Woodburne, M.O.; Cione, A.L.; and Tonni, E.P., 2006, Central American provincialism and the 73 Great American Biotic Interchange, in Carranza-Castañeda, Óscar, and Lindsay, E.H., eds., Ad- vances in late Tertiary vertebrate paleontology in Mexico and the Great American Biotic In- terchange: Universidad Nacional Autónoma de México, Instituto de Geología and Centro de Geociencias, Publicación Especial 4, p. 73–101.

Central American provincialism and the Great American Biotic Interchange

Michael O. Woodburne1,* Alberto L. Cione2,**, and Eduardo P. Tonni2,***

ABSTRACT

The age and phyletic context of mammals that dispersed between North and South America during the past 9 m.y. is summarized. The presence of a Central American province of cladogenesis and faunal differentiation is explored. One apparent aspect of such a province is to delay dispersals of some taxa northward from Mexico into the continental United States, largely during the Blancan. Examples are recognized among the various xenar- thrans, and cervid artiodactyls. Whereas the concept of a Central American province has been mentioned in past investigations it is upgraded here. Paratoceras (protoceratid artio- dactyl) and rhynchotheriine proboscideans provide perhaps the most compelling examples of Central American cladogenesis (late Arikareean to early Barstovian and Hemphillian to Rancholabrean, respectively), but this category includes Hemphillian sigmodontine rodents, and perhaps a variety of carnivores and ungulates from Honduras in the medial Miocene, as well as peccaries and equids from Mexico. For South America, Mexican canids and hy- drochoerid rodents may have had an earlier development in Mexico. Remarkably, the first South American immigrants to Mexico (after the Miocene heralds; the xenarthrans Plaina and Glossotherium) apparently dispersed northward at the same time as the first Holarctic taxa dispersed to South America (sigmodontine rodents and the tayassuid artiodactyls). The main (Phase One) Great American Biotic Interchange (GABI) bipolar episode transpired from about 2.7–1.8 Ma, with laggards lasting until about 1.0 Ma. A later phase occurred from about 0.8 Ma to virtually modern times and resulted in mainly southern enrichment.

Key words: Great American Biotic Interchange, vertebrate paleontology, dispersal, provinciality.

RESUMEN

Se presenta en forma sucinta la edad y el contexto filético de los mamíferos que se dispersaron entre América del Norte y del Sur durante los pasados nueve millones de años. Se explora la posible presencia de una provincia Centroamericana de cladogénesis y diferenciación faunística. Un aspecto relevante de tal provincia es el retardo en la dispersión de algunos taxones hacia el norte, de México a los Estados Unidos de América, principalmente durante el Blancano; como ejemplos de ello se tiene a los diversos xenartros y los artiodáctilos cérvidos. El concepto de una provincia Centroamericana de tales características ya ha sido tratado en investigaciones pasadas; en el presente estudio, dicho concepto es afinado.

1Department of Geology, Museum of Northern Arizona, 3101 N. Fort Valley Rd., Flagstaff, AZ 86001 *E-mail address: [email protected] 2Departamento Científico Paleontología Vertebrados, Museo de La Plata, 1900 La Plata, Argentina **E-mail address: [email protected] ***E-mail address: [email protected]

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Quizá los dos ejemplos más convincentes de cladogénesis en América Central sean el de Paratoceras (artiodáctilo protocerátido del Arikareeano tardío al Barstoviano temprano) y el de los proboscídeos ryncotherinos (Henfiliano a Rancholabreano); adicionalmente, esta categoría incluye roedores sigmodontinos del Henfiliano y, quizá, una diversidad de carnívoros y ungulados de Honduras en el Mioceno medio, así como de pecaríes y équidos de México. Para América del Sur, los cánidos y los roedores hidrocoéridos pueden haber tenido un desarrollo más temprano en México. Es notorio que los primeros inmigrantes sudamericanos a México (después de los precursores del Mioceno: los xenartros Plaina y Glossotherium) se dispersaron hacia el norte, a la vez que los primeros taxones holárticos se dispersaron a Sudamérica (roedores sigmodontinos y artiodáctilos tayasuidos). El episodio bipolar principal (Fase Uno) del Gran Intercambio Biótico Americano (GABI, por sus siglas en inglés) transcurrió durante el intervalo 2.7–1.8 Ma, con rezago que subsistió hasta hace cerca de 1.0 Ma. Una fase posterior ocurrió hace aproximadamente 0.8 Ma, en tiempos virtualmente modernos, y tuvo como resultado un enriquecimiento principalmente meridional.

Key words: Gran Intercambio Biótico Americano, paleontología de vertebrados, dispersión, provincialismo.

INTRODUCTION (procyonids, gomphotheres) reached South America by 7–9 Ma (Table 1) well in advance of 2.7–2.5 Ma Studies of land mammal dispersal between North and (e.g., Campbell et al., 2000; Carranza-Castañeda and South America usually focus on the Great American Miller, 2004; Morgan, 2005), at least in part coinci- Interchange or Great American Biotic Interchange dent with the earliest immigration of ground sloths (GABI) which began about 2.7 Ma and lasted into vir- (Pliometanastes, Thinobadistes) to North America (ca. tually modern times. The dispersal episodes are popu- 8–9 Ma; Hirschfeld, 1981; Webb 1985; Morgan, 2005). lated by suites of animals that display taxonomic facies After procyonids, the first North American taxa are which differ not only geographically, but temporally. sigmodontine rodents in Montehermosan beds perhaps The GABI events are summarized here before moving at 5–6 Ma. For many years, a classical view that pre- on to a discussion of faunal provinciality, evolution, vailed among workers maintained that representatives and dispersal with which participants in the GABI must of two families of North American origin occurred in have been associated. Chapadmalalan beds of southern South America and The Great American Biotic Interchange reflects eight in post Chapadmalalan-pre-Ensenadan beds (the the end of the Cenozoic isolation of South America with “Uquían”; see Marshall et al., 1984; Webb, 1985). respect to the land mammals and birds of that region in However, a new emphasis on biostratigraphical stud- contrast to those of Central and North America (Marshall ies demonstrated that the first occurrences of different et al., 1979). This episode witnessed land mammal dis- species of North American families in the south are persals across the newly established Isthmus of Panama, distributed in beds that encompass more than 4 mil- and resulted in faunas of both areas being enriched by lion years (one in the Chapadmalalan, one in the lower taxa from the other. In South America, North American Marplatan, two in the middle Marplatan, one in the up- mammalian immigrants included tayassuids, rodents, per Marplatan and four in the Ensenadan [Tonni et al., canids, gomphotheriids, camelids, cervids, felids, and 1992; Cione and Tonni, 1995, 2001, 2005]). In addi- ursids, although not all at the same time. For North tion there are other species of five families of North America, newcomers were largely edentates, but also American origin in very recent beds or with no fossil included rodents and marsupials. record at all (Webb, 1985; Cione and Tonni, 1995). It is well known that these dispersals took place More recently, Carranza-Castañeda and Miller at different times in the past 9 m.y. and that certain taxa (2004) and Flynn and others (2005) showed that

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Neotropical immigrants to North America, Glossotherium TECTONIC/GEOLOGIC BACKGROUND and Plaina, were present in the vicinity of Guanajuato, central Mexico, by 4.6–4.8 Ma, and that Glossotherium Coates and others (2004) indicate that the Panamanian reached the USA somewhat later (3.0 Ma, Table 1), but region was progressively uplifted from about 12 to at still prior to the beginning of the late Blancan and the least 4.8 Ma, with concomitant disruption of formerly GABI. According to Tonni and others (1992) and Cione confluent marine depositional environments and fau- and Tonni (1995), Plaina occurs between 3.3 and 5.0 nas, and reflected in the overland dispersals across the Ma in the Chapadmalalan SALMA (South American Panamanian region at 8–9 Ma. Continued tectonic ac- Land Mammal Age) of Argentina. Whether this reflects tivity raised the region still more, coincident with the an evolutionary role for Central America and south- mammalian dispersals at ca. 4.8 Ma and subsequent- ward dispersal cannot be solved at present (and the ge- ly (GABI), after a brief episode of eustatic sea level nus seemingly does not occur in the USA in any case). rise that breached the peninsula at 6–7 Ma. According Megalonyx also is known from the early Blancan sites at to Haug and Tiedemann (1998) and Haug and others Guanajuato but rather than being designated as an immi- (2001) the Panamanian isthmus was a firm barrier to grant at Guanajuato by Carranza-Castañeda and Miller Caribbean-Pacific circulation from 4.7–4.2 Ma, and (2004) and Flynn and others (2005), Megalonyx is con- Hoernle and others (2002) show how the Caribbean sidered as an endemic North American descendant of plate presented an overland dispersal route in the Late Pliometanastes (e.g., Morgan, 2005). The reason(s) for Cretaceous-Paleocene as well as in the Pliocene. the delayed dispersal of these and other taxa (Neochoerus, For central Mexico, the Transmexican Volcanic Glyptotherium) from central Mexico to the USA remain Belt (Figure 1) experienced a significant episode of cryptic, as discussed further below. bimodal volcanism in the Hemingfordian-Barstovian From the southern South American perspective, interval (Carranza-Castañeda and Miller, 2004) but the a number of workers in the past decade have made effects of this activity were followed in the Hemphillian considerable advances relative to the composition and and Blancan, at least, by erosion and basin filling with timing of the units that contain North American immi- intermittent deposition of air-fall tuffs (e.g., Flynn et grants. Chief among these are Tonni and others (1992), al., 2005). There seems to be no obvious or conve- Cione and Tonni (1995, 2001, 2005), Cione and others nient geological barrier between central Mexico and (2001), and references cited therein. Other students of the United States to account for the temporal disjunc- the GABI also have made significant advances in syn- tion of dispersals between those places. The Basin and thesis and interpretation (e.g., Marshall and Sempere, Range Province, that extends from Arizona and New 1993; Webb and Rancy, 1996; Carranza-Castañeda Mexico into northern Mexico (Henry, 1989; Kowallis and Miller, 2004; Morgan, 2005). The following is de- et al., 1998) likewise had largely ceased activity by the signed to bring these data and inferences into a general Hemphillian and in any case also provides no boundary synthesis and to offer suggestions as to implications setting. for the continuity of dispersal between the Americas. The dispersal history is summarized in Table 1 which ECOLOGIC FACTORS shows the taxa in North and South America that per- tain to land mammal families that participated in the Webb and Rancy (1996) summarize the ecologic con- faunal exchanges between them. In some instances the text of Central America and adjacent areas. Prior to and South American record includes notation regarding the coeval with the GABI, the region supported a general North American record of certain genera. Not all South savanna setting with relatively open conditions. This American taxa are immigrants, but are included to pro- also continued during the interval of glacial cooling vide an impression of endemic radiations. Appendix I (from about 2.5 Ma) with concomitant lowering of sea provides comments on the timing and contextual as- level (Figure 2). Recent research confirms that the on- pects of the taxa involved, including endemic genera. set of significant glaciation in the Northern Hemisphere

