On the problematic placement of the fossil arthropod Devonopilio hutchinsoni in Opiliones (Arachnida)

Zootaxa ◽  
2021 ◽  
Vol 4915 (2) ◽  
pp. 294-298
Author(s):  
ABEL PÉREZ-GONZÁLEZ ◽  
JEFFREY W. SHULTZ
Keyword(s):  
Terrestrial Ecosystems ◽  
Body Parts ◽  
Compelling Evidence ◽  
Early Devonian ◽  
Terrestrial Arthropods ◽  
Rhynie Chert ◽  
Arthropod Cuticle ◽  
Early Palaeozoic ◽  
Source Of Information ◽  
Single Slide

Harvestmen (Arachnida: Opiliones) were among the earliest terrestrial arthropods but their unmineralized exoskeletons are scarce and often fragmentary as fossils (Palencia et al. 2019). Consequently, the discovery and interpretations of fossil harvestmen from the early Palaeozoic can have disproportionate effects on the understanding of evolution in Opiliones. Recently, Devonopilio hutchinsoni Tihelka, Tian & Cai, 2020, was described as a new fossil harvestman from the well-known Rhynie chert deposits of Scotland, an important source of information on freshwater and terrestrial ecosystems of the early Devonian (Tihelka et al. 2020). This species would be one of the earliest records of harvestmen. The description was based on a single slide showing fragments of arthropod cuticle, which Tihelka et al. interpreted as a harvestmen penis and unspecified associated body parts. As specialists on harvestman morphology and systematics, we were intrigued by these conclusions. However, based on the material presented by Tihelka et al. we find no compelling evidence supporting the proposal that the specimen is a harvestman. 

Evidence for an early terrestrial food web: coprolites from the Early Devonian Rhynie chert

2003 ◽  
Vol 94 (4) ◽  
pp. 371-389 ◽  
Author(s):  
Kate S. Habgood ◽  
Hagen Hass ◽  
Hans Kerp
Keyword(s):  
Distinct Group ◽  
Terrestrial Ecosystems ◽  
Freshwater Ecosystems ◽  
The Other ◽  
List Type ◽  
Early Devonian ◽  
Amorphous Content ◽  
Nutritional Strategy ◽  
Rhynie Chert ◽  
The Continuum

ABSTRACTFossils in the Pragian Rhynie cherts, Aberdeenshire, Scotland, are preserved with exquisite cellular detail, and provide much information on Early Devonian terrestrial and freshwater ecosystems. The fossils include abundant and diverse coprolites which demonstrate the existence of consumers differing in life-habit and diet. The coprolites are small (0.5–3 mm) and diverse in morphology and content, including groups of amorphous coprolites as well as coprolites with identifiable, particulate content. The present authors define three new ichnogenera to accommodate these coprolites: •Lancifaex encompasses elongate coprolites with particulate content, and includes three ichnospecies, distinguished on morphology, L. simplex, L. divisa and L. moniliforma.•Rotundafaex encompasses rotund coprolites with particulate content, and includes a single ichnospecies, R. aggregata.•Bacillafaex encompasses rod-shaped coprolites with amorphous content, and includes two ichnospecies, distinguished on size, B. constipatus and B. mina. Typically, plant spores do not dominate the content of these coprolites, but the population does include some spore-rich coprolites. The presence of spore-rich coprolites in this diverse assemblage adds evidence to the debate on spore-feeding as a nutritional strategy in early terrestrial ecosystems. The authors conclude that the coprolites described here indicate at least four types of consumer including detritivores and herbivores. Spore-rich coprolites might suggest sporivory; however, comparison with the faeces of modern millipedes demonstrates that they might equally well be the product of detritivores. The continuum observed here between spore-rich and spore-poor coprolites implies that, in this assemblage, spore-rich coprolites do not constitute a distinct group. Rather, they are part of a group of elongate, ellipsoidal coprolites with heterogeneous content that includes, at one extreme, coprolites which lack plant spores, and at the other, coprolites which contain abundant plant spores. Most coprolites in this group fall somewhere between the two extr

scholarly journals An introduction to the Rhynie chert

2019 ◽  
Vol 157 (1) ◽  
pp. 47-64 ◽  
Author(s):  
Russell J Garwood ◽  
Heather Oliver ◽  
Alan R T Spencer
Keyword(s):  
Recent Work ◽  
Early Life ◽  
Terrestrial Ecosystems ◽  
Unicellular Eukaryotes ◽  
Geological Setting ◽  
Terrestrial Arthropods ◽  
Evolution Of Life ◽  
Rhynie Chert ◽  
Half Graben ◽  
Geological Magazine

