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Page last updated
Thu 3 September 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 | Unionida | Unionoidea | Unionidae | Parreysiinae | Lamellidentini

genus Trapezidens Bolotov, Vikhrev & Konopleva in Bolotov et al., 2017: cladomics
     6 Recent valid species (6 total species)

Cladomics Summary

number of species = 6 (6 total)
analyzed in 38 cladograms in 23 publications
maximum number of terminals in an analysis = 6 (mean = 2.79, median = 2)

Basic Monophyly

number of cladograms that test basic monophyly (i.e., more than 1 included species) = 22
maximum number of included terminals = 6, (mean = 4.09 median = 4.5)
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., 2022 [Publ 4252], fig. 2

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

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 **

Campbell & Lydeard, 2026 [Publ 4810], fig. 6-14

iTtTbiriSoTroTroSiD
66466251120
  +----------------- Balwantia                  
--+                                             
  |  +-------------- Trapezidens_mogaungensis **   
  +--+                                          
     |  +----------- Trapezidens_exolescens **     
     +--+                                       
        |  +-------- Trapezidens_scutum **         
        +--+                                    
           |  +----- Trapezidens_yeti **           
           +--+                                 
              |  +-- Trapezidens_angustior **      
              +--+                              
                 +-- Trapezidens_dolichorhynchus **

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. 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 4250], fig. 8

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

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., 2020 [Publ 4100], fig. 1

iTtTbiriSoTroTroSiD
4424113412
  +----------- Lamellidens                
--+                                       
  |  +-------- Trapezidens_exolescens **     
  +--+                                    
     |  +----- Trapezidens_scutum **         
     +--+                                 
        |  +-- Trapezidens_dolichorhynchus **
        +--+                              
           +-- Trapezidens_angustior **

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

iTtTbiriSoTroTroSiD
4424107412
  +----------- Lamellidens                
--+                                       
  |  +-------- Trapezidens_exolescens **     
  +--+                                    
     |  +----- Trapezidens_scutum **         
     +--+                                 
        |  +-- Trapezidens_dolichorhynchus **
        +--+                              
           +-- Trapezidens_angustior **

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

iTtTbiriSoTroTroSiD
3313121813
  +-------- Lamellidens                
--+                                    
  |  +----- Trapezidens_exolescens **     
  +--+                                 
     |  +-- Trapezidens_dolichorhynchus **
     +--+                              
        +-- Trapezidens_angustior **

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

iTtTbiriSoTroTroSiD
3313197813
  +-------- Lamellidens                
--+                                    
  |  +----- Trapezidens_exolescens **     
  +--+                                 
     |  +-- Trapezidens_angustior **      
     +--+                              
        +-- Trapezidens_dolichorhynchus **

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

iTtTbiriSoTroTroSiD
3313195813
  +-------- Lamellidens                
--+                                    
  |  +----- Trapezidens_exolescens **     
  +--+                                 
     |  +-- Trapezidens_angustior **      
     +--+                              
        +-- Trapezidens_dolichorhynchus **

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

iTtTbiriSoTroTroSiD
3313197813
  +-------- Lamellidens                
--+                                    
  |  +----- Trapezidens_exolescens **     
  +--+                                 
     |  +-- Trapezidens_dolichorhynchus **
     +--+                              
        +-- Trapezidens_angustior **

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

iTtTbiriSoTroTroSiD
220213661--
  +----- Lamellidens                
--+                                 
  |  +-- Trapezidens_dolichorhynchus **
  +--+                              
     +-- Trapezidens_exolescens **

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

iTtTbiriSoTroTroSiD
22028041--
  +----- Lamellidens                
--+                                 
  |  +-- Trapezidens_exolescens **     
  +--+                              
     +-- 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
220213661--
  +----- Lamellidens                
--+                                 
  |  +-- Trapezidens_dolichorhynchus **
  +--+                              
     +-- Trapezidens_exolescens **

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

iTtTbiriSoTroTroSiD
11012100--
-- Trapezidens_exolescens **

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

iTtTbiriSoTroTroSiD
11012100--
-- Trapezidens_exolescens **

Dai et al., 2026 [Publ 4757], fig. 3

iTtTbiriSoTroTroSiD
11013300--
-- Trapezidens_exolescens **

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

iTtTbiriSoTroTroSiD
11013000--
-- Trapezidens_exolescens **

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

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

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

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

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

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

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

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

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

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

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

iTtTbiriSoTroTroSiD
11013000--
-- Trapezidens_exolescens **

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

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

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

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

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

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 **

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

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