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A new maximum body size record for the Berry Cave Salamander (Gyrinophilus gulolineatus) and genus Gyrinophilus (Caudata, Plethodontidae) with a comment on body size in plethodontid salamanders

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Lungless salamanders in the family Plethodontidae exhibit an impressive array of life history strategies and occur in a diversity of habitats, including caves. However, relationships between life history, habitat, and body size remain largely unresolved. During an ongoing study on the demography and life history of the paedomorphic, cave-obligate Berry Cave Salamander (Gyrinophilus gulolineatus, Brandon 1965), we discovered an exceptionally large individual from the type locality, Berry Cave, Roane County, Tennessee, USA. This salamander measured 145 mm in body length and represents not only the largest G. gulolineatus and Gyrinophilus ever reported, but also the largest plethodontid salamander in the United States. We discuss large body size in G. gulolineatus and compare body size in other large plethodontid salamanders in relation to life history and habitat.
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A new maximum body size record for the Berry Cave Salamander... 29
A new maximum body size record for the Berry
Cave Salamander (Gyrinophilus gulolineatus) and
genus Gyrinophilus (Caudata, Plethodontidae) with a
comment on body size in plethodontid salamanders
Nicholas S. Gladstone1, Evin T. Carter2, K. Denise Kendall Niemiller3,
Lindsey E. Hayter4, Matthew L. Niemiller3
1 Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee 37916, USA
2Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37916, USA
3 Department of Biological Sciences, e University of Alabama in Huntsville, Huntsville, Alabama 35899,
USA 4 Admiral Veterinary Hospital, 204 North Watt Road, Knoxville, Tennessee 37934, USA
Corresponding author: Matthew L. Niemiller (
Academic editor: O. Moldovan|Received 12 October 2018|Accepted 23 October 2018|Published 16 November2018
Citation: Gladstone NS, Carter ET, Niemiller KDK, Hayter LE, Niemiller ML (2018) A new maximum body size
record for the Berry Cave Salamander (Gyrinophilus gulolineatus) and genus Gyrinophilus (Caudata, Plethodontidae)
with a comment on body size in plethodontid salamanders. Subterranean Biology 28: 29–38.
Lungless salamanders in the family Plethodontidae exhibit an impressive array of life history strategies
and occur in a diversity of habitats, including caves. However, relationships between life history, habitat,
and body size remain largely unresolved. During an ongoing study on the demography and life history of
the paedomorphic, cave-obligate Berry Cave Salamander (Gyrinophilus gulolineatus, Brandon 1965), we
discovered an exceptionally large individual from the type locality, Berry Cave, Roane County, Tennessee,
USA. is salamander measured 145 mm in body length and represents not only the largest G. gulolinea-
tus and Gyrinophilus ever reported, but also the largest plethodontid salamander in the United States. We
discuss large body size in G. gulolineatus and compare body size in other large plethodontid salamanders
in relation to life history and habitat.
amphibian, habitat, life history, paedomorphosis, subterranean
Subterranean Biology 28: 29–38 (2018)
doi: 10.3897/subtbiol.28.30506
Copyright Nicholas S. Gladstone et al. This is an open access article distributed under the terms of the Creative Commons Attribution License
(CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Biology Published by
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for Subterranean Biology
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Nicholas S. Gladstone et al. / Subterranean Biology 28: 29–38 (2018)
Body size in amphibians is driven by strong selective pressures, because it interacts with
many aspects of life history (Whitford and Hutchison 1967, Blueweiss et al. 1978,
Hairston and Hairston 1987, Stearns 1992). Although several ecological and evolution-
ary mechanisms can be responsible for body size variation in amphibians, overarching
patterns are elusive (e.g., Bernardo and Reagan-Wallin 2002, Adams and Church 2008,
Slavenko and Meiri 2015). In response to Tilley and Bernardo (1993), Beachy (1995)
argues that a primary inuence on body size in amphibians is a delay in larval and juve-
nile period. In general, K-selected characteristics are correlated with increased longevity
and a shift toward larger propagule size in stable environments. Prolonged developmen-
tal periods may promote neoteny (or prolonged maturation) and can be associated with
reduced energy demand (McNamara and McNamara 1997). is suggests a possible
correlation between increased body size and both paedomorphic and K-selected life his-
tory strategies. However, the relationship between amphibian body size and these life
history strategies is largely unresolved (Yeh 2002, Wiens and Hoverman 2008).
