TWO NEW RECORDS OF GOMPHOTHERIIDAE (MAMMALIA: PROBOSCIDEA) IN SOUTHERN MÉXICO AND SOME BIOGEOGRAPHIC IMPLICATIONS

BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors nonprofit publishers academic institutions researchlibraries and research funders in the common goal of maximizing access to critical research

TWO NEW RECORDS OF GOMPHOTHERIIDAE (MAMMALIAPROBOSCIDEA) IN SOUTHERN MEacuteXICO AND SOME BIOGEOGRAPHICIMPLICATIONSAuthor(s) EDUARDO CORONA-M and MARIacuteA TERESA ALBERDISource Journal of Paleontology 80(2)357-366 2006Published By The Paleontological SocietyDOI httpdxdoiorg1016660022-3360(2006)080[0357TNROGM]20CO2URL httpwwwbiooneorgdoifull1016660022-3360282006290805B03573ATNROGM5D20CO3B2

BioOne (wwwbiooneorg) is a nonprofit online aggregation of core research in the biological ecological andenvironmental sciences BioOne provides a sustainable online platform for over 170 journals and books publishedby nonprofit societies associations museums institutions and presses

Your use of this PDF the BioOne Web site and all posted and associated content indicates your acceptance ofBioOnersquos Terms of Use available at wwwbiooneorgpageterms_of_use

Usage of BioOne content is strictly limited to personal educational and non-commercial use Commercial inquiriesor rights and permissions requests should be directed to the individual publisher as copyright holder

357

J Paleont 80(2) 2006 pp 357ndash366Copyright q 2006 The Paleontological Society0022-3360060080-357$0300

TWO NEW RECORDS OF GOMPHOTHERIIDAE(MAMMALIA PROBOSCIDEA) IN SOUTHERN MEXICO

AND SOME BIOGEOGRAPHIC IMPLICATIONSEDUARDO CORONA-M1 AND MARIA TERESA ALBERDI2

1Laboratorio de Arqueozoologıa Instituto Nacional de Antropologıa e Historia Moneda 16 Col Centro 06060 Distrito Federal Mexicoecoromacorreounammx and 2Departamento de Paleobiologıa Museo Nacional de Ciencias Naturales CSIC Jose Gutierrez Abascal 2

28006 Madrid Espana malberdimncncsices

ABSTRACTmdashTwo new records of gomphotheriid proboscideans one identified as Rhynchotherium and the other as Cuvieronius arereported in Mexico Both records are in the southwesternmost points of their known distributional range

The remains of both genera consist of molars and tusks Their measurements were compared with data available from the literatureand collection specimens The molar index of Rhynchotherium shows statistical differences between m2 and M2 and m3 and M3However differences between the m3 from both genera are not statistically significant despite slight morphological differences

This suggests that metric and morphological information should be included for a reliable identification of isolated molars and ifavailable any other data of the associated tusk

All known records relating to both genera suggest that they found southwestern Mexico favorable for use as a dispersal corridor toSouth America likely due to the regionrsquos tropical or subtropical climate However some distributional gaps in central Mexico need tobe resolved for Rhynchotherium There are also important populations of Cuvieronius in central Mexico and preliminary informationsuggests that they occupied at least parts of eastern Mexico as well

INTRODUCTION

THE FAMILY Gomphotheriidae is an ancestral group of probos-cideans that are considered to have been chronologically and

biogeographically successful (Tobien 1973 Lambert 1996)North America was an important region for their diversificationand geographical dispersal to South America In North Americaspecimens representing this family are recorded from the middleMiocene to late Pleistocene (Kurten and Anderson 1980 Lam-bert 1996) Their highest level of diversity was from the lateBarstovian to the early Hemphillian during which time six generawere recorded Gomphotherium Burmeister 1837 Rhynchother-ium Falconer 1868 [in Central America see Webb and Perrigo(1984)] Amebelodon Barbour 1927 Platybelodon Borissiak1928 Torynobelodon Barbour 1929 and Serbelodon Frick 1933During the late Hemphillian only three genera have been record-ed Gomphotherium Rhynchotherium and Amebelodon In theBlancan the genera recorded are Rhynchotherium Stegomasto-don Pohlig 1912 and Cuvieronius Osborn 1923 While Rhyn-chotherium became extinct in the Late Blancan Stegomastodonsurvived until the Irvingtonian and Cuvieronius until the Ran-cholabrean (Lambert 1996)

Specimens of gomphotheriids currently assigned to Cuvieron-ius were recorded in Mexico during the nineteenth century byCope (1884 1886) Felix and Lenk (1891) and somewhat laterby Freudenberg (1922) Afterward many of these records wereincorporated in an exhaustive review of the family written byOsborn (1936) However it can be shown that many of thesespecies were named based on the characteristics of isolated mo-lars Recently their status was reviewed by Kurten and Anderson(1980) and Shoshani (1996)

In Mexico remains of gomphotheriids are scarce and oftenlimited to isolated molars and tusks the majority of which werenot recovered from systematic excavations Additionally in a ma-jority of these localities there is no clear stratigraphy RecentlyMiller and Carranza-Castaneda (2002) reviewed the Tertiary lo-calities in Mexico correlating some of them with available dataof their research in central Mexico Nevertheless in the last 20years the record of this family has increased with the report oftwo new findings of the genus Cuvieronius one from Sonora(Lucas and Gonzalez-Leon 1997) and the other from Puebla

(Montellano-Ballesteros 2002) We are also aware of other pre-liminary records that have been identified as Cuvieronius One ofthese is from Chiapas (Carbot and Montellano-Ballesteros 2002)and the other from Yucatan (Polaco et al 2002) We expect fullyreported results of these records in the near future

The objectives of this paper are to detail the two new gom-photheriid localities in Mexico and to describe and provide mea-surements of the material recovered from these localities com-paring with data available from the literature and with specimensfrom Mexican localities In addition the biogeographic implica-tions for both genera are also discussed

