scholarly journals Welwitschioid diversity in the Early Cretaceous: evidence from fossil seeds with pollen from Portugal and eastern North America

Grana ◽  
2014 ◽  
Vol 53 (3) ◽  
pp. 175-196 ◽  
Author(s):  
Else Marie Friis ◽  
Kaj Raunsgaard Pedersen ◽  
Peter R. Crane
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
Eastern North America ◽  
Fossil Seeds

scholarly journals Extinct Taxa of Exotestal Seeds Close to Austrobaileyales and Nymphaeales From the Early Cretaceous of Portugal

2018 ◽  
Vol 74 (1-2) ◽  
pp. 135-158 ◽  
Author(s):  
Else Marie Friis ◽  
Peter R. Crane ◽  
Kaj Raunsgaard Pedersen
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
Seed Coat ◽  
Close Relationships ◽  
Surface Pattern ◽  
Eastern North America ◽  
New Genera ◽  
Jigsaw Puzzle ◽  
Nutritive Tissue ◽  
Fossil Seeds

Early Cretaceous mesofossil floras from Portugal and North America include a surprising diversity of small, bitegmic angiosperm seeds with a hard exotestal seed coat. This study describes six different kinds of these seeds from three Portuguese mesofossil localities; Vale de Agua, Torres Vedras, and especially from Famalicão, which has yielded a flora exceptionally rich in exotestal seeds. All the seeds are almost smooth with a characteristic jigsaw puzzle-shaped surface pattern that is formed from the strongly undulate anticlinal walls of the sclerenchyma cells that comprise the exotesta. Several specimens have internal details preserved, including remains of a cellular nutritive tissue interpreted as endosperm, and a tiny embryo with two rudimentary cotyledons. Based on differences in details of the seed coat, and configuration of hilum and micropyle, the fossil seeds are assigned to six new genera, as six new species: Gastonispermum portugallicum gen. et sp. nov., Pazlia hilaris gen. et sp. nov., Pazliopsis reyi gen. et sp. nov., Reyispermum parvum gen. et sp. nov., Lusitanispermum choffatii gen. et sp. nov. and Silutanispermum kvacekiorum gen. et sp. nov. The characteristic exotestal cells with undulate anticlinal walls, details of the hilar and micropylar region, together with the tiny dicotyledonous embryos with rudimentary cotyledons, suggest close relationships to seeds of Nitaspermum and Tanispermum described previously from Early Cretaceous mesofossil floras from eastern North America. These exotestal seeds from Portugal and North America indicate the presence of diverse extinct early angiosperms close to the lineages that today include extant Austrobaileyales and Nymphaeales.

New multituberculate mammal from the Early Cretaceous of eastern North America

2013 ◽  
Vol 50 (3) ◽  
pp. 315-323 ◽  
Author(s):  
Richard L. Cifelli ◽  
Cynthia L. Gordon ◽  
Thomas R. Lipka
Keyword(s):  
North America ◽  
Iberian Peninsula ◽  
Early Cretaceous ◽  
North American ◽  
Lower Cretaceous ◽  
Late Jurassic ◽  
Relative Length ◽  
Central Position ◽  
Eastern North America ◽  
The North

Multituberculates, though among the most commonly encountered mammalian fossils of the Mesozoic, are poorly known from the North American Early Cretaceous, with only one taxon named to date. Herein we describe Argillomys marylandensis, gen. et sp. nov., from the Early Cretaceous of Maryland, based on an isolated M2. Argillomys represents the second mammal known from the Arundel Clay facies of the Patuxent Formation (Lower Cretaceous: Aptian). Though distinctive in its combination of characters (e.g., enamel ornamentation consisting of ribs and grooves only, cusp formula 2:4, presence of distinct cusp on anterobuccal ridge, enlargement of second cusp on buccal row, central position of ultimate cusp in lingual row, great relative length), the broader affinities of Argillomys cannot be established because of non-representation of the antemolar dentition. Based on lack of apomorphies commonly seen among Cimolodonta (e.g., three or more cusps present in buccal row, fusion of cusps in lingual row, cusps strongly pyramidal and separated by narrow grooves), we provisionally regard Argillomys as a multituberculate of “plagiaulacidan” grade. Intriguingly, it is comparable in certain respects to some unnamed Paulchoffatiidae, a family otherwise known from the Late Jurassic – Early Cretaceous of the Iberian Peninsula.

