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Amer. Malac. Bull. 36(2): 232–247 (2018)
232
Public participation in scientifi c research (Bonney et al.
2009, Theobald et al. 2015), known as citizen or community
science (Bonney et al. 2014, Eitzel et al. 2017), allies the public
with scientists in a collaborative pursuit of scientifi c data.
Projects with a contributory design accelerate the collection
of biodiversity data through voluntary participation of non-
specialists or non-professionals who make photographs of
the natural world available to researchers (Dickinson et al.
2012, Shirk et al. 2012, Bonney et al. 2014). These photo-
graphs, as species observations, are often taken with smart-
phones that tag each image with precise location coordinates.
When these images are contributed to online biodiversity
platforms like eBird, iSpotnature, or iNaturalist they can
become valuable to biologists as geo-referenced data points
(Pimm et al. 2015, Bik 2017, Clark 2017). When biodiversity-
themed contributory citizen science projects involve a natural
history museum (NHM) there is an additional opportunity
to collect, preserve, and house voucher specimens for research,
exhibit, and education.
Five new records of introduced terrestrial gastropods in southern California discovered
by citizen science
Jann E. Vendetti1, Cedric Lee2,3, Pat LaFollette2,3, and citizen science participants in SLIME3 and
BioSCAN4
1Malacology Department and Urban Nature Research Center (UNRC), Natural History Museum of Los Angeles County, 900 Exposition
Blvd., Los Angeles, California 90007, U.S.A. JVendett@nhm.org
2Museum Associate, Malacology Department, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles,
California 90007, U.S.A.
3Snails and slugs Living in Metropolitan Environments (SLIME), Natural History Museum of Los Angeles County, 900 Exposition Blvd.,
Los Angeles, California 90007, U.S.A., iNaturalist website: www.inaturalist.org/projects/slime, additional contributing participants: Alex
Bairstow, Devon Escobar, Kat Halsey, Emily Han, Gregory Han, Isabella Hayden, Christina Kastely, Barbara Jeanne Lloyd, Cathy McNassor,
Sharon Nakata, Erik Pogosyan, B.J. Stacey, and Isaiah Sanchez
4Biodiversity Science: City And Nature (BioSCAN), Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles,
California 90007, U.S.A. Contributing participants: Lascano family
Abstract: Terrestrial gastropod inventories can be improved, both in scope and thoroughness, by including species observations made by
citizen scientists. Few citizen science projects, however, focus on terrestrial gastropods and perhaps none has mobilized members of the
public to survey the malacofauna of a major North American metropolitan area. Here we report fi rst occurrence records of fi ve introduced
terrestrial gastropod species in the metropolitan areas of Los Angeles, Orange, and Riverside counties in California, discovered by citizen
science: Arion hortensis Férussac, 1819, Cochlicella barbara (Linnaeus, 1758), Lauria cylindracea (Da Costa, 1778), Pupoides albilabris (C.B.
Adams, 1841), and Xerotricha conspurcata (Draparnaud, 1801). Four of these taxa are known elsewhere in California and one, L. cylindracea,
is a fi rst occurrence record for the U.S.A. All were contributed to SLIME, a citizen science project and malacofaunal inventory of southern
California initiated by the Natural History Museum of Los Angeles County and hosted online by iNaturalist. Species identifi cations were
made based on snail or slug morphology and collected specimens’ COI barcoding sequences, which were compared to those in GenBank and
BOLD databases. These discoveries demonstrate the effi cacy of SLIME and the potential for molluscan-focused citizen science to detect and
document land snail and slug taxa in a major metropolis.
Key words: Los Angeles, urban biodiversity, bioblitz, land snail, community science
Here we report fi ve fi rst occurrence records of intro-
duced terrestrial gastropod species in southern California
that were documented by citizen science: Arion hortensis
Férussac, 1819, Cochlicella barbara (Linnaeus, 1758), Lauria
cylindracea (Da Costa, 1778), Pupoides albilabris (C.B. Adams,
1841), and Xerotricha conspurcata (Draparnaud, 1801). The
discovery of L. cylindracea is the fi rst vouchered record of this
species in the U.S.A., X. conspurcata and A. hortensis are fi rst
records for Los Angeles County, C. barbara is a fi rst record
for Los Angeles and Orange counties, and P. albilabris is a
fi rst record for Riverside County, California. All were found
in anthropogenically-altered habitats by contributors to SLIME
(Snails and slugs Living in Metropolitan Environments), a
malacofaunal survey initiated by the Natural History Museum
of Los Angeles County (NHMLA) and hosted online by
iNaturalist (www.inaturalist.org/projects/slime). Live-collected
specimens were sequenced for the mtDNA barcoding gene
COI, and preserved and deposited in the NHMLA Malacology
collection. Specimen identifications were made based on
SNAILS DOCUMENTED BY CITIZEN SCIENCE 233
body and/or shell morphology and specimens’ COI sequences
were compared to those in GenBank and BOLD databases.
Notably, four of these taxa, A. hortensis, C. barbara, L. cylind-
racea, and X. conspurcata, are considered “traveling species”
by Robinson (1999), a designation for terrestrial gastropods
that have been transported widely and are established beyond
their native ranges.
Citizen science and mollusks – present efforts and potential
The most popular regional and worldwide citizen science
projects with a contributory design (Shirk et al. 2012) and
taxonomic focus (with >20,000 observations) document birds,
reptiles and amphibians, charismatic insects, and mushrooms
(e.g. ebird.org, herpmapper.org, e-butterfl y.org, and mush-
roomobserver.org). Overall, molluscan-themed projects have
been diverse but relatively few in number (Table 1), even
though many molluscan groups would be well-suited to citi-
zen science. Moreover, because terrestrial and freshwater gas-
tropod biodiversity is under-reported in many parts of the
world (Reise et al. 2006, Araiza-Gómez et al. 2017), and spe-
cies are regularly introduced by the commodities trade
(Capinha et al. 2015), malacofaunal inventories could be
more accurate, thorough, and easily updated by including
volunteer surveyors and/or crowd-sourced data (Cohn 2008,
Aravind 2013, Adriaens et al. 2015, USEPA 2016, Aravind
2017). Indeed, on public land, bioblitzes, or short-term bio-
diversity inventories (Cohn 1996), have successfully directed
citizen scientists’ effort towards detecting terrestrial and
freshwater gastropods that are rare or newly introduced
(Forsyth 2015, McAlpine et al. 2016, Topley 2017), live in
poorly-surveyed regions (Pearce 2009, Van Devender et al.
