The aquatic sloth<i>Thalassocnus</i>(Mammalia, Xenarthra) from the late Miocene of North-Central Chile: biogeographic and ecological implications

Canto, Jhoann; Salas-Gismondi, Rodolfo; Cozzuol, Mário Alberto; Yanez, J Pena

doi:10.1671/0272-4634(2008)28[918:tastmx]2.0.co;2

Cited by 20 publications

(30 citation statements)

References 16 publications

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“…The material (SGO.PV1093) was referred to T. antiquus or T. natans (Canto et al, 2008), consistent with the assignment of the deposits to the late Miocene, as indicated by radiometric ages derived from ash levels in the formation.…”

Section: Also Appearing In This Issuesupporting

confidence: 80%

“…As only T. antiquus or T. natans were previously reported in Chile (Canto et al, 2008;Pyenson et al, 2014), the Lomas del Sauce specimen represents the first occurrence of the younger species T. carolomartini outside the Peruvian Pisco (Muizon et al, 2004b;Amson et al, 2015d). Currently, seagrasses are largely restricted to tropical and subtropical areas, so it is important to note that today they are only known along the modern Pacific coast of South America by a small meadow in the Coquimbo district (Kuo, 2005) of coastal Chile, a patch most likely insufficient to sustain a population of large marine grazers.…”

Section: Discussionmentioning

confidence: 95%

“…Chile, in the Bahía Inglesa Formation, had already been reported (Canto et al, 2002(Canto et al, , 2008Walsh and Suárez, 2005;Suárez et al, 2011;Pyenson et al, 2014). The first report of…”

Section: Also Appearing In This Issuementioning

confidence: 87%

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The Southernmost Occurrence of the Aquatic SlothThalassocnus(Mammalia, Tardigrada) in Two New Pliocene Localities in Chile

Arcos¹,

Partarrieu

Carrillo-Briceño

et al. 2017

Ameghiniana

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Thalassocnus is a sloth (Mammalia, Tardigrada) adapted to an aquatic lifestyle. It was first described from the Neogene deposits of the Pisco Formation of Peru, from where most of the specimens come. The genus is represented by five species ranging from the late Miocene to the late Pliocene, occupying successive stratigraphic levels. Morpho-functional studies of the cranial and postcranial skeleton of Thalassocnus have demonstrated the progressive adaptation of these sloths to a marine environment, establishing gradual differences from from the geologically oldest to the youngest species of the genus. The first records of Thalassocnus outside the Pisco Formation have been referred to the Neogene Bahía Inglesa Formation, in northern Chile, where older species were recovered. In this paper, we describe materials from two new Pliocene localities in Chile: the Coquimbo and the Horcón formations, in northern and central Chile, respectively. The Coquimbo Formation material was collected from the Lomas del Sauce locality and consists of a partial skeleton of a single individual. Detailed comparisons of the elements with diagnostic features enabled the referral of this specimen to T. carolomartini. The material from the Horcón Formation was collected from the Playa La Luna locality and consists of an isolated phalanx, which is attributed to one of the species of Thalassocnus younger than T. natans. Thus, we present the first record of younger species of Thalassocnus in Chile and the southernmost occurrence of the genus. Key words. Coquimbo Formation. Horcón Formation. Marine assemblage. Tardigrada. Thalassocnus. Xenarthra. Resumen. EL HALLAZGO MÁS MERIDIONAL DEL PEREZOSO MARINO THALASSOCNUS (MAMMALIA, TARDIGRADA) EN DOS NUEVAS LOCALIDADES DEL PLIO-CENO DE CHILE. Thalassocnus es un perezoso (Mammalia, Tardigrada) adaptado al medio acuático que fue descrito por primera vez en depósitos neógenos de la Formación Pisco en Perú, de la cual procede la mayor parte de los especímenes conocidos. El género está representado por cinco especies, que se extienden desde el Mioceno tardío al Plioceno tardío, ocupando niveles estratigráficos sucesivos. Estudios morfo-funcionales del esqueleto craneal y postcraneal de Thalassocnus han permitido constatar la progresiva adaptación de este perezoso al medio acuático, desde las especies geológicamente más antiguas a las más recientes. Los primeros registros de Thalassocnus fuera de la Formación Pisco corresponden a la Formación Bahía Inglesa, del Neógeno del Norte de Chile, y fueron asignados a las especies antiguas. En este trabajo describimos material de Thalassocnus procedente de dos nuevas localidades en depósi-tos pliocenos de las formaciones Coquimbo y Horcón, del Norte y Centro de Chile respectivamente. El material de la Formación Coquimbo proviene de la localidad Lomas del Sauce y pertenece a un único individuo que conserva buena parte del esqueleto postcraneal. La comparación detallada de aquellos elementos óseos con características diagnósticas ha permitido asignarlo a T....

