Shamblin et al. (2014, PLoS One 9:e85956), using samples from 42 nesting rookeries, identified 59 different mitochondrial haplotypes. They made no taxonomic recommendations.

Okamoto and Kamezaki (2014, Current Herpetology 33: 46–56) demonstrated the presence of two phenotypes and argued that one form represented Chelonia agassizii. Rhodin et al. (2021, Chelonian Research Monographs : 1–472) considered C. agassizii to be a synonym of C. mydas. Naro-Maciel et al. (2014, Journal of Experimental Marine Biology and Ecology 461: 306–316) revealed a barrier to dispersal between the northern and southern Atlantic populations but made no taxonomic recommendations.

Bowen and Karl (2007, Molecular Ecology 16: 4886–4907) reviewed population genetics and phylogeography of marine turtles and while they noted mtDNA divergence between Indo-Pacific and Atlantic Eretmochelys imbricata, they recognized not taxa below the species level. Gaos et al. (2016, Ecology and Evolution 6: 1251–1264) suggested that Eastern Pacific E. imbricata are more closely related to those from the Indo-Pacific than those in the Atlantic. However, they made no taxonomic recommendations affecting the currently recognized subspecies. Rhodin et al. (2021, Chelonian Research Monographs : 1–472) recognized no subspecies, treating E. i. bissa (Rüppell, 1835) as a synonym of E. imbricata.

While not explicitly discussed in the 8th Edition (2017) Flores-Villa et al. (2016, Chelonian Conservation and Biology 15: 57–162) reported that the source of the name Chelonia olivacea (now Lepidochelys olivacea), before credited to (Eschscholtz, 1829, Zoologischer Atas, Enthaltend Abbildungen und Beschreibungen neuer Thierarten, während des Flottcapitains v. Kotzebue zweiter Reise um die Welt, auf der russisch-kaiserlichen Kriegsschlupp Predpriaetië in den Jahren 1823–1826. Bei G. Reimer, Berlin, Germany) (published after May 1829), was actually first published in January of that year by Eschscholtz (1829, Quatember 1: 10–18).

The standardized English name changed from Snapping Turtle to Common Snapping Turtle to differentiate it from the Alligator Snapping Turtles (Macrochelys spp.). The use of the word Common in the name of this taxon was removed from the previous version of this list by Iverson et al. (p. 83 in Crother, 2017) because it "might be misinterpreted as referring to the abundance of the species." However, its use is in reference to the taxon as a well-known, widely distributed turtle. Common is used similarly in the English names of at least 15 snakes and lizards. Common Snapping Turtle has a long history as an English name for this taxon (Jordan, 1876, Manual of the Vertebrates of the Northern United States: Including the District East of the Mississippi River, and North of North Carolina and Tennessee, Exclusive of Marine Species). The name Common Snapping Turtle was listed as an alternative English name for this taxon by Rhodin et al. (2021, Chelonian Research Monographs : 1–472). "North American Snapping Turtle" (Rhodin [op. cit.]; Hansen and Shedd [2025, California Amphibians and Reptiles. Princeton University Press]) was considered, however there are other species of Chelydra that occur in North America (extralimital).

The standard English name is changed from Alligator Snapping Turtle to differentiate it from the Suwannee Alligator Snapping Turtle. Western Alligator Snapping Turtle is in use, e.g., Munscher et al. (2021, Herpetology Notes 14: 985–994) and Rhodin et al. (2021 Chelonian Research Monographs : 1–472).

Molfetti et al. (2013, PLoS One 8:e58061) and Dutton et al. (2013, Conservation Genetics 14: 625–636) demonstrated genetic structure within Dermochelys coriacea in the Atlantic Ocean. They made no taxonomic recommendations.

Jensen et al. (2014, Conservation Genetics 15: 261–274) examined genetic variation among populations of C. picta. They found local population clusters that supported the continued recognition of C. dorsalis and C. picta but made no taxonomic recommendations. Jensen et al. (2015, Journal of Herpetology 49: 314–324) further examined the range-wide genetic variation of C. picta and found no support for the currently recognized subspecies. Reid et al. (2018, Heredity 122: 441–457) found genetic and morphological variability throughout its range. However, they did not reject subspecies outright. Rhodin et al. (2021, Chelonian Research Monographs : 1–472) continue to recognize three subspecies of C. picta.

Davy and Murphy (2014, Canadian Journal of Zoology 92: 149–162) identified significant genetic structure within Canadian populations of C. guttata. They made no taxonomic recommendations.

Distinct genetic units have been identified in Canada (Davy et al., 2014, Canadian Journal of Zoology 92: 149–162), the midwestern USA (Sethuraman et al., 2014, Conservation Genetics 15: 61–73), and New York (McCluskey et al., 2016, Journal of Herpetology 50: 7–76). None of these studies made any taxonomic recommendations. Rhodin et al. (2021, Chelonian Research Monographs : 1–472) recommended additional range-wide studies of this genetically diverse taxon.

