Table 4 - uploaded by Nicholas Czaplewski
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Measurements of Perognathus sp. B; anteroposterior length measured with crown walls held vertically.
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Citations
... Next to California in Arizona, Sigmodon minor is known from the Verde Formation at House Mountain localities 319 and 318. The age of locality 319 is inferred by the magnetic signature of the Nunivak subchron at 4.26 Ma, while the age of locality 318 is given by Cochiti at 3.98 Ma (Czaplewski 1987(Czaplewski , 1990, making this record one of the narrowest known for NA (Fig. 5) Sigmodon minor/minor and Sigmodon minor/medius in the Benson Fauna and Curtis Ranch Fauna, with a magnetostratigraphic age of 3.1 Ma in its maximum (Post Ranch locality), and a minimum range less than 1.71 Ma (a Glyptotherium locality during the Olduvai event). According to Lindsay (1990), the fauna of the Curstis Ranch, where the Glyptotherium locality was found, could correspond to the late Blancan and not to the early Irvingtonian, which is the basis in our adjustment of its temporal range (Fig. 5). ...
In this study, we present the first occurrence of Sigmodon minor in Mexico, collected in the Pliocene, early Blancan of the San Miguel de Allende Basin, Guanajuato. This record represents an early and rapid migration of these rodents from the Great Plains to lower latitudes, possibly in response to climatic fluctuations that occurred during the late Neogene and favored the grassland biome expansion. The fossils described in this manuscript are one of the most complete findings for this species, including well-preserved mandibles and maxillary elements, which were found in association with megafauna and have radiometric ages. The dental occlusal structure and evolutionary stages of the molars were compared in detail with other contemporary records in North America, in addition to palaeoecological inference based on body size, suggesting the predominance of an open grassland ecosystem but with a complex mosaic of niches of more wet conditions.
... Sand Draw, Nebraska $3.0-2.8 Ma (faunal correlation) Skinner and Hibbard (1972) and Czaplewski (1990) Miller and Carranza- Castañeda (1998), Cassiliano (1999) and Wang et al. (1999) Klein (1971) and Martin et al. (2000) Cuvieronius ( Meltzer and Mead (1985) and Morgan and Hulbert (1995) Repenning (1987) and Martin (1989) Synaptomys ( Morgan and Hulbert (1995) and Paulson (1961) Mammuthus ( Rogers et al. (1985) and Jass and Bell (2011) (Continued ) Early and Middle Pleistocene of North America Berta (1985), Meltzer and Mead (1985) and Hill and Easterla (2023) Ondatra zibethicus (muskrat) Kanopolis, Kansas $400 ka (faunal correlation) Extant Hibbard et al. (1978) and Martin (1996) Czaplewski et al. (1999) and Wilson and Hill (2020) Ba1, Hh1, and similar abbreviations refer to North American Land Mammal Age chronology and follow Tedford et al. (2004). ...
... Sigmodon holocuspis was described from House Mountain Loc. 318 in the Verde Formation of Arizona, in magnetically reversed sediments referred to the Gilbert chron, between 4.48-4.29 Ma (Czaplewski, 1990). For reasons noted in Marcolini and Martin (2008), we tentatively conclude that House Mountain Loc. ...
... Figure 4 presents a correlation of select lowest (oldest) and highest (youngest) Meade Basin rodent species records with the MPTS and with sections in the Verde and Panaca Formations of Arizona and Nevada, respectively. The Verde section was chosen because the MPTS there constrains the record of Sigmodon holocuspis between 4.29 and 4.38 Ma (Czaplewski 1990). The Panaca sequence records the early appearance of Ophiomys panacaensis relative to the Hemphillian-Blancan boundary (Lindsay et al. 2002). ...
The ubiquitous presence and rapid evolution of rodents lend this group to the development of a correlational scheme for United States Cenozoic continental fossil deposits, equivalent to the later Cenozoic section of European MN zones. Expanding on earlier work in the Meade Basin of southwestern Kansas and Florida, Pliocene and Pleistocene mammal assemblages from the northern and southern Great Plains and the eastern United States are correlated based on rodent biostratigraphy. Eleven rodent zones (RZs) are constructed for the last 5 million years based on a new database including all rodent species assemblages during the study period. In addition to the 11 refined RZs that aid in temporal sequencing of unknown rodent assemblages, three broader biozones are recognised, including an early period characterised by the Promimomys immigration event and Hemphillian holdovers, a longer, relatively warm Pliocene to early Pleistocene period dominated by primitive cricetids and archaic arvicolids, and a final zone spanning the last two million years defined by the immigration and radiation of hypselodont Microtus and large, dentally advanced species of the cotton rat, Sigmodon. Modern rodent communities are established in the later part of Biozone 3, between about 0.6–0.3 Ma.
