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Page last updated
Wed 1 October 2025

The Freshwater Mussels (Unionoida) of the World (and other less consequential bivalves)

FM(U)otW(aolcb) is the web version of the MUSSEL Project Database. Follow the links to browse the data or use the custom Google search field. Either way, you win!

Search the database pages:

Bivalvia | Unionoida | Unionoidea | Unionidae | Parreysiinae | Lamellidentini

genus Trapezidens Bolotov, Vikhrev & Konopleva in Bolotov et al., 2017: cladomics
     6 Recent valid species (6 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 (6 total)
analyzed in 36 cladograms in 21 publications
maximum number of terminals in an analysis = 6 (mean = 2.75, median = 2)

Basic Monophyly

number of cladograms that test basic monophyly (i.e., more than 1 included species) = 21
maximum number of included terminals = 6, (mean = 4 median = 4)
proportion of cladograms that support basic monophyly = 1

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.


PCoA Ordination


NJ Tree

Bolotov et al., 2024 [Publ 4369], fig. 2

** Top Monophyly Cladogram ** ** Top Sister-Group Cladogram **

iTtTbiriSoTroTroSiD
6646561120
  +-------------------- Lamellidens                
--+                                                
  |  +----------------- Balwantia                  
  +--+                                             
     |  +-------------- Trapezidens_mogaungensis **   
     +--+                                          
        |  +----------- Trapezidens_exolescens **     
        +--+                                       
           |  +-------- Trapezidens_scutum **         
           +--+                                    
              |  +----- Trapezidens_yeti **           
              +--+                                 
                 |  +-- Trapezidens_angustior **      
                 +--+                              
                    +-- Trapezidens_dolichorhynchus **

Bolotov et al., 2024 [Publ 4369], fig. S1

iTtTbiriSoTroTroSiD
6646571120
  +-------------------- Lamellidens                
--+                                                
  |  +----------------- Balwantia                  
  +--+                                             
     |  +-------------- Trapezidens_mogaungensis **   
     +--+                                          
        |  +----------- Trapezidens_exolescens **     
        +--+                                       
           |  +-------- Trapezidens_scutum **         
           +--+                                    
              |  +----- Trapezidens_yeti **           
              +--+                                 
                 |  +-- Trapezidens_dolichorhynchus **
                 +--+                              
                    +-- Trapezidens_angustior **

Bolotov et al., 2022 [Publ 4252], fig. S1

iTtTbiriSoTroTroSiD
6646551012
  +----------------- Lamellidens                
--+                                             
  |  +-------------- Trapezidens_mogaungensis **   
  +--+                                          
     |  +----------- Trapezidens_scutum **         
     +--+                                       
        |  +-------- Trapezidens_exolescens **     
        +--+                                    
           |  +----- Trapezidens_yeti **           
           +--+                                 
              |  +-- Trapezidens_dolichorhynchus **
              +--+                              
                 +-- Trapezidens_angustior **

Bolotov et al., 2022 [Publ 4252], fig. 2

iTtTbiriSoTroTroSiD
6636551011
  +-------------- Lamellidens                
  |                                          
--+  +----------- Trapezidens_mogaungensis **   
  |  |                                       
  +--+  +-------- Trapezidens_exolescens **     
     |  |                                    
     +--+  +----- Trapezidens_scutum **         
        |  |                                 
        +--+  +-- Trapezidens_angustior **      
           |  |                              
           +--+-- Trapezidens_dolichorhynchus **
              |                              
              +-- Trapezidens_yeti **

Bolotov et al., 2022 [Publ 4239], fig. S2

iTtTbiriSoTroTroSiD
553553913
  +-------------- Lamellidens                
--+                                          
  |  +----------- Trapezidens_scutum **         
  +--+                                       
     |  +-------- Trapezidens_exolescens **     
     +--+                                    
        |  +----- Trapezidens_yeti **           
        +--+                                 
           |  +-- Trapezidens_dolichorhynchus **
           +--+                              
              +-- Trapezidens_angustior **

Konopleva et al., 2020 [Publ 4072], fig. 2

iTtTbiriSoTroTroSiD
55357413
  +-------------- Lamellidens                
--+                                          
  |  +----------- Trapezidens_scutum **         
  +--+                                       
     |  +-------- Trapezidens_exolescens **     
     +--+                                    
        |  +----- Trapezidens_yeti **           
        +--+                                 
           |  +-- Trapezidens_angustior **      
           +--+                              
              +-- Trapezidens_dolichorhynchus **

