Compact Stonewort vs Lǎohǔ

Nitella tenuissima compared with Panthera tigris

Key Differences

Compact Stonewort is Extinct while Lǎohǔ is Endangered.

Taxonomic Classification

Rank	Compact Stonewort	Lǎohǔ
Kingdom	Plantae (植物)	Animalia (动物界)
Phylum	Charophyta (轮藻门)	Chordata (脊索动物门)
Class	Charophyceae (輪藻綱)	Mammalia (哺乳動物)
Order	Charales (轮藻目)	Carnivora (食肉目)
Family	Characeae	Felidae (Cats)
Genus	Nitella	Panthera (Big Cats)
Species	Nitella tenuissima	Panthera tigris

Conservation Status

Compact Stonewort

EX — Extinct

Lǎohǔ

EN — Endangered

Population: ~4.5K

Trend: Increasing ↑

Physical Characteristics

Attribute	Compact Stonewort	Lǎohǔ
Diet	—	Carnivore
Average Lifespan	—	20 years
Average Length	—	3.0 m
Average Weight	—	220.0 kg

Habitat & Geographic Range

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.

Lǎohǔ

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 6 distinct biome types spanning the Neotropic and Oceanian realms. Populations are also found in montane and highland environments at higher elevations.

Range

Distributed across Colombia and Ecuador. Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

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.