Limbodessus fridaywellensis
Creators: name: Michat, Mariano C.
name: Alarie, Yves
name: Watts, Chris H. S.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Dytiscidae
Limbodessus
Limbodessus fridaywellensis

description: <i>Limbodessus fridaywellensis</i> (Watts &amp; Humphreys, 2001) (Figs 77–80) <b>Source of material.</b> One specimen of instar III was used for the description (Table 1). Larva was collected in association with adults at the following locality: <b>Australia, Raeside palaeovalley</b>, Depot Springs calcrete, site 425, BES 8414, 28.05S, 120.03917E, 28–VI–2000, coll. W. F. Humphreys and S. Hinze. <b>Diagnosis (instar III).</b> 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). <b>Instar I.</b> Not available. <b>Instar II.</b> Not available. <b>Instar III</b> (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. <b>Remarks.</b> <i>Limbodessus fridaywellensis</i> belongs to the group of stygobitic species characterized by the absence of secondary setae on the urogomphus (<i>L. challaensis</i>, <i>L. exilis</i>, <i>L. hillviewensis</i>, <i>L. hinkleri</i>, <i>L. leysi</i>, <i>L. masonensis</i>, <i>L. millbilliensis</i>, <i>L. morgani</i>, <i>L. ordinarius</i>, <i>L. pulpa</i>, <i>L. raeae</i>, <i>L. windarraensis</i>, <i>L. yuinmeryensis</i>) (Fig. 77). Larvae of <i>L. fridaywellensis</i> 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&gt; 0.40), absence of anteroventral secondary setae on the mesotarsus, and absence of posteroventral secondary setae on the tarsus (Fig. 79).
description: Published as part of <i>Michat, Mariano C., Alarie, Yves &amp; Watts, Chris H. S., 2012, 3584, pp. 1-110 in Zootaxa 3584 (1)</i> on pages 43-44, DOI: 10.11646/zootaxa.3584.1.1