Bolotov et al., 2022 [Publ 4250], fig. S4

iTtTbiriSoTroTroSiD
55254414
  +----------- Lamellidens                
  |                                       
--+  +-------- Trapezidens_scutum **         
  |  |                                    
  +--+  +----- Trapezidens_exolescens **     
     |  |                                 
     +--+  +-- Trapezidens_dolichorhynchus **
        |  |                              
        +--+-- Trapezidens_angustior **      
           |                              
           +-- Trapezidens_yeti **

Bolotov et al., 2022 [Publ 4239], fig. S1

iTtTbiriSoTroTroSiD
552553912
  +----------- Lamellidens                
  |                                       
--+  +-------- Trapezidens_exolescens **     
  |  |                                    
  +--+  +----- Trapezidens_scutum **         
     |  |                                 
     +--+  +-- Trapezidens_angustior **      
        |  |                              
        +--+-- Trapezidens_dolichorhynchus **
           |                              
           +-- Trapezidens_yeti **

Bolotov et al., 2022 [Publ 4239], fig. 2

iTtTbiriSoTroTroSiD
553553915
  +----------- Lamellidens                
  |                                       
--+        +-- Trapezidens_exolescens **     
  |  +-----+                              
  |  |     +-- Trapezidens_scutum **         
  +--+                                    
     |  +----- Trapezidens_angustior **      
     +--+                                 
        |  +-- Trapezidens_dolichorhynchus **
        +--+                              
           +-- Trapezidens_yeti **

Bolotov et al., 2022 [Publ 4250], fig. 8

iTtTbiriSoTroTroSiD
553544411
  +-------------- Lamellidens                
--+                                          
  |  +----------- Trapezidens_exolescens **     
  +--+                                       
     |  +-------- Trapezidens_scutum **         
     +--+                                    
        |  +----- Trapezidens_yeti **           
        +--+                                 
           |  +-- Trapezidens_angustior **      
           +--+                              
              +-- Trapezidens_dolichorhynchus **

Bolotov et al., 2020 [Publ 4100], fig. S1

iTtTbiriSoTroTroSiD
4424108412
  +----------- Lamellidens                
--+                                       
  |  +-------- Trapezidens_exolescens **     
  +--+                                    
     |  +----- Trapezidens_scutum **         
     +--+                                 
        |  +-- Trapezidens_dolichorhynchus **
        +--+                              
           +-- Trapezidens_angustior **

Bolotov et al., 2020 [Publ 4100], fig. 1

iTtTbiriSoTroTroSiD
4424114412
  +----------- Lamellidens                
--+                                       
  |  +-------- Trapezidens_exolescens **     
  +--+                                    
     |  +----- Trapezidens_scutum **         
     +--+                                 
        |  +-- Trapezidens_dolichorhynchus **
        +--+                              
           +-- Trapezidens_angustior **

Bolotov et al., 2017 [Publ 3764], fig. S1

iTtTbiriSoTroTroSiD
3313122813
  +-------- Lamellidens                
--+                                    
  |  +----- Trapezidens_exolescens **     
  +--+                                 
     |  +-- Trapezidens_dolichorhynchus **
     +--+                              
        +-- Trapezidens_angustior **

Huang et al., 2019 [Publ 3843], fig. 2

iTtTbiriSoTroTroSiD
3313196813
  +-------- Lamellidens                
--+                                    
  |  +----- Trapezidens_exolescens **     
  +--+                                 
     |  +-- Trapezidens_dolichorhynchus **
     +--+                              
        +-- Trapezidens_angustior **

Huang et al., 2019 [Publ 3843], fig. S4

iTtTbiriSoTroTroSiD
3313196813
  +-------- Lamellidens                
--+                                    
  |  +----- Trapezidens_exolescens **     
  +--+                                 
     |  +-- Trapezidens_angustior **      
     +--+                              
        +-- Trapezidens_dolichorhynchus **

Huang et al., 2019 [Publ 3843], fig. S3

iTtTbiriSoTroTroSiD
3313194813
  +-------- Lamellidens                
--+                                    
  |  +----- Trapezidens_exolescens **     
  +--+                                 
     |  +-- Trapezidens_angustior **      
     +--+                              
        +-- Trapezidens_dolichorhynchus **

