scholarly journals The early fossil record of glomeromycete fungi: New data on spores associated with early tracheophytes in the Lower Devonian (Emsian; c. 400 Ma) of Gaspé (Quebec, Canada)

2021 ◽  
pp. 104590
Author(s):  
Madison A.K. Lalica ◽  
Alexandru M.F. Tomescu
Keyword(s):  
Fossil Record ◽  
Lower Devonian

scholarly journals Fossil amber reveals springtails’ longstanding dispersal by social insects

2019 ◽  
Author(s):  
Ninon Robin ◽  
Cyrille D'Haese ◽  
Phillip Barden
Keyword(s):  
Fossil Record ◽  
Lower Devonian ◽  
Sister Group ◽  
The Body ◽  
Eusocial Insects ◽  
Significant Challenge ◽  
Dispersal Mechanism ◽  
Close Proximity ◽  
General Constraints ◽  
Drastic Increase

Abstract Background: Dispersal is essential for terrestrial organisms living in disjunct habitats and constitutes a significant challenge for the evolution of wingless taxa. Springtails (Collembola), the sister-group of all insects (with Diplura), are reported since the Lower Devonian and are thought to have originally been subterranean. The order Symphypleona is reported since the early Cretaceous with genera distributed on every continent. This distribution implies an ability to disperse over oceans, however symphypleonan Collembola have never been reported in marine water contrary to other springtail orders. Despite being highly widespread, modern springtails are rarely reported in any kind of biotic association. Interestingly, the fossil record has provided occasional occurrences of Symphypleona attached by the antennae onto the bodies of larger arthropods. Results: Here, we document the case of a ~16 Ma old fossil association: a winged termite and ant displaying not some, but 25 springtails attached or in close proximity to the body. The collembola exhibit rare features for fossils, reflecting their courtship and phoretic behaviours. By observing the modes of attachment of springtails on different arthropods, the sex representation and ratios in springtail antennal anatomies in new and previously reported cases, we infer a likely mechanism for dispersal in Symphypleona. By revealing hidden evidence of modern springtail associations with other invertebrates such as ants and termites, new compelling assemblages of fossil springtails, and the drastic increase of eusocial insects’ abundance during the Cenozoic (ants/termites comprising more than a third of insects in Miocene amber), we stress that attachment on winged castes of ants and termites may have been a mechanism for the worldwide dispersal of this significant springtail lineage. Moreover, by comparing the general constraints applying to the other wingless soil-dwelling arthropods known to disperse through phoresy, we suggest biases in the collection and observation of phoretic Symphypleona related to their reflexive detachment and infer that this behaviour continues today. Conclusions: The specific case of tree resin entrapment represents the (so far) only condition uncovering the phoretic dispersal mechanism of springtails - one of the oldest terrestrial arthropod lineages living today.

A ten-legged sea spider (Arthropoda: Pycnogonida) from the Lower Devonian Hunsrück Slate (Germany)

2013 ◽  
Vol 150 (3) ◽  
pp. 556-564 ◽  
Author(s):  
GABRIELE KÜHL ◽  
MARKUS POSCHMANN ◽  
JES RUST
Keyword(s):  
New Species ◽  
Fossil Record ◽  
Lower Devonian ◽  
Phylogenetic Position ◽  
Crown Group ◽  
Hunsrück Slate ◽  
Sea Spiders ◽  
Sea Spider

AbstractA new sea spider (Arthropoda: Pycnogonida) from the Lower Devonian Hunsrück Slate (Germany) is described asPentapantopus vogteligen. et sp. nov. This is the fifth pycnogonid species known from this exceptional fossil Lagerstätte. The most conspicuous character of the new species is the presence of five pairs of walking legs. This character, in concert with a reduced abdomen, indicates a phylogenetic position ofP. vogteliamong the crown group pycnogonids.P. vogteliextends the knowledge of fossil pycnogonid body plans and underlines the significance of the Hunsrück Slate, as this locality shows the highest diversity of sea spiders for the entire fossil record so far.

