Volume 6, 2024 No. 11 The Zeta Pond Site: A New Rancholabrean Local Fauna from Pinellas County, Florida Jakob H. Pammer, Peter A. Meylan, and Richard C. Hulbert Eastern Paleontologist EASTERN PALEONTOLOGIST The Eastern Paleontologist (ISSN # 2475-5117) is published by the Eagle Hill Institute, PO Box 9, 59 Eagle Hill Road, Steuben, ME 04680-0009. Phone 207-546-2821 Ext. 4, FAX 207-546-3042. E-mail: office@eaglehill.us. Webpage: http://www.eaglehill. us/epal. Copyright © 2021, all rights reserved. Published on an article by article basis. Special issue proposals are welcome. The Eastern Paleontologist is an open access journal. Authors: Submission guidelines are available at http://www.eaglehill.us/epal. Co-published journals: The Northeastern Naturalist, Southeastern Naturalist, Caribbean Naturalist, and Urban Naturalist, each with a separate Board of Editors. The Eagle Hill Institute is a tax exempt 501(c)(3) nonprofit corporation of the State of Maine (Federal ID # 010379899). Board of Editors Lisa Amati, New York State Museum, Albany, NY Richard Bailey, Northeastern University, Boston, MA David Bohaska, Smithsonian Institution, Washington, DC Michael E. Burns, Jacksonville State University, Jacksonville, AL Laura Cotton, Florida Museum of Natural History, Gainesville, FL Dana J. Ehret, New Jersey State Museum, Trenton, NJ • Co- Editor Robert Feranec, New York State Museum, Albany, NY Steven E. Fields, Culture and Heritage Museums, Rock Hill, SC Timothy J. Gaudin, University of Tennessee, Chattanooga, TN Russell Graham, College of Earth and Mineral Sciences, University Park, PA Alex Hastings, Virginia Museum of Natural History, Martinsville, VA Andrew B. Heckert, Appalachian State University, Boone, NC Melanie Jane Hopkins, American Museum of Natural History, New York, NY Richard Hulbert, Florida Museum of Natural History, Gainesville, FL Steven Jasinski, State Museum of Pennsylvania, Harrisburg, PA Chris N. Jass, Royal Alberta Museum, Edmonton, AB, Canada Michal Kowalewski, Florida Museum of Natural History, Gainesville, FL Joerg-Henner Lotze, Eagle Hill Institute, Steuben, ME • Publisher Jim I. Mead, The Mammoth Site, Hot Springs, SD James Mickle, North Carolina State University, Raleigh, NC • Co-Editor Roger Portell, Florida Museum of Natural History, Gainesville, FL Frederick S. Rogers, Franklin Pierce University, Rindge, NH • Co-Editor Joshua X. Samuels, Eastern Tennessee State University, Johnson City, TN Blaine Schubert, East Tennessee State University, Johnson City, TN Gary Stringer (Emeritus), University of Louisiana, Monroe, LA Chase Uy, Eagle Hill Institute, Steuben, ME • Production Editor Steven C. Wallace, East Tennessee State University, Johnson City, TN ♦ The Eastern Paleontologist is a peer-reviewed journal that publishes articles focusing on the paleontology of eastern North America (ISSN 2475-5117 [online]). Manuscripts based on studies outside of this region that provide information on aspects of paleontology within this region may be considered at the Editor’s discretion. ♦ Manuscript subject matter - The journal w elcomes manuscripts based on paleontological discoveries of terrestrial, freshwater, and marine organisms and their communities. Manuscript subjects may include paleo - zoology, paleobotany, micropaleontology, systematics/ taxonomy and specimen-based research, paleoecology (including trace fossils), paleoenvironments, paleobio - geography, and paleoclimate. ♦ It offers article-by-article online publication for prompt distribution to a global audience. ♦ It offers authors the option of publishing lar ge files such as data tables, and audio and video clips as online supplemental files. ♦ Special issues - The Eastern Paleontologist welcomes proposals for special issues that are based on conference proceedings or on a series of invitational articles. Special issue editors can rely on the publis her’s years of experiences in efficiently handling most details relating to the publication of special issues. ♦ Indexing - The Eastern Paleontologist is a young journal whose indexing at this time is by way of author entries in Google Scholar and Researchgate. Its indexing coverage is expected to become comparable to that of the Institute's first 3 journals (Northeastern Naturalist, Southeastern Naturalist, and Journal of the North Atlantic). These 3 journals are included in full -text in BioOne.org and JSTOR.org and are indexed in Web of Science (clarivate.com) and EBSCO.com. ♦ The journal's staff is pleased to discuss ideas for manuscripts and to assist during all stages of manu - script preparation. The journal has a page char ge to help defray a portion of the costs of publishing manu - scripts. Instructions for Authors are available online on the journal’s website (http://www.eaglehill.us/epal). ♦ It is co-published with the Northeastern Naturalist, Southeastern Naturalist, Caribbean Naturalist, Urban Naturalist, Eastern Biologist, and Journal of the North Atlantic. ♦ It is available online in full-text version on the journal's website (http://www.eaglehill.us/epal). Arrangements for inclusion in other databases are being pur - sued. Cover Photograph: Top Left: Dorsal view of the trunk vertebrae of Siren lacertina (top), UF 247330 and Amphiuma means (bottom), UF 247316. Top Right: Equus sp., right p2 in occlusal view (UF 247516). Bottom: The medial view of a right dentary from Anolis carolinensis (UF 247400). Photographs © Jakob Pammer. Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 1 2024 EASTERN PALEONTOLOGIST 11:1–18 The Zeta Pond Site: A New Rancholabrean Local Fauna from Pinellas County, Florida Jakob H. Pammer¹*, Peter A. Meylan1,and Richard C. Hulbert2 Abstract – A rich Rancholabrean local fauna representing a freshwater marsh community with adjacent uplands is identified from a site in St. Petersburg, Florida. During the winter of 2008, sediments excavated on the Eckerd College campus produced a previously unknown assemblage of fossil terrestrial and aquatic vertebrates. All fossils found to date can be assigned to a Late Pleistocene age. Remains of Holmesina septentrionalis, Sigmodon hispidus and Amphiuma means provide evidence that the age of the site falls within the Rancholabrean North American Land Mammal Age. The fossils consist of many aquatic vertebrates with alligators, freshwater turtles, amphibians, and aquatic snakes being the more common elements found. These suggest deposition in or near a large source of freshwater, most likely a marsh. Fragmentary fossils of terrestrial mammals including large herbivores such as horse, tapir, and mammoth were most likely washed into the site from adjacent upland habitats. Introduction During the winter of 2008, two adjacent retention ponds on the south side of the Eckerd College campus (27°42’55.4”N 82°41’28.5”W) were merged together and deepened to meet the needs of the growing campus. The excavated sediments were moved to another site on campus for future construction projects. Occasional fossils have been found on the Eckerd College campus, but preliminary investigation of the pond sediments indicated that a fauna including many different species was present and of scientific importance. The name given to this new fossil locality is the Zeta Pond Site (Fig. 1). 1Eckerd College, St. Petersburg, FL 33711. 2Division of Vertebrate Paleontology, Florida Museum of Natural History, Gainesville, FL 32611. *Corresponding author: jakob.pammer07@gmail.com Associate Editor: Dana Ehret, New Jersey State Museum. Figure 1. Map of the Zeta Pond site in relation to Seminole Field and Leisey Shell Pit 1A fossil localities (Courtesy of Google Earth). Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 2 The Zeta Pond Site has produced over 400 fossil specimens and provides data on Westcentral Florida at the end of the Pleistocene. The site has produced many modern taxa including Amphiuma, Sigmodon, Procyon, and Didelphis. Other fauna found at the Zeta Pond Site include many taxa that were present during the late Pleistocene, but are now extinct in Florida including Hesperotestudo, Equus, Tapirus, Neochoerus, and Palaeolama. This new fauna can be evaluated within the rich framework of previously studied sites in West-central Florida including the comparable late Pleistocene fauna from Seminole Field, and the older but very well-studied fauna of Leisey Shell Pit (Hillsborough County; Morgan and Hulbert 1995) which provides a rich record for the early Irvingtonian. Although Zeta Pond is rich in fossil material, transportation of the sediment during construction damaged many of the specimens collected indicated by breaks in the fossils that lacked patina or signs of weathering. Despite this, the site has yielded a large number of identifiable specimens which currently includes at least 3 species of amphibians, 16 reptiles, 5 birds, and 21 mammals (see Supplemental Table 1, available online at eaglehill.us/epalonline/supplfiles/ epal-012-pammer-s1.pdf). Fossil material has been identified as completely as possible with help from David Steadman (birds), and Jason Bourque (turtles). This report documents the Rancholabrean vertebrate fauna on what is now Eckerd College and reconstructs the environment in which that fauna lived. Materials and Methods Collection of the Zeta Pond Site began in January 2008 and produced specimens until 2010. None have been associated or articulated due to relocation of the sediment during construction; all consist of disarticulated surface finds. Most collections were made after heavy rains eroded material out of the spoil mound. The sediment containing the fossils consists of loose sand and shell material. Some screening of sediment was done using quarter inch and sixteenth inch sized mesh, but this yielded very few fossils, so was abandoned in favor of surface prospecting. Preliminary identification of the fossils was done at Eckerd College using recent skeletal specimens for comparison. Once specimens were identified they were photographed using an SLR Lumix DMC-FZ28 camera. Extremely small fossils were photographed with a camera mounted on a microscope. After the faunal list was generated, the habitat requirements for each species were derived from the literature and the paleoecology of the site reconstructed. All specimens have been cataloged into the Florida Museum of Natural History collections, Gainesville (UF). Results Systematic paleontology CAUDATA Scopoli, 1777 SIRENIDAE Linnaeus, 1766 Siren lacertina Linnaeus, 1766 Referred Specimens: 14 trunk vertebrae, UF 247316–247329. Description: Vertebrae of the Family Sirenidae are amphicoelus and can be quite large. When viewed dorsally there is a pronounced posteromedial notch (Fig. 2). Trunk vertebrae of the Zeta Pond siren are most morphologically similar to that of the Greater Siren (S. lacertina). Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 3 Figure 2. Dorsal view of the trunk vertebrae of Siren lacertina (top), UF 247330 and Amphiuma means (bottom), UF 247316. (Photos by Jakob Pammer). Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 4 AMPHIUMIDAE Garden, 1821 Amphiuma means Garden, 1821 Referred Specimens: 20 trunk vertebrae, UF 247330–247349; 1 atlas vertebrae, UF 247350. Description: Amphiuma also have large amphicoelous vertebrae. They differ from Sirenidae, however, in that they lack the pronounced posteromedial notch at the posterior end. The neural crest extends past the centrum between the postzygopophysis. ANURA Merrem, 1820 RANIDAE Rafinesque, 1814 Lithobates sp. indet Referred Specimens: 5 humeri, UF 247351–247355; 1 radioulna, UF 247356; 7 ilia, UF 247357–247363; 3 vertebrae, UF 247364–UF 247366; 1 urostyle, UF 247367. Description: Anuran ilia could be identified to the genus Lithobates (formerly Rana) due to dorsally expanded iliac blades. REPTILIA Laurenti, 1768 TESTUDINES Linnaeus, 1758 Indet. gen. et sp. Referred Specimens: 2 material fragments, UF 247378, 247620; 1 neural UF 247549. Description: Costal was too damaged to make a positive identific ation of genus. CHELYDRIDAE Schweigger, 1812 Chelydra serpentina Linnaeus, 1758 Referred Specimens: 1 caudal vertebra, UF 247368; 8 peripheral carapace fragments, UF 247369–247375, UF 247550; 2 costals, UF 247376, UF 247377; 1 distal phalanx, UF 247379; 1 right dentary, UF 247380; 1 scapula, UF 247381; 1 left epiplastron, UF 247382; 1 right hypoplastron, UF 247383. Description: The caudal vertebrae found is opisthocoelous and large in size which is characteristic of Chelydra serpentina. The carapace has a distinctly sculptured surface with broad keels. The costiform process on the nuchal bone leaves a suture on the interior surface of anterior peripherals. The distal phalanx has a concave posterior indicating it is Testudines and is wider than most other aquatic turtles. TRIONYCHIDAE Fitzinger, 1826 Apalone ferox Schneider, 1783 Referred Specimen: 1 carapace fragment, UF 247384. Description: The carapace is thin with a sculptured surface which is typical of the family Trionychidae. The carapace fragment was identified as Apalone ferox, the only member of this family present in Florida during the Pleistocene (Hulbert 2001). Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 5 KINOSTERNIDAE Agassiz, 1857 Indet. gen. et sp. Referred Specimens: 4 nuchals, UF 247385–247387, UF 247564; 1 pygal, UF 247389; 3 peripherals, UF 247543, UF 247556, UF 247629; 5 costals, UF 247545, UF 247551, UF 247557, UF 247626, UF 2475630; 3 neurals, UF 247546, UF 247553, UF 247554. Description: The nuchal bone of kinosternids has a broad overlap from the first pleural scute (Meylan 1995). Kinosternon baurii Garman, 1891 Referred Specimen: 1 mandible, UF 247388. Description: Mandible is fully ossified indicating that it came from an adult. It has a smooth surface and is distinctly hooked and matches modern examples of K. baurii. Sternotherus indet. Referred Specimen: 1 costal, UF 247544; 1 right epiplastron, UF 247560. Description: Costal has a developed lateral keel. The epiplastron is very distinct in Sternotherus vs. Kinosternon in having broad medial contact between the anterior humeral scutes (Hutchison and Bramble 1981). EMYDIDAE Rafineqsue, 1815 Terrapene carolina Linnaeus, 1758 Referred Specimens: 2 nuchals, UF 247616, UF 247617; 3 epiplastron fragments, UF 247390, UF 247559, UF 247563; 6 peripheral carapace, UF 247391, UF 247555, UF 247615, UF 247628; 1 xiphiplastron, UF 247392; 2 costals, UF 247568, UF 247625; 3 neurals, UF 247547, UF 247548, UF 247552. Description: Terrapene carolina is the only turtle in North America that regularly fuses the elements of the shell. All specimens identified were broken pieces of fused shells. Terrapene putnami Hay, 1906 Referred Specimen: 1 nuchal, UF 247396; 2 peripherals, UF 247621, UF 247627; 1 right hypoplastron, UF 247562. Description: Shell elements are larger than what is typical for T. carolina. Pseudemys nelsoni Carr, 1938 Referred Specimens: 1 right dentary, UF 247393; 1 costal, UF 247394. Description: The dentary of Pseudemys nelsoni is strongly denticulate and flat ventrally. The costal has deep parallel grooves on the exterior of the shell and the interior surface of the costal contains a thick buttress that connects the plastron to the carapace. Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 6 Trachemys scripta Thunberg in Schoepff, 1792 Referred Specimen: 1 peripheral, UF 247624; 1 nuchal 247619. Description: The carapace has a rugose, sculptured texture and shell pieces are very thick. Nuchal has pronounced midline keel. TESTUDINIDAE Batsch, 1788 Hesperotestudo crassiscutata Leidy, 1889 Referred Specimen: 1 osteoderm, UF 247397; 2 plastron fragments, UF 247398, UF 247399. 