Limbodessus nambiensis Watts & Humphreys, 2006

Michat, Mariano C., Alarie, Yves & Watts, Chris H. S., 2012, 3584, Zootaxa 3584 (1), pp. 1-110 : 69

Limbodessus nambiensis Watts & Humphreys, 2006

( Figs 162 –175)

Source of material. One specimen of instar I and one of instar II were used for the description ( Table 1). Larvae were collected at the following localities: Australia, Carey palaeovalley, Nambi calcrete, MEB site 106, BES 10314, 28.23974S, 121.83632E, 21–III–2004, coll. W. F. Humphreys and S. J. B. Cooper; Nambi calcrete, MEB site 105, BES 10316, 28.24039S, 121.83721E, 21–III–2004, coll. W. F. Humphreys and S. J. B. Cooper. The larvae studied were determined by comparing the sequence of a fragment of the CO1 gene with that of a known adult .

Diagnosis (instar II). Medium-sized species (instar II: HL 0.45–0.85 mm); head 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 moderately reduced (instar II: HW/OCW 0.80–2.10); occipital suture present; lateral margins of parietal straight; secondary spiniform setae on lateral margins of parietal numerous; seta AN2 present; distal half of MN broad; setae LA3, LA4, LA5 and LA8 hair-like; secondary setae on U present.

Instar I ( Figs 162 –175). Head ( Figs 162–170 ). Cephalic capsule not strongly elongate (HL/HW less than 1.55); seta PA3 inserted far from setae PA1 and PA2; A3 less than 2.15 times longer than A1; A3 more than 2.25 times longer than A2; MP2 less than 1.45 times longer than MP1; MP2 1.95–2.65 times longer than MP3; LP2 less than 1.30 times longer than LP1. Legs (Figs 171–172). L3 less than 2.85 times longer than HW. Abdomen (Figs 173–175). U 3.60–3.70 times longer than LAS; U less than 2.35 times longer than HW; U1 more than 1.45 times longer than U2. Chaetotaxy. Frontoclypeus with 12 lamellae clypeales; additional setae on U absent. Measurements and ratios that characterize the body shape are shown in Table 3.

Instar II. Head. A3 less than 2.50 times longer than A1; A4 less than 0.70 times as long as A3; MN less than 4.70 times longer than broad; MP2 less than 1.05 times longer than MP1; MP2 2.10–2.95 times longer than MP3; LP2 less than 0.90 times as long as LP1. Abdomen. U 3.00–4.00 times longer than LAS; U less than 2.15 times longer than HW; U1 less than 1.45 times longer than U2. Chaetotaxy. Anteroventral margin of nasale with 36 lamellae clypeales distributed in a single row; secondary setae on U present. Measurements and ratios that characterize the body shape are shown in Table 6.

Instar III. Not available.

Remarks. The description of L. nambiensis is based on one well preserved instar I and one instar II in which the legs are lacking. For this reason, morphometric and chaetotaxic characters could not be evaluated. The absence of instar III specimens hampers the comparison with the other species described here, particularly regarding the chaetotaxic characters. Limbodessus nambiensis belongs to the group of stygobitic species characterized by the presence of secondary setae on the urogomphus ( L. barwidgeeensis , L. bigbellensis , L. cooperi , L. eberhardi , L. macrohinkleri , L. raesideensis , L. yandalensis ), and within this group it can be distinguished by the following combination of characters: smaller size, head subpentagonal, occipital suture present, and occipital foramen moderately reduced.

Figures

FIGURES 162–170. Limbodessus nambiensis, first-instar larva. 162, cephalic capsule, dorsal aspect; 163, cephalic capsule,