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Section: Also Appearing In This Issuesupporting

confidence: 80%

Section: Discussionmentioning

confidence: 95%

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The Southernmost Occurrence of the Aquatic SlothThalassocnus(Mammalia, Tardigrada) in Two New Pliocene Localities in Chile

Arcos¹,

Partarrieu

Carrillo-Briceño

et al. 2017

Ameghiniana

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“…The excellent preservation of vertebrate fossils from the Pisco Formation yielded five Thalassocnus species, the first well-preserved and nearly continuously represented xenarthran lineage for which it is possible to trace the evolution of feeding and aquatic adaptations (Muizon et al 2004). Thalassocnus remains have recently been described from the late Miocene of northern Chile (Bahía Inglesa Formation), expanding its range outside the Pisco Formation (Canto et al 2008). …”

Section: Discovery Of "Peculiar" Sloths and New Prospecting Areasmentioning

confidence: 99%

Recent Advances on Variability, Morpho-Functional Adaptations, Dental Terminology, and Evolution of Sloths

et al. 2012

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The occasion of the Xenarthra Symposium during the ICVM 9 meeting allowed us to reflect on the considerable advances in the knowledge of sloths made by the "Xcommunity" over the past two decades, particularly in such aspects as locomotion, mastication, diet, dental terminology, intraspecific variation, sexual dimorphism, and phylogenetic relationships. These advancements have largely been made possible by the application of cladistic methodology (including DNA analyses) and the discovery of peculiar forms such as Diabolotherium, Thalassocnus, and Pseudoglyptodon in traditionally neglected areas such as the Chilean Andes and the Peruvian Pacific desert coast. Modern tree sloths exhibit an upside-down posture and suspensory locomotion, but the habits of fossil sloths are considerably more diverse and include locomotory modes such as inferred bipedality, quadrupedality, arboreality or semiarboreality, climbing, and an aquatic or semi-aquatic lifestyle in saltwater. Modern tree sloths are generalist browsers, but fossil sloths had browsing, grazing, or mixed feeding dietary habits. Discovery of two important sloth faunas in Brazil (Jacobina) and southern North America (Daytona Beach and Rancho La Brea) have permitted evaluation of the ontogenetic variation in Eremotherium laurillardi and the existence of possible sexual dimorphism in this sloth and in Paramylodon harlani. A new dental terminology applicable to a majority of clades has been developed, facilitating comparisons among taxa. An analysis wherein functional traits were plotted onto a phylogeny of sloths was used to determine patterns of evolutionary change across the clade. These analyses suggest that megatherioid sloths were primitively semiarboreal or possessed climbing adaptations, a feature retained in some members of the family Megalonychidae. Pedolateral stance in the hindfoot is shown to be convergently acquired in Mylodontidae and Megatheria (Nothrotheriidae + Megatheriidae), this feature serving as a synapomorphy of the latter clade. Digging adaptations can only be securely ascribed to scelidotheriine and mylodontine sloths, and the latter are also the only group of grazing sloths, the remainder being general browsers.

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“…Since that discovery, four additional species of the Thalassocnus lineage have been described from the late Miocene-late Pliocene (McDonald and Muizon, 2002;Muizon et al 2003Muizon et al , 2004a. (Canto et al 2008) indicates that the aquatic sloth lineage was not endemic to Peru as previously suggested. (Canto et al 2008) indicates that the aquatic sloth lineage was not endemic to Peru as previously suggested.…”

Section: Origin and Evolutionmentioning

confidence: 69%

Sirenians and Other Marine Mammals

Berta

Sumich²,

Kovacs³

2015

Marine Mammals

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The aquatic slothThalassocnus(Mammalia, Xenarthra) from the late Miocene of North-Central Chile: biogeographic and ecological implications

Cited by 20 publications

References 16 publications

The Southernmost Occurrence of the Aquatic SlothThalassocnus(Mammalia, Tardigrada) in Two New Pliocene Localities in Chile

The Southernmost Occurrence of the Aquatic SlothThalassocnus(Mammalia, Tardigrada) in Two New Pliocene Localities in Chile

Recent Advances on Variability, Morpho-Functional Adaptations, Dental Terminology, and Evolution of Sloths

Sirenians and Other Marine Mammals

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