126 research outputs found
Neochelys sp. (Chelonii, Erymnochelyinae), from Silveirinha, early Eocene, Portugal
Constituted of isolated fragments with a smooth decoration, the turtle material from Silveirinha is examined in order to define
its sure belonging to Neochelys, by comparison with other smooth turtles which may be present during the Palaeogene of Europe (freshwater Testudinidae, Erymnochelyinae, Bothremydidae). The elements are compared with the already known Neochelys species of the Eocene European localities. Questions are made about the possible geographical migrations of turtles between South and North during the early Eocene of western Europe. The phyletic relationships cannot be established but the species, seeming new and one of the more primitive as a whole (after the preserved elements), is the older from the Iberian Peninsula
La tortuga pre-Podocnemidid más antigua (Chelonii, Pleurodira), Cretácico inferior, estado de Ceará, Brasil, y su entorno
A new form of a chelonian Pleurodira is described, Brasilemys josai, n.g., n. sp. Its phyletic position is examined with respect to previously established phylogenies. It is situated with respect to recently described taxa whose position is not yet clearly established, such as Dortokidae, Hamadachelys and an unnamed form from Araripe. In the Podocnemidoidea, Brasilemys n.g. represents the earliest known specimen of the Podocnemidoidae, immediately after the divergence of the Bothremydidae. It is part of the formidable radiation in the Pelomedusoides which occurs during the early Cretaceous when South America separated from Africa. The turtle fauna in Chapada do Araripe includes four freshwater Pelomedusoides, samples of the ancient northern Gondwana fauna, as well as a cryptodiran turtle, possibly a littoral form belonging to a more cosmopolitan group. In agreement with the stratigrahical data as well as data from the study of fossil crocodiles, this turtle fauna dates between the late Aptian fauna of Gadoufaoua (Niger) and the late Albian-early Cenomanian fauna from the Sahara.
Key words: Chelonians, New taxon, Phyletic relationships, Cretaceous, Brasil, Palaeoecolgical and Stratigraphical considerations.Se describe una nueva forma de tortuga pleurodira, Brasilemys josai, n.g., n. sp. Su posición filética se examina en relación con las filogenias establecidas anteriormente. Se sitúa también Brasilemys n.g. en relación con algunas formas recientemente descritas y aún no bien posicionadas en la filogenia de los Pleurodira, como son los Dortokidae, Hamadachelys y otra forma de la Chapada do Araripe sin nombre. En los Podocnemidoidea, Brasilemys n.g. aparece como el primer representante de los Podocnemidoidae, inmediatamente después de la derivación de los Bothremydidae. La aparición de este nuevo género forma parte de la extraordinaria radiación que ocurrió en los Pelomedusoides al inicio del Cretácico, cuando se separaron América del Sur y África. La fauna de tortugas de la Chapada do Araripe incluye cuatro taxones de Pelomedusoides de agua dulce, representantes de la fauna de la parte norte del antiguo continente Gondwana, además de una tortuga cryptodira, posiblemente litoral y perteneciente a un grupo más cosmopolita. De acuerdo con los datos de la estratigrafía y con los del estudio de los cocodrilos fósiles, la edad de la fauna de tortugas se situaría entre el Aptiense superior de Gadoufaoua (Niger) y el Albiense superior - base del Cenomaniense del Sáhara.
Palabras clave: Quelonios, Nuevo taxón, Relaciones filéticas, Cretácico, Brasil, Consideraciones paleoecológicas y estratigráficas
Phylogeny, biogeography and diversification patterns of side-necked turtles (Testudines: Pleurodira)
Pleurodires or side-necked turtles are today restricted to freshwater environments of South America, Africa– Madagascar and Australia, but in the past they were distributed much more broadly, being found also on Eurasia, India and North America, and marine environments. Two hypotheses were proposed to explain this distribution; in the first, vicariance would have shaped the current geographical distribution and, in the second, extinctions constrained a previously widespread distribution. Here, we aim to reconstruct pleurodiran biogeographic history and diversification patterns based on a new phylogenetic hypothesis recovered from the analysis of the largest morphological dataset yet compiled for the lineage, testing which biogeographical process prevailed during its evolutionary history. The resulting topology generally agrees with previous hypotheses of the group and shows that most diversification shifts were related to the exploration of new niches, e.g. littoral or marine radiations. In addition, as other turtles, pleurodires do not seem to have been much affected by either the Cretaceous– Palaeogene or the Eocene–Oligocene mass extinctions. The biogeographic analyses highlight the predominance of both anagenetic and cladogenetic dispersal events and support the importance of transoceanic dispersals as a more common driver of area changes than previously thought, agreeing with previous studies with other non-turtle lineages.Fil: Ferreira, Gabriel S.. Universidade de Sao Paulo; Brasil. Senckenberg Centre For Human Evolution And Palaeoenvironment; Alemania. Universität Tübingen; AlemaniaFil: Bronzati Filho, Mario. Bayerische Staatssammlung für Paläontologie und Geologie; AlemaniaFil: Langer, Max C.. Universidade de Sao Paulo; BrasilFil: Sterli, Juliana. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Cheirogaster sp. (O. Testudines, Fam. Testudinidae, Geochelone sl.) du Paléogène de Naia, Tondela et l’âge du gisement
A land tortoise from a new locality at Naia, Tondela, is described. It is to be reported either to an advanced form of the genus Hadrianus or to an archaic representative of Cheirogaster; it may be included in the comprehensive genus Geochelone s.l., excluding however Ergilemys and its descendants. There is a strong possibility in favour of Cheirogaster. Testudo must also be excluded. It is not possible to classify this specimen at species'level. Our specimen does agree best with Upper Eocene Testudinidae and with some Lower Oligocene ones.
