(Figs 4–6)
Type material. HOLOTYPE, female, 6.2 mm, MV J60572. PARATYPE, 1 specimen, MV J15792; 76 km south of Point Hicks, Victoria, Australia, 38°29.33'S 149°19.98'E, 1840 m, sandy mud, fine shell, WHOI epibenthic sled, 26 October 1988, G.C.B. Poore et al. on RV Franklin, stn SLOPE 69.
Type locality. 76 km south of Point Hicks, Victoria, Australia, 38°29.33'S 149°19.98'E, 1840 m depth.
Etymology. The specific name refers to the vessel, HM Bark Endeavour, on which Lieutenant James Cook was sailing when he named the nearest point to the type locality, Point Hicks; used as a noun in apposition.
Diagnosis. Head lobe broadly subtriangular. Epistome strongly produced, subtriangular with acute apex. Gnathopod 1 propodus palm transverse, straight; dactylus slightly over-reaching palm, with 1 subterminal spine on inner margin. Gnathopod 2 minutely subchelate; propodus length 2.2 × breadth. Epimeron 1 anteroventral corner rounded. Epimeron 3 posteroventral corner produced into large spine. Uropod 2 inner ramus not incised. Uropod 3 outer ramus article 2 long, 0.6 × article 1. Telson length 1.2 × breadth, cleft 38 %.
Remarks. Hirondellea endeavour is the only known Australian species with a transverse palm on gnathopod 1. However, H. abyssalis, H. antarctica, H. brevicaudata and H. guyoti all have transverse palms. Hirondellea endeavour shares a non-constricted uropod 2 inner ramus and a medium cleft telson with H. abyssalis and H. brevicaudata. It differs from both of these species in the posteroventral corner of epimeron 3 which is developed into a large spine.
Distribution. South-eastern Australia in 1840 m depth.