LOCALITIES

San Juan Union Taxco GuerreroThe town is approximate-ly 20 km south of the city of Taxco de Alarcon in the state ofGuerrero The excavation site was 1 km north of the town geo-graphically positioned at 188389N 998389W and at 1400 masl(Corona-M et al 1999) (Fig 1)

The locality was located at the confluence of two slopes at thebase of a hill where an artificial pond had been constructed Thefaunal remains were recovered from layers of clay and silt thatwere laden with cobbles and pebbles No other remains associatedwith gomphotheriids either synchronic or diachronic were foundThese combined factors indicate that the remains were a rede-position probably by a shallow debris flow from the highest zoneof the hill to lower zones The gomphotheriid remains had surfacecracks indicative of weathering These marks suggest that the re-mains were frequently covered and uncovered and that this pro-cess probably occurred over a long period of time

Nexpa Tlalquitenango MorelosThis town is located ap-proximately 40 km southeast of the city of Cuernavaca The lo-cality is at the edge of the town on a dirt road constructed downthe slope of a nearby hill that led to the Cuautla River The erosionproduced by the traffic and the rain discovered part of the re-mains and somewhat later was excavated (Corona-M et al2000) The geographic position of this locality was 188319N998089W and 810 masl (Fig 1)

The remains were located in a layer of white clay with cobblesand pebbles The underlying layer is thick and compact and

358 JOURNAL OF PALEONTOLOGY V 80 NO 2 2006

FIGURE 1mdashMap of Mexico showing both localities studied 1 San Juan Union Taxco Guerrero 2 Nexpa Morelos

formed of calcareous sand These features suggest that as at Tax-co a redeposition occurred from higher to lower layers The fau-nal remains were the only materials yielded and they also hadmarks indicative of intensive weathering

MATERIAL AND METHODS

Identification of this material to the genus level follows thediagnostic criteria established by Tobien (1973) and Lambert(1996) We do not identify species because like Kurten and An-derson (1980) Lambert (1996) and Shoshani (1996) we believethat further taxonomic reviews of these taxa are necessary in orderto clarify their current status

The following measurements and observations were taken ontusks maximum length (taken along the curvature) maximumand minimum basal diameters and maximum and minimum me-dial diameters (taken at the midpoint of the tusk length) It mustbe noted that only maximum diameter measurements could beobtained from the Cuvieronius tusks given that they were almostcompletely rounded In addition if the tusk bore an enamel bandits presence width and shape were recorded

Measurements and observations of molars were made follow-ing Alberdi et al (2002) (Fig 2) length width of the loph(id)sand a morphological description of the medial sulcus cingulacentral conules the presence or absence of cement and trefoilsTrefoils refer to the pattern of wear on the occlusal surface of thetooth and denote the part of each half of the loph(id) that formsthe main cusp and central conules Pretrite refer to each halfloph(id) which is more worn lingual on the upper molars andlabial on the lower teeth All measurements are in millimetersThe mandibular teeth are indicated by the lower case (m) whilemaxillary teeth are indicated by the upper case (M)

In addition an index was calculated for each molar followingthe formula maximum width 3 100length This index is usedby Osborn (1936) and currently known as the molar crown index(Hillson 1986) The Mann-Whitney U test was applied in orderto find significant differences among these values This test is veryuseful in comparing the medians of small samples

In the case of Rhynchotherium the data were compared withavailable measurements found in the literature such as Osborn(1936 p 483) and Miller (1990) Furthermore measurementswere acquired from both the specimen reported by Carranza-Cas-taneda (1976) from Rancho La Goleta Michoacan and one iso-lated molar from the same locality In the case of Cuvieronius thedata were compared with molar specimens from TequixquiacMexico and Acultzingo Puebla All the aforementioned speci-mens are housed in the Collection of the Instituto de GeologıaUniversidad Nacional Autonoma de Mexico Specimen measure-ments were taken by MTA following the procedures mentionedabove

The material recovered from the San Juan Union locality in-cludes eight molars presumably from a single individual left andright m2 and m3 left and right M2 and M3 left and right man-dibular tusks and fragments of the left and right mandibular rami

The Nexpa locality yielded one maxillary tusk reconstructedfrom three major fragments and one left m3

SYSTEMATIC PALEONTOLOGY

All materials are deposited in the Coleccion Paleontologica delLaboratorio de Arqueozoologıa at the Instituto Nacional de An-tropologıa e Historia (acronym DP)

359CORONA-M AND ALBERDImdashNEW GOMPHOTHERIIDAE FROM SOUTHERN MEXICO

FIGURE 2mdashSketch of the m3 of a gomphothere occlusal view showingmeasurements and morphological descriptions L 5 length W 5 max-imum width of each loph(id) 1ndash4 T 5 Talon (id) ci 5 cingulum im e 5 internal medial and external cusps c 5 central conulesdashed line 5 median sulcus The pretrite refer to each half loph(id)which is more worn see text for details Modified from Alberdi et al2002

Family GOMPHOTHERIIDAE Cabrera 1929Genus RHYNCHOTHERIUM Falconer 1868

DiagnosisMandible rami stout and mandible symphysis an-gled downward Inferior tusk compressed laterally and externalenamel band present Enamel band is also present laterally onsuperior tusk Short molars with single or slightly complex pretritetrefoils enamel thick (Tobien 1973 Kurten and Anderson 1980)

Material examinedFrom the San Juan Union locality Guer-rero Left mandibular tusk (DP-5769) Maximum length 630 bas-al diameters maximum 51 minimum 462 medial diametersmaximum 62 minimum 517 (Fig 31) Right mandibular tusk(DP-5768) Maximum length 690 basal diameters maximum65 minimum 49 medial diameters maximum 558 minimum47 (Fig 32) Both tusks slightly curved with scarce traces ofenamel bands surely mostly absent due to wear and weathering

Main measurements of the molars and index values are givenin Table 1

Left m2 (DP-5775) three lophids median sulcus central con-ules and trefoils obliterated through wear cingulum observablecement perceptible (Fig 41)

