Tortoises
after the flood
chad arment (2025)
Tortoises are terrestrial chelonians of the family Testudinidae, found on all continents except Australia and Antarctica. Quite a few (living and extinct) are or were island endemics. In the fossil record, tortoises are only known from Cenozoic deposits, which has interesting implications for their place within the creation model.
Within the secular model, tortoises and near fossil kin (Pan-Testudinidae) are placed in a larger superfamily, the Testudinoidea. This includes some extinct Asian turtle families and the living families Emydidae (pond turtles, terrapins, box turtles), Platysternidae (big-headed turtle), and Geoemydidae (pond and river turtles, Asian box turtles). Genetic and morphological analysis pairs the Testudinidae with the Geoemydidae (referred to as the clade Testugaria) (Meylan 2006). The secular model posits the Cretaceous aquatic to semi-aquatic turtle family Lindholmemydidae in Asia as the origin for the Testudinoidea, though there is still debate over where the Testudinidae first appeared (Lichtig and Lucas 2016).
Because the first true fossil tortoises are found in Eocene deposits, the creation model has a couple of possible scenarios for pre- and post-Flood tortoise biogeography, depending on whether the baraminic kind is primarily familial or superfamilial. First, if tortoises as such existed before the Flood and are simply unrecorded in Cretaceous or lower Flood deposits, then a single pair of tortoises (basal Testudinidae or something closely related) survived on the Ark. (We will look at hybridization support for a single baramin in the family later.) Their descendants would have spread first throughout the Old World, then into the New World. An alternative scenario would be if tortoises had their origin in an aquatic pre-Flood turtle clade. In that scenario, tortoises would be a terrestrial divergence in the post-Flood world. Their ancestral origin group would have survived the Flood outside the Ark, and could have landed anywhere once the Flood waters subsided.
Both the Emydidae and Geoemydidae, while mostly made up of aquatic species, include turtles adapted to semi-aquatic and terrestrial habitats: North American box turtles, Asian box turtles, the North American wood turtle, and Neotropical wood turtles. This suggests that, if the tortoise’s baraminic kind is at the superfamilial level, trajectories towards terrestrialism are not out of the ordinary.
The early history of tortoises, regardless of whether we are looking at the secular or the creation model, is sparse. In North America, Hadrianus is known from early Eocene (late Wasatchian) deposits in Wyoming and New Mexico, while in France, Fontainechelon is known from a slightly younger Eocene (MP 10) deposit. Lichtig et al. (2021) suggested that the Testudinidae first appeared around the Paleocene-Eocene in North America, then emigrated to Asia and Europe. This does seem to fit with the genetic relationships of extant tortoises, where the North American Gopherus and the Asian Manouria are both basal to other living tortoises (Le et al. 2006). All other living tortoises appear to be part of later radiations out of Africa. However, Carbot-Chanona et al. (2023) note that their testudine trait analysis supported a European origin, with early spread to North America, and possibly secondary radiation of basal forms from North America back to the Old World. Interestingly, a fossil tortoise is known from Eocene strata on Ellesmere Island, in the High Arctic, suggesting a climate-compatible early Cenozoic pathway from Europe to North America. This fossil tortoise has been reported variously as Hadrianus or Manouria (Dawson et al. 1976; Eberle and Greenwood 2012; Franz 2014), but Vlachos (2018) simply refers to it as indeterminate. More fossil evidence will be necessary to clear up this biogeographic question. In any case, tortoise diversification rates appear to have been very high in both the Eocene and Miocene (Vlachos and Rabi 2018), likely due to climatic shifts during the post-Flood period leading up to the Ice Age.
Within North America, besides the early-middle Eocene Hadrianus (which may be considered a sister group to other testudinids [Vlachos 2018]), early tortoises included Stylemys, Oligopherus, Cymatholcus, and “Testudo” brontops appearing in the late Eocene, “Testudo” costarricensis in the late Oligocene, and Gopherus and Hesperotestudo (and possibly Floridemys, more closely related to the South American tortoises [Vlachos 2018]) in the Miocene (Jiménez-Hidalgo et al. 2015; Lichtig et al. 2021; Carbot-Chanona et al. 2023). Today, only Gopherus survives. Gopherus was a basal offshoot, while the others were closer in relationship with Asian and European genera (e.g., Stylemys capax forming a clade with Ergilemys insolitus, Cheirogaster maurini, and Taraschelon gigas [Carbot-Chanona et al. 2023]). The monophyletic genera Gopherus, Hesperotestudo, and Stylemys did not have close relationships (the latter two were more derived), and are considered a polytomy, or (nearly) simultaneous divergence, pending further evidence (Vlachos 2018).
