The record of camelids (Artiodactyla, Camelidae) from the Valsequillo Basin, late Pleistocene of Puebla State, Central Mexico: taxonomy, diet, and geographic distribution

Abstract

-Dental and postcranial fossil material referable to camelids, which has been recovered from Quaternary deposits that outcrop in the Valsequillo Basin, Puebla State, central Mexico, is formally described. A comparative study indicates the presence of two species of camelids, including Hemiauchenia macrocephala and Camelops hesternus. The sample referable to H. macrocephala includes maxillary and mandibular fragments, isolated teeth, and several postcranial remains (astragalus, metapodials, and proximal phalanges), which show the following diagnostic features of the species: molariforms covered by a layer of cementum; a mandible increasing in depth from p4 to m3; p4 triangular in outline; long and slender metapodials; and proximal phalanges with a W-shaped suspensory ligament scar. The sample referable to C. hesternus is represented by maxillary and mandibular fragments, isolated teeth, and metapodials, sharing with the species its large size; P4 quadrate in outline; p4 triangular in outline and simply folded; and a mandible that is significantly deeper from p4 to m3. A microwear analysis was performed in order to characterize the diet of studied samples, indicating a browser and mixed feeding behavior in H. macrocephala and C. hesternus respectively. The differences in size and trophic regimes in these species should explained the resource partitioning between them. In the late Pleistocene these camelids were common in Mexican sites between the 19°-25° N, and the record from the Valsequillo Basin is one of the few sites where both species have been reported. Key words: Camelidae, taxonomy, diet, geographic distribution, Valsequillo Basin, Quaternary.RESUMO -Material fóssil dentário e pós-craniano atribuído a camelídeos, recuperados de depósitos quaternários aflorantes na Bacia Valsequillo, Estado de Puebla, México central, é descrito formalmente. Um estudo comparativo indica a presença de duas espécies de camelídeos, Hemiauchenia macrocephala e Camelops hesternus. A amostra atribuída a H. macrocephala inclui fragmentos maxilares e mandibulares, dentes isolados, e vários restos pós-cranianos (astrágalos, metapodiais e falanges proximais), que mostram os seguintes caracteres diagnósticos da espécie: molariformes coberto por uma camada de cemento; uma mandíbula aumentando em altura do p4 ao m3; p4 de aspecto triangular; metapodiais longos e finos; e falanges proximais com uma cicatriz no ligamento suspensório em forma de W. A amostra atribuída a C. hesternus é representada por fragmentos maxilares e mandibulares, dentes isolados, e metapodiais, compartilhando com a espécie seu grande tamanho; P4 com aspecto quadrangular; p4 de contorno triangular e simplesmente dobrado; e uma mandíbula que é significantemente mais alta de p4 a m3. Uma análise de micro-desgaste foi realizada a fim de caracterizar a dieta de amostras estudadas, indicando hábito ramoneador e a alimentação mista em H. macrocephala e C. hesternus respectivamente. As diferenças de tamanho e regimes tróficos nestas espécies deve explicar a partil...

Paleoenvironmental changes in the Brazilian Pampa based on carbon and oxygen stable isotope analysis of Pleistocene camelid tooth enamel

“…The results presented here, albeit limited, agree with the interpretation of camelid feeding strategies based on muzzle anatomy (Dompierre and Churcher 1996), hypsodonty indexes (HI) (Feranec 2003) and microwear features (Semprebon and Rivals 2010, Bravo‐Cuevas et al 2016). Although camelids were browsers, the increased consumption of grasses observed in the South American taxa reflects their phylogenetic history (Pérez‐Barbería et al 2001, Feranec 2003), the ancestral Hemiauchenia being characterized as an intermediate feeder with a preference for browsing, and the more derived Lama and Vicugna as intermediate feeders, with preferences for grazing and pure grazing, respectively.…”

“…Most of these specimens were C3 browsers or mixed C3–C4 feeders, although the highest proportion of C4 plants recorded in Rancholabrean specimens indicates 100% grazing diets, probably reflecting changes in plant communities through the Quaternary (MacFadden and Cerling 1996, Feranec 2003, Yann et al 2016). Browsing diets of Hemiauchenia from Mexico were also indicated by δ 13 C = −10.0‰ in a specimen from the Sonoran Desert (Nunez et al 2010), and by microwear features in fossils from Puebla (Bravo‐Cuevas et al 2016). On the other hand, the H. paradoxa from the Argentinean Pampa (see below) were mixed feeders (Domingo et al 2020), whereas the δ 13 C values in collagen and apatite of four specimens from the late Pleistocene–early Holocene Pilauco archeological site in Chile indicate browsing in forested habitats (González‐Guarda et al 2017).…”

“…coexistence in the same area), through exploitation of different food resources (niche partitioning), with L. guanicoe occupying the mixed feeder niche and H. paradoxa a C3 browser niche. That difference could also indicate occupation of variable spatial ranges within the same landscape as proposed to explain the co‐occurrence of H. macrocephala (browser) and Camelops hesternus (mixed feeder) from Mexico (Bravo‐Cuevas et al 2016), or reflect seasonal migrations between areas with distinct plant assemblages (Rivals et al 2013).…”

“…, and by microwear features in fossils from Puebla(Bravo-Cuevas et al 2016). On the other hand, the H. paradoxa from the Argentinean Pampa (see below) were mixed feeders(Domingo et al 2020), whereas the δ 13 C values in collagen and apatite of four specimens from the late Pleistocene-early Holocene Pilauco archeological site in Chile indicate browsing in forested habitats(González-Guarda et al 2017).…”

Descripción de las huellas de camélidos y félidos de la localidad Pie de Vaca, Cenozoico Tardío de Puebla, centro de México y algunas consideraciones paleobiológicas

“…Las llamas del género Hemiauchenia del Plioceno y Pleistoceno de Norteamérica son algo más grandes que una llama actual (Lange, 2002). Por lo anterior, es probable que los camélidos que generaron los rastros hayan sido representantes de ese género de lamines, el cual fue bastante común a lo largo del territorio nacional durante el Cenozoico tardío (Jiménez-Hidalgo y Carranza-Castañeda, 2010; Bravo-Cuevas et al, 2012, 2016a. La dirección de los rastros, los valores de velocidad y modalidad de progresión de los organismos que los produjeron, así como la profundidad de las huellas, son evidencia utilizada para establecer un comportamiento gregario a través de huellas (Castanera et al, 2012).…”