Key to genera currently within the Subfamily Parapseudinae Guţu, 1981 (modified from Guţu 2008, Heard & Morales-Núñez 2011) 1. All pleonites dorsally with complete anterior transverse row of short setulate setae................................. 2 - All pleonites dorsally lacking either complete or incomplete anterior transverse row of short setulate setae............... 3 - Pleonite-1 only with dorsally incomplete or complete anterior transverse row of short setulate setae................... 9 2. Antennule inner flagellum biarticulated; male with large ventral prolongation on cheliped carpus......... Halmyrapseudes - Antennule inner flagellum multiarticulate; male lacking ventral prolongation on cheliped carpus................................................................................. Pseudohalmyrapseudes Larsen & Hansknecht, 2004 3. Pereopod-4 with dactylus greatly reduced, shorter than adjacent propodal setae.................................... 4 - Pereopod-4 with dactylus distinct, usually longer than adjacent propodal seta....................................... ................................................................................................... 6 4. Cheliped and pereopod-1 exopodite without plumose setae on last article [Five pairs of pleopods]............................................................................................... Ascumnella Guţu & Heard, 2002 - Cheliped and pereopod- 1 exopodite with plumose setae on last article [4 or 5 pairs of pleopods....................... 5 5. Carapace ventral margins with spiniform setae; antennule peduncle article 1 with 2-3 spiniform setae on inner margin...................................................................................... Brachylicoa Guţu, 2006 - Carapace having ventral margins lacking spiniform setae; antennule peduncle article-1 lacking spiniform setae on inner margin [Four or five pairs of pleopods]................................................................ Parapseudes 6. Pereopod-2 having basis with strongly-developed spiniform seta on anterior margin.......................................................................................... Akanthoparapseudes Heard & Morales-Núñez, 2011 -- Pereopod-2 with basis lacking spine on anterior margin....................................................... 7 7. Antennule accessory flagellum biarticulate; pereopod 6 basis without plumose setae............................................................................................. Aponychos Bamber, Chatterjee & Marshall, 2012 - Antennule accessory flagellum multiarticulate; pereopod 6 basis with plumose setae................................ 8 8. Mandibular palp article 1 with several setae; pereopod 1 basis with spiniform setae on ventral and dorsal margins.......................................................................................... Podictenius Guţu, 2006 - Mandibular palp article-1 with one seta; pereopod 1 basis without spiniform setae on ventral and dorsal margins............................................................................... Longipedis Larsen & Shimomura, 2006 9. Pleotelson round or, in rare cases, elongate with rows of short setae on margins; antenna article 5 longer than previous four combined, having numerous, long plumose setae on inner margin..................................... Discapseudes - Pleotelson elongate, without row of short setae on margins; antenna with article 5 shorter than previous four articles combined, lacking row of long, plumose setae...................................................................... 10 10. Pleonite-1 dorsally with an incomplete anterior transverse row of short setulate setae................ Pseudolongiflagrum - Pleonite-1 dorsally with complete anterior transverse row of short setulate setae................................... 11 11. Antenna with long setae on inner margin of second article.......................................... Longiflagrum - Antenna without long setae on inner margin of second article................................................. 12 12. Pleonites with very long lateral plumose setae.......................................... Gutuapseudes Edgar, 1997 - Pleonites lacking very long lateral plumose setae........................................................... 13 13. Pleopods foliaceous, not slender........................................................................ 14 - Pleopods not foliaceous, slender........................................................................ 15 14. Antennal peduncle article 1 with plumose setae near medial edge; labium with three terminal spiniform setae; pereopod 1 propodus with at least four ventral spiniform setae, and dactylus subequal to propodus length............... Mexctenapseudes - Antenna peduncle article 1 without plumose setae near medial edge; labium with two terminal spiniform setae; pereopod 1 propodus with one or two ventral spiniform setae, and dactylus much shorter than propodus............... Ctenapseudes 15. Basis of pereopods 1 and 2 with distal transverse row of setae........ Remexudes Błażewicz-Paszkowycz & Bamber, 2007 - Basis of pereopods 1 and 2 without distal transverse row of setae.............................................. 16 16. Antenna first peduncle article with plumose setae on medial margin....................... Pseudoapseudes Guţu, 1981 - Antenna first peduncle article without plumose setae on medial margin......................... Saltipedis Guţu, 1995

Published as part of Drumm, David T. & Heard, Richard W., 2022, Mexctenapseudes boeschi, a new tanaidacean genus and species (Crustacea: Peracarida: Apseudomorpha: Parapseudidae) from the Mexican coast of Campeche with the designation of a new related Australian genus to receive Longiflagrum caeruleus (Boesch, 1973), pp. 200-222 in Zootaxa 5116 (2) on pages 216-217, DOI: 10.11646/zootaxa.5116.2.2, http://zenodo.org/record/6367153