First report on the expansive harvestmen Dicranopalpus ramosus (Simon, 1909) (Arachnida: Opiliones) in Poland

Abstract

The harvestmen Dicranopalpus ramosus (Simon, 1909) (Arachnida: Opiliones) is reported from Poland for the first time. It was found in the Dąbrówka near Poznań (Wielkopolska Lowland), more than 400 km East of the nearest known localities of this species in Germany.

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FRAGMENTA FAUNISTICA 59 (1): 65–71, 2016
PL ISSN 0015-9301 © MUSEUM AND INSTITUTE OF ZOOLOGY PAS
DOI 10.3161/00159301FF2016.59.1.065
First record of the expansive harvestmen Dicranopalpus ramosus
(Simon, 1909) (Arachnida: Opiliones) in Poland
Robert ROZWAŁKA1 and Tomasz RUTKOWSKI2
1Department of Zoology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland;
e-mail: arachnologia@wp.pl
2Natural History Collections, Faculty of Biology, Adam Mickiewicz University in Poznań, Umultowska 89,
61-614 Poznań, Poland; e-mail: pardosa@gazeta.pl
Abstract: The harvestmen Dicranopalpus ramosus (Simon, 1909) (Arachnida: Opiliones) is reported from Poland for
the first time. It was found in the Dąbrówka near Poznań (Wielkopolska Lowland), more than 400 km East of the
nearest known localities of this species in Germany.
Key words: distribution, expansive species, new site
INTRODUCTION
The genus Dicranopalpus Doleschal, 1852 is represented in Europe by two species: D.
ramosus (Simon, 1909) and D. caudatus Dresco, 1948. For many years D. caudatus was
considered a synonym of D ramosus (Staręga 1973, Martens 1978). Recently Wijnhoven and
Prieto (2015) published the revalidation of taxonomical status of D. caudatus where the authors
presented the accurate description of both species. According to them, D. caudatus is known
from the Iberian Peninsula and two separate localities in southern England, while the range of
D. ramosus extends from Morocco, northern coasts of Spain through France, England and
Ireland, along the coastal zone of continental Europe reaching southern Sweden (Wijnhoven &
Prieto 2015).
The natural area of the Dicranopalpus ramosus, originally covered probably only the
northwestern periphery of the Mediterranean Sea and the southwestern part of the Atlantic
coast, e.g. Morocco, northern Spain and southwestern France (Staręga 1973, Martens 1978,
Hillard & Sankey 1989, Hillard 2005). Findings in Britain, however, supposedly are the result
of the introduction of this species in 1950s from continental Europe (Hillard 2005, Hillard &
Sankey 1989).
In the 90s of the 20th century there was a rapid expansion of the Dicranopalpus ramosus in
Western Europe. Soon, this harvestmen was discovered in the Netherlands (Cuppen 1994),
Ireland (Cawley 1995), Belgium (Slosse 1995), Germany (Schmidt 2004), western and central
France (Delfosse 2004, Delfosse & Iorio 2009). Subsequent publications document the
spreading of D. ramosus in the direction to north of Europe. Toft and Hansen (2011) report
occurrence of this harvestman in Denmark, and Jonsson (2013) in southern Sweden (Fig. 1).
Several publications indicate, that it became a very common species in a short period after its
first record in Western Europe, what was documented in the reports from the Netherlands
(Noordijk et. al. 2007, Wijnhoven 2009), Denmark (Toft & Hansen 2011), Luxemburg (Muster
& Meyer 2014), Germany (Arachnologische Gesellschaft 2016) and Great Britain (Spider and
Harvestman Recording Scheme 2016). Dicranopalpus ramosus is considered as an expansive
species and according the current database of Arachnologische Gesellschaft (2016) the farthest
east positions in Europe were distant by nearly 400 km from the western Polish border.

