A remarkably well-preserved terrestrial isopod (Peracarida: Isopoda: Armadillidiidae) from the upper Oligocene of Hungary, with remarks on the oniscidean taphonomy

Abstract

Isopods rank among the more successful and diverse peracaridan crustaceans,
the clade of oniscidean isopods (pill-bugs and wood-lice) being one of the few pancrustacean
groups to have successfully invaded terrestrial habitats. Yet, the majority of fossil
occurrences of oniscidean isopods stem from amber deposits and only under very
special circumstances are they preserved in marine settings; such an occurrence is
recorded herein. A single, specifically indeterminate, specimen of Armadillidium from
upper Oligocene strata at Eger (Hungary) is interpreted as a drowned individual that
found itself trapped on a piece of driftwood or was caught by waves while walking on
the seashore. The animal was preserved virtually intact and close to a natural posture.
A near-perfect preservation of the isopod's cuticular surface indicates their potential to
be preserved in marine siliciclastic settings under specific conditions.

Full text

Palaeontologia Electronica
palaeo-electronica.org
Hyžný, Matúš and Dávid, Arpád. 2017. A remarkably well-preserved terrestrial isopod (Peracarida: Isopoda: Armadillidiidae) from the
upper Oligocene of Hungary, with remarks on the oniscidean taphonomy. Palaeontologia Electronica 20.1.5A: 1-11
palaeo-electronica.org/content/2017/1757-oniscidean-isopod-from-hungary
Copyright: March 2017 Palaeontological Association
A remarkably well-preserved terrestrial isopod (Peracarida:
Isopoda: Armadillidiidae) from the upper Oligocene of Hungary,
with remarks on the oniscidean taphonomy
Matúš Hyžný and Arpád Dávid
ABSTRACT
Isopods rank among the more successful and diverse peracaridan crustaceans,
the clade of oniscidean isopods (pill-bugs and wood-lice) being one of the few pancrus-
tacean groups to have successfully invaded terrestrial habitats. Yet, the majority of fos-
sil occurrences of oniscidean isopods stem from amber deposits and only under very
special circumstances are they preserved in marine settings; such an occurrence is
recorded herein. A single, specifically indeterminate, specimen of Armadillidium from
upper Oligocene strata at Eger (Hungary) is interpreted as a drowned individual that
found itself trapped on a piece of driftwood or was caught by waves while walking on
the seashore. The animal was preserved virtually intact and close to a natural posture.
A near-perfect preservation of the isopod's cuticular surface indicates their potential to
be preserved in marine siliciclastic settings under specific conditions.
Matúš Hyžný. Comenius University, Faculty of Natural Sciences, Department of Geology and
Palaeontology, Ilkovičova 6, 842 15 Bratislava, Slovakia; e-mail: hyzny.matus@gmail.com
and Department of Geology and Palaeontology, Natural History Museum, Vienna, Burgring 7, 1010
Vienna, Austria
Arpád Dávid. Debrecen University, Department of Mineralogy and Geology, Egyetemtér 1, 4032 Debrecen,
Hungary
Keywords: Armadillidium; central Europe; cuticle preservation; Egerian; fossil
Submission: 23 November 2015 Acceptance: 23 February 2017
INTRODUCTION
Isopods are among the more successful and
diverse peracaridan crustaceans to inhabit marine,
freshwater and terrestrial habitats alike (Kussakin,
1979; Kensley and Schotte, 1989; Wägele, 1989;
Warburg, 1993; Brusca et al., 2007; Wilson, 2008;
Poore and Bruce, 2012; Sfenthourakis and Taiti,
2015). In fact, together with several representa-
tives of amphipods and brachyuran decapods,
oniscidean isopods are the only pancrustaceans
(except for hexapods) to have adapted to terrestrial
conditions (e.g., Hornung, 2011; Dunlop et al.,
2013). Oniscideans probably originated during the
Carboniferous (Broly et al., 2013), although the

HYŽNÝ & DÁVID: ONISCIDEAN ISOPOD FROM HUNGARY
2
oldest verified occurrence of an oniscidean fossil is
from the Early Cretaceous (Broly et al., 2015).
The fossil record of isopods is insufficiently
known, mainly because of the delicate nature of
their exoskeleton and hence a low fossilisation
potential. A direct consequence of this is that there
are only a few occurrences in which the morphol-
ogy of mouthparts or appendages, which are
important for isopod systematics and taxonomy,
are preserved (e.g., Guinot et al., 2005; Vega et al.,
2005; Feldmann, 2009; Wilson et al., 2011; Nagler
et al., 2016), including specimens preserved in
amber (e.g., Spahr, 1993; Dunlop, 2010; Perkovsky
et al., 2010). In view of the fact that oniscidean iso-
pods live in terrestrial habitats, their fossils are
scarce and are dominated by amber inclusions
(Broly et al., 2013, 2015). Many isopod fossils,
except those preserved in amber, are flattened and
sometimes distorted due to taphonomical pro-
cesses. In this respect, the armadillidiid isopod
specimen from the Oligocene of Hungary reported
herein is remarkable in its three-dimensional pres-
ervation.
Additionally, the specimen described herein
represents the first fossil isopod from Hungary.
From neighbouring countries, Mesozoic isopods
have been recorded from Austria (Bachmayer,
1949, 1955; see also the review of Jurassic iso-
pods by Etter, 2014) and Cenozoic species from
Austria (von Ammon, 1882; Bachmayer, 1947; Tau-
ber, 1950), the Czech Republic (Novák, 1872), Slo-
vakia (Hyžný et al., 2013), Romania (Racovitza
and Sevastos, 1910) and Ukraine (Perkovsky et
al., 2010). However, nearly all these occurrences
involve marine taxa, whereas only the Ukrainian
occurrence is based on oniscideans preserved in
amber (Perkovsky et al., 2010). Thus, the Hungar-
ian specimen of a terrestrial isopod is a worthwhile
addition to the isopod fossil record.
