A Natural History of Conewago Falls—The Waters of Three Mile Island
Reptiles
REPTILES
of the Lower Susquehanna River Watershed
With (forthcoming) commentary on the species including notes from the historic writings of nineteenth-century geologist, naturalist, and philologist Professor Samuel Steman Haldeman and Linnaean Society of Lancaster City and County naturalist Jacob Stauffer.
Samuel Steman Haldeman was born in 1812 at the Haldeman Mansion along the Susquehanna River at Locust Grove near Bainbridge in Lancaster County, Pennsylvania. The mansion can be seen from the Northwest Lancaster County River Trail and is open for tours during scheduled events. See the Haldeman Mansion Preservation Society website for more information.In the vicinity of his boyhood home at the mouth of Conoy Creek, Haldeman explored the waters and shores of the Susquehanna below Conewago Falls. He developed an interest in the animal bones he found and began assembling skeletons. Haldeman collected the shells of the mollusks occurring there, a long-term pursuit that eventually led to the writing and publishing of “A Monograph of the Freshwater Univalve Mollusks of the United States” and “On the Freshwater Mollusca Common to Europe and America, Including Theoretical Observations Upon the Species and Their Distribution”. The former was the country’s first comprehensive account of its freshwater snails. Charles Darwin would comment on the latter in “The Origin of Species” as part of the book’s appendix, “…An Historical Sketch of the Progress of Opinion on the Origin of Species”.During his adult years, Samuel Steman Haldeman resided along the Susquehanna at Chickies Rock near Marietta, Pennsylvania. He died at his home there in 1880. Haldeman left behind a wide-ranging body of work in the fields of geology, zoology, linguistics, and archaeology. Among these are commentary on the animals, including the reptiles, found in Lancaster County during the early 1800s. His use of binomial nomenclature relieves us of the uncertainty that comes with interpreting similar lists of wildlife that use colloquial names. His sketch is the foundation of this list. (Mathew Brady image-Library of Congress)
SPECIES STATUS KEY
extinct-a native species no longer existing or living.
extirpated-a native species no longer occurring in the wild in the Lower Susquehanna River Watershed.
exotic-a free-ranging escaped or released non-native species or variety; most are unwanted pets, domesticated farm animals, or zoo specimens.
introduced-a non-native species that, following its release into the wild, has established a self-sustaining breeding population—often at the expense of one or more native species.
Federally Endangered-a native species listed by the United States government as imminently in danger of extinction.
PA Endangered-a native species listed by the Commonwealth of Pennsylvania as imminently in danger of extinction or of extirpation as a breeding species in the state.
MD Endangered-a native species listed by the State of Maryland as imminently in danger of extinction or of extirpation as a breeding species in the state.
Federally Threatened-a native species listed by the United States government as under threat to become an endangered species in the foreseeable future.
PA Threatened-a native species listed by the Commonwealth of Pennsylvania as under threat to become an endangered species in the state in the foreseeable future.
MD Threatened-a native species listed by the State of Maryland as under threat to become an endangered species in the state in the foreseeable future.
PA Candidate-an uncommon native species that could, in the future, become listed by the Commonwealth of Pennsylvania as endangered or threatened in the state.
A LIST OF THE REPTILES
of the Lower Susquehanna River Watershed
Classified using traditional taxonomic ranks and selected cladistic groups.
Domain-Eukaryota
Kingdom-Animalia
Phylum-Chordata
Subphylum-Vertebrata
Superclass-Osteichthyes/Clade-Euteleostomi:
The “bony vertebrates” including the Actinopterygians, the ray-finned fishes, and the Sarcopterygians, the lobe-finned fishes and tetrapods.
Clade-Sarcopterygii:
The lobe-finned fishes and tetrapods. All members of the clade Sarcopterygii presently occurring in the Susquehanna watershed (amphibians, reptiles, birds, and mammals including humans) are tetrapod descendants of extinct lobe-finned fishes.
Superclass-Tetrapoda:
The animals descended from fishes beginning in the Late Devonian epoch (about 370 million years ago), most having four limbs—the amphibians, the reptiles (including snakes, pterosaurs, dinosaurs, and birds), and the mammals.
Clade-Reptiliomorpha:
The group of living and extinct tetrapods having more similarity to the amniotes (reptiles, pterosaurs, dinosaurs, birds, and mammals) than to modern amphibians (Lissamphibia).