2012), or are of conservation concern or pest status (Michalak
and Price 2010).
With the addition of residents and property owners in
surveying efforts, biodiversity inventories could, importantly,
include species records from sites that would be otherwise
inaccessible to scientists (e.g. residential backyards) (Ballard
et al. 2017, Spear et al. 2017). In urban and suburban settings,
Table 1. Citizen science initiatives with a molluscan theme or that include mollusks. Projects are listed by their habitat emphasis (aquatic,
marine, and terrestrial), in chronological order by project start year, and with names in bold indicating re-occurring or on-going surveys. All
are contributory in design except ReClam the Bay, which was co-created (Shirk et al. 2012).
Project, habitat focus,
and (duration) Region Species of focus
Website and/or relevant
references
Aquatic mollusk-focused
Distribution survey of Pomacea
canaliculata (2017+)
Asia: Japan, Osaka and adjacent
prefectures
Pomacea canaliculata (Lamarck,
1822)
sites.google.com/site/sukumiringo
Marine mollusk-focused
Ellenic Network of Aquatic
Invasive Species: ELNAIS
(2001+)
Europe: Coast of Greece and
Greek islands
Any marine organism, including
gastropod Aplysia dactylomela
Rang, 1828
elnais.hcmr.gr, Zenetos et al.
2013, Zenetos et al. 2015,
Poursanidis and Zenetos 2013
Cape Cod National Seashore’s
Estuarine Monitoring
Program (2005)
North America: Massachusetts,
Cape Cod National Seashore
Mostly gastropods and bivalves
including Mya arenaria
Linnaeus, 1758
Thelen and Thiet 2008
ReClam the Bay (2005+) North America: Coast of New
Jersey
Bivalves including Mercenaria
mercenaria (Linnaeus, 1758)
Bonney et al. 2009a reclamthebay.
org
Reef Check California (2006+) North America: California coast >30 species, including gastropod
Megastraea undosa (Wood,
1828)
www.reefcheck.org/california/
ca-overview, Freiwald and
Wisniewski 2015
Xenostrobus securis eradication
in Avilés estuary (2015)
Europe: Avilés estuary in
Asturias, Spain
Xenostrobus securis (Lamarck,
1819)
Miralles et al. 2016
GROC (Catalan Opisthobranch
Research Group)(2016+)
Europe: Coast of Balearic
Islands and Catalonia, Spain
Heterobranch gastropods
including Aplysia dactylomela
Rang, 1828
Moles et al. 2017, opistobranquis.
org/es/home
Terrestrial mollusk-focused
Evolution MegaLab (2009+) Europe: Various terrestrial
habitats
Cepaea nemoralis (Linnaeus,
1758) and Cepaea hortensis
(Müller, 1774)
evolutionmegalab.org, Silvertown
et al. 2011, Cameron 2013
SLIME: Snails and slugs Living
in Metropolitan Environments
(2015+)
North America: southern
California, especially urban
areas
Terrestrial gastropods www.inaturalist.org/projects/slime
234 AMERICAN MALACOLOGICAL BULLETIN 36
· 2
· 2018
these and other anthropogenically-altered localities (e.g. parks,
vacant lots, school campuses) have great potential for synan-
thropic gastropod discovery as they are at the intersection of
people who can make species observations and the habitat of
native and/or introduced species (Haaland and van den
Bosch 2015, Spear et al. 2017). Awareness of synanthropic
terrestrial gastropod populations is also useful to researchers
and pest management agencies, as scientifi c interest in the
responses of species to urbanization has grown in recent years
as well as concern about the introduction of pestiferous taxa
(Beninde et al. 2015, Ives et al. 20 16, Mc Do nne ll and Ma cG reg or -
Fors 2016, Alberti et al. 2017, Brown and Hartop 2017, Johnson
and Munshi-South 2017, Kesner and Kumschick 2018).
SLIME at NHMLA
Snails and slugs Living in Metropolitan Environments
(SLIME) began at NHMLA in August 2015 as a contribution-
based citizen science inventory of land snails and slugs in
southern California. Its geographic scope spans the counties
of Imperial, Kern, Orange, Los Angeles, San Bernardino, San
Diego, San Luis Obispo, Santa Barbara, Riverside, and Ventura.
Species observations are contributed as photos through
iNaturalist, and/or voucher specimens are accepted by the
NHMLA Malacology collection. SLIME was modeled after
another NHMLA-sponsored citizen science project called
RASCals (Reptiles and Amphibians of southern California,
Pauly et al. 2014, Pauly et al. 2015) that is also hosted on
iNaturalist (www.inaturalist.org/projects/rascals). SLIME has
been promoted to the public using social media (NHMLA on
Facebook and Twitter), a blog (www.nhm.org/nature), yearly
bioblitz events (e.g. SnailBlitz 2018), and multi-annual com-
munity meet-ups coordinated by NHMLA’s Community
Science Program. As a result of SLIME and the efforts to pro-
mote it, biologists at NHMLA have the infrastructure to
detect recent terrestrial gastropod introductions in the
region.
MAT ERIALS AND METHODS
Specimen collection and identifi cation
The fi ve terrestrial gastropod species discussed herein
(Table 2) were collected actively by the following co-authors
and citizen scientists, D.E., K.H., E.H., G.H., I.H., C.K., P.L.,
C.L., C.M., S.N., E.P., I.S., and J.E.V., and passively by the
Lascano family whose backyard hosted a Malaise trap for the
BioSCAN (Biodiversity Science: City and Nature) project, an
NHMLA-sponsored insect collecting survey (Brown et al.
2014, Hartop et al. 2015) that inadvertently trapped X. cons-
purcata snails. All collected gastropod specimens were depos-
ited in NHMLA’s Malacology collection and catalogued
with lot numbers preceded by LACM. Specimen or species
observation photo vouchers posted to iNaturalist are desig-
nated herein by “iNat” followed by the unique number of
that observation’s url (e.g. iNat 2602677 for www.inaturalist.
org/observations/2602677).
Species identifi cation of collected terrestrial gastropod
specimens and iNaturalist photo vouchers were made or con-
fi rmed by co-authors J.E. Vendetti, C. Lee, and Malacology
collections manager L. Groves, based on shell characters and/
or external body morphology following the species accounts
in Welter-Schultes (2012), Grimm et al. (2009), and Kerney
and Cameron (1979). For slugs, a tentative identifi cation of
Arion sp. was replaced by A. hortensis after DNA was com-
pared to arionid records in GenBank and BOLD databases
and/or reproductive morphology was examined by co-author
C. Lee and interpreted following Mc Donnell et al. (2009) and
Rowson et al. (2014b).