GEOLOGICAL SETTING
The described specimen originates from the
Wind Brickyard, situated in the southeastern part of
Eger, Hungary (GPS co-ordinates: 47°53’47.55” N,
20°23’52.20” E; see Figure 1). This outcrop rep-
resents the stratotype of the Egerian Regional
Stage of the Central Paratethys (Báldi and Seneš,
1975; for a correlation with the Mediterranean
scale, see Piller et al., 2007). The sequence
exposed belongs to nanoplankton zone NP 25 and
the Paragloborotalia opima opima Biozone, corre-
sponding to the Chattian (late Oligocene).
The Wind Brickyard section (Figure 2)
exposes the lower part of the Eger Formation
(Báldi and Seneš, 1975). Several marine facies
(shallow bathyal, sublittoral, littoral and lagoonal)
can be observed here, with diverse flora and fauna
(e.g., Báldi, 1973; Kvaček and Hably, 1991; Dávid,
1993, 1999; Fodor, 2001; and references therein).
Strata assigned to the Eger Formation rest con-
formably on the lower Oligocene Kiscell Clay For-
FIGURE 1. Position of the locality studied within Hungary.

PALAEO-ELECTRONICA.ORG
3
mation (Báldi, 1983). Higher in the section,
glauconitic tuffaceous sandstones are exposed,
and above follows the so-called molluscan clay
(thickness 35–40 m), which contains a rich and
diverse microfauna with foraminifera, small mol-
luscs and teleost otoliths. Higher up, the 5.0–5.5 m
thick sequence of sandy clay (called “middle flora”)
is exposed, followed by approximately 2 m of limo-
nitic sandstones containing a varied, excellently
preserved molluscan fauna. This level is referred to
as the “k” layer (from “kövületes” for fossiliferous, in
Hungarian). The succession continues with brack-
ish, shallow-marine sands, the so-called “m” layer
(from “mytilitic”). Finally, there is a 4–5 m thick level
of limonitic sand on the top of the succession.
The isopod specimen was found in the mol-
luscan clay, which was deposited in a deep sublit-
toral–shallow bathyal environment (Báldi, 1973,
1998). Gastropod, bivalve and dentaliid taxa
belong to the Hinia–Cadulus community. The
upper levels formed in shallow sublittoral (Pitar pol-
ytropa community) and littoral (Tympanotonus-
Pirenella and Mytilus aquitanicus communities)
settings. The occurrence of pieces of driftwood in
the molluscan clay, bioeroded by teredinid bivalves
(Dávid, 2004), illustrates that different trunks could
be transported by currents to great distances from
the coast prior to settlement and final burial.
SYSTEMATIC PALAEONTOLOGY
Order ISOPODA Latreille, 1817
Suborder ONISCIDEA Latreille, 1802
Section CRINOCHETA Legrand, 1946
Family ARMADILLIDIIDAE Brandt, 1833
Remarks. Apparently, the Hungarian specimen
was able to roll up into a ball, thus, it belongs to
conglobating isopods. The general habitus of the
specimen in question may fit to several oniscidean
families, including Armadillidae, Armadillidiidae, or
Eubelidae. One of the autapomorphies of the
Eubelidae is sulcus arcuatus, a longitudinal grove
on the first coxal plate (Taiti et al., 1991; Schmidt,
2003). The studied specimen does not possess
this character, and hence its potential attribution to
Eubelidae is disputed. The uropods of armadillidi-
ids differ from the uropods of other conglobating
Oniscidea: their exopodite is plate-like, truncate
posteriorly. The exopodite fills out the gap between
the pleotelson and the pleon-epimera 5, and their
truncate apical margin is part of the body outline
(Schmidt, 2003). Unfortunately, the Hungarian
specimen does not retain uropods. The pleotelson,
however, is partly preserved and its outline is
undoubtedly triangular, as it is typical for armadilli-
FIGURE 2. Section exposed at the Wind Brickyard in
Eger, Hungary. See text for comments.

HYŽNÝ & DÁVID: ONISCIDEAN ISOPOD FROM HUNGARY
4
diids (Schmidt, 2003), rather than quadrangular,
which is typical for armadiliids (Schmidt, 2003). As
a conclusion, the Hungarian specimen is assigned
to the family Armadillidiidae. Up to now, only a
handful of veritable occurrences of this family are
known from the fossil record (Table 1).
Genus ARMADILLIDIUM Brandt, 1833
Type species. Armadillo vulgaris Latreille, 1804,
by original designation.
Diagnosis. See Sars (1899, p. 188) and Richard-
son (1905, p. 665); see also Schmalfuss (2013, p.
13).
Remarks. Armadillidiids constitute a well-founded
monophyletic group (Schmidt, 2008) that com-
prises about 300 species. The most speciose
genus is Armadillidium Brandt, 1833, with nearly
200 described forms (Schmalfuss, 2003), including
A. vulgare (Latreille, 1804), the “most extensively
investigated species of terrestrial isopods,” as
noted by Schmalfuss (2003, p. 2). According to
Schmalfuss (2013), the genus is defined by: 1)
ability to roll up into a closed ball, which may have
a lemon-like shape; 2) lungs with multiple spiracles
in 1st and 2nd pleopod-exopodite; 3) uropod-exopo-
dite flattened and truncated, filling the space
between epimeron of pleonite 5 and telson; 4) fron-
tal part of head with a triangular shield (which
seems to be a modified supra-antennal line) reach-
ing the level of the upper head surface or surpass-
ing this level; 5) lateral parts of inter-ocular line
present. Unfortunately, the Hungarian specimen
does not possess a head, which precludes a confi-
dent generic assignment. However, we argue that
based on various clues discussed below it is rea-
sonable to assign the specimen to Armadillidium.