1 costal UF 247618; 1 peripheral, UF 247623; 1 nuchal, UF 247395. Description: The osteoderm has a conical shape and is large in size. Although the plastron fragments are in poor condition they are identified on the basis of their very large size and thickness which indicates that they are from the large land tortoise, Hesperotestudo crassiscutata. SQUAMATA Scopoli, 1777 POLYCHRIDAE Anolis carolinensis Voigt, 1832 Referred Specimen: 1 right dentary with 8 teeth, UF 247400. Description: This well-preserved specimen contains eight teeth (Fig. 3). The teeth are tricuspid, which is a characteristic not associated with other lizard species living in Florida during the late Pleistocene. COLUBRIDAE Oppel, 1811 COLUBRINAE Oppel, 1811 Drymarchon corais Fitzinger, 1843 Referred Specimens: 8 vertebrae, UF 247401–247407, UF 247519. Description: The vertebrae of Drymarchon corais are rather large in size with a pronounced haemal keel and a beveled neural spine (Meylan 1995). Figure 3. The medial view of a right dentary from Anolis carolinensis (UF 247400). Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 7 LAMPROPELTINAE Dowling, 1975 Pantherophis guttatus or P. alleghaniensis Referred Specimens: 2 vertebrae, UF 247408, UF 247409. Description: The haemal keel is narrow and straight with moderately developed subcentral ridges (Meylan 1995). NATRICINAE Bonaparte, 1838 Nerodia indet. Referred Specimens: 6 vertebrae, UF 247414–247419. Description: Based on the long, blade like hemal keel, these vertebrae are clearly Nerodia, but due to damage could not be specifically identified. Nerodia cyclopion or N. taxispilota Referred Specimens: 4 vertebrae, UF 247410–247413. Description: These vertebrae have the blade like haemal keel that distinguishes them as Nerodia. The neural spine is taller than the centrum which indicates that they are most likely N. cyclopion or N. taxispilota (Hulbert 2001). Regina alleni Garman, 1874 Referred Specimens: 3 vertebra, UF 247420–247422. Description: These vertebrae have a sigmoid shaped hyapophysis and thin accessory processes. R. alleni is the only member of this genus to have an accessory process of this type (Meylan 1995). Thamnophis sirtalis or T. sauritis Referred Specimens: 4 vertebrae, 247423–247426. Description: These vertebrae have well-developed hypapophyses but the centrum is longer than wide and they have long accessory processes, which distinguishes them from water snakes (Nerodia). XENODONTINAE Cope, 1859 Farancia abacura Holbrook, 1836 Referred Specimens: 9 vertebrae, UF 247427–247435. Description: The trunk vertebrae all have a short neural spine with a dorsoventrally compressed neural arch, and the haemal keel is wide and flat. VIPIRIDAE Oppel, 1811 Indet. gen. et sp. Referred Specimens: 5 vertebrae, UF 247436–247440. Description: These vertebrae were too damaged to be positively identified. However, the wide base of the hyapophysis indicates that they are from a venomous snake. They most likely represent the genus Crotalus or Agkistrodon. Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 8 Crotalus adamanteus Palisot de Beauvois, 1799 Referred Specimens: 3 vertebrae, UF 247441–247443. Description: The vertebrae were identified as Crotalus adamanteus based on their large size, which could not have been attained by any other species of venomous snake in Florida during the late Pleistocene. The hypapophysis of this species is generally long with a wide base. CROCODYLIA Owen, 1842 ALLIGATORIDAE Gray, 1844 Alligator mississippiensis Daudin, 1801 Referred Specimens: 12 teeth, UF 247444–247455; 1 left jugal, UF 247456; 1 right jugal (juvenile), UF 247457; 1 skull fragment, UF 247458; 5 osteoderms, UF 247459–247463; 1 zygopophysis, UF 247464; 1 metapodial, UF 247465; 2 right angulars, UF 247466, UF 247467. Description: Crocodilian osteoderms are thin sheets of bone with a pitted surface. Dorsal osteoderms have a distinct ridge running down the center. Bones of the skull also have a surface that is deeply pitted but are much thicker than osteoderms. Jugals have a central buttress on the ventral side which connects to the postorbital. The metapodial is concave at the posterior end and slightly curved ventrally. AVES Linnaeus, 1758 CICONIIFORMES Bonaparte, 1854 CICONIIDAE Gray, 1840 Indet. gen. et sp. Referred Specimen: 1 cervical vertebra, UF 247521. ANSERIFORMES Wagler, 1831 ANATIDAE Vigors, 1825 Indet. gen. et sp. Referred Specimens: 1 tarsometatarsus, UF 247535; 1 juvenile right distal humerus, UF 247536; 1 proximal tarsometatarsus, UF 247537; 1 coracoid, UF 247538; 2 scapula, UF 247539, UF 247540. GALLIFORMES Temminck, 1820 PHASIANIDAE Horsfield, 1821 Colinus sp. Referred Specimens: 1 left carpometacarpus, UF 247522. GRUIFORMES Bonaparte, 1854 RALLIDAE Vigors, 1825 Idet. gen. et sp. Referred Specimen: 2 right distal tibiotarsus, UF 247523, UF 247524. Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 9 PASSERIFORMES Linnaeus, 1758 Idet. gen. et sp. Referred Specimen: 1 right humerus, UF 247525. Description: The humerus has a pneumatic fossa with a tiny foramen (Brodkorb 1957). MAMMALIA Linnaeus, 1758 DIDELPHIMORPHA Gill, 1872 Didelphidae Gray, 1821 Didelphis virginiana Kerr, 1792 Referred Specimens: 1 right distal humerus, UF 247468; 1 left distal humerus, UF 247469. Description: The olecranon fossa is large and deep. The entepicondylar foramen is broad, well developed, and shows an oval section characteristic of modern didelphid opossums (Vezzosi et al. 2017). CINGULATA Illiger, 1811 DASYPODIDAE Gray, 1821 Dasypus bellus Simpson, 1929 Referred Specimens: 1 distal phalanx, UF 247470; 5 imbricating osteoderms, UF 247471–247475; 6 buckler osteoderms, UF 247476–247481. Description: The distal phalanx is large and broad for burrowing. Buckler osteoderms have six sides in an uneven hexagonal shape. The dorsal side contains 2–5 foramina where hair follicles once grew (Hulbert 2001). The movable osteoderms are rectangular in shape. Foramina can also be seen in these running along the grooves. PAMPATHERIIDAE Paula Couto, 1954 Holmesina septentrionalis Leidy, 1989 Referred Specimens: 1 caudal osteoderm, UF 247482. Description: Holmesina septentrionalis is an armadillo that is much larger than Dasypus bellus and has larger osteoderms. The caudal osteoderm has a rough mottled appearance and has a central ridge running anteroposteriorly (Edmund 1985). LAGOMORPHA Brandt, 1855 LEPORIDAE Fischer, 1817 Sylvilagus sp. Referred Specimens: 1 right maxilla fragment with P2, UF 247483; partial right maxilla, UF 247484; partial left maxilla, UF 247485; 1 proximal end of femur, UF 247486; 1 right astragalus, UF 247487; 1 2nd left metatarsal, UF 247489; 3 teeth, UF 247490-247492; 2 lower left molars, UF 247541, UF 247542. Description: The teeth of late Pleistocene lagomorphs as with modern forms are hypsodont with simple lophate dentition (Hulbert 2001). Only specimens with the lower third premolar can be identified to the species level. Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 10 Sylvilagus floridanus Allen, 1890 Referred Specimen: Right dentary with p3, m1, and m2, UF 247488. Description: The dentary can be identified as Sylvilagus floridanus based on the p3. The p3 lacks the complex pattern of enamel that is found in S. palustris Hulbert 2001. Sylvilagus palustris Bachman, 1837 Referred Specimen: 1 right p3, UF247526. Description: The p3 enamel is more complex in S. palustris than in S. floridanus (Hulbert 2001). RODENTIA Bowdich, 1821 cf. Peromyscus sp. Emmons, 1840 Referred Specimens: 1 left edentulous mandible, UF 247527. Description: The mental foramen is located very close to the base of the M1 (Starrett 1956). The short coronoid process of the mandible is also indicative of the genus Peromyscus (Ruez 2001). Sigmodon hispidus Say and Ord, 1825 Referred Specimens: 1 right mandible with m2, UF 247528; 1 partial right mandible with m1, UF 247529. Description: There is an S-shaped groove on the occlusal surface of the m1 which is distinct to S. hispidus. Neofiber alleni True, 1884 Referred Specimens: 1 left m1, UF 247530; 1 right m2, UF 247531; 1 partial left mandible with m1, UF 247532; 1 right humerus, UF 247565; 1 right femur UF 247566; 1 upper molar UF 247567. Description: The molar is rootless and occlusally all triangles are closed. The ml has five closed triangles between anterior and posterior loop (Birkenholz 1972). GEOMYIDAE Bonaparte, 1845 Geomys pinetis Rafinesque, 1817 Referred Specimens: 1 right mandible with i1, UF 247533. Description: The mandible is robust. The anterior extent of the masseteric scar lies just ventral to the reentrant of the p4. The position of the mental foramen varies from a point halfway between the masseteric scar and the i1 alveolus, to one-fourth the distance from the scar. The ventral most portion of the scar bulges laterally. The lower incisors are large with a wide, flattened outer surface (Ruez 2001). Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 11 HYDROCHAERIDAE Gray, 1825 Neochoerus pinckneyi Hay, 1923 Referred Specimens: 1 partial incisor, UF 247493. Description: The incisor is far larger than those found in most rodent species living in Florida during the Pleistocene. The notable exception being Castoroides ohioensis, the Giant Beaver. Parallel, longitudinal striations along the incisor lack the prominent grooves associated with C. ohioensis (Hulbert 2001), and most closely resembles N. pinckneyi. CARNIVORA Bowdich, 1821 URSIDAE Fischer de Waldheim, 1817 Idet. gen. et sp. Referred Specimens: 1 proximal end of 4th left metacarpal, UF 247494. Description: The immense size of this metacarpal indicates that it came from one of the two species of cave bear present in Florida during the Rancholabrean, Tremarctos floridanus or Arctodus simus. MUSTELIDAE Fischer, 1817 Lontra canadensis Gray, 1843 Referred Specimens: 1 proximal end of the right femur, UF 247495; 1 distal end of the left tibia, UF 247496. Description: Epiphyses on both specimens were fused showing that the elements were from a mature animal. The limb bones of L. canadensis are short compared to body size (Lariviere and Walton 1998). PROCYONIDAE Gray, 1825 Procyon lotor Linnaeus, 1758 Referred Specimens: 2 right mandibles, UF 247497, UF 247498; 1 right mandible fragment, UF 247499; 1 left mandible fragment with rodent gnawing, UF 247500; 1 right m2, UF 247501; 1 right M1, UF 247502; 1 right humerus, UF 247558. Description: Both molars have a flattened grinding surface with tall cusps for tearing indicative of an omnivore. The lower molar has two roots while the upper has three. SORICOMORPHA Gregory, 1910 Blarina carolinensis Bachman, 1837 Referred Specimens: 1 left edentulous mandible, UF 247534. Description: The mandible is similar in size and morphology to modern forms of Blarina carolinensis. ARTIODACTYLA Owen, 1848 TAYASSUIDAE Palmer, 1897 Mylohyus fossilis Leidy, 1860 Referred Specimen: 1 left DP4, UF 247504. Description: This bunodont tooth is of small size and has an unusual crown. It has been determined as a deciduous premolar from a young Mylohyus fossilis. Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 12 CAMELIDAE Gray, 1821 Palaeolama mirifica Simpson, 1931 Referred Specimens: 1 left p4, UF 247505; 1 partial right mandible, UF 247518. Description: Dentition is relatively brachyodont and the p4 of P. mirifica has four lingual flexids (Webb and Stehli 1995). CERVIDAE Goldfuss, 1820 Odocoileus virginianus Zimmermann, 1780 Referred Specimen: 1 partial right dentary w/m3, UF 247506; 1 large antler base, UF 247507; 1 small antler base, UF 247508; 1 large antler fragment, UF 247509; 2 antler tips, UF 247510, UF 247511; 1 partial tooth, UF 247571. Description: Antlers have a granulated surface which distinguishes them from bone (Gilbert 1990). None of the antlers found were large enough to be identified as elk, Cervus canadensis. BOVIDAE Gray, 1821 Bison cf. antiquus Leidy, 1852 Referred specimen: 1 right M1, UF 247503. Description: This tooth is in poor condition; it has tentatively been identified as B. antiquus. PERISSODACTYLA Owen, 1848 EQUIDAE Gray, 1821 Equus sp. Referred Specimens: 1 DP2, UF 247515; 1 right p2, UF 247516; 1 incisor, UF 247517; 1 phalanx 3, UF 247520. Description: Equus has hypsodont teeth that are very large (Fig. 4). The complex grinding surface and large size of the teeth indicate that these specimens come from an Equus species. The upper molars have a square shape while lower molars are more rectangular. TAPIRIDAE Gray, 1821 Tapirus veroensis Sellards, 1918 Referred Specimen: 1 partial lower tooth, UF 247512; 1 partial upper molar UF 247513; 1 partial lower molar UF 247514. Description: Tapirus veroensis is smaller in size compared to T. haysii and is the only species of tapir that lived in Florida during the late Pleistocene (Hulbert 2003). All tapirs have brachyodont teeth with very distinct cusps. URANOTHERIA Simpson, 1945 ELEPHANTIDAE Gray, 1821 Mammuthus columbi Falconer, 1857 Referred Specimens: 1 partial cheek tooth, UF 322983. Description: Although damaged, this tooth can be identified to M. columbi and not M. haroldcooki by its thinner enamel and lack of crenulation (Hulbert 2001). Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 13 Discussion Biostratigraphic indicators Including both modern and extinct species, 38 vertebrate species have been recorded at Zeta Pond, and all are known to have lived in Florida during the late Pleistocene. The fossil remains of Amphiuma means, Anolis carolinensis, Sigmodon hispidus, and Didelphis virginiana have all been recovered from the site and are animals that still live in Florida today. Extinct fauna include Hesperotestudo crassiscutata, and Holmesina septentrionalis, both of which are not recorded from Florida until the middle or late Pleistocene and disappear by the end of the epoch. The presence of modern fauna shows that this site is relatively young in age. There are species present that have not been found in Florida until the late Pleistocene which restricts the age of the Zeta Pond Site to the Rancholabrean NALMA (North American Land Mammal Age). This land mammal age encompasses the middle to late Pleistocene and ends when the Holocene begins (300,000–10,000 BP). The amphibian, Amphiuma means, is a species that has only been found in Rancholabrean deposits or younger. Amphiuma is the only living genus of the Family Amphiumidae, and while there are some records of an Amphiuma species from the Miocene, the species Amphiuma means has not been recorded in Florida until the Rancholabrean (Holman 2006). Among the mammals found at the site, the Cotton Rat, Sigmodon hispidus, is the clearest indicator that Zeta Pond cannot exceed 300,000 years in age. It is at the end of the Irvingtonian NALMA that S. hispidus replaces S. bakeri in the fossil record and it has been called the “herald” of the Rancholabrean (Martin 1969). The large species of armadillo found at Zeta Pond, Holmesina septentrionalis, belongs to the Family Pampatheriidae. Pampatheres are a good indicator of the age of a fossil site because the overall trend in their Figure 4. Equus sp., right p2 in occlusal view (UF 247516). Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 14 evolution in the Pleistocene was an increase in body size. This trend is made clear within Holmesina as specimens of H. floridanus get larger throughout the Irvingtonian until, by the start of the Rancholabrean, the average body size of the animal had reached six feet in length. This larger form was named a new species, H. septentrionalis (Edmund 1985), and its massive size is demonstrated by the osteoderm found at Zeta Pond. Among the extinct mammalian herbivores found, the tapir Tapirus veroensis, is a species that only existed in the middle-late Pleistocene in Florida. Tapirs lived in the state from the late Miocene to the end of the Pleistocene, but at the start of the Rancholabrean, T. veroensis was the only living member of the genus in the state (Hulbert 2003). Florida has a rich fossil record and Zeta Pond’s fauna can be compared to many other Pleistocene sites in the state. There are two in the Tampa Bay Area that are close in age but demonstrate the differences