I've been looking over the available material for Leonidae, this is what I have found so far:

Contact: The Dynchia (Peter Rasmussen), JTAS 24 - Called Leonidae, Melande Sector, Hinterworlds is called The Margin Sector. Note from Loren Wiseman states, the article was not fully compatible with Atlas of the Imperium (Which only covered Hinterworlds.)

Hinterworlds (Rob Caswell & Karl Johnson), Challenge 39 - Defines the Sector Rasmussen called 'The Margin'. Provides subsector names for the Spinward subsctors of Leonidae. Places the Hiver client called The Council of Leh Perash in the approximate astrographic location Rasmussen placed the Dynchia (Subector P of Hinterwords + Subsectors I, J M & N of Leonidae(Melande))

GURPS Traveller: Humaniti (Various) - Contains a revised Dynchia writeup which places them at an unspecified location in Leonidae and adds a new(?) Human subspecies called the Kargol whose homeworld is located at Leonidae 1205 (On Travellermap.com this is an empty hex in Sastanna SubSector) Also mentioned in the Kargol backstory is a Solomani colony world called Shan's Landing located one parsec away from Kargol (Also not on the Travellermap.com map of Leonidae)

I am thinking with the current revival of interest it might be worthwhile to put together some kind of working group to sort out the sector, though we may need to generate a new map.

Anyone interested?

Graham