Hadrianus majusculus
Eocene, New Mexico
(1904)
Hesperotestudo crassiscutata
This is a Pleistocene Florida fossil that
measured approximately 44 inches in length.
(Loomis 1927)
Stylemys
Oligocene, White River Badlands
In Europe, the Eocene saw Fontainechelon, Pelorochelon, and Cheirogaster, while the Oligocene brought Taraschelon gigas, though the latter’s close relation to Cheirogaster maurini may indicate generic synonymy (Pérez-García et al. 2016; Vlachos and Rabi 2018; Chroust et al. 2025). Titanochelon appeared in the Miocene and survived until the early Pleistocene, ranging from the Iberian Peninsula to Turkey (Pérez-García and Vlachos 2014; Pérez-García et al. 2017a; Pérez-García et al. 2017b; Karl et al. 2021; Vega-Pagán et al. 2025). Cheirogaster and Titanochelon were both very large tortoises, but were not closely related to each other, and neither were part of the same lineage as the later and still extant Centrochelys of northern Africa (Vlachos and Rabi 2018). The basal Manouria first appeared in the early Miocene in Czechia, possibly derived from a Pelorochelon relation, after which it dispersed to Asia, where it is extant today (Chroust et al. 2025). Alatochelon of Pliocene Spain was a large tortoise closely related to and likely derived from Centrochelys of Africa (Pérez-García et al. 2020). A large tortoise, Solitudo, has been described from Pleistocene remains in a cave in Sicily, part of a clade of insular tortoises also found on Menorca and Malta, likely from a Mediterranean radiation dating to the Miocene (Valenti et al. 2022; Georgalis et al. 2025).
In Africa, Gigantochersina is known from the late Eocene-early Oligocene of Egypt (Chroust et al. 2025), likely emerging from Eurasian origins via the “Iranian route” of trans-Tethyan dispersal (Georgalis et al. 2021). Miocene fossil appearances included the extinct Impregnochelys and Namibchersus, as well as the extant Stigmochelys (leopard tortoise), Kinixys (hinge-back tortoises), and Centrochelys (spurred tortoise) (Harrison 2011; Vlachos 2025). The Miocene European Titanochelon appears to be a sister genus to Stigmochelys and may have dispersed from Africa to Europe (Vlachos 2025). Within modern tortoise genera of southern Africa, genetic analysis posits that Kinixys was an early Paleogene offshoot of a clade incorporating the Malagasy tortoises (below), and the subclades Psammobates (tent tortoises) + Stigmochelys, Chersobius (five-toed padloper) + Chersina (angulated tortoise), and Homopus (four-toed padloper) (Hofmeyr et al. 2017). Morphological and genetic evidence places the East African pancake tortoise, Malacochersus, with its unique flattened shell, alongside the Testudo + Indotestudo clade (Moll et al. 2021). Testudo is made up of species in the Mediterranean region of southern Europe and northern Africa, into western Asia, while Indotestudo is primarily in southeast Asia. Testudo is today distinguished by three subgeneric groups: Testudo [Agrionemys], the Russian tortoise; Testudo [Chersine], Hermann’s tortoise; and Testudo [Testudo], the Greek, Egyptian, and marginated tortoises. Each of these three lineages can be distinguished separately in the fossil record going back to Miocene strata (De Lapparent de Broin et al. 2006). Additional Miocene Testudo lineages in Europe appear to have gone extinct (Corsini et al. 2014; Luján et al. 2016; Pérez-García et al. 2021), suggesting an initial burst of diversification winnowed down to a few lineages today.
Testudo graeca
Algiers
Karim Attouche
Endemic Malagasy tortoises (Astrochelys and Pyxis) are most closely related to South African genera, likely diverging in the Eocene (Hofmeyr et al. 2017). Parsimony would seem to favor their divergence from a single source population after arrival to Madagascar (via marine crossing), though there is no fossil evidence one way or the other.
