New gametophytes from the Early Devonian Rhynie chert

2003 ◽  
Vol 94 (4) ◽  
pp. 411-428 ◽  
Author(s):  
Hans Kerp ◽  
Nigel H. Trewin ◽  
Hagen Hass
Keyword(s):  
Reproductive Cycle ◽  
Land Plants ◽  
Monotypic Genus ◽  
Early Devonian ◽  
Male And Female ◽  
Rhynie Chert ◽  
Dense Stand

ABSTRACTSeveral new gametophytes are described from the Early Devonian Rhynie chert. The new monotypic genus Remyophyton, being the gametophyte of Rhynia, is represented by a dense stand of in situ preserved gametophytes with antheridia- and archegonia-bearing axes. The gametophytes are remarkably small in comparison to those of other Rhynie chert plants. The generic diagnoses of Lyonophyton and Langiophyton are emended to include archegonia- and antheridiabearing axes. All essential stages of the reproductive cycle, i.e. sporophytes, and male and female gametophytes, can now be demonstrated for three of the six land plants from the Rhynie chert, i.e. Rhynia gwynne-vaughanii, Aglaophyton major and Horneophyton lignieri.

scholarly journals Palaeoecology and palaeophytogeography of the Rhynie chert plants: further evidence from integrated analysis of in situ and dispersed spores

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160491 ◽  
Author(s):  
Charles H. Wellman
Keyword(s):  
Hot Springs ◽  
Terrestrial Ecosystem ◽  
Land Plants ◽  
Integrated Analysis ◽  
Exceptional Preservation ◽  
Rhynie Chert ◽  
Floodplain Deposits ◽  
Early Land

The remarkably preserved Rhynie chert plants remain pivotal to our understanding of early land plants. The extraordinary anatomical detail they preserve is a consequence of exceptional preservation, by silicification, in the hot-springs environment they inhabited. However, this has prompted questions as to just how typical of early land plants the Rhynie chert plants really are. Some have suggested that they were highly adapted to the unusual hot-springs environment and are unrepresentative of ‘normal’ plants of the regional flora. New quantitative analysis of dispersed spore assemblages from the stratigraphical sequence of the Rhynie outlier, coupled with characterization of the in situ spores of the Rhynie chert plants, permits investigation of their palaeoecology and palaeophytogeography. It is shown that the Rhynie inland intermontane basin harboured a relatively diverse flora with only a small proportion of these plants actually inhabiting the hot-springs environment. However, the flora of the Rhynie basin differed from coeval lowland floodplain deposits on the same continent, as it was less diverse, lacked some important spore groups and contained some unique elements. At least some of the Rhynie plants (e.g. Horneophyton lignieri ) existed outside the hot-springs environment, inhabiting the wider basin, and were indeed palaeogeographically widespread. They probably existed in the hot-springs environment because they were preadapted to this unstable and harsh setting. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

Early land plants

1985 ◽  
Vol 309 (1138) ◽  
pp. 197-200 ◽  
Keyword(s):  
New York ◽  
Land Plants ◽  
Early Devonian ◽  
Present Evidence ◽  
Rhynie Chert ◽  
Terrestrial Fungi ◽  
Early Land

After three decades of vigorous research on the Siluro-Devonian floras neither interest nor productivity is slackening. Some newer developments and comments on the two previous papers are listed here to highlight the varied disciplines and approaches that are being brought to bear on Silurian-early Devonian floras. (i) Banks (1981) reported wounds, probably inflicted by chewing microarthropods, in axes of Psilophyton dawsonii repaired by the form ation of a periderm . Unreported evidence indicates wounding and repair stimulated by piercing and sucking activity of other animals. These observations complement the work of Kevan et al. (1975) on arthropods and damage to plants that are found in the Rhynie Chert, and that of Shear et al . (1984) on a new terrestrial fauna from eastern New York. Interest in plant-anim al interrelationships will attract a new group of scholars to the study of Siluro-Devonian plants. Particularly im portant will be the m aceration of large quantities of rock. (ii) Stubblefield & Banks (1983) found oomycetous fungi within cells in the cellularly perm ineralized aerial axes of Psilophyton dawsonii . Rayner (1983) reported apparent fungal bodies in the spines on compression specimens of Sawdonia ornata . These reports supplem ent that by Kevan et al . (1975) on the fungi in the Rhynie Chert. Whether the fungi were parasitic or saprophytic, or were mycorrhizal as suggested by Pirozynski & Malloch (1975), is unclear on the basis of present evidence. Sherwood-Pike & Gray (1985) have isolated hyphae and spores of higher fungi from macerates of mid to late Silurian rocks from Gotland. Other fragments appear to be coprolites of arthropods that include fragments of hyphae. They suggest that fungi and microarthropods may have served as terrestrial decomposers during late Silurian. Pratt et al. (1978) reported septate fungi in earliest Silurian. These introductory works imply a productive future in the study of Siluro-Devonian terrestrial fungi.