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TMVB

Scale

Figure 1. Map of Mexico-Central America showing fossil localities discussed in the text. A = Aguascalientes; G = Guanajuato; H = Honduras; M = Mixson’s Bone Bed, Florida; P = Panama; O = Oaxaca and Chiapas; Y = Yepómera. TMVB = Transmexican Volcanic Belt. began at 2.7 Ma (Haug et al., 2005). This climatic event conditions in the Andes played a part in facilitating the must have had a remarkable influence on the vegetation main GABI dispersals into North America of temper- as well as opening up areas of coastal habitat not previ- ate South American taxa on one hand, and on the other ously available, and surely favored the dispersals in the promoted provincialism in the later Pleistocene and Pliocene that formerly were not so facilitated. Recent (see also Cione et al., 2003). In South America The first and main episode of interchange the mid- to late Pleistocene record shows diversification transpired from late Blancan (ca. 2.7 Ma) into the of groups having arrived earlier from North America, Irvingtonian (ca. 1.4 Ma), and was populated mostly with remarkably wide distribution. Clusters of ende- by savanna-dwelling forms living under perhaps cli- mism are recorded by the north temperate mastodon, matically somewhat cooler conditions than had ob- mammoth, Bison and Camelops restricted to Central tained in the Hemphillian. This is also reflected in the America. A component of south temperate forms also immigrants largely being drawn from ancient South shows regional endemism (pampas deer, pampean American stocks and is demonstrated in the diversity of glyptodonts and armadillos) in southeastern Brazil. such taxa appearing in Central America: descendants of Oligocene rodents and primates, and older stocks such DISPERSAL SCENARIO as marsupials and xenarthrans (armadillos, anteaters, and sloths). Pre-GABI, Late Miocene and Early Pliocene By about the beginning of the middle Pleistocene (ca. 0.8–0.6 Ma), rainforest conditions extended from A summary of recent literature results in the follow- South America to Central America, and contributed to ing reconstruction of dispersal participants and tim- the diminished dispersals from that time onward (Figure ing (Table 1; Appendix I). As indicated above, meg- 2). Webb and Rancy (1996) point out that elevational alonychid and mylodontid edentates (Pliometanastes, partitioning of subtropical versus more savanna-like Thinobadistes) apparently swam across the Caribbean

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Figure 2. Chronology of North and South American immigration episodes. South American record is after Cione and Tonni (2001). North American episodes are as in the text. For North American dispersals taxa in () are younger USA occurrences subsequent to an earlier record in Mexico. GABI = Great American Biotic Interchange. Relative chronological sequence in the late Blancan record is comparable to ages in Table 1. Arrows show H (high) and L (low) sea levels, after Gradstein and others (2004). * = immigrant from USA.

Carranza-Castañeda, Óscar, and Lindsay, E.H. eds., Advances in late Tertiary vertebrate paleontology in Mexico 2006 78 Woodburne, Cione and Tonni Table 1. First occurrences of taxa involved in the Great American Biotic Interchange. 1. First occurrences of taxa involved in the Great Table

Universidad Nacional Autónoma de México, Instituto de Geología and Centro de Geociencias Publicación Especial 4 Central American provincialism and the Great American Biotic Interchange 79 about 9 Ma, possibly coincident with the Peruvian (1986), Abelmoschomys, from the latest Clarendonian gomphothere Amahuacatherium. Gutiérrez and others Love Bone Bed of Florida, is an early sigmodontine. (2005), and Alberdi and others (2004) express reserva- Antecalomys (Korth, 1998) is a contemporaneous tions about the age and taxonomy of this genus. López form from Nebraska. Baskin (1978) described the late and others (2001) consider proboscideans to first appear Hemphillian Bensonomys from Arizona and placed it as in the Sanandresian of Argentina, or at about 2 Ma. a subgenus of the living South American genus Calomys A procyonid carnivore followed at about 7 Ma (but see Pardiñas et al., 2002, for a different opin- (Cione and Tonni, 2001; Baskin, 1989), resulting in the ion). Bensonomys also occurs in the late Hemphillian endemic genus Cyonasua. The North American xenar- Yepómera Fauna, northern Mexico (Lindsay and thran Megalonyx apparently evolved endemically from Jacobs, 1985), and the Rancho El Ocote Fauna of Pliometanastes by about 7 Ma, so its presence in cen- Guanajuato, central Mexico (Carranza-Castañeda and tral Mexico at 4.7 Ma (Carranza-Castañeda and Miller, Walton, 1992). Other North American sigmodontines 2004; Flynn et al., 2005) has no bearing on the early include Repomys (late Hemphillian to late Blancan; development of the Panamanian isthmus (also Morgan, Tedford et al., 1987) and Jacobsomys (early Blancan 2005). Verde Fauna, Arizona; Czaplewski, 1987). The central Mexican record of Glossotherium and The Chapadmalalan tayassuid Platygonus is an Plaina (Carranza-Castañeda and Miller, 2004; Flynn et additional immigrant at about 4 Ma in association with al., 2005) at about 4.8 Ma appears to reflect geologi- the endemic genus Argyrohyus. Wright (1998) indicates cal evidence (above) regarding the establishment of the that this peccary group occurs in late Hemphillian fau- Isthmus of Panama. In that the earliest record of Plaina nas of North America. in South America appears to be of Chapadmalalan age At about 3.5 Ma, Capromeryx apparently entered (within about 3.3–5.0 Ma), the Mexican occurrence the USA from a slightly earlier presence in Mexico, may be the oldest for that genus. and whereas this has nothing to do directly with the Baskin (1986) summarizes evidence in favor of GABI, it does address the question of dispersal barriers the Hemphillian origin and diversification of sigmo- between the continental United States and districts to dontine rodents in North America prior to their diver- the south (see below). In any case, another precursor sification in Mexico in the late Hemphillian (Carranza- of the GABI, Neochoerus, is found in central Mexico Castañeda and Walton, 1992) and dispersal to South about then (3.3 Ma) also attesting to the likely presence America in the early Blancan. As revised here, these of the Panamanian isthmus at that time. rodents arrived in the late Montehermosan, consid- If it had a southern source, the dispersal of ered (Pardiñas and Tonni, 1998) as about 5.8 Ma Neochoerus to Mexico apparently transpired at about (Figure 2), and about contemporaneous with their re- 3.3 Ma, coeval with the latest Chapadmalalan (Figure cord in Mexico. Endemic members of this immigrant 2). The question of source stems from the observation group (Auliscomys, Necromys) are sparse but present that the earliest occurrence of Neochoerus in South in the type Montehermosan in southern Buenos Aires America apparently is in the Ensenadan, at levels province (Table 1). Diego Verzi (2006, personal com- younger than about 2.0 Ma (Table 1). munication to Cione) considers that an indeterminate The early Marplatan saw the immigration to sigmodontine from possibly coeval deposits in north- South America of camels (Lama) at about 3.0 Ma. ern La Pampa Province (Argentina) is more primitive Glossotherium and the other taxa discussed next have than Auliscomys or Necromys (see also Montalvo et al., their earliest or an old occurrence in Florida, but many 2000). Sigmodontine rodents are well represented (and also are found in other sites in the continental USA phyletically diverse; Table 1) by the Chapadmalalan at (Morgan, 2005). At about 3.0 Ma, Glossotherium is ca. 4.0 Ma. Their presence in South America is con- found in the USA subsequent to its Mexican earlier sistent with the Clarendonian and younger record of occurrence. The USA record is part of the enigma of sigmodontines in North America. According to Baskin dispersal delay from Mexico (along with Capromeryx,

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Neochoerus, and perhaps Glyptotherium) and the Chrysocyon (with a Blancan record in North America; absence of certain taxa found in Central Mexico Berta, 1987); the felids Smilodon, Puma, and Panthera; (Plaina). and the camel Palaeolama. Catagonus is known from the late Hemphillian of North America and the Blancan The GABI of Mexico, as well as the Ensenadan to Recent of South America (Wright, 1998). As indicated in Appendix I all The regional basis for the main immigration episode of these taxa, possibly except Palaeolama, have a prior in North America indicates that it likely began about occurrence in North America. Depending on the age of 2.8 Ma with the first occurrence of Glyptotherium in the Ensenadan SALMA the GABI in South America central Mexico, and an entry into the United States recorded its major pulse from about 2.6–about (or older very shortly thereafter, along with Neochoerus. Most than) 1.0 Ma, fundamentally similar to the late Blancan taxa involved in the beginning of the GABI in the to early Irvingtonian in North America. USA are members of late Blancan faunas in North For North America, this “Phase One” (Webb America (2.7–1.6 Ma) and of mid and late Marplatan and Rancy, 1996) of the GABI appears to be largely (Vorohuean and Sanandresian) and Ensenadan faunas over by the end of the Blancan, at about 1.8 Ma, with in South America (from about 2.6 Ma; Figure 2; Table later gasps apparently represented by the megalony- 1; Appendix I). chid Paramylodon (Morgan, 2005), the megathere Beginning about 2.6 Ma or somewhat later, mid- Nothrotheriops (ca. 1.5 Ma), Myrmecophaga (El Golfo dle Marplatan (Vorohuean) immigrants include muste- Local Fauna, about 1 Ma; Webb, 1991), and Didelphis lids (Galictis and Stipanicicia), canids (Pseudalopex), (about 1.2–0.8 Ma in Florida and Texas; Morgan, and equids (Hippidion, Onohippidium). Late Marplatan 2005). As indicated above, a second wave of North (Sanandresian) immigrants include the first gom- American taxa entered South America between about phothere (López et al., 2001). Cervids (Epieuryceros, 1.8 and 1.0 Ma. If those correlations of Ensenadan taxa Antifer) appear in the Ensenadan. Appendix I indicates are accurate, it appears that both these and the later that North American stocks from which the dispersants North American immigrations are in the terminal part derived were present prior to the time of the GABI. of “Phase One”. For the GABI in the USA, the porcupine Erethizon The late Pleistocene phase begins about 0.8 Ma, apparently has no Mexican precursor, but accompanies with the Bonaerian (the Lujanian is restricted to the the above other two taxa to the USA at about 2.7 Ma. latest Pleistocene; Cione and Tonni, 2005) faunas Erethizon was recently identified in Sanandresian beds experiencing a number of immigrants (Marshall et in the Uquía Formation of northwestern Argentina al., 1979). These include the procyonid Nasua, the (Reguero et al., 2006). The new South American pres- mustelids Galera and Lutra, the rodent Calomys, the ence of this taxon, if endemic, implies a record in peccary Tayassu, and the cervid Ozotoceros, among South America equal to or older than 2.7 Ma. If a South others (Table 1). If most of these are Lujanian as American immigrant, this event could have trans- restricted by Cione and Tonni (2005), then they pired at about 2.0 Ma from North American Erethizon. would be about contemporaneous with those of In any case, the interval from about 2.5–2.1 Ma saw Rancholabrean age in North America, with taxa such the North American immigration of the pampatheres as Cryptotis, Sylvilagus, Lycalopex, Mustela, and Pampatherium and Holmesina, the armadillos Dasypus Mazama. For North America, the late Pleistocene and Pachyarmatherium, the megathere Eremotherium, invaders mostly do not seem to have come directly and the rodent Hydrochoerus. from South America, but reinvaded North America in In South America, Ensenadan immigrants include the Rancholabrean after having moved southward in the tapirid Tapirus; the gomphotheres Cuvieronius the late Irvingtonian: Glyptotherium, Eremotherium, and Stegomastodon; the ursid Arctotherium; the ca- Desmodus, Neochoerus, and Hydrochoerus (Morgan, nids Cerdocyon (with a Mexican progenitor) and 2005, p. 300L).