AbstractThe terrestrialization of life has profoundly affected the biosphere, geosphere and atmosphere, and the Geological Magazine has published key works charting the development of our understanding of this process. Integral to this understanding – and featuring in one of the Geological Magazine publications – is the Devonian Rhynie chert Konservat-Lagerstätte located in Aberdeenshire, Scotland. Here we provide a review of the work on this important early terrestrial deposit to date. We begin by highlighting contributions of note in the Geological Magazine improving understanding of terrestrialization and Palaeozoic terrestrial ecosystems. We then introduce the Rhynie chert. The review highlights its geological setting: the Caledonian context of the Rhynie Basin and its nature at the time of deposition of the cherts which host its famous fossils. There follows an introduction to the development of the half-graben in which the cherts and host sediments were deposited, the palaeoenvironment this represented and the taphonomy of the fossils themselves. We subsequently provide an overview of the mineralization and geochemistry of the deposit, and then the fossils found within the Rhynie chert. These include: six plant genera, which continue to provide significant insights into the evolution of life on land; a range of different fungi, with recent work starting to probe plant–fungus interactions; lichens, amoebae and a range of unicellular eukaryotes and prokaryotes (algae and cyanobacteria); and finally a range of both aquatic and terrestrial arthropods. Through continued study coupled with methodological advances, Rhynie fossils will continue to provide unique insights into early life on land.

scholarly journals Identifying appropriate sampling and modelling approaches for analysing distributional patterns of Antarctic terrestrial arthropods along the Victoria Land latitudinal gradient

2010 ◽  
Vol 22 (6) ◽  
pp. 742-748 ◽  
Author(s):  
Tancredi Caruso ◽  
Ian D. Hogg ◽  
Roberto Bargagli
Keyword(s):  
Abiotic Factors ◽  
Relevant Literature ◽  
Biotic Interactions ◽  
Terrestrial Ecosystems ◽  
Climatic Conditions ◽  
Trophic Levels ◽  
Terrestrial Arthropods ◽  
Victoria Land ◽  
Dispersal Capability ◽  
Modelling Techniques

AbstractBiotic communities in Antarctic terrestrial ecosystems are relatively simple and often lack higher trophic levels (e.g. predators); thus, it is often assumed that species’ distributions are mainly affected by abiotic factors such as climatic conditions, which change with increasing latitude, altitude and/or distance from the coast. However, it is becoming increasingly apparent that factors other than geographical gradients affect the distribution of organisms with low dispersal capability such as the terrestrial arthropods. In Victoria Land (East Antarctica) the distribution of springtail (Collembola) and mite (Acari) species vary at scales that range from a few square centimetres to regional and continental. Different species show different scales of variation that relate to factors such as local geological and glaciological history, and biotic interactions, but only weakly with latitudinal/altitudinal gradients. Here, we review the relevant literature and outline more appropriate sampling designs as well as suitable modelling techniques (e.g. linear mixed models and eigenvector mapping), that will more adequately address and identify the range of factors responsible for the distribution of terrestrial arthropods in Antarctica.

