Ontogeny of the trilobite Redlichia from the lower Cambrian (Series 2, Stage 4) Ramsay Limestone of South Australia

Abstract Studies that reveal detailed information about trilobite growth, particularly early developmental stages, are crucial for improving our understanding of the phylogenetic relationships within this iconic group of fossil arthropods. Here we document an essentially complete ontogeny of the trilobite Redlichia cf. versabunda from the Cambrian Series 2 (late Stage 4) Ramsay Limestone of Yorke Peninsula in South Australia, including some of the best-preserved protaspides (the earliest biomineralized trilobite larval stage) known for any Cambrian trilobite. These protaspid stages exhibit similar morphological characteristics to many other taxa within the Suborder Redlichiina, especially to closely related species such as Metaredlichia cylindrica from the early Cambrian period of China. Morphological patterns observed across early developmental stages of different groups within the Order Redlichiida are discussed. Although redlichiine protaspides exhibit similar overall morphologies, certain ontogenetic characters within this suborder have potential phylogenetic signal, with different superfamilies characterized by unique trait combinations in these early growth stages.

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Early post-embryonic development in Ellipsostrenua (Trilobita, Cambrian, Sweden) and the developmental patterns in Ellipsocephaloidea

Journal of Paleontology ◽

10.1017/jpa.2018.25 ◽

2018 ◽

Vol 92 (6) ◽

pp. 1018-1027 ◽

Cited By ~ 3

Author(s):

Lukáš Laibl ◽

Peter Cederström ◽

Per Ahlberg

Keyword(s):

Embryonic Development ◽

Anterior Margin ◽

Developmental Stages ◽

Size Variation ◽

Developmental Patterns ◽

Anterior Branch ◽

Early Developmental Stages ◽

Cambrian Trilobite ◽

Early Developmental ◽

Circular Outline

AbstractThis study documents the early post-embryonic developmental stages (protaspides and early meraspides) of the Cambrian trilobite Ellipsostrenua granulosa (Ahlberg, 1984) from the Gärdsjön Formation of Jämtland, Sweden. The early protaspid stage is characterized by a circular outline of the exoskeleton, two pairs of fixigenal spines, a short preglabellar field, a genal swelling, and prominent bacullae. The late protaspid stage differs only in having the trunk portion discernible. Early meraspid cranidia are sub-rectangular with prominent palpebral lobes, a wide anterior margin, a proportionally long anterior branch of the facial suture, and intergenal spines. Meraspid pygidia tentatively assigned to this species possess comparatively long macrospines. Small hypostomes associated with E. granulosa bear at least four pairs of marginal spines. A comparison of the early developmental stages of E. granulosa with some other species of Ellipsocephalidae and with species of the closely related Estaingiidae reveals several similarities. The conservative morphology of the early protaspid stage with only two pairs of fixigenal spines, the timing of the development of the trunk portion, and the presence of genal swellings and prominent bacullae could be phylogenetically informative. The range of size variation of the early protaspid stages in two families may be related either to taxonomical differences between Ellipsocephalidae and Estaingiidae, or to environmental differences in various paleogeographic settings.

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Review of early developmental stages of trilobites and agnostids from the Barrandian area (Czech Republic)

Journal of the National Museum (Prague), Natural History Series ◽

10.2478/jzh-2018-0006 ◽

2017 ◽

Vol 186 (1) ◽

pp. 103-112

Author(s):

Lukáš Laibl ◽

Oldřich Fatka

Keyword(s):

Czech Republic ◽

Developmental Stages ◽

History Of Research ◽

Early Developmental Stages ◽

History Of ◽

Barrandian Area ◽

Early Developmental

This contribution briefly summarizes the history of research, modes of preservation and stratigraphic distribution of 51 trilobite and five agnostid taxa from the Barrandian area, for which the early developmental stages have been described.

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The Effect of an Anthropogenic Magnetic Field on the Early Developmental Stages of Fishes—A Review

International Journal of Molecular Sciences ◽

10.3390/ijms22031210 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1210

Author(s):

Krzysztof Formicki ◽

Agata Korzelecka-Orkisz ◽

Adam Tański

Keyword(s):

Magnetic Fields ◽

Developmental Stages ◽

Negative Influence ◽

Pigment Cells ◽

Egg Activation ◽

Industrial Equipment ◽

Positive Effects ◽

Early Developmental Stages ◽

Species Specific ◽

Early Developmental

The number of sources of anthropogenic magnetic and electromagnetic fields generated by various underwater facilities, industrial equipment, and transferring devices in aquatic environment is increasing. These have an effect on an array of fish life processes, but especially the early developmental stages. The magnitude of these effects depends on field strength and time of exposure and is species-specific. We review studies on the effect of magnetic fields on the course of embryogenesis, with special reference to survival, the size of the embryos, embryonic motor function, changes in pigment cells, respiration hatching, and directional reactions. We also describe the effect of magnetic fields on sperm motility and egg activation. Magnetic fields can exert positive effects, as in the case of the considerable extension of sperm capability of activation, or have a negative influence in the form of a disturbance in heart rate or developmental instability in inner ear organs.

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Mitochondrial Processes during Early Development of Dictyostelium discoideum: From Bioenergetic to Proteomic Studies

Genes ◽

10.3390/genes12050638 ◽

2021 ◽

Vol 12 (5) ◽

pp. 638

Author(s):

Monika Mazur ◽

Daria Wojciechowska ◽

Ewa Sitkiewicz ◽

Agata Malinowska ◽

Bianka Świderska ◽

...

Keyword(s):

Life Cycle ◽

Developmental Stages ◽

Coupling Efficiency ◽

Slime Mold ◽

Intact Cells ◽

Life Cycle Stages ◽

Early Developmental Stages ◽

Proteomic Study ◽

And Function ◽

Early Developmental

The slime mold Dictyostelium discoideum’s life cycle includes different unicellular and multicellular stages that provide a convenient model for research concerning intracellular and intercellular mechanisms influencing mitochondria’s structure and function. We aim to determine the differences between the mitochondria isolated from the slime mold regarding its early developmental stages induced by starvation, namely the unicellular (U), aggregation (A) and streams (S) stages, at the bioenergetic and proteome levels. We measured the oxygen consumption of intact cells using the Clarke electrode and observed a distinct decrease in mitochondrial coupling capacity for stage S cells and a decrease in mitochondrial coupling efficiency for stage A and S cells. We also found changes in spare respiratory capacity. We performed a wide comparative proteomic study. During the transition from the unicellular stage to the multicellular stage, important proteomic differences occurred in stages A and S relating to the proteins of the main mitochondrial functional groups, showing characteristic tendencies that could be associated with their ongoing adaptation to starvation following cell reprogramming during the switch to gluconeogenesis. We suggest that the main mitochondrial processes are downregulated during the early developmental stages, although this needs to be verified by extending analogous studies to the next slime mold life cycle stages.

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