Related Experiment Video
Updated: Jun 5, 2026
10:55
Ablation of a Single Cell From Eight-cell Embryos of the Amphipod Crustacean Parhyale hawaiensis
Published on: March 16, 2014
Ultrastructural analyses support different morphological lineages in the phylum Placozoa Grell, 1971
Loretta Guidi1, Michael Eitel, Erica Cesarini
1Dipartimento di Scienze dell'Uomo, dell'Ambiente e della Natura, Università degli Studi di Urbino Carlo Bo, Campus Scientifico, Località Crocicchia, 61029 Urbino, Italy. loretta.guidi@uniurb.it
Journal of Morphology
|January 20, 2011
Summary
Researchers studied 10 placozoan clones, finding distinct morphological differences that help classify them into five lineages. New cellular structures and fiber cell arrangements were identified, aiding in Placozoa systematics.
Area of Science:
- Marine biology
- Zoology
- Cellular biology
Background:
- Placozoa are simple, enigmatic marine invertebrates.
- Understanding their morphology is key to their evolutionary placement.
- Previous studies lacked detailed cellular and ultrastructural comparisons across lineages.
Purpose of the Study:
- To investigate the morphology and ultrastructure of 10 clonal placozoan lineages.
- To identify and describe new diagnostic morphological characters for Placozoa.
- To provide data crucial for establishing a placozoan systematics.
Main Methods:
- Comparative morphological analysis at cellular and intracellular levels.
- Microscopic examination of 10 clonal placozoan lineages.
- Scoring of various morphological characters.
Main Results:
- Identified significant morphological differences among placozoan clones.
- Recognized five distinct lineages based solely on morphology.
- Described three new diagnostic characters: 'concave disc,' two fiber cell subpopulations, and marginal cells.
- Revealed a complex, three-dimensional fiber cell network.
- Characterized marginal cells as potential stem cells.
Conclusions:
- Morphological data support the recognition of distinct placozoan lineages.
- New ultrastructural details provide a revised understanding of Placozoa basic morphology.
- These findings are foundational for future placozoan systematic studies.
Related Concept Videos
01:27Diversity of Protists III
Rhizaria are a diverse group of unicellular protists characterized by their threadlike cytoplasmic extensions known as pseudopodia. These structures aid in both locomotion and feeding, giving Rhizaria an amoeboid appearance. Their amoeboid morphology once led to taxonomic confusion, but molecular phylogenetics has clarified their evolutionary placement and emphasized their shared use of pseudopodia despite divergent lineages.This clade comprises diverse lineages such as Chlorarachniophyta,...
01:27Diversity of Protists IV
Amoebozoa represent a diverse group of terrestrial and aquatic protists that utilize lobe-shaped pseudopodia for locomotion and feeding. This characteristic differentiates them from the Rhizaria, which possess threadlike pseudopodia. The primary classifications within Amoebozoa include gymnamoebas, entamoebas, and the plasmodial and cellular slime molds. Phylogenetic evidence indicates that Amoebozoa diverged from a lineage that ultimately gave rise to fungi and animals.Gymnamoebas and...
01:26Bacterial Phylum Planctomycetes
Planctomycetes are a group of morphologically distinct bacteria predominantly classified into two orders: Planctomycetales and Brocadiales. These gram-negative bacteria exhibit unique features, including division by budding and the presence of stalks or appendages. Their cells are often found in rosette arrangements, and they are notable for possessing an S-layer in their cell envelope, which is relatively uncommon among bacteria. Additionally, Planctomycetes frequently exhibit intracellular...
01:27Diversity of Protists II
Alveolates are a group of organisms recognized by the presence of alveoli, which are cytoplasmic sacs located beneath the cell membrane. While their function remains uncertain, alveoli may help regulate water balance by controlling how much water enters and leaves the cell. In dinoflagellates, these structures may serve as armor plates. There are three major types of alveolates: ciliates, which move using cilia; dinoflagellates, which use flagella for movement; and apicomplexans, which are...
01:59The Phragmoplast
Cell division is essential for organismal growth and development. In animal cells, the central spindle and its associated proteins form the midbody, a structure that has an essential role in cytokinesis. In plants, the central spindle, along with the microtubules, actin, and other cell components, matures into the phragmoplast, which is necessary for cytokinesis. Unlike the stationary midbody, the phragmoplast expands centrifugally, eventually leading to the formation of the new cell wall.
The...
The...
01:59The Phragmoplast
Cell division is essential for organismal growth and development. In animal cells, the central spindle and its associated proteins form the midbody, a structure that has an essential role in cytokinesis. In plants, the central spindle, along with the microtubules, actin, and other cell components, matures into the phragmoplast, which is necessary for cytokinesis. Unlike the stationary midbody, the phragmoplast expands centrifugally, eventually leading to the formation of the new cell wall.
The...
The...