Palaechthina Brinck, 1948, 2013

Morrone, Juan J., 2013, The subtribes and genera of the tribe Listroderini (Coleoptera, Curculionidae, Cyclominae): Phylogenetic analysis with systematic and biogeographical accounts, ZooKeys 273, pp. 15-71 : 26

Subtribe Palaechthina Brinck, 1948 stat. n.

Palaechtini Brinck, 1948:

43; Bouchard et al. 2011: 603 (incorrect original stem formation, not in prevailing usage).

Type genus.

Palaechthus C. O. Waterhouse, 1884 (by original designation, as Palaechtus , incorrect subsequent spelling).

Diagnosis.

Rostrum slender, as long as or longer than pronotum (except for some species of Listronotus where the rostrum is shorter than pronotum); scrobes long, deep, sharply bordered, reaching eyes; scape usually short (not reaching anterior margin of eye when resting in scrobe); pronotum usually subclyndrical or subcircular; elytra oblong-oval to elongate-oval.

Biology.

Most of the species of Palaechthina are associated to aquatic or semiaquatic plants, being found in wet or damp conditions ( May 1970; O’Brien 1977, 1981; Marvaldi 1994; Morrone and O’Brien 2000). In contrast with the remaining Listroderini , larvae usually lead a more endophytic way of life inside the stems of several aquatic plants (Oberprieler, in press).

Included taxa.

This subtribe includes the genera Anorthorhinus , Gunodes , Haversiella , Inaccodes , Listronotus , Neopachytychius , Palaechthus , Palaechtodes , Steriphus and Tristanodes . Anorthorhinus and Steriphus are Australian; Gunodes , Inaccodes , Palaechthus , Palaechtodes and Tristanodes are distributed in the Tristan da Cunha-Gough islands; and the remaining three genera are found in the Americas: Haversiella and Neopachytychius in South America and Listronotus has a disjunct distribution in South and North America.

Key to the genera of Palaechthina

1	Funicular segment 1 subequal to or shorter than 2	2
-	Funicular segment 1 longer than 2	6
2	Elytra with intervals convex; North and South America	Listronotus ( Fig. 21 )
-	Elytra with intervals flat; Tristan da Cunha-Gough islands	3
3	Small to very small (3.7-6.5 mm)	Tristanodes
-	Medium-sized to large (7.0-12.0 mm)	4
4	Vestiture of subcircular scales and setae; pronotum subcircular; elytra oblong-oval	Gunodes
-	Vestiture of seta-like scales and setae; pronotum subtrapezoidal or subclyndrical; elytra elongate-oval	5
5	Large (11.0-12.0 mm); rostral dorsal carinae absent; pronotum subtrapezoidal	Palaechthus
-	Medium-sized (7.0-7.5 mm); rostral dorsal carinae present; pronotum subclyndrical	Palaechtodes
6	Scape long (surpassing posterior margin of eye when resting in scrobe); elytra with anteapical tubercle	Steriphus
-	Scape short (not reaching anterior margin of eye when resting in scrobe); elytra lacking anteapical tubercle	7
7	Vestiture of seta-like scales and setae; Australia and Tristan da Cunha-Gough islands	8
-	Vestiture of subcircular scales ans setae; South America	9
8	Funicular segments 3-6 elongate; club fusiform; pronotum subclyndrical; elytra with intervals convex; Australia	Anorthorhinus
-	Funicular segments 3-6 globose; club inflated; pronotum subcircular; elytra with intervals flat; Tristan da Cunha-Gough islands	Inaccodes
9	Vestiture of subcircular scales and setae; rostral dorsal carinae present; mandibles long and narrow; antennal insertion distal; postocular lobes slightly developed; elytra oblong-oval; tibiae with spurs	Neopachytychius ( Fig. 22 )
-	Vestiture of subcircular scales only; rostral dorsal carinae absent; mandibles robust; antennal insertion at the middle of the rostrum; postocular lobes absent; elytra elongate-oval; tibiae lacking spurs	Haversiella ( Fig. 20 )

Figures

Figures 18 - 26. Habitus of representative Listroderini. 18 Adioristidius hirsutus 19 Puranius nigrinus 20 Haversiella albolimbata 21 Listronotus bosqi 22 Neopachytychius squamosus 23 Falklandiellus suffodens 24 Falklandiopsis magellanica 25 Falklandius antarcticus 26 Gromilus veneris.