Undarobius howarthi Escalona & Oberprieler, 2021

Escalona, Hermes E. & Oberprieler, Rolf G., 2021, Undarobius, a new genus of cavernicolous weevils (Curculionidae: Entiminae Leptopiini) from the Undara Lava Caves in north-eastern Australia, with an overview of anophthalmic and microphthalmic Australian Curculionidae, Zootaxa 5023 (2), pp. 207-222 : 211

Undarobius howarthi Escalona & Oberprieler sp. n.

( Figs. 9–10, 12, 14–35 ) http://zoobank.org/ urn:lsid:zoobank.org:act:E53C4BEB-FA92-4141-AD93-CB3405870D4A

Diagnosis. Body length 4.0– 5.5 mm. Elytral setae short, apically widened and truncate. Punctures on pronotum and elytra fine, sparse, distance between punctures greater than puncture sizes. Body 1.5 × longer than wide, rostrum 2.1 × longer than wide. Prothorax and elytra 1 × and 1.1 × as long as wide, respectively. Spermatheca as in Fig. 35 .

Description. General appearance. Body length 4.0– 5.5 mm, 1.5 × longer than wide. Squamae sparse on pronotal and elytral discs but denser laterally, easily abraded ( Figs. 9–10 ); pronotal and elytral setae short, apically widened and truncate. Head. Rostrum 2.1 × longer than wide and 1.6 × longer than head in lateral view ( Fig. 19 ), oval in cross-section. Prementum as in Fig. 20 . Position of eyes indicated by small glabrous area ( Fig. 19 ) and in cleared specimens by small mark (probably remnant of an ommatidium). Antennae. Scapes 0.8 × shorter than funicle and club. Funicles with segment 1 longer than 3. Thorax. Pronotum as long as wide, with sparse fine punctures, distance between them larger than puncture size. Hypomera behind procoxae 1.5 × longer than coxal width. Elytra 1.1 × as long as wide, disc barely convex, setae short, apically widened and truncate. Legs. Femora ( Figs. 28–30 ) inflated in distal third. Metatibial apex with reduced or well developed mucro. Tarsi with segment 1 shorter than 3–5. Abdomen as in Fig. 27 . Male genitalia. Penis as in Figs. 31–32 . Female genitalia. Spermatheca as in Fig. 35 .

Material examined (14 ex.). HOLOTYPE, ♂: QLD Undara NP / Bayliss Cave / 700m 15 Jun 1985 / F.G. Howarth, F.D. Stone / J. Bresnan BY66 // On cornflakes bait / Cave sections The Wall & / Duckunder // HOLOTYPE / Undarobius howarthi / Escalona & Oberprieler 2021 ( ANIC ). PARATYPES: 2 ex. (1 ♀), same data as holotype ( ANIC ); 6 ex. (2 ♂♂) “QLD 18º 13’S x 144º 36’E / Bayliss Cave Undara NP / 12 Jun 1986 / F. Howarth & S. Robson” ( QM); 5 ex. (1 ♂, 1 ♀) “QLD 18º 13’S x 144º 36’E / Bayliss Cave Undara NP / 31 May 1986 / F. Howarth & D. Irwin” ( QM); 1 ♂, “QLD Undara NP / Bayliss Cave / 22 May 1985 / F.D. Stone, F.G. Howarth / D. Irwin BY8B / [dissected]” ( ANIC ); all labelled “ PARATYPE / Undarobius howarthi / Escalona & Oberprieler 2021”.

Derivation of name. The species is named for the biospeleologist Francis G. Howarth (Hawaii Biological Survey, Hawaii, U.S.A.), one of the discoverers of this exceptional cave inhabitant as well as of other animals of the Undara Lava Cave system .

Comments. All specimens were collected in a deep section of Bayliss Cave known as The Wall, which is about 650 m from the entrance and part of the “stagnant-air” or “bad-air” zone as it has a high concentration of carbon dioxide ( Howarth 1988). The weevils were collected at bait put out on the cave floor, the holotype and one paratype at cornflakes and the others at pieces of sweet potato tuber ( Ipomoea batatas ) (see Fig. 2D in Howarth & Stone 1990 and Fig. 11 in Stone 2010). Bayliss Cave contains abundant organic material, mainly bat guano and root tresses ( Howarth & Stone 1990). Stone et al. (2012) considered these weevils to be part of the cave tree-root community, functioning as primary consumers of the roots penetrating into the cave from above (identified as Brachychiton , Eucalyptus and Ficus ). As entimine larvae generally feed on roots in the soil, it is possible that those of U. howarthi do so as well, although they may also live among the root tresses above the cave floor or even in the roof of the caves.

Figures

FIGURES 9–16. Undarobius habitus and mouthparts. 9–10, 12—U. howarthi sp. n. (SL 3.8 mm, ♂) 9–10: dorsal, 12: lateral aspect; 11, 13—U. irvini sp. n. (SL 3.8 mm, ♀) 11: dorsal, 13: lateral aspect; 14– 16—U. howarthi sp. n. ♀, mouthparts, 14: labium, ventral view, 15: left mandible, dorsal view, 16: right maxilla, ventral view.

FIGURES 17–25. Undarobius howarthi sp. n., ♂, structural details. 17—head, dorsal view; 18—head, ventral view; 19—head, lateral view; 20—mouthparts, ventral view; 21—apex of rostrum, dorsal view; 22—left antenna, dorsal view; 23—prothorax, ventral view; 24—prothorax, dorsal view; 25—elytra, dorsal view.

FIGURES 26–36. Undarobius species, structural details. 26–34 U. howarthi sp. n., 26—pterothorax and elytra, ventral view; 27—ventrites, ♂, ventral view; 28—foreleg; 29—middle leg; 30—hindleg; 31—penis, dorsal view; 32—penis, lateral view; 33—sternite VIII, ♀, ventral view; 34—ovipositor, ventral view; 35—spermatheca; 36—U. irvini sp. n., spermatheca.

FIGURES 1–8. Selected Australian anophthalmic and microphthalmic Curculionidae. 1—Hexonomys reginalis Kuschel (SL 0.9 mm); 2—Myrtonymus moorei Kuschel (SL 0.9 mm); 3—Notiomimetes pascoei Wollaston (SL 1.3 mm); 4—Wollastonicis minutus Lea (SL 1.6 mm); 5—Tasmanica sp. (SL 1.7 mm, Tas, Kettering); 6—Listroderini undetermined genus (SL 3.8 mm, SA, Kelly Hill Cave, Kangaroo Island, ANIC); 7—Cryptorhynchini undetermined genus (SL 2.7 mm, WA, Mt. Trafalgar, ANIC); 8—Halorhynchus caecus Wollaston (SL 1.6 mm).