The pereonite-epimeron I does not have a
notch (schisma), which is characteristic for many
genera, i.e., Alloschizidium Verhoeff, 1919; Ballo-
dillium Vandel, 1961; Eluma Budde-Lund, 1885;
Paraschizidium Verhoeff, 1918; and Schizidium
Verhoeff, 1901. Thus, the assignment of the Hun-
garian specimen to these genera can be excluded.
Also, based on the smooth cuticular surface, the
assignment to genera with tuberculated represen-
tatives, i.e., Cyphodillidium Verhoeff, 1939; Echi-
narmadillidium Verhoeff, 1901; Paxodillidium
Schmalfuss, 1985; and Platanosphaera Strouhal,
1956, can be excluded. Cristarmadillidium
Arcangeli, 1935; Eleoniscus Racovitza, 1907;
Trichodillidium Schmalfuss, 1989; Troglarmadillid-
ium Verhoeff, 1900; and Typhlarmadillidium Ver-
hoeff, 1900, are known only from a few species,
and their distribution is rather limited. For instance,
representatives of Trichodillidium are so far known
only from Greece, including Crete and adjacent
islands (Schmalfuss, 1989, 2003), whereas mono-
typic Eleoniscus is restricted to southeastern Spain
(Racovitza, 1907; Schmalfuss, 2003). A vast
majority of all species of the family Armadillidiidae
belong to the genus Armadillidium (Schmidt, 2003);
therefore it is the most parsimonious course of
action to interpret the Hungarian specimen as a
representative of this genus. In addition, the
autochtonous European distribution of Armadillid-
ium (Schmalfuss, 2000, 2013) strengthens the
argument in favour of attributing the Hungarian
specimen to that genus.
Armadillidium sp.
Figures 3.1-6, 4.1-3, 5.1
Material. The specimen studied (MM 2015.513.1;
collections of the Matra Museum of Hungarian Nat-
ural History Museum at Gyöngyös, Hungary)
comes from the molluscan clay of the Wind Brick-
yard section at Eger (Figures 1-2). It is preserved
three-dimensionally in poorly lithified sand; no
TAB LE 1. Fossil occurrences of the family Armadillidiidae.
Species Age Country Setting Reference
Armadillidium vulgare Pleistocene France clastics Dalens and Bouthier (1985)
Eoarmadillidium granulatum Pleistocene France clastics Dollfus (1904)
gen. et sp. indet early Miocene Mexico amber Serrano et al. (2007)
Armadillidium pulchellum late Oligocene Germany amber Spahr (1993)
Armadillidium sp. late Oligocene Hungary clastics herein
gen. et sp. indet Eocene Northern Europe amber Weitschat and Wichard (2010)
Disputed by Schmidt (2008)
Armadillidium molassicum middle Miocene Germany clastics Heer (1865)
Armadillidium payangadensis ?Miocene India amber Srivastava et al. (2006)

PALAEO-ELECTRONICA.ORG
5
deformation is observed (Figures 3.1-6, 5.1). All
cuticular surfaces are preserved.
Description. Body oblong-ovate, approximately
twice as long as wide, lateral outlines subparallel,
dorsal surface strongly vaulted and smooth. Ceph-
alon not preserved, but presumed to have been
wider than long (based on the slit in pereonite I).
Pereonites distinctly wider than long, subequal,
each being approximately 1.5 mm in length. No
epimera separated on any pereonite. Epimera of
pereonite I with acute posterior corner, without
schisma. Pleon as wide as pereon. Pleonites 1 and
2 covered at sides by pereonite VII. Terminal seg-
ment of pleon (pleotelson) trapezoidal or triangular
in shape, apparently tapering posteriorly, with bro-
ken posterior margin and probably not extending
beyond epimera of pleonite 5. Uropods broken.
Remarks. The specimen is very well preserved;
however, it lacks head and appendages, which are
crucial for the taxonomy of oniscidean isopods as
discussed by Schmidt (2002). Based on the com-
parisons discussed above it is assigned to the
Armadillidiidae and identified tentatively as a repre-
sentative of Armadillidium. The studied specimen
shows overall similarity to Armadillidium vulgare
(e.g., Sars, 1899, p. 189, pl. 81; Richardson, 1905,
FIGURE 3. Armadillidium sp. from the upper Oligocene of Eger, Hungary (MM 2015.513.1). 1. Lateral (right) view. 2.
Dorsal view. 3. Lateral (left) view. 4. Anterior view; note the missing cephalon. 5. Postero-dorsal view. 6. Posterior
view. Roman numerals indicate pereonites; Arabic numerals refer to pleonites.

HYŽNÝ & DÁVID: ONISCIDEAN ISOPOD FROM HUNGARY
6
p. 666, figure 706; Van Name, 1936, p. 276, figures
157-158; Frankenberger, 1959, plate 2, figure 11;
Hegna, 2010, figures 2A-B) and related species
such as A. pulchellum (Zenker, 1798) (e.g., Sars,
1899, p. 191, plate 83, figure 4). Close comparison,
however, is not possible. Despite the fact that the
chance of discovery of additional specimens is
minimal, we refrain from erecting a new species
based on the present material because of lack of
sufficient number of distinguishing characters.
