Tracing evolutionary parallelisms between Glyptodontinae and Dasypodinae (Xenarthra, Cingulata)

DANIEL BARASOAIN; FRANCISCO CUADRELLI; ALFREDO ARMANDO CARLINI; JUAN SEBASTIÁN SALGADO AHUMADA

Congreso; Reunión de Comunicaciones de la Asociación Paleontológica Argentina 2022; 2023

Glyptodontinae constitutes the clade with the greatest latitudinal distribution of glyptodonts, including the genera Boreostemma (middle Miocene), Glyptotherium (Late Pliocene-Late Pleistocene), and Glyptodon (Middle Pleistocene-Late Pleistocene). In turn, Dasypodinae is a clade of “armadillos” including the genera Plesiodasypus (middle Miocene), Anadasypus (middle-Late Miocene), Pliodasypus(Pliocene), Propraopus (Pleistocene-Early Holocene) and Dasypus (Late Pliocene-current). Both lineages have different morphologies and ecological niches. While the Glyptodontinae are large-sized, (ca. 450-800 kg in the terminal species), and usually interpreted as generalist grazers, the Dasypodinae are medium-sized armadillos (ca. 8-15 kg in Dasypus species) interpreted as generalist to mainly insectivore forms. Despite these ecological and morphological differences, the evolutionary/paleobiogeographic history of Glyptodontinae and Dasypodinae shows marked similarities: 1) a low latitudinal origin in South America (earliest records from La Venta, Colombia); 2) they respectively represent the sister-group of the remaining diversity of glyptodonts and “armadillos”, implying an early divergence; 3) they have a relatively high abundance and wide distribution (ca. 35°N-38°S) but a low diversity compared to other lineages; 4) they represent the only groups of their families to have crossed and diversified in North America during the GABI (e.g., Glyptotherium and Dasypus). From a palaeoecological viewpoint, the environments in northern-most South America during the Miocene were warm and humid. These conditions are commonly related to lineages with great distribution capacities, giving place to highly plastic derived species, while conserving representatives in their ancestral area (e.g., Glyptotherium cf. G. cylindricum from the late Pleistocene or Dasypus spp. from Holocene, both from northern-most South America). The arrival of Glyptodontinae (“Glyptodontidium”) and Dasypodinae to high latitudes in South America is coincident with the maximum expression of the “Age of the Southern Plains” (Late Miocene-Pliocene). Regarding North America, both reached similar latitudes although under different climatic conditions. The northernmost record of Glyptodontinae (Glyptotherium) coincides with a warm period during the Late Pliocene. Later on, during the Pleistocene, the climate became progressively drier, causing their distributional retraction. Contrary, the first presence of Dasypodinae (Dasypus) for these latitudes is concordant with the drought events that caused the retraction of glyptodonts. In summary, the lower diversification, together with a high dispersal potential, has been previously reported for other groups of mammals with intertropical origin (e.g., Rodentia). In this scenario, a common temporal and geographic origin between Dasypodinae and Glytodontinae could explain the parallelism in their paleobiogeographic history. This pattern has not been previously reported for other Cingulata lineages.