While the reduction of body can be associated with paedomorphic traits (e.g.,
Alberch and Alberch 1981, Yeh 2002), Wiens and Hoverman (2008) concluded that
obligately paedomorphic salamanders (Amphiumidae, Cryptobranchidae, Proteidae,
Sirenidae) exhibit larger body sizes compared to those within clades that undergo met-
amorphosis. is pattern does not seem to translate to paedomorphic species within
clades that possess metamorphic or direct-developing species (Wiens and Hoverman
2008). In fact, paedomorphic Eurycea (Plethodontidae) associated with springs and
caves of the Edward’s Plateau in Texas are characterized by reduced body size relative
to their obligately metamorphic congeners, while both metamorphic and paedomor-
phic Ambystoma (Ambystomatidae) share similar body size (Ryan and Bruce 2000,
AmphibiaWeb 2018).
Caves and other subterranean habitats are often viewed as extreme and inhospitable
environments characterized by an absence of primary production and limited resources
(Culver and Pipan 2009). Salamanders are one of only two vertebrate groups to have
successfully colonized and obligately live in subterranean habitats. Fourteen species
from two families (Plethodontidae and Proteidae) occur exclusively in caves, and most
have evolved paedomorphosis (Goricki et al. 2012, in press, Niemiller et al. unpubl.
data), which may be a response to limited food resources within terrestrial cave habitats
(Brandon 1971, Wilbur and Collins 1973, Ryan and Bruce 2000). Few studies have ex-
amined the relationship between cave inhabitation and body size, and changes in body
size may not necessarily be associated with shifts from surface to subterranean habitats
(Romero 2009, Pipan and Culver 2017). However, many cave-obligate species (i.e.,
troglobites) exhibit K-selected life history traits such as reduced growth rate, delayed
sexual maturity, and increased longevity (Brandon 1971, Culver and Pipan 2009, Hüp-
pop 2012), and some troglobites and stygobites are larger than their surface congeners,
such as in amblyopsid caveshes (Poulson 1963, 1985, Niemiller and Poulson 2010).
A new maximum body size record for the Berry Cave Salamander... 31
e plethodontid genus Gyrinophilus Cope, 1869 includes four semi-aquatic to
paedomorphic species endemic to the highlands of eastern North America. ree spe-
cies are paedomorphic stygobionts found in caves of the Interior Low Plateau and
Appalachians karst regions of Alabama, Tennessee, Georgia, and West Virginia in the
United States (Niemiller et al. 2009, Goricki et al. 2012). Here, we report on a Berry
Cave Salamander, G. gulolineatus Brandon, 1965, from the type locality in Roane Co.,
Tennessee that exceeds the current maximum body size record for the species and rep-
resents the largest Gyrinophilus and plethodontid salamander reported in the United
States. Gyrinophilus gulolineatus is known from just ten localities in the Clinch and
Tennessee River watersheds in the Appalachians karst region of eastern Tennessee (Fig-
ure 1). e largest G. gulolineatus previously reported measured 136 mm snout-vent
length (SVL; tip of the snout to the posterior margin of the vent) from the type locality
(Brandon 1965, 1966).