DISCUSSION
Terrestrial Isopods as Fossils
Because the cuticle of terrestrial isopods con-
tains only minor amounts of materials resistant to
chemical and physical degradation (Neues et al.,
2007), the probability of burial and fossilization in
terrestrial environments is low. In most cases,
extinct oniscideans are preserved as amber inclu-
sions (Spahr, 1993; Schmalfuss, 2003; Dunlop,
2010; Broly et al., 2013, 2015). In view of this,
reports of such animals from other settings are
worth noting. In fact, there are only a few reports
on fossil oniscideans that are not contained in
amber. Based on a single specimen of an oniscid-
ean isopod from the Pleistocene clastic sediments
of France, Dollfus (1904) described a new genus
and species, Eoarmadillidium granulatum. Dallens
and Bouthier (1985) reported A. vulgare from the
Pleistocene of France. Heer (1865) described a
new species, A. molassicum, from the middle Mio-
cene clastic sediments of Germany. Schmidt
(2008), however, disputed the attribution of the
Heer’s specimen to isopods; a millipede would be
a more fitting identification. Contrary to these
instances when only a single specimen was recov-
ered, Eubelum rusingaense Morris, 1979 was
described from numerous specimens from the
lower Miocene lacustrine sediments of Rusinga
Island, Lake Victoria, Kenya. As far as the preser-
vation is concerned, the Hungarian specimen
seems to surpass most of the occurrences dis-
cussed above. Its cuticle is preserved virtually
intact, which is usually not the case in arthropod
fossils, which are tens of millions years old. In fact,
Armadillidium sp. from Eger is the oldest armadilli-
diid isopod reported from siliciclastic sediments
(Table 1). It documents that the cuticular surfaces
of oniscoidean isopods may be very well preserved
under specific conditions in siliciclastic settings;
better preservation is documented only from amber
inclusions.
From the Land to the Sea
The specimen of Armadillidium sp. from the
Wind Brickyard at Eger is preserved in a marine
setting. Similar to many crinochetan isopods,
Armadillidium possesses fairly complex “lungs” in
the pleopod exopodites (e.g., Frankenberger,
1959; Wägele, 1989; Hornung, 2011) and is, there-
fore, adapted to subaerial habitats. The aquatic life
habit of a number of Crinocheta evolved second-
arily (Tabacaru, 1999; Schmidt, 2008), but this is
not the case for Armadillidium, which is a fully ter-
restrial animal. Thus, the marine setting of the
present isopod fossil occurrence was not its natural
habitat. The fossil apparently does not represent a
moult, which typically consists of two parts and is
shed biphasically (Schöbl, 1880; Tait, 1917; Vernet
and Charmantier-Daures, 1994; Charmantier-
Daures and Vernet, 2004; Hornung, 2011). More-
over, freshly moulted individuals of terrestrial iso-
pods often consume their exuvia to regain mineral
content (Steel, 1993; Hornung, 2011, figure 3C). In
short, the Eger fossil is interpreted as a corpse.
Post-mortem transport could have damaged deli-
cate joints between segments of the exoskeleton,
especially over longer distances, which would be
required for a terrestrial isopod to land into a
FIGURE 4. Armadillidium sp. from the upper Oligocene of Eger, Hungary (MM 2015.513.1), interpretative line draw-
ings. 1. Posterior view. 2. Lateral (right) view. 3. Anterior view. Roman numerals indicate pereonites; Arabic numerals
refer to pleonites.

PALAEO-ELECTRONICA.ORG
7
marine depositional setting. It is reasonable to
assume that the animal was introduced into marine
waters when alive and then died almost instantly
as a result of high salinity. Rapid burial must have
occurred to ensure preservation of the delicate
exoskeleton.
The body of the described specimen is slightly
bent and recalls the preservation state of Eubelum
rusingaense . Morris (1979, p. 74, figures 1-11; see
also Figures 5.2-4 here) described and figured sev-
eral specimens of this terrestrial isopod from lacus-
trine deposits in “many degress of enrollment, from
a flat to a relaxed arched condition; six specimens
show a nearly complete enrollment with only a
slight gape between the frontal line and the pleotel-
son.” Apparently, the animals displayed defensive
behaviour, i.e., enrollment, when entering the
water, although without much effect. The Hungar-
ian specimen described herein may illustrate a
similar phenomenon, although it is far from being
completely rolled up. It, however, has a curved
shape and shows an ability to conglobation when
alive.
Yet, how does a fully terrestrial arthropod
become introduced undamaged into a marine set-
ting? Oniscidean isopods usually live under stones
and logs and are often found inside rotting tree
trunks. The molluscan clay at Wind Brickyard con-
tains fossilised driftwood fragments (Dávid, 2004),
which apparently were taken far away from the
coast prior to final settlement and burial. Most
probably the isopod crept out of a crevice and was
washed into the sea, since it was not buried within
the driftwood as would be expected if the log had
sunk with the occupant inside. In fact, soil-dwelling
arthropods are often associated with driftwood
(e.g., Coulson et al., 2002, and references therein)
and rafting has even been suggested to be a dis-
persal agent (Donlan and Nelson, 2003). Neverthe-
less, terrestrial invertebrates occupying crevices in
the wood could easily be washed out into the sea.
Marine conditions, however, were lethal for them
(but see Coulson et al., 2002). The specimen of
Armadillidium recorded herein is considered to be
one of such “unhappy travellers.” Alternatively, the
animal could have been caught by waves while
crawling on the seashore. Since representatives of
the Armadillidiidae occur in a wide range of habi-
tats and some Armadillidium species live close to
the seashore, e.g., A. album or A. fallax (Holthuis,
1945; Vandel, 1962; Warburg, 1993), such sce-
nario would be equally possible.
Distribution of Armadillidium
As far as European distribution is concerned,
armadillidiids are autochtonous to the Mediterra-
nean area (Schmaffuss, 2000, 2013; Schmidt,
2003), which they have occupied at least since the
Paleogene, as documented by the present report
and previously published occurrences (for a review
see Broly et al., 2013; Table 1). Armadillidium has
a radiation centre in the northeastern Mediterra-
FIGURE 5. Fossil oniscidean isopods preserved in natural posture. 1. Armadillidium sp., upper Oligocene of Hungary
(MM 2015.513.1). 2-4. Eubelum rusingaense Morris, 1979, lower Miocene of Kenya, deposited in the collections of the
Natural History Museum, London. 2. BMNH In. 61035. 3. BMNH In. 61036. 4. BMNH In. 61037 (fully enrolled speci-
men).