R. Rozwałka and T. Rutkowski
66
Therefore, the discovery of the population of the species in Dąbrówka near Poznań is now the
easternmost locality of Dicranopalpus ramosus in Europe.
Fig. 1. Distribution of Dicranopalpus ramosus in Europe: asterisk – newly found position, dots – known data from the
nearest location only, shaded area – likely continuous range.
MATERIAL
Location: Dąbrówka near Poznań [UTM XU 10], Lipowa St., geographical coordinates of
the centre of the area: 52°22'58"N, 16°44'44"E.
25 Sep 2014 – 2♂♂, 1♀ (leg. T. Rutkowski); 8 Oct 2014 – 1♂, 1♀ and 1♂ (obs.) (leg. &
obs. T. Rutkowski); 26 Oct 2014 – 2♂♂ (obs. T. Rutkowski); 28 Oct 2014 – 1♂; 29 Oct 2014
– 4 ♂♂ (obs. T. Rutkowski); 4 Nov 2014 – 1♂ (obs. T. Rutkowski); 8 Dec 2014 – 2♂♂ (obs.
T. Rutkowski); 9 Nov 2014 – 1♀ (doc. phot. M. Adamczewski, ver. T. Rutkowski); 26 Nov

Dicranopalpus ramosus in Poland 67
2014 – ♀ (leg. T. Rutkowski); 27 Nov 2014 – 1♂; (leg. T. Rutkowski); 9 Aug 2015 – 4 juv.
(obs. T. Rutkowski); 19 Sep 2015 – 3 juv. (obs. T. Rutkowski); 13 Oct 2015 – 4♂♂, 3♀♀ (obs.
T. Rutkowski); 15 Oct 2015 – 2♂♂ and 3 exx. (obs.) (leg. & obs. T. Rutkowski); 21 Oct 2015
– 2 exx. (obs. T. Rutkowski); 18 Nov 2015 – 2♂♂ (obs. T. Rutkowski); 24 Nov 2015 – 5♂♂
(leg. T. Rutkowski); 25 Nov 2015 – 2♂♂, 3♀♀ (leg. T. Rutkowski); 26 Nov 2015 – 3♂♂ (leg.
T. Rutkowski); 27 Nov 2015 – 1♂, 3♀♀ (leg. T. Rutkowski); 28 Nov 2015 – 2♂♂, 2♀♀ (leg.
T. Rutkowski); 29 Nov 2015 – 4♂♂, 1♀ (leg. T. Rutkowski); 4 Dec 2015 – 1♂ (obs. T.
Rutkowski); 10 Dec 2015 – 1♂ (leg. T. Rutkowski); 14 Dec 2015 – 5♂♂, 1♀ (leg. T.
Rutkowski); 15 Dec 2015 – 2♂♂, 1♀ (obs. T. Rutkowski); 16 Dec 2015 – 2♂♂ (obs. T.
Rutkowski); 17 Dec 2015 – 3♂♂ (leg. T. Rutkowski); 18 Dec 2015 – 4♂♂, 1♀ (leg. T.
Rutkowski); 22 Dec 2015 – 1♂ (leg. T. Rutkowski); 27 Dec 2015 – 1♂ (leg. T. Rutkowski); 28
Dec 2015 – 2♂♂, 1♀ (leg. T. Rutkowski); 30 Dec 2015 – 1♀ (leg. T. Rutkowski); 10 Dec
2015 – 2♂♂, 3♀♀ (leg. T. Rutkowski); 8 Sep 2016 – 1 ex. (obs. T. Rutkowski); 10 Oct 2016 –
1♂, 2♀♀ (obs. T. Rutkowski).
Comparative material: Netherland; province Utrecht, IJsselstein, Sagittapad Str., wall of
building, 28 Aug – 3 Sep 2009 – 1♂; leg. J. Stachowicz, det. et coll. R. Rozwałka.
TAXONOMICAL IDENTIFICATION
Dicranopalpus ramosus is easy to identify. As the only species occurring in Western and
Central Europe, it has long finger-like apophyses on the patella of the pedipalps present in
both sexes (Figs 2g, h & 3). While resting, it takes a specific position, with all its legs spread
sideways, unlike any other species of harvestman found in this part of the continent (Fig. 4).
Male (10 specimens): body ovoid, quite strongly flattened, length from 3.2 to 4.1 mm
(3.7), covered with leathery cuticle (Fig. 2a). The color of the body variables, is a
combination of different shades from yellow-brown to gray-brown in color. Cephalothoracic
part lighter (yellowish-brown, dirty-yellowish, gray-yellowish) with a distinct darker
(brown) lateral, trapezoidal or rectangular strip at the height of the eyes and darker areas of
muscle insertions (Fig. 2a). Ocular tubercle unarmed, yellow-orange, away from the front
edge approximately half of its length. Abdominal part gray-yellowish to gray-brown in color
with a lighter stripe along the midline (Fig. 2a). Chelicerae honey in color, with numerous,
darker tubercles tipped bristles on the dorsal surface of the basal segment and on the frontal
surface of the second segment. Tips of pincers black-brown (Figs 2c, d). The length of the
pedipalps approximately 4.4–5.1 mm (FePe – 1.3) yellow-brown to dark-brown in color (Figs
2g & 3), apical part of the foot distinctly darker. The femur of the pedipalp with short ventral
process. Patella with long finger like apophysis on median side, reaching 2/3 of tibia length
(Figs 2g & 3). The surface of the abdomen uniformly whitish. Coxa, genital operculum and
abdominal sternites with quite a number of dark, short bristles. Coxa white to white-yellow,
trochanters distinctly darker yellow-orange (brown-orange), other segments of the legs
yellow-brown to brown, usually with slightly darker patella and lighter apical parts of femur
and tibia. Tibia of all legs with pseudoarticulations, the number of which varies from 3 to 6
on TiLI, LIII, LIV, and 4–9 on TiLII. Often the number of pseudoarticulations on tibia of left and
right side differs. Length of ♂ legs(Fe+Pa +Ti+Mt+Ta) (in parentheses length of femur): LI – 28.2
(5.3); LII – 51.0 (9.3); LIII – 27.6 (4.9); LIV – 37.0 (6.5). The penis pale-yellow, slightly
sclerotized, around 1.3–1.5 mm in length. Truncus of the penis rod like, in apical part with
tear shaped cavity (Fig. 2i, j), the glans slightly darker, oval, stylus fixed and short, with a
small tuft of bristles on the bottom side (Fig. 2j).

