A doubt with terminology

[Shovelnose]

From Genera of the Asian Catfish Families Sisoridae and Erethistidae
(Teleostei: Siluriformes)ALFRED W. THOMSON & LAWRENCE M. PAGE :

Glyptothorax indicus Talwar 1991
Glyptothorax horai Shaw & Shebbeare 1936: 188, pl. Type locality: Streams of Terai [Ganges drainage], n. Bengal. Holotype: ZSI F11376/1. Subjectively invalid; secondarily preoccupied in Glyptothorax by Pteroglanis horai Fowler 1934, replaced by Glyptothorax indicus Talwar 1991.

Glyptothorax indicus Talwar in Talwar & Jhingran 1991: 654, fig. 210. Type locality: Streams ofTerai [Ganges drainage], n. Bengal. Holotype: ZSI F11376/1. Replacement name for Glyptothorax horai Shaw & Shebbeare 1936, secondarily preoccupied in Glyptothorax by Pteroglanis horai Fowler 1934.


Can anyone explain the above para for me??? I especially would like to know what secondarily preoccupied means here.

[Silurus]

A secondary homonym is one which occurs as a result of a reassignment in genus. Suppose we have two species originally described as Aus bus Smith, 1930 and Cus bus Jones, 1952. If research shows that Aus and Cus are the same genus (and we suppose that Aus is the senior name), then a new species name has to be used for Cus bus, since it would be reassigned to Aus and the name Aus bus is already in use.

This is what secondarily preoccupied means.

This is opposed to primary homonymy (two species described as Aus bus Smith, 1930 and Aus bus Jones, 1952).

[Shovelnose]

Ok. There is Glyptothorax horai,Fowler 1934 with Pteroglanis horai as a synonym which is considered valid. Where does it figure in this equation???

[Silurus]

Glyptothorax horai ≠ Pteroglanis horai

But Glyptothorax = Pteroglanis

As there cannot be two different species having one identical name (horai) in the same genus (Glyptothorax), a replacement name (G. indicus) must be found for the Shaw & Shebbeare species.

I hope this is clear enough. I’m finding it very difficult to dumb it down further.

[Shovelnose]

Ah. Ok. Got it now. That took a bit of time!!!!