Nemastoma
C.L. Koch, 1836
harvestman
Species Guides
1- Nemastoma bimaculatum(Gold-spotted Harvestman)
Nemastoma is a of small harvestmen (Opiliones) in the Nemastomatidae, first described by C.L. Koch in 1836. in this genus are litter-dwelling arachnids found primarily in Eurasia, with some introduced in North America. The genus includes with notable morphological diversity, such as the N. bidentatum complex, which exhibits extensive subspecific differentiation and parapatric distribution patterns in Slovenia. Several species have been documented as introduced to North America, including N. bimaculatum, which has established populations in Canada.
Pronunciation
How to pronounce Nemastoma: /nɛˈmæstəmə/
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Identification
Members of Nemastoma can be distinguished from other harvestman by features of the glans, which in some bears two pairs of lateral lancet-like spines, and by the presence of a saw-like series of pointed on IV. The N. bidentatum complex specifically shows variation in these tubercle patterns that aids in distinguishing . Detailed morphological descriptions and illustrations for species identification are available in Martens (1978).
Images
Habitat
Litter-dwelling; occupies forest floor leaf litter and soil . Some occur in spaces within decaying organic matter.
Distribution
Native to Eurasia. Slovenia represents a center of speciation for the N. bidentatum complex, with six of nine present. N. bimaculatum has been introduced to and established in North America, with Canadian records from Ontario.
Behavior
Members of the N. bidentatum complex exhibit parapatric distribution patterns where adjacent form hybrids in contact zones, but distant subspecies do not hybridize. This pattern has been documented in Slovenia where six subspecies form a complex around N. bidentatum schmidti.
Human Relevance
N. bimaculatum and other Nemastoma have been introduced to North America, representing established non-native arachnids in Canada and the United States. These introductions are part of a broader pattern of Eurasian harvestman establishment in North America.
Similar Taxa
- TrogulusBoth are dyspnoid harvestmen in the superfamily Troguloidea, but Nemastoma is distinguished by glans and femoral tuberculation patterns.
- OligolophusAnother introduced Eurasian harvestman in North America; Nemastoma differs in body proportions and genital .
More Details
Species-level diversity
The N. bidentatum complex alone comprises four and six , making it the most diversified harvestman group on a subspecific and young-species level, providing important insights into speciation processes in Opiliones.
Sources and further reading
- BugGuide
- Wikipedia
- iNaturalist taxon
- NCBI Taxonomy
- Catalogue of Life
- Nemastoma_dentigerum_captCollembola__q0-WP - Entomology Today
- Hidden diversity within the Nemastoma bidentatum Roewer, 1914 complex (Opiliones: Nemastomatidae) Part I: Morphological evidence
- The morphology and ecology ofNemastomaandPredaeaspecies (Nemastomataceae, Rhodophyta) from Ghana
- New Canadian records of Nemastoma bimaculatum (Fabricius), and a brief summary of introduced Eurasian harvestmen in North America (Arachnida, Opiliones)
- North Aegean Marine Algae. II. Studies on the Thallus Structure and Reproduction ofNemastoma dichotomumJ. Agardh andPredaea ollivieriJ. Feldmann (Rhodophyta, Gigartinales)