 Subjects -> PALEONTOLOGY (Total: 43 journals)
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- An updated suprageneric classification of planktic foraminifera after
growing evidence of multiple benthic-planktic transitions
Authors: Ignacio Arenillas, José Antonio Arz, Vicente Gilabert
Pages: 1 - 34
Abstract: Planktic foraminifera have traditionally been classified within a single order: Globigerinida. However, recent phylogenetic studies, both molecular and stratophenetic, are evidencing the polyphyletic origin of planktic foraminifera from several benthic ancestors. At least four independent events of benthic-planktic transition have been identified. One of them occurred after the Cretaceous–Paleogene boundary mass extinction, originating the first Cenozoic globigerinids. Another three occurred in the Mesozoic, originating three groups of planktic foraminifera (globotruncanids, heterohelicids and guembelitriids) not related phylogenetically to each other or to current globigerinids. These findings make it necessary to carry out an exhaustive review of their suprageneric systematics, mainly at the order level. Here we propose a new, more natural classification, grouping them into four orders: Globigerinida, Heterohelicida, Globotruncanida n. ord., and Guembelitriida n. ord. To better reflect the diversity and phylogeny of planktic foraminifera, we have also defined two new superfamilies: Abathomphaloidea n. superfam. and Parvularugoglobigerinoidea n. superfam., and one new family: Parvularuglobigerinidae n. fam.
PubDate: 2022-06-27
DOI: 10.7203/sjp.22189
Issue No: Vol. 37, No. 1 (2022)
- The axial skeleton of Brachyodus onoideus (Mammalia, Anthracotheriidae):
taxonomic and functional implications
Authors: Martin Pickford
Pages: 35 - 52
Abstract: Vertebrae of Brachyodus onoideus from Europe have never been described, yet several specimens have been curated in diverse museums for more than a century. The importance of the cervical vertebrae lies in the fact that they reveal that this species possessed a moderately elongated neck that in neutral posture was oriented upwards, somewhat as in some extant artiodactyls (Okapi, Eland and camels), unlike the low-slung head and neck posture of the two extant genera of hippopotamuses. The sacrum of Brachyodus is markedly different from those of Hippopotamus and Choeropsis. In morpho-functional terms it is closer to those of large ruminants and equids, indicating the possession of a less muscular tail than in hippos which wag their tails energetically during defecation.
PubDate: 2022-06-27
DOI: 10.7203/sjp.24118
Issue No: Vol. 37, No. 1 (2022)
- Estudio morfológico de los restos mandibulares del género Canis en el
yacimiento holoceno de El Portalón (Sierra de Atapuerca). Implicaciones
en la aparición del perro en la prehistoria
Authors: Raquel Blázquez-Orta, Laura Rodríguez, Marián Galindo-Pellicena, Nuria García
Pages: 53 - 68
Abstract: El Portalón de Cueva Mayor es uno de los yacimientos arqueo-paleontológicos holocenos más importantes de la Meseta Norte y forma parte del complejo kárstico de la Sierra de Atapuerca (Burgos). La Edad del Bronce constituye un importante legado arqueo-paleontológico en la región central de la Península Ibérica. En este período se registran la mayor parte de los procesos de domesticación de fauna silvestre. Una de las especies propuestas para haber sido domesticada en este contexto es el lobo (Canis lupus). La falta de evidencias de un haplotipo específico en perros que permita distinguirlos a nivel molecular como ocurre con ganado bovino y caprino, hace imprescindible que el problema se aborde desde una perspectiva morfométrica. Por tanto, el objetivo de este trabajo es analizar características morfométricas en mandíbulas del género Canis del Bronce inicial–medio, y compararlas con perros y lobos modernos, con el objetivo de aportar conocimiento sobre el proceso de evolución de la forma silvestre a doméstica de la especie Canis lupus. Los resultados sugieren que las mandíbulas de El Portalón son más pequeñas en tamaño que la de los lobos modernos, sin embargo, conservan ciertas morfologías primitivas presentes en lobos en la rama mandibular y el M1.