The Silurian-Devonian fossil record of the Myriapoda

1985 ◽  
Vol 309 (1138) ◽  
pp. 227-237 ◽  
Keyword(s):  
New York ◽  
Fossil Record ◽  
Discrete Group ◽  
Lower Devonian ◽  
New York State ◽  
Upper Devonian ◽  
York State ◽  
Red Sandstone ◽  
Terrestrial Invertebrates ◽  
Terrestrial Invertebrate

The oldest recorded terrestrial invertebrates are various small Diplopods (millepedes) from the Lower Old Red Sandstone of Britain which were probably preserved preferentially due to their robust calcified exoskeleton. While the myriapod affinities and terrestrial habits of the earliest, pre-Prídolí, claims are highly questionable, true diplopods are known from the latest Silurian (Stonehaven Group) and Lower Devonian of Scotland. In addition, a variety of enigmatic myriapod-like arthropods occur sporadically in the late Silurian-Lower Devonian freshwater facies of the M idland Valley of Scotland and Welsh Borderlands. Among these, the kampecarids ss. constitute a discrete group of short-bodied, diplopodous uniramian arthropods, possibly with myriapod affinities and aquatic habits. In contrast to the diversity of chelicerate groups represented in the later terrestrial invertebrate faunas of Rhynie, Aiken and Gilboa, the Middle to Upper Devonian fossil record of the Myriapoda is very sparse. While true diplopods are notably absent, a variety of fragmentary chilopods (centipedes) are now known from the Gilboa Fauna (Givetian) of New York State.

scholarly journals Stem sarcopterygians have primitive polybasal fin articulation

2009 ◽  
Vol 5 (3) ◽  
pp. 372-375 ◽  
Author(s):  
Min Zhu ◽  
Xiaobo Yu
Keyword(s):  
Fossil Record ◽  
Lower Devonian ◽  
Pectoral Fin ◽  
Temporal Constraint ◽  
Actinopterygian Fishes

Among osteichthyans, basal actinopterygian fishes (e.g. paddlefish and bowfins) have paired fins with three endoskeletal components (pro-, meso- and metapterygia) articulating with polybasal shoulder girdles, while sarcopterygian fishes (lungfish, coelacanths and relatives) have paired fins with one endoskeletal component (metapterygium) articulating with monobasal shoulder girdles. In the fin–limb transition, the origin of the sarcopterygian paired fins triggered new possibilities of fin articulation and movement, and established the proximal segments (stylopod and zeugopod) of the presumptive tetrapod limb. Several authors have stated that the monobasal paired fins in sarcopterygians evolved from a primitive polybasal condition. However, the fossil record has been silent on whether and when the inferred transition took place. Here we describe three-dimensionally preserved shoulder girdles of two stem sarcopterygians ( Psarolepis and Achoania ) from the Lower Devonian of Yunnan, which demonstrate that stem sarcopterygians have polybasal pectoral fin articulation as in basal actinopterygians. This finding provides a phylogenetic and temporal constraint for studying the origin of the stylopod, which must have originated within the stem sarcopterygian lineage through the loss of the propterygium and mesopterygium.

scholarly journals Fossil amber reveals springtails’ longstanding dispersal by social insects

2019 ◽  
Author(s):  
Ninon Robin ◽  
Cyrille D'Haese ◽  
Phillip Barden
Keyword(s):  
Fossil Record ◽  
Lower Devonian ◽  
Sister Group ◽  
The Body ◽  
Eusocial Insects ◽  
Significant Challenge ◽  
Dispersal Mechanism ◽  
Close Proximity ◽  
General Constraints ◽  
Drastic Increase

Abstract Background: Dispersal is essential for terrestrial organisms living in disjunct habitats and constitutes a significant challenge for the evolution of wingless taxa. Springtails (Collembola), the sister-group of all insects (with Diplura), are reported since the Lower Devonian and are thought to have originally been subterranean. The order Symphypleona is reported since the early Cretaceous with genera distributed on every continent. This distribution implies an ability to disperse over oceans, however symphypleonan Collembola have never been reported in marine water contrary to other springtail orders. Despite being highly widespread, modern springtails are rarely reported in any kind of biotic association. Interestingly, the fossil record has provided occasional occurrences of Symphypleona attached by the antennae onto the bodies of larger arthropods. Results: Here, we document the case of a ~16 Ma old fossil association: a winged termite and ant displaying not some, but 25 springtails attached or in close proximity to the body. The collembola exhibit rare features for fossils, reflecting their courtship and phoretic behaviours. By observing the modes of attachment of springtails on different arthropods, the sex representation and ratios in springtail antennal anatomies in new and previously reported cases, we infer a likely mechanism for dispersal in Symphypleona. By revealing hidden evidence of modern springtail associations with other invertebrates such as ants and termites, new compelling assemblages of fossil springtails, and the drastic increase of eusocial insects’ abundance during the Cenozoic (ants/termites comprising more than a third of insects in Miocene amber), we stress that attachment on winged castes of ants and termites may have been a mechanism for the worldwide dispersal of this significant springtail lineage. Moreover, by comparing the general constraints applying to the other wingless soil-dwelling arthropods known to disperse through phoresy, we suggest biases in the collection and observation of phoretic Symphypleona related to their reflexive detachment and infer that this behaviour continues today. Conclusions: The specific case of tree resin entrapment represents the (so far) only condition uncovering the phoretic dispersal mechanism of springtails - one of the oldest terrestrial arthropod lineages living today.

