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Hydrobioid gastropods of the Hydrobioid gastropods of the western United Stateswestern United States
Robert HershlerDept. of Invertebrate ZoologyNational Museum of Natural HistorySmithsonian InstitutionWashington, D.C. 20013-7012Phone (202) 633-1747Email hershlerr@si.edu
Outline of presentationOutline of presentation
• Introduction – relevant background information (scope, systematics, methods)
• Work through a newly prepared taxonomic key to the hydrobioid genera of the western USA (including treatment of the NZMS)
• Briefly review each genus
Geographic and Geographic and taxonomic taxonomic
scopescope
CA
NV
AZ
UT
OR
ID
WA
NM
CO
WY
MT
• Restricted to the portion of the United States that is west of the continental divide
• Restricted to the family Hydrobiidae as traditionally constituted
• Only formally described and currently recognized species are considered
Diversity of the western hydrobioid faunaDiversity of the western hydrobioid fauna(number of western species in parentheses)(number of western species in parentheses)
Amnicola (1)Colligyrus (3)Eremopyrgus (1)Fluminicola (24)Ipnobius (1)*Littoridinops (1)*Potamopyrgus (1)Pristinicola (1)Pyrgulopsis (112)Taylorconcha (2)Tryonia (13)
Total: 11 genera, 160 species (158 native)
* Introduced to western United States
Hydrobiid Hydrobiid systematicssystematics• Several
traditionally recognized hydrobiid subfamilies are now treated as separate family units (Bouchet & Rocroi, 2005) based on molecular phylogenetic evidence (Wilke et al., 2000, 2001)
• The term “hydrobioid” (sensu Davis, 1979) is used for this taxonomic assemblage
COI-18S tree(Wilke et al., 2001)
Hydro
biid
ae
MoitessieridaeLithoglyphidae
Cochliopidae
Amnicolidae
Classification of the western hydrobioid Classification of the western hydrobioid generagenera
Family AmnicolidaeAmnicolaColligyrus
Family CochliopidaeEremopyrgusIpnobiusLittoridinopsTryonia
Family HydrobiidaePyrgulopsis
Family LithoglyphidaeFluminicola
Family incertae sedisPotamopyrgusPristinicolaTaylorconcha
0 1 5 10 18 22 27 29
138158
0
50
100
150
200
1800 1850 1900 1950 2000
Cumulative number of western hydrobioid species described since 1800
Early stage of taxonomic Early stage of taxonomic refinementrefinement
• Most species recently described and little studied• Actual species diversity likely to be much larger than
currently recognized• Generic classification has been in flux for the past few
decades and is still somewhat unsettled
Construction of taxonomic keyConstruction of taxonomic key• Cannot construct key solely based
on shells because western hydrobioid genera are principally differentiated by anatomical characters
• To aid user, key only employs characters that can be readily observed using a dissecting microscope (i.e., no detailed dissections of micro-anatomy, no need to use SEM)
• Several genera and several characters appear twice in the key (consequence of variation within genera)
• Key works best if multiple specimens are in hand
MethodsMethods• Relax snails with menthol prior to fixation (preferred) or
simply place them into concentrated ethanol• Clean shells with Clorox; remove shell (from animal) with
concentrated hydrochloric acid• Dissection tools – fine forceps, iridectomy scissors, insect pins
Examination of relevant male anatomyExamination of relevant male anatomy
• Cut through or pull back mantle edge to expose entire penis• Examine both upper (dorsal) and lower (sides) of penis for
glands
Examination of relevant female Examination of relevant female anatomy (oviduct glands)anatomy (oviduct glands)
• Oviduct glands (albumen gland, Ag; capsule gland, Cg) easily observed; remove digestive gland and ovary (spire) if necessary
Ag Cg
Examination of relevant female Examination of relevant female anatomy (bursa copulatrix)anatomy (bursa copulatrix)
• Cut along left side of mantle, pull tissue back (and remove stomach) to expose (left side of) oviduct glands and bursa copulatrix
bursacopulatrix
AgCg
