Hilarcotherium castanedaii, gen. et sp. nov., a new Miocene astrapothere (Mammalia, Astrapotheriidae) from the Upper Magdalena Valley, Colombia

Abstract

Astrapotheria is an order of extinct South American herbivores recorded throughout the continent, from the late Paleocene to middle Miocene. Here we describe Hilarcotherium castanedaii, gen. et sp. nov., an Uruguaytheriinae astrapothere from sediments of La Victoria Formation (middle Miocene) in the Tolima Department, Upper Magdalena Valley, Colombia. H. castanedaii, represented by a partial skull, mandible, and some postcranial remains, is characterized by (1) unique dental formula, with 0/3i, 1/1c, 1/1p, and 3/3 m; and (2) lower canines with subtriangular transverse section at the base. Hilarcotherium differs from the equatorial Uruguaytheriinae genera Xenastrapotherium and Granastrapotherium in (1) having three lower incisors; (2) the diagonal implantation of the lower canines; (3) lower molars with lingual cingulid; (4) the presence of the hypocone in the third upper molar; and (5) the presence of an anterolingual pocket in the fourth upper premolar. Our phylogenetic analysis supports the monophyly of the subfamilies Astrapotheriinae and Uruguaytheriinae. Within the latter, we confirm the monophyly of the neotropical clade (Hilarcotherium, Xenastrapotherium, and Granastrapotherium). H. castanedaii shows some plesiomorphic features such as the aforementioned presence of the i3 and the developed hypocone in the last upper molar. Its estimated body mass (1303 kg) is intermediate among Astrapotheriidae. http://zoobank.org/urn:lsid:zoobank.org:pub:82377B38-8B39-4D71-9117-FD17CB329238 SUPPLEMENTAL DATA-Supplemental materials are available for this article for free at www.

Extinction of South American sparassodontans (Metatheria): environmental fluctuations or complex ecological processes?

“…() and Vallejo‐Pareja et al . (). Generic richness for all groups was then pooled using the SALMAs as temporal units.…”

A 60-million-year Cenozoic history of western Amazonian ecosystems in Contamana, eastern Peru

“…Mollusk, arthropod, and vertebrate faunas from La Guajira Peninsula and the Socorro-Urumaco formations in Venezuela (Fig. 1A) further indicate the presence of biotic connections between the paleo-Amazonas-Orinoco system and coastal areas of Colombia-Venezuela during Neogene times (Sánchez-Villagra et al, 2000Sánchez-Villagra and Scheyer, 2010;Rincón et al, 2014;Hendy et al, 2015;Jaramillo et al, 2015;Moreno et al, 2015;Salas-Gismondi et al, 2015;Vallejo-Pareja et al, 2015).…”

The Neogene Record of Northern South American Native Ungulates

“…Astrapotheria is a clade of SANUs recorded from the early Eocene (Itaboraian SALMA; Soria and Powell, 1981;Soria, 1987;Kramarz and Bond, 2013;Woodburne et al, 2014a,b;Kramarz et al, 2017) to the middle Miocene (12.76-13.6 mya, Laventan SALMA; Johnson, 1984;Johnson and Madden, 1997;Goillot et al, 2011;Vallejo-Pareja et al, 2015). The clade had a large body mass range between ~60 kg (Albertogaudrya; Vizcaíno et al, 2012) and ~4117 kg (Parastrapotherium herculeum?…”

“…The latter comprises two clades: Astrapotheriinae, consisting of the southern taxa Astrapotherium and Astrapothericulus, and Uruguaytheriinae, which is composed of Uruguaytherium, Granastrapotherium, Xenastrapotherium and Hilarcotherium. The Uruguaytheriinae is supported by dental characters such as the absence of hypoflexid, absence of pillar in the lower molars, and absence of a labial cingulum (Johnson and Madden, 1997;Bond, 2009, 2011;Vallejo-Pareja et al, 2015).…”

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