Video Experimental Relacionado
Updated: Jun 25, 2026
08:02
Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton
Published on: May 7, 2016
Un artrópodo de gran apéndice con una boca radial de la pizarra de Hunsruck del Devónico Inferior, Alemania
Gabriele Kühl1, Derek E G Briggs, Jes Rust
1Division of Palaeontology, Steinmann Institute, University of Bonn, Nussallee 8, 53115 Bonn, Germany.
Science (New York, N.Y.)
|February 7, 2009
Resumen
Un nuevo fósil, Schinderhannes bartelsi, extiende la gama conocida de artrópodos de gran apéndice en 100 millones de años. Este hallazgo revela que las características clave de las anomalocarididas persistieron mucho después de la radiación de euartrópodos.
Área de la Ciencia:
- Paleontología Paleontología.
- Biología evolutiva Biología evolutiva.
- Estudios de Artrópodos Estudios de los Artrópodos Estudios de los Artrópodos
Sus antecedentes:
- Los artrópodos de gran apéndice, definidos por un miembro anterior especializado, solo se conocían anteriormente desde el período Cámbrico Medio.
- La historia evolutiva y la diversidad de los primeros artrópodos siguen siendo áreas de investigación activa.
Objetivo del estudio:
- Describir un nuevo fósil de artrópodos que extiende el rango estratigráfico y temporal conocido de los artrópodos de gran apéndice.
- Investigar la posición filogenética de este nuevo taxón dentro de los primeros euartrópodos.
- Para entender la persistencia de las características anomalocarididas en el registro fósil.
Principales métodos:
- Datación geológica y análisis estratigráfico de la localidad del fósil.
- Examen morfológico detallado del espécimen fósil Schinderhannes bartelsi.
- Análisis filogenético utilizando métodos cladísticos para determinar las relaciones evolutivas.
Principales resultados:
- El descubrimiento de Schinderhannes bartelsi en la pizarra de Hunsrück del Devónico Inferior, Alemania, extiende el rango de los artrópodos de gran apéndice en ~ 100 millones de años.
- Schinderhannes bartelsi exhibe una combinación única de características de anomalocaridida y euartrópodos, incluido un apéndice especializado para nadar.
- El análisis cladístico coloca a este nuevo taxón como basal al grupo de la corona de los euartrópodos, lo que indica que los artrópodos de gran apéndice son parafiléticos.
Conclusiones:
- El descubrimiento de Schinderhannes bartelsi retrasa significativamente el registro fósil conocido de artrópodos de gran apéndice.
- Este fósil demuestra la persistencia a largo plazo de características primitivas, como apéndices raptorios multisegmentados y bocas plateadas, más allá de la radiación inicial de euartrópodos.
Videos de Conceptos Relacionados
01:23Surface Appendages of Archaea
Archaeal surface appendages are highly specialized structures essential for environmental adaptation, encompassing roles in adhesion, biofilm formation, and motility. Among these appendages, pili and archaella stand out for their distinct morphologies and functionalities, enabling archaea to thrive in diverse and often extreme environments.Pili: Adhesion and Biofilm FormationPili are filamentous structures assembled from pilin protein subunits, primarily contributing to adhesion and biofilm...
01:09Overview of the Axial Skeleton
The skeleton is subdivided into two major divisions—the axial skeleton and the appendicular skeleton. The axial skeleton forms the vertical, central axis of the body. It includes all of the bones of the head, neck, chest, and back. It protects the brain, spinal cord, heart, and lungs. It also serves as the attachment site for muscles that move the head, neck, and back and for muscles that act across the shoulder and hip joints to move their corresponding limbs.
The axial skeleton of the adult...
The axial skeleton of the adult...
01:12The Hyoid Bone
The hyoid bone is a small U-shaped bone located in the upper neck at the level of the inferior mandible, with its tips pointing posteriorly. It does not directly articulate with any other bone in the body. The hyoid acts as the attachment site for the tongue, the larynx, and the pharynx. It is held in position by a series of small muscles attached from above or below. These muscles help to move the hyoid up/down or forward/back in coordination with movements of the tongue, larynx, and pharynx...
01:51Lampbrush Chromosomes
In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, Rückert observed LBCs in shark egg cells and coined the term "lampbrush chromosomes" because they looked like brushes used to clean kerosene lamps.
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops resemble the...
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops resemble the...
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,...
01:09Changes in the Appendicular Skeleton with Age
The upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after.
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...