Konopleva et al., 2017 [Publ 3807], fig. 5

iTtTbiriSoTroTroSiD
2202331--
  +----- Lamellidens                
--+                                 
  |  +-- Trapezidens_exolescens **     
  +--+                              
     +-- Trapezidens_dolichorhynchus **

Konopleva et al., 2017 [Publ 3807], fig. 6

iTtTbiriSoTroTroSiD
22022931--
  +----- Lamellidens                
--+                                 
  |  +-- Trapezidens_exolescens **     
  +--+                              
     +-- Trapezidens_dolichorhynchus **

Bolotov et al., 2017 [Publ 3761], fig. S2

iTtTbiriSoTroTroSiD
220213761--
  +----- Lamellidens                
--+                                 
  |  +-- Trapezidens_dolichorhynchus **
  +--+                              
     +-- Trapezidens_exolescens **

Bolotov et al., 2017 [Publ 3761], fig. S1

iTtTbiriSoTroTroSiD
220213761--
  +----- Lamellidens                
--+                                 
  |  +-- Trapezidens_dolichorhynchus **
  +--+                              
     +-- Trapezidens_exolescens **

Bolotov et al., 2018 [Publ 3826], fig. 2

iTtTbiriSoTroTroSiD
22028141--
  +----- Lamellidens                
--+                                 
  |  +-- Trapezidens_exolescens **     
  +--+                              
     +-- Trapezidens_dolichorhynchus **

Konopleva et al., 2023 [Publ 4269], fig. S1_4

iTtTbiriSoTroTroSiD
11015511--
  +-- Trapezidens_exolescens **
--+                         
  +-- Lamellidens

Dai et al., 2024 [Publ 4385], fig. 3-BI

iTtTbiriSoTroTroSiD
11013000--
-- Trapezidens_exolescens **

Pfeiffer et al., 2019 [Publ 3937], fig. 6

iTtTbiriSoTroTroSiD
11015611--
  +-- Trapezidens_dolichorhynchus **
--+                              
  +-- Lamellidens

Wu et al., 2021 [Publ 4366], fig. 6

iTtTbiriSoTroTroSiD
11019031--
  +-- Trapezidens_exolescens **
--+                         
  +-- Lamellidens

Whelan et al., 2011 [Publ 3380], fig. 1-MP

iTtTbiriSoTroTroSiD
11013511--
  +-- Lamellidens                
--+                              
  +-- Trapezidens_dolichorhynchus **

Lopes-Lima et al., 2017 [Publ 3745], fig. 1-2

iTtTbiriSoTroTroSiD
11017900--
-- Trapezidens_dolichorhynchus **

Dai et al., 2024 [Publ 4386], fig. 5-BI

iTtTbiriSoTroTroSiD
11012000--
-- Trapezidens_exolescens **

Whelan et al., 2011 [Publ 3380], fig. 1-ML

iTtTbiriSoTroTroSiD
11013511--
  +-- Lamellidens                
--+                              
  +-- Trapezidens_dolichorhynchus **

Dai et al., 2024 [Publ 4386], fig. 5-ML

iTtTbiriSoTroTroSiD
11012000--
-- Trapezidens_exolescens **

Pfeiffer et al., 2018 [Publ 3827], fig. 2

iTtTbiriSoTroTroSiD
11012711--
  +-- Trapezidens_dolichorhynchus **
--+                              
  +-- Lamellidens

Pfeiffer & Graf, 2015 [Publ 3620], fig. 2

iTtTbiriSoTroTroSiD
11013911--
  +-- Trapezidens_dolichorhynchus **
--+                              
  +-- Lamellidens

Wu et al., 2021 [Publ 4366], fig. 2_I

iTtTbiriSoTroTroSiD
11019031--
  +-- Trapezidens_exolescens **
--+                         
  +-- Lamellidens

Jeratthitikul et al., 2019 [Publ 3922], fig. 1

iTtTbiriSoTroTroSiD
11012211--
  +-- Lamellidens           
--+                         
  +-- Trapezidens_exolescens **

Pfeiffer et al., 2019 [Publ 3937], fig. 4-5

iTtTbiriSoTroTroSiD
11015611--
  +-- Trapezidens_dolichorhynchus **
--+                              
  +-- Lamellidens

Dai et al., 2024 [Publ 4385], fig. 3-ML

iTtTbiriSoTroTroSiD
11013000--
-- Trapezidens_exolescens **
 
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