As part of an ongoing study on the demography and life history of Gyrinophilus gulo-
lineatus, we captured a large G. gulolineatus at the type locality, Berry Cave (Tennessee
Cave Survey no. TRN3), on 12 August 2018. Berry Cave is located 0.37 km west of
the Tennessee River near Wright Bend in Roane County, Tennessee. e main entrance
is in a large sink, with the passage from the entrance steeply sloping down to the main
stream passage. e passage can be followed downstream to the northeast for ~160m
along the stream until large debris and sediment buildup block further exploration.
e stream is characterized by a series of ries and shallow (<0.5 m) pools with pri-
marily chert, cobble, and coarse gravel substrate and signicant amounts of coarse
woody debris, detritus, and ne mud and sediment in some areas. e salamander was
observed and captured in the margin of a shallow (<0.5 m deep) pool located in a small
passage upstream from the main entrance chamber. When rst encountered, all but
the salamander’s head was out of the water, as it appeared to be moving partially over
land to continue upstream.
e salamander was captured with a handheld dip net and immediately trans-
ferred to a clear plastic bag for processing. We massed to the nearest 0.5 g using a
Pesola® spring scale and measured to the nearest 0.5 mm snout-vent length (SVL; tip
of the snout to the posterior margin of the vent) and total length (TL; tip of the snout
to the end of the tail) using a metric caliper. e salamander was measured four times
by MLN, conrmed by NSG and ETC, and then photographed using an Olympus
Tough TG-5 Camera. We also noted any physical abnormalities and the overall health
of the salamander. Finally, we marked the salamander by injecting a 1.2 × 2.7 mm
visible implant (VI) alpha tag (Northwest Marine Technology Inc., Shaw Island, WA)
into the dermis of the tail. e salamander was released at its point of capture follow-
ing processing.
Nicholas S. Gladstone et al. / Subterranean Biology 28: 29–38 (2018)
Figure 1. Geographic distribution of the Berry Cave Salamander (Gyrinophilus gulolineatus) in relation
to karst adapted from Weary and Doctor (2014). Blue circles represent cave localities from which the spe-
cies has been reported, and the red star represents the location of Berry Cave. e top right image shows
the main stream passage near the entrance of Berry Cave that continues throughout the entirety of our
sampling area. e bottom right image shows the large individual captured on 12 August 2018. Photo
credits: Matthew L. Niemiller.
To provide a comparison of body size relations across other large-bodied pletho-
dontids, we later compiled a list of maximum body sizes, modes of development, and
habitat for several plethodontid salamanders by conducting a search of the primary
literature and relevant eld guides (see Table 1 and references therein).
e Gyrinophilus gulolineatus observed and captured at Berry Cave on 12 August 2018
measured 145 mm SVL and 238 mm TL, with a mass of 35 g (Figure 2). Head width
measured 22 mm. ere was notable damage to the posterior end of the tail, and it is
likely that this individual was >250 mm TL before tail tissue loss. Additionally, the two
distal-most gill rachises on the right side of the head were notably smaller than those
on the left side, while the most proximal right gill rachis was enlarged relative to that
on the left side of the head.
A list of maximum body size and total length for several large plethodontid
salamanders is reported in Table 1. Based on our literature review, G. gulolineatus
is the largest plethodontid based on body size (SVL) in the United States, while
A new maximum body size record for the Berry Cave Salamander... 33
Table 1. Mode of development (DD = direct development, m = metamorphic; OP = obligately paedo-
morphic, FP = facultatively paedomorphic), habitat (AQC = aquatic cave, SAC = semi-aquatic cave, SAT
= semiaquatic terrestrial, SUT = surface terrestrial), maximum body size (SVL) and total length (TL) of
select plethodontid salamanders based on literature sources and the current study.
Size and life history characteristics of select plethodontid salamanders
Species Mode of
development Habitat SVL (mm) TL (mm) References
Bolitoglossa doeini DD SUT 130 205 Feder et al. (1982)
Desmognathus quadramaculatus MSAT 103 189 Bakkegard and Rhea (2012)
Gyrinophilus gulolineatus OP AQC 145 238 Brandon (1965, 1966), this study
Gyrinophilus palleucus OP AQC 113 186 Lazell and Brandon (1962), Dent and Kirby-
Smith (1963), Niemiller et al. (unpubl. data)
Gyrinophilus porphyriticus MSAT/
SAC 134 221 Brandon (1966), Niemiller et al. (2010),
Niemiller et al. (unpublished data)
Gyrinophilus subterraneus FP SAC 117 199 Niemiller et al. (2010)
Isthmura bellii DD SUT 146 327 Smith (1949), Feder et al. (1982),
Isthmura gigantea DD SUT 161 276 Taylor and Smith (1945)
Isthmura maxima DD SUT 128 244 Parra-Olea et al. (2005)
Phaeognathus hubrichti DD SUT 138 268 Schwaner and Mount (1970), Bakkegard and
Guyer (2004), Graham et al. (2009)
Figure 2. Dorsal view of the Gyrinophilus gulolineatus captured at Berry Cave. Photo credit: Matthew