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THE PANAMA-MEXICO FAUNAL PROVINCE indicate that the group was present in Central America (Chiapas, Mexico) from about 26 Ma (Paratoceras ted- Figure 3 summarizes the record of taxa in central fordi), with the genus representing a ‘southern branch’ Mexico and in Panama that seem to pre-date their of the “Protoceratinae” and Kyptoceras the ‘southern counterparts in the USA, in addition to those found on branch’ of the Kyptoceratinae. Table 1. If the timing disjunction is accurate and per- Kirby and MacFadden (2005) evaluated the tinent, it suggests that some factor or factors seem(s) mammals of the Panamanian Gaitán Fauna (Cucaracha to retard the dispersal to the USA from this southern Formation) regarding the question of whether the body region, on the order of 1 m.y. in most cases. If the size of these taxa reflects regional isolation of island- Panamanian example is not one of dispersal lag, but like dimensions, or is within the ranges expected for one of prior lineage development, that pattern also is taxa that were not isolated from counterparts in distant not recognized in the USA at this scale for the groups locations. The goal of the investigation was to evalu- involved. Rhynchotherium provides another likely ex- ate whether Central America was a series of isolated ample of the endemic development of a lineage with islands, of which Panama was one, or whether the only subsequent manifestation in the USA, as well as region was an interconnected landscape at least dur- implications for dispersal southward. Webb and oth- ing the medial Miocene (ca. 15 Ma). They concluded ers (2003) review the history of the Protoceratidae and that the Cucaracha mammals were not isolated bio-

Figure 3. Age of selected early occurrences of taxa in Mexico and Central America relative to their USA record. Boldface numbers refer to those used in the text.

Carranza-Castañeda, Óscar, and Lindsay, E.H. eds., Advances in late Tertiary vertebrate paleontology in Mexico 2006 82 Woodburne, Cione and Tonni geographically from North American congeners, but recovered from amber-bearing beds of the Balumtum that genetic interchange occurred readily between and Sandstone (Webb et al., 2003). This unit is considered within populations at both ends of the zoogeographic to be early Miocene in age, and generally considered to extremes, north and south, at least for members of the range from 22–26 Ma. In Figure 3 the site is correlated Canidae, Oreodontidae, Protoceratidae, Equidae, and on that basis with the ‘late Arikareean.’ Rhinocerotidae. In this context the mammals surveyed As reviewed by Prothero (1998), the Protoceratidae suggest that Central America was not a series of iso- originated in North America in the Uintan (medial lated islands in the medial Miocene. Eocene, ca. 46 Ma), underwent a modest radiation In their survey of mid- to late Pleistocene faunas until the end of the Eocene (33 Ma), and persisted in in South and Central America, Webb and Rancy (1996) diminished numbers until the end of the Hemphillian show clusters of endemism, recorded by the north (ca. 4.5 Ma). One genus, Pseudoprotoceras, is present temperate mastodon, mammoth, Bison and Camelops in the Duchesnean and Chadronian (ca. 40–33 Ma.) occurring no farther south than Honduras, in Central and founded the “Protoceratinae” which also contains America, with the same faunas recording the northern- Protoceras (Whitneyan to late Arikareean, ca. 32–19 most occurrence of the South American notoungulate, Ma) and Paratoceras now known to range from late Mixotoxodon. A component of south temperate forms Arikareean (ca. 26–22 Ma) to early Clarendonian (ca. also shows regional endemism (pampas deer, pampean 10 Ma). Kyptoceratine protoceratids (Syndyoceras glyptodonts and armadillos) in southeastern Brazil and [23–18 Ma], Kyptoceros [ca. 5 Ma]) comprise the other areas of South America (see papers in Tonni and Kyptoceratini. According to Webb and others (2003), Cione, 1999). In general, however, Webb and Rancy both the “Protoceratinae” and Kyptoceratini are rep- (1996) find little other regional endemism in this resented by forms in a northern (High Plains) and part of the time scale, as well as earlier. MacFadden southern (Gulf Coastal Plain) region, including Central (2006a) provides a stimulating summary of faunal and America. In both cases the southern region taxa persist ecological evolution in Central America and the north- after the extinction of the northern forms, and are char- ern part of South America, but notes no major pro- acterized as having retreated southward “in apparent vincial differentiation within that region or relative to association with humid subtropical habitats” (Webb et adjacent areas to the north or south during the past 25 al., 2003: 363–364). In that Paratoceras was present m.y., except for the above-noted late Pleistocene pat- in the Chiapas region of Mexico as early as perhaps 26 tern that the Mexican-Central American province re- Ma, is recorded in the Cucaracha Fauna of Panama at cords the southernmost limit of Bison and Odocoileus about 17 Ma (Kirby and MacFadden, 2005), as well as virginianus (Mexico) and the northernmost limit of about 15–13 Ma in southern Texas and at about 10 Ma toxodonts from South America (Costa Rica; Lucas et in the Texas Panhandle (Prothero, 1998), the Central al., 1997). American record for the genus supports an interpreta- The evidence from some of the late Cenozoic fau- tion that it represents a group that has been endemic to nas in the Mexican-Central American region suggests this region since the late Arikareean and that subsequent a somewhat more complex pattern, on the other hand. to its apparent earlier immigration to this area from the These examples are numbered for easier reference in USA it was a member of an endemic Mexican-Central Figure 3. American biota.

Mexico 2. Early Hemingfordian. Aguascalientes (A, Figure 1)

1. Late Arikareean. Chiapas (O, Figure 1) Zoyatal Local Fauna. First nominated as early Barstovian by Dalquest and Mooser (1974), this fau- Simojovel Local Fauna. The protoceratid artiodactyl na is considered to be early Hemingfordian in age Paratoceras tedfordi is the sole taxon from this site, (Tedford et al., 2004:201R). The fossils occur in the

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Zoyatal Tuff (not dated), that contains Merychyus cf. to Ferrusquía-Villafranca (1990, 2003), who assigned elegans, Aguascalientia wilsoni, Dyseohyus cf. stirtoni, the fauna an early late Hemingfordian age (Tedford and Menoceras. Tedford and others (2004) base the age et al., 2004:202L). Syndyoceras cookei is from the largely on the oreodont Merychyus, which is a common Harrison and Marsland formations (Prothero, 1998) or early Hemingfordian taxon. If the peccary actually is Ar3 and 4, and Paratoceras is known elsewhere from Dyseohyus, it is an oldest occurrence of that genus, faunas of late Arikareean to Clarendonian age (Webb even if D. stirtoni is regarded as “Prosthennops” xiph- et al., 2003; Prothero, 1998). The Suchilquitongo pro- odonticus (Wright, 1998). toceratids are not otherwise age-diagnostic. Merychyus Dalquest and Mooser (1974) gave measurements minimus (if this is the same as M. elegans minimus in of the M3 of MU 8686 (not 8696 as stated by them) as Lander, 1998), is listed by him from the Martin Canyon 16.0 and 15.8 mm long and 16.2 and 15.9 mm wide. beds (early Hemingfordian to early Barstovian), the The length, but not the width of these teeth is compara- Lower Cady Mtn. L.F. (early Hemingfordian), possi- ble to Dyseohyus stirtoni and substantially greater than bly from the Garvin Farm L.F. (early Hemingfordian), for D. fricki or any species of Cynorca (Woodburne, and Tick Canyon Formation (Ar4). Woodburne (1998) 1969). The Mexican teeth also seem to have a more at- removed M. calaminthus (= M. elegans minimus of tenuated posterior portion of M3 than in Dyseohyus or Lander, 1998) from the Lower Cady Mts. Local Fauna Cynorca. At this point they are unlikely to be referable and indicated its age as Ar 3 (late early Arikareean). to any of these species or genera, even if D. stirtoni is In the context of Lander (1998), M. elegans minimus considered as a member of “Prosthennops” xiphodon- ranges from early Arikareean to early Barstovian, of ticus, as in Wright (1998). Nevertheless the specimens little use in close correlation. do suggest that they represent an early population of Even if the material designated as Merychippus the group to which these genera pertain and suggest the pertains to another taxon of comparable hypso- presence of such a radicle in Mexico that is unknown in donty, such as “Merychippus” or Cormohipparion coeval deposits in the USA. (Woodburne, 2003, in press), it is unlikely to be older As summarized by Wright (1998), the than 17 Ma, even if specimens from the Box Butte Tayassuini begins with “Cynorca” occidentale of late Fm. (Galusha, 1975) are so assigned (Hulbert and Hemingfordian age in North America (also Woodburne, MacFadden, 1991). The Suchilquitongo Local Fauna 1969), which forms a polytomy with Dyseohyus, first is most useful in supplying a likely late Hemingfordian known from the late Barstovian or ca. 15 Ma. If fu- age for its record of Paratoceras. ture research shows that the Zoyatal specimens per- tain to this group rather than to lineages known from 4. Late early Barstovian, Chiapas (C, Figure 1) early Hemingfordian faunas in the USA (Hesperhys, Floridachoerus), then an early tayassuine evolutionary Ixtapa Local Fauna. Ferrusquía-Villafranca (1990), theater is suggested for at least the northern part of the and Jiménez-Hildago and others (2002) indicate that Mexican-Central American province. the Ixtapa Local Fauna is from the Ixtapa Formation in the Ixtapa Graben, in Chiapas, Mexico. The site is from 3. Late Hemingfordian, Oaxaca (O, Figure 1) the lower part of the formation about 200 m below tuffs that yielded K-Ar ages of 15.02 ± 0.35 and 16.02 ± Suchilquitongo Local Fauna. This fauna is from the 0.53 Ma on biotite and plagioclase, respectively. These Suchilquitongo Formation which occurs stratigraphi- ages suggest that the fauna is not younger than early cally 80 m above tuffs dated at 19.2 ± 0.3 and 20.6 ± 0.6 Barstovian. The fauna contains Cormohipparion, Ma (Ferrusquía-Villafranca, 2003). The taxa include apparently near C. quinni, cf. Teleoceras and Merychyus minimus, Merychippus sp., a protoceratid Gomphotherium. Ferrusquía-Villafranca (1990, 2003) referred to Paratocereas, and a kyptoceratine protocer- compares the Cormohipparion with C. occidentale, atid more evolved than Syndyoceras cookei, according but this is presented as C. quinni in Tedford and oth-