Specimen microscopy and photography
Arion hortensis slugs intended for dissection were killed
by drowning in water for 4–6 hours, then transferred to and
stored in 75% ethanol. Dissections were performed using a
Wild Heerbrugg M5A (Switzerland) or Nikon SMZ1000
(Japan) stereomicroscope. Scanning electron microscopy
(SEM) was used to image the granular micro-protuberances
on the apertural denticle of L. cylindracea. One shell (LACM
179780) was mounted on an SEM stub with conductive tape,
coated with gold/palladium (60:40) at 0.014 kÅ by an Emitech
K550x sputter coater (Kent, United Kingdom), and imaged
with a Hitachi S-3000N SEM (Tokyo, Japan) at an accelerat-
ing voltage of 10 kV and working distance of 16.3 mm in the
NHMLA Scanning Electron Microscopy Laboratory. A
Keyence VHX-5000 digital microscope (Osaka, Japan) was
used to photograph shells and shell details in C. barbara, L.
cylindracea, P. albilabris, and X. conspurcata. Digital images
and photomicrographs were adjusted in Preview v. 8.0 in
MacOS X for contrast and brightness only.
DNA extraction, amplifi cation, and sequencing
Foot tissue for DNA extraction was sampled from col-
lected specimens of all fi ve species after individuals were
relaxed and killed by immersion in carbonated water for 1–2
hours then transferred to and stored in 95% ethanol. Total
genomic DNA was extracted using the Qiagen DNeasy Blood
& Tissue Kit (Qiagen Corp; Valencia, CA) following the man-
ufacturer’s instructions. Amplifi cation by polymerase chain
reaction (PCR) used universal invertebrate primers for the
mitochondrial DNA gene cytochrome c oxidase subunit 1
(COI): LCO1490 and HCO2198 (Folmer et al. 1994).
Amplifi cation reactions used GoTaq® Green Master Mix
(Promega; Madison, WI), a pre-mixed reagent solution for PCR,
in 25µl total volume reactions with 1–2µl of isolated DNA,
and proceeded as follows: a two-minute initial denaturation
SNAILS DOCUMENTED BY CITIZEN SCIENCE 235
Table 2. Taxon, NHMLA (LACM) specimen number, fi rst occurrence record, collection data, locality, iNaturalist number, and GenBank
accession number for specimens of A. hortensis, C. barbara, L. cylindracea, P. albilabris, and X. conspurcata collected in southern California.
Specimen lots are ordered chronologically by collection date. A dash indicates no iNaturalist number or COI sequence for that specimen; an
asterisk (*) indicates the collector is not a citizen scientist.
LACM no. Collector iNat. no. Collection date GenBank COI acc. no.
Collection locality in southern California and
fi rst occurrence record
Arion hortensis Férussac, 1819 Los Angeles County
179178
C. Lee –10-Mar-16
MG190382 UCLA campus, near Election Walk, Los Angeles
179180 MG190383 UCLA campus, near Election Walk, Los Angeles
179164 MG190384 UCLA campus, near Anderson courtyard, Los Angeles
179162 MG190385 UCLA campus, near Anderson courtyard, Los Angeles
179163 MG190386 UCLA campus, at Women’s Softball fi eld, Los Angeles
179179 MG190388 Sunset Blvd. at S. Bentley and Greenfi eld, Los Angeles
179181 13-Mar-16 MG190390 McPherrin Ave. near Garcelon Ave, Monterey Park
180322 4554285 8-Nov-16 – Bellagio and De Neve Dr., Los Angeles
2017-8.4 J.E. Vendetti* 8712051 2-Nov-17 MG813876 UCLA campus, near Powell Library, Los Angeles
Cochlicella barbara (Linnaeus, 1758) Los Angeles County and Orange County
180088 S. Nakata – 11-Nov-15 – Orange Co., near 23701 Moulton Pkwy, Laguna Hills
180085 E. and G. Han – 1-Feb-16 – L.A. Co., near Quail and Glenalbyn Dr., Los Angeles
179412 13-May-16 MG195978 L.A. Co., near Quail and Glenalbyn Dr., Los Angeles
180089 S. Nakata – 11-Nov-16 – Orange Co., near 23501 Via Mariposa E., Laguna Hills
180133 4548819 12-Nov-16 – Orange Co., near 23701 Moulton Pkwy, Laguna Hills
Lauria cylindracea (Da Costa, 1778) Los Angeles County and U.S.A.
179780
C. Lee
2602677 20-Jan-16 KX756234 UCLA campus, near Election Walk, Los Angeles
180086 3862136 11-Aug-16 – UCLA campus, west of Fowler Museum, Los Angeles
180087 3862135 1-Sep-16 – UCLA campus, near Election Walk, Los Angeles
2017-8.1 J.E. Vendetti* 8712053 2-Nov-17 MG813887 UCLA campus, at Powell Library, Los Angeles
Pupoides albilabris (C.B. Adams, 1841) Riverside County
179582 P. LaFollette* – 20-Feb-17 MG813888 Near Grandview Ave. and Vista Dr., Cathedral City
179582 20-Feb-17 MG813889 Near Grandview Ave. and Vista Dr., Cathedral City
Xerotricha conspurcata (Draparnaud, 1801) Los Angeles County
178850 C. McNassor – 10-Aug-15 – Between Washburn Rd. and Avenue 63, Pasadena
178920
E. and G. Han
– 1-Feb-16 – Near Quail Dr. and Glenalbyn Dr., Los Angeles
180400 2616486 1-Feb-16 KX577716 Near Quail Dr. and Glenalbyn Dr., Los Angeles
178919 – 2-Feb-16 – Near Quail Dr. and Glenalbyn Dr., Los Angeles
179352 D. Escobar
I. Sanchez – 16-Mar-16 KX577717 Arroyo Seco Museum Science Magnet, Los Angeles
179361 Lascano family – ?- Apr-16 – Near Teresa and Bailey Ave., Rosemead
178921 E. and G. Han 2911675 14-Apr-16 – Near Quail Dr. and Glenalbyn Dr., Los Angeles
179032 K. Halsey and
C. Lee 4467421 1-Nov-16 MG813890 At Solano Ave. and Bouett St., Los Angeles
179351 E. Pogosyan 4936439 12-Jan-17 MG813891 San Gabriel Bldg., Glendale Com. College, Glendale
180083 C. Lee 5140224 19-Feb-17 – At W. Frontenac and W. Ave. 45, Los Angeles
179606 C. McNassor – 1-Apr-17 MG813893 Between Washburn Rd. and Avenue 63, Pasadena
2017-4.2 C. Kastely – 8-Apr-17 – Near hilltop along Chadwick Circle, Los Angeles
179779 I. Hayden – 12-Apr-17 MG813892 Near Monrovia High School, Monrovia
step at 94 °C, 40 amplifi cation cycles at 94 °C for 30s (dena-
turation), 40 °C for 45s (annealing), 72 °C for 60s (exten-
sion), with a fi nal extension step at 72 °C for 7 mins. PCR
products were verifi ed by gel electrophoresis using a 1%
agarose gel containing ethidium bromide, then purifi ed and
sequenced in both directions by Retrogen, Inc. (San Diego, CA)
using PCR primers. Resulting chromatograms were inspected
for quality, aligned, trimmed of primers in Geneious® version
236 AMERICAN MALACOLOGICAL BULLETIN 36
· 2
· 2018
8.1.6 (Kearse et al. 2012), and submitted to GenBank.
