“South American” Marsupials from the Late Cretaceous of North America and the Origin of Marsupial Cohorts

2005 ◽  
Vol 12 (3-4) ◽  
pp. 461-494 ◽  
Author(s):  
Judd A Case ◽  
Francisco J. Goin ◽  
Michael O. Woodburne
2011 ◽  
Vol 48 (11) ◽  
pp. 1483-1488 ◽  
Author(s):  
Rubén Somoza

Determining the Late Cretaceous paleomagnetic pole for North America has been difficult because of the lack of suitable rocks of that age in cratonic areas to provide the necessary data. As an alternative, different studies have appealed to paleomagnetic data from rocks in western North America. Using paleopoles from stable areas in neighboring continents, it is suggested that the available Late Cretaceous paleomagnetic record in western North America should be analyzed in terms of rigid body deformations rather than be used to represent the cratonic reference field.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5910 ◽  
Author(s):  
Jessie Atterholt ◽  
J. Howard Hutchison ◽  
Jingmai K. O’Connor

The most complete known North American enantiornithine was collected in 1992 but never formally described. The so-called “Kaiparowits avisaurid” remains one of the most exceptional Late Cretaceous enantiornithine fossils. We recognize this specimen as a new taxon, Mirarce eatoni (gen. et sp. nov.), and provide a complete anatomical description. We maintain that the specimen is referable to the Avisauridae, a clade previously only known in North America from isolated tarsometatarsi. Information from this specimen helps to clarify evolutionary trends within the Enantiornithes. Its large body size supports previously observed trends toward larger body mass in the Late Cretaceous. However, trends toward increased fusion of compound elements across the clade as a whole are weak compared to the Ornithuromorpha. The new specimen reveals for the first time the presence of remige papillae in the enantiornithines, indicating this feature was evolved in parallel to dromaeosaurids and derived ornithuromorphs. Although morphology of the pygostyle and (to a lesser degree) the coracoid and manus appear to remain fairly static during the 65 million years plus of enantiornithine evolution, by the end of the Mesozoic at least some enantiornithine birds had evolved several features convergent with the Neornithes including a deeply keeled sternum, a narrow furcula with a short hypocleidium, and ulnar quill knobs—all features that indicate refinement of the flight apparatus and increased aerial abilities. We conduct the first cladistic analysis to include all purported avisuarid enantiornithines, recovering an Avisauridae consisting of a dichotomy between North and South American taxa. Based on morphological observations and supported by cladistic analysis, we demonstrate Avisaurus to be paraphyletic and erect a new genus for “A. gloriae,” Gettyia gen. nov.


2018 ◽  
Author(s):  
S. Augusta Maccracken ◽  
◽  
Ian M. Miller ◽  
Conrad C. Labandeira

Zootaxa ◽  
2005 ◽  
Vol 932 (1) ◽  
pp. 1 ◽  
Author(s):  
HARRY M. SAVAGE ◽  
R. WILLS FLOWERS ◽  
WENDY PORRAS V.

A new genus, Tikuna, is described based on recent collections of adults and nymphs of Choroterpes atramentum Traver from western Costa Rica. All recent collections are from streams on or near the Nicoya Complex, the oldest geological formation in Lower Central America. Tikuna belongs to a lineage of South American Atalophlebiinae (Leptophlebiidae: Ephemeroptera) whose origin is hypothesized to have been in the late Cretaceous–early Tertiary. Some implications of the distribution of Tikuna for theories on the origin of Costa Rica’s biota are discussed.


2014 ◽  
Vol 51 (7) ◽  
pp. 677-681 ◽  
Author(s):  
Matthew J. Vavrek ◽  
Alison M. Murray ◽  
Phil R. Bell

A recent survey of the middle Cenomanian Dunvegan Formation along the Peace River, Alberta, has yielded a partial skull of a large acipenseriform fish. The fossil was from an animal approximately 5 m in length, based on comparisons with living relatives. Though incomplete, this represents an important record of mid-Cretaceous fish from northern North America, as formations of this age are virtually unexplored in northern regions. This fossil is the oldest acipenserid from North America, and one of the most northerly known.


2011 ◽  
Vol 83 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Juan D. Porfiri ◽  
Jorge O. Calvo ◽  
Domenica dos Santos

Here we report on a new small deinonychosaurian theropod, Pamparaptor micros gen. et sp. nov., from the Late Cretaceous of Patagônia, Argentina. Pamparaptor micros exhibits a pedal structure previously unknown among South Américan deinonychosaurians. The new material provides new evidence about the morphology and taxonomic diversity of Patagônian deinonychosaurs. Pamparaptor is the smaller non-avialae Patagônian deinonychosaur, probably with about 0.50-0.70 meters, long. The pedal construction resembles, that of Troodontid or basal Dromaeosaurids. Nevertheless, up to now, we considered Pamparaptor a peculiar Patagônian Dromaeosaurid with troodontid-like pes.


2021 ◽  
Vol 8 (10) ◽  
Author(s):  
Cecily S. C. Nicholl ◽  
Eloise S. E. Hunt ◽  
Driss Ouarhache ◽  
Philip D. Mannion

Notosuchians are an extinct clade of terrestrial crocodyliforms with a particularly rich record in the late Early to Late Cretaceous (approx. 130–66 Ma) of Gondwana. Although much of this diversity comes from South America, Africa and Indo-Madagascar have also yielded numerous notosuchian remains. Three notosuchian species are currently recognized from the early Late Cretaceous (approx. 100 Ma) Kem Kem Group of Morocco, including the peirosaurid Hamadasuchus rebouli . Here, we describe two new specimens that demonstrate the presence of at least a fourth notosuchian species in this fauna. Antaeusuchus taouzensis n. gen. n. sp. is incorporated into one of the largest notosuchian-focused character-taxon matrices yet to be compiled, comprising 443 characters scored for 63 notosuchian species, with an increased sampling of African and peirosaurid species. Parsimony analyses run under equal and extended implied weighting consistently recover Antaeusuchus as a peirosaurid notosuchian, supported by the presence of two distinct waves on the dorsal dentary surface, a surangular which laterally overlaps the dentary above the mandibular fenestra, and a relatively broad mandibular symphysis. Within Peirosauridae, Antaeusuchus is recovered as the sister taxon of Hamadasuchus . However, it differs from Hamadasuchus with respect to several features, including the ornamentation of the lateral surface of the mandible, the angle of divergence of the mandibular rami, the texture of tooth enamel and the shape of the teeth, supporting their generic distinction. We present a critical reappraisal of the non-South American Gondwanan notosuchian record, which spans the Middle Jurassic–late Eocene. This review, as well as our phylogenetic analyses, indicate the existence of at least three approximately contemporaneous peirosaurid lineages within the Kem Kem Group, alongside other notosuchians, and support the peirosaurid affinities of the ‘trematochampsid’ Miadanasuchus oblita from the Maastrichtian of Madagascar. Furthermore, the Cretaceous record demonstrates the presence of multiple lineages of approximately contemporaneous notosuchians in several African and Madagascan faunas, and supports previous suggestions regarding an undocumented pre-Aptian radiation of Notosuchia. By contrast, the post-Cretaceous record is depauperate, comprising rare occurrences of sebecosuchians in north Africa prior to their extirpation.


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