Clade-Amniota:
The group of tetrapods, living and extinct, that deposit their eggs on land (not in water) or retain them within the body—the reptiles (including pterosaurs, dinosaurs, and birds) and the mammals.
The female Wood Turtle (Glyptemys insculpta) deposits her eggs on land in a nest she has excavated with her hind feet. After closing the burrow, she departs. Heat from the sun-warmed soil will incubate the eggs. Upon hatching, the newborn turtles fend for themselves.Newborn Eastern Copperheads (Agkistrodon contortix) gather outside a birthing den. Their mother retained her eggs inside her body. The embryos complete development there, then are born as self-sufficient young copperheads. The pale yellowish tip of their tail is used to lure small insects and other prey into striking range.
Clade-Sauropsida:
The group of all living and extinct reptiles (including birds and the extinct Parareptilia).
Clade-Diapsida
The group of living and extinct sauropsid amniotes with two openings—temporal fenestra—behind each eye orbit.
Two temporal fenestra openings are noted on the skull of the Meleagris gallopovo, the Wild Turkey. Some diapsids have lost temporal fenestra openings over time; snakes have none and modern lizards have only one behind each eye. (Smithsonian National Museum of Natural History image www.si.edu)
Class-Reptilia:
The non-avian and avian reptiles.
For images and descriptions of the avian reptiles—the members of the traditional taxonomic class Aves—click the “Birds” tab at the top of this page.
Spotted Turtle (Clemmys guttata).A female Wood Turtle (Glyptemys insculpta).The tiny Bog Turtle (Glyptemys muhlenbergii) is federally listed as a threatened species. It has the same status in Maryland. Under Pennsylvania law, the Bog Turtle is an endangered species. (United States Fish and Wildlife Service image) Eastern Box Turtle (Terrapene carolina).Yellow-bellied Slider (Trachemys scripta scripta). (Vintage 35 mm image)Unwanted pet Red-eared Sliders (Trachemys scripta elegans), natives of the Mississippi drainage, have been released into numerous bodies of water in the lower Susquehanna valley. Numbers of these reptiles are increasing at the expense of the rarer Emydid species whose critical habitats they are invading.An adult female Red-eared Slider (Trachemys scripta elegans) at Conewago Falls.The ranges of two subspecies of Painted Turtle (Chrysemys picta), the Eastern Painted Turtle (C. p. picta) and the Midland Painted Turtle (C. p. marginata), overlap in the Lower Susquehanna River Watershed. Within the intergrade zone, individuals typical of the eastern subspecies with scutes in a straight row across the carapace (top shell) may also show the dark shadow patterns on the yellow plastron (bottom shell) below, a trait typical of the midland subspecies. Painted Turtles (Chrysemys picta) in the Susquehanna valley with misaligned scutes across the carapace most resemble Midland Painted Turtles (C. p. marginata), but may, like the Eastern Painted Turtle (C. p. picta), lack shadowy patterns on the yellow plastron below.A Painted Turtle (Chrysemys picta) atop a Snapping Turtle (Chelydra serpentina).Painted Turtles (Chrysemys picta) with a much larger adult Red-eared Slider (Trachemys scripta elegans), a non-native species.A juvenile Painted Turtle (Chrysemys picta).Northern Map Turtle (Graptemys geographica).A Northern Map Turtle (Graptemys geographica) and a noticeably larger adult Red-eared Slider (Trachemys scripta elegans), the latter a non-native species.Diamond-backed Terrapin (Malaclemys terrapin). (United States Fish and Wildlife Service image by Ryan Hagerty)A Northern Red-bellied Cooter (Pseudemys rubriventris) and a much smaller Painted Turtle.
