Limbodessus fridaywellensis (Watts & Humphreys, 2001)

Michat, Mariano C., Alarie, Yves & Watts, Chris H. S., 2012, 3584, Zootaxa 3584 (1), pp. 1-110 : 43-44

Limbodessus fridaywellensis (Watts & Humphreys, 2001)

(Figs 77–80)

Source of material. One specimen of instar III was used for the description ( Table 1). Larva was collected in association with adults at the following locality: Australia, Raeside palaeovalley, Depot Springs calcrete, site 425, BES 8414, 28.05S, 120.03917E, 28–VI–2000, coll. W. F. Humphreys and S. Hinze.

Diagnosis (instar III). smaller species (HL less than 0.50 mm); head (Fig. 77) subpentagonal; nasale subtriangular; half-circle of dense spinulae on lateroventral margins of nasale absent; hole-like structure on ventrodistal surface of nasale absent; lateral margins of nasale not inflated in dorsal view; lateral branches of nasale minute; slender spinulae anterior to seta FR13 scarce (20 or less); occipital foramen well developed (HW/OCW less than 1.90); occipital suture present; lateral margins of parietal straight; secondary spiniform setae on lateral margins of parietal scarce; seta AN2 present; distal half of MN broad; setae LA3, LA4, LA5 and LA8 hair-like; secondary setae on U absent (Fig. 80).

Instar I. Not available.

Instar II. Not available.

Instar III (Figs 77–80). Head (Fig. 77). A3 less than 2.25 times longer than A1; A3 more than 1.45 times longer than A2; MN less than 4.85 times longer than broad; MP less than 1.75 times longer than labial palpus; MP2 2.10–3.10 times longer than MP3; LP2 more than 0.65 times as long as LP1. Legs (Figs 78–79). L3 2.25–2.85 times longer than HW. Abdomen (Fig. 80). U more than 3.10 times longer than LAS; U more than 2.30 times longer than HW; U1 less than 0.60 times as long as U2. Chaetotaxy. Anteroventral margin of nasale with 31 lamellae clypeales distributed in a single row; pro- and mesoCO without anterior secondary setae; pro-, meso- and metaCO without posterior secondary setae; proCO with less than 11 secondary setae; metaCO with less than 20 secondary setae; anterodorsal secondary setae on pro- and metaFE absent; metaFE with less than 12 anteroventral absent; mesoTI with less than 4 anteroventral secondary setae; metaTI with less than 9 anteroventral secondary setae; metaTI with less than 16 secondary setae; secondary setae on proTA absent; anterodorsal, anteroventral and posteroventral secondary setae on meso- and metaTA absent; posterodorsal secondary setae on meso- and metaTA present; mesoTA with less than 7 secondary setae; metaTA with less than 16 secondary setae; secondary setae on U absent. Measurements and ratios that characterize the body shape are shown in Table 9. Secondary leg setation detailed in Table 17.

Remarks. Limbodessus fridaywellensis belongs to the group of stygobitic species characterized by the absence of secondary setae on the urogomphus ( L. challaensis , L. exilis , L. hillviewensis , L. hinkleri , L. leysi , L. masonensis , L. millbilliensis , L. morgani , L. ordinarius , L. pulpa , L. raeae , L. windarraensis , L. yuinmeryensis ) (Fig. 77). Larvae of L. fridaywellensis are easily distinguished from the other species of this group by the following combination of characters: smaller size, lateral margins of the nasale not inflated in dorsal view (Fig. 77), claws relatively longer as compared to tarsus (ratio CL/TA> 0.40), absence of anteroventral secondary setae on the mesotarsus, and absence of posteroventral secondary setae on the tarsus (Fig. 79).