MUSSELpdb
Taxonomy
Species & Genus Richness of
freshwater mussels
by Taxonomy
Species & Genus Richness of
freshwater bivalves
by Family
Geography
Species Richness & Endemism of
freshwater mussels
by Geography
Data last updated
Sun 12 April 2026
Bivalvia | Unionida | Unionoidea | Unionidae | Ambleminae | Lampsilini
genus Medionidus Simpson, 1900: cladomics
6 Recent valid species (7 total species)
Cladomics pages are experimental — even more so than the rest of this site!
The purpose of the cladomics pages for each genus and family-group level taxon is to provide statistics and references indicating the extent to which published phylogenetic work supports the classification used here.
The Cladomics Summary provides an overview of the number of studies that have included terminal species representing this taxon as well as an indication of how frequently it has been recovered as monophyletic.
Following the summary, the available published clades representing the taxon are listed.
For more information, visit the Cladomics FARQ (frequently asked rhetorical questions) page. Abbreviations for the various statistics are explained on the FARQ!
Cladomics Summary
number of species = 6 (7 total)
analyzed in 20 cladograms in 13 publications
maximum number of terminals in an analysis = 3 (mean = 1.3, median = 1)
Basic Monophyly
number of cladograms that test basic monophyly (i.e., more than 1 included species) = 5
maximum number of included terminals = 3, (mean = 2.2 median = 2)
proportion of cladograms that support basic monophyly = 0
Pairwise Cladogram Clustering
The graphs below depict in two dimensions all pair-wise ingroup distances within the cladome. See the Cladmoics FARQ for more information.
Cladograms
Campbell & Lydeard, 2026 [Publ 4810], fig. 6-14
** Top Monophyly Cladogram ** ** Top Sister-Group Cladogram **
| tT | bi | riS | oT | roT | roS | iD | |
| 3 | 58 | 66 | 3 | 629 | 90 | 26 | 0 |
+-------- Potamilus_inflatus
+--------+
| | +----- Potamilus_ohiensis
| +--+
| | +-- Potamilus_amphichaenus
| +--+
+-----------------------------------+ +-- Potamilus_streckersoni
| |
| | +----- Potamilus_fragilis__2
| | +--------+
| | | | +-- Potamilus_leptodon
| | | +--+
| +--+ +-- Potamilus_fragilis__1
| |
| | +----------- Potamilus_metnecktayi
| | |
| +--+ +-------- Potamilus_alatus__3
| | |
| +--+ +----- Potamilus_alatus__2
--+ | |
| +--+----- Potamilus_purpuratus__2
| |
| | +-- Potamilus_alatus__1
| +--+
| +-- Potamilus_purpuratus__1
|
| +-- Villosa_villosa
| +-----------------------------------------------+
| | +-- Atlanticoncha
| |
| | +-- Cambarunio_nebulosus
| | +--------------------------------------------+
+--+ | +-- Ligumia
| |
| | +-------- Leaunio_umbrans
| | +-----------------------------------+
| | | | +----- Cambarunio_taeniatus
+--+ | +--+
| | | +-- Cambarunio_iris
| | +--+
| | +-- Cambarunio_simus
| |
| | +----------------------------------------- Hamiota
| | |
+--+ | +----------------------- Pachynaias
| | |
| | +--------------+ +-------------------- Sagittunio
| | | | |
| | | | | +----- Ellipsaria
| | | +--+ +-----------+
| | | | | | +-- Potamilus_capax
| | | | | +--+
| | | | | +-- Truncilla
+--+ | +--+
| | | +----- Medionidus_acutissimus **
| | | +--------+