Family-Trionychidae
Apalone spinifera (Spiny Softshell)-exotic
Spiny Softshell (Apalone spinifera). (United States Department of Energy Fermi National Accelerator Laboratory image by Leticia Shaddix)
North American Racer (Coluber constrictor). (Vintage 35 mm image)The Eastern Ratsnake (Pantherophis alleghaniensis). The Eastern Ratsnake (Pantherophis alleghaniensis).A juvenile Eastern Ratsnake (Pantherophis alleghaniensis).The California Kingsnake (Lampropeltis californiae), a native of the North American West Coast, is commonly kept and bred as a pet. During late April of 2022, an escaped or released specimen was found living in a barn in Manheim, Lancaster County, Pennsylvania. (Connor Long image)Eastern Milksnake (Lampropeltis triangulum). (United States Fish and Wildlife Service image by Jeff Servoss)In the lower Susquehanna valley, the Rough Greensnake (Opheodrys aestivus) is found only near the Mason-Dixon Line, at the northern limit of its range. It sparsely populates riparian forests in the vicinity. Because of its limited distribution, it is listed as endangered in Pennsylvania. (United States Fish and Wildlife Service image by Mike Boylan)Smooth Greensnake (Opheodrys vernalis). (National Park Service image)Northern Watersnake (Nerodia sipedon sipedon).Northern Watersnake (Nerodia sipedon sipedon).A juvenile Northern Water Snake (Nerodia sipedon sipedon).A juvenile Northern Water Snake (Nerodia sipedon sipedon).Dekay’s Brown Snake (Storeria dekayi). (Grace Fox Good image)Northern Red-bellied Snake (Storeria occipitomaculata occipitomaculata). (Image by Digby Dalton, under license: CC BY-SA 3.0)Eastern Ribbonsnake (Thamnophis sauritus sauritus). (United States Fish and Wildlife Service image by Jim Hudgins)Eastern Gartersnake (Thamnophis sirtalis sirtalis). (Luke Fox image)Smooth Earthsnake (Virginia valeriae). (Image by Don F. Becker, under license: CC BY-SA 4.0)Eastern Wormsnake (Carphophis amoenus amoenus). (Image by Greg Schechter, under license: CC BY 2.0)Northern Ring-necked Snake (Diadophis punctatus edwardsii).A Northern Ring-necked Snake (Diadophis punctatus edwardsii) beginning the process of shedding its skin.Northern Ring-necked Snake (Diadophis punctatus edwardsii).Eastern Hog-nosed Snake (Heterodon platirhinos). (Fred Wilcox image)Eastern Hog-nosed Snake (Heterodon platirhinos) feigning death. (Fred Wilcox image)
Family-Pythonidae
Python regius (Ball Python)-exotic
Python reticulatus (Reticulated Python)-exotic
The Ball Python (Python regius), a native of central Africa, occurs on occasion as a released or escaped pet in the lower Susquehanna valley. One was found in September, 2018, among the gasoline pumps at a convenience store in New Holland, Lancaster County, Pennsylvania. (Public Domain image)The Reticulated Python (Python reticulatus), a native of southern Asia, sometimes occurs as a released or escaped pet in the lower Susquehanna region. A wandering specimen engorged by a recent meal was captured in Lancaster County, Pennsylvania, in the first days of October, 2019. Reticulated Pythons are the lengthiest snakes on earth, some measuring 20 feet or more. The larger ones have been known to constrict and kill humans. Outdoors, pythons exposed to the climate of the Mid-Atlantic States in autumn soon perish. (Public Domain image)
Family-Viperidae
Agkistrodon contortix (Eastern Copperhead)
Crotalus horridus (Timber Rattlesnake)
An adult Eastern Copperhead (Agkistrodon contortix). (Fred Wilcox image)Adult Eastern Copperheads (Agkistrodon contortix) outside a birthing den.Closeup of an adult Eastern Copperhead (Agkistrodon contortix) outside its birthing den.An adult Eastern Copperhead (Agkistrodon contortix) outside its birthing den.A juvenile Eastern Copperhead (Agkistrodon contortix) outside a birthing den.A juvenile Eastern Copperhead (Agkistrodon contortix) displaying the yellow tip of its tail, a lure used to attract potential prey including small insects.A female yellow-phase Timber Rattlesnake (Crotalus horridus) at its birthing den.Close-up view of a Timber Rattlesnake (Crotalus horridus) showing the facial pit in front of the eye and the vertical pupil, traits typical of pit vipers (Viperidae).Timber Rattlesnakes (Crotalus horridus), an adult female with juveniles, outside a birthing den on September 1, 2011. (Fred Wilcox image)Juvenile Eastern Copperheads (Agkistrodon contortix) outside the same birthing den on September 24, 2011.
Clade-Archosauria:
The group of living and extinct diapsid sauropsids that is comprised of phytosaurs, crocodilians, pterosaurs, dinosaurs, and birds—all descended from a shared Early Triassic ancestor.
Clade-Pseudosuchia:
The group of archosaurs more closely related to crocodilians than birds. Includes Galtonia gibbidens, an extinct Late Triassic pseudosuchian known only from bones and teeth recovered from strata in the Gettysburg Basin’s New Oxford Formation at the bottom of a shaft at the Le Crone copper prospect near Manchester, York County, Pennsylvania. The species was discovered there by Atreus Wanner, then described by Edward Cope as Thecodontosaurus gibbidens in 1878. It lived more than 220 million years ago.
