Introduction |
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Data acquisition for this
project, which began in 1998, is ongoing. The aim is to provide an up-to-date, companion
document to Atlas of Amphibians in Tennessee (Redmond and Scott 1996),
which is available in hard copy from the Center of Excellence for Field Biology,
Austin Peay State University, Clarksville, Tennessee, and online at
http://www.apsubiology.org/tnamphibiansatlas/. The Internet version of Atlas of Amphibians in
Tennessee has the added feature of links to photographs of species and
updates on nomenclature, taxonomy, and new distribution records that have
appeared subsequent to publication of the original document.
The online version of
Atlas of Reptiles in Tennessee
(http://www.apsubiology.org/tnreptileatlas/) was launched in 1 May 2008 with
introductory and background information, plus species accounts and distribution
maps for species in the family Viperidae. Additional species accounts were added
periodically until August 2008 when accounts for all species known to occur in
the state were completed. Members of the Viperidae (Crotalidae in some
classifications) were chosen as the first group to present because their
venomous nature is of interest to biologists and laymen alike. The Introduction
and first species account (Crotalus horridus) were posted 1 May 2008. The last species account
(Chrysemys picta complex) was uploaded
15 May 2012. Updates that add newly acquired distribution and taxonomic data are
taking place four times each year soon after publication of each quarterly issue
of Herpetological Review.
This project was guided by
the following specific objectives:
1.
Seek out occurrence records
for reptiles in Tennessee from literature sources, museum collections, and
through additional field work;
2.
Verify identifications of
museum specimens and accompanying locality data;
3.
Verify locality data from
all sources;
4.
Where possible, use GPS
coordinates to digitize locality data from all sources;
5.
Develop individual species
accounts that provide (1) an overview of state-wide
distribution, (2) a detailed distribution map that displays localities currently
considered valid for the species in Tennessee, (3) a list of museum specimens
examined listed alphabetically by counties, (4) a list of sources of literature
records listed chronologically by counties, (5) problematic and/or questionable
records, and (6) a brief discussion of conservation status in Tennessee;
6.
Disseminate the results
electronically via the Internet;
7.
Develop a hardcopy version
of the web site.
We hope the information
contained in this website will be used to further the cause of reptile
conservation in Tennessee by providing essential baseline information for
education and future research on these often-maligned creatures. Many species
have glaring gaps depicted in the mapped distributions. Our wish is that this
will encourage readers to fill these gaps by documenting and publishing new
county records.
Map Development and Presentation |
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Baseline Distribution Data
Baseline distribution data were taken from two main sources: museum collections and literature sources. Twenty-five institutions scattered throughout eastern United States (Table 1) were visited to obtain occurrence data and verify species identifications. The collection at Austin Peay State University continues to be a source of distribution data. As for information in the literature, the earliest published Tennessee reptile record was Harlan’s 1835 report of Chelonura [=Macrochelys] temminckii “from a tributary stream of the Mississippi above Memphis.” Literature searches not only included reviews of papers and reports from well-known and established peer-reviewed scientific journals, but also “gray” literature sources such as unpublished technical reports, abstracts, and newspaper and popular magazine articles. As data were compiled, they were stored, sorted, and analyzed with Microsoft Excel and Access data base software. When latitude and longitude data were missing from a record and the locality data were sufficient, coordinates were assigned using one or more of the following aids: county road maps; Tennessee Atlas and GazetteerTM;Topozone.com website; Maptech.com Mapserver; Topo USATM software; GEOLocate software (courtesy of Tulane University); Yahoo.com maps service; and Google.com maps service. Distribution maps were generated with ArcGIS 9.2 software.
As of November 2019, our literature searches had yielded 4,298 Tennessee
reptile occurrence records in 700 documents. Surveys of institutional
collections had turned up 10,833 records, represented by 11,753 voucher specimens
and photographs dating back to 1855. The top five most-productive collections,
and numbers of records (in parentheses) obtained from each, include those at
Memphis State University (2,500), Austin Peay State University (1,966), Carnegie
Museum (1,377), University of Florida (865), and US National Museum (686). All
together, these contributed 7,390 records or 68% of the grand total from all 25
collections surveyed.
Key and Explanation of Map Symbols
Symbols used on the distribution maps are explained in the following key:
Key to Map Symbols
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Exact locality, based on specimen(s) or photographs examined |
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Exact locality, based on literature record believed valid |
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Approximate locality based on specimen(s) or photographs examined |
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Approximate locality based on literature record believed valid |
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County record only, based on specimens or photographs examined |
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County record only, based on literature report believed valid |
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Type locality |
? | Questionable and/or problematic record |
An exact locality (solid circle or solid square) is one based on data of sufficient detail and accuracy that the actual collection site falls within the bounds of the symbol provided on the distribution map. An approximate locality (open circle or open square) is one based on data lacking detailed information needed to pin point the site on a topographic map and therefore the actual collection site may not fall within the bounds of the map symbol. Based on available locality data, map symbols denoting approximate localities were placed near a topographic feature, such as the nearest town, park, game preserve, nature preserve, recreation area, or well-known camp. County records only (solid or open triangle) are those without locality data other than the county of origin. Type localities are denoted by an asterisk. A type locality is the place where the population from which a type specimen was taken occurs” (Mayer and Ashlock 1991), which may be exact or approximate. Localities marked by a question mark are considered questionable or problematic because the data are likely erroneous and/or there is reason to suspect a misidentification. Records of this nature are discussed in the appropriate species account. A map of Tennessee showing county names and boundaries is provided in Figure 1.
