Abyssal Ambushers

Field researcher and passionate conservationist Dante Fenolio reports on the DEEPEND project taking place int hte waters of the Gulf of Mexico

Hiding in Plain Sight: Elopomorph Larvae Are Important Contributors to Fish Biodiversity in a Low-Latitude Oceanic Ecosystem

Leptocephalus larvae of elopomorph fishes are a cryptic component of fish diversity in nearshore and oceanic habitats. However, identifying those leptocephali can be important in illuminating species richness in a region. Since the Deepwater Horizon oil spill in 2010, sampling of offshore fishes in the epi-, meso-, and upper bathypelagic depth strata of the northern Gulf of Mexico resulted in 8989 identifiable specimens of leptocephalus larvae or transforming juveniles, in 118 taxa representing 83 recognized and established species and an additional 35 distinctive leptocephalus morphotypes not yet linked to a known described species. Leptocephali account for ∼13% of the total species richness of fishes collected in the offshore region. A new morphotype of Muraenidae leptocephalus is also described. We compare this study with other leptocephalus diversity studies in the western Atlantic

Conservation status of the Georgia Blind Salamander (Eurycea wallacei) from the Floridan Aquifer of Florida and Georgia

The Georgia Blind Salamander (Eurycea wallacei) is a poorly understood stygobitic plethodontid salamander found in the Floridan Aquifer of Florida and Georgia, USA. Its distribution is poorly delimited and little information is available on the ecology and life history of the species. We summarize existing information on the Georgia Blind Salamander and report new findings with regard to distribution, conservation status, and aspects of its ecology and life history from recent surveys in Florida and Georgia, including anecdotal observations made by local cave divers. We also  present data on the prevalence of Batrachochytrium dendrobatidis and discuss potential measures and challenges involved in conservation. Georgia Blind Salamanders are known from at least 35 localities within five United States Geological Survey (USGS) HUC8 watersheds in Florida and Georgia, all within the groundwater of the Upper Floridan Aquifer. Some populations may be large, as cave divers have observed >100 salamanders in a single dive at three localities and reported densities up to 10 salamanders per square meter. We confirm through direct observation that the Dougherty Plain Cave Crayfish (Cambarus cryptodytes) is a predator of E. wallacei. Although we found no evidence that any populations of the Georgia Blind Salamander have been infected by amphibian chytrid fungus, clear threats remain and include: (1) An “at risk” ranking by USGS of the Floridian Aquifer for contamination; (2) overharvesting of groundwater; (3) the presence of an emergent infectious amphibian disease in surface amphibians in the region (e.g., amphibian chytrid fun- gus); and (4) a lack of data on the basic biology and ecology of the species. We recommend the following conservation actions: (1) Better regulations and improved methods for retaining pesticide and fertilizer contaminants on the surface; (2) regulatory review of agricultural crops grown in the region and the establishment of systems and crops that do not require center pivot irrigation; (3) regular monitoring for disease across the range of the species; and (4) establishment of multiple assurance colonies such that captive specimens genetically represent at least half of the known populations

Ongoing Transposon-Mediated Genome Reduction in the Luminous Bacterial Symbionts of Deep-Sea Ceratioid Anglerfishes

Diverse marine fish and squid form symbiotic associations with extracellular bioluminescent bacteria. These symbionts are typically free-living bacteria with large genomes, but one known lineage of symbionts has undergone genomic reduction and evolution of host dependence. It is not known why distinct evolutionary trajectories have occurred among different luminous symbionts, and not all known lineages previously had genome sequences available. In order to better understand patterns of evolution across diverse bioluminescent symbionts, we de novo sequenced the genomes of bacteria from a poorly studied interaction, the extracellular symbionts from the “lures” of deep-sea ceratioid anglerfishes. Deep-sea anglerfish symbiont genomes are reduced in size by about 50% compared to free-living relatives. They show a striking convergence of genome reduction and loss of metabolic capabilities with a distinct lineage of obligately host-dependent luminous symbionts. These losses include reductions in amino acid synthesis pathways and abilities to utilize diverse sugars. However, the symbiont genomes have retained a number of categories of genes predicted to be useful only outside the host, such as those involved in chemotaxis and motility, suggesting that they may persist in the environment. These genomes contain very high numbers of pseudogenes and show massive expansions of transposable elements, with transposases accounting for 28 and 31% of coding sequences in the symbiont genomes. Transposon expansions appear to have occurred at different times in each symbiont lineage, indicating either independent evolutions of reduction or symbiont replacement. These results suggest ongoing genomic reduction in extracellular luminous symbionts that is facilitated by transposon proliferations