scholarly journals Terrestrial invertebrates in the Rhynie chert ecosystem

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160493 ◽  
Author(s):  
Jason A. Dunlop ◽  
Russell J. Garwood
Keyword(s):  
Early Life ◽  
Hot Springs ◽  
Terrestrial Ecosystem ◽  
Early Devonian ◽  
Male And Female ◽  
Terrestrial Invertebrates ◽  
Plant Parasitism ◽  
Liquid Feeding ◽  
Rhynie Chert ◽  
Nematode Worm

The Early Devonian Rhynie and Windyfield cherts remain a key locality for understanding early life and ecology on land. They host the oldest unequivocal nematode worm (Nematoda), which may also offer the earliest evidence for herbivory via plant parasitism. The trigonotarbids (Arachnida: Trigonotarbida) preserve the oldest book lungs and were probably predators that practiced liquid feeding. The oldest mites (Arachnida: Acariformes) are represented by taxa which include mycophages and predators on nematodes today. The earliest harvestman (Arachnida: Opiliones) includes the first preserved tracheae, and male and female genitalia. Myriapods are represented by a scutigeromorph centipede (Chilopoda: Scutigeromorpha), probably a cursorial predator on the substrate, and a putative millipede (Diplopoda). The oldest springtails (Hexapoda: Collembola) were probably mycophages, and another hexapod of uncertain affinities preserves a gut infill of phytodebris. The first true insects (Hexapoda: Insecta) are represented by a species known from chewing (non-carnivorous?) mandibles. Coprolites also provide insights into diet, and we challenge previous assumptions that several taxa were spore-feeders. Rhynie appears to preserve a largely intact community of terrestrial animals, although some expected groups are absent. The known fossils are (ecologically) consistent with at least part of the fauna found around modern Icelandic hot springs. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

scholarly journals Organs and tissues of Rhynie chert plants

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160495 ◽  
Author(s):  
Hans Kerp
Keyword(s):  
Secondary Wall ◽  
Major Part ◽  
Terrestrial Ecosystem ◽  
Regular Pattern ◽  
Intercellular Spaces ◽  
Early Devonian ◽  
Short Stalk ◽  
Rhynie Chert ◽  
Thin Walled

The Early Devonian Rhynie chert and the nearby Windyfield chert contain the oldest in situ preserved terrestrial ecosystem. Two of the seven species of anatomically preserved land plants had naked axes, one an axis with a more or less regular pattern of short-longitudinal ribs, two species had spiny axes and one species had small leaf-like appendages. All plants mainly consist of parenchymatous tissues. In some species, conducting elements comprise uniformly thickened thick-walled cells resembling hydroids of larger bryophytes, whereas others have real tracheids with annular and/or spiral secondary wall thickenings. True phloem has never been demonstrated but in all species the thick-walled water-conducting cells are encircled by a zone of thin-walled cells without intercellular spaces. The cortex is differentiated into two or three zones and forms the major part of the axes; in one species the cells of the middle cortex are sclerified. Some species have a hypodermis. In all species the epidermis is covered by a well-developed cuticle. Sporangia are known from all species. Sporangia are spindle-shaped, lobed or kidney-shaped and attached terminally or laterally with a short stalk. Gametophytes of four species have been described. Gametophytes are unisexual, isomorphic but much smaller than the sporophytes. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

scholarly journals V. On a new type of crustacean from the old red sandstone (Rhymie Chert Bed, Aberdeenshire) — Lepidocaris rhyniensis , gen. et sp. nov

1926 ◽  
Vol 214 (411-420) ◽  
pp. 153-187 ◽  
Keyword(s):  
Land Plants ◽  
British Association ◽  
Subsequent Work ◽  
Red Sandstone ◽  
Animal Remains ◽  
Rhynie Chert ◽  
New Type ◽  
The One

The Chert Bed of Middle, or possibly Lower, Old Red Sandstone age discovered by Dr. W. Mackie (1914) at Rhynie, in Aberdeenshire, has become famous among palæo-botanists on account of the beautifully preserved remains of the earliest known land plants, described by the late Dr. Kidston and Prof. Lang (1917-1921). In addition to the plants, however, the Rhynie Chert also contains animal remains, for the most part very small and in a very fragmentary condition, although the fragments themselves are in many cases exceedingly well preserved. The vast majority of these animal remains are evidently Crustacean in character, and it was at first thought (see British Association Report, 1919, p. 110) that they belonged to several, or at least to two, different species. Subsequent work has, however, convinced me that all the Crustacean remains so far seen in the Rhynie Chert belong to the one species described in this paper.

scholarly journals Affinity binding of non-histone chromatin proteins to the X chromosome of Drosophila by in situ chromatin reconstitution and its significance

1986 ◽  
Vol 86 (1) ◽  
pp. 35-45
Author(s):  
M. Ukil ◽  
K. Chatterjee ◽  
A. Dey ◽  
S. Ghosh ◽  
A.S. Mukherjee
Keyword(s):  
Binding Affinity ◽  
X Chromosome ◽  
Positive Control ◽  
Negative Control ◽  
Chromosomal Protein ◽  
X Chromosomes ◽  
Male And Female ◽  
Interference Band ◽  
Band Filter