Carranza-Castañeda, Óscar, and Lindsay, E.H. eds., Advances in late Tertiary vertebrate paleontology in Mexico 2006 84 Woodburne, Cione and Tonni ers (2004). As reviewed by Woodburne (in press), the 6. Early Blancan (Bl1), Guanajuato (G, Figure 1) oldest member of the C. occidentale group (C. occi- dentale, s.l.) is at about 12.5 Ma, in the Burge Member San Miguel de Allende Fauna. Capromeryx of the Valentine Formation. Cormohipparion quinni is (Artiodactyla: Antilocapridae). Jiménez-Hidalgo and first represented in the Cornell Dam Member of that others (2004) report the occurrence of Capromeryx formation, at about 14 Ma. If the Cormohipparion ma- tauntonensis from early Blancan sites in San Miguel terial proves to be referable to C. quinni (C. sphenodus de Allende, Guanajuato, Mexico. Previously the spe- in Ferrusquía-Villafranca, 2003), it would pre-date the cies was known from the Taunton Local Fauna (early earliest occurrence of that taxon in North America by Blancan) of Washington, and tentatively from the Sand about 2 m.y. (Woodburne, 1996). Draw Local Fauna (“mid” Blancan) of Nebraska, cor- The record of Gomphotherium is one of the old- related to about 3.05 to 2.7 Ma (Bell et al., 2004). The est in North America, and indicates faunal continuity Mexican occurrence is about 0.5 m.y. older than that with the west coast of the United States (late early from Taunton, and is compatible with a possible south- Barstovian North Coalinga Local Fauna), another ear- ern center of origin and diversification of the genus. ly occurrence of the genus (ca. 15.2 Ma; Tedford et al., Janis and Manning (1998) indicate that 2004). Capromeryx is one of the more derived antilocaprids and has a sister-group relationship with a clade that 5. Late early Barstovian, Oaxaca (O, Figure 1) produced Hayoceras, Stockoceras, Hexameryx, and Hexobelomeryx, with an earliest record in the early Nejapa Fauna. As summarized in Tedford and others Hemphillian (ca. 9 Ma). The intervening gap (early (2004), the El Cameron Formation contains a late early Hemphillian to early Blancan) in the USA illustrates a Barstovian fauna. The fossiliferous beds are interbed- significant absence of a record there which is compat- ded with the Yautepec Tuff dated at between 15.08 ± ible with a Central American evolutionary center lead- 0.8 Ma (biotite) and 16.7 ± 0.71 Ma (plagioclase) and ing to Capromeryx in Mexico, as well as to Tetrameryx contain material from the El Gramal Fauna site referred in the United States. to “Merychippus,” Gomphotherium, cf. Miolabis, cf. Protolabis, and a protoceratid, plus two other small Panama horses. One of these is a small hipparionine compa- rable to Hipparion shirleyi otherwise known from late 7. Late Hemingfordian or early Barstovian (P, Barstovian faunas of Texas (MacFadden, 1984). The Figure 1) other equid may be referable to Calippus. Webb and oth- ers (2003) indicate that the protoceratid is Paratoceras. Gaillard Cut Local Fauna. Kirby and MacFadden At the correlative El Camarón site taxa include the (2005) review the fauna from the Cucaracha Formation mustelid, Plionictis oacacensis, Gomphotherium, a of Panama. This fauna contains Texomys stewarti, small protohippine horse, a merycodont, small to me- Tomarctus brevirostris, cf. Cynorca, Merycochoerus dium-sized camels as well as members of the Canidae matthewi, Paratoceras wardi, Anchitherium clar- and Felidae (Tedford et al., 2004) who estimate a late encei, Archaeohippus sp., Menoceras barbouri early Barstovian age for these sites. and Floridaceras whitei. Based on the analysis of The Nejapa Gomphotherium seems to correlate MacFadden (2006b), the assemblage is a coherent fau- with that from Ixtapa, and the presence of this pro- na of contemporaneous taxa which in North America boscidean in these two sites is pertinent to the early occur in faunas of Hemingfordian (Merycochoerus Hemphillian occurrence of Rhynchotherium blicki from matthewi, Menoceras barbouri), Barstovian (Texomys Honduras (see below). The late early Barstovian occur- stewarti, Tomarctus brevirostris, Paratoceras wardi) or rence of Paratoceras adds to this taxon’s presence in of Hemingfordian-Barstovian (Anchitherium clarencei, the endemic biota of Mexico-Central America. Archaeohippus sp.) age.

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Whereas it could be straightforward to choose the (Bl 1). This clade is part of a trichotomy (New World youngest of the potential ages involved, and presume forms) that phyletically precedes a clade composed of that taxa of Hemingfordian affinity are locally persis- ‘shovel-tuskers’, of which Gomphotherium is the basal tent or undiagnostic (Archaeohippus sp.), the possibil- member and has an early occurrence of early Barstovian ity still exists that the earlier age is correct and that the in both the USA and Mexico (Nejapa, Ixtapa; Figure taxa of Barstovian affinities point to an earlier pattern 3). Tobien (1973) indicates that Rhynchotherium has of cladogenesis than would be recognized from North affinity withCuvieronius and Webb and Perrigo (1984) America. If one presumes that the Gaillard Cut Local conclude that subtropical North America (= Central Fauna is of late Hemingfordian age, and that this car- America) was an evolutionary center that resulted in ries a correlated age of about 17 Ma, then the allegedly the notiomastodonts Cuvieronius, Haplomastodon, Barstovian taxa would pre-date their North American and Notiomastodon dispersing from there to South counterparts by about 1 m.y. America. The presence of Gomphotherium in late early Barstovian faunas of Mexico indicates its presence in Honduras and El Salvador the Central American realm, compatible with a hypoth- esis of the provincial derivation of Rhynchotherium. 8. Early Hemphillian (H, Figure 1) DISCUSSION Gracias and Corinto faunas. Webb and Perrigo (1984) describe two early Hemphillian faunas from Honduras The proposal that the Neogene fossil mammal record and El Salvador, respectively. The Gracias Fauna is of Central America contains examples of endemic composed of Rhinoclemmys, Geochelone, Osteoborus evolution is discussed by Webb (1974), Ferrusquía- cyonoides, Rhynchotherium blicki, Hipparion placa- Villafranca (1984), Lindsay (1984), Webb and Perrigo tile, Pliohippus hondurensis, Teleoceras cf. fossiger, (1984), Slaughter and Ubelaker (1984; Carranza- Prosthennops cf. serus, Protolabis cf. heterodontus, Castañeda and Walton, 1992), and Jiménez-Hidalgo Procamelus cf. grandis and Pseudoceras skinneri. The and co-workers (2002), among others. All are consis- most age-significant taxa, O. cyonoides, H. plicatile, T. tent with the suggestions made herein based in part on fossiger, indicate an early Hemphillian correlation for more recent information. the fauna, with the Mixson’s Bone Bed Fauna of Florida Many of the examples cited here are based on frag- being a strong correlate, suggesting a date of about 8–9 mentary or otherwise only generally diagnostic material, Ma (Morgan, 2005) for these Central American faunas. but the published taxonomic allocations are taken as Webb and Perrigo (1984) discuss the phyletic stated for the purpose of this discussion. Whereas some position of Rhynchotherium blicki and point out that of the examples may be solved by upgrading correlations it is not only more primitive than its chronologically (numbers 3, 4, 7; and Figure 3) others seem to definitely next counterpart (R. edensis) from the Mt. Eden and indicate the likely presence of evolutionary provincial- Warren local faunas of California (correlated at about ism in the Central American region. The late Arikareean 5.2 Ma; Tedford et al., 2004), but that this is the old- occurrence of Paratoceras tedfordi in Chiapas seems est American occurrence of the genus. Lambert and to herald the presence of a protoceratid clade that un- Shoshani (1998) posit a Central American origin for derwent a distinct endemic evolutionary radiation in the group which then dispersed northward to North Mexico-Central America that persisted to within the early America, including the Blancan of Mexico (Carranza- Barstovian (numbers 1, 3, 5, 7; and Figure 3). The Zoyatal Castañeda and Miller, 2004). This is shown on Figure “Dyseohyus” (number 2; and Figure 3) either represents 3 as Rhynchotherium tlascalae. a major range extension of pre-tayassuine taxa from the Lambert and Shoshani (1998) indicate that USA, or is evidence favoring an early development of Rhynchotherium is the basal member of a clade including the tayassuine clade not identified to the north. Perhaps Stegomastodon (early record is Hh 4), and Cuvieronius the most compelling example in addition to Paratoceras

Carranza-Castañeda, Óscar, and Lindsay, E.H. eds., Advances in late Tertiary vertebrate paleontology in Mexico 2006 86 Woodburne, Cione and Tonni is number 8, where the presence of Rhynchotherium ACKNOWLEDGMENTS blicki nearly demands that the origin of this group (and its notiomastodont descendants) were unique to this re- This manuscript was initiated at the invitation of Drs. gion. The example of Capromeryx tauntonensis (num- Oscar Carranza-Castañeda, Centro de Geociencias, ber 6) speaks favorably for there having been a Central Universidad Nacional Autónoma de México, Querétaro, American center of origin for this group of antilocaprids, and E.H. Lindsay, Department of Geosciences, for which there is no record in the USA. At the moment, University of Arizona, Tucson; the first author thanks the potentially earlier age of Plaina in Mexico versus the them for not only the invitation, but also help and encour- Chapadmalalan of South America (Table 1) also permits agement along the way. Other colleagues who provid- consideration of the role played here by the Mexican- ed assistance include Drs. Gary Morgan, New Mexico Central American province. Museum of Natural History, Albuquerque, and Bruce In addition to Cerdocyon, immigrant to South J. MacFadden, Florida Museum of Natural History, America in the Ensenadan from a prior apparent an- Gainesville, with especial insight into Neotropical fau- cestor in Mexico, Berta (1987) reviews the remaining nas both north and south of the Panamanian isthmus. South American canids and comments as to a possi- ble Central American center of diversification for the LITERATURE CITED group. In that context it is informative that new taxa appear in both the Marplatan and Ensenadan on Table Alberdi, M.T., and Prado, J., 1992, El registro de Hippidion Owen, 1986, y Equus (Amerhippus) Hoffstetter, 1950 (Mammalia, 1, suggesting at least two separate dispersal episodes. Perissodactyla) en América del Sur: Ameghiniana, v. 29, p. Regarding rodents, Carranza-Castañeda and 265–284. Walton (1992) point to a late Hemphillian diversifi- ――― 1993, Review of the genus Hippidion Owen, 1869 cation of sigmodontines in Mexico prior to their dis- (Mammalia, Perissodactyla) from the Pleistocene of South persal to South America, and the Mexican occurrence America: Zoological Journal of the Linnean Society, v. 108, of Neochoerus pre-dates its Barrancalobian record in p. 1–22. ――― 1995, Los mastodontes de América del Sur, in Alberdi, South America. M.T., Leone, G. and Tonni, E.P., eds., Evolución biológica At this point, it is obvious that with the potential y climática de la región pampeana durante los últimos cinco exception of the late Pliocene and Pleistocene canids millones de años: Madrid, Monografías del Museo Nacional (if they had a Central American radiation), and the de Madrid, 12, p. 279–292. earlier record of Tomarctus in Honduras, the groups Alberdi, M.T.; Prado, J.L.; and Salas, R., 2004, The Pleistocene involved all are herbivores and mostly ungulates. But Gomphotheriidae (Proboscidea) from Peru: Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 231, p. 423– mesodont to early hypsodont horses (merychippines 452. and Cormohipparion) are not likely to have been mem- Ameghino, F., 1908, Las formaciones sedimentarias de la región bers of the same ecologic or adaptive facies as were litoral de Mar del Plata y Chapalmalán: Anales del Museo peccaries, proboscideans, antelopes, or sigmodontine Nacional de Historia Natural de Buenos Aires, v. 3, p. 343– and hydrochoerid rodents, even if all were basically sa- 428. vanna-dwellers (e.g., Webb, 1991). Preceding sections Bagnalasta, M.B., 1980, Algunas consideraciones sobre la validez del género Epieuryceros Ameghino, 1889: Actas del II recall numerous references attesting to changes in cli- Congreso Argentino de Paleontología y Bioestratigrafía y mate and tectonic setting in this region over the past 9 I Congreso Latinoamericano de Paleontología 3, p. 183– m.y., as well. Thus it is unlikely that whatever kinds of 192. provincialism operated, there was no single cause for Baskin, J.A., 1978, Bensonomys, Calomys, and the origin of the patterns articulated above. Whatever their causes, the phyllotine group of Neotropical rodents (Rodentia: patterns of secular evolution as well as chronologic Cricetidae): Journal of Mammalogy, v. 59, no. 1, p. 125– 135. disjunctions in dispersal demonstrate the importance of ―――1986, The late Miocene radiation of Neotropical sigmodontine Central America’s role in the Neogene faunal develop- rodents in North America: Contributions in Geology, ment of North and South America. University of Wyoming, Special Paper, 3, p. 287–303.