Plotting Rules and Protocols
A typical locality record from both museum and
literature sources is based on a specimen or specimens collected on a single
date from a single specific geographic locality. Plotting all records for a
species could result in cluttered and confusing distribution maps. Thus, certain
criteria and standard procedures were developed and used to not only determine
which records would be plotted, but how records would be plotted. The primary
goal of these protocols was to condense large and sometimes overlapping species
data sets, yet still provide adequate detail to allow the recognition of
distribution patterns and identification of counties and other geographic areas
where a species is currently not known to occur.
To avoid perpetuating possible errors in the
literature regarding the distribution of a particular species, we did not plot
locality records from a literature source where the author(s) used second-hand
sightings as the basis for the record. Many of these “hearsay” accounts are
discussed in the appropriate species account.
In order to avoid cluttered distribution maps, we
developed and used a computer protocol that allowed only one symbol to be
plotted for a specific geographic locality (either exact or approximate). This
avoided the confusion of many symbols being plotted one on top of another. Also,
we decided that locality records based on a specimen(s) from a museum source
took precedence over records for the same locality from a literature source.
For a given species, county records only (solid and
open triangles) were only plotted when no other exact or approximate locality
data (either museum or literature) were available for that county. Below are
three examples that illustrate the use of these protocols.
Example 1 – There are specimens of Trachemys scripta in several museum collections with different collection dates, but with a common collection site of Reelfoot Lake, Samburg. This site for T. scripta is also mentioned several times in the literature. In order to avoid clutter on the distribution map for T. scripta, only one symbol, a solid circle, appears on the distribution map.
Example 2 – A locality record for Sistrurus miliarius from the literature source Jacob (1981) was based on a specimen originally in the Memphis State University herpetology collection and now in the collection at Austin Peay State University. This locality is denoted on the distribution map for S. miliarius as a single map symbol, a solid circle.
Example 3 – Clark et. al (2003) provided what we believe to be valid information that Crotalus horridus was found in Williamson County. Because the authors provided no specific or approximate locality data, this record was classified as a county record only (open triangle). However, the record was not plotted on the final distribution map for C. horridus because other data were available for Williamson County. These data included an exact locality based on a specimen examined (solid circle), an approximate locality based on a specimen examined (open circle), and an approximate locality based on a literature record believed valid (open square).
Updates |
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Subsequent to the initial posting of species accounts and distribution maps, we will continue to search the literature for new state and county records. These new data will be used to periodically update the website.
If new records for a species are based on recently acquired voucher specimens or photographs in Austin Peay State University’s Museum of Zoology, they will be 1) plotted on the species' distribution map with an appropriate map symbol, 2) identified by their APSU catalog number in the account’s Specimens Examined by Counties section, and 3) cited in the account’s Literature Sources by Counties section. Also, the bibliographic information identifying the source of new records will be added to the website’s Literature Cited section.
If new records for a species are based on voucher specimens or photographs in collections other than APSU’s, no catalog number will be noted in the Specimens Examined by Counties section. However, these new records will be added to the species' distribution map with an appropriate map symbol and cited in the account’s Literature Sources by Counties section. The reference will be added to the website’s Literature Cited section.
Along with the changes mentioned above, each updated account will end with a statement following the original posting date that identifies the date of the latest revision.
Erroneous and Questionable Species Reports |
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An Ornate Box Turtle (Terrapene ornata) from
just east of Memphis was mentioned by Parker (1948) who suspected it might have
been released in the area by a traveler. The “Keeled Musk Turtle” (Sternotherus
carinatus) was included in Brimley’s (1926) “Revised key and list of the
amphibians and reptiles of North Carolina” as a species not yet known from North
Carolina but occurring in neighboring Tennessee. However, no references or
authorities were cited as the source for this information and no reports are
known for the species in Tennessee.
The Texas Horned Lizard (Phrynosoma cornutum)
was included by Gentry (1956) on his state reptile list, but was also clearly
identified as non-native species that sometimes ends up in the wild as released
or escaped pets. One specimen of P. cornutum from Graysville (Rhea
County) in the University of Illinois Museum of Natural History collection
(UIMNH 33960) also probably represents a release.