The Seychelles are a group of islands east of Africa and north of Madagascar. These were colonized by a giant tortoise, Aldabrachelys, best known from the coral atoll Aldabra in the Outer Islands of Seychelles. Two extinct species of Aldabrachelys are known from Madagascar, indicating that they originated there, and genetic analysis demonstrates a close relationship to the Malagasy endemic tortoises (Palkovacs et al. 2002). Current direction and dispersal of other reptiles from Madagascar to the Seychelles supports this (Austin et al. 2003). Aldabra is known to have been completely submerged at least twice since it was first colonized by tortoises, suggesting that tortoises arrived there three separate times (Arnold 1976). As one author has noted, “It could be argued that a variety of animals and plants were continuously shed from the Madagascar coastline but their chances of a successful landfall and survival were far greater during some periods than others” (Braithwaite 2016). Human-mediated dispersal has been debated in the origin of these tortoises throughout the Seychelles, but it is clear that they originally arrived prior to human colonization. Once some island populations were eradicated, however, as tortoises were killed and eaten, Aldabra became a source population for later reintroduction, with “large quantities of giant tortoises . . . shipped between different islands” in the 18th and 19th centuries (Kelhmaier et al. 2023).
Five species of giant tortoises were endemic to the Indian Ocean Mascarene islands, east of Madagascar, hunted to extinction by the mid-1800s. Two were found on Mauritius, two on Rodrigues, and one on Réunion. These tortoises made up a monophyletic genus, Cylindraspis, deeply divergent from other tortoises and not closely related to species in Madagascar or other Indian Ocean islands. The source population likely arrived overwater from Africa (Kehlmaier et al. 2019). The lack of predators allowed adaptations away from a ‘defensive’ morphology, including the independent development of ‘saddlebacked’ shells on all three islands (Austin and Arnold 2001). Today, Aldabra tortoises have been introduced as part of rewilding efforts, as giant tortoises were an important ecological fixture; for example, aiding germination of Mauritian ebony trees by passing seeds through their digestive system (Gerlach et al. 2013).
In Asia, there are a number of dubiously referenced Eocene genera, including ‘Hadrianus’ and Ergilemys, that appear to require critical revision (Chroust et al. 2025). Protestudo is known from the Miocene. Also from the Miocene, and extending into the Plio-Pleistocene, was the largest tortoise to have ever lived, Megalochelys (formerly Colossochelys). It ranged from the Siwaliks of India to southeast Asia (Badam 1981; Setiyabudi 2009; Naksri et al. 2019; Vlachos 2019). The extant elongated tortoise, Indotestudo elongata, is found throughout southeast Asia and in neighboring regions (closely related to the Mediterranean Testudo), yet despite significant biogeographical barriers is genetically homogenous across its range. Ihlow et al. (2024) suggested that extensive human-mediated traffic (with tortoises as an easily-carried food source) may be responsible. Geochelone was once a wastebasket taxon, but today comprises two species of star tortoises found primarily on the Indian subcontinent and in Myanmar (Kundi et al. 2023). Among living tortoises, Geochelone is genetically most closely related to the African genus Centrochelys (Kehlmaier et al. 2019).
The living South American tortoises (Chelonoidis) are genetically much closer related to African genera, specifically the Centrochelys sulcata clade (Kehlmaier et al. 2017), than to the North American tortoises such as Gopherus or Hesperotestudo. This points to a trans-Atlantic dispersion, with tortoises reaching South America by the first fossil appearances in the late Oligocene (Carbot-Chanona et al. 2023). All fossil tortoises in South America are referable to Chelonoidis, found in numerous deposits throughout the continent (De la Fuente et al. 2018). Chelonoidis includes the living red-footed, yellow-footed, Chaco, and Galapagos tortoises, along with an extinct radiation in the Caribbean. Some fossil tortoises discovered on the mainland of South America are considered ‘giant’ in size, similar to the Galapagos tortoises (Zacarías et al. 2013; Vlachos et al. 2023).
For creationists, the family level is a reasonable minimum boundary for the tortoise’s baraminic kind. The kind may encompass more than the family, but at a minimum, it includes the family. Key evidence for this is hybridization within the family. Intergeneric hybrids of tortoises are unlikely in the wild, but Centrochelys x Stigmochelys (‘leopcata’), Centrochelys x Chelonoidis (‘redcata’), Stigmochelys x Chelonoidis, and Chelonoidis x Astrochelys hybrids have been produced in the pet and exhibit trades, with extensive documentation in various social media groups dedicated to tortoise hybrids. This directly connects tortoises from Africa, Madagascar, and South America.