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California, in Terry, D.O.; LaGarry, H.E.; and Hunt, R.M., (Morgan, 2005), but the tribe Thinobadistini is known Jr., eds., Depositional environments, lithostratigraphy, and from approximately coeval Huayquerian deposits of biostratigraphy of the White River and Arikaree Groups South America (M&B 00). Morgan (2005) indicates (late Eocene to early Miocene, North America): Geological that Thinobadistes is only distantly related to Society of America Special Paper 325, p. 197–210. Glossotherium. The >8 Ma age for the McGehee Farm Woodburne, M.O., 2003, Craniodental analysis of Merychippus and Mixson’s Bone Bed sites advocated by Morgan insignis and Cormohipparion goorisi (Mammalia, Equidae), (2005) is older than in Tedford and others (2004; ca. Barstovian, North America: American Museum of Natural History Bulletin, v. 13, no. 279, no. 397–468. 7.5–8 Ma). Morgan (2005) suggests an age of 8.0–8.5 ――― in press, Phyletic diversification of the Cormohipparion Ma for the Mixson’s site, following Hulbert (2001). occidentale Complex (Mammalia; Perissodactyla, Equidae), late Miocene, North America, and the origin of the Old Megalonyx (Xenarthra; Megalonychidae). This sloth is World Hippotherium Datum: American Museum of Natural endemic to North America (Morgan, 2005), and History Bulletin. apparently evolved from Pliometanastes. It is known Woodburne, M.O., and Swisher, C.C., III., 1995, Land mammal only from North and Central America (M&B 00). high-resolution geochronology, intercontinental overland Megalonyx curvidens is recorded in the Aphelops dispersals, sea level, climate, and vicariance, in Berggren, Draw Fauna of early Hemphillian age (Hh 2; Tedford W.A.; Kent, D.V.; Aubry, M.P.; and Hardenbol, J., eds., et al., 1987:171L; Tedford et al., 2004; Fig. 6.2; ca. 7.2 Geochronology, time scales, and global stratigraphic Ma). Morgan (2005) shows Megalonyx present in the correlation: Society of Economic Paleontologists and Palmetto Fauna of Florida (ca. 5.2 Ma), comparable to Mineralogists Special Publication, v. 54, p. 334–364. its 5.2 Ma age in the Pinole Local Fauna of California (Hh 3; Tedford et al. [1987, 2004]). Flynn and others APPENDIX I (2005) report Megalonyx as occurring at about 4.8 Ma in the Guanajuato area of Mexico. Contrary to Time and Entry Flynn and others (2005), the Mexican record does not represent a pre-USA element of GABI. This summarizes the evidence for the timing and taxa involved in the dispersal. *Underlined taxa are immigrants Kraglievichia (Xenarthra, Pampatheriidae). Chasicoan to to South America (also on Table 1). Taxa indicated as e are Huayquerian of South America. Contrary to other endemic to South America, having been locally derived after opinions, the North American records are dismissed immigration. All chronologic references to Vrba (1993) (Edmund, 1987; Scillato-Yané et al., 2005). reflect only the earliest record of the taxon in question, not its entire geochronological range. M&B 00 refers to McKenna Huayquerian ca. 9.0–6.8 Ma and Bell (2000), the searchable version of McKenna and Bell (1998). SALMA units are underlined. Flynn and Swisher (1995) indicate an age from 9.0–7.0 Ma. Butler and others (1984) and Marshall and others (1992) Early Hemphillian, ca. 9 Ma present evidence that the Huayquerian-Montehermosan boundary is about 6.0 Ma. Cione and others (2001) summarize Pliometanastes (Xenarthra: Megalonychidae) is known evidence in favor of an upper limit of about 6.8 Ma. See only from North America, but the subfamily Cione and Tonni (2005), and discussion under Cyonasua. Megalonychinae is known from coeval deposits in South America (Megalonychops) according to M&B *Cyonasua (Carnivora: Procyonidae). Cyonasua is known 00. Morgan (2005) indicates that Pliometanastes has from the Huayquerian to the Chapadmalalan of South its earliest occurrence in the McGehee Local Fauna of America (Cione and Tonni, 1995; Cione et al. 2001). Florida, of early Hemphillian (Hh 1) age, or at about Chapadmalania is a closely related taxon that is known 8–9 Ma. from the Chapadmalalan to Vorohuan and perhaps Montehermosan; the Huayquerian record is erroneous Thinobadistes (Xenarthra: Mylodontidae) is only known (Cione and Tonni, 1996; Daniel Berman, 2006, from North America. Its earliest occurrence is in personal communication). The subfamily Procyoninae the McGehee Farm Local Fauna at ca. 8.5–9 Ma

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is recorded from the early Miocene of North America Ma, with paleomagnetic evidence suggesting a 4 Ma age for (M&B 00; Marshall et al., 1983). Butler and others the base of the upper Chapadmalalan (Orgeira and Valencio, (1984) correlated northwestern Argintinian specimens 1984). Bolivian sediments with mammals were considered of Huayquerian age referred to Cyonasua as between to be Chapadmalalan sensu lato by Cione and Tonni (1996), 7.0 and 7.5 Ma. This appears to be the oldest known and could be as old as 5.4 Ma according to radioisotopic record of carnivores in South America and the oldest ages obtained from underlying tuffaceous beds (Cione and known representatives of the interchange in South Tonni, 1996). On this basis the lower Chapadmalan should America. Fossils attributed to the more advanced be older. In Puerta de Corral Quemado, Catamarca Province, endemic genus Chapadmalania by Butler and others Argentina, a specimen of Chapadmalania, Chapadmalalan (1984) and Marshall and others (1979) from Corral genus, “probably” comes from a level dated at 5.4–5.8 Ma Quemado, Cataqmarca, northwestern Argentina, are (Butler et al., 1984, p. 634). The 5.0 Ma age chosen in Figure correlated to an age of about 5.4–5.8 Ma. However, 2 reflects these uncertainties. the provenance is uncertain because the material was Furthermore, Montehermosan taxa derive only from “collected between units 15 and 32 (probably from the type of that unit near Pehuencó, Argentina, where it is unit 21) of the Corral Quemado Formation” (Marshall about 2-m thick and underlies the type Chapadmalalan. All et al., 1979, p. 276). Units 15 to 32 have radioisotopic other sections considered to be Montehermosan in age are dates that range from 6.7 Ma to less than 3.54 Ma. doubtful or appear to be Chapadmalalan (Cione and Tonni, Chapadmalania is certainly known in the type upper 1996). Chapadmalalan in beds dated approximately as old as 3.3 Ma and in correlative beds in the Huayqueras de *Sigmodontine rodents. According to Baskin (1986) San Carlos, Mendoza Province, Argentina (Cione and Abelmoschomys, from the latest Clarendonian Love Tonni, 1996; Schultz et al., 1998). Bone Bed of Florida, is an early sigmodontine rodent from the USA. Antecalomys (Korth, 1998) is a Late Hemphillian ca. 6.8–4.9 Ma and Montehermosan, ca. contemporaneous form from Nebraska. McKenna and 6.8–5.0 Ma Bell (1998) include Abelmoschomys in the subfamily Cricetodontinae, however. Baskin (1978) described Traditionally, Chapadmalalan and Montehermosan were the late Hemphillian Bensonomys from Arizona and considered as separate units (Kraglievich, 1934; see placed it as a subgenus of the living South American discussion in Cione and Tonni, 1995, 1996). However Pascual genus, Calomys. Bensonomys also occurs in the late and others (1965) incorporated the Chapadmalalan into the Hemphillian Yepómera (Lindsay and Jacobs, 1985) Montehermosan, mixing the faunal lists. Marshall and others and El Ocote (Carranza-Castañeda and Walton, (1984) recognized the Chapadmalalan as a separate unit, 1992) faunas of Mexico. Other North American but the faunal list was mixed and included taxa from units sigmodontines include Repomys (late Hemphillian to of Huayquerian, Montehermosan, and Chapadmalalan age late Blancan; Tedford et al., 1987), and Jacobsomys, (see Cione and Tonni, 1995). Reliable Chapadmalalan and early Blancan Verde Fauna, Arizona (Czaplewski, Montehermosan lists appear beginning in papers by Tonni 1987). Jacobsomys is tentatively assigned to the and others (1992a, b), Cione and Tonni (1995, 1996, 1999, sigmodontines by McKenna and Bell (1998). 2005), Deschamps (2004). Marshall and Sempere (1993) Baskin (1986) summarizes evidence in favor of the combined the Chapadmalalan and “Uquían” in a single unit; origin and diversification of sigmodontine rodents in this view is not followed here. North America prior to their dispersal to South America The upper boundary of the Chapadmalalan is at in the Montehermosan at about 3.5 Ma (modified here about 3.3 Ma (Schultz et al., 1998). However the age of to about 5.7 Ma; Figure 2). Sigmodontine records are the lower boundary of the Chapadmalalan is unknown as is extremely rare in the Montehermosan (Pardiñas and the duration of the Montehermosan. The 4.0 Ma age for the Tonni, 1998). Remarkably, all South American cricetids Chapadmalalan-Montehermosan boundary shown in Cione pertain to endemic genera. Reig (1981) proposed that and Tonni (2005) is conventional. Actually little is known of cricetids entered South America in the late Miocene. the ages within the interval from about 7.0 to 4.0 Ma. It is highly New evidence from the Cerro Azul Formation in probable that Chapadmalalan faunas could be older than 4.0 La Pampa Province (central Argentina) could bring

