Papers by Laura Chornogubsky
Journal of Mammalian Evolution, Feb 11, 2023
Ameghiniana
This work describes two new materials corresponding to Pachybiotherium illuminatum, a microbiothe... more This work describes two new materials corresponding to Pachybiotherium illuminatum, a microbiotheriid from Pinturas Formation (early Miocene, Santa Cruz Province, Argentina) previously reported at the lower levels of the Formation on Portezuelo Sumich Sur, now recorded in lower levels of Portezuelo Sumich Norte and the possibly upper levels of Los Toldos Sur localities. The new specimens offer a better understanding of P. illuminatum upper molars morphology and, if the level assignation was correct, allow us to argue that 1) P. illuminatum is reported for the first time as appearing on a typical Santacrucian fauna; 2) the “Pinturan” and Santacrucian faunas at the Rio Pinturas localities are more similar than previously reported; 3) the biochron of the species is extended.
Journal of South American Earth Sciences, 2021
Abstract In the Eocene deposits of Northwestern Argentina, the order Cingulata was recognized in ... more Abstract In the Eocene deposits of Northwestern Argentina, the order Cingulata was recognized in the sedimentary levels of the upper and lower sections of the Lumbrera (Salta Province), Geste (Catamarca and Salta provinces), Quebrada de Los Colorados (Salta Province), and Casa Grande (Jujuy Province) formations. The traditional biochronological scheme associated the Geste Formation to the Mustersan SALMA (37.3–35.4 Ma; Priabonian), the lower section of the Lumbrera Formation to the Vacan Subage (44–46 Ma; Lutetian) of the Casamayoran SALMA, and the fossiliferous levels of the remaining units to the Barrancan Subage (39–42 Ma; Bartonian) of the Casamayoran SALMA. Nevertheless, recent dating obtained for the top of the lower section of the Lumbrera Formation supports a new geochronological framework for Northwestern Argentina, which changes the temporal assignation of the taxa that have been collected in this section, going from the Vacan Subage to the Itaboraian SALMA, affecting also the biochronology of the Quebrada de Los Colorados and the upper section of the Lumbrera formations, which are now constrained between 46 and 40 Ma (Lutetian). In this contribution, we present a new cingulate assemblage based on osteoderms collected in the basal levels of the Quebrada de Los Colorados Formation at Los Cardones National Park, Calchaqui Valley (Salta, Northwestern Argentina), which is constituted by a new taxon plus Pucatherium parvum and Parutaetus punaensis. In addition, we discuss all the Eocene cingulate associations reported for Northwestern Argentina taking into consideration the new geochronological framework.
Revista del Museo Argentino de Ciencias Naturales, 2021
Desde hace varias décadas, las desigualdades de género en la ciencia y el rol que ha ocupado la m... more Desde hace varias décadas, las desigualdades de género en la ciencia y el rol que ha ocupado la mujer en diversas disciplinas científicas han comenzado a ser analizadas y cuestionadas (e.g.,
<i>Astegotherium</i>, sp. nov. Figure 5E Several isolated plates from Laguna Fría are... more <i>Astegotherium</i>, sp. nov. Figure 5E Several isolated plates from Laguna Fría are assigned to this new taxon. This small dasypodid is of similar size to the living <i>Dasypus hybridus</i> or <i>D. septencinctus</i>, with very thin and smooth osteoderms, and a lageniform central figure in the movable scutes, as in <i>A. dichotomus</i>, from the Casamayoran (Vacan, Carlini et al. 2002c); very few (or no) foramina surrounding the central figure; poorly defined sulcus separating the central figure from the peripheral ones. The central keel of the exposed surface is even less elevated than in the Casamayoran species, and has one or rarely two large foramina on the posterior margin. Genus <i>Stegosimpsonia</i> Vizcaíno, 1994
Fig. 10. Top: General view of the measured area shown in figure 9. LF: fossiliferous levels; I: u... more Fig. 10. Top: General view of the measured area shown in figure 9. LF: fossiliferous levels; I: underlying ignimbrite dated in 49.51 ± 6 0.32 Ma; AH: Andesitas Huancache, overlying basalts dated in 47.89 ± 6 1.21 Ma. Bottom: Partial exposures of the Laguna Fría (LF) section and the Barda Colorada ignimbrite (IBC); between both levels is the ignimbrite mentioned above (I), underlying Laguna Fría.
