Table Of ContentTHE NAUTILUS 128(2):59-63, 2014 Page 59
First American record of the exotic slog Tandonia kusceri
(Gastropoda: Milacidae)
Joclieii Gerber
—
Collections Center Invertel)rates
Field Museum ofNatural Histor>'
1400 South Lake Shore Drive
Chicago, IL60605-2496 USA
jgerber@riekliniiseiiin.()rg
ABSTRACT introduction, are more likely to be successful if intro-
duced species are documented as earlyas possible (Reise
Theterrestrial slugTandonia kusceri (Pulmonata: Milacidae) is et ah, 2000; 2006; Robinson and Slapcinsky, 2005).
native to the Balkan Peninsula. This article reports the discov- In this article, the first American record of tlie alien
ery of the species for the first time outside southeastern
Europe, in Brookfield, Illinois, USA, a suburb of Chicago. slug Tandonia kusceri (H. Wagner, 1931) is reported.
Descriptions and photographs oflive animals and reproductive Photographs and descriptions ofthe animal and its gen-
organs are proMded to facilitate the recognition ofthis poten- ital anatomy are provided as identification tools.
tial pest species preciously unrecorded from the Americas.
Tandonia kusceri is compared with three other Milacidae spe- MATERIALS AND METHODS
cies that have been introduced by humans into regions out-
side their native range, two of which have been recorded
from North America. The known distribution and ecology of Voucher material has been deposited in the Mollusk
T. kusceri are summarized. CCohlilceacgtoion(FoMfNtHhe) Faineldd tMheusUeuSmDAofNaNtaitounraall MHiosltloursyk,
Additional Keijivords: Introduced species, genital anatomy Collection, Philadelphia (USDA):
USA, Illinois, Cook County, Brookfield, nearthe inter-
section ofJefferson and Harrison Avenues, 41°49'42" N,
87°51'23" W, 190 m a.s.h, crawling on concrete porch
after rain, at about 23:00h, 21 June 2013, leg. M.K.
INTRODUCTION Thayer (FMNH 328572: 8 specimens preserved in 70%
ethanol -b tissue samples of 5 of these specimens in
Terrestrial slugs have a long history ofbeing introduced 95% ethanol; USDA 140056: 2 specimens preseiwed in
to the Americas from other continents. At least 26 spe- 70% ethanol).
cies have been reported as having established popula- Same locality, but found in front yard, buried 10 cm
tions in the USA and Canada (Turgeon et ah, 1998; deep in garden soil; 5 October 2013, leg. M.K. Thayer
Reise et ah, 2000, 2006; Grimm et ah, 2009). Introduced (FMNH 328573: 1 specimen in 70% etlianol; FMNH
slugspecies can pose threats to the environment, e.g., by 328574: 1 dried specimen [mummified afterescape from
competing with native species (RoIIo, 1983), and they container in which specimens were kept]).
can become important agricultural pests (Me Donnell
et ah, 2009 and references therein). Consequently, con-
IDENTIFICATION
siderable amounts ofmanpower and money are spent by
governments (e.g., U.S. Department of Agriculture The descriptions (Figures 1^) given here are based on
[USDA]) to prevent additional species from entering
the Brookfield specimens ofT. kusceri.
North America, to limit the spread, and, if possible,
eradicate limited occurrences of newly introduced spe- External Morphology; Fully extended, mature spec-
cies. Nevertheless, ever-increasing international trade imens ca. 7 cm long, rather slender. Length of mantle
has the unfortunate side effect that additional alien slug shield in the front half of the body about % total body
species (alongwith othermollusks and other animals and lengtli. Breathing pore at about ofthe mantle length
plants) continue to be introduced to America (Robinson, from the anterior mantle margin, on the right side ofthe
1999; Robinson and Slapcinsky, 2005). Efforts to prevent mantle shield. Mantle shield with a horseshoe-shaped
new introductions and to limit the spread of alien spe- groove open posteriorly. Surface of mantle shield gran-
cies, as well as attempts to discover the avenues oftheir ular. A keel extends along the middle of the dorsum.
Page 60 THE NAUTILUS, Vol. 128, No. 2
Figures i-4. Tandotiia kusceri from Bolingbrook, Illinois, USA (F’MNH 328572). 1. Extended specimen, length about 6.5 cm.
