Order: Opiliones, Harvestmen

Family: Sclerosomatidae

Leiobunum blackwalli, juveniel

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Family: Sclerosomatidae 9 species in the Netherlands
Astrobunus laevipes (Canestrini, 1872).
Homalenotus quadridentatus (Cuvier, 1795).
Leiobunum blackwalli Meade, 1861.
Leiobunum religiosum Simon, 1879.
Leiobunum rotundum (Latreille, 1798).
Leiobunum spec A. - Reuzenhooiwagen.
Nelima doriae (Canestrini, 1871)
Nelima gothica (Lohmander, 1945).
Nelima sempronii (Szalay, 1951).

Astrobunus laevipes

Astrobunus laevipes is a small animal with short legs, that does not move on disruption, it makes finding very difficult. The females are up to 4.1 mm, males up to 2.9 mm. They are usually under wood on the high tide line of the great rivers. Typical are the light-colored little teeth on top of the eye hillock and the rows of points on the back. The species is rare in Netherlands.

Astrobunus laevipes

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Homalenotus quadridentatus

A flat, small harvestman, with short legs and a skin where the sand is easy stuck on, it is clearly to see on the photos. That is Homalenotus quadridentatus. The animal of the photo is found by Jinze Noordijk. The females and males are up to 4.5 mm. There are two teeth on the front of the animal, a great big with underneath a smaller. On the back there are rows of dark spots and in the end four clearly protruding teeth Above the eye is a number of small teeth.

Homalenotus quadridentatus

I did take the animal home to be able to fotograph it. At home I have placed it in a plastic tray with a piece of tree bark from my garden. Occasionally I enter half a grape or raisin pieces. After three months I see walk two young harvestmen, very very small. I have taken photos of them and again after each molt, so you see below the development of the animals. Number 1 is the first stage.

Homalenotus quadridentatus, juvenile 1

Homalenotus quadridentatus, juvenile 2

Homalenotus quadridentatus, juvenile 3

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Leiobunum blackwalli

At Leiobunum blackwalli females are up to 5.2mm, males up to 3mm. The saddle stain on the back of the female is more or less a triangle that suddenly stops and is followed by a light coloured segment. Male and female you recognize at the eye hillock, this has in both sexes a dark stripe in the middle and light edges around the eyes. Leiobunum rotundum looks much alike, but is easy to distinguish. The eye hillock has in both sexes a light stripe in the middle and dark edges around the eyes and females have an other saddle stain. Later in the season it becomes more difficult to keep the men of both species apart. The eye hillock of both species then turn black. However, males of Leiobunum blackwalli are smaller than of Leiobunum rotundum and have much more black at the front of the body.

Leiobunum blackwalli ♀

Leiobunum blackwalli ♂

Leiobunum blackwalli ♂ later in the season

Leiobunum blackwalli juvenile

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Leiobunum religiosum

On 30-09-2012 Johan Bink finds a female harvestman of a species that was not previously found in the Netherlands. The find is reported in the forum of waarneming.nl and it turns out to be a Leiobunum religiosum. By Jinze Noordijk, the chairman of the harvestman working group, Arp Kruithof, Johan Bink who found the first female, and myself a search tour is organized on 11-10-2012 to find more individuals of this species.
The photos are of the very first animals of this species that are found in the Netherlands. The top two photos are of the female. The bottom two of a male. Characteristic of the species are the light-colored palps, black spots on the bottom and a typical back drawing. The females are up to 7.5mm, males up to 5.5mm. The species also occurs in Germany, France and Italy.

Leiobunum religiosum ♀

Leiobunum religiosum ♂

Leiobunum religiosum ♂
Leiobunum religiosum, ♂, 16-09-2014

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Leiobunum rotundum

This harvestman species forms groups and I have found the species on several places in the nature area Het Metbroekbosch (Smeerling). First a foursome on a hop plant close together, also individuals on nettle and later on three different oak trees in much larger groups. It's a strange sight as you approach such a tree, you see a harvestman running to the rear of the trunk. If you also round the stem you do see a whole group of harvestmen racing from you. This running away you sometimes see also in Platybunus pinetorum but then there is only one specimen that is rushing and jumps from the tree if you're too fast approaching, I have not seen rotundum jump like this.
Leiobunum rotundum has very long legs and has a maximum body length for the female of 5.9mm, for the male 3.6mm. Very striking and a species attribute is the black eye hillock with a lighter stripe in the middle. The men are reddish without drawing, the women have a black rectangle on the back and a black triangle in front of the eyes.

Leiobunum rotundum ♂

Leiobunum rotundum ♀

Leiobunum rotundum couple

Leiobunum rotundum juvenile

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Leiobunum spec.A

This species of harvestman is since about the year 2000 in The Netherlands and it is now clear that it is a new species for science. It is a very large species with very long legs, up to 90 mm and a maximum body length for the female of 6.4 mm, for the male 4.9 mm. The species sometimes forms whole aggregations of harvestmen so there arise a big black spot on a wall of sometimes hundreds of animals.
The animal is much observed by Hay Wijnhoven see (in English): Wijnhoven, H. (2011) Notes on the biology of the unidentified invasive harvestman Leiobunum sp. (Arachnida: Opiliones). Arachnologische Mitteilungen, Vol.41, pp.17-30.

Leiobunum spec A juvenile

Leiobunum spec A ♀

Leiobunum spec A ♀ with ovipositor

Leiobunum spec A ♂

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Nelima doriae

Nelima doriae is known from only one place in The Netherlands. It is first found by Hay Wijnhoven in Kessel, in the province Limburg in 2006. (Wijnhoven, 2007) It is believed that this species is spread by man. Females are up to 6 mm, males up to 3,8 mm. The species is very rare, of origin lies in the Mediterranean. It is difficult to distinguish the species from Nelima sempronii. You should watch for small details if you want to recognize the animal from a picture. There is difference in the eye hillock. There is a black belt at doriae around the eye and in the front of the hillock dark Brown, on top light in colour. The most obvious difference is in the females, which are darker in color than the semproni females.

Nelima doriae, ♂

Nelima doriae, ♀

Nelima doriae, juvenile

Nelima doriae

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Nelima gothica

Nelima gothica lives near the coast or near running water. It is a soil species that lives between the plants or under stones and wood. The females are up to 4.7 mm, males up to 3.5 mm. It is a very rare species. The specimen of the picture is found by Johan Bink.

Nelima gothica

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Nelima sempronii

Nelima sempronii is a pretty simple brown colored harvestman. It is a rare species, these two are photographed in the Ooijpolder at Nijmegen. (Thanks to Hay wijnhoven). In front of the eye hillock is a distinctive light stripe. The tips of the palps are bent inwards. Behind on the body are light stripes and all over the body light dots can be seen.

Nelima sempronii, ♂

Nelima sempronii, ♀

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literature:

Martin, O.Y. & Goodacre, S.L. 2009. Widespread infections by the bacterial endosymbiont Cardinium in arachnids — 2009. The Journal of Arachnology 37:106-108
Noordijk, J. & Bink, J. 2014. Leiobunum religiosum (Opiliones:Sclerosomatidae), een nieuwe hooiwagensoort voor de Nederlandse fauna. — Entomologische Berichten, 74(4). 2014: 21-27.
Wijnhoven, H. 2007 de hooiwagen Nelima doriae nieuw voor nederland (arachnida: opiliones). — Nederlandse Faunistische Mededelingen 26: 69-75.
Wijnhoven, H. (2011) Notes on the biology of the unidentified invasive harvestman Leiobunum sp. (Arachnida: Opiliones). Arachnologische Mitteilungen, Vol.41, pp.17-30.