Key to the Genus

Below is a key to the genus. Please note, Sisubiotus wuyishanensis species inquirenda has been included in the key as originally presented by Zhang & Sun (2014), but considerable uncertainty remains concerning the morphology and validity of the species. Most importantly, this includes questions about the purported lack of egg areolation that was included as the primary character distinguishing this species from its congeners (Stec et al., 2021).

1. Leg granulation present and clearly visible for at least the fourth pair of legs. OCA well-developed and comprising three bands of teeth. Eggs areolated................................................................................ 2

- Legs without granulation. OCA comprising two rows of teeth (e.g. the first band of teeth sensu Kaczmarek et al. [2020] absent or not visible in LM). Eggs without areolae................................. Sis. wuyishanensis (Zhang & Sun, 2014)

2. The second band of the OCA comprising an anterior row of longitudinally elongated teeth and several posterior rows of numerous smaller, granular teeth......................................................................... 3

- The second band of the OCA comprising a single row of longitudinal elongated teeth with only a few posterior granular teeth sometimes present.............................................................. Sis. grandis (Richters, 1911)

3. Fine granulation clearly visible on the external surfaces of legs I–III. Lunules of the claws of legs IV smooth. Eggs with a double row of areolae surrounding most of the egg processes................................................... 4

- Fine granulation absent on leg I. Lunules of the claws of legs IV dentate. Eggs with a “1+3” pattern of areolae surrounding most of the egg processes................................................................. Sis. splendidus sp. nov.

4. Egg process walls with a clear labyrinthine layer visible in LM........... Sis. hakaiensis Vecchi, Choong & Calhim, 2022

- Egg process walls a labyrinthine layer not clearly visible in LM......................... Sis. spectabilis (Thulin, 1928)