Hemichordata
Sign in to saveHemichordata ( ) is a phylum which consists of triploblastic, eucoelomate, and bilaterally symmetrical marine deuterostome animals, generally considered the sister group of the echinoderms. They appear in the Lower or Middle Cambrian and include two main classes: Enteropneusta (acorn worms), and Pterobranchia. A third class, Planctosphaeroidea, is known only from the larva of a single species, Planctosphaera pelagica. The class Graptolithina, formerly considered extinct, is now placed within the pterobranchs, represented by a single living genus Rhabdopleura.
AI overview
Hemichordates are a group of marine animals that share a close evolutionary relationship with starfish and sea urchins, making them important for understanding how different animal groups are related to each other. They include acorn worms and pterobranches, creatures that have existed since the earliest periods of complex animal life and display characteristics that help scientists trace the evolutionary history of larger animal groups.
AI-generated from the Wikipedia summary — may contain errors.
Species
hemichordates
PHYLUM
- KingdomAnimalia
- PhylumHemichordata
Habitatmarine
半索動物門（學名：Hemichordata）是由一類像蟲一般，生存於海底的後口動物所組成的門，通常被認為是棘皮動物的旁系群，可追溯至寒武紀早期或晚期，且包括一類已在泥盆纪時滅絕的重要化石－筆石綱。半索動物似乎有著脊索的原始型態，由前腸的憩室內長出，被稱之為口索，但這更可能只是趨同演化的結果。在一些物種之中，（至少在發育初期）會有一條細長的神經管，這可能是半索動物和脊索動物及其他後口動物的共同祖先所有的原始特徵。
via GBIF
Wikidata facts
- Instance of
- taxon
- Subclass of
- invertebrate
- Parent taxon
- deuterostome
- Image
- Eichelwurm.jpg
Show 4 more facts
Article
12 sectionsContents
- Anatomy
- Neural system
- Circulatory system
- Development
- ''Ptychodera flava''
- ''Saccoglossus kowalevskii''
- Genetic control of dorsal-ventral hemichordate patterning
- Classification
- Phylogeny
- References
- Other references
- External links
Hemichordata ( ) is a phylum which consists of triploblastic, eucoelomate, and bilaterally symmetrical marine deuterostome animals, generally considered the sister group of the echinoderms. They appear in the Lower or Middle Cambrian and include two main classes: Enteropneusta (acorn worms), and Pterobranchia. A third class, Planctosphaeroidea, is known only from the larva of a single species, Planctosphaera pelagica. The class Graptolithina, formerly considered extinct, is now placed within the pterobranchs, represented by a single living genus Rhabdopleura.
Acorn worms are solitary worm-shaped organisms. They generally live in burrows (the earliest secreted tubes) and are deposit feeders, but some species are pharyngeal filter feeders, while the family Torquaratoridae are free-living detritivores. Many are well known for their production and accumulation of various halogenated phenols and pyrroles. Pterobranchs are filter-feeders, mostly colonial, living in a collagenous tubular structure called a coenecium.