Arotrobates granulatus Luxton, 1992

Arotrobates granulatus Luxton, 1992 View in CoL

Larva and protonymph unknown.

Deutonymph

Length (N = 2): 243–265 (mean 254 μm).

Gastronotic region. Fifteen pairs of normal spiniform notogastral setae (8–12 µm); c 1-3, da, dm, dp, la, lm, lp, h 1-3, p 1-3.

Podosoma and venter. Epimeral setation 1-0-1-1. Two pairs of short genital setae (ca. 5 µm) arranged in longitudinal row. Three pairs of vestigial adanal setae flanking anal valves. One pair of vestigial anal setae (an 1).

Legs ( Figure 11 View Figure 11 ). Setation and solenidia are shown in Table 5 View Table 5 .

Tritonymph

Length (N = 5): 274–299 (mean 285 μm).

Gastronotic region ( Figure 10 View Figure 10 (c)). No difference to deutonymph.

Podosoma and venter ( Figure 10 View Figure 10 (d)). Epimeral setation 1-0-1-1.

Three pairs of short genital setae g 1-3 (4–5 µm) in longitudinal row. Three pairs of vestigial adanal setae. Anal setae an 1 developed in this stage.

Legs. Setation and solenidia are shown in Table 5 View Table 5 .

Remarks

When Luxton (1992) erected the genus Arotrobates , he provided sketchy drawings of the legs of A. lanceolatus and mentioned at least in the key that members of this genus show conspicuous crests on all femora. Apart from this info, he provided very few further details on leg features whereas he mostly reported appearances of solenidia, for both known species. Later, Karasawa and Aoki (2005) redescribed A. granulatus from the southern and central Ryukyus and also gave only vague information on the legs, e.g. they provided length of each segment and wrote a sentence about pigmentation, but in contrast to Luxton (1992) they did not mention ventral carinae on femora at all. The latter trait, however, is present in the Japanese specimens and represents a prominent feature that is already developed in the juvenile stages. The setation and solenidia, presented herein for the first time in detail, are only based on Japanese A. granulatus material. No porous areas could be detected on any leg segment in any stage. Another characteristic trait of Arotrobates are the plough-like ventral epimeral carinae and although this feature is not developed in any juvenile stage, the epimeral integument of the nymphs appears to be more folded and less tight than in any other selenoribatid juvenile. This extension of integumental surface could already be an indication of the later developing ventral epimeral carinae.