Its age is certainly not Upper Oligocene or later, nor Lower and Middle Eocene.
This datation is not opposed to the age of the fossiliferous clays of Naia as supposed by correlation with another locality - Côja, about 30 km to the South - which yielded an assemblage of mammals whose Ludian (Upper Bartonian s.l.) age seems well established. Naia and Côja's fossil-bearing clays must be nearly synchronous; their origin is well in place among the phenomena related to the surrection of iberian Central Chain during paroxysmal phase of pyrenean orogenesis
Le Crétacé terminal de Beira Litoral, Portugal: remarques stratigraphiques et écologiques,étude complémentaire de Rosasia soutoi (Chelonii, Bothremydidae)
The synthetic study of the uppermost Cretaceous of the Beira Litoral (fauna, flora) confirms its upper Campanian-Maastrichtian age. It shows the presence of a tropical to subtropical climate in an area constituted by a low coastal plain only occasionally linked to the sea, saturated with fresh water and possessing accordingly, a predominantely freshwater fauna (Viso, Aveiro); this plain changed towards the interior into a drier more forested zone with a more abundant terrestrial fauna which includes mammals (Taveiro).
A thorough study of the chelonian Rosasia, abundant on the coastal plain, was made possible thanks to the discovery of a skull: it demonstrates that the genus belongs to the family Bothremydidae, revalided here. The composition of this family is presented, its phylogenetic and paleobiogeographic relation with the other pleurodires are analyzed, and its diagnosis established. The family is constituted of three groups; Rosasia belongs to one of these, the Bothremys group
Découverte de «Plesiochelys», Chélonien marin-littoral, dans le Kimméridgien d’Alcobaça, Portugal
The presence of Craspedochelys (Plesiochelys s.l.) at Romão, Portugal, indicates that, in that country, the Thalassemydid dispersal began with the first occurrences of the group in Europe, in the late Kimmeridgian: communications existed between septentrional, atlantic and mesogean seas. The review of the family is considered
The turtles from the upper Eocene, Osona County (Ebro Basin, Catalonia, Spain): new material and its faunistic and environmental context
Eochelone voltregana n. sp. is a new marine cryptodiran cheloniid
found at the Priabonian levels (latest Eocene) of the Vespella marls member of
the Vic–Manlleu marls formation. It is the second cheloniid from Santa
Cecília de Voltregà (Osona County, Spain), the first one being
Osonachelus decorata from the same formation. Shell parameters
indicate that the new species belongs to a branch of sea turtles including
the Eocene Anglo–Franco–Belgian forms Argillochelys,
Puppigerus and Eochelone (the shell of the latter was studied here
for the first time) as well as Glarichelys from the Oligocene of
Switzerland, all of them predating the worldwide living Miocene genera. The
description of two other more littoral–continental Eocene species is given:
Trionyx sp., from an older layer of the same formation; and the
podocnemidid erymnochelyine,
Cordichelys from a more basal layer of a middle Eocene (Lutetian)
formation. The last one is identified as the only evidence of the
Shweboemys subgroup in the European record, being distinct from the
other known Osona County pleurodire Eocenochelus farresi, which is a
member of the Erymnochelys group (same subfamily), from the younger
Priabonian Sant Martí Xic layer. Thus, an update on the marine turtle
fauna of the eastern Ebro Basin that variably opened in the east during
Eocene times is provided. The turtles of Osona County belong to two suborders
and five genera with three new species and extend the known distribution of
their families (LSID
urn:lsid:zoobank.org:act:48CE8676-7B82-4EF2-8165-27BEE90129F2).</p
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