L. Niemiller.
Nicholas S. Gladstone et al. / Subterranean Biology 28: 29–38 (2018)
only Phaeognathus hubrichti attains a greater total length. Body size in G. gulolin-
eatus rivals that observed in the direct-developing Isthmura bellii species complex
endemic to Mexico.
Plethodontid salamanders exhibit considerable variation in life history strategies and
habitat that has resulted in an extraordinary range of growth rates and age at maturity
(Tilley and Bernardo 1993, Beachy 1995, Beachy et al. 2017). Representative species
with notable larger body sizes included in Table 1 represent four primary modes of
development in salamanders, with paedomorphic and direct-developing species ex-
hibiting larger body sizes relative to metamorphosing species. Larger species also are
correlated with aquatic habitats, apart from the Isthmura bellii species complex, which
inhabits Neotropical montane forests in southern North America.
Larger plethodontids are likely to occur in well-oxygenated, moist to fully aquat-
ic habitats, which largely relax allometric constraints on gas exchange. is is par-
ticularly relevant to those species that exhibit paedomorphic life history strategies.
Paedomorphic individuals may be able to grow unimpeded in their permanently
aquatic state owing to indeterminate growth. Obligate paedomorphosis has evolved
multiple times within Plethodontidae, with the subfamily Spelerpinae having the
greatest richness of paedomorphic species (Chippendale 1995; Ryan and Bruce
2000; Bonnet et al. 2014). Additionally, neoteny has been predicted to be the pri-
mary causal mechanism of paedomorphosis in salamanders (Duellman and Trueb
1986, Ryan and Bruce 2000). Larger amphibian body sizes are further associated
with longer juvenile periods, which signicantly covary with age at maturation (e.g.,
Desmognathus quadramaculatus and Gyrinophilus porphyriticus, Bruce 1988, Beachy
1995, Beachy et al. 2017).
Many of the largest plethodontid salamanders are direct-developing (e.g., Phae-
ognathus hubrichti in the United States; Isthmura bellii in Mexico). Direct-developing
species are generally characterized by having larger eggs and longer embryonic devel-
opment relative to metamorphic or paedomorphic species, and this may related to
attaining larger body sizes (Wake and Hanken 2004). ere are, however, tradeos
related to larger body size in these terrestrial plethodontids. e habitat must sup-
port gas exchange through adequate temperature and moisture gradients, and these
taxa have evolved physiological mechanisms, such as waxy secretions, to reduce water
loss. Second, terrestrial environments typically have lower food availability, and, ac-
cordingly, terrestrial salamanders often experience more extended periods of inactivity
(Jaeger 1979, 1981, Scott et al. 2007). Phaeognathus, for instance, has rarely (if ever)
been observed outside of burrows in densely forested ravines. Larger body size in such
species is in accordance with the ‘starvation hypothesis’ that predicts that greater mass
is positively correlated to seasonality and periods of low resource availability (Lundberg
1986), because larger individuals can persist through low-resource events by having
A new maximum body size record for the Berry Cave Salamander... 35
greater energy stores and typically more ecient metabolism owing to positive allom-
etry. e starvation hypothesis has received recent support in multiple amphibian taxa,
where body size is positively related to extended inactivity (Valenzuela-Sánchez et al.
2015) and increased precipitation seasonality (Goldberg et al. 2018).