| | | | | +-- Lemiox
| | | | +--+
| | +--+ +-- Medionidus_penicillatus **
| | |
| | | +----------- Ptychobranchus
| | | |
| | +--+ +-- Cyprogenia_aberti__2
| | | +-----+
+--+ | | +-- Dromus
| +--+
| | +----- Cyprogenia_stegaria__2
| +--+
| | +-- Cyprogenia_aberti__1
| +--+
| +-- Cyprogenia_stegaria__1
|
| +-- Villosa_delumbis
| +--------------------------------+
| | +-- Villosa_vibex
| |
| | +-------------- Obovaria_olivaria
| | |
| | +-----------------+ +-- Venustaconcha
| | | | +--------+
| | | | | +-- Epioblasma
| | | +--+
| | | | +-------- Obovaria_retusa
+--+ | +--+
| | | +----- Obovaria_choctawensis
| | +--+
| | | +-- Obovaria_unicolor
| | +--+
| | +-- Obovaria_subrotunda
| |
| | +-- Mesonaias
| | +-----------------------+
| | | +-- Obovaria_arkansasensis
| | |
+--+ +--+ +-- Lampsilis_splendida
| | | +--------------------+
| | | | +-- Lampsilis_bracteata
| | | |
| | +--+ +-- Lampsilis_fasciola
| | | +-----------------+
| | | | +-- Ortmanniana_pectorosa
| | +--+
| | | +----------------- Lampsilis_ornata
| | | |
| | +--+ +-------------- Lampsilis_ovata__2
| | | |
| | +--+ +----------- Lampsilis_dolabraeformis
| | | |
| | | | +----- Lampsilis_cardium__2
| | +--+ +--+
| | | | | +-- Lampsilis_cardium__1
+--+ | | +--+
| +--+ +-- Lampsilis_satura
| |
| | +----- Lampsilis_cariosa__2
| +--+
| | +-- Lampsilis_ovata__1
| +--+
| +-- Lampsilis_cariosa__1
|
| +----------- Ortmanniana_ligamentina__2
| +--------------+
| | | +-------- Lampsilis_abrupta
| | +--+
| | | +----- Lampsilis_higginsii__2
| | +--+
| | | +-- Ortmanniana_ligamentina__1
| | +--+
+--+ +-- Lampsilis_higginsii__1
|
| +----- Medionidus_conradicus **
| +-----------------+
| | | +-- Leaunio_lienosus
| | +--+
| | +-- Leaunio_vanuxemensis
| |
+--+ +-- Lampsilis_floridensis
| +-----------------+
| | +-- Lampsilis_teres
| |
| | +-- Lampsilis_siliquoidea__1
+--+ |
| +-- Lampsilis_siliquoidea__2
| +--------------+
| | +-- Lampsilis_powellii__1
| | |
+--+ +-- Lampsilis_powellii__2
|
| +-------------- Lampsilis_sietmani
| |
+--+ +-- Lampsilis_straminea__2
| +--------+
| | +-- Lampsilis_virescens
+--+
| +-------- Lampsilis_hydiana__2
+--+
| +----- Lampsilis_hydiana__1
+--+
| +-- Lampsilis_bergmanni
+--+
+-- Lampsilis_straminea__1
Campbell et al., 2005 [Publ 2660], fig. 2
| tT | bi | riS | oT | roT | roS | iD | |
| 2 | 6 | 0 | 2 | 100 | 41 | 22 | 65 |
+----- Obliquaria
+--------+
| | +-- Cyrtonaias
| +--+
| +-- Glebula
|
| +----------- Sagittunio
| |
| +----------- Leaunio
| |
| +----------- Potamilus
| |
| +----------- Hamiota
| |
| | +-- Ellipsaria
--+ +--------+
| | +-- Truncilla
| |
| | +----- Lampsilis_teres
| +-----+
| | | +-- Ortmanniana_ligamentina
| | +--+
| | +-- Lampsilis_siliquoidea
| |
| | +----- Villosa
| +-----+
| | | +-- Ligumia
| | +--+
| | +-- Cambarunio
| |
+--+ +-------- Ortmanniana_pectorosa
+--+
| | +----- Lampsilis_ornata
| +--+
| | +-- Lampsilis_cardium
| +--+
| +-- Lampsilis_ovata
|
| +-------- Obovaria_olivaria
| |
| +-------- Venustaconcha_ellipsiformis__2
+--+
| +-------- Epioblasma
| |
| | +----- Obovaria_unicolor
| +--+
| | +-- Obovaria_arkansasensis
| +--+
| +-- Obovaria_subrotunda
|
| +-- Ptychobranchus
| +-----+
| | +-- Venustaconcha_ellipsiformis__1
| |
+--+ +----- Medionidus_conradicus **