scholarly journals Redescription of Arundel formation Ornithomimosaur material and a reinterpretation of Nedcolbertia justinhofmanni as an “Ostrich Dinosaur”: Biogeographic implications

2016 ◽  
Author(s):  
Chase Doran Brownstein
Keyword(s):  
United States ◽  
North America ◽  
Early Cretaceous ◽  
Fossil Record ◽  
East Coast ◽  
The United States ◽  
Eastern North America ◽  
New Taxon ◽  
Western North America ◽  
The Past

The fossil record of dinosaurs from the Early Cretaceous of eastern North America is scant, and only a few sediments to the east of the continent are fossiliferous. Among them is the Arundel Formation of the east coast of the United States, which has produced among the best dinosaur faunas known from the Early Cretaceous of eastern North America. The diverse dinosaur fauna of this formation has been thoroughly discussed previously, but few of the dinosaur species originally described from the Arundel are still regarded as valid genera. Much of the Arundel material is in need of review and redescription. Among the fossils of dinosaurs from this formation are those referred to ornithomimosaurs. Here, I redescribe ornithomimosaur remains from the Arundel Formation which may warrant the naming of a new taxon of dinosaur. These remains provide key information on the theropods of the Early Cretaceous of Eastern North America. The description of the Arundel material herein along with recent discoveries of basal ornithomimosaurs in the past 15 years has allowed for comparisons with the coelurosaur Nedcolbertia justinhofmanni, suggesting the latter animal was a basal ornithomimosaurian dinosaur rather than a “generalized” coelurosaur. Comparisons between the Arundel ornithomimosaur and similar southeast Asian ornithomimosaurian material as well as ornithomimosaur remains from western North America suggest that a lineage of ornithomimosaurs with a metatarsal condition intermediate between that of basal and derived ornithomimosaurs was present through southeast Asia into North America, in turn suggesting that such animals coexisted with genera having a more primitive metatarsal morphology as seen in N. justinhofmanni.

scholarly journals Rightcania and Kvacekispermum: Early Cretaceous Seeds From Eastern North America and Portugal Provide Further Evidence of the Early Chloranthoid Diversification

2018 ◽  
Vol 74 (1-2) ◽  
pp. 65-76 ◽  
Author(s):  
Else Marie Friis ◽  
Peter R. Crane ◽  
Kaj Raunsgaard Pedersen
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
Seed Coat ◽  
Outer Surface ◽  
General Structure ◽  
Single Species ◽  
Eastern North America ◽  
New Genera ◽  
Nutritive Tissue ◽  
Crystal Cells

Abundant flowers, fruits, seeds and stamens that are closely related to extant Chloranthaceae have been reported from the Early Cretaceous floras of Portugal. Among these are small berries with endotestal seeds assigned to the extinct genera Canrightia and Canrightiopsis. Here we describe two new genera, each including a single species, based on fossil fruits and seeds from the Early Cretaceous of eastern North America and Portugal. Both genera have pendent, orthotropous, bitegmic and endotestal ovules/seeds, in which the endotesta consists of a layer of cubic to palisade-shaped crystal cells with endoreticulate fibrous infillings, a combination of features that also characterize Canrightia and Canrightiopsis and that among extant angiosperms are known only for members of the Chloranthaceae. Rightcania kvacekii gen. et sp. nov. from the early to middle Albian Puddledock mesofossil flora of Virginia, USA, is the first representative in the Early Cretaceous floras of North America of a chloranthaceous fossil related to Canrightia and Canrightiopsis. It has three- to five-seeded fruits very similar to fruits and seeds of Canrightia, also with a pronounced tegmen that probably functioned as a nutritive tissue for the developing embryo. Fruits and seeds of Rightcania are larger than those of Canrightia, and also differ in details of the seed coat. Kvacekispermum rugosum gen. et sp. nov. is rare in the late Aptian to early Albian Portuguese mesofossil flora from Vale de Água. It differs from Canrightiopsis in the coarsely rugulate outer surface of the endotesta and its larger size, but is closely similar in the general structure of seed coat and nutritive tissue. Together, Rightcania and Kvacekispermum provide further evidence of the early diversity achieved by chloranthoid angiosperms before the end of the Early Cretaceous.

scholarly journals Geminispermum, an Early Cretaceous (early–middle Albian) cupulate unit from the angiosperm-dominated Puddledock flora of eastern North America