Ward et al. (2013, Copeia 2013: 723–728) found divergence in microsatellites, life history, morphology, and coloration between populations in the Upper Guadalupe River compared to those in the Middle Guadalupe and San Marcos Rivers. No taxonomic recommendations were made.

Ennen et al. (2014, Biological Journal of the Linnean Society 111: 810–822) determined that there is not sufficient evidence for the recognition of G. n. delticola. Rhodin et al. (2021, Chelonian Research Monographs 8: 1–472) did not recognize the subspecies G. n. delticola and G. n. nigrinoda.

Lindeman et al. (2015, Herpetological Review 46: 179–185) demonstrated that G. pseudogeographica from the Calcasieu River drainage in southwestern Louisiana differs from other populations in having a unique eye color and variable chin pattern. They made no taxonomic recommendations.

Hart et al. (2014, Conservation Genetics 15: 593–603) and Drabeck et al. (2014, Journal of Herpetology 48: 125–136) examined genetic geographic variation across the range of M. terrapin. They both questioned if the current subspecies designations were warranted; however, they made no explicit taxonomic recommendations. Rhodin et al. (2021, Chelonian Research Monographs : 1–472) retained the existing subspecies pending additional studies with more complete geographic sampling.
Rhodin et al. (op. cit.) use "Diamondback" in the standardized English name for M. terrapin and all of its subspecies. "Diamondback Terrapin" is used by the IUCN Red List and most conservation organizations (Anders Rhodin, , personal communication).

Rhodin et al. (2021, Chelonian Research Monographs 8: 1–472) recognized two subspecies, Pseudemys c. concinna and P. c. suwanniensis, and treated P. floridana as a distinct species.

Elevated to specific status by Rhodin et al. (2021, Chelonian Research Monographs 8: 1–472).

The carolina group of North American Box Turtles has received considerable recent taxonomic attention, with some improved resolution. Vitek (2018, PLoS One 13:e0193437) examined the morphometrics in the groups, including fossil forms and found considerable overlap among Terrapene carolina (including T. c. major), T. bauri, and T. triunguis such that differences among the taxa were not diagnosable. Martin et al. (2020, Molecular Ecology 29: 4186–4202) and Martin et al. (2021, Molecular Ecology Resources 21: 2801–2817) bolstered their prior work by further refining phylogenetic relationships at taxonomic boundaries. Rhodin (2021, Chelonian Research Monographs 8: 1–472) recognized T. baurii, T. mexicana (extralimital), T. triunguis, and T. yucatana (extralimital) as separate species and retained T. c. major as a subspecies.

Martin et al. (2013, Molecular Phylogenetics and Evolution 68: 119–134) found no support for a distinction between subspecies ornata and luteola and recommended their synonymy. Crother (2017, Herpetological Circulars (43): 102) cautiously retained both subspecies pending further geographic and molecular study. Rhodin et al. (2021, Chelonian Research Monographs 8: 1–472) synonymized luteola in ornata; however, they state that more complete genetic sampling may revise this decision.

Martin et al. (2013, Molecular Phylogenetics and Evolution 68: 119–134) found support for a western (including triunguis, mexicana, and yucatana) and an eastern group (carolina, baurii, and major, plus coahuila) within T. carolina. They elevated the former to species status (T. mexicana, the oldest name) with three subspecies (including triunguis). However, Fritz and Havas (2014, Zootaxa (3835): 295–298) argued against the recognition of mexicana (including triunguis) as a separate species because of demonstrated genetic introgression between triunguis and carolina. Nevertheless, because of documented interspecific hybridization between many other closely related turtle species, Martin et al. (2014, Zootaxa (3835): 292–294) reaffirmed and bolstered (2020, Molecular Ecology 29: 4186–4202; 2021, Molecular Ecology Resources 21: 2801–2817) their support for recognizing mexicana (including triunguis) and carolina as separate species. Rhodin (2021, Chelonian Research Monographs 8: 1–472) tentatively recognized the Three-toed Box Turtle as a distinct species (Terrapene triunguis) (see taxonomic comments on p. 368; account p. 187), rather than a subspecies of either T. carolina or T. mexicana.

Forstner et al. (2014, Proceedings of the Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region) and Parham et al. (2015, Proceedings of the California Academy of Science 62: 359–367) elevated T. g. hartwegi (extralimital) to species status based on genetic differences between it and T. g. gaigeae. Parham et al. (2015, op. cit.) also demonstrated the close relatedness of T. hartwegi to T. taylori and T. venustus. Rhodin et al. (2021, Chelonian Research Monographs 8: 1–472) accepted this arrangement.