| |
| | +-- Lemiox
+--+--+
| +-- Medionidus_acutissimus **
|
| +-- Dromus
+--+
+-- Cyprogenia
Zanatta & Murphy, 2006 [Publ 2672], fig. 1
| tT | bi | riS | oT | roT | roS | iD | |
| 2 | 6 | 0 | 2 | 54 | 46 | 22 | 69 |
+-- Cyrtonaias
+--------------------------------+
| +-- Glebula
|
--+ +-------------------------------- Paetulunio
| |
| | +-- Obliquaria
+--+ +--------------------------+
| | +-- Toxolasma
| |
| | +-------------------------- Sagittunio
+--+ |
| | +----------- Potamilus
| | |
| | +-----------+ +-- Medionidus_conradicus **
| | | | +-----+
+--+ | | | +-- Ptychobranchus
| | +--+
| | | +----- Medionidus_acutissimus **
| | | |
| | +--+----- Lemiox
| | |
| | | +-- Dromus
+--+ +--+
| +-- Cyprogenia
|
| +----- Lampsilis_teres
| +--------------+
| | | +-- Truncilla
| | +--+
| | +-- Ellipsaria
| |
+--+ +----------------- Leaunio
| |
| | +----------- Hamiota
| | |
| | +--+ +-- Lampsilis_fasciola
+--+ | | +-----+
| | | | +-- Ortmanniana_pectorosa
| | +--+
| | | +----- Lampsilis_ornata
| | +--+
| | | +-- Lampsilis_ovata
+--+ +--+
| +-- Lampsilis_cardium
|
| +----- Venustaconcha
| +-----+
| | | +-- Obovaria
| | +--+
+--+ +-- Epioblasma
|
| +-------- Lampsilis_siliquoidea
+--+
| +----- Ortmanniana_ligamentina
+--+
| +-- Cambarunio
+--+
+-- Ligumia
Zanatta & Murphy, 2006 [Publ 2672], fig. 2
| tT | bi | riS | oT | roT | roS | iD | |
| 2 | 3 | 0 | 2 | 55 | 46 | 22 | 67 |
+-- Paetulunio
+-----------------------------------+
| +-- Toxolasma
|
| +----- Obliquaria
| +-----------------------------+
--+ | | +-- Glebula
| | +--+
| | +-- Cyrtonaias
| |
| | +----- Ptychobranchus
| | +--+
+--+ | | +-- Dromus
| | +--+
| +-----------------------+ +-- Cyprogenia
| | |
| | | +----- Medionidus_conradicus **
| | +--+
| | | +-- Medionidus_acutissimus **
| | +--+
+--+ +-- Lemiox
|
| +----------------------------- Sagittunio
| |
| +----------------------------- Potamilus
| |
| | +-- Truncilla
+--+ +-----------------------+
| | +-- Ellipsaria
| |
| | +-- Ortmanniana_pectorosa
| | +-----+
| | | +-- Lampsilis_fasciola
+--+ +--------------+
| | | +----- Lampsilis_ornata
| | +--+
| | | +-- Lampsilis_ovata
| | +--+
| | +-- Lampsilis_cardium
+--+
| +-- Ligumia
| +--+
| | +-- Cambarunio
| +--------------+
| | | +-- Lampsilis_teres
| | +--+
+--+ +-- Hamiota
|
| +----------------- Leaunio
| |
+--+ +-------------- Ortmanniana_ligamentina
| |
+--+ +----------- Lampsilis_siliquoidea
| |
+--+ +-------- Obovaria_olivaria
| |
| +-------- Venustaconcha
+--+
+-------- Epioblasma
|
| +----- Obovaria_unicolor
+--+
| +-- Obovaria_subrotunda
+--+
+-- Obovaria_arkansasensis
Campbell et al., 2005 [Publ 2660], fig. 1
| tT | bi | riS | oT | roT | roS | iD | |
| 2 | 9 | 0 | 2 | 100 | 41 | 22 | 71 |
+-------- Toxolasma
+--------------------+
| | +----- Obliquaria
| +--+
| | +-- Cyrtonaias
| +--+
| +-- Glebula
|
| +-------------- Potamilus
| |
| | +-------- Medionidus_acutissimus **
--+ | +--+
| +-----------+ | | +----- Lemiox
| | | | +--+
| | | | | +-- Dromus
| | | | +--+
| | +--+ +-- Cyprogenia
| | |
| | | +-- Sagittunio
| | | +--+
| | | | +-- Medionidus_conradicus **
+--+ +-----+
| | +-- Ptychobranchus
| +--+
| +-- Venustaconcha_ellipsiformis__2
|
| +-- Ellipsaria
| +--------------------+