Specimen collector, collection localities, NHMLA Malacology
collection lot numbers and GenBank accession numbers for
COI (hereafter abbreviated as acc. no. or acc. nos.) are listed
in Table 2.
BLAST and IDS analysis
Specimen COI sequences were compared to those within
the NCBI (GenBank) and BOLD (The Barcode of Life Data-
base) databases using NCBI nucleotide BLAST (Basic Local
Alignment Search Tool) (Altschul et al. 1990) and BOLD IDS
(Identifi cation System) (Ratnasingham and Hebert 2007),
which report percent similarity or identity scores. GenBank
and BOLD databases do not simultaneously share COI
sequence data, so search results of both databases are reported
herein.
RESULTS
SLIME
As of September 2018, SLIME contributors have gener-
ated 9222 photo vouchers of 106 terrestrial gastropod species
from southern California, and approximately 1220 citizen
scientists have participated in the project. From 2016 –2018,
annual SLIME -associated bioblitzes hosted on iNaturalist (e.g.
www.inaturalist.org/projects/el-nino-snailblitz) have each
generated over 1100 observations of 45 –57 species, including
the fi rst U.S. record of L. cylindracea (iNat 2602677) and mul-
tiple fi rst records for iNaturalist including the native and
imperiled megomphicid gastropods, Glyptostoma newberryanum
(Binney, 1858) (e.g. iNat 5113615) and G. gabrielense Pilsbry,
1938 (e.g. iNat 10235785) (NatureServe 2017). Other com-
monly observed species by SLIME and SLIME bioblitz con-
tributors between 2015–2018 are Cochlicopa lubrica (Müller,
1774), Cornu aspersum (Müller, 1774), Deroceras reticulatum
(Müller, 1774), Discus rotundatus (M ü l l e r , 1 7 7 4 ) , Helminthoglytpa
traskii (Newcomb, 18 61), Limacus fl avus Linnae us, 1758 , Milax
gagates (Draparnaud, 1801), Otala lactea (Müller, 1774),
Oxychilus draparnaudi (Beck, 1837), Paralaoma servilis
(Shuttleworth, 1852), Theba pisana (Müller, 1774), Vallonia
spp. Risso, 1826, and Zonitoides arboreus (Say, 1816) (Stearns
1900, Hanna 1966, Roth and Sadeghian 2006). Approximately
450 specimen lots have been collected as a result of SLIME,
which has increased the NHMLA terrestrial gastropod collec-
tion by 200% for terrestrial slugs and 5% overall.
Arion hortensis Férussac, 1819 (Fig. 1A, Fig. 2, Table 2)
First record in Los Angeles County, California. The fi rst
record of A. hortensis in Los Angeles County (iNat 2353797),
known to the authors, was made on 1 November 2015 in the
city of Monterey Park by C. Lee, a University of California,
Los Angeles (UCLA) undergraduate at the time and a prolifi c
iNaturalist user. Subsequently, slugs were collected near this
locality and elsewhere in Los Angeles from 2016–2017 (e.g.
LACM 179179, LACM 179181).
Size and habitat. In a subsample of A. hortensis specimens
collected from the UCLA campus in 2017 (iNat 8712051, LACM
2017-8.4), average slug length was 16 mm in adults (N = 12,
SD ± 3.0) and 5.5 mm in juveniles (N = 2, SD ± 0.7). At this site,
Figure 1. Collection localities of NHMLA specimens (from 2015 –2017) of A. hortensis (white circle), C. barbara (diamond), L. cylindracea
(triangle), P. albilabris (square), and X. conspurcata (black dot) in three counties of southern California. Shades of gray indicate the degree of
anthropogenic alteration of the land or “human footprint” of Woolmer et al. (2008), which incorporates urban development, human popula-
tion density, and freeways (shown as thin white lines).
SNAILS DOCUMENTED BY CITIZEN SCIENCE 237
once A. hortensis was located, a 45 -minute search revealed 15
individuals in leaf litter and landscaped areas adjacent to aca-
demic buildings. Cochlicopa lubrica (Müller, 1774), D. rotunda-
tus, P. servilis, and D. reticulatum were also found at this site.
Sequence data. NCBI nucleotide BLAST analysis of COI
sequences from eight Los Angeles County-collected speci-
mens (acc. no. MG190382–86, MG190388, MG19090, LACM
179162–64, 179178–81) returned a 99–100% identity score with
A. hortensis, including one specimen collected in Kentucky
(acc. no. EU382742, Mc Donnell et al. 2008) and 11 unpub-
lished sequences submitted by Dodd et al. (2003) and collected
in Wales (e.g. acc. nos. AY423681, AY423688) (Symondson,
pers. comm.). BOLD IDS analysis returned similar results.
Cochlicella barbara (Linnaeus, 1758) (Fig. 1B, Fig. 3, Table 2)
First record in Los Angeles and Orange counties, California.
