMI communities with the environmental characteristics of spring waters (Chapter 3). The results revealed that the geochemical fingerprint of spring water has a prominent role in shaping the structure of BMI communities in undisturbed aridland springs. Finally, we compared the ecological patterns of BMI and microbial communities found in these springs. Multivariate statistical and co-occurrence analyses were applied to both BMI and microbial communities to understand the relationship between these biological organizations (Chapter 4). The results indicated a relatively similar ordination pattern among BMI and microbial communities. We also highlighted the hydrochemistry as the primary driver of characterizing both microbial and BMI communities

The Amnicolidae of Michigan: distribution, ecology, and taxonomy

http://deepblue.lib.umich.edu/bitstream/2027.42/56302/1/MP057.pd

Distributions and Habitat Associations of Blue Point Pyrgulopsis and Blue Point Tryonia

Springsnails and other crenophilic species are often of conservation concern due to endemism, narrow habitat requirements, and susceptibility to habitat degradation. Because there is a distinct lack of natural history information for many of these organisms, management of species that are of concern is often based on data from non-target species related to the species of interest. In this thesis, I provide background information regarding springsnails in western North America (Chapter 1), describe a study investigating the distribution and habitat associations of two springsnails endemic to a single spring (Chapter 2), and provide supplemental information on habitat characteristics associated with these springsnails (Chapter 3). Blue Point Spring is located in southern Nevada within Lake Mead Natural Recreation Area. This spring is occupied by several endemic species, including two springsnails: Pyrgulopsis coloradensis and Tryonia infernalis. These springsnails were known to occupy the upper segment of the spring, with high abundances in the source pool, but further information on their natural history was limited. The goal of my research was to assess the distribution, abundance, and habitat associations of P. coloradensis and T. infernalis at Blue Point Spring, in order to better inform resource management planning at the site. I monitored the distributional abundances of these species across the upper 20 meters of Blue Point Spring, sampling every 8 weeks over one year. I collected springsnails using direct substrate sampling, artificial substrate sampling, and vegetation sampling. Both springsnail species were present in high abundances in the source pool (upper 10 meters of the spring) where fish do not occur. Seasonally high abundances on artificial substrate samplers reached 78844/m2 for P. coloradensis and 26311/m2 for T. infernalis. I identified some level of habitat partitioning between these two springsnail species, as generalized linear mixed modeling indicated that species identity was a significant factor in springsnail distribution and abundance. Pyrgulopsis coloradensis reached its highest densities at meters 2.5–3.5 downstream, and T. infernalis reached its highest densities at meter 5.5 downstream. Modeling further indicated that T. infernalis may be selecting shadier habitats than P. coloradensis. Other factors identified as significant included pH, conductivity, meters downstream, percent vegetation cover, and location on the north or south edge of the spring. I supplemented the modeling with observational studies to assess springsnail movement and predation by nonnative fishes. The observational studies indicated that springsnails move at high rates of speed, averaging ~ 0.7 cm/min for P. coloradensis and ~ 0.9 cm/min for T. infernalis, and could colonize tile samplers in about 2.12–27.06 hours. The rate of movements likely impacted the experiments with fish exclusions. Feeding trials and a fish exclusion experiment indicated that nonnative fishes pose a significant threat to springsnails at Blue Point Spring, with convict cichlids, in particular, appearing to be a major limiting factor in the distribution of both P. coloradensis and T. infernalis. The differences in distributional abundance between springsnail species, as well as the impact of nonnative fishes are critical information to consider when making management decisions at Blue Point Spring, including potential habitat modification to improve conditions for other species of interest at the site or eradication of nonnative fishes from portions of the spring

Terminal-occupation community patterns at Lyon\u27s Bluff (22OK520) in Oktibbeha County, Mississippi:sedimentological, molluscan, artifactual, and geophysical evidence

Prehistoric cultures are often studied by intrasite artifact variation and quantity without much consideration of how prehistoric populations interacted locally and regionally. Archaeologists can identify and study patterns associated with activities within a specified radius in order to gain an understanding of cultural operations. Identifying a social framework for a prehistoric society allows the investigation of group organization such as status differentiation, shared rituals, and the construction and maintenance of earthworks and living areas. That facilities were constructed for specialized use within a community is evidenced by the presence of earthworks and mounds at many sites (Lewis et al. 1998:16-17). Less well understood is how community patterns reflect social organization. The purpose of this thesis is to better document the number and distribution of structures at Lyon’s Bluff, a Mississippian to Protohistoric-period mound site in Oktibbeha County, Mississippi. The focus will be on the last part of the occupation at the site, i.e., on materials recovered from the plowzone. A method employing molluscan remains and sedimentological evidence is used that allows for the delineation of structure locales using plowzone samples. Additional evidence is provided by artifact distributions and geophysical (magnetic gradiometer) data

DNA barcoding of springsnails (Mollusca, Gastropoda, Caenogastropoda) endemic to the Trans-Pecos region of Texas (USA)

In desert environments, unique communities depend on groundwater from springs, including a diverse radiation of small (<5 mm) snails found in the desert across the southwestern United States. Nearly all springsnail species are considered critically imperiled with their existence depending on maintenance of spring-flows in regions of declining water availability. Extant, endemic springsnails in the Trans-Pecos region of Texas include one species of Pseudotryonia Hershler, 2001, five nominal Tryonia W. Stimpson, 1865 (Cochliopidae) and seven Pyrgulopsis Call & Pilsbry, 1886 (Hydrobiidae). Four of these are classified as endangered under the US Endangered Species Act. Surveys for springsnails were conducted at 128 sites, including 13 sites that were previously reported localities, and 115 previously unsampled spring sites were also searched for new springsnail populations. Sequences of the DNA barcoding region were used to establish a database of known sequences from the named species and confirm identifications of new populations encountered. We report eight new springsnail populations, including new records for T. metcalfi Hershler, Liu & Landye, 2011, T. cheatumi (Pilsbry, 1935), P. ignota Hershler, Liu & Lang, 2010, P. metcalfi (D.W. Taylor, 1987), and P. texana (Pilsbry, 1935). We were not able to recollect Juturnia brunei (D.W. Taylor, 1987), T. oasiensis Hershler, Liu & Landye, 2011, or P. davisi (D.W. Taylor, 1987). The DNA barcoding gap for Tryonia ranged from 1.56–4.47% and for Pyrgulopsis from 0.68–1.68%.&nbsp