Thread anchor

Thread anchor
Nemastoma bimaculatum , some legs damaged
Systematics
Sub-stem : Jawbearers (Chelicerata) Class : Arachnids (arachnida) Order : Harvestmen (Opiliones) Subordination : Dyspnoi Superfamily : Troguloidea Family : Thread anchor
Scientific name
Nemastomatidae
Simon , 1872

Thread anchor (Nemastomatidae) are a family of the harvestmen (Opiliones). The division into genera according to genital morphological criteria only succeeded after the work of Roewer (1951), who still assigned most of the species to a genus Nemastoma , which is still the most species-rich in this family.

features

The suture anchors reach a body length of one to six millimeters, depending on the species. Most species are characterized by very long and thin pedipalps . Their chelicerae are of average size. The length of the legs varies within a wide range between species.

Occurrence

The family has a disjoint Holarctic distribution area. It achieved great abundance of forms with the subfamily Nemastomatinae in the west of the Palearctic . Here it is widespread throughout Europe as far as Iceland . Many species live in limited areas in the mountains of southern latitudes, such as the Caucasus , the Atlas in North Africa, from Anatolia to northern Iran and partly in Central Asia to the Himalayas .

In the east of the Palearctic and the Nearctic , the variety of forms is less, the thread anchors living there belong to the subfamily Ortholasmatinae . They live on both coasts of the Pacific , on the one hand on the west coast of North America between Mexico and British Columbia in Canada , on the other hand in East Asia ( Japan and northern Thailand ).

In Europe, this family is represented with 56 species, Central Europe has 17 species, in Germany only nine species from four genera have so far been recorded, including Nemastoma bimaculatum , the Eastern Silberfleckkanker ( Nemastoma lugubre ) and the Einzahnmooskanker ( Nemastoma dentigerum ). Some species are endemic to the Alps , including the Alpine Fadenkanker ( Mitostoma alpinum ) and the black two-thorn ( Paranemastoma bicuspidatum ).

Way of life

The thread anchors feed on insects and mites. They usually live near the ground under wood, leaves or stones. They are often found in mountainous areas where the range of individual species is limited to these mountains.

Systematics

The oldest fossil find of a specimen that can be ascribed to the Fadenkanker family comes from the Cretaceous Period ( Albium ) around 100 million years ago. The species, known from an amber find from Myanmar , was described in 2005 by Gonzalo Giribet and Jason A. Dunlop under the name Halitherses and assigned to the subfamily Ortholasmatinae. An older find from the Permian ( Rotliegend der Goldlauterer layers in Friedrichroda ) from Thuringia was also added to the suture anchor by the first describer in 1957, but is insufficiently described and it was later assumed that the fossil was not a harvestman but a vegetable one Material.

In contrast to many other families of harvestmen, the suture anchors are phylogenetically viewed as monophyletic . The family is divided into two subfamilies, of which the Nemastomatinae comprise most of the genera. A total of 19 genera with over 170 species are currently described:

• Nemastomatinae
  • Acromitostoma
  • Buresiolla
  • Carinostoma
  • Caucnemastoma
  • Centetostoma
  • Giljarovia
  • Hadzinia
  • Historicostoma
  • Mediostoma
  • Mitostomy
  • Nemaspela
  • Nemastoma
  • Nemastomella
  • Paranemastoma
  • Pyza
  • Vestiferum

• Ortholasmatinae
  • Dendrolasma Banks, 1894
  • Martensolasma Shear, 2006
  • Ortholasma Banks, 1894
  • Halitherses Giribet & Dunlop, 2005 (fossil from an amber find from the Cretaceous, age around 100 million years)

• incertae sedis
  • Rhabdotarachnoides (fossil from layers of the Permian, but possibly plant remains )

literature

• Jürgen Gruber: Nemastomatidae Simon, 1872. In: R. Pinto-da-Rocha, G. Machado and G. Giribet (eds.): Harvestmen - The Biology of Opiliones. Harvard University Press, pp. 148 ff., 2007 ISBN 0-674-02343-9

Individual evidence

1. ↑ Joel Hallan: Nemastomatidae Simon . Biology Catalog.
2. ↑ Jochen Martens : Harvesters, Opiliones . The animal world of Germany, 64th part, VEB G. Fischer, Jena 1978
3. ↑ ^{a b} Jürgen Gruber: Nemastomatidae Simon, 1872. In: R. Pinto-da-Rocha, G. Machado and G. Giribet (eds.): Harvestmen - The Biology of Opiliones. Pp. 148 ff., Harvard University Press, 2007
4. ^ ^{A b} Gonzalo Giribet and Jason A. Dunlop: First identifiable Mesozoic harvestman (Opiliones: Dyspnoi) from Cretaceous Burmese amber. Proceedings of The Royal Society B, 272, 1567, pp. 1007-1013, 2005 doi : 10.1098 / rspb.2005.3063 .
5. ↑ ^{a b} Harald Pieper: An alleged harvester (Arachnida, Opiliones) from the Rotliegend of Thuringia. Paläontologische Zeitschrift, 45, 1-2, pp. 79-81, 1971
6. ^ Adriano B. Kury: Checklist of valid genera of Opiliones of the World . Museu Nacional, 2000-2010.

Web links

• Thread anchor at arthropods.de (German)