The fi rst record of C. barbara in Los Angeles County, known to
the authors, was made on 1 February 2016 (LACM 180085) in
the backyard of a home in the Mt. Washington neighborhood
of Los Angeles wherein multiple individuals were observed
and collected by homeowners, E. and G. Han. Subsequent
observations were made by contributors to SLIME on
iNaturalist at this locality (e.g. iNat 2903166, 2993738), and
by S. Nakata (iNat 10177037) and I. Hayden (iNat 9852531)
elsewhere in Los Angeles County in 2015 and 2016. The fi rst
record of this species in Orange County was made on 11
November 2015 by S. Nakata from empty shells collected
in Laguna Hills (LACM 180088). Species observations con-
tributed to SLIME on iNatualist also confi rm that C. barbara
remains established in San Diego County (e.g. iNat 9444317,
5656914) (Roth and Hertz 1997).
Size and habitat. In a
subsample of C. barbara
specimens both live and
dead-collected in Los
Angeles (LACM 179412)
and Orange County (LACM
180085, 180088, 180089)
average adult shell length
was 8.6 mm (N = 8, SD ±
1.4) and width was 5.2 mm
(N = 8, SD ± 0.45). At the
Mt. Washington locality,
land snails H. traskii, X. con-
spurcata, and O. draparn-
audi were also found.
Sequence data. NCBI
nucleotide BLAST analysis
of one COI sequence from a
Los Angeles -collected speci-
men (acc. no. MG195978,
LACM 179412) returned a
98% identity score with C. conoidea collected in Portugal
(acc. no. KY818425, Neiber et al. 2017), the only other COI
sequence identifi ed as Cochlicella in GenBank. BOLD IDS
analysis returned an approximately 98% similarity score
for C. barbara with unavailable “Early-Release” sequence
accession numbers and locality data.
Lauria cylindracea (Da Costa, 1778) (Fig. 1C, Fig. 4, Table 2)
First record in the United States and Los Angeles County,
California. The fi rst record of L. cylindracea in the U.S.A.,
known to the authors, was made by C. Lee on 20 January
2016 on the UCLA campus (iNat 2602677, LACM 179780).
Subsequent observations and collection of L. cylindracea at
and near this site, including adults and juveniles, contin-
ued into 2017 (e.g. iNat 3862135, LACM 180086). Lauria cyl-
indracea has not been reported from beyond the UCLA
campus.
Size and habitat. The average shell length of a subsample of
live-collected L. cylindracea specimens from the UCLA campus
in 2016 (LACM 180087) was 3.8 mm in adults (N = 8, SD ±
0.27) and 2.2 mm in juveniles (N = 5, SD ± 0.19). At UCLA, L.
cylindracea was most commonly found between the sidewalk
edge and a regularly watered area with sycamore (Platanus sp.)
leaf litter and native and non-native shrubs. Other co-occuring
terrestrial gastropods were A. hortensis, O. draparnaudi, D.
rotundatus, P. servilis, Vallonia spp., and Z. arboreus.
Sequence data. NCBI nucleotide BLAST analysis of two
COI sequences from specimens collected in Los Angeles
(acc. nos. KX756234 and MG813887, LACM 179780, LACM
2017 –8.1) returned a 96% identity score with an unpublished
L. cylindracea sequence submitted by Pokryszko et al. (2014)
Figure 2. Observations and/or collected specimens of A. hortensis from the city of Los Angeles, Los Angeles
Co., California, by C. Lee. A–B. from landscaping along Sunset Blvd. between S. Bentley Ave. and Green-
feld Ave., 10 March 2016, LACM 179179. C–D. from the UCLA campus, 8 November 2016, iNat 4554285,
LACM 180322.
238 AMERICAN MALACOLOGICAL BULLETIN 36
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from a specimen collected on the island of Madeira (acc. no.
KJ452759) (Cameron, pers. comm.). BOLD IDS analysis
returned a 100% similarity score for L. cylindracea with
unavailable “Early-Release” sequence accession numbers and
locality data.
Pupoides albilabris (C.B. Adams, 1841) (Fig. 1D,
Fig. 5, Table 2)
First record in Riverside County, California. The only
record of P. albilabris in California since 1963 and the fi rst in
Riverside County, known to the authors, was made on 20
February 2017 in Cathedral City (LACM 179582) in the lawn
grass outside the residence of P. LaFollette, an NHMLA
Malacology museum associate. Notably, without the attention
and expertise of co-author
C. Lee and curation empha-
sis on terrestrial gastropods
because of SLIME, this spe-
cies would have remained
erroneously identified as
L. cylindracea, with which
it shares a pupiform shape
and small size (<4 mm).
Size and habitat. In a
subsample of P. albilabris
collected from the Cathedral
City locality (LACM 179582),
average shell diameter was
3.54 mm in adults (N = 12,
SD ± 0.39) with no juveniles
collected. Co-occuring gas-
tropods include Gastrocopta
pellucida hordeacella (Pilsbry,
1890), Hawaiia minuscula
(Binney, 1840), Polygyra
cereolus (Mühlfeld, 1816),
Rumina decollata (Linneaus,
1758), Vallonia excentrica
Sterki, 1893, Vallonia pul-
chella (Müller, 1774), and
Vitrea contracta (Westerlund,
1871).
Sequence data. BOLD
IDS analysis of two COI
sequences from two speci-
mens collected in Cathedral
City (acc. nos. MG813888
and MG813889, LACM
179582) returned a 91.09%
similarity score for P.
albilabris collected in
Ontario, Canada in 2015
(FTMWO150-16.COI-5P, FTMWO149-16.COI-5P). NCBI
nucleotide BLAST analysis returned an <90% identity score
with Vertigo ovata Say, 1822 (acc. no. JN941067, Nekola et al.
2012) and Partula similaris Hartman, 1886 (acc. no.
HQ230001, Ó Foighil et al. 2011), which have the most simi-
lar COI sequence to P. albilabris currently within GenBank.
Xerotricha conspurcata (Draparnaud, 1801) (Fig. 1E, Fig. 6,
Table 2)
First record in Los Angeles County, California. The fi rst
record of X. conspurcata in Los Angeles County (LACM
178850), known to the authors, was made on 10 August 2015
in Pasadena by C. McNassor, NHMLA’s former archivist and
regular contributor of land snail specimens to the NHMLA
Figure 3. Observations and/or collected specimens of C. barbara from Los Angeles, Orange, and San Diego
counties, California. A. from Camp Pendleton North, San Diego Co., 10 January 2018 by A. Bairstow, iNat
9444317. B. from a residential backyard, Mt. Washington, Los Angeles Co., 7 May 2016 by E. Han, iNat
3119173. C. from lot beside residential backyard, Mira Mesa, San Diego Co., 29 March 2017 by B. J. Lloyd,
iNat 5498858. D. from landscaping along a restaurant perimeter in Laguna Hills, Orange Co., 11 November
2015 by S. Nakata, LACM 180088.