Right m2 (DP-5774) three lophids first broken median sulcuscentral conules and trefoils obliterated through wear cingulumobservable and broken in part cement perceptible (Fig 42)

Left M2 (DP-5771) three lophs and strong talon median sul-cus central conules and trefoils extremely worn cingulum notapparent cement perceptible (Fig 43)

Right M2 (DP-5770) three lophs and small talon median sul-cus central conules and trefoils worn cingulum observable ce-ment not perceptible (Fig 44)

Left m3 (DP-5777) four lophids and strong talonid mediansulcus observable central conules with binary division and slightwear trefoils observable cingulum visible between the third lo-phid and talonid central conules present cement perceptible (Fig45)

Right m3 (DP-5776) four lophids and talonid strong mediansulcus observable central conules with binary division and slightwear trefoils observable and moderate wear cingulum observ-able cement present (Fig 46)

Left M3 (DP-5772) four lophs and strong talon median sulcusobservable central conules observable and main external cone ofloph 2 with ternary division trefoils observable with moderatewear cingulum observable cement perceptible (Fig 47)

Right M3 (DP-5773) four lophs and strong talon median sul-cus observable central conules observable except internal coneof loph 1 and loph 2 broken presumably by weathering mainexternal cone of loph 2 with ternary division trefoils slightlydeveloped cingulum observable in part cement perceptible (Fig48)

OccurrenceFor many authors this genus is autochthonousfrom America and defines the late Hemphillian faunas (Tedfordet al 1987) However Webb and Perrigo (1984) postulate a Cen-tral American radiation from the early Clarendonian to the earlyHemphillian and a reverse dispersal to the north Neverthelesswe consider that this latter hypothesis needs further study andadditional substantiating data Finally Lambert (1996) consideredthis genus to be characteristic of the late Hemphillian to Blancan

The genus Rhynchotherium was previously recorded from thewell-known late Hemphillian fauna localities at El Ocote in theState of Guanajuato and from Blancan faunas at La Goleta in theState of Michoacan and Santa Anita (Las Tunas) in the State ofBaja California (Carranza-Castaneda 1976 Dalquest and Mooser1980 Miller 1980 Miller and Carranza-Castaneda 1984 2002)In the case of San Juan Union locality unfortunately the strati-graphic data do not enable precise chronological placement andtherefore we refer this material only as late as Miocene to Plio-cene based on the known stratigraphic distribution of Rhynchoth-erium

Geographic distributionIn North America this genus wasrecorded from eastern California to Florida and from southernKansas southward through Mexico to Central America (Lambert1996) In Mexico this genus is known to be distributed in thenorthwest and west-central portions of the country The San JuanUnion record is the most southwestern locality known in MexicoOther localities where this genus has been reported include So-nora San Jose Pimas (Osborn 1921 1936) and Minas Prietas(Frick 1933) and Tlaxcala an unspecified locality (Falconer1868 Osborn 1936) (Table 2 Fig 6)

The specific names of the genus Rhynchotherium have a com-plex history because only three species in Mexico have beennamed The holotype is the specimen identified as R tlascalae(Falconer 1868) from an undetermined locality in the State ofTlaxcala and rediscovered by Osborn (1936) However no otherspecimen has been recovered from this area One specimen wasrecovered from San Jose Pimas Sonora which at first was pro-posed as a neotype of R tlascalae but was later named R browni(Osborn 1936 p 494) The third species was nominated R fal-coneri (Osborn 1923) from a specimen recovered in Llano Es-tacado (Mt Blanco) Texas This last name has predominated inmost of the reports of this genus As we pointed out earlier further


FIGURE 3mdashMandibular tusks of Rhynchotherium Falconer 1868 in lateral view 1 Left tusk (DP-5769) 2 right tusk (DP-5768) Scale bar 5 20 cm


TABLE 1mdashMeasurements of molar teeth of Rhynchotherium and Cuvieronius following Alberdi et al (2002) In the source column for each molar specimeneither the collection number or the reference where the metric data were obtained is indicated In the tooth column the letter beside the molar indicates theposition (L left R right) () indicates the identification provided in the reference Other columns L 5 length W(1-2-3-4-5 and T) 5 width of eachloph(id) or talon(id) MW 5 maximum width

Source Locality

IdentificationRhynchotherium

specimens Tooth L W1 W2 W3 W4 WTalon MW Index

DP-5770 Taxco Guerrero R M2 112 78 819 798 819 731DP-5771 Taxco Guerrero L M2 1108 771 83 831 831 750DP-5772 Taxco Guerrero R M3 153 825 81 76 70 43 825 539DP-5773 Taxco Guerrero L M3 1615 79 73 412 79 489DP-5774 Taxco Guerrero R m2 114 73 80 80 702DP-5775 Taxco Guerrero L m2 116 64 73 797 797 687DP-5776 Taxco Guerrero R m3 176 76 74 80 74 52 80 455DP-5777 Taxco Guerrero L m3 178 72 75 78 76 52 78 438IGCU-874 La Goleta Michoacan R cf R falconeri R M2 109 74 83 76 83 761IGCU-874 La Goleta Michoacan R cf R falconeri R M3 143 85 83 73 575 85 594IGCU-874 La Goleta Michoacan R cf R falconeri R m2 122 68 745 752 752 616IGCU-874 La Goleta Michoacan R cf R falconeri L m2 1152 695 76 75 76 660IGCU-874 La Goleta Michoacan R cf R falconeri R m3 1555 795 82 80 82 527IGCU-874 La Goleta Michoacan R cf R falconeri L m3 1585 785 84 81 64 84 530IGM 491 La Goleta Michoacan R cf R falconeri R m3 165 681 75 725 598 75 455Miller 1990 Arizona USA R cf R falconeri R M2 123 83 675Miller 1990 Arizona USA R cf R falconeri L M2 122 82 672Miller 1990 Arizona USA R cf R falconeri R M3 160 89 556Miller 1990 Arizona USA R cf R falconeri L M3 162 87 537Miller 1990 Arizona USA R cf R falconeri R m2 125 73 584Miller 1990 Arizona USA R cf R falconeri L m2 121 75 620Miller 1990 Arizona USA R cf R falconeri R m3 173 83 480Miller 1990 Arizona USA R cf R falconeri L m3 172 86 500Osborn 1936 S J Pimas Sonora R browni R m2 136 100 735Osborn 1936 S J Pimas Sonora R browni R m3 176 96 545Osborn 1936 S J Pimas Sonora R browni L m3 180 96 533Osborn 1936 Llano Estacado Texas R falconeri R m2 133 77 579Osborn 1936 Llano Estacado Texas R falconeri L m2 131 79 603Osborn 1936 Llano Estacado Texas R falconeri R m3 173 80 462Osborn 1936 Llano Estacado Texas R falconeri L m3 168 80 476Osborn 1936 Tlaxcala R tlascalae L m3 180 99 550

