scholarly journals Equatorial pliosaurid from Venezuela marks the youngest South American occurrence of the clade

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dylan Bastiaans ◽  
Daniel Madzia ◽  
Jorge D. Carrillo-Briceño ◽  
Sven Sachs

AbstractPliosaurids were the dominant macropredators in aquatic environments at least since the Middle Jurassic until their extinction in the early Late Cretaceous. Until very recently, the Cretaceous record of Pliosauridae has been poor and difficult to interpret from the taxonomic and phylogenetic perspective. Despite that the knowledge of Cretaceous pliosaurids improved in recent years, numerous aspects of their evolutionary history still remain only poorly known. Here, we report the first pliosaurid material from Venezuela. The taxon is most likely earliest Cenomanian in age, thus representing the youngest occurrence of Pliosauridae from South America. The Venezuelan taxon is based on a well-preserved tooth crown whose morphology and outer enamel structural elements appear to resemble especially those observable in the giant pliosaurid Sachicasaurus vitae from the Lower Cretaceous of Colombia. The new discovery extends the pliosaurid record on the continent by more than 10 million years and likely marks the southernmost Upper Cretaceous occurrence of Pliosauridae, worldwide. We also briefly discuss the affinities of the enigmatic Venezuelan elasmosaurid Alzadasaurus tropicus and highlight similarities to elasmosaurids from the Western Interior Seaway.

2017 ◽  
Vol 67 (3) ◽  
pp. 393-403 ◽  
Author(s):  
Daniel Madzia ◽  
Marcin Machalski

AbstractBrachauchenine pliosaurids were a cosmopolitan clade of macropredatory plesiosaurs that are considered to represent the only pliosaurid lineage that survived the faunal turnover of marine amniotes during the Jurassic- Cretaceous transition. However, the European record of the Early to early Late Cretaceous brachauchenines is largely limited to isolated tooth crowns, most of which have been attributed to the classic Cretaceous taxon Polyptychodon. Nevertheless, the original material of P. interruptus, the type species of Polyptychodon, was recently reappraised and found undiagnostic. Here, we describe a collection of twelve pliosaurid teeth from the upper Albian-middle Cenomanian interval of the condensed, phosphorite-bearing Cretaceous succession at Annopol, Poland. Eleven of the studied tooth crowns, from the Albian and Cenomanian strata, fall within the range of the morphological variability observed in the original material of P. interruptus from the Cretaceous of England. One tooth crown from the middle Cenomanian is characterized by a gently subtrihedral cross-section. Similar morphology has so far been described only for pliosaurid teeth from the Late Jurassic and Early Cretaceous. Even though it remains impossible to precisely settle the taxonomic distinctions, the studied material is considered to be taxonomically heterogeneous.


2018 ◽  
Vol 93 (2) ◽  
pp. 278-290
Author(s):  
J. Mark Erickson

AbstractIn midcontinent North America, the Fox Hills Formation (Upper Cretaceous, upper Maastrichtian) preserves the last marine faunas in the central Western Interior Seaway (WIS).Neritoptyx hogansoninew species, a small littoral snail, exhibited allometric change from smooth to corded ornament and rounded to shouldered shape during growth. Specimens preserve a zig-zag pigment pattern that changes to an axial pattern during growth.Neritoptyx hogansoninew species was preyed on by decapod crustaceans, and spent shells were occupied by pagurid crabs. Dead mollusk shells, particularly those ofCrassostrea subtrigonalis(Evans and Shumard, 1857), provided a hard substrate to which they adhered on the Fox Hills tidal flats. This new neritimorph gastropod establishes a paleogeographic and chronostratigraphic proxy for intertidal conditions on the Dakota Isthmus during the late Maastrichtian. Presence of a neritid extends the marine tropical/temperate boundary in the WIS northward to ~44° late Maastrichtian paleolatitude. Late Maastrichtian closure of the isthmus subsequently altered marine heat transfer by interrupting northward flow of tropical currents from the Gulf Coast by as much as 1 to 1.5 million years before the Cretaceous ended.UUID:http://zoobank.org/3ba56c07-fcca-4925-a2f0-df663fc3a06b


2002 ◽  
Vol 76 (2) ◽  
pp. 265-270 ◽  
Author(s):  
Geerat J. Vermeij ◽  
Frank P. Wesselingh