HYŽNÝ & DÁVID: ONISCIDEAN ISOPOD FROM HUNGARY
8
nean area (Schmalfuss, 2000, 2013). The dating of
the origin of the group is unknown at present, but
the late Oligocene material from Germany (Spahr,
1993) and the roughly coeval Hungarian specimen
reported herein suggest that it is at least 26 million
years old. The genus Armadillidium, however, may
well be paraphyletic (Schmalfuss, 2013); therefore,
any conclusions made at the present state of
knowledge are premature. Today, Armadillidium
exhibits cosmopolitan distribution due to introduc-
ing some species (e.g., A. vulgare) to other areas
(e.g., the New World) by humans (Van Name,
1936; Garthwaite et al., 1995; Jass and Klaus-
meier, 2000).
CONCLUSION
Despite the extreme scarcity of fossil terres-
trial isopods in marine siliciclastic sediments, a
uniquely preserved specimen of Oniscidea is
reported from the upper Oligocene strata of the
Wind Brickyard in Eger (Hungary). Although it does
not preserve a cephalon or appendages, it is
attributed to unidentified species of Armadillidium,
a widespread genus which today occurs in a most
of Europe. Its occurrence in the late Oligocene of
Hungary together with roughly coeval record from
Germany suggests that the genus is at least 26
million years old. The specimen from Wind Brick-
yard is remarkable in the near-perfect preservation
of its cuticular surfaces, suggesting that rather soft
and fragile cuticle of terrestrial isopods may be
very well preserved under specific conditions in
siliciclastic marine settings. Better preservation is
documented only from amber inclusions. The spec-
imen is interpreted as a drowned individual that
found itself either trapped on a piece of driftwood or
caught by waves while on the seashore. It is likely
that rotting logs, now preserved as fossils at the
Wind Brickyard contained some passengers, iso-
pods in particular, before they were washed out to
sea.
ACKNOWLEDGEMENTS
Access to comparative material at the Natural
History Museum, London, was provided by C.J.T.
Mellish. R. Summerfield (NHM, London) is thanked
for assistance in photography of Eubelum rusin-
gaense. J.W.M. Jagt kindly helped with improving
the English of the earlier draft. Three anonymous
reviewers are thanked for their constructive criti-
cism. This research has been supported by the
Slovak Research and Development Agency under
contract no. APVV-0436-12, European Commis-
sion's Research Infrastructure Action via SYNTHE-
SYS Project (GB-TAF 4495) and by Hungarian
Scientific Research Fund (OTKA K112708).
REFERENCES
Arcangeli, A. 1935. Isopodi terrestri di caverne della
Spagna (Collezione del Museo di Storia Naturale di
Madrid). Eos, Revista Española de Entomologia,
10:171-195.
Bachmayer, F. 1947. Zwei neue Asseln aus dem Torton
von Deutsch-Altenburg, Hundsheimer Berg (Nied-
erösterreich). Sitzungsberichte der Österreichischen
Akademie der Wissenschaften, mathematisch-natur-
wissenschaftliche Klasse, Abteilung I, 156:363-369.
Bachmayer, F. 1949. Zwei neue Asseln aus dem Ober-
jurakalk von Ernstbrunn, Niederösterreich. Sitzungs-
berichte der Österreichischen Akademie der
Wissenschaften, mathematisch-naturwissenschaftli-
che Klasse, Abteilung I, 158:263-270.
Bachmayer, F. 1955. Die fossilen Asseln aus den Ober-
juraschichten von Ernstbrunn in Niederösterreich und
von Stramberg in Mähren. Sitzungsberichte der
Österreichischen Akademie der Wissenschaften,
mathematisch-naturwissenschaftliche Klasse, Abtei-
lung I, 164:255-273
Báldi, T. 1973. Mollusc fauna of the Hungarian Upper
Oligocene (Egerian). Studies in stratigraphy, palaeo-
ecology, palaeogeography and systematics.
Akadémiai Kiadó, Budapest.
Báldi, T. 1983. Magyarországi oligocén és alsómiocén
formációk. Akadémiai Kiadó, Budapest.
Báldi, T. 1998. Magyarország epikontinentális oligocén
képződményeinek rétegtana, p. 419-435. In Bérczi, I.
and Jámbor, Á. (eds.), Magyarország geológiai
képződményeinek rétegtana. MOL Rt and MÁFI,
Budapest.
Báldi, T. and Seneš, J. 1975. OM Egerian. Die Egerer,
Pozdraner, Puchkirchner Schichtengruppe und die
Bretkaer Formation. Chronostratigraphie und
Neostratotypen 5. Veda, Bratislava.
Brandt, J.F. 1833. Conspectus monographiae crustaceo-
rum oniscidorum latreillii. Byulleten’ Moskovskogo
Obshchestva Ispytatelej Prirody, 6:171-193.
Broly, P., Deville, P., and Maillet, S. 2013. The origin of
terrestrial isopods (Crustacea: Isopoda: Oniscoidea).
Evolutionary Ecology, 27:461-476.
Broly, P., Maillet, S., and Ross, A.J. 2015. The first ter-
restrial isopod (Crustacea: Isopoda: Oniscoidea)
from Cretaceous Burmese amber of Myanmar. Creta-
ceous Research, 55:220-228.
Brusca, R.C., Coelho, V.R., and Taiti, S. 2007. Isopoda,
p. 503-542. In Carlton, J.T. (ed.), The ight and Smith
Manual: intertidal invertebrates from central Califor-
nia to Oregon, 4th edition. University of California
Press, Berkeley.
Budde-Lund, G. 1885. Crustacea Isopoda Terrestria per
familia et genera et species descripta. Nielsen &
Lydiche, Hauniae [= Copenhagen].

