A thirty-year assessment of the endangered aquatic macrophyte, Zizania texana, endemic to the upper reach of the San Marcos River in Central Texas, USA

2021 ◽  
pp. 103482
Author(s):  
Jackie Poole ◽  
Jeffrey T. Hutchinson ◽  
Christopher R. Hathcock ◽  
David Han
Keyword(s):  
Aquatic Macrophyte ◽  
San Marcos ◽  
Central Texas

scholarly journals Comparative development and ocular histology between epigean and subterranean salamanders (Eurycea) from central Texas

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11840
Author(s):  
Ruben U. Tovar ◽  
Valentin Cantu ◽  
Brian Fremaux ◽  
Pedro Gonzalez Jr ◽  
Amanda Spikes ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Eye Morphology ◽  
Extreme Phenotypes ◽  
San Marcos ◽  
Central Texas ◽  
Surface Dwelling ◽  
Salamander Species ◽  
Barton Springs ◽  
Early Developmental ◽  
Subterranean Environment

The salamander clade Eurycea from the karst regions of central Texas provides an ideal platform for comparing divergent nervous and sensory systems since some species exhibit extreme phenotypes thought to be associated with inhabiting a subterranean environment, including highly reduced eyes, while others retain an ancestral ocular phenotype appropriate for life above ground. We describe ocular morphology, comparing three salamander species representing two phenotypes—the surface-dwelling Barton Springs salamander (E. sosorum) and San Marcos salamander (E. nana) and the obligate subterranean Texas blind salamander (E. rathbuni) - in terms of structure and size of their eyes. Eyes were examined using confocal microscopy and measurements were made using ImageJ. Statistical analysis of data was carried out using R. We also provide a developmental series and track eye development and immunolocalization of Pax6 in E. sosorum and E. rathbuni. Adult histology of the surface-dwelling San Marcos salamander (E. nana) shows similarities to E. sosorum. The eyes of adults of the epigean species E. nana and E. sosorum appear fully developed with all the histological features of a fully functional eye. In contrast, the eyes of E. rathbuni adults have fewer layers, lack lenses and other features associated with vision as has been reported previously. However, in early developmental stages eye morphology did not differ significantly between E. rathbuni and E. sosorum. Parallel development is observed between the two phenotypes in terms of morphology; however, Pax6 labeling seems to decrease in the latter stages of development in E.rathbuni. We test for immunolabeling of the visual pigment proteins opsin and rhodopsin and observe immunolocalization around photoreceptor disks in E. nana and E. sosorum, but not in the subterranean E. rathbuni. Our results from examining developing salamanders suggest a combination of underdevelopment and degeneration contribute to the reduced eyes of adult E. rathbuni.

scholarly journals Divergent patterns of ocular development and gene expression in the evolution of a subterranean salamander

2018 ◽  
Author(s):  
Ruben U. Tovar ◽  
Valentin Cantu ◽  
Brian P. Fremaux ◽  
Pedro Gonzalez ◽  
Dana M. García
Keyword(s):  
Developmental Stages ◽  
Ocular Tissue ◽  
Ocular Development ◽  
Evolution And Development ◽  
Extreme Phenotypes ◽  
San Marcos ◽  
Central Texas ◽  
Lens Vesicle ◽  
Surface Dwelling ◽  
Salamander Species

Relatively few studies have focused on the evolution and development of divergent nervous systems. The salamander clade (Eurycea) from the karst regions of central Texas provide an ideal platform for comparing divergent nervous and sensory systems, since some species exhibit extreme phenotypes thought to be associated with inhabiting a subterranean environment, including highly reduced eyes. We describe ocular development and examine early ocular protein expression (Pax6 and Shh), comparing between two salamander species representing two phenotypes: the surface dwelling Barton Springs salamander (E. sosorum) and the obligate subterranean Texas blind salamander (E. rathbuni). Between the two species, similarities during the development of ocular tissue (e.g. optic cup and lens vesicle) were observed during embryogenesis. However, during late stage embryogenesis the two species display markedly different patterns of Pax6 localization, which parallel patterns previously reported in a cavefish. A lens vesicle was observed in E. rathbuniembryos at stage 40, yet the lens is absent in adults, suggesting the regression of the lens during ontogeny. We also include adult histology of the surface dwelling San Marcos salamander (E. nana) and note similarities to E. sosorum. Adult E. rathbunilack major histological features associated with vision; however, eye morphology did not differ significantly between E. rathbuniand E. sosorumin early developmental stages, suggesting a combination of underdevelopment and degeneration contribute to the reduced eyes of adult E. rathbuni.