... 6D), R. minor (Mou 2011, fig. 10-3), N. vaughani (Czaplewski 1990, fig. 9C), N. fossilis (Tomida 1987, fig. ...
... 11A) and will not be presented here. As an M3, measurements of this tooth are not particularly small, and are similar to those of the M3 of N. vaughani from the Verde Fm of Arizona (Czaplewski 1990). We are hesitant to name a new species based on the M3 or to refer the molar to a known species because the tooth is quite advanced in morphology, mimicking the M3 of a number of Pliocene through modern species of the genus Neotoma. ...
We evaluated the fossil record of extinct and extant woodrats, and generated a comprehensive phylogenetic hypothesis of woodrat origins and relationships based on these data. The galushamyinin cricetines are redefined and reclassified as a subtribe of the Neotomini, including Repomys, Miotomodon, Galushamys, Nelsonia, and a new extinct genus with two new species. The geographic distribution of Nelsonia, restricted to montane coniferous forests of western Mexico, suggests that this subtribe was mostly confined to western coniferous ecosystems or similar ecosystems at lower elevation during glacial advances. A second subtribe of the Neotomini includes a new archaic genus and species, Neotoma, Hodomys, and Xenomys. Lindsaymys, a possible neotominin from the late Clarendonian (late Miocene) of California, demonstrates an occlusal morphology consistent with ancestry for the Neotomini, but the presence of a fourth root on M1 is problematic and may preclude the known populations from filling that role. Molars identified as Neotoma sp. from the Hemphillian (latest Miocene or early Pliocene) Rancho el Ocote assemblage of Guanajuato, Mexico, may represent the earliest Xenomys. Extant Neotoma species with a bilobed m3 appear to have originated subsequent to about 2.0 Ma, whereas Hodomys alleni and Xenomys nelsoni likely originated earlier from one or more extinct ancestors with an S-shaped m3.
... The Sigmodontinae include at least eight tribes, including the Sigmodontini. The Sigmodontini is monotypic with Sigmodon, a genus known since the Blancan NALMA of the United States as the only extant genus (Czaplewski, 1990). The modern distribution of Sigmodon includes North, Central, and South America (Pardiñ as et al., 2002). ...
In the last decade, intensive paleontological fieldwork has been
carried out in Venezuela, resulting in many new fossil vertebrate localities being
found. Two sites of special significance are the fossil-rich tar pits of El Breal de
Orocual and Mene de Inciarte. El Breal de Orocual is located in Monagas State in the
northeast of Venezuela. Multiple individual pits have been identified and a fauna with
24 mammalian taxa was reported from an inactive tar pit (ORS16) with an estimated
Plio–Pleistocene age. However, the fossils so far collected and described from this
locality represent only a miniscule fraction of the total fossil material preserved there.
Three hundred meters west of the original site is a still active tar pit from which we
describe a new mammal assemblage named ORS20. This new mammal assemblage
(ORS20) is chronologically and taxonomically different from the previously reported
fauna (ORS16). Our taxonomic identifications of the mammals from ORS20 and
their known or inferred ages suggest a Late Pleistocene age for this fauna. The
multiple pits in the area of El Breal de Orocual contain a diverse fauna which
accumulated during distinctive episodes of deposition from the Late Pliocene/Early
Pleistocene (ORS16) until the Late Pleistocene (ORS20), indicting that surface
exposures of asphalt and the subsequent accumulation of vertebrate remains occurred
over a long period of time (about 2 My?), a situation that to date has not been
observed for other tar pits localities in North, Central, or South America. The
presence of the peccary Platygonus sp. and the armadillo Pachyarmatherium leiseyi,
in the Late Pleistocene of ORS20 represent the youngest appearances of these taxa in
the fossil record of South America.
... One fossil-based date was used to calibrate the BEAST analyses. The Early Blancan (4.4-4.2 million years ago, mya) woodrat fossil Paraneotoma provides a minimum age for the putative ancestor that gave rise to Hodomys alleni, a species placed at the root of the extant Neotoma species-radiation (Hibbard, 1967;Repenning and May, 1986;Czaplewski, 1990). To account for uncertainty in the fossil-based calibrations, the dates were modeled as log-normal distributions rather than point calibrations (Ho and Phillips, 2009). ...