Marine dispersal
Long-distance dispersal by tortoises, overwater, is well-recognized in the secular model and fits neatly into the creation model. As noted by Austin et al. (2003): “Their buoyancy predisposes them to such journeys, as do the position of the lungs near the top of the shell, which makes them self-righting in water, and their long necks, which permit them to keep their heads well above the water surface and so breath easily.” Meylan and Sterrer (2000) noted: “They are not strong swimmers but float well, and can survive in water for considerable lengths of time. . . . Their adaptations to the osmotic stress of xeric environments apparently serve them well when they find themselves exposed to the marine environment.”
Not only are there numerous cases of island endemics, and the evidence of trans-Atlantic colonization of South America from Africa, there is a confirmed case of an Aldabra tortoise washing ashore the east coast of Africa (Gerlach et al. 2006). The tortoise was found walking out of the sea, emaciated, and covered in goose barnacles. Gerlach et al. (2006) notes additional records of Aldabra tortoises discovered at sea, and one apparent instance of colonization of tortoise-less Esprit island, between 1975 and 2000.
Besides the overwater dispersal and radiation of Chelonoidis in the Galapagos islands (still extant) and in the Caribbean islands (extirpated), Aldabrachelys in the Seychelles, Cylindraspis in the Mascarenes, the endemic Malagasy tortoises, and Testudo in the Mediterranean islands, there are a few additional cases of island tortoises worth noting. The North American Hesperotestudo (Miocene-Pleistocene) is found in fossil form extensively throughout the North American continent, but has also been found in Pleistocene strata on Bermuda (Meylan and Sterrer 2000; Olson and Meylan 2009). Unique characters supported recognition of the Bermuda specimens as a distinct species. The volcanic islands of the Cape Verde archipelago off the Senegal coast once hosted an endemic tortoise, still undescribed, with Miocene fossil eggs discovered on Maio Island and younger bones found on Sal Island (Kehlmaier et al. 2021). The Canary Islands also hosted tortoises, with several species named, but these require further taxonomic assessment in their relationship to extant genera (Sánchez-Marco et al. 2025).
While their expansion has not resulted in endemics, two Asian tortoises (Manouria, Indotestudo) are found on various islands in Indonesia. A Pleistocene tortoise identified as Megalochelys was found in Central Java, Indonesia (Setiyabudi 2009).
giant tortoises
The largest living tortoises are the Galapagos tortoise and Aldabra tortoise. The Galapagos tortoise reaches 1.3 m in carapace length, the Aldabra tortoise reaches 1.2 m, while the largest recently-extinct Mascarene tortoise reached 1.1 m (Itescu et al. 2014). The extant genus Gopherus had a fossil member (‘hexagonatus’) with a carapace length greater than 1 m (Esker et al. 2019). Fossil ‘giant’ tortoise genera with at least one species having a shell longer than 1 m, included Pelorochelon, Hadrianus, Hesperotestudo, Megalochelys, and Titanochelon (Vlachos and Rabi 2018). Hesperotestudo crassiscutata from Pleistocene Central and North America reached 1.5 m (Itescu et al. 2014), while Megalochelys reached up to 2 m. One fossil tortoise from Mexico, ‘Stylemys’ gisellae, had a 92 cm carapace length (Carbot-Chanona et al. 2023), so potentially could have reached 1 meter. Fossil Chelonoidis shell fragments from Miocene Colombia indicate tortoises the same size as the Galapagos tortoises (Cadena and Jaramillo 2015). (There is a difference between a straight-line carapace length and a curved carapace length, and some published measurements do not necessarily distinguish, so caveats apply.)
While it is certainly interesting that several known island radiations involve giant tortoises, evidence from both living and fossil tortoises indicates that these are not, in fact, examples of the ‘island rule,’ where some island endemics develop into ‘giants’ or ‘dwarfs’ compared to their mainland relations (Itescu et al. 2014; Vlachos and Rabi 2018). For one thing, most of the island tortoises have just as large, if not larger, relations (extant or fossil) on the closest continents. It is also possible there is a survivorship bias in that larger tortoises are more likely to survive a long ocean journey, contributing to a founder effect.
Megalochelys sp.
Paleontologist Barnum Brown works on
the shell, unearthed in the Siwalik Hills of India,
shown with a modern tortoise (Galapagos?)
skeleton underneath.
