Neoleptastacus spinicaudatus Nicholls 1945

(2) spinicaudatus -group Diagnosis. Anal somite without paired dorsolateral processes. Anal operculum weakly developed, without rounded medial extension (except for A. pseudishikarianus sp. nov.). P1 exp-1 with outer spine; exp-3 with four setae/ spines. P1 enp-2 with outer spine and inner geniculate seta distally. P2 exp-2 with outer spine of normal length (not extending far beyond distal margin of exp-3). Endopod P2–P3 2-segmented; P2 enp-2 with inner seta and two distal spines; P3 enp-2 with two distal spines (outer one fused to segment). P4 enp-2 with normally developed outer seta. Species included. N. spinicaudatus Nicholls, 1945, N. ishikarianus (Itô, 1968), N. clasingi (Mielke, 1985), N. pacificus (Mielke, 1985), N. spicatus (Mielke, 1985) and N. pseudishikarianus sp. nov. The spinicaudatus -group accommodates six morphologically very similar species, all of which are currently restricted to the Pacific Ocean. All species display the plesiomorphic armature on P1–P4, except for N. pacificus which lacks the inner seta on P4 exp-3 (Table 2). In the absence of any morphology-based apomorphies that could support the common origin of these species, assessment of the potential monophyly of this species group will have to await the arrival of molecular sequence data. Sak et al. (2008) provided a key to the members of the spinicaudatus - group (except N. pseudishikarianus sp. nov.). Chappuis & Rouch’s (1961) description of Neoleptastacus accraensis (Lang, 1965) is inadequate and incomplete. Based on a reinterpretation of the armature pattern of the P3 endopod (see below) the species is treated here as a species inquirenda in the spinicaudatus -group.