McCord (2016, Historical Biology 28: 310–315) recommended restricting Kinosternon arizonense to fossil material and resurrecting the name K. stejnegeri for extant populations. Joyce and Bourque (2016, Bulletin of the Peabody Museum of Natural History 57: 57–95) accepted this arrangement. Rhodin et al. (2021, Chelonian Research Monographs 8: 1–472) list K. stejnegeri as the extant species, with K. arizonense considered a separate extinct species from the Pliocene-Pleistocene.

(Lacépède, 1788) was listed as the authority in previous editions of this list. That work was suppressed for nomenclatural purposes by ICZN (2005, Bulletin of Zoological Nomenclature 62: 55) as published in a rejected and invalid non-binomial work and replaced with (Bonnaterre, 1789). Rhodin et al. (2021, Chelonian Research Monographs 8: 1–472 [382]) agreed.

'(Gray, 1855)' [Catalogue of shield reptiles in the collection of the British Museum. Part I. Testudinata (Tortoises). Taylor and Francis, London, England] was listed as the authority in previous editions of this list. That publication didn't appear until 8 March 1856 (Webb, 1995, Chelonian Conservation and Biology 1: 322–32). Gray (1856, Proceedings of the Zoological Society of London 1855: 197–202) was published on 5 February 1856 (Webb, op. cit.), and therefore has priority.
Based on species-tree and demographic modeling, Scott et al. (2018, Molecular Phylogenetics and Evolution 120: 1–15) found strong support for the recognition of S. carinatus as has been previously defined.

Scott and Rissler (2015, Biological Conservation 192: 294–303) reported a decline in the historical range of S. depressus and unidirectional mtDNA introgression from S. peltifer. Rhodin et al. (2021, Chelonian Research Monographs : 1–472) noted that this hybridization is changing the morphology of S. depressus and threatens its continued distinction.

Named by Scott et al. (2018, Molecular Phylogenetics and Evolution 120: 1–15) for its historic recognition as a hypothetical "intermediate" form between S. peltifer and S. minor (e.g., Ernst et al., 1988, The American Midland Naturalist 120: 282–288) and supported by Rhodin et al. (2021, Chelonian Research Monographs 8: 1–472).

Rhodin et al. (2021, Chelonian Research Monographs 8: 1–472) elevated S. m. peltifer based on Scott et al. (2018, Molecular Phylogenetics and Evolution 120: 1–15) and recognized no subspecies within S. minor.

Bourque (2016) suggested the elevation of this taxon to species status based on the work of Iverson et al. (2013, Molecular Phylogenetics and Evolution 69: 929–939) and Bourque and Schubert (2015, Journal of Vertebrate Paleontology 35(doi: 10.1080/02724634.2014.885441)). Additionally, Guyer (2015, Turtles of Alabama. University of Alabama Press) recommended elevating this taxon based on the work of Walker et al. (1995, Molecular Ecology 4: 365–373). Elevated in Rhodin et al. (2021, Chelonian Research Monographs 8: 1–472) based on Scott et al. (2018, Molecular Phylogenetics and Evolution 120: 1–15).

Crother (2017, Herpetological Circulars (43): 102) changed the name "Mojave Desert Tortoise" to "Mohave Desert Tortoise to be consistent with the standard English names of several other taxa while recognizing that both names are acceptable (detailed on page 64). With respect to this turtle, "Mojave" is in the greatest usage (e.g., Rhodin et al. (2021, Chelonian Research Monographs : 1–472)) and the standard English name Mojave Desert Tortoise is retained.

Newly listed taxon. The extant range is confined to the Bolson de Mapimi basin of Chihuahua, Coahuila, and Durango, Mexico. However, before the presence of humans, it ranged as far north as New Mexico, USA, and south as Aguascalientes, Mexico (Affenberg and Franz, 1978, Catalogue of American Amphibians and Reptiles (214): 1–2; Morafka, 1982,. North American tortoises: Conservation and ecology. Wildlife Research Report 12. United States Department of the Interior, Fish and Wildlife Service, Washington, D.C.). The Bolson Tortoise underwent a severe and rapid human-induced extirpation from most of its range late in the Pleistocene (Morafka, 1988, Annals of Carnegie Museum 57: 47–72). In 1979, the Bolson Tortoise was listed as endangered under the United States Endangered Species Act (USFWS, 2006, Federal Register 44: 23062–23064). Sixteen adult tortoises from the Mapimi Biosphere Reserve (Mexico) were translocated to an enclosed captive-breeding program on the Appleton Research Ranch in Elgin, Arizona, between 1971 and 1976 (Appleton, 1978, Proceedings of the Desert Tortoise Council Symposium. Desert Tortoise Council, Las Vegas, Nevada). In September 2006, 37 tortoises were moved from the Appleton Research Ranch to three locations in New Mexico (Zylstra, 2006, Sonoran Herpetologist 20: 50–54).