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new insights regarding the problem (Montalvo et al., According to Flynn and others (2005) Glossotherium 2000). occurs in early Blancan (4.7–4.8 Ma) deposits in The South American genus Calomys is not a synonym Mexico, but not until the late Blancan, about 2.8 Ma of Bensonomys according to most recent authors (Lower Cita Canyon and Blanco faunas; Bell et al., (Pardiñas et al., 2002), who consider Bensonomys to 2004:268) in the United States. Morgan (2005) shows be a peromyscine, not a sigmodontine. Recognizing Glossotherium as present in the late Blancan Macasphalt that the North American genera Abelmoschomys and Shell Pit, Kissimmee River and Haile 15A local faunas Bensonomys are older than the oldest-known South in Florida considered by him to be at about 2.2–2.7 American sigmodontines, it is important to establish Ma. Tomida (1987) reported Glossotherium from the their phyletic affinities (Pardiñas et al., 2002: 240). 11 Mile Wash Local Fauna in Arizona, correlated to about 3.5 Ma (revised to about 3.0 Ma in Bell et al., *Auliscomys (Rodentia, Sigmodontinae). Cione and 2004; Country Club fauna). Tonni (2005) indicate this genus is characteristic of Esteban (1996) considers that all North American the Montehermosan Trigodon gaudryi biozone in specimens referred to Glossotherium (including those Argentina (see also Pardiñas and Tonni, 1998; M&B of the Hemphillian of Mexico) are referable to the genus, 00. See also Necromys. Paramylodon. According to this study, Glossotherium should be an endemic South American genus. Thus eNecromys (Rodentia, Sigmodontinae). Cione and Tonni Esteban (1996) considers that the specimens identified (2005) indicate this genus is characteristic of the as Glossotherium chapadmalensis from North America Montehermosan Trigodon gaudryi biozone of do not belong to this genus and/or species. This Ph. D. Argentina. It was cited as Bolomys by Vrba (1993) and dissertation remains unpublished, however. M&B 00. Bolomys is currently considered as a junior synonym of Necromys (Wilson and Reeder, 2005). Plaina (Xenarthra: Pampatheriidae). Scillato-Yané and others (2005) consider Plaina a valid genus. Morgan (2005) Early Blancan (Bl1, ca. 4.8–3.5 Ma), and Chapadmalalan, indicates that Carranza-Castañeda and Miller (2004) ca. 5.0–3.3 Ma have distinguished as Plaina material from Mexico formerly referred to Holmesina or Pampatherium. See the discussion above regarding the Montehermosan. Flynn and others (2005) record Plaina from the As indicated in Figure 2, the Chapadmalalan is considered Guanajuato district in late Hemphillian faunas at about to range in age from about 5.0 to 3.3 Ma, but its base is 4.6–4.7 Ma. Cione and Tonni (1996, 2005) indicate not calibrated. An “escorias” bed near the top of the upper its oldest South American record is in the type early Chapadmalalan near Mar del Plata, Buenos Aires Province, Chapadmalalan near Pehuencó, southern Buenos Aires Argentina, is dated about 3.3 Ma (Schultz et al., 1998). Province, Argentina (Neocavia depresidens biozone; Cione and Tonni (1995) indicate that the Chapadmalalan is about 4 Ma or older; Figure 2), and the younger beds pre-Uquían in the sense that the Uquían is replaced by the of the type late Chapadmalalan near Mar del Plata, Marplatan, which begins about 3.2 Ma in their correlation both in southern Buenos Aires Province, Argentina (Cione et al., 2001). (Paraglyptodon chapadmalansis biozone; somewhat older than 3.3 Ma). It also occurs in Chapadmalalan Glossotherium (Xenarthra: Mylodontidae). Glossotherium beds of the Tunuyán Formation, Mendoza Province, is known in South America from the type upper Argentina, and at Inchasi, Bolivia (Cione and Tonni, Chapadmalalan, Buenos Aires Province, Argentina, 1996). to uppermost Lujanian in different locations in the Pampean region, according to Cione and Tonni Pampatherium and Holmesina (Xenarthra: Dasypdidae). (1995; but not Cione and Tonni, 2005), or from levels M&B 00 consider Pampatherium as a junior synonym somewhat older than 3.3 Ma to 0.01 Ma. The genus of Holmesina which Morgan and Hulbert (1995) show Glossotherium Kraglievich, 1934 is a junior synonym as having a first appearance in the Santa Fe River Local of Glossotherium Owen, 1839. In North America Fauna correlated as about 2.4 Ma and late Blancan. Glossotherium typically is found in the Blancan. Scillato-Yané and others (2005) suggest that both

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Pampatherium and Holmesina are valid genera, the *eReithrodon (Rodentia, Sigmodontinae). Reithrodon latter probably derived in North America from Plaina ranges from Chapadmalalan to Recent (Tonni et al., or Kraglievichia and dispersed to South America in the 1992; Cione and Tonni, 1995; M&B 00). This is an latest Pleistocene (Lujanian; Cione and Tonni, 1999). endemic genus. Ptyssophorus (in Vrba, 1993) is a Flynn and others (2005) consider Pampatherium as a subgenus of Reithrodon in M&B 00, but is considered synonym of Kraglievichia. Kraglievichia is restricted a junior synonym of Reithrodon in Pardiñas and others to South America according to Edmund (1987). Flynn (2002). and others (2005) may believe that Kraglievichia pertains to Holmesina floridanus. Edmund (1987) and *eZygodontomys (Rodentia: Sigmodontinae). The taxon Scillato-Yané and others (2005) retain H. floridanus as ranges from Pleistocene (only in Aruba) to Recent separate from Kraglievichia. of South America, and Recent of Central America Pampatherium is a South American taxon with an according to M&B 00. Ensenadan oldest record. It probably descended from Vassallia and dispersed to North America during the *eArgyrohyus (Artiodactyla: Tayassuidae). M&B 00 list Pleistocene (Scillato-Yané et al., 2005). The only this endemic genus as Chapadmalalan, consistent certain North American Pampatherium appears with Cione and Tonni (1995). It first occurs in the to be P. mexicanum from the Pleistocene beds of late Chapadmalalan Paraglyptodon chapadmalensis Puebla, Hidalgo, and Jalisco, Mexico (Scillato-Yané biozone of Cione and Tonni (2005), correlated as about et al., 2005). However, Carranza-Castañeda (2006, 3.3 Ma or somewhat older. personal communication) indicates that scutes closely resembling those of Pampatherium occur at Arroyo *Platygonus (Artiodactyla: Tayassuidae). Platygonus occurs Belén, Guanajuato, in early Blancan beds dated at in the upper Chapadmalalan to Ensenadan according about 3.6–3.9 Ma. Pampatherium may have dispersed to Cione and Tonni (2005). It is present for the first to North America in the late Blancan. time, along with Argyrohyus in the late Chapadmalalan (see above). Tedford and others (2004) indicate the *eChapadmalania (Carnivora: Procyonidae). Chapadmalania genus is present in Hh2 faunas of North America at is a descendant of Cyonasua. Chapadmalania appears about 7.2 Ma. to be exclusive to the Chapadmalalan (Cione and Tonni, 1995). Marplatan, ca. 3.2–2.0 Ma

*eAkodon (Rodentia, Sigmodontinae). This genus ranges The chronology follows Cione and others (2001) and from the late Chapadmalan to Recent, following Tonni Cione and Tonni (1995, 2005) and effectively replaces and others (1992) and Cione and Tonni (1995). Akodon the Uquían SALMA, which Flynn and Swisher (1995) apparently is an endemic taxon. M&B 00 agree. Vrba correlate to about 3.0–1.5 Ma. The Marplatan is composed (1993) lists the genus as early Chapadmalalan. of three subages, the Barrancalobian (about 3.2–3.0 Ma), Vorohuean (about 3.0–2.4 Ma) and Sanandresian (about *eDankomys (Rodentia, Sigmodontinae). This genus ranges 2.4–2.0 Ma). from Chapadmalalan to Vorohuean (Tonni et al., 1992; Cione and Tonni, 1995). M&B 00 extend the range to *Dusicyon (Carnivora: Canidae). Berta (1987; see also Sanandresian. Vrba (1993) lists the endemic genus as Prevosti et al., 2005) indicates that this genus (as early Chapadmalalan. Pseudalopex) ranges from Uquían to Recent in South America, with Uquían here refined to Marplatan *eGraomys (Rodentia, Sigmodontinae). This endemic genus (Vorohuean), and correlated to about 2.5 Ma in ranges from the late Chapadmalalan to Sanandresian Cione and Tonni (2001). Vorohuean is represented (M&B 00; Cione and Tonni, 1995, 2005). Dankomys, by the Akodon (Akodon) lorenzinii biozone in Cione Graomys, Reithrodon, and Zygodontomys were included and Tonni (2005). The reference to Canis in the incorrectly in the early Chapadmalalan by Vrba (1993). Marplatan by Tonni and others (1992) corresponds In Table 1 a late Chapadmalalan age is shown. to Dusicyon.

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*eStipanicicia (Carnivora: Mustelidae). This endemic genus Erethizon (Rodentia: Erethizontidae). The genus is known is known in Sanandresian and Ensenadan deposits from the Wolf Ranch Local Fauna of Arizona (Bell according to Cione and Tonni (1995), followed here. et al., 2004), at about 2.7 Ma. Other occurrences cited in Bell and others (2004) are younger than that. *eGalictis (Carnivora: Muselidae). M&B 00 show it as from M&B 00 show its range from late Pliocene to Recent. the Recent of North, Central and South America, Morgan (2005) indicates that the oldest known record with a probable record in North and South America of Erethizon dorsatum is from the site Haile 16A, (Ensenadan) into the early Pleistocene. Cione and correlated at about 1.6 Ma, but other (extinct) species Tonni (1995) show it in the Vorohuean to Recent. The in Florida are late Blancan, ca. 2.2–2.7 Ma, compatible Vorohuean is the oldest record of the genus in South with the Wolf Ranch record. America (a Chapadmalalan record was considered as Reguero and others (2006) reported the occurrence highly dubious by Cione and Tonni, 1995). of Erethizon from Sanandresian beds of the Uquía Formation of northwestern Argentina. This is the only eScapteromys (Rodentia: Sigmodontinae). M&B 00 indicate record of the North American genus in South America, an Uquían to Recent range for this endemic genus. and might reflect a dispersal about 2.0 Ma, but also Vrba (1993) lists it as “Uquían.” Tonni and others could imply an earlier record in South America with (1992) and Cione and Tonni (1995) show a Vorohuean dispersal northward. to Recent range, followed here. Late Blancan ca. 3.0–1.8 Ma *Lama (Artiodactyla: Camelidae). Cione and Tonni (1995, 2005) indicate a Marplatan (Barrancalobian) to Recent Glyptotherium (Xenarthra: Glyptodontidae). M&B 00 age for this immigrant genus of a Holarctic family. The indicate a range of late Blancan to Rancholabrean for genus Vicugna is shown as Ensenadan to Recent in this Central and North American genus, consistent M&B 00, and as Ensenadan in Vrba (1993). However with Bell and others (2004) and Morgan (2005), who it is included within Lama in Marshall and others note that Glyptotherium appears about 2.5 Ma in (1983) and Cione and Tonni (2005). the Upper Cita Canyon Local Fauna and in the 111 Ranch fauna of Arizona. The first occurrence of about *Hippidion (Perissodactyla: Equidae). Alberdi and Prado 3.6 Ma in Figure 7.2 (Bell et al., 2004) apparently (1992, 1993) consider Onohippidium as a junior is a drafting error (E. Lundelius, 2-17-06, personal synonym of Hippidion. Other authors consider communication). Flynn and others (2005) indicate it a valid genus (MacFadden and Skinner, 1997; that Glyptotherium first appears at about 2.8 Ma in MacFadden, 1997). Cione and others (2003) list the the Guanajuato district of Mexico. Morgan (2005) immigrant equid as Marplatan to uppermost Lujanian. notes the presence of Glyptotherium in early Blancan MacFadden and Skinner (1979) record the genus in faunas of North America (nominally the USA) at about the early Hemphillian of Texas (ca. 9 Ma) as well 2.5–2.7 Ma. At the level of resolution, the geochron of as in the Irvingtonian of California (Tedford et al., Glyptotherium is the same in Mexico as in the USA. 2004). Kraglievichia (Xenarthra: Pampatheriidae). Although it has *Onohippidium (Perissodactyla: Equidae). Specimens been cited for North America, it is not present in this assigned to Onohippidium in Vorohuean beds near Mar region (see comments on Pampatherium, above). del Plata, Buenos Aires Province, Argentina, represent the oldest record of Equidae in South America (see Holmesina (Xenarthra: Pampatheriidae). This genus is Reig, 1957; Tonni and Cione, 2000; Cione and Tonni, known from deposits in Florida at ca. 2.4 Ma (Bell 2005). Prado and others (1998) mistakenly proposed et al., 2004). Morgan (2005) cites the presence of that the oldest material of Equidae in South America Holmesina in the Macasphalt Shell Pit and Haile 15A came from Sanandresian beds in the Uquía Formation, local faunas correlated by him at about 2.2–2.7 Ma in Jujuy, northwestern Argentina (see Tonni and Cione, (Haile 15A is correlated at 2.3 Ma). See comments on 2000). Pampatherium, above.