scholarly journals Corrigenda: New occurrence records for stygobiontic invertebrates from the Edwards and Trinity aquifers in west-central Texas, USA. Subterranean Biology 28: 1–13. https://doi.org/10.3897/subtbiol.28.29282

2019 ◽  
Vol 31 ◽  
pp. 49-51
Author(s):  
Bradley D. Nissen ◽  
Thomas J. Devitt ◽  
Nathan F. Bendik ◽  
Andrew G. Gluesenkamp ◽  
Randy Gibson
Keyword(s):  
Data Center ◽  
State University ◽  
Edwards Aquifer ◽  
University Of Texas ◽  
Other Information ◽  
San Marcos ◽  
Correct Table ◽  
Central Texas ◽  
The University ◽  
Occurrence Records

It has come to our attention that in Table 2, four records of Cirolanides sp. were mistakenly labeled as having been catalogued in the University of Texas Insect Collections (UTIC), when in fact they are catalogued in the Aquifer Biology Collection at the Edwards Aquifer Research and Data Center at Texas State University, San Marcos, Texas. All other information about the specimens is correct. The CORRECT Table is as follows:

Intersexual social behavior of urban white-tailed deer and its evolutionary implications

2007 ◽  
Vol 85 (7) ◽  
pp. 759-766 ◽  
Author(s):  
Katherine E. Richardson ◽  
Floyd W. Weckerly
Keyword(s):  
Social Behavior ◽  
Predation Risk ◽  
Group Size ◽  
Social Factor ◽  
Size Composition ◽  
Urban Environments ◽  
Focal Animal ◽  
The Social ◽  
San Marcos ◽  
Central Texas

White-tailed deer ( Odocoileus virginianus (Zimmermann, 1780)) are now common in many urban environments throughout their geographic range. Yet, how male and female deer in the urban environment associate, behave socially, and the evolutionary implications of that behavior remains unstudied. We examined predictions of the predation risk and the social factor hypotheses to explain intersexual grouping patterns and social behavior observed in white-tailed deer inhabiting the small city of San Marcos (population size ~45 000) in central Texas. Two routes were surveyed weekly from a vehicle at dawn and dusk for 1 year. Group size, composition, distance to vehicle, and alarm state of deer to the vehicle were recorded. Focal animal sampling was used to measure the time males and females spent and number of aggressions within one body length of each other when in groups. Female-only groups were most prevalent year round followed by mixed-sex groups, which increased in prevalence in summer and during the mating season. Alarm state was weakly related to group size but not to group composition. Males were farther apart and more aggressive than females in groups. Proportion of males in mixed-sex groups declined with increased group size. Intersexual patterns of grouping and social behavior of urban deer supported the social factor hypothesis but not the predation risk hypothesis.

scholarly journals Divergent patterns of ocular development and gene expression in the evolution of a subterranean salamander

2018 ◽  
Author(s):  
Ruben U. Tovar ◽  
Valentin Cantu ◽  
Brian P. Fremaux ◽  
Pedro Gonzalez ◽  
Dana M. García
Keyword(s):  
Developmental Stages ◽  
Ocular Tissue ◽  
Ocular Development ◽  
Evolution And Development ◽  
Extreme Phenotypes ◽  
San Marcos ◽  
Central Texas ◽  
Lens Vesicle ◽  
Surface Dwelling ◽  
Salamander Species

Relatively few studies have focused on the evolution and development of divergent nervous systems. The salamander clade (Eurycea) from the karst regions of central Texas provide an ideal platform for comparing divergent nervous and sensory systems, since some species exhibit extreme phenotypes thought to be associated with inhabiting a subterranean environment, including highly reduced eyes. We describe ocular development and examine early ocular protein expression (Pax6 and Shh), comparing between two salamander species representing two phenotypes: the surface dwelling Barton Springs salamander (E. sosorum) and the obligate subterranean Texas blind salamander (E. rathbuni). Between the two species, similarities during the development of ocular tissue (e.g. optic cup and lens vesicle) were observed during embryogenesis. However, during late stage embryogenesis the two species display markedly different patterns of Pax6 localization, which parallel patterns previously reported in a cavefish. A lens vesicle was observed in E. rathbuniembryos at stage 40, yet the lens is absent in adults, suggesting the regression of the lens during ontogeny. We also include adult histology of the surface dwelling San Marcos salamander (E. nana) and note similarities to E. sosorum. Adult E. rathbunilack major histological features associated with vision; however, eye morphology did not differ significantly between E. rathbuniand E. sosorumin early developmental stages, suggesting a combination of underdevelopment and degeneration contribute to the reduced eyes of adult E. rathbuni.

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