Broadgill Catshark vs Clustered Stonewort

Apristurus riveri compared with Tolypella glomerata

Key Differences

Broadgill Catshark is Least Concern while Clustered Stonewort is Vulnerable.

Taxonomic Classification

Rank	Broadgill Catshark	Clustered Stonewort
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Chordata (Chordates)	Charophyta (Charophyta)
Class	Chondrichthyes (Cartilaginous Fish)	Charophyceae (Charophyceae)
Order	Carcharhiniformes (Ground Sharks)	Charales (Charales)
Family	Scyliorhinidae	Characeae
Genus	Apristurus	Tolypella
Species	Apristurus riveri	Tolypella glomerata

Conservation Status

Broadgill Catshark

LC — Least Concern

Clustered Stonewort

VU — Vulnerable

Physical Characteristics

Attribute	Broadgill Catshark	Clustered Stonewort
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Broadgill Catshark

Habitat

Typically found in marine environments from coastal waters to deep ocean.

Range

Found in Venezuela.

Clustered Stonewort

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, and Sweden. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Broadgill Catshark

The Broadgill Catshark (Apristurus riveri) is a species in the genus Apristurus. It is currently classified as Least Concern on the IUCN Red List. Typically found in marine environments from coastal waters to deep ocean.

Clustered Stonewort

Tolypella glomerata, the clustered stonewort, is a charophyte alga in the family Characeae, found in calcareous, nutrient-poor freshwater habitats including lakes, ponds, ditches, and slow-flowing water in northwestern and northern Europe. Charophytes are macroscopic green algae with a distinctive whorl-like arrangement of branches and a complex, plant-like structure that distinguishes them from other algae. T. glomerata is encrusted with calcium carbonate deposits (hence 'stonewort'), giving it a pale, grey-green appearance and rough texture. The species colonizes clear, low-nutrient water over fine sediment or gravel substrates where competition from vascular plants is reduced by nutrient limitation. It is listed as Vulnerable by the IUCN, reflecting significant declines driven by eutrophication (nutrient enrichment from agriculture and sewage), which promotes the growth of vascular plants and phytoplankton that shade out stoneworts. Drainage, water abstraction, and peat cutting also threaten its habitats. Charophyte diversity has declined substantially across lowland Europe and North America over the past century, with many species becoming locally extinct from sites they once colonized.