Acronym Locality

Cuvieroniusspecimens

Identification Tooth L W1 W2 W3 W4 W5 WTalon MW Index

IGM4007 Tequixquiac Mexico C oligobunis R m3 199 78 92 92 80 92 4623IGM4007 Tequixquiac Mexico C oligobunis L m3 201 80 79 95 78 44 95 4726DP-5779 Nexpa Morelos L m3 178 69 47 69 3876MGUNAM237 Acultzingo Puebla C oligobunis L m3 1855 734 79 833 713 454 833 4491

systematic revision for this genus is necessary because there donot appear to be important differences between these species ei-ther morphological or metrical (Table 1)

Genus CUVIERONIUS Osborn 1923

DiagnosisThis genus is brevirostrine and differs from Rhyn-chotherium by the absence of inferior tusks Superior tusks havea spiral enamel band Molars have a slight alternation of the half-loph(id)s or anancoidy and also possess a great deal of morpho-logical variation on the pretrite trefoils from single to poorlydeveloped The third molars possess four-and-a-half to five-and-a-half loph(id)s (Kurten and Anderson 1980 Lambert 1996)

Material examinedFrom Nexpa Morelos A curved superiortusk with a spiral enamel band (DP-5778) Maximum length1018 maximum basal diameter 873 maximum medial diame-ter 709 width of enamel band 229 (Fig 5)

Left m3 (DP-5779) this fragmented tooth is heavily damagedby weathering but four lophids and a strong talonid can be ob-served median sulcus absent central conules and trefoils ex-tremely worn cingulum observable but partly broken The onlymeasurements available are length 178 and width of loph 4 69Note that this molar is the smallest in the sample but this isbecause the only measurement available is from the fourth lophid(Fig 7)

OccurrenceThis endemic genus of the New World first ap-peared in the Blancan and was present until the late Ranchola-brean It may have dispersed into South America in the late Blan-can to early Irvingtonian (Kurten and Anderson 1980 Lambert1996) However we agree with Montellano-Ballesteros (2002)that most of the Mexican localities do not have precise strati-graphic information and the records can be assigned by corre-lation only to the PliondashPleistocene

Geographical distributionThe genus Cuvieronius has beenrecorded in southern North American localities in Arizona NewMexico Texas and Florida (Lambert 1996) The genus occupiedan area in Mexico that included the northwestern-to-central andsoutheastern portions of the country This is the first record forthe state of Morelos Other localities have been reported in thestates of Sonora Chihuahua Jalisco Michoacan Mexico DistritoFederal Hidalgo Guerrero Puebla Oaxaca and Chiapas includ-ing the localities mentioned in the introduction (see Table 2 Fig6) For an overview of the systematics of this genus refer toMontellano-Ballesteros (2002)

DISCUSSION

We found clear differences among molars within Rhynchoth-erium On second molars the mandibular teeth are significantlylonger and narrower than the maxillary teeth (U 5 7 P 5 0039)


FIGURE 4mdashMolar teeth of Rhynchotherium 1 Left m2 (DP-5775) 2 right m2 (DP-5774) 3 left M2 (DP-5771) 4 right M2 (DP-5770) 5 left m3(DP-5777) 6 right m3 (DP-5776) 7 left M3 (DP-5772) 8 right M3 (DP-5773)

In third molars the differences also are significant (U 5 10 P 50035) where the maxillary teeth are shorter than the mandibularteeth but longer than the second molars (Fig 7) It should bepointed out that one m2 from an Osborn specimen is unusuallywide (100 mm) but the variability among the other specimens inthe analyzed sample could be related to sexual dimorphism ageor geographical variation (Fig 7) However further research isnecessary to explain these details

The mandibular third molars of Rhynchotherium and Cuvieron-ius are only slightly different Rhynchotherium molars are shorterand wider which makes them appear more homogeneous How-ever in Figure 7 the metric data show the great variability in sizeand the morphological similarity of the third molars of these gom-photheriids and in fact the statistical test fails to separate them(U 5 9 P 5 069) This similarity between the molars of bothgenera could be a result of phylogenetic proximity or be due tothe fact that they occupied similar habitats

In the specimen reported here the trefoils another diagnosticcharacter were not useful in identifying the specimens because

the Cuvieronius material was extremely worn and had only onecomplete lophid It was the presence of associated tusks amongour molar specimens that permitted us to identify positively theremains These identifications were based on the inferior tusks inthe case of Rhynchotherium and the superior tusks with a spiralenamel band in the case of Cuvieronius

The results shown herein suggest that the identification of iso-lated molars is an intricate task given that the index obtainedfrom molars is not an adequate metric criterion In addition theocclusal wear of the teeth is not a sufficiently informative differ-entiating character It is clear that a detailed comparative study isneeded on molar variation within gomphotheriid mastodonts Atthe moment we believe that in order to make a reliable identifi-cation of a gomphotheriid molar to the genus level both metricand morphological characters of complete molars should be usedas well as any available information on associated tusks