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Dasypus (Xenarthra, Dasypodidae). Species of Dasypus is correlated as about 2.2 Ma by Bell and others (2004) inhabit South and North America today. This genus and about 2.3 Ma by Morgan (2005). is known from deposits in Florida at ca. 2.4 Ma (Bell et al., 2004). Morgan (2005) cites the presence of Tremarctos (Carnivora; Ursidae). This genus is known Dasypus bellus in the Macasphalt Shell Pit and Haile from two species, T. floridanus (Gidley) from the late 15A local faunas correlated by him at about 2.2–2.7 Pliocene and Pleistocene of North America, and T. Ma (Haile 15A is correlated as 2.3 Ma). If this generic ornatus in the Recent of South America, where it is assignment is correct, Dasypus would be older in North the only living tremarctine. It has not been found as a America than in South America. The species D. bellus fossil in South America. actually should be referred to Propraopus (Alfredo Carlini, 2006, personal communication). Propraopus Ensenadan, ca. 2.0–0.7 Ma is known from the Ensenadan (Cione and Toni, 2005), but it might also occur in Chapadmalalan or Marplatan This follows Cione and others (2001). Flynn and Swisher strata (Ameghino, 1908). (1995) correlate the Ensenadan from about 1.2 to 0.7 Ma. MacFadden (2000) indicates an age for the Ensenadan/ Pachyarmatherium (Xenarthra: Glyptodontidae). Morgan Lujanian boundary as 0.7–0.6 Ma. This does not include (2005) records this apparently immigrant glyptodont the Bonaerian (e.g., Cione and Tonni, 1999, 2001, 2005) in the Kissimmee River, Haile 16A and Leisey Shell which relegates the Lujanian to very late Pleistocene. The Pit local faunas at about 2.4–1.4 Ma in Florida. Bonaerian is ca. 0.7–0.125 Ma, whereas Lujanian ranges from 0.125–0.08 Ma (Cione et al., 2003; Verzi et al., 2004). Paramylodon (Xenarthra: Mylodontidae). Morgan (2005) Many taxonomic references to the Lujanian in prior literature records this North American taxon (P. harlani) from use the Lujanian as the interval next after the Ensenadan. faunas at about 1.8 Ma in Florida (Inglis 1A, 1C, Haile 16A, Leisey Shell Pit, Haile 21A). *Chrysocyon (Carnivora: Canidae). Berta (1987) lists this genus as Ensenadan to Recent. However there are only Eremotherium (Xenarthra: Megatheriidae). Bell and others a few fossils from the Tarija Formation of Bolivia of this (2004) indicate that Eremotherium occurs in Florida age. Now known as the Tolomosa Formation, the unit faunas at about 1.77 Ma (De Soto Shell Pit; Inglis 1A). is composed of two parts. The lower interval consists Morgan (2005) concurs in the late Blancan age, but of poorly fossiliferous clays, and the upper, highly apparently considers it to be somewhat older, from The fossiliferous, interval is composed of conglomerates. Kissimmee River Local Fauna (2.2–2.7 Ma). The basal age of the lower unit is about 1 Ma and could be regarded as Ensenadan on that basis, but not on its Neochoerus (Rodentia: Hydrochoeridae). The genus is fossil content. The upper unit is younger than 0.78 Ma known from the 111 Ranch Local Fauna in Arizona (Soibelzon et al., 2005). Chrysocyon was not listed in (Bell et al., 2004), about 2.6 Ma. Morgan (2005) cites Tonni and others (1992) or Cione and Tonni (1995) the presence of Neochoerus in the Macasphalt Shell Pit because it is not present in southern South America Local Fauna correlated by him at about 2.2–2.6 Ma. until late Platan (Prevosti et al., 2004). Berta (1987) Flynn and others (2005) indicate that Neochoerus is groups this genus with ‘true’ wolves of South America: recorded in Mexican deposits at about 3.3 Ma. In South Canis gezi, Canis nehringi and Canis dirus (see America Neochoerus is known from the Ensenadan comments below). Chrysocyon is also known from the and Lujanian (Deschamps, 1998; Cione and Tonni, early Blancan of North America, so is an immigrant to 1999, 2005). It is tempting to consider a Neotropical South America. source for the South American record, although it may turn up in the Marplatan. *Cerdocyon (Carnivora: Canidae). Marshall and others (1983) show this apparently immigrant taxon is Ensenadan Hydrochoerus (Rodentia: Hydrochoeridae). The oldest and Lujanian to Recent. M&B 00 indicate it has a record of this rodent is from the late Blancan Haile late Pleistocene to Recent record in South America, 15A site, Florida, by Morgan and Hulbert (1995). This but also a late Miocene to early Pliocene record in

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North America (USA, Mexico; late Hemphillian and extinct during the early Holocene, approximately early Blancan, respectively; Torres and Ferrusquía, synchronous with their extinction in North America 1981; Berta, 1987). R.H. Tedford (2-21-06, personal (Soibelzon et al., 2005). communication) indicates that the USA record of Cerdocyon is from the late Hemphillian fauna of *Smilodon (Carnivora: Felidae). Tonni and others (1992) Rentfro Pit 1, Ogallala Grp., near Channing, Texas. and Cione and Tonni (1995) show that the genus Torres and Ferrusquía (1981) consider the Mexican ranges from Ensenadan to Lujanian. Smilodontidion species closest to the South American C. thous. The is a junior synonym of Smilodon based on juvenile genus apparently arose in North America. It is not material (Cione and Tonni, 1995). It was referred to listed in Tonni and others (1992) or Cione and Tonni Vorohuean (M&B 00), but this is an error. (1995) because the genus is not recorded in southern South America. * “Felis” (Carnivora: Felidae). Vrba (1993) records this immigrant genus from the Ensenadan. Tonni and *eTheriodictis (Carnivora: Canidae). Vrba (1993) indicates others (1992) and Cione and Tonni (1995) show it an Ensenadan age as do Cione and Tonni (1995) for from Ensenadan and Lujanian to Recent. However, Theriodictis. The species Canis gezi actually is a the only certain reference to Felis in South America is junior synonym of Theriodictis platensis (Prevosti, based on Felis cattus from latest Holocene sediments 2001). Berta (1987) records Theriodictis from the of Buenos Aires Province, Argentina, a probable Lujanian of Ecuador, but Prevosti (2004) considers result of Hispanic immigration (Prevosti, in press). that this material probably is assignable to Protocyon “Felis” vorohuensis and “Felis” sp., both of uncertain troglodytes. systematic position, occur in the Ensenadan of Buenos Aires Province, Argentina (Prevosti, in press). Tedford *Protocyon (Carnivora: Canidae). Tonni and others (1992) and others (1987, 2004) record Felis rexroadensis from and Cione and Tonni (1995) show the genus as present the Hh3 Upper Bone Valley Local Fauna, Florida. in the Ensenadan and Lujanian. “Uquían” references (Vrba, 1993) are erroneous. *Felis (Carnivora: Felidae). Vrba (1993) records the genus from the Ensenadan. Tonni and others (1992) and *?Conepatus (Carnivora: Mustelidae). This genus is known Cione and Tonni (1995) show it from the Ensenadan from Ensenadan to Recent deposits in South America, and Lujanian to Recent. This is consistent with M&B according to Cione and Tonni (1995), who rejected 00. It also is listed by M&B 00 from the early Pliocene an early Chapadmalalan age (Vrba, 1993). In any (= early Blancan). case, the genus is known only from Irvingtonian and younger times in North America (e.g., M&B 00, Bell *Puma (Carnivora: Felidae). The Puma is known from et al., 2004). At present, it appears that the northern the Ensenadan in southern Buenos Aires Province, and southern first occurrences might be coeval at the Argentina (Marshall et al., 1984; Pomi and Prevosti, available level of resolution. 2005).

*eLyncodon (Carnivora: Mustelidae). This endemic genus is *eLynchailurus (Carnivora: Felidae). This South American known from the Ensenadan of Buenos Aires Province, genus is known from Ensenadan beds at Camet, Argentina, to Recent (Cione and Tonni, 2005). Buenos Aires Province, Argentina (Prevosti, in press).

*eArctotherium (Carnivora: Ursidae). The Tremarctinae in *eCalomys (Rodentia: Sigmodontinae). See comments on North America range from Hemphillian (Plionarctos Sigmodontinae. M&B 00 cite Marshall and others sp., Hh 3, Tedford et al., 2004) to Rancholabrean (P. (1984) for an Ensenadan-Lujanian duration of this floridanus and Arctodus simus). In South America endemic genus. Vrba (1993) cites an “Uquían” age. the first record corresponds to the Ensenadan It does not occur in the Marplatan but is known (Arctotherium latidens) and continues to the present as from the Ensenadan according to Cione and Tonni Tremarctos ornatus, but the short-faced bears become (1995). Carranza-Castañeda and Walton (1992) record

