Data acquisition for the Atlas of Reptiles in Tennessee (http://www.apsu.edu/reptatlas) began in 1998 and continued intermittently through August, 2007. The aim was to produce a companion document to the Atlas of Amphibians in Tennessee (Redmond and Scott 1996), now available in hard copy from the Center for Field Biology, Austin Peay State University, Clarksville, Tennessee, and on the Internet (at http://www.apsu.edu/amatlas/index.html). The Internet version 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. To hasten the dissemination of reptile distribution data, the decision was made to launch a new web site with introductory and background information plus species accounts for the family Viperidae. Additional species accounts will be added periodically to the web site until all species known to occur in the state have been covered. The 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.

This project was guided by the following specific objectives:

We hope the information contained in this document 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 spur readers, both professional and amateur, to fill these gaps by documenting and publishing new county records.

Nomenclature above the level of species follows that of Conant and Collins (1998).  With a few exceptions, the scientific and common names provided in individual species accounts are those provided by Crother (2008).  In individual species accounts the appropriate subsection of Crother (2008) is cited as the source.

Baseline Distribution Data

As stated above, baseline distribution data were taken from two main sources: museum collections and literature sources.   From 1998 - 2007 we examined specimens from 25 institutions scattered throughout eastern United States (Table 1). Our review of the herpetological literature extended back to1835, when the earliest published Tennessee reptile record appeared (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 amassed, they were stored, sorted, and analyzed with Microsoft Excel and Access data base software. A master data base of all records was created along with ones for each museum collection and each species. 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 Gazetteer^TM;Topozone.com website; Maptech.com Mapserver, Topo USA^TM 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.

The literature search identified 419 documents that included 2859 references to reptile occurrences in Tennessee. The distribution of these occurrence reports by decade from the 1830s into the 2000s is provided in Figure 1.

Trips to institutional collections yielded 9827 records, representing 10,738 specimens collected from the 1850s to the 2000s (Fig. 2). The top five most-productive collections, and numbers of records (in parentheses) obtained from each, were those at Memphis State University (2086), Austin Peay State University (1431), Carnegie Museum (1377), University of Florida (865), and US National Museum (686). All together, these contributed 6445 records or 66% of the grand total from all 25 collections surveyed.

Reports of 66 species of extant reptiles in Tennessee were obtained from the literature; 58 species (all mentioned in the literature reports) were represented among the museum specimens examined. Of the 66 species reported, only 58 species (from four families of turtles, five families of lizards, and five families of snakes) are considered native to the state. The other eight, discussed below in a separate section, are likely based on encounters with escaped (or released) exotics, misidentified specimens, or corrupted locality data.

Key and Explanation of Map Symbols

Symbols used on the distribution maps are explained in the following key:

Key to Map Symbols
	Exact locality, based on specimen(s) or photographs examined
	Exact locality, based on literature record believed valid
	Approximate locality based on specimen(s) or photographs examined
	Approximate locality based on literature record believed valid
	County record only, based on specimens or photographs examined
	County record only, based on literature report believed valid
	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 we feel the actual collection site falls within the bounds of the symbol on the distribution map.   An approximate locality (open circle or open square) is one based on data lacking detailed information necessary to pin point the site on a topographic map and therefore the actual collection site may not fall withinthe bounds of the map symbol. In general, map symbols denoting approximate localities fall relatively close to where the animal was found, such as the nearest town or in a public or private parcel of land of limited size with a recognized name such as a 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 locality (an asterisk) “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 account for the species they purportedly represent. A map of Tennessee showing county names and boundaries is provided in Figure 3.

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 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, will appear on the 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).

 

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.

The American Alligator (Alligator mississipiensis) and Texas Horned Lizard (Phrynosoma cornutum) were included by Gentry (1956) in his state reptile list, but were also clearly identified as non-native species that sometimes end 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. 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 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. The “Keeled Musk Turtle” (Sternotherus carinatus) was included as a species occurring in the neighboring state of Tennessee (“West Tennessee” to quote him) in Brimley’s (1926) “Revised key and list of the amphibians and reptiles of North Carolina.” But no references or authorities were cited as sources for this information and no reports of the species in the state exist before or since.   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.

Two historical trends in the data seem apparent. First, literature records, which have oscillated from decade to decade over the past seventy years, are projected to increase dramatically by the end of current decade as interest in filling gaps in known distributions increases. Second, museum records which peaked in the 1970s have declined and are not expected to increase to any significant degree in the coming years due to increased restrictions and controls over collecting and a gradual shift in philosophy toward non-consumptive research techniques (e.g. non-lethal tissue samples and photography).

The numbers of species known from each county based on both museum specimens and literature reports ranged from a low of 0 in Marshall and Macon counties to a high of 45 in Hardeman County (Fig. 4). One noticeable geographical trend among the total data set is that the number of reptilian species per county is highest in or near counties with 1) colleges or universities that have a history of research and instruction in herpetology and/or 2) those with or close to accessible tracts of public lands. Of the 10 counties with the highest number of documented species, all fall into this category. Shelby County (42 species) has the University of Memphis (formally Memphis State University) and T. O. Fuller and Meeman-Shelby Forest state parks. Hardeman County (43 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. Stewart County (42 species) includes Stewart State Forest, Cross Creeks National Wildlife Refuge, and the southern half of Land Between The Lakes with nearby Austin Peay State University and Murray State University. Lake and Obion counties (31 and 37 species, respectively) include portions of Reelfoot National Wildlife Refuge, Reelfoot Lake State Park, Reelfoot State Wildlife Management Area, and the nearby campus of the University of Tennessee at Martin. Montgomery County (37 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. Putnam County has Tennessee Technological University. Polk and Monroe counties include portions of the Cherokee National Forest. Blount and Sevier counties have Great Smoky Mountains National Park, and nearby Knox County is where the University of Tennessee is located.

Posted: 1 May 2008

Updated: 19 November 2008

Atlas of Reptiles in Tennessee - Title/Contents Page  

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