| | +-- Truncilla
| |
| | +-------------------- Villosa
+--+ |
| | +-- Obovaria_olivaria
| | +--------+
| | | +-- Venustaconcha_ellipsiformis__1
| | +-----+
+--+ | | +-------- Epioblasma
| | +--+
| | | +----- Obovaria_unicolor
| | +--+
| | | +-- Obovaria_arkansasensis
| | +--+
| | +-- Obovaria_subrotunda
+--+
| +-------- Hamiota
| |
| +-----+ +-- Lampsilis_cardium
| | | +--+
| | | | +-- Lampsilis_ovata
| | +--+
| | | +-- Ortmanniana_pectorosa
+--+ +--+
| +-- Lampsilis_ornata
|
| +-- Ligumia
| +--------+
| | +-- Cambarunio
+--+
| +-------- Lampsilis_teres
+--+
| +----- Ortmanniana_ligamentina
+--+
| +-- Lampsilis_siliquoidea
+--+
+-- Leaunio
Lydeard et al., 1996 [Publ 2656], fig. 3
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 26 | 8 | 6 | -- |
+-------------- Potamilus_fragilis | --+ +----------- Ptychobranchus | | +--+ +-------- Medionidus_conradicus ** | | +--+ +----- Potamilus_purpuratus | | +--+----- Lampsilis | | +-- Ellipsaria +--+ +-- Villosa
Krebs et al., 2003 [Publ 2691], fig. 3
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 32 | 10 | 7 | -- |
+----- Ptychobranchus
+--------+
| | +-- Potamilus_fragilis
| +--+
| +-- Medionidus_conradicus **
--+
| +-- Villosa
| +--------+
| | +-- Ellipsaria
+--+
| +-------- Lampsilis_teres
+--+
| +----- Lampsilis_siliquoidea
+--+
| +-- Potamilus_purpuratus
+--+
+-- Potamilus_alatus
Lydeard et al., 1996 [Publ 2656], fig. 4
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 27 | 8 | 6 | -- |
+-------------------- Obliquaria --+ | +----------------- Medionidus_conradicus ** +--+ | +-------------- Ptychobranchus +--+ | +----------- Potamilus_fragilis +--+ | +-------- Potamilus_purpuratus +--+ | +----- Ellipsaria +--+ | +-- Villosa +--+ +-- Lampsilis
Huang et al., 2002 [Publ 2657], fig. 1
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 33 | 7 | 6 | -- |
+----------------- Medionidus_conradicus ** --+ | +-------------- Potamilus_fragilis +--+ | +----------- Ptychobranchus +--+ | +-------- Potamilus_purpuratus +--+ | +----- Lampsilis +--+ | +-- Villosa +--+ +-- Ellipsaria
Grobler et al., 2011 [Publ 3359], fig. 2
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 16 | 15 | 9 | -- |
+-------- Lemiox
+-----+
| | +----- Medionidus_conradicus **
| +--+
| | +-- Dromus
| +--+
--+ +-- Cyprogenia
|
| +----------- Potamilus
| |
| | +----- Lampsilis_siliquoidea
| | +--+
+--+ | | +-- Lampsilis_higginsii
| | +--+
| | +-- Ortmanniana
| |
| | +----- Lampsilis_fasciola
+--+--+
| | +-- Lampsilis_cardium
| +--+
| +-- Lampsilis_ovata
|
| +-- Cambarunio
| |
+-----+-- Ligumia
|
+-- Epioblasma
Huang et al., 2002 [Publ 2657], fig. 2
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 33 | 7 | 6 | -- |
-- Medionidus_conradicus **
Huang et al., 2019 [Publ 3843], fig. 2
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 199 | 13 | 11 | -- |
+-------------- Potamilus_leptodon | | +----------- Potamilus_alatus --+ | | | +-------- Venustaconcha | | | +--+ +-------- Leaunio | | | | +-- Ellipsaria | +-----+ +--+ +-- Truncilla | | +-- Medionidus_conradicus ** +-----+ | +-- Ptychobranchus | | +----- Cambarunio +--+ | +-- Ortmanniana +--+ +-- Lampsilis
Roe, 2013 [Publ 3571], fig. 4
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 10 | 10 | 5 | -- |