Cave environments are often characterized by low food resources and few natu-
ral predators, which likely shaped much of the evolution of many subterranean taxa
(Gibert and Deharveng 2002). However, this archetype may not be representative of
all subterranean systems, as many caves possess a high surface-environment connec-
tion with signicant allochthonous organic input (i.e., higher inux of organic matter)
driving both terrestrial and aquatic food webs. Cave obligate salamanders often exhibit
reduced growth rates and low metabolic demand (e.g., Hervant et al. 2000), and they
may also exhibit greater longevity owing to the slow pace of life and low predation
pressure associated with subterranean environments (Brandon 1971, Culver and Pipan
2009, Voituron et al. 2011, Hüppop 2012). High resource environments may thus
permit more rapid growth and sustain a larger overall body size. e exceptionally large
Gyrinophilus gulolineatus reported here occurred within 10 m of the cave entrance in
a high ow zone with an abundance of organic matter accumulated in the cave pool.
Berry Cave is a diverse system relative to other caves in the Appalachian Valley and
Ridge (Niemiller et al. 2016), likely due to the large inux of organic matter from the
surface.ere are a variety of invertebrate taxa that serve as prey for G. gulolineatus
(e.g., isopods, amphipods, craysh, atworms, etc.).
While there has been much focus on life history evolution in salamanders, sam-
pling biases may impact interpretations of the relationship between body size and
mode of development. Paedomorphic species may be more dicult to capture, and
they are often associated with extreme habitats such as underground springs and caves
(Ryan and Bruce 2000, Bonnet et al. 2014). More thorough survey eorts and detailed
life history observations within harsher or more isolated environments are necessary to
better understand how paedomorphosis may relate to body size in amphibians.
Due to its subterranean existence and cryptic nature, many life history characteris-
tics of G. gulolineatus have yet to be documented. Active survey eorts are continuing to
assess the species’ demography in Berry Cave, as well as to better understand the growth
of this species. Further biological inventory within the Appalachian Valley and Ridge is
underway with the intent to uncover additional localities. Future directions for research
include additional life history characterization and study of the species’ ecology.
Funding for this project was provided by the U.S. Fish & Wildlife Service (grant no.
F17AC00939). All research was conducted under a TWRA scientic collection per-
mit (nos. 1385 and 1605) and following an approved protocol by the University of
Alabama in Huntsville Institutional Animal Care and Use Committee (protocol no.
2017.R005). We especially thank the Healy family for allowing access to Berry Cave.
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... On the other hand, Proteus has inherited its aquatic and darkness-loving habits from surface ancestors. Likewise, it has inherited its large body reaching close to 0.1 kilogram, which is about an order of magnitude above the mass of most North American cave salamanders but comparable to the size of the largest known individuals of the Berry Cave salamander (Gyrinophilus gulolineatus; Gladstone et al. 2018). Sustaining a body of this size seems to be in conflict with the energy-poor subterranean ecosystem. ...
... Sustaining a body of this size seems to be in conflict with the energy-poor subterranean ecosystem. A possible explanation lies in the biological richness of some subterranean waters of the Dinaric Karst that are home to Proteus, and in the high organic input from the surface in the Berry Cave (Gladstone et al. 2018). ...
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Throughout most of the kingdom Animalia, evolutionary transitions from surface life to a life permanently bound to caves and other subterranean habitats have occurred innumerous times. Not so in tetrapods, where a mere 14 cave-obligate species—all plethodontid and proteid salamanders—are known. We discuss why cave tetrapods are so exceptional and why only salamanders have made the transition. Their evolution follows predictable and convergent, albeit independent pathways. Among the many known changes associated with transitions to subterranean life, eye degeneration, starvation resistance, and longevity are especially relevant to human biomedical research. Recently, sequences of salamander genomes have become available opening up genomic research for cave tetrapods. We discuss new genomic methods that can spur our understanding of the evolutionary mechanisms behind convergent phenotypic change, the relative roles of selective and neutral evolution, cryptic species diversity, and data relevant for conservation such as effective population size and demography.