The Cuticle of Peripatopsis Moseleyi

1964 ◽  
Vol s3-105 (71) ◽  
pp. 281-299
Author(s):  
ELAINE A. ROBSON
Keyword(s):  
Body Wall ◽  
Light And Electron Microscopy ◽  
Thick Layer ◽  
The Body ◽  
Muscle Fibres ◽  
Terrestrial Arthropods ◽  
Dermal Glands ◽  
Arthropod Cuticle ◽  
Primitive Condition ◽  
Pore Canals

The integument of Peripatopsis moseleyi has been examined by light and electron microscopy with particular reference to the structure and formation of the cuticle. The evidence supports the idea that Peripatus is a true arthropod but not that it has direct affinities with the annelids. The characteristics of arthropod cuticle are present in their simplest form and pore canals and dermal glands are lacking. The cuticle is 1 or 2 µ, thick except in the hardened claws and spines. Above the procuticle (chitinprotein) is a thin 4-layered epicuticle. It is possible that the innermost of the 4 layers (prosclerotin) may correspond to cuticulin of other arthropods. In the claws and spines tanning in this layer extends to the procuticle. Hydrofuge properties of the cuticle probably depend on the outer layers of epicuticle, and it is suggested that the lamina concerned might consist of oriented lipid associated with lipoprotein (Dr. J. W. L. Beament). Wax and cement are absent. Non-wettability of the cuticle is probably ensured by the contours of micropapillae which cover the surface. Similar structures arise in Collembola and other terrestrial arthropods by convergence. The formation of new cuticle before ecdysis is described. After the epicuticular layers are complete, the bulk of the procuticle is laid down in a manner probably common to all arthropods. Secreted materials originate in small vesicles derived from rough endoplasmic reticulum and from scattered Golgi regions. The latter contribute to larger vacuoles which rise to the surface of the cell and liberate material in a fluid state. This later consolidates to form procuticle. Vesicles may also open to the surface directly, and ribosomes probably occur free in the cytoplasm. At this stage the cell surface is reticulate, especially under micropapillae. The ordinary epidermis has only one kind of cell, attached to the cuticle by tonofibrils disposed like the ribs of a shuttlecock, and to the fibrous sheaths of underlying muscle-fibres by special fibres of connective tissue. These features and the presence of numerous sensory papillae are associated with the characteristic mobility of the body wall. The appearance of epidermal pigment granules, mitochondria, the nuclear membrane, and a centriole are noted. No other cells immediately concerned in the formation of cuticle have been found. By contrast myriapods, which do not have wax either, possess dermal glands secreting far more lipid than is found in the Onychophora. The wax layer found in insects and some arachnids constitutes an advance of high selective value which emphasizes the primitive condition of the Onychophora. It is noted that the thick layer of collagen separating the haemocoel from the epidermis probably restricts the transfer of materials. It is suggested that since some features of cuticular structure and formation appear to be common to all arthropods, it is possible that some of the endocrine mechanisms associated with ecdysis may also be similar throughout the phylum.

Earliest ontogeny of Early Palaeozoic Craniiformea: compelling evidence for lecithotrophy

Lethaia ◽  
2012 ◽  
Vol 45 (4) ◽  
pp. 566-573 ◽  
Author(s):  
LEONID E. POPOV ◽  
MICHAEL G. BASSETT ◽  
LARS E. HOLMER
Keyword(s):  
Compelling Evidence ◽  
Early Palaeozoic

The first zosterophyll from the Lower Devonian Rhynie Chert, Aberdeenshire

1991 ◽  
Vol 82 (4) ◽  
pp. 324-332 ◽  
Author(s):  
A. G. Lyon ◽  
Dianne Edwards
Keyword(s):  
Lower Devonian ◽  
New Genus ◽  
New Genus And Species ◽  
Early Devonian ◽  
Precise Positioning ◽  
Cortical Zone ◽  
Lack Of Information ◽  
Rhynie Chert

ABSTRACTFragmentary remains of a vascular sporophyte from the Rhynie Chert are described as a new genus and species, Trichopherophyton teuchansii. The plant, which is characterised by the possession of unicellular spinous hairs, exarch xylem and laterally attached, marginally dehiscent sporangia, is assigned to the Zosterophyllophytina, but lack of information on the arrangement of sporangia prevents its more precise positioning within the subdivision. Unusual features include the combination of circinate tips to axes with almost terete xylem strands, and the lack of a thick-walled outer cortical zone. Associated axes, lacking spinous hairs, but having papillate or rhizoid-like epidermal emergences, are interpreted as likely rhizomes of Trichopherophyton. Features, such as unicellular spinous hairs, rhizoid-like emergences, circinate tipsand parenchymatous cortex are considered in relation to the functioning and growth of aplant inhabiting an early Devonian wetland.