PubDate: 2022-06-27
DOI: 10.7203/sjp.24124
Issue No: Vol. 37, No. 1 (2022)
- Systematics, distribution and paleoecology of the genera Genocidaris
Agassiz, 1869 and Arbacina Pomel, 1869 (Trigonocidaridae, Echinoidea)
Authors: Enrico Borghi, Ildefonso Bajo
Pages: 69 - 86
Abstract: The relationship among members of the echinoid genera Genocidaris and Arbacina (family Trigonocidaridae) is studied. Distinctive morphological characters of these two genera are discussed, based on recent specimens from the Caribbean and the Mediterranean and on fossils collected from 34 Miocene, Pliocene and Pleistocene European localities. Geographic and biostratigraphic distributions of the two genera and their paleoecological requirements are reported. Based on this analysis, Arbacina is considered a junior synonym of the genus Genocidaris.
PubDate: 2022-06-27
DOI: 10.7203/sjp.24204
Issue No: Vol. 37, No. 1 (2022)
- Is Onychodontida (Osteichthyes, Sarcopterygii) monophyletic' Assessing
discordant phylogenies with quantitative comparative cladistics
Authors: Maria Ciudad Real, Jorge Mondéjar-Fernández, Daniel Vidal, Héctor Botella
Pages: 87 - 100
Abstract: Onychodontida (Osteichthyes, Sarcopterygii) was an extinct group of Devonian predatory marine fishes, representing an early branch in sarcopterygian evolution, and currently considered closely related to coelacanths (Actinistia). Due to their limited fossil record, the relationships of onychodonts within sarcopterygians, and whether all taxa traditionally considered as onychodonts form a clade, are still unclear. Here we review the most recent phylogenetic analyses by comparing their data matrices using recent tools and methodology in quantitative comparative cladistics in order to evaluate the source of discrepancies in the different datasets and provide possible practical solutions to test the monophyly of Onychodontida. These discrepancies range from the ambiguous formulation of character statements and character states to the poor preservation of certain fossils, which make interpretation of character states difficult. Understudied but highly complete fossil specimens are also a source of missing data that have an impact in discording tree topologies. In-depth analysis and description of these specimens is needed to improve the resolution of future phylogenetic analyses. Finally, we propose a formal stem-based phylogenetic defi nition for Onychodontida.
PubDate: 2022-06-27
DOI: 10.7203/sjp.24256
Issue No: Vol. 37, No. 1 (2022)
- Biostratigraphy of the Ribota and Huérmeda formations (Cambrian Series 2)
in the Comarca del Aranda (Zaragoza province), Iberian Chains (NE Spain)
Authors: Alexandre Sepúlveda, Eladio Liñan, Juan B. Chirivella, José Antonio Gámez Vintaned, Rodolfo Gozalo
Pages: 101 - 122
Abstract: This article presents a detailed biostratigraphic analysis of the Cambrian Series 2 Ribota and Huérmeda formations of four sections of the Iberian Chains (NE Spain), and a systematic study of their trilobite faunas. We identified four major assemblages: two in the middle part of the Ribota Formation, one at the base of the Huérmeda Formation and one at the top of the Huérmeda Formation. The studied species permit the assignment of these formations to the middle and upper Marianian and probably lower Bilbilian stages in the regional stratigraphic chart for the Iberian Peninsula, which correlates with an interval around the Cambrian Stage 3–4 boundary. The assemblages exhibit a great correlation potential with the presence of Termierella and the first figured material of Andalusiana from the Iberian Chains, two characteristic taxa of the Marianian of the Ossa-Morena Zone, having been also recorded from the Central Iberian Zone and Morocco. In addition, specimens tentatively assigned to Hebediscus are recorded for the first time from the region, a taxon with a wide geographic distribution which allows a good international correlation in the Cambrian Series 2.
PubDate: 2022-06-27
DOI: 10.7203/sjp.24492
Issue No: Vol. 37, No. 1 (2022)
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