2. Contractedspecimen. 3. Animal with sole exposed. 4. Distal portion ofthe reproductivetract. Abbrexiations: ag, accessorygland;
at, genital atrium; be, bursa copulatrix; bd, duct of bursa copulatrix; dep, distal part of epipluillus; dp, distal part of penis;
er, epiphallus retractor; ov, oxiduct; pep,proximal partofepiphallus; pp, proximal partofpenis; pr,penis retractor; vd,vasdeferens.
Gerber, 2014 Page 61
J.
from tlie tail end to the posterior edge of the mantle Ecology: According to Wiktor (1987), T. kusceri is a
shield. Back and sides with about 15 diagonal rows “species of veiy liigli ecological tolerance*, occurring in
offlattened tubercles on each side. When resting, spec- biotopes ofvarious liumiditv, most often found in places
imens can contract strongly antero-posteriorly, so of large quantity of loo.se stones, under which it shel-
as to attain nearly a half-circle shape when seen from ters. (Jeeurring in shrubs, woods, stone debris, and
tlie side. .synantbropically. Usually in large numbers, especially on
Overall color light yellowish- to pinkish-brown, becom- limestone, and in biotopes heavily destroyed by man
ing lighter toward the sole. Black pigment concentrated (wasteliUid, dumps, ruins).” Recorded elevations range
in the furrows separating the skin tubercles, which from sea level (e.g., Varna, Bulgaria and Odessa, Uknune;
results in a reticulated pattern. Keel lighter-colored Wiktor, 1983; 1987; Son, 2010) to 1450 in a.s.l. (Osogovo
than back, without black pigment. Mantle diffusely Mountiiins, FYR Macedonia; Dedov and Mitev, 2011).
speckled with dark pigment. A dark band present on Welter-Schultes (2012) states that T. kusceri occurs
either side along the branches ofthe horseshoe groove. “in Bulgaria in up to 2000 m.” However, none of the
Another, somewhat less distinct longitudinal pigment references he gives contains siicli an elevation record
band in the center of the mantle shield. Head and and it is unclearon what this statement is based.
tentacles brownish-grey. Sole tripartite, uniformly pale According to observations at the B()ling!)r()()k site,
yellowish, without dark pigment. Mucus of body and T. kusceri is only active at night. On 5 October 2013 two
sole colorless, transparent, slightly milky when ani- specimens were discovered duringthe day, buried 10 cm
mal irritated. deep in garden soil. One of the specimens collected in
October 2013 was held captive until late March 2014.
Genitalia: Ovotestis in the dissected specimens (n=2) The specimen was strictly nocturnal in its habits. During
large, suggesting sexual maturity. Hermaphroditic duct the dayit stayed buried in the soil coveringtlie bottom of
long and thin. Albumen gland large (again, suggesting the container rather than using items like pieces of tree
sexual maturity), elongated andbent. Spermoviductwide bark that were offered for shelter.
and twisted. Vas deferens thin and almost i.5 times as
long as penis and epiphallus combined, opening apically
into the conically attenuated proximal end of the DISCUSSION
epiphallus. Epiphallus tubular, wider distally than proxi-
mally, very long, about five times as long as the penis, Several species in the Milacidae, namely Milax gfigaies
intensely coiled and twisted. A broad retractor muscle (Draparnaud, 1801), Tandonia budapestensis (Hazay,
inserting on the epiphallus about 'A ofits length from its 1881) and Tandonia soiverhiji (A. Ferussac, 1823), are
proximal end. Boundary between epiphallus and penis known as invasives in areas farbeyond theirnative south-
marked by the insertion ofa thin second retractor mus- ern European range. Milax gagates has been introtliiced
cle. Penis with two distinct sections: a tubular proximal around the world including North and South America
part about as wide as the distal epiphallus or hardly (Wiktor, 1987; Turgeon et al., 1998; Grimm et al., 2009;
wider, and a distal part that is short and globular, about McDonnell et al., 2009) and T. budapestensis has lieen
twice as wide as the proximal part. recorded in the eastern United States (Reise et al.,
Oviduct tubular, straight or but lightly bent. Bursa 2006). Consequently, it seemed likely that the milacids
copulatrix large, spherical. Bursa duct thick, its diameter from Brookfield belonged to one oftliese tramp species.
slightly more than '/r of the bursa diameter, and about However, the attempt to assign the specimens to one of
twice as long as the bursa. these species based on external characters failed. Dissec-
Accessoryglands are twocrinkled lobes, one roundish, tions clearly showed that the Brookfield specimens
the otherelongated, that are attached to thevaginaat the were not conspecific with any of these invasives, but
transition to the oviduct and bursa duct. The glands are that theyinstead belonged to Tandonia kusceri, a species
of a beige color (as opposed to the white surrounding that had not been found previously outside of south-
reproductive organs). Vagina and atrium short. eastern Europe.