Diverse deep-sea anglerfishes share a genetically reduced luminous symbiont that is acquired from the environment

Deep-sea anglerfishes are relatively abundant and diverse, but their luminescent bacterial symbionts remain enigmatic. The genomes of two symbiont species have qualities common to vertically transmitted, host-dependent bacteria. However, a number of traits suggest that these symbionts may be environmentally acquired. To determine how anglerfish symbionts are transmitted, we analyzed bacteria-host codivergence across six diverse anglerfish genera. Most of the anglerfish species surveyed shared a common species of symbiont. Only one other symbiont species was found, which had a specific relationship with one anglerfish species, Cryptopsaras couesii. Host and symbiont phylogenies lacked congruence, and there was no statistical support for codivergence broadly. We also recovered symbiont-specific gene sequences from water collected near hosts, suggesting environmental persistence of symbionts. Based on these results we conclude that diverse anglerfishes share symbionts that are acquired from the environment, and that these bacteria have undergone extreme genome reduction although they are not vertically transmitted

Characterization of the microbiome and bioluminescent symbionts across life stages of ceratioid anglerfishes of the gulf of mexico

The interdependence of diverse organisms through symbiosis reaches even the deepest parts of the oceans. As part of the DEEPEND project (deependconsortium.org) research on deep Gulf of Mexico biodiversity, we profiled the bacterial communities (‘microbiomes’) and luminous symbionts of 36 specimens of adult and larval deep-sea anglerfishes of the suborder Ceratioidei using 16S rDNA. Transmission Electron Microscopy was used to characterize the location of symbionts in adult light organs (esca). Whole larval microbiomes, and adult skin and gut microbiomes, were dominated by bacteria in the genera Moritella and Pseudoalteromonas genera. 16S rDNA sequencing results from adult fishes corroborate the previously published identity of ceratioid bioluminescent symbionts and support findings that these symbionts do not consistently exhibit host specificity at the host family level. Bioluminescent symbiont amplicon sequence variants (ASVs) were absent from larval ceratioid samples, but were found at all depths in the seawater, with a highest abundance found at mesopelagic depths. As adults spend the majority of their lives in the meso and bathypelagic, the trend in symbiont abundance is consistent with their life history. These findings support the hypothesis that bioluminescent symbionts are not present throughout host development, and that ceratioids acquire their bioluminescent symbionts from the environment

Conservation Status and Habitat Use of the West Virginia Spring Salamander (Gyrinophilus Subterraneus) and Spring Salamander (G. Porphyriticus) in General Davis Cave, Greenbrier Co., West Virginia

The West Virginia Spring Salamander (Gyrinophilus subterraneus) is one of four obligate cave-dwelling species of plethodontid salamanders found east of the Mississippi River in the United States. This species is endemic to a single cave system; General Davis Cave, in Greenbrier Co., West Virginia, where it is syntopic with the closely-related Spring Salamander (G. porphyriticus). Accordingly, the West Virginia Spring Salamander is a species of critical conservation concern. Because of it\u27s conservation status and lack of data regarding the ecology and life history, particularly about population trends, we present data on relative abundance of and habitat use by the West Virginia Spring Salamander during a 33-year period from 1975-2008. Specifically we address: (1) stability of the population during the last 33 years; (2) variation in habitat use by life stage and between species (Spring Salamanders and West Virginia Spring Salamanders); (3) plausibility of neoteny in the West Virginia Spring Salamander; and (4) the conservation status of the West Virginia Spring Salamander. We recorded 324 observations of Gyrinophilus salamanders, of which 192 were West Virginia Spring Salamanders, within the study area during 17 surveys. While both larval and metamorphosed West Virginia Spring Salamanders were encountered, only metamorphosed Spring Salamanders were observed. West Virginia Spring Salamander larvae were encountered in pools more often than in riffle habitat. Spring Salamanders were encountered more often in terrestrial habitats versus aquatic habitats. West Virginia Spring Salamanders reach relatively large size before metamorphosing, with some individuals becoming sexual mature as larvae. It remains unknown whether any of these individuals reproduce, however. Although the populations of both species appear to be stable over the past 33 years and not in immediate danger of extinction, the West Virginia Spring Salamander is still in critical conservation concern because of it\u27s extremely restricted distribution and current threats to the cave system it resides in

