Taxonomic key for species of Treadwellphysa

(based on Molina-Acevedo and Carrera-Parra 2017)

1. With compound falcigers and spinigers .............................................................................. 2 - With only compound falcigers .................................................................................................. 5

2(1). With compound spinifalcigers.................................................................................................... 3 - Without compound spinifalcigers............................................................................................. 4

3(2). Postchaetal lobes longer than chaetal lobe in first 4 chaetigers; compound falcigers with long blades 2 times longer than the short blades in anterior region; compound spinifalciger present in first 22 chaetigers (in specimens with L10 = 5 mm, W10 = 2 mm)......................... ......................... T. amadae (Fauchald, 1977)

- Postchaetal lobes as long as chaetal lobe in first 4 chaetigers; compound falciger with long blades 3 times longer than short blades in the anterior region; compound spinifalciger present in first 46 chaetigers (in specimens with L10 = 5.6 mm, W10 = 2.3 mm)....................................................................................................... .................................................. T. yucatanensis Molina-Acevedo and Carrera-Parra, 2017

4(2). With compound spinigers only in anterior chaetigers; compound falcigers in all chaetigers.................................................................... T. mixta (Fauchald, 1970) comb. nov.

- With compound spinigers in all chaetigers; compound falcigers only on chaetigers 30 – 54.................................... .................................... T. dartevellei (Monro, 1936) comb. nov.

5(1). With compound spinifalcigers.................................................................................................... 6 - Without compound spinifalcigers.............................................................................................. 7

6(5). Subacicular hooks reddish along most of its length, translucent on the distal tip. ................................................................................................................................ T. rizzoae sp. nov.

- Subacicular hooks translucent.............................................................. T. villabolosi sp. nov.

7(5). Postchaetal lobes conical, longer than chaetal lobes in first 4 chaetigers; compound falcigers with long blade 2.5 times longer than short blade in anterior chaetigers.................................................................................... T. languida (Treadwell, 1921)

- Postchaetal lobes rounded, as long as chaetal lobes in first 4 chaetigers; compound falcigers with long blades 3 times longer than short blades in anterior chaetigers.................. T. veracruzensis (de León-González and Díaz-Castañeda, 2006)