1. Female oviduct glands well-developed .…………………… 2Oviduct glands atrophied (functioning as brood chamber) ……………………………..……………………………… 8
2. Penis simple ……………………………………………………………… 3Penis having lobes and/or glands ………………………………… 6
3. Bursa copulatrix absent ……………………………TaylorconchaBursa copulatrix present ………………………………………….. 4
seminal receptacleseminal receptaclebursa copulatrixbursa copulatrix
seminal receptacleseminal receptacle
TaylorconchaTaylorconcha Hershler et al., 1994 Hershler et al., 1994
• Two species• Shell 2-4 mm tall;
globose to ovate-conic
• Middle-lower Snake River basin; rivers and their tributary springs
TaylorconchaTaylorconcha
• Penis vermiform; animal often very pale
4. Bursa copulatrix (and its duct) overlapping right side of albumen gland ............................................... FluminicolaBursa copulatrix (and its duct) overlapping left side of albumen gland ………………………………………………………….. 5
bursa copulatrix
albumen gland
bursa copulatrix
bursal duct
4. Shell protoconch having spirally arranged sculpture ........... ...................................................................... FluminicolaProtoconch surface wrinkled or pitted …………………………. 5
FluminicolaFluminicola Carpenter, 1864 Carpenter, 1864
• 24 species• Shell 2-12
mm tall; globose to narrow conic
• Northwestern USA (and western Canada); springs, streams, rivers, lakes
Tip of the iceberg?Tip of the iceberg?• 13 of 24 congeners
recently described from upper Sacramento River basin (Hershler et al., 2007)
• Combined morphology-molecular approach was needed to delineate species
• Results suggest that other Pacific Northwest drainages may also harbor a large number of undescribed species of Fluminicola
Fluminicola non-monophyly?Fluminicola non-monophyly?• Fluminicola virens is strongly divergent
(morphologically and genetically) relative to other congeners; genus is probably non-monophyletic
• The resulting taxonomic problem is unresolved because the type species of Fluminicola (F. nuttallianus) is little studied and probably extinct
F. virens F. nuttallianus
5. Penis rectangular to elongate (<4X longer than wide) ... ................................................... Pyrgulopsis (in part)Penis vermiform (>6X longer than wide) ...................... ................................................................. Pristinicola
5. Penial duct narrow ....................... Pyrgulopsis (in part)Penial duct wide ........................................ Pristinicola
penialduct
penialduct
5. Operculum thin, amber-colored ..... Pyrgulopsis (in part)Operculum thick, red ......…………………………. Pristinicola
PristinicolaPristinicola Hershler et al., 1994 Hershler et al., 1994
• Monotypic (P. hemphilli)
• Shell ca. 1.5-3.5 mm tall; pupoidal
• Lower Snake-Columbia River basin, northwest Great Basin, Pacific Coastal drainage in Washington; springs
6. Penis having surficial glands ……..…… Pyrgulopsis (in part)Penis having papillae …………………................ LittoridinopsPenis having an internal, tubular gland .……………………… 7
tubulargland
glandular field
glandularpad
papillae
PyrgulopsisPyrgulopsis Call & Pilsbry, 1886 Call & Pilsbry, 1886
• 112 western species• Shell 1-8 mm tall;
globose to turriform• Widely distributed in
western USA; springs, rivers, lakes
• Many additional congeners await description
10056
97
10059
57
57
72
91
86
9699
100
10062
55
5663
100
92
66
M1AM1B
P. n. sp. 1M3AM4BM5AM5CM5B
M3DM4DM3CM4AM3BM4C
M10AM11AM16A
M18AM12AM12B
M13BM15AM13DM13FM14BM13EM13CM17A
M22AM27A
M28AM24BM24A
P. turbatrixM19AM20AM21A
M30AP. amargosae
P. crystalisP. erythropoma
P. isolataP. nanus
P. owensensisP. perturbata
P. giulianiiP. stearnsiana - PC
P. stearnsiana - CCP. stearnsiana - WC
P. wongiP. californiensis
P. sterilisP. greggi
M2AM2BM2CM2D
M25AM25C
M26AM26CM26BP. n. sp. 2P. deaconi
P. faustaMarstonia
0.005 substitutions/site
65
Another Another taxonomicaltaxonomically ly challenging challenging genusgenus• MtDNA phylogeny
(to left) suggests that morphologically similar populations assigned to P. micrococcus represent multiple evolutionary lineages (indicated by arrows) and species requires revision