(1926)
Tortoises and the Post-Flood Climate
This article assumes a lower Cenozoic Flood boundary for reasons I have noted elsewhere, though of course the fossil record of tortoises supports that, with at least nine genera of tortoises being found on both sides of the Plio-Pleistocene boundary. If only one pair of tortoises were on the Ark (as an unclean kind), only one genus of tortoises should be found on both sides of that boundary, which is often suggested by upper Cenozoic Flood boundary proponents.
But another aspect raised by certain upper Cenozoic Flood boundary proponents are alleged cases of ‘tropical’ animals and plants in lower Cenozoic strata where today we would see temperate species. Part of the problem is that those who hold to an upper Cenozoic Flood boundary do not fully recognize the climatic shifts that occurred in the immediate post-Flood period. They essentially dismiss a massive amount of data from the secular literature in favor of what has rightly been termed ‘back-of-the-napkin’ calculations. Creation science is still in the early days of understanding post-Flood climate shifts—as I was told by one Ph.D. specialist, we need more computing power.
Still, we can chip away at one of the more baseless arguments. One creationist has argued that tortoises would not be found at higher latitudes in the post-Flood world, so Eocene tortoise fossils of Ellesmere Island (Dawson et al. 1976) or Miocene Hesperotestudo fossils from the Yukon Territory (Eberle et al. 2019) would be pre-Flood reptiles that died in the Flood. Within a lower Cenozoic Flood boundary model, the Eocene and Miocene would have been warmer at higher latitudes than we find today, but would still have seasonal temperature changes—and of course the High Arctic would have had months of darkness.
Today, modern giant tortoises can find difficulty in acclimating to sudden extreme environmental changes, which led to faulty paleoclimatological models even in the early secular literature (Moll and Brown 2017). Several smaller to moderate-sized tortoises, however, do ‘hibernate’ (technically brumate) during the winter, including Gopherus and Testudo (Ultsch 2006). But could a larger tortoise have survived at higher latitudes with at least temperate-level climate in the post-Flood world?
It turns out there is a tortoise genus, Hesperotestudo, with some very large species, that not only lived at higher latitudes in the Miocene and Pliocene, but also in the Pleistocene (Moll and Brown 2017; Brown et al. 2018; Esker et al. 2019). During the Pleistocene, Hesperotestudo’s range in North America included the southeastern, southwestern, and Great Plains states, but also reached eastern Pennsylvania (the Port Kennedy Bone Cave at Valley Forge), Missouri, and southern Illinois (Brown et al. 2018). So, clearly, a large tortoise was capable of adapting to temperate climate with seasonal winters. Adaptations to colder temperatures can be morphological or behavioral. A thicker shell with a flared posterior border, large amounts of body fat, and dermal ossicles on limbs are morphological adaptations to conserve body heat, while sheltering in burrows, caves, or crevices are possible behavioral adaptations (Moll and Brown 2017). Many giant tortoises today are known to be capable of surviving months without food or water (they were often taken on whaling ships and kept alive on voyages to be butchered for food as needed). Cryoprotection and gigantothermy are known in other turtles, so cannot be ruled out as possible adaptations for fossil tortoises.
Tortoises were designed to adapt and diversify to a wide range of environments as they spread around the world after the Flood. Their capacity for dispersal is unmatched by most baraminic kinds that relied on land bridges. Their morphological diversity, small to giant, ‘pancaked’ to high-domed, with an array of colors and patterns, makes them the perfect ambassadors for creation biology. So the next time you visit a zoo to look at the giant tortoises, you will be able to recognize them not as some stodgy relics of a prehistoric world, but as the well-adapted branches of recent diversification in the post-Flood world.
references
Arnold, E. N. 1976. Fossil reptiles from Aldabra atoll, Indian Ocean. Bulletin of the British Museum (Natural History) Zoology 29(2): 85-116.
Austin, J. J., and E. N. Arnold. 2001. Ancient mitochondrial DNA and morphology elucidate an extinct island radiation of Indian Ocean giant tortoises (Cylindraspis). Proceedings of the Royal Society of London B 268: 2515-2523.
Austin, J. J., E. N. Arnold, and R. Bour. 2003. Was there a second adaptive radiation of giant tortoises in the Indian Ocean? Using mitochondrial DNA to investigate speciation and biogeography of Aldabrachelys (Reptilia, Testudinidae). Molecular Ecology 12: 1415-1424.