Order-Phytosauria
Family-Phytosauridae
Rutiodon carolinensis–extinct
Redondosaurus species (“Giant Phytosaur”)-extinct
More than 220 million years ago, the Triassic phytosaur Rutiodon carolinensis was a resident in the swamps of the Gettysburg Basin in what is today the lower Susquehanna valley. Unlike alligators and crocodiles, a phytosaur’s nostrils were just in front of its eyes, not toward the anterior end of a long snout. Its rear legs were proportionally longer than those of crocodilians. (Life-sized model: State Museum of Pennsylvania, Harrisburg)Fossilized remains of Rutiodon carolinensis have been found in New Oxford Formation sediments in York County, Pennsylvania. (Life-sized model: State Museum of Pennsylvania, Harrisburg)A “Giant Phytosaur” (Redondosaurus species) is depicted guarding its nest in a Triassic Period diorama featuring a man-made skeleton of a very large adult. This reconstruction is based upon a fossil tooth specimen found in New Oxford Formation sediments in York County, Pennsylvania. (Life-sized model: State Museum of Pennsylvania, Harrisburg)
Order-Crocodylia
Family-Crocodylidae
Caiman crocodilus (Spectacled Caiman)-exotic
Crocodilians and other reptiles outgrow their desirability as pets and are often released into the wild by irresponsible owners. The Spectacled Caiman (Caiman crocodilus), a native of tropical Central and South America, has been found at least once in the Lower Susquehanna River Watershed. During a summer in the late 2000s, a single individual was reported lurking in Kreutz Creek in York County, Pennsylvania. Following the onset of cool autumn weather, it was not seen again. (Smithsonian National Museum of Natural History image by Steven Paton, Smithsonian Tropical Research Institute, www.si.edu)
The American Alligator (Alligator mississippiensis) has been found free-roaming the lower Susquehanna’s waterways on a number of occasions. One of the most recent records was in 2007 in the vicinity of Doubling Gap Creek, a tributary of the Conodoguinet Creek in Cumberland County, PA. Crocodilians released into Atlantic Slope waters north of the Carolinas cease feeding as temperatures cool in autumn; by winter, they’re dead.
Clade-Avemetatarsalia:
The group of archosaurs most resembling birds (includes pterosaurs and dinosaurs).
For images and descriptions of the dinosaur life once found in the Lower Susquehanna River Watershed, click the “Geology, Fossils, and More” tab at the top of this page.
For images and descriptions of the birds—the traditional taxonomic class Aves—click the “Birds” tab at the top of this page.
SOURCES
Crother, Brian I. (Chair) Committee On Standard English And Scientific Names. 2017. “Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico, with Comments Regarding Confidence in Our Understanding”. Eighth Edition. Society for the Study of Amphibians and Reptiles Herpetological Circular No. 43. Shoreview, MN. pp. 1-102.
Haldeman, Samuel Steman. 1844. “Natural History of Lancaster County: Reptilia—Reptiles”. I. Daniel Rupp’s History of Lancaster County. Gilbert Hills. Lancaster, PA. pp.471-472.
Maryland Natural Heritage Program. 2016. List of Rare, Threatened, and Endangered Animals of Maryland. Maryland Department of Natural Resources, 58 Taylor Avenue, Annapolis, MD 21401.
Pennsylvania Natural Heritage Program. PNHP Species Lists. www.naturalheritage.state.pa.us/Species.aspx Accessed August 14, 2019.
Shaffer, Larry L. 1991. Pennsylvania Amphibians and Reptiles. Pennsylvania Fish and Boat Commission. Harrisburg, PA.
Species Accounts—Pennsylvania Amphibian and Reptile Survey. Website: https://paherpsurvey.org/species.php Accessed 29 July, 2019.
Stauffer, Jacob. 1869. “Herpetology: Class of Reptiles”. J. I. Mombert’s An Authentic History of Lancaster County. J. E. Barr and Company. Lancaster, PA. pp.574-576.
Stose, George W. and Jonas, Anna I. 1939. Geology and Mineral Resources of York County, Pennsylvania. Pennsylvania Geological Survey. Fourth Series. Bulletin C 67.
United States Geological Survey Nonindigenous Aquatic Species Database. http://nas.er.usgs.gov Accessed August 18, 2019.