PALAEO-ELECTRONICA.ORG
9
Charmantier-Daures, M. and Vernet, G. 2004. Moulting,
autotomy, and regeneration, p. 161-255. In Forest, J.,
von Vaupel Klein, J.C., and Schram, F.R. (eds.),
Treatise on zoology – anatomy, taxonomy, biology.
The Crustacea, revised and updated from the Traité
de Zoologie 1. Brill, Leiden.
Coulson, S.J., Hodkinson, I.D., Webb, N.R., and Harri-
son, J.A. 2002. Survival of terrestrial soil-dwelling
arthropods on and in seawater: implications for trans-
oceanic dispersal. Functional Ecology, 16:353-356.
Dalens, H. and Bouthier, A. 1985. Oniscoides subfos-
siles trouvés dans une fosse gallo-romaine du IIe siè-
cle après J. C. Bulletin de la Société d’Histoire
naturelle de Toulouse, 121:85-88.
Dávid, Á. 1993. Trace fossils on molluscs from the Mol-
luscan Clay/Late Oligocene, Egerian/ – a comparison
between two localities (Wind Brickyard, Eger, and
Nyárjas Hill, Novaj, NE Hungary). Scripta Geologica,
Special Issue 2:75-82.
Dávid, Á. 1999. Predation by Naticid Gastropods on Late
– Oligocene (Egerian) Molluscs Collected from Wind
Brickyard, Eger, Hungary. Malakológiai Tájekoztató,
17:11-19.
Dávid, Á. 2004. The occurrence of the ichnogenus
Teredolites in Egerian Age Formations from Hungary,
p. 12. In Mikuláš, R. (ed.), 4th International Bioero-
sion Workshop, Prague, August 30-September 3,
2004, Abstract Book. Institute of Geology, Academy
of Sciences, Prague.
Dollfus, A. 1904. Sur un nouveau genre et une nouvelle
espèce de crustacé isopode fossile découvert
à Bouzigues (Herault). Feuille des Jeunes Natural-
istes, (4)34:145-146.
Donlan, C.J. and Nelson, P.A. 2003. Observations of
invertebrate colonized flotsam in the eastern tropical
Pacific, with a discussion of rafting. Bulletin of Marine
Science, 72:231-240.
Dunlop, J.A. 2010. Bitterfeld amber, p. 57-68. In Penney,
D. (ed.), Biodiversity of fossils in amber from the
major world deposits. Siri Scientific Press, Manches-
ter.
Dunlop, J.A., Scholtz, G., and Selden, P.A. 2013. Water-
to-land transitions, p. 417-439. In Minelli, A., Box-
shall, G., and Fusco, G. (eds.), Arthropod Biology and
Evolution. Springer, Berlin/Heidelberg.
Etter, W. 2014. A well-preserved isopod from the Middle
Jurassic of southern Germany and implications for
the isopod fossil record. Palaeontology, 57:931-949.
Feldmann, R.M. 2009. A new cirolanid isopod (Crusta-
cea) from the Cretaceous of Lebanon: dermoliths
document the pre-molt condition. Journal of Crusta-
cean Biology, 29:373-378.
Fodor, R. 2001. Bioeróziós nyomok felső-oligocén
korallokon (Wind-féle téglagyár, Eger)/Bioerosion on
Late Oligocene Corals (Wind Brickyard, Eger). Föld-
tani Közlöny, 130:179-196.
Frankenberger, Z. 1959. Fauna ČSR 14: Stejnonožci
suchozemští – Oniscoidea. Nakladatelství
Československé Akademie Věd, Praha.
Garthwaite, R.L., Lawson, R., and Sassaman, C. 1995.
Population genetics of Armadillidium vulgare in
Europe and North America. Crustacean Issues,
9:145-199.
Guinot, D., Wilson, G.D.F., and Schram, F.R. 2005.
Jurassic isopod (Malacostraca: Peracarida) from
Ranville, Normandy, France. Journal of Paleontology,
79:954-960.
Heer, O. 1865. Die Urwelt der Schweiz. F. Schulthess,
Zürich.
Hegna, T.A. 2010. Photography of soft-bodied crusta-
ceans via drying, whitening, and splicing. Journal of
Crustacean Biology, 30:351-356.
Holthuis, L. 1945. Notes on the Dutch Armadillidiidae
with the description of Armadillidium album Dollfus.
Zoologische Mededeelingen, 25:65-71.
Hornung, E. 2011. Evolutionary adaptation of oniscidean
isopods to terrestrial life: Structure, physiology and
behaviour. Terrestrial Arthropod Reviews, 4:95-130.
Hyžný, M., Bruce, N., and Schlögl, J. 2013. An appraisal
of the fossil record for the Cirolanidae (Malacostraca:
Peracarida: Isopoda: Cymothoida), with a description
of a new cirolanid isopod crustacean from the early
Miocene of the Vienna Basin (Western Carpathians).
Palaeontology, 56:615-630.
Jass, J. and Klausmeier, B. 2000. Endemics and immi-
grants: North American terrestrial isopods (Isopoda,
Oniscidea) north of Mexico. Crustaceana, 73:771-
799.
Kensley, B. and Schotte, M. 1989. Guide to the Marine
Isopod Crustaceans of the Caribbean. Smithsonian
Institution Press, Washington, D.C./London.
Kussakin, O.G. 1979. Marine and brackish-water Isop-
oda of cold and temperate (boreal) waters of the
Northern Hemisphere. Part 1. Flabellifera, Valvifera,
and Tyloidea. National Academy of Sciences,
U.S.S.R., Zoology, 122:1-470. (In Russian)
Kvaček, Z. and Hably, L. 1991. Notes on the Egerian
stratotype flora at Eger (Wind brickyard), Hungary,
Upper Oligocene. Annales Historico-Naturales Musei
Nationalis Hungarici, 83:49-82.
Latreille, P.A. 1802-1803. Histoire naturelle, générale et
particulière, des Crustacés et des Insectes; vol. 3. F.
Dufart, Paris.
