Hydrobioid gastropods of the western United States

1
Hydrobioid gastropods of the western United States

• Robert Hershler
• Dept. of Invertebrate Zoology
• National Museum of Natural History
• Smithsonian Institution
• Washington, D.C. 20013-7012
• Phone [phone]
• Email hershlerr_at_si.edu

2
Outline 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

3
Geographic and taxonomic scope
WA
MT
OR

• 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

ID
WY
UT
CO
NV
CA
AZ
NM
4
Diversity of the western hydrobioid fauna(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

5
Hydrobiid systematics

• 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

Hydrobiidae
Moitessieridae
Lithoglyphidae
Cochliopidae
Amnicolidae
COI-18S tree (Wilke et al., 2001)
6
Classification of the western hydrobioid genera

• Family Amnicolidae
• Amnicola
• Colligyrus
• Family Cochliopidae
• Eremopyrgus
• Ipnobius
• Littoridinops
• Tryonia
• Family Hydrobiidae
• Pyrgulopsis
• Family Lithoglyphidae
• Fluminicola
• Family incertae sedis
• Potamopyrgus
• Pristinicola
• Taylorconcha

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Early stage of taxonomic refinement

• 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

8
Construction 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

9
Methods

• 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

10
Examination 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

11
Examination of relevant female anatomy (oviduct
glands)
Ag
Cg

• Oviduct glands (albumen gland, Ag capsule gland,
  Cg) easily observed remove digestive gland and
  ovary (spire) if necessary

12
Examination of relevant female anatomy (bursa
copulatrix)
bursa copulatrix
Cg
Ag

• Cut along left side of mantle, pull tissue back
  (and remove stomach) to expose (left side of)
  oviduct glands and bursa copulatrix

13

• 1. Female oviduct glands well-developed .
  2
• Oviduct glands atrophied (functioning as brood
  chamber) .. 8

14

• 2. Penis simple 3
• Penis having lobes and/or glands 6

15

• 3. Bursa copulatrix absent Taylorconcha
  
• Bursa copulatrix present .. 4

seminal receptacle
seminal receptacle
bursa copulatrix
16
Taylorconcha 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

17
Taylorconcha

• Penis vermiform animal often very pale

18

• 4. Bursa copulatrix (and its duct) overlapping
  right side of albumen gland ......................
  ......................... Fluminicola
• Bursa copulatrix (and its duct) overlapping left
  side of albumen gland .. 5

bursal duct
albumen gland
bursa copulatrix
bursa copulatrix
19

• 4. Shell protoconch having spirally arranged
  sculpture ........... ............................
  ..........................................
  Fluminicola
• Protoconch surface wrinkled or pitted
  . 5

20
Fluminicola Carpenter, 1864

• 24 species
• Shell 2-12 mm tall globose to narrow conic
• Northwestern USA (and western Canada) springs,
  streams, rivers, lakes

21
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

22
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. nuttallianus
F. virens
23

• 5. Penis rectangular to elongate (lt4X longer than
  wide) ... .......................................
  ............ Pyrgulopsis (in part)
• Penis vermiform (gt6X longer than wide)
  ...................... ..........................
  .......................................
  Pristinicola

24

• 5. Penial duct narrow .......................
  Pyrgulopsis (in part)
• Penial duct wide ................................
  ........ Pristinicola

penial duct
penial duct
25

• 5. Operculum thin, amber-colored .....
  Pyrgulopsis (in part)
• Operculum thick, red .......
  Pristinicola

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Pristinicola 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

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• Penis having surficial glands .. Pyrgulopsis
  (in part)
• Penis having papillae ................
  Littoridinops
• Penis having an internal, tubular gland
  . 7

papillae
tubular gland
glandular field
glandular pad
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Pyrgulopsis 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

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Another taxonomically challenging genus
100
M1A
56
M1B
P. n. sp. 1
M3A
M4B
M5A
M5C
M5B
M3D
M4D
M3C
59
100
M4A
NDI tree (Liu et al., 2003)
M3B
M4C
M10A
91
M11A
M16A
M18A
57
M12A
M12B
M13B
66
M15A
M13D