R. Rozwałka and T. Rutkowski
68
Figs 2 (a–m). Dicranopalpus ramosus (Simon): a – male body, dorsal view; b – female body, dorsal view; c – male
chelicerae, lateral view; d – male chelicerae, frontal view; e – female chelicerae, lateral view; f – female chelicerae,
frontal view; g – male pedipalp, dorsal view; h – female pedipalp, dorsal view; i – penis, dorsal view (left) and lateral
view (right); j – glans, lateral view: k – receptaculum seminis; l – ovipositor; m – female body, lateral view. Scale bars:
1.0 mm (a–i, m), 0.2 mm (l), 0.1 mm (j–k).
Female (6 specimens): body elongated, length 4.9–6.0 mm (5.7) with distinct protuberance
at the height of the 4–5 abdominal tergites (Figs 2b, m). Body coloration contrast,
cephalothorax and first two tergites of the abdomen white-grayish other tergites distinctly
darker (dark-gray). Along the midline of the abdomen extends brown framed, fingers like
branched light spot (Fig. 2b). Ocular tubercle unarmed, yellow-orange, away from the front

Dicranopalpus ramosus in Poland 69
edge of the body approximately 2/3 of its length. Muscle insertions darker, as is darker spot
behind ocular tubercle (Fig. 2b). The basic color of chelicera yellowish, with clear brown-black
band on the II segment (Figs 2e, f) and black tips of the pincers. Tubercles on I and II segment
of chelicera present, but in fewer number than in male. The length of the pedipalp 4.9 mm (FePe
– 1.45). The femur of the pedipalp with short ventral process. Patella with long club like
apophysis on median side, reaching almost to the end of the tibia (Fig. 2h). Trochanter and
basal part of the femur whitish to white-yellow, apical part brownish, patella with the process
dark brown, tibia light-brown with lighter apical part, foot gray-brown. Abdominal part of the
body whitish, coxa slightly darker (yellow-whitish), trochanters yellow-orange. The femur and
tibia white-yellowish or light-brown with distinctly darker ring in subapical part and with light
(whitish) apical part. Patella distinctly darker than femur and tibia (brown), other segments of
the legs yellow-brown. Tibia, alike the male with a variable number of pseudoarticulations: 3–
7 on TiLI, LIII, LIV, and 6–12 on TiLII1. Length of ♀ legs (in parentheses length of femur): LI –
24.5 (4.3); LII – 42.2 (7.6); LIII – 23.4 (4.2); LIV – 32.6 (5.6). Ovipositor length approximately
1.7–2.1 mm, width 0.30–0.40 mm, light brown, with 22–27 segments. First 15–17 segments
with a fairly long bristles, gradually declining toward the base. Receptaculum seminis small,
fingers like (Fig. 2k), weakly sclerotized, located mostly in II and III full segment (Fig. 2l).
Fig. 4. Male of Dicranopalpus ramosus on the wall. Photo
by T. Rutkowski
Fig. 3. Male of Dicranopalpus ramosus. Photo by M.
Szewczyk.
1 Wijnhoven (2013), in very detailed analysis performed on bigger number of specimens of D. ramosus also showed high
variability in number of pseudoarticulations on tibia, but he did not mention the differences between right/left side.