Insuetophrynus acarpicus Barrio, 1970 (Anura: Rhinodermatidae): new distribution record at the edge of the Valdivian coastal range, southern Chile

We report a new locality record for the Mehuín Green Frog, Insuetophrynus acarpicus Barrio, 1970, a Critically Endangered species from southern Chile. The new locality is about 90 km southeast of the type locality and expands the known geographical distribution 40 km to the southeast. The new record confirms the presence of I. acarpicus south of the Lingue and Valdivia rivers. Our documentation demonstrates a discontinuous distribution of this frog in the Valdivian Coastal Range of Chile and intensifies the need to implement effective strategies for its conservatio

Discovery of Endangered Mexican Blindcat, Prietella phreatophila, in Texas: Implications for International Groundwater Management and Evolution of the Regional Karst Aquifer Biota

Paper presented July 15, 2017 at the annual Joint Meeting of Ichthyologists and Herpetologists in Austin, Texas, USA (http://conferences.k-state.edu/JMIH-Austin-2017/). The oral presentation of this content mentioned questions about the taxonomy and phylogenetic position of Prietella lundbergi and the only specimens attributed to P. lundbergi apart from the holotype. Since the presentation, we obtained high resolution CT scans of both the holotype and a specimen (TNHC 25767) from Cueva del Nacimiento del Río Frio, not far north of the type locality. The anatomy revealed in those CT scans suggests that these specimens represent a single species, and that P. lundbergi is only remotely related to Prietella phreatophila, which would be consistent with results of Wilcox, T.P., F.J. Garcı́a de León, Dean A. Hendrickson, and D.M. Hillis. 2004. “Convergence among Cave Catfishes: Long-Branch Attraction and a Bayesian Relative Rates Test.” Molecular Phylogenetics and Evolution 31 (3): 1101–13. doi:10.1016/j.ympev.2003.11.006). Thus, further research is in progress by Hendrickson, Lundberg, Luckenbill and Arce that may result in taxonomic revision removing P. lundbergi from Prietella.Mexican blindcat, Prietella phreatophila, described in 1954 from a cave system near the town of Múzquiz in central Coahuila state, and considered a Mexican endemic, was listed by the U.S. Fish and Wildlife Service as a foreign endangered species (protected "wherever found") in 1970. Explorations in the 1990s discovered many new localities extending nearly to the international border, and in 2016 the species was discovered in Amistad National Recreation Area (ANRA) in Texas, just north of the international border near Del Rio. Not only does the discovery support the aquifer of this fish being an internationally shared resource, but the stygobitic invertebrate biota found with the fish indicates a potentially large extent of the aquifer, and thus possibly the fish, in Texas. Invertebrate faunal connections (historic or current) extend from the Amistad Lake area of the new occurrence west into the Trans-Pecos region and east into the Edwards Aquifer of central Texas. We explore implications of this for both water management and evolutionary history of this and other blind ictalurids, and suggest that population genetic studies of both stygobitic fishes and invertebrates could help hydrogeologists better define often difficult to map aquifer extents and interconnections. While NPS is continuing to support the cave explorations of ANRA that produced the Texas discovery, we propose a broader bi-national sampling effort for both the fish and invertebrates extending well beyond the current known distribution of P. phreatophila. We also pointed out questions about phylogenetic relatedness of P. phreatophila and P. lundbergi further south, as well as the possibility of a monophyletic clade of blindcats, including those of the Edwards Aquifer, Satan and Trogloglanis. If substantiated, that evolutionary history would imply broader historic inter-aquifer connections ranging from the San Antonio area as far south as southernmost Tamaulipas. Finally, we report establishment of a small captive population of Prietella phreatophila at San Antonio Zoo for research and possibly eventual conservation applications.U.S. National Park Service; San Antonio Zoo; University of Texas at Austin College of Natural Sciences and Department of Integrative BiologyIntegrative Biolog