Badam, G. L. 1981. A giant tortoise from the Upper Siwaliks of North India. Bulletin of the Deccan College Research Institute 40: 149-153.
Braithwaite, C. J. R. 2016. The giant tortoise, Aldabrachelys, and its bearing on the biogeography and dispersal of terrestrial biota in the Western Indian Ocean. Palaeogeography, Palaeoclimatology, Palaeoecology 461: 449-459.
Brown, L. E., D. Moll, and E. S. Brown. 2018. Re-examination of the giant fossil tortoise Hesperotestudo from near the Illinois glacial-sangamon interglacial boundary in North America with commentary on zoogeography. Herpetological Journal 28: 73-86.
Cadena, E., and C. Jaramillo. 2015. Early to middle Miocene turtles from the northernmost tip of South America: Giant testudinids, chelids, and podocnemidids from the Castilletes Formation, Colombia. Ameghiana 52(2): 188-203.
Carbot-Chanona, G., et al. 2023. A new large tortoise from the early Oligocene (Arikareean NALMA) of Oaxaca, southern Mexico and its phylogenetic position within Pan-Testudinidae. Historical Biology 35(9): 1748-1761.
Chroust, M., T. Szczygielski, and A. H. Luján. 2025. Manouria morla sp. nov., the Ancient One: An early Miocene large tortoise from the swamps of Ahníkov, Czechia. Swiss Journal of Palaeontology 144: 63.
Corsini, J. A., et al. 2014. Reappraisal of Testudo antiqua (Testudines, Testudinidae) from the Miocene of Hohenhöwen, Germany. Journal of Paleontology 88(5): 948-966.
Dawson, M. R., et al. 1976. Paleogene terrestrial vertebrates: Northernmost occurrence, Ellesmere Island, Canada. Science 192: 781-782.
De la Fuente, M. S., G. G. Zacarías, and E. Vlachos. 2018. A review of the fossil record of South American turtles of the clade Testudinoidea. Bulletin of the Peabody Museum of Natural History 59(2): 269-286.
De Lapparent de Broin, F., et al. 2006. Eurotestudo, a new genus for the species Testudo hermanni Gmelin, 1789 (Chelonii, Testudinidae). Comptes Rendus Palevol 5: 803-811.
Eberle, J. J., and D. R. Greenwood. 2012. Life at the top of the greenhouse Eocene world—A review of the Eocene flora and vertebrate fauna from Canada’s High Arctic. GSA Bulletin 124(1/2): 3-23.
Eberle, J. J., et al. 2019. The first Tertiary fossils of mammals, turtles, and fish from Canada’s Yukon. American Museum Novitates (3943): 1-28.
Esker, D. A., S. L. Forman, and D. K. Butler. 2019. Reconstructing the mass and thermal ecology of North American Pleistocene tortoises. Paleobiology 45(2): 363-377.
Franz, R. 2014. The fossil record for North American tortoises. in: Rostal, D. C., E. D. McCoy, and H. R. Mushinsky (eds.). Biology and Conservation of North American Tortoises. Baltimore: Johns Hopkins University Press. Pp. 13-24.
Gerlach, J., et al. 2013. Giant tortoise distribution and abundance in the Seychelles Islands: Past, present, and future. Chelonian Conservation and Biology 12(1): 70-83.
Georgalis, G. L., L. Maculuso, and M. Delfino. 2021. A review of the fossil record of Afro-Arabian turtles of the clade Testudinoidea. Bulletin of the Peabody Museum of Natural History 62(1): 43-78.
Georgalis, G. L., et al. 2025. Testudinid turtle remains from the late Miocene palaeo-island of Gargano, Italy, and an overview of Mediterranean insular tortoises. Swiss Journal of Palaeontology 144(61): 1-24.
Gerlach, J., C. Muir, and M. D. Richmond. 2006. The first substantiated case of trans-oceanic tortoise dispersal. Journal of Natural History 40(41-43): 2403-2408.
Harrison, T. 2011. Tortoises (Chelonii, Testudinidae). in: Harrison, T. (ed.). Paleontology and Geology of Laetoli: Human Evolution in Context. Vol. 2: Fossil Hominins and the Associated Fauna. Vertebrate Paleobiology and Paleoanthropology DOI 10.1007/978-90-481-9962-4_17.
