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