Fig. 7. South American native ungulates from Laguna Fría (LF) and La Barda (LB). A, LIEB-PV 1612,... more Fig. 7. South American native ungulates from Laguna Fría (LF) and La Barda (LB). A, LIEB-PV 1612, Didolodontidae, gen. et sp. nov., right m2–3; B, Asmithwoodwardia subtrigona, LIEB-PV 1636, left M2; C, Asmithwoodwardia subtrigona, LIEB-PV 1617, right m2; D, Spartnotheriodontidae, Gen. et sp. indet. G, MLP-66-V-12-2, right maxillary fragment with three molariforms (P4–M2?) (LF); E, Henricosbornia lophofonta, LIEB-PV 1633, right maxilla with P4–M2 (LB); F, Othnielmarshia lacunifera, LIEB-PV 1618, right maxilla with M1–3 (LF); G, Edvardotrouessartia sola, LIEB-PV 1619; right maxilla with P2–4 (LF); H, Isotemnus sp., LIEB-PV 1646, right maxilla with P4–M3 (LF); I, Isotemnus sp., LIEB-PV 1659, left m2 (LF). Scale bar 5 1 mm.
Fig. 8. Results of the cluster analysis using data matrix of 118 genera and eight faunas/SALMAs d... more Fig. 8. Results of the cluster analysis using data matrix of 118 genera and eight faunas/SALMAs described in table 1.
Fig. 9. Measured section in the type area of the Laguna Fría Fauna, about 500 meters northeast of... more Fig. 9. Measured section in the type area of the Laguna Fría Fauna, about 500 meters northeast of the type locality.
Fig. 3. Marsupials from Laguna Fría (LF) and La Barda (LB). A, Peradectidae gen. et sp. nov., LIE... more Fig. 3. Marsupials from Laguna Fría (LF) and La Barda (LB). A, Peradectidae gen. et sp. nov., LIEB- PV 1031 (LF); B, Caroloameghiniidae gen. et sp. nov., LIEB-PV 1098 (LF); C, Peradectoidea gen. et sp. nov., LIEB-PV 1097, left M3 (LB); D, Protodidelphis sp. nov., LIEB-PV 1091, left M?3 (LB); E, Pauladelphys sp. nov., LIEB-PV 1123, m2 in a fragment of right dentary (LF); F, cf. Itaboraidelphys sp., LIEB-PV 1064, an isolated right m2 or m3 (LF); G, Paucituberculata gen. et sp. nov. 1, LIEB-PV 1135, a left maxillary fragment with M2–3 and part of M4 (LF); H, Sparassodonta, Hathliacynidae, gen. et sp. nov. LIEB-PV 1036, M?3 in a maxillary fragment (LF); I, Eomicrobiotherium sp., LIEB-PV 1040, a right m?3 (LF); J, Palangania sp., LIEB-PV 1106, left M?3 (LB); K, Gashternia ctalehor, LIEB-PV 1132, a right M4 (LB).
Fig. 5. Dasypodidae from Laguna Fría (LF) and La Barda (LB) assemblages. A, scutes of Riostegothe... more Fig. 5. Dasypodidae from Laguna Fría (LF) and La Barda (LB) assemblages. A, scutes of Riostegotherium sp. nov. from LF; B, scutes of Riostegotherium sp. nov. from LB; C, scutes of Prostegotherium cf. astrifer from LF; D, scutes of Prostegotherium cf. astrifer from LB; E, scutes of Astegotherium sp. nov. from LF; F, scutes of Stegosimpsonia sp. nov. from LF (also in LB, but not shown). Scale bar 5 10 mm.
Fig. 2. Stratigraphic column including the localities of Laguna Fría and La Barda.
