Morphogenetic patterns of the shelf‐like protuberance in the late Emsian‐early Eifelian polygnathid conodonts

Lethaia ◽  
2019 ◽  
Vol 53 (3) ◽  
pp. 345-361
Author(s):  
Jian‐Feng Lu ◽  
Peter Königshof
Keyword(s):  
Late Emsian

New Early Devonian pteraspidids (Agnatha, Heterostraci) from Death Valley National Monument, southeastern California

1996 ◽  
Vol 70 (1) ◽  
pp. 152-161 ◽  
Author(s):  
David K. Elliott ◽  
Robert R. Ilyes
Keyword(s):  
Estuarine Environment ◽  
Death Valley ◽  
Early Devonian ◽  
National Monument ◽  
Bearing Unit ◽  
Late Emsian

Two species and genera of pteraspidids (Agnatha, Heterostraci), Blieckaspis priscillae n. gen., and Panamintaspis snowi n. gen. and n. sp., together with two undetermined species, are described from the lower part of the Lippincott Member of the Lost Burro Formation, southeastern California. The sharing of similar faunal elements with the Early Devonian assemblages of the Sevy Dolomite and Water Canyon Formation of Utah and Nevada, respectively, together with stratigraphic constraints on the age of the Death Valley fauna, suggest that these assemblages are age equivalent and have a late Emsian (inversus–serotinus Zones) age. The vertebrate-bearing unit of the Lippincott Member is interpreted as a channel-fill deposit laid down in an estuarine environment with low or fluctuating salinity.

A trilobite faunule from the Lower Devonian of the Saoura Valley, Algeria: biodiversity, morphological variability and palaeobiogeographical affinities

2015 ◽  
Vol 153 (3) ◽  
pp. 357-387 ◽  
Author(s):  
AHMED YACINE KHALDI ◽  
CATHERINE CRÔNIER ◽  
GAUTIER HAINAUT ◽  
ABDELKADER ABBACHE ◽  
ABDELKADER OUALI MEHADJI
Keyword(s):  
Lower Devonian ◽  
Morphological Variability ◽  
North Gondwana ◽  
Late Emsian ◽  
New Occurrences

AbstractTrilobites are widespread in Lower Devonian deposits of north Gondwana, and some have been collected from two known sections of the Saoura Valley in SW Algeria, from the ‘Chefar el Ahmar’ Formation. This formation is considered to be from late Emsian to Frasnian in age, but only the lower parts of this formation have yielded trilobites. Nevertheless, no detailed studies have focused on their biodiversity and their morphological variability. New occurrences of phacopids includingBarrandeops chattertonisp. nov.,Geesops fabreisp. nov.,Austerops legrandisp. nov. andPhacops boudjemaaisp. nov. are described from this area and comparisons are made with closely allied species. These new occurrences have been integrated into analyses of intra- and inter-specific variability and biodiversity.

scholarly journals O DEVONIANO NO ESTADO DO MATO GROSSO DO SUL, BRASIL: NOVA ÁREA DE DISTRIBUIÇÃO E PRESENÇA DE TÍPICA FAUNA MALVINOCÁFRICA

2020 ◽  
Vol 30 (2) ◽  
pp. 38-76
Author(s):  
Sandro Scheffler ◽  
Rafael da Silva ◽  
Daniel Sedorko
Keyword(s):  
The State ◽  
Mato Grosso ◽  
Distribution Maps ◽  
Paraná Basin ◽  
Parana Basin ◽  
Eastern Edge ◽  
Mato Grosso Do Sul ◽  
Late Emsian

Devonian strata are widely known for the eastern edge of the Paraná Basin, particularly in the state of Paraná. However, studies are still scarce on the northwestern border, especially in the state of Mato Grosso do Sul. During the studies, around 120 geological and paleontological sites in the region were identified, and some discrepancies were identified in the distribution maps of the Devonian units (Campos Gerais / Chapada Group) in that state. This paper presents a review on the Devonian strata distribution in Mato Grosso do Sul state, as well a survey of paleontological works in the region of occurrence of the climax Malvinokaffric fauna (Pragian-early Emsian) in order to increase the discussion about the genesis of Devonian deposits. This fauna, combined with other stratigraphic evidences, corroborates a non-compartmentalization of the Paraná Basin for this age. The hypothesis of a tectonism concomitant with the deposition of the Ponta Grossa Formation (=lower Chapada II Group) is raised, mainly to the top of the unit, corroborated by a progradational context followed by a depositional hiatus during the middle Emsian at the end of the Eifelian in the area. It is possible that the Campo Grande Arch only acquired geomorphological expressiveness during the middle Emsian which would be attested by the absence of strata dated as late Emsian / Eifelian in croping areas in the state.

