By the present contribution by Modest Guţu, the family Leptocheliidae enriched with 29 new taxa (a subfamily, seven genera and 21 species), as it results from the list, hereinafter. Subfamily Leptocheliinae Lang, 1973: - Genus Alloleptochelia n. g., with the species: A. angusta n. sp., A. heardi n. sp., A. insolita n. sp., A. monotricha n. sp. and A. multiarticulata n. sp.; - Genus Chondrochelia n. g., with the species: C. andersoni n. sp., C. baliensis n. sp., C. dentitruncata n. sp. and C. distincta n. sp.; - Genus Kalloleptochelia n. g., with the species: K. maiorina n. sp., K. pauxilla n. sp. and K. robusta n. sp.; - Genus Leptochelia Dana, 1849, with the species: L. afrieurina n. sp. and L. splendida n. sp.; - Genus Paraleptochelia n. g., with the species P. magnispina n. sp.; - Genus Permixtimella n. g., with the species P. oculifurcillata n. sp.; - Genus Poorea Edgar, 2012, with the species P. obscurus; n. sp. and P. tanzaniensis n. sp. Subfamily Konariinae Bamber, 2013: - Genus Antiparus n. g. with the species A. longisetosus n. sp. Subfamily Metaleptocheliinae nov.: - Genus Metaleptochelia n. g. with the species M. estafricana n. sp. and M. vestpacifica n. sp. Also, the female of the species Leptochelia forresti (Stebbing, 1896), unknown up to now, is described and illustrated for the first time, and the male is minutely redescribed. It is for the first time when a large number of taxa (six genera and 12 species) of the family Leptocheliidae are minutely described on the basis of both sexes, this allowing the establishing of the common morphological features in the males and females of the same species, as well of those present at the genus level. The males of the genus Antiparus n. g. and of the species Antiparus longisetosus n. sp., Poorea obscurus n. sp. and P. tanzaniensis n. sp. and the females of the genus Kalloleptochelia n. g. and of the species Alloleptochelia insolita n. sp., A. multiarticulata n. sp., Kalloleptochelia maiorina n. sp., K. pauxilla n. sp., K. robusta n. sp. and Leptochelia afrieurina n. sp. are unknown. The identification keys of the leptocheliid subfamilies are presented, for the genera of the subfamilies Leptocheliinae and Konariinae, as well as the identification keys of the species of the genera Leptochelia, Alloleptochelia n. g., Kalloleptochelia n. g., Makassaritanais Guţu, 2012, Metaleptochelia n. g. and Poorea Edgar, 2012, and of the new species of the genus Chondrochelia n. g. Considering that the females and males of the species of the family Leptocheliidae have different morphological features, the key of the genera of the subfamily Leptocheliinae (the most numerous within the family, having 20 genera) refers both to the common features of the two sexes (when it was possible) and separately, for females and males allowing a more precise identification. The studied material provided from the Indo-West-Pacific shallow waters. The comments from the Addendum refer to the recent English version of the chapter Order Tanaidacea (revised and updated by Kim Larsen after the original text co-authored by Modest Guţu and the late Jürgen Sieg), from the well-known Traité de Zoologie (Tome VII, Fascicule III A, Crustacés Pracarides), founded by P.-P. Grassé. That new version contains numerous unacceptable mistakes since the author was not consulted or at least informed about the re-publication, as it would have been ethically appropriate.