SNAILS DOCUMENTED BY CITIZEN SCIENCE 239
Malacology collection. The fi rst record of X. conspurcata sub-
mitted to SLIME on iNaturalist was made on 23 January 2016
by E. and G. Han (iNat 2616486, LACM 180400) from the
yard and external walls of their Los Angeles home. Subsequent
observations of X. conspurcata were made at various sites in
Los Angeles County into 2017, including on the Glendale
Community College campus (iNat 4936439, LACM 179351)
and in a residential neighborhood in the city of Monrovia
(LACM 179779).
Size and habitat. In a subsample of X. conspurcata col-
lected from 3 sites in Los Angeles County (LACM 178921,
180083, 180400), average shell diameter was 5.46 mm in
adults (N = 16, SD ± 0.49) and 3.7 mm in juveniles (N = 5, SD
± 0.27). At the Han residence and Glendale Community
College campus, once X. conspurcata was found, a 10-minute
search revealed 10–15 live snails or empty shells. Living snails
were found in landscaped and un-maintained habitat, among
native and non-native vegetation, and on rocks and struc-
tures. At the Han residence, co-occurring gastropods included
H. traskii, C. barbara, C. lubrica, O. draparnaudi, and P. servilis.
Live X. conspurcata were more often found on vertical surfaces
(e.g. building walls) than on foliage or in leaf litter, which
likely explains the inadvertent collection of three X. conspurcata
individuals in a Malaise
trap at the Lascano family’s
BioSCAN site in Rosemead,
California. In the lab, seven
live-collected X. conspurcata
estivated for two months in
the absence of moisture,
and six resumed crawling
and feeding within 10 min-
utes of soaking their sub-
strate in water. The length
of this estivation period is
consistent with the fi ndings
of Arad et al. (1998).
Sequence data. NCBI
nucleotide BLAST analysis
of COI sequences from six
Los Angeles -collected spec-
imens (acc. nos. KX577716-
17, MG813890-93, LACM
179032, 179351 –52, 179606,
179779, 180400) returned
a 98 –100% identity score
with X. conspurcata from
Tunisia (acc. no. KU234584,
Hausdorf and Boessneck
2016) and Helicigona lapi-
cida (Linnaeus, 1758) col-
lected in Germany (acc. no.
AY546280, Steinke et al. 2014). This latter record was also
returned by BOLD IDS sequence analysis. COI sequences
from Los Angeles-collected specimens (e.g. KX577716-17)
confi rm the suggestion of Groenenberg et al. (2011) that the
COI sequence identified as H. lapicida by Steinke et al.
(2014) (acc. no. AY546280) in GenBank, is actually from
X. conspurcata.
DISCUSSION
For NHMs, citizen science that engages the public may
facilitate the growth of collections and improve the scope and
thoroughness of taxonomic inventories. The SLIME project
at NHMLA was designed to engage the public and has facili-
tated the discovery of fi ve introduced terrestrial gastropod
species in the California counties of Los Angeles, Orange, and
Riverside. It is also one of few on-going citizen science proj-
ects focused on terrestrial gastropods and may be the fi rst to
generate county, state, and country fi rst occurrence records
of these taxa from a large metropolitan area in North America.
Indices of biodiversity within urban environments rarely
focus on terrestrial gastropods although these taxa may be
Figure 4. Observations and/or collected specimens of L. cylindracea from the UCLA campus, Los Angeles
Co., California by C. Lee. A. near Election Walk, 20 January 2016, iNat 2602677, LACM 179780. B–E. in
Portolo Plaza, 11 August 2016, iNat 3862135, LACM 180087. C –E. showing angular denticle (C, D) and
granular micro-protuberances (E).
240 AMERICAN MALACOLOGICAL BULLETIN 36
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easy to fi nd, photograph, and collect. Likewise, evolutionary
responses of land snails to urbanization (e.g. reduced gene
fl ow, population fragmentation, adaptation, genetic drift) are
largely unstudied (Johnson and Munshi-South 2017), though
such research has focused on damselfl ies (Sato et al. 2008),
mice (Munshi-South and Kharchenko 2010), bobcats (Serieys
et al. 2015), and birds (Charmantier et al. 2017). While none of
the fi ve species documented here by SLIME has become the
subject of urban ecology research, citizen scientists’ species
observations could enable innovative studies on population
admixture, responses to habitat fragmentation, and urban-
associated life history changes.
Four of the fi ve species discovered in southern California
as a result of SLIME (A. hortensis, C. barbara, L. cylindracea,
X. conspurcata) were documented on multiple occasions at
discontinuous sites in populations with juveniles or sub-adults,
an indication that these species are breeding and are likely
established. Additional species introduction and/or popula-
tion range expansion may be facilitated by domestic and
international trade (e.g. tile, plants), access to water on resi-
dential property and parks, and available calcium carbonate
from building tile and stucco (Bergey et al. 2014). Non-native
terrestrial gastropod taxa to anticipate in southern California
include the “traveling species” of Smith (1989) and Robinson
(1999), and in particular, those that currently thrive in
Mediterranean climates. For example, Microxeromagna lowei
(Potiez and Michaud, 1838) and Eobania vermiculata (Müller,
1774) are not known in California at present, but have become
established in Australia (Blacket et al. 2016) and South Africa
(Herbert 2010). Were these species, or others, to be intro-
duced into southern California, it may be citizen scientists
who fi nd them fi rst (Stoeckle 2003).
The morphology, taxonomy, and worldwide distribution
(Fig. 7) of the fi ve species discovered in southern California
as a result of SLIME are discussed below.
Arion hortensis Férussac, 1819 (Fig. 7A)
Arion hortensis, or A. (Kobeltia) hortensis, is a small blue -
gray, black, or brown slug of 15 mm to rarely 50 mm in length
at maturity with no keel and a distinctly yellow-orange foot
sole that produces sticky mucus of the same color(s) (De
Winter 1984, Mc Donnell et al. 2009, Rowson et al. 2014b).
