coastal arrow worm vs common bottlenose dolphin

Parasagitta setosa compared with Tursiops truncatus

Key Differences

• coastal arrow worm is Not Evaluated while common bottlenose dolphin is Least Concern.

Taxonomic Classification

Rank	coastal arrow worm	common bottlenose dolphin
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Chaetognatha (arrow worms)	Chordata (Chordates)
Class	Sagittoidea (Sagittoidea)	Mammalia (Mammals)
Order	Aphragmophora (Aphragmophora)	Cetacea (Whales & Dolphins)
Family	Sagittidae	Delphinidae (Oceanic Dolphins)
Genus	Parasagitta	Tursiops (Bottlenose Dolphins)
Species	Parasagitta setosa	Tursiops truncatus

Evolutionary Relationship

coastal arrow worm and common bottlenose dolphin share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

coastal arrow worm

NE — Not Evaluated

common bottlenose dolphin

LC — Least Concern

Population: ~600.0K

Trend: Stable →

Physical Characteristics

Attribute	coastal arrow worm	common bottlenose dolphin
Diet	—	Carnivore
Average Lifespan	—	45 years
Average Length	—	3.0 m
Average Weight	—	300.0 kg

Habitat & Geographic Range

coastal arrow worm

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, and Russia.

common bottlenose dolphin

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and tropical and subtropical grasslands and savannas, among 12 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Asia (Taiwan), Europe (6 countries), and South America (Colombia, Ecuador, Venezuela).

coastal arrow worm

Parasagitta setosa, the coastal arrow worm, is a chaetognath in the family Sagittidae inhabiting the coastal and neritic waters of the northeastern Atlantic Ocean and adjacent North Sea and Baltic Sea, with confirmed records from Denmark, Norway, and Russia. Arrow worms are small, transparent, torpedo-shaped marine invertebrates typically 1–5 centimeters long, and despite their common name, are neither worms nor closely related to any familiar animal group; they form their own phylum, Chaetognatha, comprising around 120 species. Parasagitta setosa is a predatory planktonic species, using stiff bristle-like grasping spines flanking its mouth to seize copepods, small fish larvae, and other zooplankton that form the bulk of its diet. It occupies neritic plankton communities, often occurring in brackish coastal waters and estuaries where many arrow worm species cannot tolerate reduced salinity. The species serves as an important prey item for fish including herring and sprat and functions as a significant link in coastal marine food webs. Arrow worm phylogenetic position has been debated extensively; molecular evidence places them near the base of protostome animals. The species is Not Evaluated by the IUCN, as marine zooplankton populations are rarely assessed due to monitoring challenges.

common bottlenose dolphin

The most studied and recognized dolphin species, bottlenose dolphins inhabit warm and temperate oceans worldwide, from coastal shallows to the open sea. Highly intelligent with large brains relative to body size, they demonstrate self-recognition, complex communication, and social learning. They live in fluid fission-fusion societies and cooperate to herd fish. A keystone indicator species for marine ecosystem health.

Shared Countries

Both species can be found in 2 countries:

🇩🇰 Denmark 🇳🇴 Norway