clouded magpie vs Compact Stonewort

Abraxas sylvata compared with Nitella tenuissima

Key Differences

clouded magpie is Vulnerable while Compact Stonewort is Extinct.

Taxonomic Classification

Rank	clouded magpie	Compact Stonewort
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Arthropoda (Arthropods)	Charophyta (Charophyta)
Class	Insecta (Insects)	Charophyceae (Charophyceae)
Order	Lepidoptera (Butterflies & Moths)	Charales (Charales)
Family	Geometridae	Characeae
Genus	Abraxas	Nitella
Species	Abraxas sylvata	Nitella tenuissima

Conservation Status

clouded magpie

VU — Vulnerable

Compact Stonewort

EX — Extinct

Physical Characteristics

Attribute	clouded magpie	Compact Stonewort
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

clouded magpie

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

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

clouded magpie

The clouded magpie (Abraxas sylvata) is a geometrid moth in the family Geometridae found across temperate Europe, extending eastward through Russia to Japan. The adult wingspan measures approximately 32–42 mm, with white wings bearing a distinctive pattern of yellow-orange and dark grey to black spots and patches arranged in rows across the forewing and hindwing, creating a striking patterned appearance resembling the magpie coloring of the related magpie moth Abraxas grossulariata, but with a more yellowish, muted tone and less black — hence 'clouded.' Adults fly in one generation from June to July, resting on leaf surfaces and attending woodland flowers for nectar. The larvae feed on wych elm (Ulmus glabra) and occasionally other Ulmus species in mature deciduous woodland and woodland edges. The clouded magpie has become less common in parts of its European range due to the widespread loss of mature elms from Dutch elm disease, which devastated European elm populations from the 1970s onward. Conservation of this species requires the protection of surviving mature elm trees and management of regrowth elms in woodland ecosystems.

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.