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Calomys (Bensonomys) from the late Hemphillian El *eAntifer (Artiodactyla: Cervidae). Bagnalasta (1980) Ocote Local Fauna. considers Antifer as a valid endemic genus. It ranges from the Ensenadan to Bonaerian (Cione and Tonni, *eLundomys, Oxymycterus, Phyllotis, Holochilus (Rodentia: 1999). Sigmodontinae). All these genera occur in the Mesotherium cristatum biozone (Ensenadan) to Recent *Tapirus (Perissodactyla: Tapiridae). This genus is listed as (Pardiñas, 1993, 2004). “Uquían” in Vrba (1993), and Ensenadan to Recent in Tonni and others (1992), Cione and Tonni (1995, *eCatagonus (Artiodactyla: Tayassuidae). This endemic 2005) and M&B 00, who also point out that the genus peccary is listed as Ensenadan to Recent in Marshall is represented in the late Miocene of Holarctica. and others (1983), Vrba (1993), M& B00, and Cione and Tonni (2001; 2005). *Stegomastodon (Proboscidea: Gomphotheriidae). Cione and Tonni (1995, 2005) report Stegomastodon from *Hemiauchenia (Artiodactyla: Camelidae). Tonni and others the Ensenadan and Lujanian. Prado and others (2003) (1992) and Cione and Tonni (1995) show an Ensenadan synonymized Notiomastodon with Stegomastodon to Lujanian age for this immigrant taxon. M&B 00 (see Cione et al., 2005 and references therein). An show a middle Miocene (early Clarendonian) to late indeterminate gomphotheriid was reported from the Pleistocene (Rancholabrean) record in North America, Sanandresian beds of the Uquía Formation in Jujuy late Pliocene to Recent in South America. Meachen Province, Argentina (López et al., 2001). M&B 00 (2005) discusses Hemiauchenia species from Florida report Stegomastodon from the early to late Pleistocene (1.8–2.5 Ma) and their possible relationship to the of South America and from the early Pliocene to late ancestry of lamines in South America. Pleistocene of North America. Bell and others (2004) indicate that Stegomastodon is limited to the Blancan *eVicugna (Artiodactyla: Camelidae). This endemic camel is (ca. 3.5 Ma) and Irvingtonian (ca. 1.2 Ma) in North shown as Ensenadan to Recent in M&B 00, is listed as America. Ensenadan in Vrba (1993), and included within Lama in Marshall and others (1983) and Cione and Tonni *Cuvieronius (Proboscidea: Gomphotheriidae). Marshall (2005). and others (1983) report this genus from the Uquían to Lujanian. It is not listed in Tonni and others (1992) or *Palaeolama (Artiodactyla: Camelidae). This genus is Cione and Tonni (1995) from the Marplatan = Uquían. recorded in Inglis IC Fauna of Florida, correlated to Cuvieronius is not present in Argentina. Alberdi and about 1.8 Ma (Bell et al., 2004; Morgan, 2005). The Prado (1995) report it from the late Pliocene or early genus ranges from the Ensenadan to Lujanian (Cione Pleistocene to late Pleistocene. Here it is listed as and Tonni, 1995). It is not present in the Marplatan, Ensenadan to Lujanian (see MacFadden, 2000). This contra Marshall and others (1983). Nevertheless, genus is recorded in late Hemphillian/early Blancan Morgan (2005) noted Paleolama as a native North faunas of North America, ca. 4.9 Ma in age (Pañaca; American genus. At this time it appears that the Bell et al., 2004), 3.0–3.6 Ma (Camp Rice Fm., New northern and southern first occurrences might be Mexico), as well as late Blancan sites in Arizona, coeval at the level of resolution available. In any case Florida and Texas (Lambert and Shoshani, 1998). It it is an immigrant to South America. also occurs in late Pleistocene sites in Honduras, Costa Rica and Mexico (Lucas et al., 1997; Jackson and *eEpieuryceros (Artiodactyla, Cervidae). Churcher (1966) Fernández, 2005). considers Epieuryceros as a junior synonym of Blastoceros (see also M&B 00). However, Bagnalasta Irvingtonian, ca. 1.8–0.25 Ma (1980) validates Epieuryceros as a distinct genus. It is exclusive to the Ensenadan (Cione and Tonni, 2005). Didelphis (Marsupialia: Didelphidae). Vrba (1993) lists this It represents the first record of the Cervidae in South didelphid immigrant as early Irvingtonian. Bell and America. others (2004) show an Irvingtonian and Rancholabrean

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to Recent range for Didelphis and indicate (p. 282) that Pecari tajacu (= Dicotyles; Woodburne, 1969) first the genus first occurs in early Irvingtonian faunas, such occurs in the Megatherium americanum biozone, or as Fyllan Cave, Texas, with a likely age of 0.78–1.77 Bonaerian SALMA, or about 0.6 Ma. Ma. Table 1 shows a correlated age of about 1.2 Ma. *Morenelephus (Artiodactyla: Cervidae). Morenelephus is Nothrotheriops (Xenarthra: Megatheriidae). Vrba (1993) known from the Bonaerian Cione and Tonni (2005). lists this member of an otherwise South American Webb and Rancy (1996) indicate that this name megathere as early Irvingtonian, but Bell and others includes Hippocamelus of previous literature, but (2004) indicate a latest Blancan age. Lundelius Adriana Menegaz (2005, personal communication) and others (1987) cite an age of about 2.1 Ma notes that this is not the case. for Nothrotheriops in the Vallecito Creek L.F. of California, corroborated by Bell and others (2004, Lujanian, ca. 0.125–0.08 Ma fig. 7.2). Morgan (2005) suggests that this record is of Megalonyx, so the earliest record of Nothrotheriops is This follows Cione and Tonni (1995). Cione and Tonni (2001, ca. 1.4–1.6 Ma (Leisey Shell Pit, Florida). 2005) separate Bonaerian from Lujanian, with Lujanian being late Pleistocene. Myrmecophaga (Xenarthra: Myrmecophagidae). The sole occurrence of this genus is in the El Golfo Fauna *Lutra (Carnivora: Mustelidae). The genus is immigrant in of Sonora (Bell et al., 2004). The association of the Ensenadan according to Vrba (1993) and extends Megalonyx wheatleyi in this fauna suggests an age of to the Recent (Marshall et al., 1983; M&B 00). about 1.0 Ma based on typical occurrences of that sloth The first record of this genus in Argentina is in late elsewhere in North America. Lujanian beds of Buenos Aires Province, Argentina (Tonni et al., 1985). Other records of the genus are in Bonaerian, ca. 0.7–0.125 Ma the early Pliocene of Europe and Asia. Tedford and others (2004) list the genus from the late Hemphillian *eParaceros (Artiodactyla: Cervidae). Paraceros was (Hh4) of North America. Lontra is a synonym of Lutra considered a synonym of Habromeryx (Cabrera, 1929) according to McKenna and Bell (1998). and M&B 00 indicate that Habromeryx is a junior synonym of Morenelaphus. However it is presently *ePteronura (Carnivora: Mustelidae). This endemic South considered a junior synonym of Paraceros (see American genus of a Holarctic family occurs in Ubilla and Perea, 1999; Cione and Tonni, 1999). It is Lujanian beds of Entre Ríos Province, Argentina (see known from the Bonaerian of Buenos Aires Province, Carlini et al., 2002). Argentina (Cione and Tonni, 1999, 2005). *Nasua (Brachynasua) (Carnivora: Procyonidae). Marshall *eArctotherium (Carnivora: Ursidae). The tremarctines and others (1983) record this immigrant genus as Arctotherium vetustum, A. bonariense and A. tarijense Lujanian and ?Ensenadan to Recent. M&B 00 suggest occur in the Bonaerian (Soibelzon et al., 2005), it is known from the early Pleistocene (= Ensenadan). according to whom the genus does not occur in North Vrba (1993) lists it as Ensenadan. M&B 00 list America. Brachynasua as possibly from the early and middle Pleistocene of South America. The genus is not present *eHerpailurus (Carnivora: Felidae). A probable specimen of in southern South America (Cione and Tonni, 1995). this genus comes from Bajo San José, southern Buenos Aires Province, Argentina (Prevosti, in press). Eira (Carnivora: Mustelidae). This genus is restricted to the Pleistocene according to M&B 00. Marshall and others *Pecari (Artiodactyla: Tayassuidae). This peccary ranges (1983) list the genus as Lujanian to Recent. from Lujanian to Recent in Marshall and others (1983), with an ?Ensenadan record. It begins in the Ensenadan *eDusicyon (Carnivora, Canidae). See comments on Dusicyon per Vrba (1993). Cione and Tonni (2005) indicate that under the Marplatan.

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*eOncifelis and Leopardus (Carnivora: Felidae). These South communication). Lundelius and others (1987) note American genera are known from late Lujanian beds the genus is present in late Hemphillian (Hh 3, ca. 5 of the Buenos Aires Province, Argentina (Prevosti, in Ma) and younger faunas of North America. See also press). Munthe (1998). Carranza-Castañeda and Miller (2004) list Canis from late Hemphillian faunas of Mexico, but *eOryzomys (Rodentia, Sigmodontinae). The range is some of these (Guanajuato) are likely early Blancan ?Pleistocene to Recent of South America according to (ca. 4.8 Ma). M&B 00. It is apparently not found in the Marplatan; not listed in Cione and Tonni (1995). Tonni and others *Equus (Perissodactyla: Equidae). This immigrant equid (1992) show Recent only. Vrba (1993) lists the genus is listed as Ensenadan to Lujanian in Marshall and as early Chapadmalalan. This is an endemic genus. others (1983) and M&B 00. Cione and Tonni (2001, 2005) indicate that equids first occur in the Vorhuean, *eEuneomys (Rodentia, Sigmodontinae). M&B 00 cite or about 2.7 Ma. Equus is recorded in the Lujanian Marshall and others (1983) for a Lujanian occurrence in southern South America (sensu Cione and Tonni, of this endemic genus. Vrba (1993) indicates an 1999, 2005). Specimens of Equus occur in Bolivia “Uquían” age. Tonni and others (1992) and Cione and in levels assigned to the Ensenadan (MacFadden et Tonni (1995) do not list this genus. al., 1983). However, the stratigraphic level with the specimens, of normal magnetostratigraphic polarity, *eHippocamelus (Artiodactyla: Cervidae). M&B 00 suggest does not include typical Ensenadan taxa. Alberdi and the most likely age is Lujanian to Recent, as Tonni Prado (1995: 299) mention the same species in the and others (1992) also consider. Vrba (1993) lists this middle Pleistocene beds in the Río Chiche. However, endemic genus as “Uquían.” Webb and Rancy (1996) these beds are currently assigned to the late Pleistocene offer that this taxon is misidentified, and should be (Hoffstetter, 1986). Morenelephus. Homo (Primates: Hominidae). Man entered South America *eOzotoceros (Artiodactyla: Cervidae). Cioni and Tonni and in the latest Lujanian. others (2005) indicate a Lujanian to Recent age. M&B 00 are inconclusive except for a Recent age. Vrba (1993) Recent lists the endemic taxon as “Uquían,” which is an error. Several immigrants do not have a fossil record. Some of Sylvilagus (Lagomorpha: Leporidae. This immigrant rabbit them are actively expanding their geographic ranges. entered South America in the Lujanian. Cryptotis (Soricomorpha: Sorididae). *Canis (Carnivora: Canidae). The first certain record of Canis in South America is C. dirus in indeterminate Heteromys (Rodentia: Heteromyidae). Pleistocene beds from the northern part of the continent (Berta, 1987). In southern South America, the first Orthogeomys (Rodentia: Geomyidae). known definitive Canis entered with Homo sapiens in the latest Lujanian. Another species, C. nehringi, Microsciurus (Rodentia: Sciuridae). known from indeterminate levels of latest Lujanian to Platan age in northeastern Buenos Aires Province, Sciurillus (Rodentia: Sciuridae). Argentina (Kraglievich, 1928), appears to be a junior synonym of C. dirus (Francisco Prevosti, personal Sciurus (Rodentia: Sciuridae).

Carranza-Castañeda, Óscar, and Lindsay, E.H. eds., Advances in late Tertiary vertebrate paleontology in Mexico 2006