R. Rozwałka and T. Rutkowski
70
DISCUSSION
The newly discovered site in Poland is currently the most easterly known position of
Dicranopalpus ramosus in Europe. The nearest noted locality of this harvestman are situated in
central Germany (Lübeck – just about 440 km and Lehrte near Hanover (c.a. 470 km)
(Arachnologische Gesellschaft 2016, Fig. 1). The localization, where D. ramosus were found,
is situated in a rapidly expanding suburban village belonging to the broader suburbs of Poznań.
The harvestmen were collected and observed on a few hundred meter long wall surrounding a
recently built residence, adjacent to the 19th-century park. Observations of many individuals
over a period of several months suggest the existence of a sustainable population rather, than
the effect of accidental introduction of a single individual, or a single deposit of eggs.
However, this site of D. ramosus had to arise relatively recently, since searching for this
species carried out in the immediate area and in several potential locations in western Poland
gave a negative result. Presumably, the source of introduction of D. ramosus can be trees or
ornamental plants brought from Western Europe, used to create a large garden.
In continental Europe Dicranopalpus ramosus is accounted for in mainly synanthropic
environments, where it is found on the walls of buildings and on the trunks of trees, in parks,
gardens, orchards, etc. (Hillard 2005, Noordijk et al. 2007, Wijnhoven 2009, Muster & Mayer
2014). It was also noted from ruderal environments, semi-natural forests, etc. (Muster & Mayer
2014). Data from the UK (Spider and Harvestman Recording Scheme 2016) point to the trunks,
branches and leaves of trees and shrubs in natural environments as the main environment of
occurrence of D. ramosus, and less likely, the data indicate the walls. It is possible that the
advantage of synanthropic posts in continental Europe stems from the fact that these large,
often resting in exposed places harvestmen are just easily noticeable there, in opposition to the
individuals sitting on the trunks of trees, etc. The possibility of such a "methodical error" is
mentioned by Noordijk et al. (2007). The second cause of the differences in the Dicranopalpus
ramosus environmental preferences between Great Britain and continental Europe may be
another phase of expansion. In Great Britain D. ramosus is present since 1950s of the 20th
century, so it is now a long-established species and widely distributed (Spider and Harvestman
Recording Scheme 2016). In the Benelux countries (Wijnhoven 2009, Muster & Meyer 2014),
Germany (Arachnologische Gesellschaft 2016), Denmark (Toft & Hansen 2011), and Sweden
(Jonsson 2013), D. ramosus is a relatively newcomer, therefore, its presence is limited mainly
to anthropogenic environments, from where it is just starting to colonize the natural biotopes.
The colonization scheme confirms the observations of the spread of other invasive harvestman
species in Poland, e.g. Opilio canestrinii (Thorell) (Rozwałka & Staręga 2012) or Odiellus
spinosus (Rozwałka et al. 2013, 2014).
ACKNOWLEDGEMENTS
The authors thank Marian Szewczyk for taking and sharing photos of the Dicranopalpus
ramosus and Maciej Adamczewski for providing photographic documentation.
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STRESZCZENIE
[Pierwsze stwierdzenie ekspansywnego gatunku kosarza Dicranopalpus ramosus (Simon, 1909)
(Arachnida: Opiliones) w Polsce]
Dicranopalpus ramosus jest kosarzem, pochodzącym z południowozachodniej części
Basenu Morza Śródziemnego, który w ostatnich dekadach XX i na początku XXI wieku
rozprzestrzenił się na znacznych obszarach Europy Zachodniej. W pracy autorzy przedstawili
informacje o odkryciu stanowiska D. ramosus Dąbrówce niedaleko Poznania. Stwierdzona
populacja jest oddalona o ponad 400 km od najbliższych znanych stanowisk tego gatunku na
terenie Niemiec i jest najdalej na wschód wysuniętą w obrębie zasięgu tego kosarza. Zebrane
okazy i obserwacje sugerują, że Dicranopalpus ramosus jest na stwierdzonym stanowisku
gatunkiem już zadomowionym. Wprawdzie nie odszukano dalszych stanowisk D. ramosus
w Polsce, ale należy spodziewać się, że proces ekspansji tego gatunku będzie postępował.
Accepted: 28 October 2016