NDI tree(Liu et al., 2003)
• Eastern North American genus Floridobia nested within Pyrgulopsis clade
• Genera are morphologically similar but differ in number of seminal receptacles (Sr)
97100
81
93
8461
97
63
77
81
75
91
74
96
98
0.1
cruciglanskolobensis
variegatabryantwalkeripictilisinopinata
plicatalentiglans
sterilisNymphophilus minckleyi
Nymphophilus acarinatusmanantiali
pecosensiscarinifera
avernalismerriami
bruneauensissublata
gibbalata
brevilobawongi
greggihubbsi
Floridobia floridanaFloridobia winkleyi
eremicalockensis
villacampaethermalis
saxatilispeculiarissadai
davisigilae
deaconimilitaris
ventricosasulcataneritella
landyeitrivialis
arizonaearchimedisbernardina
erythropomafairbanksensis
turbatrixdiablensisgiulianii
stearnsianatayloriowensensis
californiensismontana
anatinapellita
bifurcatamicrococcus
dixensisconicasimplex
glandulosasolarobusta1robusta2
intermediaMarstonia halcyonMarstonia agarhecta
Marstonia hershleriCincinnatia integra
84
COI tree (Liu & Hershler, 2005)
Unsettled generic Unsettled generic limitslimits
Pyrgulopsisclade
Floridobia
Pyrgulopsis Floridobia
SrSr
LittoridinopsLittoridinops Pilsbry, 1952 Pilsbry, 1952
• One western species (L. monroensis), introduced; native to Atlantic coast of USA
• Shell up to 4.7 mm tall; conical
• San Francisco Bay; estuaries
7. Shell 3.0-4.5 mm tall ……………………................... AmnicolaShell 1.3-3.3 mm tall …….........................….…... Colligyrus
1 mm 1 mm
7. Penial lobe medially positioned ……..................... AmnicolaPenial lobe basally positioned ………………………… Colligyrus
penial lobe
peniallobe
peniallobe
AmnicolaAmnicola Gould & Haldeman, 1840 Gould & Haldeman, 1840
• One western species (A. limosus)
• Shell 3.0-4.5 mm tall, sub-globose to ovate-conic
• Northeast Great Basin, upper Columbia River basin (also widespread in eastern USA); lakes
ColligyrusColligyrus Hershler et al., 1999 Hershler et al., 1999
• Three species• Shell 1.3-3.3 mm
tall, globose to conical
• Northeastern and northwestern Great Basin, upper Snake and upper Sacramento River basins; springs
8. Males absent …………………………………………..…………... 9Males present …………………………………………………….. 10
9. Shell conical; outer lip of aperture thickened internally …......................................................... PotamopyrgusShell turriform; outer lip of aperture thin or only slightly thickened .......................................... Tryonia (in part)
9. Inner side of operculum having a white (calcareous) smear …............................................... PotamopyrgusInner side of operculum without a white (calcareous) smear ............................................... Tryonia (in part)
PotamopyrgusPotamopyrgus Stimpson, 1865 Stimpson, 1865• One western species
(P. antipodarum), introduced; native to New Zealand
• Shell up to 5 mm tall; conical
• Widely distributed in Snake-Columbia River basin, eastern Great basin; scattered occurrences in other western drainages; diverse habitats
10. Penis without lobes ……….................. PotamopyrgusPenis having lobe(s) ………………………………………. 11
peniallobe
11. Penial lobes cuboidal .................................. Eremopyrgus
Penis having papilla(e) …………………………………………... 12
EremopyrgusEremopyrgus Hershler et al., 1999 Hershler et al., 1999
• One western species (E. eganensis)
• Shell 3.1-3.8 mm tall; conical
• North-central Great Basin (Steptoe Valley); springs
12. Single papilla present on penis ....……………........ IpnobiusTwo to six papillae present on penis ..….. Tryonia (in part)
IpnobiusIpnobius Hershler, 2001 Hershler, 2001
• Monotypic (I. robustus)
• Shell 1.1-2.2 mm tall, ovate-conic or conical
• Southwestern Great Basin (Death Valley); thermal springs
TryoniaTryonia Stimpson, 1865 Stimpson, 1865
• 13 western species• Shell 1.2-7.5 mm
tall; ovate-conic to turriform
• Widely (but disjunctly) distributed in southwest USA; typically found in thermal springs
Estuarine Estuarine TryoniaTryonia• T. imitator;
widespread (historically), native
• T. porrecta (= T. protea); San Francisco Bay, cryptogenic