Hofmeyr, M. D., et al. 2017. Tortoise (Reptilia, Testudinidae) radiations in Southern Africa from the Eocene to the present. Zoologica Scripta 46(4): 389-400.
Ihlow, F., et al. 2024. Unexpected lack of genetic and morphological divergence in a widespread tortoise—Phylogeography of Indotestudo elongata. Salamandra 60(3): 183-194.
Itescu, Y., et al. 2014. Is the island rule general? Turtles disagree. Global Ecology and Biogeography 23(6): 689-700.
Jiménez-Hidalgo, E., et al. 2015. The first late Eocene continental faunal assemblage from tropical North America. Journal of South American Earth Sciences 57: 39-48.
Karl, H. V., U. Staesche, and A. Safi. 2021. New findings of Neogene tortoises Titanochelon kayadibiensis sp. nov. and Protestudo bessarabica (Riabinin, 1918) (Testudinidae) from the Miocene of western Turkey, with a review of fossil turtles of Turkey. SPC Journal of Environmental Sciences 3(1): 1-9.
Kehlmaier, C., et al. 2017. Tropical ancient DNA reveals relationships of the extinct Bahamian giant tortoise Chelonoidis alburyorum. Proceedings of the Royal Society B 284: 20162235.
Kehlmaier, C., et al. 2019. Ancient mitogenomics clarifies radiation of extinct Mascarene giant tortoises (Cylindraspis spp.). Scientific Reports 9: 17487.
Kehlmaier, C., et al. 2021. “Ancient DNA” reveals that the scientific name for an extinct tortoise from Cape Verde refers to an extant South American species. Scientific Reports 11: 17537.
Kehlmaier, C., et al. 2023. Ancient DNA elucidates the lost world of western Indian Ocean giant tortoises and reveals a new extinct species from Madagascar. Science Advances 9: eabq2574.
Kundu, S., et al. 2023. Mitochondrial DNA and distribution modelling evidenced the lost genetic diversity and wild-residence of star tortoise, Geochelone elegans (Testudines: Testudinidae) in India. Animals 13(1): 150.
Le, M., et al. 2006. A molecular phylogeny of tortoises (Testudines: Testudinidae) based on mitochondrial and nuclear genes. Molecular Phylogenetics and Evolution 40: 517-531.
Lichtig, A. J., and S. G. Lucas. 2016. Cretaceous nonmarine turtle biostratigraphy and evolutionary events. Cretaceous Period: Biotic Diversity and Biogeography. New Mexico Museum of Natural History and Science Bulletin 71: 185-194.
Lichtig, A. J., S. G. Lucas, and S. E. Jasinski. 2021. Complete specimens of the Eocene testudinoid turtles Echmatemys and Hadrianus and the North American origin of tortoises. Fossil Record 7. New Mexico Museum of Natural History and Science Bulletin 82: 161-176.
Loomis, F. B. 1927. A giant tortoise from Florida. American Journal of Science 13(77): 435-439.
Luján, À. H., et al. 2016. The Miocene tortoise Testudo catalaunica Bataller, 1926, and a revised phylogeny of extinct species of genus Testudo (Testudines: Testudinidae). Zoological Journal of the Linnean Society 178: 312-342.
Meylan, P. A. 2006. Introduction to the land tortoises: Family Testudinidae. Biology and Conservation of Florida Turtles. Chelonian Research Monographs 3: 348-349.
Meylan, P. A., and W. Sterrer. 2000. Hesperotestudo (Testudines: Testudinidae) from the Pleistocene of Bermuda, with comments on the phylogenetic position of the genus. Zoological Journal of the Linnean Society 128: 51-76.
Moll, D., and L. E. Brown. 2017. Reinterpretation of the climatic adaptation of giant fossil tortoises in North America. Herpetological Journal 27: 276-286.
Moll, D., L. E. Brown, and E. S. Brown. 2021. The evolutionary ecology of the African pancake tortoise Malacochersus tornieri (Siebenrock 1903): A review and synthesis based upon current knowledge. Tropical Natural History 21(1): 61-78.
Naksri, W., et al. 2019. Plio-Pleistocene giant tortoises from Tha Chang sandpits, Nakhon Ratchasima Province, Thailand. Annales de Paléontologie 105(4): 257-267.
Nussear, K. E., et al. 2007. Desert tortoise hibernation: Temperatures, timing, and environment. Copeia 2007(2): 378-386.
