Disclaimer: Copyright infringement not intended.
- The discovery and study of the exquisitely preserved Kylinxia zhangi fossil from 520 million years ago is a significant scientific achievement that sheds light on the early evolution of arthropods and related organisms.
- Scientists used a CT scanner to examine a rare fossil of Kylinxia zhangi, an ancient relative of arthropods. This fossil was found in the Chengjiang biota of southern China.
- The Chengjiang biota is known for its exceptional preservation of ancient animals. While most arthropod fossils only preserve the hard skeletons, this particular fossil of Kylinxia preserved the entire animal.
- Kylinxia is distantly related to both crustaceans (like crabs and lobsters) and insects. The fossil suggests that Kylinxia and modern arthropods shared a common ancestor with a six-segmented head, similar to that of modern insects.
About Kylinxia zhangi
- It is an extinct arthropod that lived in the early Cambrian period, about 520 million years ago.
- The fossil of the species was uncovered near the town of Chengjiang in the Yunan Province of southern China.
- Kylinxia is among the 250 or so extremely well-preserved fossil animals described from the region, which are together known as Cambrian Chengjiang biota.
- It had a segmented body with a head, thorax, and abdomen.
- Kylinxia sported three eyes on its head, along with a pair of fearsome claws that was possibly used to catch prey.
- It had a fused head shield, a segmented trunk, and jointed legs.
- The creature had a head with six segments, which is similar to modern insects.
- The genus name "Kylinxia" is a combination of arthropod features.
- "Kylin" is derived from the chimeric creature in Chinese mythology, while "xia" a Chinese word that means shrimp-like arthropod.
- The species name "zhangi" is in honor of Yehui Zhang, who contributed additional specimens (paratypes).
- Kylinxia zhangi has been classified as one of the most basal members of Deuteropoda.
- There is a proposed close relationship with the genus Fengzhengia.
Introduction to Arthropods
- Arthropods are a phylum within the animal kingdom, characterized by several distinctive features.
- They are incredibly diverse and make up about 75% of all known animal species on Earth.
- Arthropods can be found in nearly every habitat, ranging from the deep-sea hydrothermal vents to the highest mountain peaks.
Key Characteristics of Arthropods
Arthropods share several key characteristics that define their phylum:
- Exoskeleton: Arthropods have a hard exoskeleton made of chitin, a complex sugar. This exoskeleton serves as both protection and structural support for their bodies. It must be periodically shed and replaced as the arthropod grows.
- Segmented Bodies: Arthropods have segmented bodies, which are divided into distinct regions, including the head, thorax, and abdomen in insects. This segmentation allows for flexibility and specialization of body parts.
- Jointed Appendages: Arthropods have jointed appendages such as legs, antennae, claws, and mouthparts that are attached to their body segments. These appendages are highly adaptable and serve various functions.
- Bilateral Symmetry: They exhibit bilateral symmetry, meaning their bodies are symmetrical on both sides when divided along a central axis.
- Open Circulatory System: Arthropods typically have an open circulatory system in which blood-like fluid called hemolymph circulates in body cavities and directly bathes the internal organs.
Major Groups of Arthropods
Arthropods are divided into four major groups, each with its own unique characteristics:
- Insects: Insects are the largest group of arthropods and include familiar creatures like butterflies, ants, and bees. They have three body segments (head, thorax, and abdomen) and six legs.
- Myriapods: This group includes centipedes and millipedes. Centipedes are fast-moving predators with one pair of legs per body segment, while millipedes are herbivorous and have two pairs of legs per segment.
- Arachnids: Arachnids include spiders, scorpions, ticks, and mites. They have two body segments (cephalothorax and abdomen) and typically eight legs.
- Crustaceans: Crustaceans encompass a wide range of marine and freshwater animals, including crabs, lobsters, shrimp, and barnacles. They often have a hard exoskeleton and appendages adapted for swimming and feeding.
Ecological Roles and Importance
- Arthropods play critical roles in ecosystems.
- They serve as pollinators, decomposers, predators, and prey. In agriculture, they can be pests or beneficial insects that help control pests.
- Arthropods are also essential to nutrient cycling and are a vital part of the food web.
Notable Arthropod Facts
- The largest arthropod is the Japanese spider crab, with leg spans reaching up to 12 feet.
- Some arthropods, like the horseshoe crab, are considered living fossils because they have remained relatively unchanged for millions of years.
- Arthropods have a remarkable diversity of adaptations, from the silk-spinning abilities of spiders to the highly specialized mouthparts of butterflies for sipping nectar.
This discovery contributes to our understanding of the evolutionary history of arthropods and the development of their distinctive features, such as segmented bodies and jointed limbs. It highlights the importance of well-preserved fossils in unraveling the mysteries of ancient life forms.
Q. Which of the following is NOT a major group of arthropods?
Correct Answer: c)