in early Pleistocene and late Pleistocene faunas. Seminole Field is a late Pleistocene fossil site in Pinellas County discovered in the 1920’s and has a faunal list very similar to that from Zeta Pond. There are many species that occur at both sites but those most indicative of Rancholabrean age are: Amphiuma means, Holmesina septentrionalis, Sigmodon hispidus, and Tapirus veroensis (Table 1). In neighboring Hillsborough County, the Leisey Shell Pit 1A site has a faunal list containing species from the early Pleistocene and demonstrates the clear differences in fauna found in the Irvingtonian NALMA. Amphiuma means is not reported from the site. Instead of the tortoise Hesperotestudo incisa the site contains H. mylnarskii a similar sized tortoise that is replaced by H. incisa in the middle Pleistocene. S. libitinus is the species of Cotton Rat reported from Leisey Shell Pit 1A. This is replaced by S. bakeri in the middle Pleistocene, and S. hispidus replaces S. bakeri at the start of the Rancholabrean. The tapir T. haysii is replaced with T. veroensis by the middle Pleistocene. Given the fossil evidence found at Zeta Pond in comparison to other sites in West-central Florida, it is clear that this new fauna that can be no older or younger than Rancholabrean in age. It represents a unique time in Florida’s history that contained fauna very familiar to us today, like river otters, opossums, and white-tailed deer, coexisting in an ecosystem that included what now would be very unfamiliar animals like giant land tortoises, short-faced bears, and mammoths. Paleoecology: Marsh habitat The large number of fossils from Zeta Pond that represent species known to live in aquatic environments indicate that the fauna was likely deposited in a freshwater marsh. Most of the fossils are from aquatic or semi-aquatic amphibians and reptiles with almost one third of specimens belonging to the Class, Caudata. The most common amphibian species are the two large, highly aquatic salamanders, Amphiuma means and Siren lacertina. Both live in slow moving water and burrow into the mud where fossilization is likely to occur. Both species survive in Florida today and are still found in Pinellas County (Ashton and Ashton 1988). Anuran fossils were also found at the site but are mostly represented by broken ilia and humeri. These fossils were too damaged for species identification but were intact enough to place them in the genus Rana, a group of aquatic frogs. Among the reptiles, specimens belonging to the order Testudines were most common. The majority were aquatic turtles, Chelydra serpentina being the most common among them. The frequency of this species can be attributed to the fact that it is highly aquatic, even when compared to other turtles. It is rarely found basking on logs and prefers to float in the water to sun itself. Mud and musk turtles of the family Kinosternidae were another common element of the fauna and are also highly aquatic. Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 15 Many snake vertebrae recovered from Zeta Pond represent aquatic or semi-aquatic taxa such as Thamnophis, Farancia, and Nerodia, all of which are present in the modern fauna and are known to frequent freshwater habitats like streams, ponds and marshes. Farancia is a common element of the fauna, perhaps due to the fact that they burrow through bottom muck hunting amphiuma and siren. Most vertebrae from the family Viperidae were too damaged to be identified to species but some most likely belong to the Cottonmouth, Agkistrodon piscivorus which is associated with freshwater ecosystems. As is expected in a freshwater deposit in Florida, Alligator mississippiensis was one of the most common reptiles found. Many skull fragments were recovered as well as teeth and osteoderms. The presence of this species helps to confirm that Zeta pond was a freshwater habitat. Rodentia and Lagomorpha are the most common mammalian taxa found at Zeta Pond. Among the lagomorphs, many specimens can be assigned to the genus Sylvilagus, but could not be conclusively identified as S. palustris (marsh rabbit) or S. floridanus (cottontail). One p3 has been identified as belonging to the species S. palustris due to the amount of folding on the enamel (Morgan and White 1995). Sylvilagus palustris is adapted to wetland habitats and is currently only found in close vicinity to brackish or freshwater environments. Rodentia species are highly adapted to specific habitats and can be good indicators of past environments. Neochoerus pinckneyi is a species of capybara found at the site and is Table 1. Comparison of biostratigraphically useful species found from fossil sites Seminole Field, Leisey Shell Pit 1A, and Zeta Pond that most clearly demonstrate age. Species present is indicated by “+”. Species absent from the fossil site are indicated by “−”. Fossil Sites Leisey Shell Pit 1A Seminole Field Zeta Pond Order Caudata Amphiuma means − + + Order Testudines Hesperotestudo mylnarskii + − − Hesperotestudo incisa − + − Order Didelphimorpha Didelphis virginiana − + + Order Edentata Holmesina floridanus + − − Holmesina septentrionalis − + + Order Carnivora Arctodus pristinus + − − Order Rodentia Sigmodon libitinus + − − Sigmodon hispidus − + + Order Perissodactlya Tapirus haysii + − − Tapirus veroensis − + + Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 16 very similar to the living South American species, Hydrochoerus hydrochaeris. Capybaras are large, highly aquatic rodents that currently live in marshes and swamps (Reid 1997), and there is no evidence to suggest that this was any different in the Pleistocene. Neofiber alleni is currently found exclusively in freshwater marshes in Florida and southeast Georgia and is good evidence that the Zeta Pond site represents a freshwater marsh. Fossils belonging to the cohort, Aves were recovered from the site, but most could not be identified beyond family. However, much of the material can be assigned to the family, Anatidae, which represents the aquatic family including ducks and their relatives. Fossils of both Chondrichthyes and Teleostei were found at Zeta Pond, but have yet to be identified. Preliminary identification, however, suggests that the specimens are from both marine and freshwater species. This may suggest that the site underwent periodic mixing with salt water or that some fill sediment has been mixed into the site. Further examination of the fish jaws and scales found is needed to determine how many species of fish are from fresh, marine, or brackish habitats Paleoecology: Evidence for Upland Habitat The number of fossils representing species that lived in pine forest and other upland habitats is small and far outnumbered by specimens representing a marshland ecosystem. Limited evidence of common grazing mammals suggests that Zeta Pond during the Rancholabrean was not suitable for them. It is suspected that elements found from these species survived transportation to the site locality through fluvial means; however, the number of species recorded from the site that lived in dryer habitat suggests that there was an adjacent upland environment. Among reptiles, multiple specimens belonging to the giant tortoise, Hesperotestudo crassiscutata, are recorded from the site. Little research has been done on the ecological requirements necessary for such a large tortoise living in Florida, but it most likely had a lifestyle similar to modern giant land tortoises. Aldabrachelys gigantea, the Aldabra Tortoise, occurs on the Aldabra Atoll and recent studies indicate that the highest population densities of A. gigantea are found in coastal scrub and open mixed scrub environments (Turnbull et al. 2015), habitats that are predominantly made up of shrubs and grasses. H. crassiscutata is morphologically very similar to A. gigantea and likely required a similar open scrub, seasonally dry habitat to graze. Among the rodents recorded at Zeta Pond, the majority of species live in wetland habitats. There are two, however, that indicate other environments. Geomys pinetis is a species of pocket gopher that, like the Gopher Tortoise G. polyphemus, requires dry sandy soil to dig its burrows. The southern short-tailed shrew, Blarina carolinensis, is less restrictive in habitat requirements but is not common in areas with saturated soil. It is found mostly in well drained habitats like grassland and pine forest (McCay 2001). Specimens of large grazing mammals are rare at the Zeta Pond Site, but among those found the majority belonged to the genus Equus. Species identification of Equus specimens is difficult in the Pleistocene and cannot be made on isolated teeth and bones. Horses as a group however, made an evolutionary shift towards grazing in the Miocene and by the late Pleistocene had developed large hypsodont teeth ideal for breaking down tough grasses (Hulbert 2001). The resiliency and large size of Equus teeth made them more likely to survive transport to Zeta Pond and for fossilization to occur. Mammuthus columbi, at Zeta Pond suggests that this species was also a grazing specialist. An almost complete skeleton of M. colombi was recovered in Utah in 1988 along with plant and dung material. Study of the material indicated that the mammoth’s diet Eastern Paleontologist J.H. Pammer, P.A. Meylan, and R.C. Hulbert 2024 No. 11 17 consisted mostly of grasses, brush and trees (Gillette and Madsen 1993). This suggests that M. columbi had a lifestyle similar to modern African elephants which occur in arid regions around Africa and prefer scrubland and woodland habitat. The rich fossil evidence that Zeta Pond has provided gives a unique look at Florida life in the Rancholabrean. The 38 species currently recorded allows reconstruction of the landscape as a freshwater marsh with an adjacent upland habitat and shows that the area around Eckerd College hosted a complex ecosystem during the Rancholabrean. The site represents a time period in Florida when biodiversity was at its peak. Faunal immigrants from South America, Africa and Europe all found their way to Florida at this time to form a paleo-environment that is hard to imagine in current North America. Acknowledgements Thanks are due to Dr. David Steadman for identifying all the avian fossils, to Jason Bourque for identifying much of the turtle material, to Barbara Fite for providing literary sources, and to Eckerd graduates, Kieley Hurff, Kasey Kilbride, and Trey Kieckhefer, for their help in collecting fossil specimens. Publication costs supported by the Eckerd College Natural Sciences Collegium. 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