Olson, S. L., and P. A. Meylan. 2009. A second specimen of the Pleistocene Bermuda tortoise, Hesperotestudo bermudae Meylan and Sterrer. Chelonian Conservation and Biology 8(2): 211-212.
Palkovacs, E. P., J. Gerlach, and A. Caccone. 2002. The evolutionary origin of Indian Ocean tortoises (Dipsochelys). Molecular Phylogenetics and Evolution 24: 216-227.
Pérez-García, A., and E. Vlachos. 2014. New generic proposal for the European Neogene large testudinids (Cryptodira) and the first phylogenetic hypothesis for the medium and large representatives of the European Cenozoic record. Zoological Journal of the Linnean Society 172: 653-719.
Pérez-García, A., F. Ortega, and E. J. Fuentes. 2016. Taxonomy, systematics, and diversity of the European oldest testudinids. Zoological Journal of the Linnean Society 177: 648-675.
Pérez-García, A., E. Vlachos, and A. Arribas. 2017a. The last giant continental tortoise of Europe: A survivor in the Spanish Pleistocene site of Fonelas P-1. Palaeogeography, Palaeoclimatology, Palaeoecology 470: 30-39.
Pérez-García, A., E. Vlachos, and P. Mocho. 2017b. The westernmost records of extinct large European tortoises: The presence of Titanochelon (Testudinidae) in the Miocene of Portugal. Historical Biology 29(6): 854-861.
Pérez-García, A., E. Vlachos, and X. Murelaga. 2020. A large testudinid with African affinities in the Post-Messinian (Lower Pliocene) record of south-eastern Spain. Palaeontology 63(3): 497-512.
Pérez-García, A., et al. 2021. The most complete extinct species of Testudo (Testudines, Testudinidae) defined by several well-preserved skeletons from the late Miocene of Romania. Journal of Systematic Palaeontology 19(18): 1237-1270.
Sánchez-Marco, A., et al. 2025. Unraveling the strange case of the first Canarian Land Fauna (Lower Pliocene). Fossil Studies 3(13): 1-32.
Setiyabudi, E. 2009. An early Pleistocene giant tortoise (Reptilia; Testudines; Testudinidae) from the Bumiayu area, Central Java, Indonesia. Journal of Fossil Research 42(1): 1-11.
Ultsch, G. R. 2006. The ecology of overwintering among turtles: Where turtles overwinter and its consequences. Biological Reviews 81(3): 339-367.
Valenti, P., et al. 2022. The last of the large-sized tortoises of the Mediterranean islands. Zoological Journal of the Linnean Society 196(4): 1704-1717.
Vega-Pagán, K. A., et al. 2025. New remains of Titanochelon richardi (Testudines, Testudinidae) from the upper Miocene of the Vallès-Penedès Basin: Taxonomic and phylogenetic implications. Papers in Palaeontology 11(6): e70042.
Vlachos, E. 2018. A review of the fossil record of North American turtles in the clade Pan-Testudinoidea. Bulletin of the Peabody Museum of Natural History 59(1): 3-94.
Vlachos, E. 2019. On the nomenclature of the largest tortoise that ever lived: Megalochelys sivalensis Falconer & Cautley, 1837 vs. Colossochelys atlas Falconer & Cautley, 1844 (Reptilia, Testudinidae). Bulletin of Zoological Nomenclature 76: 162-164.
Vlachos, E. 2025. The affinities of the extinct giant tortoise “Testudo” punica from the Pliocene of Tunisia with the genus Titanochelon. Annales Paléontologie 111: 102754.
Vlachos, E., and M. Rabi. 2018. Total evidence analysis and body size evolution of extant and extinct tortoises (Testudines: Cryptodira: Pan-Testudinidae). Cladistics 34: 652-683.
Vlachos, E., M. S. de la Fuente, and J. Sterli. 2023. A new large-sized species of Chelonoidis (Testudinidae) without gibbosities from the middle Miocene of Aguada Escondida (NW Chubut, Patagonia, Argentina). The Anatomical Record 306: 1548-1557.
Zacarías, G. G., et al. 2013. Neuva especi de tortuga Terrestre gigante del género Chelonoidis Fitzinger, 1835 (Cryptodira: Testudinidae), del miembro inferior de la formación Toropí/Yupoí (Pleistoceno Tardío/Lujanense), Bella Vista, Corrientes, Argentina. Ameghiniana 50(3): 298-318.