Latreille, P.A. 1804. Histoire naturelle, générale et partic-
ulière, des crustacés et des insectes. Cloportides;
vol. 7. F. Dufart, Paris.
Latreille, P.A. 1817. Les crustacés, les arachnides et les
insectes. In G. Cuvier (ed.), Le règne animal distribué
d'après son organisation, pour servir de base à l'his-
toire naturelle des animaux et d'introduction à l'anat-
omie comparée. Déterville, Paris, 653 pp.
Legrand, J.J. 1946. Les coaptations sexuelles des Onis-
coidea. Bulletin Biologique de la France et de la Bel-
gique, 80:241-388.
Morris, S.F. 1979. A new fossil terrestrial isopod with
implications for the East African Miocene land form.
Bulletin of the British Museum (Natural History),
Geology, 32:71-75.

HYŽNÝ & DÁVID: ONISCIDEAN ISOPOD FROM HUNGARY
10
Nagler, C., Haug, C., Resch, U., Kriwet, J., and Haug,
J.T. 2016. 150 million years old isopods on fishes: a
possible case of palaeo-parasitism. Bulletin of Geo-
sciences, 91:1-12.
Neues, F., Ziegler, A., and Epple, M. 2007. The composi-
tion of the mineralized cuticle in marine and terres-
trial isopods: A comparative study. CrystEngComm,
9:1245-1251.
Novák, O. 1872. Über eine neue Isopoden-Gattung aus
dem tertiären Süsswasser-Kalk von Waltsch. Sitzu-
ngsberichte der Königlich Böhmischen Gesellschaft
der Wissenschaften, Mathematisch-naturwissen-
schaftliche Klasse, 1872:39-45.
Perkovsky, E.E., Zosimovich, V.Y., and Vlaskin, A.P.
2010. Rovno amber, p. 116-136. In Penney, D. (ed.),
Biodiversity of fossils in amber from the major world
deposits. Siri Scientific Press, Manchester.
Piller, W.E., Harzhauser, M., and Mandic, O. 2007. Mio-
cene Central Paratethys stratigraphy – current status
and future directions. Stratigraphy, 4:71-88.
Poore, G.C.B. and Bruce, N.L. 2012. Global Diversity of
Marine Isopods (Except Asellota and Crustaceans
Symbionts). PLoS ONE, 7(8): e43529.
Racovitza, E. 1907. Biospéologica. IV. Isopodes terres-
tres (première série). Archives de Zoologie expéri-
mentale et générale, 4eSérie, 7:145-225, pls. 10-20.
Racovitza, E-G. and R. Sevastos. 1910. Proidotea haugi,
n. g. et n. sp., isopode Oligocène de Roumanie, et
les Mesidoteini, nouvelle sousfamille des Idotheidae.
Archives de Zoologie expérimentale et générale,
6:175-200.
Richardson, H. 1905. Monograph on the isopods of
North America. Bulletin of the United States National
Museum, 54:i-xi,1-727.
Sars, G.O. 1899. An account of the Crustacea of Norway.
II, Isopoda. Bergen Museum, Bergen.
Schmalfuss, H. 1985. Zwei bemerkenswerte neue
Landisopoden-Arten von der griechischen Insel Paxi.
Stuttgarter Beiträge zur Naturkunde, Serie A 380:11
pp.
Schmalfuss, H. 1989. Die Land-Isopoden (Oniscidea)
Griechenlands. 10. Beitrag: Gattung Trichodillidium
g. n. (Armadillidiidae). Sitzungsberichte der österre-
ichischen Akademie der Wissenschaften, mathema-
tisch-naturwissenschaftliche Klasse, Abteilung I,
197:207-214.
Schmalfuss, H. 2000. Distributional patterns in the Greek
species of the terrestrial isopod genus Armadillidium
Brandt, 1833. The Belgian Journal of Zoology, 130
(Supplement 1):75-80.
Schmalfuss, H. 2003. World catalog of terrestrial isopods
(Isopoda: Oniscidea). Stuttgarter Beiträge zur
Naturkunde, Serie A, 654:1-341.
Schmalfuss, H. 2013. The species of the genus Armadil-
liidum (Isopoda: Oniscidea) known from Greece.
Stuttgarter Beiträge zur Naturkunde, Serie A, Neue
Serie 6:13-20.
Schmidt, C. 2002. Contribution to the phylogenetic sys-
tem of the Crinocheta (Crustacea, Isopoda). Part 1
(Olibrinidae to Scyphaidae s. str.). Mitteilungen aus
dem Museum für Naturkunde in Berlin (Zoologische
Reihe), 78:275-352.
Schmidt, C. 2003. Contribution to the phylogenetic sys-
tem of the Crinocheta (Crustacea, Isopoda). Part 2
(Oniscoidea to Armadillidiidae). Mitteilungen aus
dem Museum für Naturkunde in Berlin (Zoologische
Reihe), 79:3-179.
Schmidt, C. 2008. Phylogeny of the terrestrial Isopoda
(Oniscidea): a review. Arthropod Systematics & Phy-
logeny, 66:191-226.
Schöbl, J. 1880. Über die Fortpflazung isopoder Crusta-
ceen. Archiv für Mikroskopische Anatomie, 17:125-
140.
Serrano, M.L., Vega, F.J., and Coutiño, M.A. 2007. Ter-
restrial isopods included in Miocene amber from Chi-
apas, Mexico. Geological Society of America,
Abstracts with Programs, 39(6):76-77.
Sfenthourakis, S. and Taiti, S. 2015. Patterns of taxo-
nomic diversity among terrestrial isopods. ZooKeys,
515:13-25.
Spahr, U. 1993. Ergänzungen und Berichtigungen zu R.
Keilbachs Bibliographie und Liste der Bernsteinfossil-
ien. Verschiedene Tiergruppen, ausgenommen
Insecta und Araneae. Stuttgarter Beiträge zur
Naturkunde, Serie B, 194:1-77.