scholarly journals Further evidence for fungivory in the Lower Devonian (Lochkovian) of the Welsh Borderland, UK

PalZ ◽  
2020 ◽  
Vol 94 (4) ◽  
pp. 603-618
Author(s):  
Dianne Edwards ◽  
Lindsey Axe ◽  
Jennifer L. Morris ◽  
Lynne Boddy ◽  
Paul Selden
Keyword(s):  
Carbon Cycling ◽  
Lower Devonian ◽  
Terrestrial Ecosystems ◽  
Lower Surface ◽  
Early Devonian ◽  
Faecal Pellets ◽  
Terrestrial Invertebrates ◽  
Terrestrial Animal ◽  
Complete Digestion ◽  
Terrestrial Fungi

Abstract The recent demonstrations that widespread mid-Palaeozoic Prototaxites and other nematophytes had fungal affinities indicate that terrestrial fungi were important elements in carbon cycling in the Early Devonian. Here, we provide evidence for their participation in the recycling of nutrients by early terrestrial invertebrates. Evidence is in the form of coprolites, both those associated with nematophytes or containing their fragmentary remains. Cylindrical coprolites consistently associated with fungal mats are placed in a new ichnospecies, Bacillafaex myceliorum. Their contents are granular to amorphous, suggestive of complete digestion of the ingested hyphae, with the inference of possession of chitinases in the digestive tracts of the consumers. A further single example comprises a cluster of cylindrical bodies attached to the lower surface of a Nematothallus fragment. Here, homogenisation was less complete, with traces of hyphae remaining. Terrestrial animal fossils have not been found at the locality, but scorpions, pseudoscorpions, Opiliones, mites, centipedes (carnivores) and millipedes, and Collembola (detritivores) have been recorded from the slightly younger Rhynie cherts. Studies of fungivory in extant arthropods have concentrated on Collembola and, to a lesser extent, mites, but their faecal pellets are much smaller than the fossil examples. Millipedes, based on body size and faeces of extant forms, are considered more realistic producers, but little is known about fungal feeding in these animals. Regardless of the affinities of the producers, the diversity in morphology, sizes, aggregations, and composition of nematophyte-containing examples suggests that fungivory was an important component of carbon cycling in early terrestrial ecosystems.

Fungi from the Rhynie chert: a view from the dark side

2003 ◽  
Vol 94 (4) ◽  
pp. 457-473 ◽  
Author(s):  
T. N. Taylor ◽  
S. D. Klavins ◽  
M. Krings ◽  
E. L. Taylor ◽  
H. Kerp ◽  
...  
Keyword(s):  
Fossil Record ◽  
Molecular Data ◽  
Host Responses ◽  
Dark Side ◽  
Early Devonian ◽  
Mycorrhizal Associations ◽  
Rhynie Chert ◽  
Complex Ecosystem ◽  
Taxonomic Groups ◽  
Fungal Interactions

ABSTRACTThe exquisite preservation of organisms in the Early Devonian Rhynie chert ecosystem has permitted the documentation of the morphology and life history biology of fungi belonging to several major taxonomic groups (e.g., Chytridiomycota, Ascomycota, Glomeromycota). The Rhynie chert also provides the first unequivocal evidence in the fossil record of fungal interactions that can in turn be compared with those in modern ecosystems. These interactions in the Rhynie chert involve both green algae and macroplants, with examples of saprophytism, parasitism, and mutualism, including the earliest mycorrhizal associations and lichen symbiosis known to date in the fossil record. Especially significant are several types of specific host responses to fungal infection that indicate that these plants had already evolved methods of defence similar and perhaps analogous to those of extant plants. This suggests that mechanisms underlying the establishment and sustenance of associations of fungi with land plants were well in place prior to the Early Devonian. In addition, a more complete understanding of the microbial organisms involved in this complex ecosystem can also provide calibration points for phylogenies based on molecular data analysis. The richness of the microbial community in the Rhynie chert holds tremendous potential for documenting additional fungal groups, which permits speculation about further interactions with abiotic and biotic components of the environment.