Cytophotometric analysis of the in situ binding affinity of non-histone chromosomal protein (NHCP) to the polytenic X chromosome and autosome of Drosophila melanogaster has been carried out using Feulgen-Napthol Yellow S staining technique. The results reveal that the mean transformed absorbance ratio (male:female) with a 547 nm interference band filter for the two specific segments of the X chromosome is close to 0.5, while for a specific segment of an autosome it is close to 1.0, in the two sets of control; namely, the positive control (no treatment) and the negative control (treated with 1 M-urea+2M-NaCl) as well as in the reconstituted chromosomal preparations, which received 1 M-urea+2M-NaCl and the NHCP isolated from D. melanogaster. In contrast, the transformed absorbance ratios (male:female) with a 433 nm interference band filter yielded an interestingly different result. The ratios with a 433 nm filter for the X chromosome segments are significantly greater than 0.5 in all three sets of experiments. This finding by itself suggests that the NHCP binding affinity is dissimilar for the X chromosomes of male and female. When the 433 to 547 nm absorbance ratios were compared among the three sets, the data clearly revealed that in both positive control and NHCP reconstituted samples, the absorbance ratios (i.e. 433:547 nm) are significantly different between X chromosomes from males and those from females, while they are different between autosomes from males and females. The ratios are also not significantly different between male and female, either for the X chromosome or for the autosome in the negative control. These findings, therefore, suggest that there is a stronger binding affinity of NHCP for the male X chromosome of Drosophila, and reinstate the view that the X-chromosomal hyperactivity in male Drosophila is the consequence of a regulated organizational change in the DNA template.

Genetics of reproduction in the rabbit.

2021 ◽  
pp. 212-233
Author(s):  
Miriam Piles ◽  
Maria Antonia Santacreu ◽  
Agustin Blasco ◽  
Jun Pablo Sanchez
Keyword(s):  
Litter Size ◽  
Reproductive Cycle ◽  
Genetic Determinism ◽  
Ovulation Rate ◽  
Biological Processes ◽  
Embryo Survival ◽  
Male And Female ◽  
Fetal Survival

Abstract This chapter describes the genetic determinism of all traits involved in male and female reproductive performances in rabbits. All traits related to the underlying biological processes leading to the mating outcome, as well as some of its general features, such as the homogeneity of the reproductive performances, are considered (semen and ejaculate characteristics, ovulation rate, fertility, embryo survival, fetal survival and litter size). Different parameters of fertility and litter size are discussed, including the contribution of both sexes to each phase of the reproductive cycle.

Hagneia kallea gen. and sp. nov. (Hemiptera: Fulgoromorpha: Ricaniidae) from North Vietnam

Zootaxa ◽  
2020 ◽  
Vol 4861 (2) ◽  
pp. 241-256 ◽  
Author(s):  
ADAM STROIŃSKI
Keyword(s):  
New Species ◽  
Type Species ◽  
Monotypic Genus ◽  
Male And Female ◽  
North Vietnam

A new monotypic genus of ricaniid planthoppers (Hemiptera: Fulgoromorpha: Ricaniidae), Hagneia gen. nov., is described for Hagneia kallea sp. nov. (type species). Habitus, male and female external and internal genital structures of the new species are illustrated. 

scholarly journals Polymorphy and extinction of the Late Cretaceous burrowing shrimp Protocallianassa faujasi and first record of the genera Corallianassa and Calliax (Crustacea, Decapoda, Thalassinoidea) from the Cretaceous

2001 ◽  
Vol 70 (2) ◽  
pp. 85-98 ◽  
Author(s):  
Krista Swen ◽  
René H.B. Fraaije ◽  
Gijsbert J. van der Zwaan
Keyword(s):  
New Species ◽  
First Record ◽  
Suspension Feeding ◽  
Feeding Mode ◽  
Male And Female ◽  
Immature Male ◽  
Type Area ◽  
Mode Of Life ◽  
Burrow Morphology

A biometric study of chelae of the burrowing shrimp Protocallianassa faujasi ( Desmarest, 1822), from the late Maastrichtian of the Maastrichtian type area, The Netherlands, has revealed three morphotypes. These types are interpreted as sexual dimorphs (male and female) and earliest ecdysis stages (immature male). Among the studied material are fifteen specimens of a new Cretaceous callianassid, Corallianassa acucurvata new species, one specimen provisionally assigned to the genus Calliax and a callianassid from the Danian. Burrows preserving callianassid chelae in situ are discussed. Based on burrow morphology a suspension feeding mode of life for P.faujasi is inferred, whereas C. acucurvata n. sp. probably was an active omnivorous analogue of its closest Recent relatives. The extinction of P. faujasi in the Meerssen Member appears to correspond to the increase in seagrass vegetation. The Protocallianassa-Corallianassa faunal changeover took place about 100,000 yrs before the K/T boundary in this region.

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