2019 ◽  
Vol 59 (2) ◽  
pp. 229-239 ◽  
Author(s):  
Else Marie Friis ◽  
Peter R. Crane ◽  
Kaj Raunsgaard Pedersen
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
New Genus ◽  
Eastern North America ◽  
Seed Plant ◽  
New Genus And Species ◽  
Reproductive Structures ◽  
Short Transverse ◽  
Reproductive Unit ◽  
The One

Abstract A new genus and species, Geminispermum virginiense, is described based on a well-preserved coalified cupulate reproductive unit recovered from the Early Cretaceous (early–middle Albian) Puddledock locality, Virginia, U.S.A. The reproductive unit is bisymmetrical and consists of an axis that bifurcates into two cupule-bearing stalks, each in the axil of a bract. Each cupule stalk bears a single non-valvate cupule recurved towards the center of the reproductive unit. The cupule opens distally by a short transverse slit with a distinct upper margin. Each cupule almost completely encloses a single orthotropous seed that is free from the cupule except at the base. The nucellus is also free from the integument except at the basal point of attachment. Geminispermum combines features of the ovulate structures of Caytoniales, Umkomasiales (= Corystospermales, including Doyleales) and Petriellales, but cannot be included in any of these existing orders as they are currently understood. The recurved, closed, non-valvate cupules are particularly similar to those of Caytonia, Petriellaea and Reymanownaea in external morphology, but differ in being one-seeded. The cupules of Geminispermum differ from the one-seeded cupules of Umkomasiales in being non-valvate and in having only a single cupule per bract. Geminispermum is perhaps most similar to the one- or two-seeded non-valvate cupules of Ktalenia from the Early Cretaceous of Argentina, but Ktalenia is poorly preserved, details of cupule architecture are uncertain, and the cupules appear to be associated with a single strongly dissected bract. Geminispermum is currently the only unequivocal seed plant cupule recovered from the Early Cretaceous Potomac Group and is distinct from all previously described cupulate reproductive structures.

Carpestella lacunata gen. et sp. nov., a New Basal Angiosperm Flower from the Early Cretaceous (Early to Middle Albian) of Eastern North America

2008 ◽  
Vol 169 (7) ◽  
pp. 890-898 ◽  
Author(s):  
Maria von Balthazar ◽  
Kaj Raunsgaard Pedersen ◽  
Peter R. Crane ◽  
Else Marie Friis
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
Basal Angiosperm ◽  
Eastern North America

scholarly journals Redescription of Arundel formation Ornithomimosaur material and a reinterpretation of Nedcolbertia justinhofmanni as an “Ostrich Dinosaur”: Biogeographic implications

2016 ◽  
Author(s):  
Chase Doran Brownstein
Keyword(s):  
North America ◽  
Northern Hemisphere ◽  
Early Cretaceous ◽  
Fossil Record ◽  
Eastern North America ◽  
Prince George's County ◽  
The Past ◽  
First Time ◽  
Eastern Seaboard

The fossil record of dinosaurs from the Early Cretaceous of eastern North America is scant, especially since few formations from the east are fossiliferous. Among those that are is the Arundel Formation of the eastern seaboard, which has produced among the best dinosaur faunas known from the Early Cretaceous of eastern North America. The diverse dinosaur fauna of this formation has been thoroughly discussed previously, but few of the dinosaur species originally described from the Arundel are still regarded as valid genera. Much of the Arundel material is in need of review and redescription. Among the fossils of dinosaurs from this formation are those referred to ornithomimosaurs. Here, I redescribe ornithomimosaur remains from the Arundel facies of Prince George’s County, Maryland which may be from two distinct ornithomimosaur taxa. These remains provide key information on the theropods of the Early Cretaceous of Eastern North America. Recent discoveries of small theropod material from the Arundel Formation are also reviewed and described for the first time. The description of the Arundel material herein along with recent discoveries of basal ornithomimosaurs in the past 15 years has allowed for comparisons with the coelurosaur Nedcolbertia justinhofmanni, suggesting the latter animal was a basal ornithomimosaurian dinosaur rather than a “generalized” coelurosaur as which it was originally described. Comparisons between the Arundel ornithomimosaur material and similar Asian and European specimens suggest that both extremely basal ornithomimosaurs and more intermediate or derived forms coexisted throughout the northern hemisphere during the Early Cretaceous. Additionally, the possible presence of two distinct ornithomimosaurs in the Arundel allies the Arundel facies with Asian sediments in their coelurosaurian fauna.

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