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Variation in body size represents one of the crucial raw materials for evolution. However, at present, it is still being debated what is the main factor affecting body size or if the final body size is the consequence of several factors acting synergistically. To evaluate this, widespread species seem to be suitable models because the different populations occur along a geographical gradient and under contrasted climatic and environmental conditions. Here we describe the spatial pattern of variation in body size and sexual size dimorphism in the snouted treefrog Scinax fuscovarius (Anura, Hylidae) along a 10° range in latitude, 25° longitude, and 2000 m in altitude from Argentina, Brazil and Paraguay using an information-theoretic approach to evaluate the support of the data for eight a priori hypotheses proposed in the literature to account for geographical body size, and three hypotheses for sexual size dimorphism variation. Body size of S. fuscovarius varied most dramatically with longitude and less so with latitude; frogs were largest in the northwestern populations. Body size was positively related with precipitation seasonality, and negatively with annual precipitation. Furthermore, the degree of sexual size dimor-phism was greatest in the western populations with less annual precipitation, as the increase in body size was stronger for females. Our results on body size variation are consistent with two ecogeographical hypotheses, the starvation resistance and the water availability hypotheses, while our results on sexual size dimorphism in S. fus-covarius supports the differential-plasticity hypothesis but the inverse to Rensch's rule and the parental investment hypothesis. Due to the weak association between environmental variables and body size and sexual size dimorphism variation, we stress that there are other factors, mainly those related to the life history, driving the geographical variation of S. fuscovarius.
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Plethodontid salamanders exhibit biphasic, larval form paedomorphic, and direct developing life cycles. This diversity of developmental strategies exceeds that of any other family of terrestrial vertebrate. Here we compare patterns of larval development among the three divergent lineages of biphasic plethodontids and other salamanders. We discuss how patterns of life-cycle evolution and larval ecology might have produced a wide array of larval life histories. Compared with many other salamanders, most larval plethodontids have relatively slow growth rates and sometimes exceptionally long larval periods (up to 60 mo). Recent phylogenetic analyses of life-cycle evolution indicate that ancestral plethodontids were likely direct developers. If true, then biphasic and paedomorphic lineages might have been independently derived through different developmental mechanisms. Furthermore, biphasic plethodontids largely colonized stream habitats, which tend to have lower productivity than seasonally ephemeral ponds. Consistent with this, plethodontid larvae grow very slowly, and metamorphic timing does not appear to be strongly affected by growth history. On the basis of this, we speculate that feeding schedules and stress hormones might play a comparatively reduced role in governing the timing of metamorphosis of stream-dwelling salamanders, particularly plethodontids.
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variety of subterranean habitats share an absence of light and a dependence on allochthonous productivity, but they differ in many features, including habitat volume. We examined the hypothesis that habitat volume is an important factor in community organization, especially with reference to body size, for a variety of communities for which data were available. We analyzed the results of ten studies that compared body sizes of obligate subterranean dwelling species with respect to habitat. All of the studies confirmed the hypothesis that habitat size was an important determinant of body size. However, surprisingly little information is available on the relationship between body size and habitat size, and only two of the studies reported directly on the size of habitat spaces. Habitat size appears to be an important determinant of body size in subterranean species, but more detailed studies, especially of habitat (pore) size are needed. © 2017, National Speleological Society Inc. All rights reserved.