The available geographical information suggests that Rhyncho-therium used southwestern Mexico as a corridor made possible bythe warm and humid savanna-like environmental conditions such


TABLE 2mdashKnown localities of Rhynchotherium and Cuvieronius in Mexico The column symbol (S) refers to its position in Figure 6 (x) 5 Undeterminedlocalities not shown in map Source column indicates the latest known reference see text for other references

S

Rhynchotherium

Locality State Source

A Minas Prietas Sonora Frick 1933B San Jose Pimas Sonora Osborn 1936C Santa Ana Baja California Sur Miller 1980D El Ocote Guanajuato Miller and Carranza-Castaneda 1984E La Goleta Michocan Carranza-Castaneda 1976F Undetermined Tlaxcala Osborn 1936G Taxco Guerrero herein

S

Cuvieronius


1 El Golfo Sta Clara Sonora Shaw 19812 Oquitoa Sonora Lucas and Gonzalez-Leon 19973 Ciudad Guerrero Chihuahua Eaton 19054 Real del Monte Hidalgo Freudenberg 19225 Apaxco de Ocampo Mexico Cope 18846 Tequixquiac Mexico Freudenberg 19227 Ixtapantongo Mexico Pichardo del Barrio 19608 Almoloya Mexico del Castillo 18699 Quetepec Mexico Freudenberg 1922x Valle de Mexico Mexico Freudenberg 1922x Valle de Toluca Mexico Cope 1884x Undetermined Michoacan Von Meyer 1840

10 Chichihualco Guerrero Freudenberg 192211 Nexpa Morelos herein12 Rancho Gerardo Puebla Montellano-Ballesteros 200213 Tecamachalco Puebla Felix and Lenk 189114 Tehuacan Puebla Pichardo del Barrio 196015 Acultzingo Puebla Freudenberg 192216 Huajuapan de Leon Oaxaca Freudenberg 192217 Tlaxiaco Oaxaca Felix and Lenk 189118 Cosoltepec Oaxaca Ochoterena and Silva-Barcena 197019 Chiapa de Corzo Chiapas Carbot and Montellano-Ballesteros 200220 Villa de Corzo Chiapas Boese 1905x Undetermined Chiapas Osborn 193621 Cenote Nai Tucha Yucatan Polaco et al 2002

FIGURE 5mdashDetail of the maxillary tusk of Cuvieronius Osborn 1923 in lateral view (DP-5778) showing enamel band Scale bar 5 10 cm

as were detected for the localities of Santa Anita La Goleta andRancho El Ocote (Miller and Carranza-Castaneda 1984) Theseenvironmental conditions can be extended and applied at the ad-jacent Taxco area as well (Fig 6 Table 2)

While all the previously mentioned localities could comprisea single distributional range in western Mexico the indetermi-nate locality of Tlaxcala appears to be an isolated point outsideof this range (Fig 6) It is necessary then to confirm this localityand clarify the presence of Rhynchotherium in this geographicalgap in order to ascertain if it inhabited central Mexico and todetermine the southwesternmost part occupied as their dispersalcorridor to Central America This information will shed newlight on the rather weakly supported hypothesis of Webb and

Perrigo (1984) Nevertheless until further research is done inthese geographical areas we do not completely rule out this hy-pothesis

The geographical dispersion of Cuvieronius across Mexicothrough the southwest Mexican corridor and into Central Americais much clearer now due to records of this genus in the Chiapasarea In addition there is also evidence pointing to the presenceof important populations of Cuvieronius in both western and cen-tral Mexico (Fig 6) The distribution range of this taxon will beextended if their presence is confirmed in the state of YucatanTheir presence in the Yucatan Peninsula would mean that thegenus also inhabited tropical habitats of eastern Mexico andwould clarify the connection with the records from Florida


FIGURE 6mdashApproximate location of the known records in Mexico of Rhynchotherium (letters) and Cuvieronius (numbers) including localities reportedherein See Table 2 for details

FIGURE 7mdashBivariate diagram of length versus maximum width frommeasurements in Table 1 m2 M2 m3 and M3 for Rhynchotheriumspecimens m3-C for Cuvieronius specimens

These data suggest that gomphotheriids inhabited mainly sub-tropical or tropical lowlands habitats (Dudley 1996) The recentevidence provided by Sanchez et al (2004) confirms that differentfeeding preferences were the main reason that bunodont gom-photheriids reached South America Thus early Cuvieronius andStegomastodon apparently entered that area during the early ormiddle Pleistocene at the time of a more arid glacial phase whensavanna habitats extended broadly through tropical latitudes Themost likely explanation for the absence of other proboscideanssuch as Mammut Blumenbach 1799 and Mammuthus Burnett1829 in South America is that these taxa were highly specializedfeeders preferring habitats not found in the Panamanian landbridge (Sanchez et al 2004)

This data would be of particular interest in light of the refine-ments that have been made in the chronology of the Great Amer-ican Faunal Interchange in recent years Today it is clear that theearliest record of Cuvieronius in South America was in the middlePleistocene of Tarija Bolivia (Alberdi et al 2002 Prado et al2003) This locality has been dated between 107 to 07ndash06 Ma(MacFadden 2000) It will be important in the near future toimprove the biochronological quality of the vertebrate paleonto-logical record in southern Mexico in order to construct a clearerpicture of the dispersal corridors used by this taxa

CONCLUSIONS

Two new localities in Mexico with gomphotheriid remains weredescribed One locality in Morelos represents the first record of


Cuvieronius in that state The other locality from the state ofGuerrero contains remains of Rhynchotherium that record at thesouthernmost point of its known distribution range in Mexico

We did not find statistical differences between the two generaon the basis of third molar a fact that could be related to phy-logenetic proximity Further studies on molar variability are nec-essary in order to evaluate variations due to sexual dimorphismage or geographical variation At the present time we considerthat a reliable identification to the genus level can be made onthe basis of morphological and metric characters as well as onthe characteristics of the tusks if available

