Concentric Boulder Lichen vs Leatherback Sea Turtle

Porpidia crustulata compared with Dermochelys coriacea

Taxonomic Classification

Rank	Concentric Boulder Lichen	Leatherback Sea Turtle
Kingdom	Fungi (Fungi)	Animalia (Animals)
Phylum	Ascomycota (Sac Fungi)	Chordata (Chordates)
Class	Lecanoromycetes (Lecanoromycetes)	Reptilia (Reptiles)
Order	Lecideales (Lecideales)	Testudines (Turtles & Tortoises)
Family	Lecideaceae	Cheloniidae (Sea Turtles)
Genus	Porpidia	Chelonia (Green Sea Turtles)
Species	Porpidia crustulata	Dermochelys coriacea

Conservation Status

Concentric Boulder Lichen

VU — Vulnerable

Leatherback Sea Turtle

VU — Vulnerable

Population: ~35.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute	Concentric Boulder Lichen	Leatherback Sea Turtle
Diet	—	Carnivore
Average Lifespan	—	50 years
Average Length	—	2.0 m
Average Weight	—	500.0 kg

Habitat & Geographic Range

Concentric Boulder Lichen

Habitat

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

Range

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

Leatherback Sea Turtle

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

Range

Distributed across Costa Rica, Indonesia, Malaysia, and Trinidad and Tobago. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Concentric Boulder Lichen

<em>Porpidia crustulata</em>, commonly known as the Concentric Boulder Lichen, is a crustose lichen in the family Porpidiaceae formed through a symbiotic relationship between a fungal partner (mycobiont) and photosynthetic green algae (photobiont). Like all crustose lichens, it grows tightly appressed to its substrate—typically siliceous or acidic rock surfaces including boulders, cliff faces, and pebbles in open, well-lit habitats—forming thin, grayish to pale thalli marked by scattered black apothecia (reproductive discs). <em>Porpidia crustulata</em> derives nutrition entirely through photosynthesis conducted by its algal partner, requiring no external organic food source. The species has been documented in Denmark, Norway, Portugal, Sweden, and the United States, suggesting a broad boreal to temperate distribution across the Northern Hemisphere. It is currently classified as Vulnerable by the IUCN, indicating significant conservation concern, likely linked to threats including air pollution, acidification, quarrying of rocky habitats, and changes in land use that reduce the availability of suitable substrates. Crustose lichens are typically slow-growing, long-lived organisms with limited capacity for rapid range shifts in response to environmental change. Biological traits such as individual lifespan, growth rates, and reproductive output remain poorly documented at the population level.