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More than one-fifth of the documented caves in the United States occur in Tennessee. The obligate subterranean biota of Tennessee is rich and diverse, with 200 troglobionts reported from over 660 caves. Fifty troglobionts are known from just 75 of the 1,469 caves in the Appalachian Valley and Ridge physiographic province of eastern Tennessee. Tennessee’s Valley and Ridge has been under-sampled relative to other karst areas in the state, limiting our knowledge of cave and karst species diversity and distributions and compromising our ability to identify habitats and species potentially at risk from anthropogenic threats, such as urban sprawl near the metropolitan area of Knoxville. Knowledge of nontroglobiontic species inhabiting caves, including vertebrates, is particularly sparse in this region. Although caves have long been recognized as critical habitats for several bat species, the importance of caves for other vertebrate taxa has received less attention. Caves are important habitats for many other nontroglobiontic vertebrates and should be considered in the management and conservation of these species. Our decade-long study bioinventoried 56 caves in 15 counties and begins to address knowledge gaps in distributions and cave use by vertebrates in the Valley and Ridge and adjacent Blue Ridge Mountains of eastern Tennessee within the Appalachians karst region. In addition, we conducted a thorough review of the literature and museum databases for additional species-occurrence records in those provinces of eastern Tennessee. From these sources, we present an annotated list of 54 vertebrate taxa, including 8 fishes, 19 amphibians (8 anurans and 11 salamanders), 6 reptiles, 3 birds, and 18 mammals. Three species are included on the IUCN Red List of Threatened Species, while six species are at risk of extinction based on NatureServe conservation rank criteria. Ten bat species are known from 109 caves in 24 eastern Tennessee counties. Our bioinventories documented five bat species in 39 caves, including new records of the federally endangered Gray Bat (Myotis grisescens). We observed visible evidence of whitenose syndrome caused by the fungal pathogen Pseudogymnoascus destructans at four caves in Blount, Roane, and Union counties. We documented two new localities of the only troglobiontic vertebrate in the Valley and Ridge, the Berry Cave Salamander (Gyrinophilus gulolineatus). Despite these efforts, significant sampling gaps remain-only 7.7% of known caves in the Valley and Ridge and Blue Ridge Mountains of eastern Tennessee have records of vertebrate-species occurrence. Moreover, few caves in eastern Tennessee have experienced repeated, comprehensive bioinventories, with the exception of periodic surveys of hibernating bats at selected caves. Future bioinventory efforts should incorporate multiple visits to individual caves, if possible, and more efforts should focus on these understudied areas of eastern Tennessee. © 2016, National Speleological Society Inc. All right reserved.
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The tribe Hemidactyliini (Caudata: Plethodontidae: Plethodontinae) is a morphologically conservative taxon, comprising about 25 species distributed over eight genera (Conant and Collins, 1998). Despite significant attention over the last 30 years, there are many problems regarding the phylogeny and taxonomy of the Hemidactyliini. Wake (1966, 1993) has questioned the monophyly of this group, and recent phylogenetic analyses have failed to resolve the question (e.g., Rose, 1995; Sever, 1994). Hemidactyliines are relatively generalized salamanders, lacking the degree of morphological specialization found in the other three plethodontid lineages; e.g., the skeletomuscular adaptations for feeding and burrowing of the desmognathines (Schwenk and Wake, 1993), the specializations of the tongue projection mechanism of bolitoglossines (Deban et al., 1997; Lombard and Wake, 1977), and the derived morpho-genetic features associated with direct development in both bolitoglossines and plethodontines (Collazo and Marks, 1994). Furthermore, all hemidactyliines have a larval stage and the majority exhibit a complex life cycle (Wilbur, 1980), and thus differ from the other members of the subfamily Plethodontinae, their closest relatives. A complex life cycle is considered ancestral for the family Plethodontidae and is shared with most members of the subfamily Desmognathinae (Wake, 1966).
Caves and other subterranean habitats with their often strange (even bizarre) inhabitants have long been objects of fascination, curiosity, and debate. The question of how such organisms have evolved, and the relative roles of natural selection and genetic drift, has engaged subterranean biologists for decades. Indeed, these studies continue to inform the general theory of adaptation and evolution. Subterranean ecosystems generally exhibit little or no primary productivity and, as extreme ecosystems, provide general insights into ecosystem function. The Biology of Caves and other Subterranean Habitats offers a concise but comprehensive introduction to cave ecology and evolution. Whilst there is an emphasis on biological processes occurring in these unique environments, conservation and management aspects are also considered. The monograph includes a global range of examples from more than 25 countries, and case studies from both caves and non-cave subterranean habitats; it also provides a clear explanation of specialized terms used by speleologists. This accessible text will appeal to researchers new to the field and to the many professional ecologists and conservation practitioners requiring a concise but authoritative overview. Its engaging style will also make it suitable for undergraduate and graduate students taking courses in cave and subterranean biology. Its more than 650 references, 150 of which are new since the first edition, provide many entry points to the research literature.