These new records improve our knowledge of the zoogeogra-phy of this taxonomic group but certainly two types of additionalstudies are needed One should focus on analyzing diagnosticcharacters and the local and continental variability of each genusmainly with respect to molars and tusks as they are the mostcommon remains Another study should be aimed at improvingthe biochronology of the Mexican localities in order to integratethem more fully with available data from the American FaunalInterchange between North and South America

ACKNOWLEDGMENTS

To M C Perilliat for the authorization to study specimens inthe collection of the Instituto de Geologıa UNAM To J Saun-ders E Scott and two anonymous reviewers their comments andsuggestions were very helpful and improved the original manu-script To L Garcıa E Pina M T Montes E Jimenez GarcıaJ A Quiroz Moreno and S Analco for their animated collabo-ration in field work To local authorities from Nexpa and San JuanUnion This work is supported by Convenio bilateral CSIC-CON-ACYT 2001MX0010 J Watkins corrected the English text

REFERENCES

ALBERDI M T J L PRADO AND C CARTELLE 2002 El registro deStegomastodon (Mammalia Gomphotheriidae) en el Pleistoceno su-perior de Brasil Revista Espanola de Paleontologıa 17(2)217ndash235

BARBOUR E H 1927 Preliminary notice of a new proboscidean Ame-belodon fricki gen et sp nov Bulletin Nebraska State Museum 1131ndash134

BARBOUR E H 1929 Torynobelodon loomisi gen et sp nov BulletinNebraska State Museum 1147ndash153

BLUMENBACH J F 1799 Handbuch der Naturgeschichte (sixth edition)Gottingen 708 p

BOESE E 1905 Resena acerca de la Geologıa de Chiapas y TabascoBoletın del Instituto Geologico Mexico 201ndash116

BORISSIAK A A 1928 On a new mastodon from the Chokrak beds(Middle Miocene) of the Kuban region Platybelodon danovi n genn sp Annuaire de la Societe Paleontologique de Russie 7 1927 [1928]105ndash120 (In Russian with English summary)

BURMEISTER H 1837 Handbuch der Naturgeschichte Abtheilung I andII Berlin 795 p

BURNETT G T 1829 Illustrations of the Quadrupeda or quadrupedsbeing the arrangement of the true four-footed beasts indicated in out-line Quarterly Journal of Science London July to December p 336ndash353

CABRERA A 1929 Una revision de los Mastodontes Argentinos Revistadel Museo de la Plata 3261ndash144

CARBOT G F AND M MONTELLANO-BALLESTEROS 2002 Presencia deCuvieronius en Chiapas Mexico VIII Congreso Nacional de Paleon-tologıa Guadalajara Mexico Libro de Resumenes 138

CARRANZA-CASTANEDA O 1976 Rhynchotherium falconeri del RanchoLa Goleta Michoacan Mexico III Congreso Latinoamericano de Geo-logıa Universidad Nacional Autonoma de Mexico Instituto de Geo-logıa Memorias 328

COPE E D 1884 The extinct Mammalia of the Valley of Mexico Amer-ican Philosophical Society Proceedings 221ndash23

COPE E D 1886 Report on the coal deposits near Zacualtipan in theState of Hidalgo Mexico American Naturalist 23146ndash151

CORONA-M E L GARCIA AND E PINA 2000 Registro de un gonfot-erio en Nexpa Morelos VII Congreso Nacional de Paleontologıa y I

Simposio Geologico en el Noreste de Mexico Linares Nuevo LeonLibro de Resumenes 194

CORONA-M E J A QUIROZ-MORENO E JIMENEZ-GARCIA AND M TMONTES-GUERRERO 1999 Rescate de un mastodonte en San JuanUnion Municipio de Taxco de Alarcon Guerrero Arqueologıa 215ndash10

DALQUEST W W AND O MOOSER 1980 Late Hemphillian mammalsof the Ocote local fauna Guanajuato Mexico Texas Memorial Mu-seum Pearce-Sellards series 321ndash25

DEL CASTILLO A 1869 Fossil mammals from the Quaternary formationof the Valley of Mexico Deutsche Geologie Gessellschoff Zeitsch 21479ndash482

DUDLEY J P 1996 Mammoths gomphotheres and the Great AmericanFaunal Interchange p 289ndash295 In J Shoshani and P Tassy (eds) TheProboscidea Evolution and Palaeoecology of Elephants and their Rel-atives Oxford University Press Oxford

EATON G F 1905 Occurrence of Mastodon humboldtii in northern Mex-ico American Journal of Science fourth series 4330

FALCONER H 1868 Paleontological Memoirs and Notes of the late HughFalconer with a Biological Sketch of the Author (ed C Murchinson)Volume 2 Hardwicke London 675 p

FELIX J AND H LENK 1891 Beitrage zur Geologie und Palaontologieder Republik Mexiko Palaeontographica B 37117ndash210

FREUDENBERG W 1922 Die Saugetier Fauna des Pliocans und Postplio-cans von Mexiko II Mastodonten und Elefanten Geologische undPalaontogische Abhandlungen 14103ndash176

FRICK C 1933 New remains of trilophodont-tetrabelodon mastodonsBulletin of the American Museum of Natural History 59505ndash652

HILLSON S 1986 Teeth Cambridge University Press Cambridge 376 pKURTEN B AND E ANDERSON 1980 Pleistocene Mammals of North

America Columbia University Press New York 443 pLAMBERT W D 1996 The biogeography of the gomphotheriid probos-

cideans of North America p 143ndash148 In J Shoshani and P Tassy(eds) The Proboscidea Evolution and Palaeoecology of Elephants andtheir Relatives Oxford University Press Oxford

LUCAS S G AND C M GONZALEZ-LEON 1997 Cuvieronius (Mam-malia Proboscidea) de Oquitoa Sonora Geologıa del Noroeste 2(1)12ndash13

MACFADDEN B J 2000 Middle Pleistocene climate change recorded infossil mammal teeth from Tarija Bolivia and upper limit of the En-senadan Land-mammal age Quaternary Research 54121ndash131