Phylogenetic relationships of the Mexican endemic and endangered Nelson's woodrat, Neotoma nelsoni (Rodentia: Cricetidae), were examined using three mitochondrial genes (cytochrome-b, 12S ribosomal RNA, and 16S ribosomal RNA) for a total of 2,140 base pairs. Gene-sequences were analyzed using maximum likelihood and Bayesian models of phylogenetic inference. Independent analyses of the three gene-sequences converged on essentially identical gene trees, all showing N. nelsoni to be a sister lineage to N. leucodon from Durango, Mexico. Given the relatively low level of divergence of sequence of cytochrome-b between N. nelsoni and N. leucodon (3.3% using the Kimura two-parameter model, which is less than variation within N. leucodon) and the current absence of reliable diagnostic morphological characters to distinguish N. nelsoni from N. leucodon, N. nelsoni is recognized as a subspecies of N. leucodon. Based on molecular estimates of times of divergence, phyletic diversification in the species-group N. micropus (which includes N. leucodon nelsoni) began near the Middle Pleistocene and N. leucodon nelsoni diverged from other Mexican populations of N. leucodon during the Late Pleistocene. The repeated Pleistocenic cycles together with the final periods of volcanic activity in the eastern part of the Trans-Mexico Volcanic Belt may have played a major role in early differentiation in this lineage.
... In 1958, paleontologists from the Museum of Northern Arizona evaluated this fossil site and gave it the name "Elephant Hill" Seff ,1959, 1960). "Elephant Hill" has been the focus of other scientific and resource management attention, including: Twenter's 1962 survey of Verde Formation fossil sites; the 1994 Southwest Paleontological Society inventory of fossil tracks at MOCA; and the most recent investigation of the "Elephant Hill" tracksite, undertaken by Nicholas Czaplewski, a paleontologist with the Oklahoma Museum of Natural History (Czaplewski, 1990). The land that includes the "Elephant Hill" fossil locality was transferred to the National Park Service at MOCA in November 1978. ...
... The evolutionary stage of two other rodents from the Buckhorn LF, Ogmodontomys poaphagus and Repomys panacaensis, is also consistent with a late early Blancan age (between 4.0 and 3.0 Ma) for the Buckhorn Fauna. Broadly correlative early Blancan faunas from the southwestern United States are Arroyo de la Parida, Cuchillo Negro Creek, Mesa del Sol, Tonuco Mountain, and Truth or Consequences in the Rio Grande Valley of New Mexico (Morgan and Lucas 2003a; Morgan et al. 2011) and Benson, Clarkdale, Duncan, and Verde in Arizona (Czaplewski 1987Czaplewski , 1990 Tomida 1987; White and Morgan 2005). The Rexroad Fauna from Kansas, Beck Ranch in Texas, and Hagerman from Idaho are also similar in age (Bell et al. 2004). ...
The Santa Catalina Mountains are situated in southeastern Arizona within the Madrean Sky Island Chain, located in Pima and Pinal counties. The study area is 124,812 ha (308,416 ac, or 481.6 mi2), with an elevation gradient from 762 m (2,500 ft) to 2,197 m (9,157 ft). Although only the 5th tallest range in southern Arizona, the Santa Catalinas possess the greatest currently known vascular plant diversity within the area. The flora contains 1,391 species (1,436 species and infraspecific taxa) of vascular plants, with Madrean, Sonoran, Chihuahuan, and Rocky Mountain affinities. In contrast, the Gila National Forest area in southwestern New Mexico, with a similarly large elevation and vegetation gradient but an area roughly 10 times larger (1.4 million ha, or 3.5 million ac) contains about 1,650 species (documented in gilaflora.com and SEINet), or roughly only 10% more species. This presentation compares the floras of these two sister mountainous regions, highlighting key floristic similarities, contrasts and threats.
... Whether the Cuchillo Negro Creek dentary is indicative of a small undescribed species of Bassariscus, possibly also known from Beck Ranch, or perhaps a juvenile individual cannot be determined based on the available material. (Hibbard, 1952;Dalquest, 1978;Anderson, 1984;Baskin, 1998a;Murray, 2006a), and Bassariscus sp. was identified from the early Blancan Verde LF in Arizona (Czaplewski, 1990). Harris (1993) reported the living species B. astutus from about ten late Pleistocene cave deposits in southern New Mexico. ...
... The similarity in age of the Truth or Consequences and the Buckhorn LFs is based primarily on comparisons of these faunas with other early Blancan faunas outside of New Mexico. Both faunas share small mammals with the early Blancan Verde LF from Arizona (Czaplewski, 1987a(Czaplewski, , 1990. Ogmodontomys poaphagus occurs in both Buckhorn and Verde, whereas Sigmodon medius and Jacobsomys are shared by Truth or Consequences and Verde. ...
