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Monday, August 11th, 2025
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| 12:16a | [PaleoMammalogy • 2025] Yeutherium pressor • A subantarctic reigitheriid and the evolution of crushing teeth in these enigmatic Mesozoic mammals
Abstract Mesozoic mammals from Gondwana remain poorly understood, with most species known only from isolated teeth. Nevertheless, these tantalizing fossils point to a diversity of families that were distinct from Laurasian forms. Among these, the enigmatic South American family Reigitheriidae was proposed based on the unique crushing teeth of its sole representative, Reigitherium, from Northern Patagonia. Here, we report a new mammal, Yeutherium pressor gen. et sp. nov., which is only the second known taxon of Reigitheriidae. This is based on a partial maxilla bearing an upper molar from the Late Cretaceous Dorotea Formation in the Río de Las Chinas valley, Sub-Antarctic Chile. Parsimony and Bayesian phylogenetic analyses indicate a close relationship between Reigitherium and Yeutherium. Shared features between both taxa—such as expanded preparacristae and postparacristae, a lingual cingulum at the paracone base, interradicular crests and enamel crenulations—help define Reigitheriidae. Cingula development and molar morphology of Yeutherium differ from that of the related Mesungulatidae, suggesting independent evolution of the crushing adaptations in Reigitheriidae. Additionally, we suggest a reinterpretation of the dental formula of Reigitheriidae. The discovery of Yeutherium highlights the specialized dentition of Reigitheriidae as a significant functional innovation in a radiation of Gondwanan mammals that is starting to be understood. Keywords: Mammalia, Meridiolestida, Mesungulatoidea, Reigitheriidae, Patagonia, Cretaceous   Yeutherium pressor gen. et sp. nov.  Hans P. Püschel, Agustin G. Martinelli, Sergio Soto-Acuña, Héctor Ortiz, Marcelo Leppe and Alexander O. Vargas. 2025. A subantarctic reigitheriid and the evolution of crushing teeth in these enigmatic Mesozoic mammals. Proc. R. Soc. B. 292: 20251056. DOI: doi.org/10.1098/rspb.2025.1056 [06 August 2025] https://x.com/PuschelHans/status/1952915  | ||||||||||
| 12:49p | [Botany • 2025] Ceratostema revoluta (Ericaceae) • A New Species with nearly tubular leaves from the Cordillera del Cóndor, Ecuador
Abstract A new species of Ceratostema from the Cordillera del Cóndor in Ecuador is described and illustrated. Ceratostema revoluta is distinguished by its nearly tubular leaves with revolute margins, pulvinate petioles, reddish flowers with white base and brownish to black lobes, short, complanate pedicel with carinate bracteoles appressed to the base and calyx lobes appressed to the corolla and overlapping each other below the middle. The taxonomic similarities of the new species are discussed and information about its distribution, habitat and conservation is provided. Key words: Northern Andes, Morona Santiago, south-eastern Ecuador, taxonomy
Ceratostema revoluta M.M.Jiménez, H.Garzón & Iturralde, sp. nov. Diagnosis. Ceratostema revoluta is distinguished from other members of the genus by its nearly tubular, linear-lanceolate leaves with revolute margins, pulvinate petioles, sessile inflorescences with reddish flowers with white base and brownish to black lobes, short complanate pedicels with basal carinate appressed bracteoles and appressed calyx lobes that overlap each other below the middle (Fig. 1). Etymology. The new species is named by the strongly revolute margins of the leaves. Marco M. Jiménez, Henry X. Garzón-Suárez and Gabriel A. Iturralde. 2025. A New Species of Ceratostema (Ericaceae) with nearly tubular leaves from the Cordillera del Cóndor, Ecuador. PhytoKeys. 261: 77-86. DOI: doi.org/10.3897/phytokeys.261.156555 | ||||||||||
| 2:41p | [Herpetology • 2025] Gonyosoma iadinum • A New Species of the Gonyosoma prasinum species complex (Serpentes: Colubridae) from Indochina
Abstract A new species of the genus Gonyosoma Wagler is described from Vietnam and Laos, based on an integrative approach combining morphological and molecular evidence. Gonyosoma iadinum sp. nov. is distinguished from its congeners by a unique combination of diagnostic characters. It differs from its morphologically closest relative, Gonyosoma coeruleum Liu, Hou, Lwin, Wang & Rao, in the structure of the cloacal plate and hemipenes, as well as in significant genetic divergence in the cytochrome b (cyt b) mitochondrial DNA (mtDNA) gene sequences (p > 8.1%). The new species is currently known from central and southern Vietnam and central and southern Laos, where it has been recorded in montane evergreen forests of the Kon Tum-Gia Lai Plateau and the Langbiang Plateau in Vietnam. In Laos, it has been documented in Khammouan Province and the Bolaven Plateau. The species inhabits elevations ranging from 655 to 1,550 m above sea level. Further studies are required to reassess the taxonomic status of the Gonyosoma prasinum complex, particularly in Hainan Island, China. Based on its known distribution and available data, we suggest that the new species should be classified as Least Concern (LC) under the IUCN Red List criteria. We also provide an updated taxonomic key for the Gonyosoma species. Reptilia, Gonyosoma iadinum sp. nov., Vietnam, Laos, Truong Son Range, cloacal plate, morphology, molecular phylogeny, systematics   
Gonyosoma iadinum sp. nov.
Nikolay A. POYARKOV, Andrey M. BRAGIN, Sabira S. IDIIATULLINA, Tuan Anh TRAN, Dac Xuan LE, Patrick DAVID and Tan Van NGUYEN. 2025. A New Species of the Gonyosoma prasinum species complex (Squamata: Serpentes: Colubridae) from Indochina. Zootaxa. 5673(3); 355-384. DOI: doi.org/10.11646/zootaxa.5673.3.2 [2025-08-06]  |
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