MILLER W E 1980 The Late Pliocene Las Tunas local fauna fromsouthernmost Baja California Mexico Journal of Paleontology 54(4)762ndash805

MILLER W E 1990 A Rhynchotherium skull and mandible from south-eastern Arizona Brigham Young University Geology Studies 3657ndash67

MILLER W E AND O CARRANZA-CASTANEDA 1984 Late Cenozoicmammals from Central Mexico Journal of Vertebrate Paleontology4(2)216ndash236

MILLER W E AND O CARRANZA-CASTANEDA 2002 Importance ofMexicorsquos late Tertiary mammalian faunas p 83ndash102 In M Montel-lano-Ballesteros and J Arroyo-Cabrales (eds) Avances en los estudiospaleo-mastozoologicos en Mexico Col Cientıfica Instituto Nacionalde Antropologıa e Historia Mexico

MONTELLANO-BALLESTEROS M 2002 New Cuvieronius finds from thePleistocene of Central Mexico Journal of Paleontology 76(3)578ndash583

OCHOTERENA H AND A SILVA-BARCENA 1970 Cuvieronius arellanoisp n mastodonte del Pleistoceno del Estado de Oaxaca PaleontologıaMexicana 331ndash25

OSBORN H F 1921 The evolution phylogeny and classification of theProboscidea American Museum Novitates 11ndash15

OSBORN H F 1923 New subfamily generic and specific stages in theevolution of the Proboscidea American Museum Novitates 991ndash4

OSBORN H F 1936 Proboscidea A Monograph of the Discovery Evo-lution Migration and Extinction of the Mastodonts and Elephants ofthe World I Moeritherioidea Deinotherioidea Mastodontoidea TheAmerican Museum Press New York 802 p

PICHARDO DEL BARRIO M 1960 Proboscıdeos fosiles de Mexico Unarevision Boletın del Instituto Nacional de Antropologıa e Historia 41ndash63


POHLIG H 1912 Sur une vieille mandibule de lsquolsquoTetracaulodon ohioti-cumrsquorsquo Blum avec defense in situ Bulletin de la Societe Belge deGeologie 26187ndash193

POLACO O J C ROJAS AND A H GONZALEZ 2002 Una nueva faunapleistocenica de la Penınsula de Yucatan Mexico VIII Congreso Na-cional de Paleontologıa Guadalajara Mexico Libro de Resumenes 173

PRADO J L M T ALBERDI B SANCHEZ AND B AZANZA 2003 Di-versity of the Pleistocene Gomphotheres (Gomphotheriidae Probosci-dea) from South America Deinsea 9347ndash363

SANCHEZ B J L PRADO AND M T ALBERDI 2004 Feeding ecologydispersal and extinction of South American Pleistocene gomphotheres(Gomphotheriidae Proboscidea) Paleobiology 30(1)146ndash161

SHAW C A 1981 The middle Pleistocene El Golfo local fauna fromnorthwest Sonora Mexico Unpublished MSc thesis California StateUniversity Long Beach 141 p

SHOSHANI J 1996 Para- or monophyly of the gomphotheres and theirposition within Proboscidea p 149ndash177 In J Shoshani and P Tassy

(eds) The Proboscidea Evolution and Palaeoecology of Elephants andtheir Relatives Oxford University Press Oxford

TEDFORD R H M F SKINNER R W FIELDS J M RENSBERGER DP WHISTLER T GALUSHA B E TAYLOR J R MACDONALD AND SD WEBB 1987 Faunal succession and biochronology of the Arika-reean through Hemphillian interval (late Oligocene through earliest Pli-ocene epochs) in North America p 153ndash210 In M O Woodburne(ed) Cenozoic Mammals of North America Geochronology and Bio-stratigraphy University of California Press Berkeley

TOBIEN H 1973 On the evolution of mastodonts (Proboscidea Mam-malia) Pt I The Bunodont Trilophodont Groups Notizblatt des Hes-sischen Landesamtes fur bodenforshung zu Wiesbaden 101202ndash276

VON MEYER H 1840 Uber uhdersquos sommling Mexikanishen antiquitatenmineraliend und petrefakten Neues Jahrbuch fur Mineralogie Geolo-gie und Palontologie 1840576ndash587

WEBB S D AND S C PERRIGO 1984 Late Cenozoic vertebrates fromHonduras and El Salvador Journal of Vertebrate Paleontology 4(2)237ndash254

ACCEPTED 25 JANUARY 2005

357

J Paleont 80(2) 2006 pp 357ndash366Copyright q 2006 The Paleontological Society0022-3360060080-357$0300

TWO NEW RECORDS OF GOMPHOTHERIIDAE(MAMMALIA PROBOSCIDEA) IN SOUTHERN MEXICO

AND SOME BIOGEOGRAPHIC IMPLICATIONSEDUARDO CORONA-M1 AND MARIA TERESA ALBERDI2

1Laboratorio de Arqueozoologıa Instituto Nacional de Antropologıa e Historia Moneda 16 Col Centro 06060 Distrito Federal Mexicoecoromacorreounammx and 2Departamento de Paleobiologıa Museo Nacional de Ciencias Naturales CSIC Jose Gutierrez Abascal 2

28006 Madrid Espana malberdimncncsices

ABSTRACTmdashTwo new records of gomphotheriid proboscideans one identified as Rhynchotherium and the other as Cuvieronius arereported in Mexico Both records are in the southwesternmost points of their known distributional range

The remains of both genera consist of molars and tusks Their measurements were compared with data available from the literatureand collection specimens The molar index of Rhynchotherium shows statistical differences between m2 and M2 and m3 and M3However differences between the m3 from both genera are not statistically significant despite slight morphological differences

This suggests that metric and morphological information should be included for a reliable identification of isolated molars and ifavailable any other data of the associated tusk