Its native range could be western Europe, but where it is truly
endemic may be obscured by numerous introductions
throughout the region and misidentifi cations with Arion dis-
tinctus Mabille, 1868 and Arion owenii Davies, 1979 (Davies
1977, 1979, Iglesias and Speiser 2001, Mc Donnell et al. 2008,
Rowson et al. 2014a, Hatteland et al. 2015). Outside of
Europe, A. hortensis is synanthropic in New Zealand (Barker
1999), Tasmania (Chichester and Getz 1973), South Africa
(Herbert and Kilburn 2004, Herbert 2010), and India
(Swapna and Reddy 2017), although in the latter three locali-
ties slug identity may not have been confi rmed by analysis of
DNA or reproductive morphology.
In North America, A. hortensis has been recorded in
Canada and throughout the eastern U.S.A. (Chichester and
Getz 1973, McCracken and Selander 1980, Pearce and Bayne
2003), the Great Lakes region (Grimm et al. 2009, Steury and
Pearce 2014), Kentucky (Mc Donnell et al. 2008), the Pacifi c
Northwest, and California (Quick 1952, Severns 2005, Roth
and Sadeghian 2006, Mc Donnell et al. 2009). Arion hortensis,
or a member of its species complex, has been intercepted in
U.S. agricultural and horticultural imports since at least the
1970s (Girard 1971) and, where pestiferous, A. hortensis has
damaged sunfl ower, vegetable, and grain crops (Barker 1999,
Iglesias and Speiser 2001, Mc Donnell et al. 2009, Thomas
et al. 2010).
Cochlicella barbara (Linnaeus, 1758) (Fig. 7B)
Cochlicella barbara is a small, xerophilic to mesophilic
snail, with a tiny umbilicus and a white /yellow to light
brown conical shell of 6–8 slightly convex whorls at maturity
(6.5–11 mm in height, 4 –6 mm in width) (Welter-Schultes
2012). Its native range spans southern Europe and the
Mediterranean region, but it has been introduced to the
United Kingdom (Cameron and Killeen 2001, Anderson 2005),
Japan (Habe 1980), Israel (Roll et al. 2009), Malta (Mifsud
et al. 2003), Santa Maria in the Azores (Cameron et al. 2012),
Bermuda (Bieler and Slapcinsky 2000), Madeira (Cook et al.
1993), South Africa (Quick 1952 as Cochlicella ?ventrosa,
Figure 5. Collected specimens of P. albilabris from Riverside Co.,
California by P. LaFollette. A–B. from a residential lawn in Cathe-
dral City, 20 February 2017, LACM 179582.
SNAILS DOCUMENTED BY CITIZEN SCIENCE 241
Herbert 2010) where it is considered invasive, New Zealand
(Barker 1999), Tasmania (DAFWA 2018), and mainland
Australia (Micic et al. 2013), where it is an agricultural pest of
cereal grain (Baker 1986). In parts of southern Europe where
C. barbara is native, it lives among ruins, stone walls, and in
city parks (Alexandrowicz 2012, Barbato et al. 2017).
In North America, C. barbara appears to be established
only in California, although two previous treatments of
introduced and pestiferous terrestrial gastropods did not
consider it to be established anywhere in the U.S. (i.e. Cowie
et al. 2009, LaBonte 2009). In 1900, C. barbara was docu-
mented in residential gardens of Oakland in Alameda County,
California (Stearns 1900) and, by the late 2000s it had been
reported in Santa Barbara, Santa Clara, Santa Cruz, San
Diego, and San Luis Obispo counties (Hanna 1966, Roth and
Hertz 1997, Leathers 2015). In 1939, Pilsbry made reference
to C. barbara as occurring
in South Carolina (as
Cochlicella ventrosa) based
on the published observa-
tion of Mazyck (1896), but
there are no records of C.
barbara or its synonyms in
subsequent terrestrial gas-
tropod species lists from
that region (e.g. Hubricht
1971). Notably, C. barbara
has been intercepted in
and on cargo and vehicles
in South Carolina, North
Carolina, New York,
Massachusetts, and Texas,
but records of it becoming
established in these regions
are lacking (Mumford 1965,
Adams et al. 1990). At U.S.
ports including Hawaii,
C. barbara snails have been
intercepted 608 times
between 1985 and 2009 in
agricultural and horticul-
tural cargo from Australia,
north Africa, and southern
Europe (Girard 1971,
Michalak and Price 2010).
The pest potential of C.
barbara to grain crops in
the U.S. has been recognized
by Cowie et al. (2009), the
California Department of
Food and Agriculture
(CDFA) (Leathers 2015),
and the Cooperative Agricultural Pest Survey (CAPS) pro-
gram (CAPS Priority Pest List 2019).
Lauria cylindracea (Da Costa, 1778) (Fig. 7C)
Lauria cylindracea is very small, mesophilic snail with an
ovoid, medium brown shell of 5–7 moderately convex whorls
at maturity (3.5–4.2 mm in height, 2 mm in width). The shell’s
apertural lip is refl ected, slightly thickened, and often bears a
single short, angular denticle (Pilsbry and Haas 1922, Grimm
et al. 2009, Herbert 2010) covered by granular micro-
protuberances. Its native range is circum-Mediterranean and
includes Israel (Mienis 2008), the northern border of the Black
Sea (Forsyth 1999, Kantor et al. 2009), and continental western
Europe (Welter-Schultes 2012). Lauria cylindracea has been
introduced to the United Kingdom and Ireland (Kerney 1976,
Wade et al. 2006), islands of the Caribbean and Atlantic (Preece
Figure 6. Observations and/or collected specimens of X. conspurcata from the city of Los Angeles, Los An-
geles Co., California. A–B. from Arroyo Seco Museum Science Magnet campus in Highland Park, 16 March
2016 by D. Escobar and I. Sanchez, LACM 179352. B. showing periostracal hairs. C. from a residential back-
yard, Mt. Washington, 7 May 2016 by E. Han, iNat 3119164. D. from El Sereno neighborhood, 4 February
2017 by C. Lee, iNat 5056156.
242 AMERICAN MALACOLOGICAL BULLETIN 36
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2001, Rosenberg and Muratov 2006), Réunion (Probst 2001),
New Zealand (Willan 1977, Barker 1999), and South Africa,
where it is considered invasive (Quick 1952, Herbert 2010). It
lives on stone and grass, in crevices of concrete, in gardens and
garden waste, and among leaf litter (Pilsbry and Haas 1922,
Kerney and Cameron 1979, Heller et al. 1997, Georgiev and
Stoycheva 2010, Herbert 2010, Welter-Schultes 2012). As a
small ground-dwelling detritivore it is not always pestiferous
where introduced (Naranjo-García and Castillo-Rodríguez 2017).