A new crustacean from the Early Devonian Rhynie chert, Aberdeenshire, Scotland

2002 ◽  
Vol 93 (4) ◽  
pp. 355-382 ◽  
Author(s):  
Stephen R. Fayers ◽  
Nigel H. Trewin
Keyword(s):  
Hydrothermal Activity ◽  
The Body ◽  
Early Devonian ◽  
Rhynie Chert

ABSTRACTA new crustacean, Castracollis wilsonae is described from a loose block of the Early Devonian Rhynie chert, found in the vicinity of Rhynie, Aberdeenshire, Scotland. It differs markedly from Lepidocaris rhyniensis, Scourfield 1926, the only other crustacean found in the Rhynie chert.The material comprises complete individuals up to 8 mm long and fragmentary remains. The head is normally damaged and detached from the body, and damage to the anterior of the trunk suggests the specimens are exuviae. The head appears domed with a labrum, robust mandibles, and long biramous antennae. A few specimens exhibit a probable detached cephalo-thoracicshield. The trunk is multi-segmented, comprising similar ring-like somites. The thorax variably comprises up to 26 segments. The anterior 11 segments possess similar long, phyllopodous appendages, the remainder variably possess 10 to 15 phyllopodous appendages with a disposition of one per somite. The abdomen comprises up to 28 apodous segments. The posterior of the body comprises a telson with two furcal rami.The crustacean is most probably a calmanostracan branchiopod. It occurs associated with Lepidocaris, charophytes, cyanobacteria and coprolites within a ‘clotted’ chert texture, indicating subaqueous deposition, most probably in a temporary freshwater pool in an area of surficial hydrothermal activity.

Early terrestrial arthropods: a fragmentary record

1985 ◽  
Vol 309 (1138) ◽  
pp. 207-218 ◽  
Keyword(s):  
Land Plants ◽  
Faecal Pellets ◽  
Delta Plain ◽  
Terrestrial Arthropods ◽  
Mazon Creek ◽  
Continuous Record ◽  
Rhynie Chert ◽  
Animal Interaction ◽  
Lake Deposits ◽  
Early Land

The earliest unequivocal terrestrial fossils are uppermost Silurian (Přídolí) myriapods, presumed to be pioneer decomposers. Descendants of their marine ancestors may be discernible in the Cambrian lobopod Aysheaia (recently challenged). Known euthycarcinoids are too late except as survivors from such a lobopod ancestry. Unique arthropods are also known from Cambrian and Ordovician lake deposits, but shed no light on origin of terrestrial forms. Among relevant arthropods, only scorpions have a continuous record from Silurian aquatic to Devonian terrestrial records (eurypterids are dealt with elsewhere in this volume). Respiratory organs are unknown in Silurian forms, but at least three types of gills may have existed by the Devonian, arguing for great diversification by then, and possible multiple colonization of the land. Trace fossils suggest some Devonian scorpions were amphibious, while development of a pre-oral tube indicates they were adapted for feeding out of water. Morphology of Silurian forms implies they were aquatic, solid feeders. The presence of Silurian fungivorous microarthropods is indicated by Ludlow faecal pellets containing fungal hyphae. The terrestrial decomposer niche was occupied, and soils therefore in existence, by then. Constant humid microclimates created by early land plants were important in enabling land colonization by arthropods otherwise susceptible to desiccation. Mamayev’s gravitational hypothesis provides an explanation for evolution of hexapody from uniramians clambering up and over early land plants. Plants of the Siegenian Rhynie Chert show pathological features that may indicate terrestrial plant-animal interaction by that time, as do other lines of circumstantial evidence. Energy costs incurred by plants producing anti-herbivore and anti-detritivore defences have therefore probably been significant in ecosystems since the Devonian. Recent major backwards extensions in time of terrestrial arthropods prove that the terrestrial geological record is still poorly sampled. Givetian Gilboa shows that, as with early plants, much can be hoped for from study of cuticle fragments. New finds should be sought in pre-Devonian equivalents of the Carboniferous Mazon Creek delta plain facies.

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