List of synapomorphies for "New tarsal remains suggest the existence of non microbiotherian ... more List of synapomorphies for "New tarsal remains suggest the existence of non microbiotherian Australidelphian marsupials (Diprotodontia) in the Eocene of Patagonia
Data matrix modified from Beck (2012)
A diverse assemblage of extinct mammals of early–middle Eocene age (Ypresian–Lutetian boundary) c... more A diverse assemblage of extinct mammals of early–middle Eocene age (Ypresian–Lutetian boundary) come from the Patagonian localities of La Barda and Laguna Fría around Paso del Sapo in northwestern Chubut Province (Argentina). Metatherians are well represented, mostly by dental remains of ‘Didelphimorphia’, Paucituberculata, Sparassodonta, Microbiotheria, and Polydolopimorphia. Here we analyse three calcanea and one astragalus referable to the same, indeterminate taxon, from La Barda, showing the fusion of their ectal and sustentacular facets. This facet arrangement characterizes the Australidelphia, a marsupial clade represented by Microbiotheria from South America and Antarctica, plus all Australasian lineages. Other australidelphian features shown by these tarsals include: in the calcanea, a reduced peroneal process and a tripartite cuboid facet; in the astragalus, a round, very small astragalar head in relation to the body; a convex trochlea with a half for the tibia and half, in slightly lower position, for the fibula. Their size and other anatomical features suggest that the new tarsals cannot be referred to the Microbiotheria. Phylogenetic analysis suggests that the La Barda taxon lies within the Australidelphia, and that it is either closely related or belongs to, the Diprotodontia. The existence of advanced australidelphians in Patagonia adds further evidence of the close relationship between Patagonia, Antarctica, and Australia during the Late Cretaceous – early Palaeogene
Acta Palaeontologica Polonica, 2021
In the last few years, the Quebrada de Los Colorados Formation has become an important middle Eoc... more In the last few years, the Quebrada de Los Colorados Formation has become an important middle Eocene fossiliferous unit in Northwestern Argentina. In this unit, the South American native ungulates were until now only represented by the order Notoungulata, including one family of Typotheria and three of Toxodontia. In this contribution, we present a new faunistic assemblage of South American native ungulates, collected from outcrops of the Quebrada de Los Colorados Formation at Los Cardones National Park, Calchaquí Valleys, Salta Province (Argentina). This new assemblage is constituted by the following taxa: litoptern Didolodontidae cf. Ernestokokenia sp., Astrapotheria indet., and notoungulate Notostylopidae Homalostylops sp., a ?Homalostylops sp., typothere "Oldfieldthomasiidae" Colbertia falui sp. nov., Colbertia lumbrerense, and Colbertia sp. and toxodont "Notohippidae" Pampahippus secun dus. Colbertia falui sp. nov. differs from the other species of Colbertia by the following features: lower cheek teeth with both more labially angular and oblique trigonid; lower premolars more labio-lingually compressed; with proportionally larger trigonid, and shorter talonid; ectoflexid transversally deeper; lower molars with a more developed paralophid, and more expanded metalophid and entoconid; the latter is located in a more mesial position, being closer to the metaconid; deep and lingually narrower talonid basin; disto-lingual sulcus transversally shallower; more developed cingulids; and m3 with less lingually projected hypoconulid. This new fauna markedly increases the taxonomic richness known for this formation since it includes the first mention of notostylopids, "oldfieldthomasiids", litoptern didolodontids, and astrapotheres. With the current evidence, we postulate an ungulate migration from Patagonia to Northwestern Argentina during the Eocene. We also hypothesize that the observed taxonomic differences among the Quebrada de Los Colorados, Geste, and Lumbrera formations are more probably associated to orogenic factors that have regulated the faunal dynamic in Northwestern Argentina during the Paleogene than to a differential sampling effort or taphonomic biases. K ey w o r d s : Mammalia, South American native ungulates, Casamayoran SALMA, Paleogene, Quebrada de Los Colorados Formation, Argentina.
Journal of Mammalian Evolution, 2021
Recently, the basal beds of the lower section of the Lumbrera Formation have been referred to the... more Recently, the basal beds of the lower section of the Lumbrera Formation have been referred to the early Eocene (Ypresian) based on the identification of a succession of hyperthermal events globally dated between 52 and 55 Ma. Nevertheless, this section have also been referred to the middle Eocene (Lutetian) based on the ‘evolutionary stage’ of its fossil mammals. In this contribution, we present a new 238U-206Pb isochron age (46.2 Ma) obtained from samples taken on various independent points across paleosol and matrix positioned at the top of the lower section of the Lumbrera Formation. The new age is consistent with the hyperthermal scheme and constrains the deposition of the lower section of the Lumbrera Fm. between 55–46.2 Ma. In this new geochronological framework, we present one of the most ancient cingulate assemblages from America, recorded during the early Eocene hyperthermal. The specimens involved were recovered from the lowest levels of the lower section of the Lumbrera Formation at Los Cardones National Park, Calchaqui Valleys, Salta Province, Argentina. This cingulate assemblage is formed by the armadillos Pucatherium parvum, a species widely distributed in the Eocene of northwestern Argentina and a new taxon, Noatherium emilioi, gen. et sp. nov. In this new geochronological framework, the taxonomic composition and morphological variations observed in the two species described here and their probably contemporaneous Riostegotherium yanei from the Itaborai basin (Brazil) support an early diversification of the Cingulata during the Paleocene, and reinforce an intertropical origin for the group.
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Papers by Laura Chornogubsky