Epiphallus and bursa copulatrix with its duct were The combination of an extremely long vas deferens
examined for the presence ofa spermatophore but none and epiphallus, the latter being intensely coiled and
was observed. twisted, a short, bipartite penis, and a large, bulbous
bursa with a thick tubular duct is unicpie among the
Distributioo: The native distribution area ofT. kusceri Milacidae and allows for easy recognition of T. kusceri.
lies in the Balkans. It stretches from Central Serbia Figure 4 shows the distal parts ofthe reproductive tract
through FYR Macedonia, northeastern Greece, and of a specimen from Bolingbrook (FMNH 328572). It
Bulgaria to European Turkey and Southeast Romania resembles Wiktors (1987: 258-259, fig. 155) description
(Dedov and Mitev, 2011; Reischiitz, 1988; Wiktor, 1987; and drawing of the genital anatomy of T. kusceri very
2001). Occurrences of the species in Croatia, coastal closely. The only differences are: W'iktor shows a con-
Southwest Ukraine, and Crimea are presumed to be the striction at the insertion of the penis retractor, i.e., at
result of human introductions (Son, 2010; Sysoev and the epiphallus-penis boundary'. No such constriction is
Schileyko, 2009; Wiktor, 1987; 1996). discernible in the Bolingbrook specimen. Secondly, the
Page 62 THE NAUTILUS, Vol. 128, No. 2
broad retractor inserting on the epiphallus about 'A of At this point it is not clear ifthe T. kusceri population
its length from its proximal end is neither mentioned in Brookfield is the result of a recent introduction and
nor figured by Wiktor. However this feature is depicted restricted to the immediate area around the collection
in two of the drawings of the genitalia of T. kusceri (as site, or if the species has been there for a number of
Milax [M. kusceri) by Grossii (1983: 223, fig. 139; 124, years and occupies a wider area. We do not know how
]
fig. 140). this exotic species was introduced. The fact that the
Externally, the Bolingl)rook specimens agree w4th the discoverer, Dr. Margaret K. Thayer, who has lived at this
description ofT. kusceri given by Wiktor (1987). Wiktor address for the last 25 years and who, as an experienced
states that extended specimens are up to 10cm long. The zoologist, is trained to take notice of unusual animal
specimen figured by him (1987: 258, fig. 154) measures occurrences, does not remember seeing this slug in pre-
about 6.5 cm. vious years seems to point to a recent arrival on the
Otlier milacid species recorded from North America Thayer property. However, it is currently impossible to
differ as follows (Wiktor, 1987): state wdth certainty whether the slugs have recently
migrated from nearby yards and gardens where they
Milax ^agates - Vas deferens short; epiphallus club- may have dwelled for some time and howand when they
shaped, proximally truncated, short; penis irregularly arrived there. I intend to monitor the Tandonia popula-
rounded, short, almost halfthe length ofthe epiphallus; tion in Bolingbrook and learn more about the extent of
bursa copulatrix elongated, its duct very short and indis- the infestation in the coming months.
tinct; accessory glands open into the atrium (not the The apparently verv wide ecological amplitude of
\'agina) through numerous tubules (characteristic for T. kusceri and its synanthropic tendencies (Wiktor,
genus Milax); atrial stimulator present (cliaracteristic for 1987) suggest that the species could be successful in
genus Milax). Body tends to be uniformly dark grey or l)ecomingestablished in North America.
blackish, without pigment spots.
ACKNOWLEDGMENTS
Tandonia hudapestensis - Vas deferens short;
epiphallus short, as long as or slightly longer than penis, Thanks are due to Dr. Margaret K. Thayer (FMNH-
cylindrical or club-shaped; penis irregularly rounded; Insects) for bringing the slugs to my attention, for
bursa copulatrix oval to cylindrical, its duct thick and collecting specimens and for sharing her slug-related
short. Body appearing variably blackish-broum due to observations witli me.
dense black spotting on a dull cream or orange back-
ground; keel olive or orange, without black pigment.
Wlien resting, animals often curl into a c-shape, as LITERATURE CITED
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