• MtDNA phylogeny (to left) suggests that
  morphologically similar populations assigned to
  P. micrococcus represent multiple evolutionary
  lineages (indicated by arrows) and species
  requires revision

M13F
M14B
M13E
M13C
M17A
M22A
M27A
92
M28A
M24B
M24A
P. turbatrix
57
M19A
M20A
72
M21A
M30A
P. amargosae
100
P. crystalis
62
P. erythropoma
100
P. isolata
P. nanus
100
P. owensensis
P. perturbata
56
P. giulianii
63
P. stearnsiana - PC
P. stearnsiana - CC
P. stearnsiana - WC
P. wongi
P. californiensis
P. sterilis
P. greggi
M2A
97
M2B
M2C
M2D
86
M25A
65
M25C
99
M26A
96
M26C
M26B
P. n. sp. 2
55
P. deaconi
P. fausta
Marstonia
0.005 substitutions/site
30
Unsettled generic limits
cruciglans
kolobensis
81
variegata
bryantwalkeri
pictilis
inopinata
plicata

• Eastern North American genus Floridobia nested
  within Pyrgulopsis clade
• Genera are morphologically similar but differ in
  number of seminal receptacles (Sr)

lentiglans
sterilis
96
Nymphophilus minckleyi
Nymphophilus acarinatus
COI tree (Liu Hershler, 2005)
manantiali
pecosensis
carinifera
avernalis
merriami
bruneauensis
Floridobia
sublata
gibba
97
lata
breviloba
wongi
greggi
hubbsi
98
Floridobia floridana
Floridobia winkleyi
eremica
93
lockensis
villacampae
thermalis
saxatilis
peculiaris
Pyrgulopsis clade
sadai
davisi
gilae
deaconi
Pyrgulopsis
Floridobia
militaris
ventricosa
84
sulcata
61
neritella
landyei
trivialis
arizonae
archimedis
bernardina
75
erythropoma
fairbanksensis
turbatrix
77
diablensis
giulianii
stearnsiana
81
taylori
owensensis
californiensis
63
montana
anatina
pellita
bifurcata
micrococcus
Sr
dixensis
conica
simplex
Sr
84
glandulosa
sola
91
robusta1
robusta2
74
intermedia
97
Marstonia halcyon
100
Marstonia agarhecta
Marstonia hershleri
Cincinnatia integra
0.1
31
Littoridinops 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

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• 7. Shell 3.0-4.5 mm tall .................
  .. Amnicola
• Shell 1.3-3.3 mm tall .........................
  .... Colligyrus

1 mm
1 mm
33

• 7. Penial lobe medially positioned
  ..................... Amnicola
• Penial lobe basally positioned
  Colligyrus

penial lobe
penial lobe
penial lobe
34
Amnicola 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

35
Colligyrus 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

36

• 8. Males absent ..... 9
• Males present .. 10
• 9. Shell conical outer lip of aperture thickened
  internally ......................................
  ................... Potamopyrgus
• Shell turriform outer lip of aperture thin or
  only slightly thickened ..........................
  ................ Tryonia (in part)

37

• 9. Inner side of operculum having a white
  (calcareous) smear ..............................
  ................. Potamopyrgus
• Inner side of operculum without a white
  (calcareous) smear ...............................
  ................ Tryonia (in part)

38
Potamopyrgus 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

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• 10. Penis without lobes ..................
  Potamopyrgus
• Penis having lobe(s) . 11

penial lobe
40

• 11. Penial lobes cuboidal .......................
  ........... Eremopyrgus
• Penis having papilla(e) ... 12

41
Eremopyrgus Hershler et al., 1999

• One western species (E. eganensis)
• Shell 3.1-3.8 mm tall conical
• North-central Great Basin (Steptoe Valley)
  springs

42

• 12. Single papilla present on penis
  ............ Ipnobius
• Two to six papillae present on penis ....
  Tryonia (in part)

43
Ipnobius Hershler, 2001

• Monotypic (I. robustus)
• Shell 1.1-2.2 mm tall, ovate-conic or conical
• Southwestern Great Basin (Death Valley) thermal
  springs

44
Tryonia 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

45
Estuarine Tryonia

• T. imitator widespread (historically), native
• T. porrecta ( T. protea) San Francisco Bay,
  cryptogenic