All known records relating to both genera suggest that they found southwestern Mexico favorable for use as a dispersal corridor toSouth America likely due to the regionrsquos tropical or subtropical climate However some distributional gaps in central Mexico need tobe resolved for Rhynchotherium There are also important populations of Cuvieronius in central Mexico and preliminary informationsuggests that they occupied at least parts of eastern Mexico as well

INTRODUCTION

THE FAMILY Gomphotheriidae is an ancestral group of probos-cideans that are considered to have been chronologically and

biogeographically successful (Tobien 1973 Lambert 1996)North America was an important region for their diversificationand geographical dispersal to South America In North Americaspecimens representing this family are recorded from the middleMiocene to late Pleistocene (Kurten and Anderson 1980 Lam-bert 1996) Their highest level of diversity was from the lateBarstovian to the early Hemphillian during which time six generawere recorded Gomphotherium Burmeister 1837 Rhynchother-ium Falconer 1868 [in Central America see Webb and Perrigo(1984)] Amebelodon Barbour 1927 Platybelodon Borissiak1928 Torynobelodon Barbour 1929 and Serbelodon Frick 1933During the late Hemphillian only three genera have been record-ed Gomphotherium Rhynchotherium and Amebelodon In theBlancan the genera recorded are Rhynchotherium Stegomasto-don Pohlig 1912 and Cuvieronius Osborn 1923 While Rhyn-chotherium became extinct in the Late Blancan Stegomastodonsurvived until the Irvingtonian and Cuvieronius until the Ran-cholabrean (Lambert 1996)

Specimens of gomphotheriids currently assigned to Cuvieron-ius were recorded in Mexico during the nineteenth century byCope (1884 1886) Felix and Lenk (1891) and somewhat laterby Freudenberg (1922) Afterward many of these records wereincorporated in an exhaustive review of the family written byOsborn (1936) However it can be shown that many of thesespecies were named based on the characteristics of isolated mo-lars Recently their status was reviewed by Kurten and Anderson(1980) and Shoshani (1996)

In Mexico remains of gomphotheriids are scarce and oftenlimited to isolated molars and tusks the majority of which werenot recovered from systematic excavations Additionally in a ma-jority of these localities there is no clear stratigraphy RecentlyMiller and Carranza-Castaneda (2002) reviewed the Tertiary lo-calities in Mexico correlating some of them with available dataof their research in central Mexico Nevertheless in the last 20years the record of this family has increased with the report oftwo new findings of the genus Cuvieronius one from Sonora(Lucas and Gonzalez-Leon 1997) and the other from Puebla

(Montellano-Ballesteros 2002) We are also aware of other pre-liminary records that have been identified as Cuvieronius One ofthese is from Chiapas (Carbot and Montellano-Ballesteros 2002)and the other from Yucatan (Polaco et al 2002) We expect fullyreported results of these records in the near future

The objectives of this paper are to detail the two new gom-photheriid localities in Mexico and to describe and provide mea-surements of the material recovered from these localities com-paring with data available from the literature and with specimensfrom Mexican localities In addition the biogeographic implica-tions for both genera are also discussed

LOCALITIES

San Juan Union Taxco GuerreroThe town is approximate-ly 20 km south of the city of Taxco de Alarcon in the state ofGuerrero The excavation site was 1 km north of the town geo-graphically positioned at 188389N 998389W and at 1400 masl(Corona-M et al 1999) (Fig 1)

The locality was located at the confluence of two slopes at thebase of a hill where an artificial pond had been constructed Thefaunal remains were recovered from layers of clay and silt thatwere laden with cobbles and pebbles No other remains associatedwith gomphotheriids either synchronic or diachronic were foundThese combined factors indicate that the remains were a rede-position probably by a shallow debris flow from the highest zoneof the hill to lower zones The gomphotheriid remains had surfacecracks indicative of weathering These marks suggest that the re-mains were frequently covered and uncovered and that this pro-cess probably occurred over a long period of time

Nexpa Tlalquitenango MorelosThis town is located ap-proximately 40 km southeast of the city of Cuernavaca The lo-cality is at the edge of the town on a dirt road constructed downthe slope of a nearby hill that led to the Cuautla River The erosionproduced by the traffic and the rain discovered part of the re-mains and somewhat later was excavated (Corona-M et al2000) The geographic position of this locality was 188319N998089W and 810 masl (Fig 1)

The remains were located in a layer of white clay with cobblesand pebbles The underlying layer is thick and compact and




































Source Locality




Acronym Locality











DISCUSSION












S

Rhynchotherium



S

Cuvieronius














CONCLUSIONS






ACKNOWLEDGMENTS


REFERENCES
























































































Source Locality




Acronym Locality











DISCUSSION












S

Rhynchotherium



S

Cuvieronius














CONCLUSIONS






ACKNOWLEDGMENTS


REFERENCES











































































Source Locality




Acronym Locality











DISCUSSION












S

Rhynchotherium



S

Cuvieronius














CONCLUSIONS






ACKNOWLEDGMENTS


REFERENCES

























































Source Locality




Acronym Locality











DISCUSSION












S

Rhynchotherium



S

Cuvieronius














CONCLUSIONS






ACKNOWLEDGMENTS


REFERENCES























































Source Locality




Acronym Locality











DISCUSSION












S

Rhynchotherium



S

Cuvieronius














CONCLUSIONS






ACKNOWLEDGMENTS


REFERENCES































































S

Rhynchotherium



S

Cuvieronius














CONCLUSIONS






ACKNOWLEDGMENTS


REFERENCES























































S

Rhynchotherium



S

Cuvieronius














CONCLUSIONS






ACKNOWLEDGMENTS


REFERENCES


























































CONCLUSIONS






ACKNOWLEDGMENTS


REFERENCES

























































ACKNOWLEDGMENTS


REFERENCES


































































Documents

TWO NEW RECORDS OF GOMPHOTHERIIDAE (MAMMALIA: PROBOSCIDEA) IN SOUTHERN MÉXICO AND SOME BIOGEOGRAPHIC IMPLICATIONS