The fi rst published observation of L. cylindracea in North
America was made in 1988 by G. Holm from his residential
garden in Richmond, British Columbia, Canada (Holm
1988). Holm hypothesized that L. cylindracea snails were acci-
dently introduced there with a perennial fl owering plant
Anemone nemorosa Linnaeus planted years earlier and
brought from Denmark, where L. cylindracea is native
(Kerney and Cameron 1979). Holm (1988) reports that cut-
tings of this plant, possibly containing live L. cylindracea,
were given to friends to establish in their gardens, poten-
tially expanding the range of L. cylindracea in the region.
Since the late 1980s, L. cylindracea has been reported as
common in the leaf litter of urban parks in the Canadian cit-
ies of Vancouver and Victoria and their suburbs, the Gulf
Islands in the Canadian Strait of Georgia, and as far as 85 km
east of Vancouver into the Fraser Valley (Holm 1994, Forsyth
1999, Holm 2010, Forsyth and Williston 2012).
Pupoides albilabris (C.B. Adams, 1841) (Fig. 7D)
Pupoides albilabris is a small, xerophilic to mesophilic
snail, with a tapering pupiform shell of medium brown color
and 5–6.5 strongly convex whorls at maturity (3–5 mm in
height, 2 mm in width) (Pilsbry 1948, Fitch and Lokke 1956).
Its native range spans North America from Ontario, Canada,
south to Florida, across the American Midwest and Southwest
to northern Mexico (Pilsbry 1948, Theler et al. 2004, Nekola
and Coles 2010). It is not native to California (Pilsbry 1948).
Pupoides albilabris may be abundant in grasslands and
anthropogenically-altered environments such as fallow crop
fi elds, abandoned mining sites, and railroad tracks (Nekola
and Coles 2010, Arruda 2014). It has been reported in Cuba,
Hispaniola, Puerto Rico, and Bermuda, although at some of
these localities it has not been found since initially reported
(Pilsbry 1948, Bieler and Slapcinsky 2000). The only published
record of P. albilabris as introduced in continental North
America is of specimens found in California. Hanna (1966)
reported its discovery on a lawn of vegetative ground cover in
Brawley, Imperial County, California in 1963. Since then there
have been no published reports of this species in the state.
Xerotricha conspurcata (Draparnaud, 1801) (Fig. 7E)
Xerotricha conspurcata is a small, xerophilic snail with a
light to dark brown lenticular shell of 4–6 whorls at maturity
(5–6 mm in diameter) and numerous tiny periostracal
hairs, especially in sub-adults. Its modern range is circum-
Mediterranean, but this distribution may be a consequence of
accidental human introduction during antiquity from its
native range on the Iberian Peninsula (Welter-Schultes 2008).
Human-facilitated introduction of X. conspurcata continues
today from western Europe in exported produce (Herbert
2010, Vaisman and Mienis 2012), tile, and seeds (Robinson
1999). At U.S. ports including Hawaii, X. conspurcata indi-
viduals were intercepted 4,425 times between 1985 and 2009
in cargo from 31 countries including Italy, Spain, France,
Greece, Turkey, and Israel (Michalak and Price 2010). In
Figure 7. Known global distribution of fi ve terrestrial gastropod species found in southern California, based on GBIF data that include iNatu-
ralist observations (GBIF 2018). Additional localities mentioned in text are marked by an asterisk (*). A. A. hortensis. B. C. barbara. C. L.
cylindracea. D. P. albilabris. E. X. conspurcata.
SNAILS DOCUMENTED BY CITIZEN SCIENCE 243
regions of Greece and Italy with climate similar to that of
southern California, X. conspurcata is widespread and synan-
thropic, living in disturbed lots and parks (Georgiev and
Stoycheva 2010, Barbato et al. 2017). In Rome, X. conspurcata
is one of the most common snails living among ruins of the
Roman Forum and Colosseum (Alexandrowicz 2012).
The only reported populations of X. conspurcata in North
America are from California. The California Academy of
Sciences invertebrate zoology collection houses specimens
that were collected in 1996 from Contra Costa County during
a CDFA inspection of imported slate (Gill 1996). This discov-
ery led to observations of live X. conspurcata snails where the
slate shipment had been distributed: San Mateo, Alameda,
and Sonoma counties (Gill 1996, Roth and Sadeghian 2006,
Cowie et al. 2009, Michalak and Price 2010). In 2015, CDFA
did not consider X. conspurcata to be established in California,
and rated its pest potential as “B”, denoting a high dispersal
ability but low potential for agricultural or environmental
impact (Leathers 2015).
ACKNOWLEDGEMENTS
The authors are grateful to NHMLA’s Lindsey Groves
and Maria Wong for specimen curation in Malacology, the
Community Science Program for promoting SLIME, Greg
Pauly and Chris Thacker in Herpetology and Ichthyology for
molecular laboratory space, Lisa Gonzalez in Entomology for
providing X. conspurcata from the Lascano family BioSCAN
site, Giar Ann Kung in Entomology for assistance with SEM
and Keyence microscopy, and the Urban Nature Research
Center (UNRC) for funding and helpful feedback on this
paper. We also thank Ms. Griffi th and her 2016 ASMSM 8th
grade class for surveying their school campus for snails and
slugs, the citizen scientists and iNaturalist users R. J. Adams,
J. Bailey, J. A. Caballero, C. Hayden, S. Hewitt, T. Lawson,
P. Liff-Grieff, D. Loarie, S. Loarie, T. Rahn, and J. Rycenga for
valuable species observations and identifi cations, and Patrick
Krug at California State University, Los Angeles for addition-
al laboratory space. We are also grateful to Barry Roth for
additional specimen identifi cations and Robert Cameron at
the University of Sheffi eld and William Symondson at Cardiff
University for providing locality data for unpublished
GenBank sequences. The comments and suggestions of Eliza-
beth Shea, Tim Pearce, Wallace Meyer, and two anonymous
reviewers greatly improved this manuscript. Importantly,
these fi rst occurrence records would not have been possible
without the effort and enthusiasm of the citizen science col-
laborators who participated in the SLIME project: thank you
for your diligent documentation of biodiversity. Finally, we
express our gratitude to Cathy McNassor, in memoriam, who
contributed terrestrial gastropod specimens to NHMLA’s
Malacology collection and was a dedicated staff member at
NHMLA and the La Brea Tar Pits and Museum for more than
thirty years.
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fi nal revisions received: 10 October 2018