A single specimen of the Eastern Diamond-backed
Rattlesnake (Crotalus adamanteus) from near Bolivar was among the
reptiles listed from Hardeman County by Norton and Harvey (1975), but it was
considered to have been brought to the area from its native range. In 2007,
another specimen of this rattlesnake was found in Grundy County and housed for a
time at the Knoxville Zoo (Niemiller et al. 2013). It too was considered an
introduction from outside Tennessee. The Gopher Snake (Pituophis catenifer)
was reported by Gentry (1956) based on specimens from “the Tennessee River area”
that in some cases were intermediate between P. melanoleucus and P.
catenifer. However, since no subsequent reports or voucher specimens exists
to corroborate these assertions, P. catenifer is not considered part of
the state’s reptile fauna. Known at the time as Liopeltis vernalis, the
Smooth Greensnake (Opheodrys vernalis) was reported by Endsley (1954) as
“not abundant” but yet “not uncommon” in western Tennessee. More specifically,
he references “a preserved specimen collected near Henderson, Tennessee, May 15,
1934.” However, the specimen could not be located and the occurrence of this
species in the state is considered doubtful. Lastly, among the records
considered questionable is the Lined Snake (Tropidoclonion lineatum).
Represented by a specimen in the US National Museum (USNM 56030) with “Sherwood,
Franklin County, Tennessee” as the collection locality, this record may likely
be the result of corrupted locality data because the closest records to the
Franklin County locality are approximately 530 km away in Jefferson County,
Missouri (Johnson 1987). Ramsey (1953, p. 7) also had doubts about the validity
of this record as expressed in the following quote:
The locality given for U.
S. Nat. Mus. No. 56030 as Sherwood, Franklin County, Tennessee is . . . regarded
with doubt. It is remote from any other records for the species. Dr. Doris M.
Cochran has informed me that this specimen, along with some 5000 other
specimens, was given to the United States National Museum by the estate of
Julius Hurter, but that Hurter’s original catalogues and correspondence were
never made available to the museum. There is thus no way by which to check upon
the source of this specimen.
Species of Possible Occurrence |
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Three species (one turtle and two snakes) occur close enough to the state’s boundary to be considered as possible residents. The Alabama Map Turtle (Graptemys pulchra) is know from five localities along the Conasauga River drainage in Whitfield and Murray counties, Georgia (John Jensen, personal communication). The northernmost of these sites is within 14 river kilometers of the portion of the Conasauga that flows through Bradley County, Tennessee. The Chicken Turtle (Deirochelys reticularia) has been recorded in New Madrid County, Missouri (Daniel et al. 2014) and Mississippi County, Arkansas (Niemiller et al. 2013), both just across the Mississippi River from Tennessee. Records of Graham’s Crayfish Snake (Regina grahamii) also exist from Mississippi County, Arkansas (Trauth et al. 2004) and from Dunklin (Daniel et al. 2014, verified) and New Madrid (Johnson 2000, unverified) counties Missouri, also a short distance across the Mississippi River from Tennessee.
Numbers of Species Per County |
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As
of January 2019, the numbers of species known from each county based on both
museum specimens and literature reports ranged from a low of four in Sequatchie
County to a high of 46 in Shelby County (Fig. 2). One noticeable geographical trend among the total
data set is that counties with the highest reptilian species diversity are 1)
counties with colleges or universities that have a history of research and
instruction in herpetology and/or 2) counties that possess or are close to
accessible tracts of public lands. Of the eight counties with the highest number
of documented species, all fall into one or both of these categories. Shelby
County (46 species) has the University of Memphis (formally Memphis State
University), T. O. Fuller State Park, and Meeman-Shelby Forest State Park.
Hardeman County (45 species) is just one county removed from Shelby and is well
represented by reptile records in the literature and among specimens in the
former Memphis State University herpetology collection (now housed at Austin
Peay State University). Stewart County (44 species) includes Stewart State
Forest, Cross Creeks National Wildlife Refuge, and the southern half of Land
Between The Lakes, plus it is within easy driving distance to Austin Peay State
University and Murray State University. Obion County (40 species) includes
portions of Reelfoot National Wildlife Refuge, Reelfoot Lake State Park,
Reelfoot State Wildlife Management Area, and is near the University of Tennessee
at Martin. Montgomery County (39 species) has Austin Peay State University,
Dunbar Cave State Park and Natural Area, Shelton Ferry Wetland, Haynes Bottom
Wildlife Management Area, and near-by Land Between The Lakes. Blount County (39
species) is within easy reach of the University of Tennessee at Knoxville, and
include portions of Great Smoky Mountains National Park and Cherokee National
Forest. And finally, Franklin (39 species) and Hamilton (40 species) counties
together include The University of the South and The University of Tennessee at
Chattanooga, plus parts of Franklin-Marion State Forest and Arnold Air Force
Base, Harrison Bay State Park, and the area formerly occupied by the Volunteer
Army Ammunition Plant.
Posted: 1 May 2008
Latest Update: 18 November 2019
Atlas of Reptiles in Tennessee - Title/Contents Page
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This document is being adapted to the WWW by Jean Langley, Floyd Scott, and Rusty Smith.