Sprayworms

Sipuncula
Golfingia sp.
Systematics
without rank: Tissue animals (Eumetazoa) without rank: Bilateria without rank: Primordial mouths (protostomia) Over trunk : Lophotrochozoa (Lophotrochozoa) Trunk : Annelids (Annelida) without rank: Sipuncula
Scientific name
Sipuncula
Rafinesque , 1814

The injection worms (Sipuncula) are a group of 320 species of bottom-dwelling sea worms. They are not segmented. The slim trunk-like front body can be pulled into the abdomen. At the end of the front body sits a wreath with antennae with which they ingest their food, detritus and small organisms.

The animals reach lengths between one and 50 centimeters.

Systematics

External system

Until recently, the relationship between the animals was completely unclear. Until well into the 1960s, they were associated, for example, with echinoderms (echinoderms) and also with mollusks (mollusks). Another interpretation established relationships with ringworms (annelids), whereby both a kind of precursor status of the injection worms and a derived status (i.e. secondary loss of body segmentation, based on the ringworm-like initial stage) were postulated.

The latter interpretation has recently been strongly supported by molecular genetic studies. Accordingly, the sipuncula are an inner group of polychaete (Polychaeta) in which anyway numerous cases of secondary segmentation losses are known. This classification implies that the nuchal organs (special chemosensory sensory organs) of the syringe worms are homologous to the nuchal organs of the poly-bristle, which was previously largely rejected by traditional morphology due to structural differences.

With this classification of ringworms, the previous status of the injection worms as a separate animal strain would have to be given up. However, in this respect the annelid worms are currently in the process of dissolving, so that one must first wait for the reorganization of the annelid worms. In general, the injection worms could be described as articulated animals (Articulata) in the broadest sense, but even this once very recognized large group has recently been questioned due to the establishment of the molting animals (Ecdysozoa) as a community of descent.

Internal system

• Class Sipunculidea
  • Order Sipunculiformes
    • Family Sipunculidae
  • Order Golfingiiformes
    • Family Golfingiidae
    • Family Phascolionidae
    • Family Themistidae
• Class Phascolosomatidea
  • Order Phascolosomatiformes
    • Family Phascolosomatidae
  • Order Aspidosiphoniformes
    • Family Aspidosiphonidae

literature

• Hynek Burda , Gero Hilken, Jan Zrzavý: Systematic Zoology. UTB, Stuttgart; : 1st edition 2008, page 121, ISBN 3-8252-3119-4

Individual evidence

1. ↑ C. Bleidorn, L. Podsiadlowski & T. Bartolomaeus (2006): The complete mitochondrial genome of the orbiniid polychaete Orbinia latreillii (Annelida, Orbiniidae) - a novel gene order for Annelida and implications for annelid phylogeny. Gene 370: 96-103

Web links

Commons : Sipuncula  - collection of images, videos and audio files

• Sipuncula Taxa with synonyms (en.)