+----------- Obliquaria | --+----------- Lampsilis | | +-------- Medionidus_conradicus ** +--+ | +----- Ptychobranchus +--+ | +-- Cyprogenia +--+ +-- Dromus
Smith et al., 2019 [Publ 3951], fig. 2
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 40 | 35 | 19 | -- |
+----------------------- Obliquaria | | +-- Medionidus_conradicus ** | +--+ | | +-- Lemiox --+ +--------------+ | | | +-- Cyprogenia | | +--+ | | +-- Ptychobranchus | | +--+ +-------- Potamilus | +--------+ | | | +----- Atlanticoncha | | +--+ | | | +-- Ellipsaria | | +--+ +--+ +-- Truncilla | | +-- Hamiota | +-----------+ | | +-- Villosa | | +--+ +----------- Ligumia | | | | +----- Venustaconcha +--+ +--+ | | | +-- Obovaria | | +--+ +--+ +-- Epioblasma | | +----- Ortmanniana_pectorosa +--+ | +-- Ortmanniana_ligamentina +--+ +-- Lampsilis
Serb et al., 2003 [Publ 2659], fig. 2
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 28 | 6 | 5 | -- |
+----- Medionidus_conradicus ** --+ | +-- Dromus +--+ +-- Cyprogenia
Huang et al., 2019 [Publ 3843], fig. S3
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 197 | 13 | 11 | -- |
+-------------------- Potamilus_leptodon | --+ +----------------- Potamilus_alatus | | | | +-- Medionidus_conradicus ** +--+ +-----------+ | | +-- Ptychobranchus | | +--+ +-- Ellipsaria | +--------+ | | +-- Truncilla +--+ | +-------- Leaunio | | +--+ +-- Venustaconcha | +--+ | | +-- Cambarunio +--+ | +-- Ortmanniana +--+ +-- Lampsilis
Serb et al., 2003 [Publ 2659], fig. 3
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 28 | 6 | 5 | -- |
+----- Medionidus_conradicus ** --+ | +-- Dromus +--+ +-- Cyprogenia
Huang et al., 2019 [Publ 3843], fig. S4
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 199 | 13 | 11 | -- |
+----- Ellipsaria | +----- Potamilus_leptodon | +----- Medionidus_conradicus ** | +----- Potamilus_alatus | +----- Ptychobranchus --+ +----- Truncilla | +----- Venustaconcha | +----- Cambarunio | +----- Leaunio | | +-- Ortmanniana +--+ +-- Lampsilis
Turner et al., 2000 [Publ 2722], fig. 2
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 13 | 8 | 2 | -- |
+-------------------- Medionidus_conradicus ** | --+ +----------------- Lampsilis_teres | | | +----------------- Villosa +--+ | +-- Lampsilis_satura | +-----------+ | | +-- Lampsilis_cardium +--+ | +----------- Lampsilis_reeveiana | | +--+ +-------- Lampsilis_hydiana__1 | | +--+-------- Lampsilis_hydiana__2 | | +----- Lampsilis_siliquoidea__2 +--+ | +-- Lampsilis_siliquoidea__1 +--+ +-- Lampsilis_powellii
Burlakova et al., 2019 [Publ 3899], fig. 1
| tT | bi | riS | oT | roT | roS | iD | |
| 1 | 1 | 0 | 1 | 32 | 25 | 17 | -- |
+----------------- Toxolasma | | +-------------- Potamilus | | | | +-- Ellipsaria | +-----------+ --+ | +-- Truncilla | | | | +----- Medionidus_acutissimus ** | +--------+ | | | +-- Lemiox | | +--+ +--+ +-- Dromus | | +----------- Cambarunio | | | +----------- Leaunio | | | +----------- Villosa | | | | +-- Sagittunio | +--------+ +--+ +-- Lampsilis_ovata | | +----- Venustaconcha +-----+ | | +-- Epioblasma | +--+ | +-- Obovaria | | +-------- Lampsilis_teres +--+ | +----- Lampsilis_siliquoidea +--+ | +-- Lampsilis_hydiana +--+ +-- Lampsilis_straminea
