Anchylorhynchus Schoenherr, 1836

De, Bruno A. S. & Vanin, Sergio A., 2020, Systematic revision and morphological phylogenetic analysis of Anchylorhynchus Schoenherr, 1836 (Coleoptera, Curculionidae: Derelomini), Zootaxa 4839 (1), pp. 1-98 : 8-13

publication ID	https://doi.org/ 10.11646/zootaxa.4839.1.1
publication LSID	lsid:zoobank.org:pub:CD765A95-2854-4D92-9EFB-B30B2FF40813
DOI	https://doi.org/10.5281/zenodo.4493901
persistent identifier	https://treatment.plazi.org/id/0389E448-B86E-4B54-FF6F-F8EDFAB2F889
treatment provided by	Plazi
scientific name	Anchylorhynchus Schoenherr, 1836
status

Treatment

Anchylorhynchus Schoenherr 1836:450 (description); Agassiz, 1846:9 (cat.); Agassiz 1848:60 (cat.); Castelnau, 1850:346 (cat.); Lacordaire, 1863:519 (revision, redescription); Sherborn, 1923:300 (cat.); Blackwelder, 1947:827 (cat.); Kuschel,1951:273 (key to genera); Vaurie, 1954:8 (revision and key to species); Viana, 1975:6 (revision and key to species); O’Brien & Wibmer, 1982:96 (cat.); Wibmer & O’Brien, 1986:195 (cat.); Alonso-Zarazaga & Lyal, 1999:77 (cat.); Franz, 2006:275 (phylogeny).

Anchylorhynchus Schoenherr, 1833:20 (nomen nudum).

Anchylorhynchus Dejean, 1833:282 (cat., nomen nudum).

Ancylorhynchus Agassiz, 1846:10 View in CoL (cat., unjustified emendation); Agassiz, 1848:62 (cat.); Sherborn, 1923:303 (cat.).

Ancylorrhynchus Gemminger & Harold, 1871:2545 (cat., unjustified emendation); Bondar, 1940a:855 (cat.) Bondar 1941b:463 (redescription); Voss, 1943:60 (revision and key); Bondar, 1943a:357 (revision and key).

Ancylochynrhus; Faust, 1894:140 (lapsus).

Anchylorrhynchus; Bruch, 1915:418 (lapsus).

Aneylorrhinchus; Bondar, 1943b:95 (lapsus).

Type species: Anchylorhynchus variabilis Gyllenhal , by original designation

Redescription of adults (adapted from Viana, 1975). Head ( Figures 1 View FIGURE 1 A–D, 2): Head small and well introduced into prothorax to the posterior eye margin; sculpted with punctures containing one scale each; depressed between eyes above, with or without distinct fovea; with several transverse striae in ventral region. Eyes ( Figure 1 D View FIGURE 1 ) large, oval, with approximately 250 ommatidia; laterally positioned, 0.5–1.7 times more separated above than below. Rostrum ( Figure 2 View FIGURE 2 ) 0.7–2.0 times as long as prothorax; subrectangular in cross section; only slightly curved; almost always widest near apex; with 2–7 longitudinal carinae in both sexes; with punctures containing one scale each between carinae; with scrobes straight, almost always directed obliquely downward, reaching or almost reaching eye margins. Antennae ( Figure 3 View FIGURE 3 ) long, slender, inserted apically in both sexes; scape reaching or nearly reaching anterior margin of eye, widened apically; funicle with six antennomeres, first always wider than second; antennomeres I–III generally longer than antennomeres IV–VI; club compact, elongate to globose, with three fused but distinct antennomeres. Mandibles ( Figure 4 View FIGURE 4 ) slightly curved downward; with 1–2 acute or truncated teeth; with 1–3 long setae; slightly asymmetric. Maxillae ( Figure 5 View FIGURE 5 ) elongate; palpiger with 1–2 long setae in all species and several short setae in the external ventral margin in most species; palpomere I with two apical setae; palpomere II cylindric, slightly shorter to distinctly longer than palpomere I. Labium ( Figure 6 View FIGURE 6 ) with prementum subquadrate to transverse, with setae in apical-lateral region; palpomere I with one long ventral setae and several short setae.

Thorax: Pronotum ( Figure 7–9 View FIGURE 7 View FIGURE 8 View FIGURE 9 ) transverse, 1.4–2.0 as wide as long; with lateral margins slightly curved and converging distally; with proximal margin straight to sinuate; slightly convex dorsally; with punctures containing one scale each; postocular lobes indistinct to weakly developed, with several short setae along the margin; with sides rounded or forming an acute to obtuse angle with the hypomeron. Scutellum small; transverse to oblong; covered by scales. Elytra ( Figures 10–14 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14 ) wide; one to two times as wide as the pronotum; with sinuate to straight proximal margin; with lateral margins subparallel to widest towards the middle; with distal margin rounded; convex and slightly declined distally; with 10 punctuated striae, each puncture containing one scale. Prosternum ( Figures 9 View FIGURE 9 , 15 View FIGURE 15 ) wide, 0.7–1.7 as long as the coxal width; covered by scales or hairs; coxal cavities contiguous; prosternal process small and triangular; proximal margin bisinuate; distal margin strongly to moderately concave; with a distinct transverse ridge near the distal margin. Mesosternum ( Figure 16 View FIGURE 16 ) wide and short; coxal cavities well separated; mesoepimera and mesoepisterna covered by scales and well delimited. Metasternum ( Figure 17 View FIGURE 17 ) wide and long; coxal cavities well separated; metaepisterna long and narrow, covered by scales. Legs ( Figures 15 View FIGURE 15 , 17–18 View FIGURE 17 View FIGURE 18 ) with procoxae globose, projected and contiguous ( Figure 15 View FIGURE 15 ); mesocoxae globose ( Figure 17 View FIGURE 17 ); metacoxae oblong and transverse ( Figure 17 View FIGURE 17 ); femora clavate in the middle, with a small tooth in the middle of the internal margin ( Figure 18 View FIGURE 18 ); tibiae slightly shorter than femora, laterally flattened, with a small apical tooth usually hidden by hairs ( Figure 18 View FIGURE 18 ), protibiae slightly curved and meso- and metatibiae almost straight; tarsi shorter than the tibiae, densely covered by hairs underneath; claws small, simple and divergent ( Figure 18 View FIGURE 18 ).