scholarly journals Fossil amber reveals springtails’ longstanding dispersal by social insects

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Ninon Robin ◽  
Cyrille D’Haese ◽  
Phillip Barden
Keyword(s):  
Fossil Record ◽  
Lower Devonian ◽  
Sister Group ◽  
The Body ◽  
Eusocial Insects ◽  
Significant Challenge ◽  
Dispersal Mechanism ◽  
Close Proximity ◽  
General Constraints ◽  
Drastic Increase

Abstract Background Dispersal is essential for terrestrial organisms living in disjunct habitats and constitutes a significant challenge for the evolution of wingless taxa. Springtails (Collembola), the sister-group of all insects (with Diplura), are reported since the Lower Devonian and are thought to have originally been subterranean. The order Symphypleona is reported since the early Cretaceous with genera distributed on every continent. This distribution implies an ability to disperse over oceans, however symphypleonan Collembola have never been reported in marine water contrary to other springtail orders. Despite being highly widespread, modern springtails are rarely reported in any kind of biotic association. Interestingly, the fossil record has provided occasional occurrences of Symphypleona attached by the antennae onto the bodies of larger arthropods. Results Here, we document the case of a ~ 16 Ma old fossil association: a winged termite and ant displaying not some, but 25 springtails attached or in close proximity to the body. The collembola exhibit rare features for fossils, reflecting their courtship and phoretic behaviours. By observing the modes of attachment of springtails on different arthropods, the sex representation and ratios in springtail antennal anatomies in new and previously reported cases, we infer a likely mechanism for dispersal in Symphypleona. By revealing hidden evidence of modern springtail associations with other invertebrates such as ants and termites, new compelling assemblages of fossil springtails, and the drastic increase of eusocial insects’ abundance during the Cenozoic (ants/termites comprising more than a third of insects in Miocene amber), we stress that attachment on winged castes of ants and termites may have been a mechanism for the worldwide dispersal of this significant springtail lineage. Moreover, by comparing the general constraints applying to the other wingless soil-dwelling arthropods known to disperse through phoresy, we suggest biases in the collection and observation of phoretic Symphypleona related to their reflexive detachment and infer that this behaviour continues today. Conclusions The specific case of tree resin entrapment represents the (so far) only condition uncovering the phoretic dispersal mechanism of springtails - one of the oldest terrestrial arthropod lineages living today.

Darwin's two competing phylogenetic trees: marsupials as ancestors or sister taxa?

2012 ◽  
Vol 39 (2) ◽  
pp. 217-233 ◽  
Author(s):  
J. David Archibald
Keyword(s):  
Fossil Record ◽  
Evolutionary Biology ◽  
Phylogenetic Trees ◽  
Charles Darwin ◽  
The Other ◽  
Charles Lyell ◽  
Single Origin ◽  
Molecular Studies ◽  
Richard Owen ◽  
First Time

Studies of the origin and diversification of major groups of plants and animals are contentious topics in current evolutionary biology. This includes the study of the timing and relationships of the two major clades of extant mammals – marsupials and placentals. Molecular studies concerned with marsupial and placental origin and diversification can be at odds with the fossil record. Such studies are, however, not a recent phenomenon. Over 150 years ago Charles Darwin weighed two alternative views on the origin of marsupials and placentals. Less than a year after the publication of On the origin of species, Darwin outlined these in a letter to Charles Lyell dated 23 September 1860. The letter concluded with two competing phylogenetic diagrams. One showed marsupials as ancestral to both living marsupials and placentals, whereas the other showed a non-marsupial, non-placental as being ancestral to both living marsupials and placentals. These two diagrams are published here for the first time. These are the only such competing phylogenetic diagrams that Darwin is known to have produced. In addition to examining the question of mammalian origins in this letter and in other manuscript notes discussed here, Darwin confronted the broader issue as to whether major groups of animals had a single origin (monophyly) or were the result of “continuous creation” as advocated for some groups by Richard Owen. Charles Lyell had held similar views to those of Owen, but it is clear from correspondence with Darwin that he was beginning to accept the idea of monophyly of major groups.

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