Srivastava, G.P., Shukla, M., Kumar, P., Kumar, M., and
Prakash, A. 2006. Record of pillbug (Armadillidium)
and millipede (Polyxenus) remains from the resin
lumps of Warkali Formation (Upper Tertiary), Kerala
Coast. Journal of the Geological Society of India,
67:715-719.
Steel, C.G.H. 1993. Storage and translocation of integu-
mentary calcium during the moult cycle of the terres-
trial isopod Oniscus asellus (L.). Canadian Journal of
Zoology, 71:4-10.
Strouhal, H. 1956. Zoologische Studien in West-Griech-
enland. VI. Teil. Isopoda terrestrial, II.: Armadillidii-
dae. Sitzingsberichte der österreichischen Akademie
der Wissenschaften, mathematisch-naturwissen-
schaftliche Klasse, Abteilung I, 165:585-618.
Tabacaru, I. 1999. L’adaptation à la vie aquatique d’un
remarquable trichoniscide cavernicole, Cantabronis-
cus primitivus Vandel, et le problème de la monophy-
lie des isopodes terrestres. Travaux de l’Institut de
Spéléologie «Emile Racovitza», 37-38:11-131.
Tait, J. 1917. Experiments and observations on Crusta-
cea. Part II. Moulting of isopods. Proceedings of the
Royal Society of Edinburgh, 37:59-68.
Taiti, S, Ferrara, F., and Schmalfuss, H. 1991. Evolution
and biogeography of the family Eubelidae (Crusta-
cea, Oniscidea), p. 23-30. In Juchalt, P. and Moc-
guard, J.P. (eds.), Biology of Terrestrial Isopods III
(Third International Symposium on the Biology of
Terrestrial Isopoda 1990). Université de Poitiers, Poi-
tiers.
Tauber, A. F. 1950. Sphaeroma bachmayeri nov. sp.,
eine Schwimmassel aus dem Torton des Wiener
Beckens. Sitzungsberichte der Österreichischen

PALAEO-ELECTRONICA.ORG
11
Akademie der Wissenschaften, mathematisch-natur-
wissenschaftliche Klasse, Abteilung I, 159:101-108.
Van Name, W.G. 1936. The American Land and Fresh-
Water Isopod Crustacea. Bulletin of the American
Museum of Natural History, 71:1-535.
Vandel, A. 1961. Les isopodes terrestres de l'Île de
Minorque. Archives de Zoologie expérimentale et
générale, 4e Série 99: 249-265.
Vandel, A. 1962. Isopodes terrestres (deuxième partie),
pp. 417-931. In Faune de France, 66. P. Lechevalier,
Paris.
Vega, F J., Bruce, N.L., Serrano, L., Bishop, G.A., and
Perrilliat, M. del C. 2005. A review of the Lower Cre-
taceous (Tlayúa Formation: Albian) Crustacea from
Tepexi de Rodríguez, Puebla, Central Mexico. Bulle-
tin of the Mizunami Fossil Museum, 32:25-30.
Verhoeff, K.W. 1900. Über paläarktische Isopoden (2.
Aufsatz). Zoologischer Anzeiger, 23:117-130.
Verhoeff, K.W. 1901. Über paläarktische Isopoden (3.
Aufsatz). Zoologischer Anzeiger, 24:33-41.
Verhoeff, K.W. 1918. Ueber augenlose Armadillidien und
kritische Prüfung der Familie Armadillidiidae. Archiv
für Naturgeschichte, 8A:160-170.
Verhoeff, K.W. 1919. Zur Kenntnis der Gattungen Porcel-
lium und Armadillidium in Deutschland. Archiv für
Naturgeschichte, 83A:1-37.
Verhoeff, K.W. 1939. Über einige balkanische Isopoda
terrestria (69. Isopoden-Aufsatz). Studien aus dem
Gebiete der allgemeinen Karstforschung, der wissen-
schaftlichen Höhlenkunde, der Eiszeitforschung und
den Nachbargebieten, B. Biologische Serie, 6:5-10.
Vernet, G. and Charmantier-Daures, M. 1994. Mue, auto-
tomie et régénération, p. 153-194. In Grassé, P.-P.
(ed.), Traite de Zoologie. Anatomie, systématique,
biologie. Tome 7: Crustacés. Fascicule 1: Morpholo-
gie, physiologie, réproduction, systématique. Mas-
son, Paris.
von Ammon, L. 1882. Ein Beitrag zur Kenntniss der fos-
silen Asseln. Sitzungsberichte der mathematisch-
physikalischen Classe der königlich Bayerischen
Akademie der Wissenschaften, 4:507-550.
Wägele, J.-W. 1989. Evolution und phylogenetisches
System der Isopoda. Stand der Forschung und neue
Erkentnisse. Zoologica, 140:1-262.
Warburg, M.R. 1993. Distribution Patterns of Isopod
Species in Different Habitats, p. 70-84. In Warburg,
M.R. (ed.), Evolutionary Biology of Land Isopods.
Springer, Berlin Heidelberg.
Weitschat, W. and Wichard, W. 2010. Baltic amber, p.
80-115. In Penney, D. (ed.), Biodiversity of fossils in
amber from the major world deposits. Siri Scientific
Press, Manchester.
Wilson, G.D.F., Paterson, J.R., and Kear, B.P. 2011. Fos-
sil isopods associated with a fish skeleton from the
Lower Cretaceous of Queensland, Australia – direct
evidence of a scavenging lifestyle in Mesozoic
Cymothoida. Palaeontology, 54:1053-1068.
Zenker, C. 1798. [Descriptions of Oniscus pulchellus and
Oniscus cinereus], p. 21-22. In Panzer, G. (ed.), Fau-
nae insectorum Germanicae initia, oder Deutsch-
lands Insecten 62. Felsecker, Nürnberg.