Abdomen ( Figures 19–23 View FIGURE 19 View FIGURE 20 View FIGURE 21 View FIGURE 22 View FIGURE 23 ): with five ventrites, the first two fused and the remainder free; with ventrites III–IV much shorter than the others ( Figures 19–20 View FIGURE 19 View FIGURE 20 ). Pygidium covered ( Figures 10–14 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14 ). Male genitalia ( Figures 21–23 View FIGURE 21 View FIGURE 22 View FIGURE 23 ) with spiculum gastrale with asymmetric furcal arms; tegmen delicate; aedeagus 1.7–3.7 times as long as wide, moderately curved, with a sclerotized ventral region extending beyond the insertion of the apodemes; apodemes 1.3–3.1 times longer than the aedeagus; endophallus with microtrichae only in the proximal region and with a proximal complex, laterally symmetric sclerite.

Sexual Dimorphism: males bear denser hairs on tarsi, metasterum and ventrites and a metasternal concavity that may reach the first ventrite ( Figure 19 View FIGURE 19 ). In some species, males are also larger than females. Females have distally narrower abdomens, with ventrites III–IV moderately to strongly retracted ( Figure 20 View FIGURE 20 ). Males bear an elytro-tergal stridulatory apparatus ( Lyal & King 1996), and stridulate when mating or when disturbed. Unlike most Curculionidae with long rostrum, there is generally no sexual dimorphism in the rostrum length, sculpture or position of antennal insertions. The exception is Anchylorhynchus pinocchio de Medeiros & Núñez-Avellaneda , in which males bear a longer rostrum with more distal antennal insertions.

Redescription of immatures (adapt ed fr om Medeiros et al. 2014). Immatures of Anchylorhynchus have only been studied in detail for A. eriospathae (here placed as Anchylorhynchus tremolerasi Hustache , see below) and a detailed description of eggs, larvae, pupae, including images and information on development for this species is available from de Medeiros et al. (2014). Other species with larvae observed by us superficially resemble A. eriospathae , including Anchylorhynchus aegrotus Fahraeus , A. bicarinatus , Anchylorhynchus trapezicollis Hustache and A. variabilis .

Larva (2 nd– 4 th instars): Subcylindrical, C-shaped, weakly curved dorso-ventrally. Head hypognathous, gula absent. Four pairs of frontal setae and two pairs of clypeal setae present. Mandibles cuneiform, with one large apical tooth and one small median tooth. Ventropedal lobe setae of thorax and abdomen short.

Larva (1 st instar): Body strongly flattened. Head prognathous, about one fourth of body length, gula present. Three pairs of frontal setae present. Clypeal setae absent. Mandibles falciform with serrate retinaculum. Ventropedal lobe setae of thorax and abdomen very elongate, about as wide as prothorax width.

Egg: flat; elliptic; flexible; slightly curved; translucent when recently laid.

Diagnosis. Adults of Anchylorhynchus can be distinguished from other Derelomini by the following characters: convex, rounded body (other derelomines are more elongate); six antennomeres in the funicle (seven in other genera); apical antennal insertions in both sexes (variable and sexually dimorphic in other genera); body densely covered by yellow to black flattened scales (usually not as dense in other genera); complex barrel-shaped sclerite in endophallus (absent in other genera). Although not thoroughly evaluated here, Anchylorhynchus seems to be the only Derelomini with elytro-tergal stridulation ( Lyal & King 1996).

The flattened eggs of Anchylorhynchus are quite distinctive when compared to weevil eggs and most beetle eggs, which are usually globose and nearly spherical ( Church et al. 2019a; b). Flattened first-instar larvae bearing falcate mandibles and very long setae in the abdominal and thoracic ventropedal lobes are also diagnostic of Anchylorhynchus .

Distribution and Host Plants. Species of Anchylorhynchus are found from Argentina to Panama, in wet forests, seasonally dry forests, savannas and grasslands ( Figure 24 View FIGURE 24 ). They are associated with flowers of palm species in the genera Syagrus , Butia , Euterpe and Oenocarpus ( Table 1). See introduction for details on natural history.

Here follow descriptions of the species of Anchylorhynchus , sorted in alphabetical order. In all cases, we first describe males and then only sexually dimorphic traits for females. A table with data for all specimens observed is available as supplementary file 1 and raw measurements for the subset used for measurements as supplementary file 2. Both files are available in the github repository https://github.com/brunoasm/revision_anchylorhynchus.