Common Elephant Tusk vs Compact Stonewort

Antalis entalis compared with Nitella tenuissima

Key Differences

• Common Elephant Tusk is Least Concern while Compact Stonewort is Extinct.

Taxonomic Classification

Rank	Common Elephant Tusk	Compact Stonewort
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Mollusca (Mollusks)	Charophyta (Charophyta)
Class	Scaphopoda (Scaphopoda)	Charophyceae (Charophyceae)
Order	Dentaliida (Dentaliida)	Charales (Charales)
Family	Dentaliidae	Characeae
Genus	Antalis	Nitella
Species	Antalis entalis	Nitella tenuissima

Conservation Status

Common Elephant Tusk

LC — Least Concern

Compact Stonewort

EX — Extinct

Physical Characteristics

Attribute	Common Elephant Tusk	Compact Stonewort
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Elephant Tusk

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, and Sweden.

Compact Stonewort

Habitat

Native to Asia and Europe and North America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Brazil, Norway, Sweden, Taiwan, and United States.

Common Elephant Tusk

<em>Antalis entalis</em>, the common elephant tusk, is a marine mollusc in the class Scaphopoda, family Dentaliidae, classified as Least Concern by the IUCN Red List. The species is native to European waters and has been documented in Denmark, Norway, and Sweden, inhabiting subtidal and deep benthic zones of the northeastern Atlantic Ocean and North Sea. As a scaphopod, <em>Antalis entalis</em> is characterized by its distinctive curved, tusk-shaped shell that is open at both ends, allowing the animal to partially burrow vertically into sandy or muddy substrates with only the narrow posterior end projecting into the water column. The species feeds on foraminifera and other microscopic organisms in the sediment, capturing prey with specialized tentacle-like structures called captacula that extend through the broader anterior opening of the shell. Scaphopods have limited locomotion and typically remain partially buried throughout their lives. <em>Antalis entalis</em> plays a role in benthic communities as both a consumer of meiofauna and a prey item for predatory fish and invertebrates. Historically, elephant tusk shells of related species were used as currency and ornament by Indigenous peoples of the Pacific Northwest coast. Biological traits of this species remain poorly documented in the scientific literature.

Compact Stonewort

<em>Nitella tenuissima</em>, a stonewort formerly found in fresh and brackish water habitats, was a member of the charophyte family Characeae — the algal lineage most closely related to land plants. Historical records document its occurrence across Brazil, Norway, Sweden, Taiwan, and the United States, where it inhabited clear, oligotrophic lakes, ponds, and slow-flowing water bodies with low nutrient levels. Like other Nitella species, it was a delicate, translucent, submerged aquatic plant lacking the calcium carbonate encrustation of related genera, forming low-growing mats on soft sediments in well-illuminated shallow water. The species played a role in aquatic ecosystems by stabilising lake sediments, contributing to water clarity, and providing microhabitat for invertebrates and small aquatic organisms. <em>Nitella tenuissima</em> is classified as Extinct by the IUCN, having not been recorded from any of its former localities despite targeted searches. The primary causes of its extinction are believed to be widespread eutrophication of freshwater habitats driven by agricultural nutrient runoff and sewage discharge, which eliminated the clear, nutrient-poor conditions on which the species depended. The loss of this stonewort is emblematic of the broader decline of freshwater charophyte diversity across the Northern Hemisphere. Biological traits including historical morphological measurements and reproductive parameters are documented only in sparse historical herbarium specimens and early botanical literature.

Shared Countries

Both species can be found in 2 countries:

🇳🇴 Norway 🇸🇪 Sweden