The dipnoan species, Sorbitorhynchus deleaskitus , from the Lower Devonian of Guangxi, China

1993 ◽  
Vol 340 (1291) ◽  
pp. 1-24 ◽  
Keyword(s):  
Lower Devonian ◽  
Early Devonian ◽  
Hyoid Arch ◽  
New Perspective ◽  
Dermal Bones ◽  
Late Emsian

A dipnoan species from the Emsian of Guangxi, China, Sorbitorhynchus deleaskitus , which has previously been diagnosed in the appendix to a more general paper on dipnoan phylogeny (Cambell & Barwick 1990), is described in detail. The head is large and heavily ossified, with cosmine on the external dermal bones. The dental plates are thick and have few poorly defined large tuberosities towards their anterolateral edges. It is the only Early Devonian dipnoan for which the full hyoid arch, gular, basibranchial, and submandibular plates are preserved, and in which the parasphenoid is clearly defined. In many features the genus is more advanced than Dipnorhynchus , but in none is it more advanced than Dipterus , apart from the loss of the buccohypophysial foramen. It gives a new perspective on late Emsian evolution of the group, and reinforces our concept of an independently developing dentine-plated line contemporaneous with a true tooth-plated line.

The ontogeny and systematics of the otarionine trilobite Otarionella from the Devonian of the Montagne Noire, France and the Maider, Morocco

2007 ◽  
Vol 145 (1) ◽  
pp. 55-71 ◽  
Author(s):  
RUDY LEROSEY-AUBRIL ◽  
RAIMUND FEIST ◽  
BRIAN D. E. CHATTERTON
Keyword(s):  
New Species ◽  
Growth Stages ◽  
Juvenile Growth ◽  
Adult Morphology ◽  
Montagne Noire ◽  
First Time ◽  
Late Emsian

AbstractA new otarionine trilobite Otarionella rastrum sp. nov., from the late Emsian Mont Peyroux Formation (Montagne Noire, France), is described. Silicified remains, recovered from the underlying Bissounel Formation (early to late Emsian), are also attributed to this new species. These isolated silicified sclerites represent metaprotaspid to young holaspid growth stages, which enables the almost complete ontogeny of an otarionine trilobite with a spinose adult morphology to be described for the first time. Comparison with associated larval and juvenile growth stages of Cyphaspis reveal that the pattern of juvenile cranidial spine distribution in Otarionella rastrum sp. nov. differs from all patterns described so far in the Otarioninae, in particular that characterizing the tribe Otarionini. A second species, Otarionella lkomalii sp. nov., known only from a complete articulated specimen discovered in the early Eifelian of southern Morocco, is also described. Like the middle Eifelian Otarionella chamaeleo (Basse, 1997), this new species has only ten thoracic segments, with the fourth and the sixth segments each bearing a long axial spine. In the light of the new elements provided by the ontogenetic sequence of O. rastrum sp. nov. and the adult specimens of this species and O. lkomalii sp. nov., the putative synonymy of Otarionella and Otarion is rejected and a restricted concept of the genus Otarionella is defined.

Ontogenetic and intraspecific variation in the late Emsian – Eifelian (Devonian) conodonts Polygnathus serotinus and P. bultyncki in the Prague Basin (Czech Republic) and Nevada (western U.S.)

2013 ◽  
Vol 63 (2) ◽  
pp. 153-174 ◽  
Author(s):  
Gilbert Klapper ◽  
Stanislava Vodrážková
Keyword(s):  
New York ◽  
Czech Republic ◽  
Intraspecific Variation ◽  
Ontogenetic Variation ◽  
Normal Variation ◽  
Important Indicator ◽  
Prague Basin ◽  
Conodont Zonation ◽  
Late Emsian ◽  
Rule Out

Abstract Klapper, G. and Vodražkova, S. 2013. Ontogenetic and intraspecific variation in the late Emsian - Eifelian (Devonian) conodonts Polygnathus serotinus and P. bultyncki in the Prague Basin (Czech Republic) and Nevada (western U.S.). Acta Geologica Polonica, 63 (2), 153-174, Warszawa. Samples from populations of Polygnathus serotinus Telford 1975 and P. bultyncki Weddige 1977 from the Prague Basin and Nevada display normal variation for Devonian conodont species. A considerable number of previous authors, however, have proposed unnecessary synonyms of these two species, primarily because they have not recognized ontogenetic variation. In contrast, we interpret the variation as ontogenetic as well as intraspecific and present detailed synonymies as a result. A third species, P. praetrigonicus Bardashev 1992, which has been carried in open nomenclature for many years, is an important indicator of the basal costatus Zone in the Prague Basin, New York, and Nevada. We review the stratigraphic distribution of these three species and the conodont zonation across the Emsian-Eifelian (Lower-Middle Devonian) boundary. Polygnathus pseudocostatus sp. nov. (partitus-costatus zones, central Nevada) is described herein. We have observed a decrease in the pit size during ontogeny in P. bultyncki although we have not measured enough specimens to rule out intraspecific versus ontogenetic variation.

Sign in / Sign up

Export Citation Format

Share Document