Two neogastropod species occur in brackish intervals in the Pebas Formation (late Middle to early Late Miocene) of Peru and Colombia in western Amazonia. Purpura woodwardi Roxo, 1924, is assigned to Melongena Schumacher, 1817 (Melongenidae), and ?Nassarius reductus (Nassariidae) is recognized as a new species. These gastropods are among the very few marine invaders in the otherwise freshwater Pebas fauna. The small number of marine to freshwater transitions among South American molluscs contrasts with the situation among South American fishes and southeast Asian molluscs. It may be related to seasonal fluctuations in water level and anoxia in present-day South American freshwater environments, as well as to predation and productivity.


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.


Genomics ◽  
2020 ◽  
Vol 112 (5) ◽  
pp. 3511-3517
Author(s):  
Yanjun Shen ◽  
Na Yang ◽  
Zhihao Liu ◽  
Qiliang Chen ◽  
Yingwen Li

2013 ◽  
Vol 13 (4) ◽  
pp. 77-89 ◽  
Author(s):  
Aline Cristina Martins ◽  
Isabel Alves-dos-Santos

Floral oils as reward to pollinators occur in eleven plant families and appeared at least 28 times in the evolutionary history of flowering plants. They are produced in epithelial or tricomatic glands and collected by oil bee visitors. The present paper focuses on floral-oil-producing species of Plantaginaceae, a Neotropical group namely Angelonia clade. This group comprises around 40 described species in the genera Angelonia, Basistemon, Monttea, Monopera and the oil-less Melosperma. We present a revision of all species of the Angelonia clade, their geographical distribution, resources offered to pollinators and records of flower visitors, especially oil-collecting bees. These plants rely only on oil-collecting species in the tribe Centridini and Tapinotaspidini for a successful pollination, being the interaction between both partners an especial case of bee/flower adaptation in Neotropical region. Some bee species depend only on the oil of Plantaginaceae flowers to survive, while others can collect on several floral oil sources. The pollinating bees explore the oil glands located in sacs using specialized hairs in the forelegs. With this study, we hope to inspire further research relating to this fascinating group of plants, in which most species are rare and occur in highly endangered habitats in South American open vegetation biomes.


Author(s):  
Jerzy Dzik

ABSTRACTFour kinds of robust elements have been recognised in Amorphognathus quinquiradiatus Moskalenko, 1977 (in Kanygin et al. 1977) from the early Late Ordovician of Siberia, indicating that at least 17 elements were present in the apparatus, one of them similar to the P1 element of the Early Silurian Distomodus. The new generic name Moskalenkodus is proposed for these conodonts with a pterospathodontid-like S series element morphology. This implies that the related Distomodus, Pterospathodus and Gamachignathus lineages had a long cryptic evolutionary history, probably ranging back to the early Ordovician, when they split from the lineage of Icriodella, having a duplicated M location in common. The balognathid Promissum, with a 19-element apparatus, may have shared ancestry with Icriodella in Ordovician high latitudes, with Sagittodontina, Lenodus, Trapezognathus and Phragmodus as possible connecting links. The pattern of the unbalanced contribution of Baltoniodus element types to samples suggests that duplication of M and P2 series elements may have been an early event in the evolution of balognathids. The proposed scenario implies a profound transformation of the mouth region in the evolution of conodonts. The probable original state was a chaetognath-like arrangement of coniform elements; all paired and of relatively uniform morphology. This was modified at the origin of protopanderodontids by the introduction of a medial S0 element, which resulted in the separation of the exposed unit of M and S series elements from the P series elements hidden in the throat. A rotation of the S series elements to an almost horizontal position in early prioniodontids may have promoted duplication of the M element pair. In Gamachignathus, Icriodella and Pterospathodus lineages, these elements are differentiated morphologically. Subsequent anteriorward bending of the P element series caused duplication of the balognathid P2 element pair, but they remained undifferentiated, even in the otherwise elaborate Promissum. The whole clade of conodonts with supernumerary element pairs in the apparatus has its roots in high latitudes of the Ordovician.


2020 ◽  
Vol 116 ◽  
pp. 104619
Author(s):  
Tamara El Hossny ◽  
Sibelle Maksoud ◽  
Dany Azar ◽  
Pierre Abi Saad ◽  
Lionel Cavin

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