Anchylorhynchus amazonicus Voss, 1943

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 : 21-22

Anchylorhynchus amazonicus Voss, 1943

( Figures 4A , 5A , 6A , 8C , 10 D–F, 19A–B, 20A, 21C)

Ancylorrhynchus amazonicus Voss, 1943:63 (description). Lectotype (designated by Vaurie, 1954): Male; Amazon (Amazones); coll. Kraatz. Deposited in DEI, specimen examined.

Anchylorhynchus amazonicus ; Vaurie, 1954:26 (revision and lectotype designation); Wibmer & O’Brien, 1986:195 (cat.).

Redescription. Male: Body size (length of elytra + pronotum) 4.3–6.0 mm.

Head: Rostrum 1.4–1.8 times as long as pronotum; 1.2–1.4 times wider at apex than at base; integument reddish to dark brown; with seven longitudinal carinae (including a pair along scrobes), distinct throughout their length; scrobes parallel to rostrum; apex covered by microsetae; areas between dorsal carinae covered by wide yellowish scales, distinctively narrower towards the apex of rostrum and directed toward the central carina. Eyes 1.5–1.6 times as high as wide; 0.6–0.9 times more separated above than below. Head with brown integument, similar to or lighter than rostrum; entirely covered by yellow scales directed to the inter-ocular fovea. Antennae with scape straight, clearly not reaching the anterior eye margin; funicle: antennomere I only slightly wider than II, II about as long as I and about 1.5 times as long as III; VI longer than wide and narrower than club; club about as long as the antennomeres VI–V of the funicle. Left mandible straight at outer margin; with one dorsal seta; outer tooth not forming a sharp angle, with somewhat blunt apex; inner tooth well-developed; molar region slightly concave. Left maxilla with stipes moderately elongate, glabrous or with a long ventral seta; galeo-lacinial complex extending beyond apex of palpomere I; palpiger with elongate vental region, dorsal region forming an abtuse angle at base; palpomere I with three apical setae, apical setae longer than the length of palpomere I; palpomere II approximately as long as palpomere I. Labium with prementum slightly narrower than postmentum, about 1.5 times as wide as long, lateral margins parallel in median region, lobed in lateral-apical region, with two oblique rows of setae in dorsal region; ligula present and about as long as half the length of prementum; palps separated by about half the width of palpomere I; palpomere I longer than wide; palpomere II approximately as long as palpomere III; palpomere III with one lateral seta.

Thorax: Pronotum width at base 1.4–1.7 times pronotum length; base slightly lobed at middle; lateral margins in dorsal view subparallel at base and regularly curved to apex, with a subtle apical constriction; integument brown, similar to head; entirely covered by uniformly yellowish scales; scales on basal half of disk directed to the base. Profemur approximately 3 times as long as wide; about 2.5 times as wide as protibia; dorsal margin with curvature about as pronounced as ventral margin; tooth well-defined. Protarsus with tarsomere I about as long as tarsomere III; tarsomeres I and II as long as wide; with short and dense setae on ventral surface and sparse and long setae on sides. Scutellum 0.8–1.3 times longer than wide; integument brown, same color as elytra; scales yellowish. Elytra 1.3–1.6 times wider than pronotum; 1.4–1.5 times longer than wide; 2.6–3.9 times longer than pronotum; humeri rounded; lateral margins subparallel, distinctively wider to only slightly wider at middle; dorsal region with yellowish scales; epipleura without an inflexion on interval IX, covered by scales with same color as disk. Ventral region of thorax integument brown, similar color to dorsal region; scales with color similar or distinctively lighter than dorsal region. Hypomeron covered by sparse scales, most of integument visible; covered by scales with truncated apex narrower or similar to those in pronotum, those next to the coxal cavities larger. Prosternum length 1.1–1.4 times the width of coxae; postocular lobes indistinct, with apical-lateral margin of prothorax regularly curved to slightly sinuate; densely covered by mostly non-overlapping scales narrower than those in pronotum, with acuminate or truncated apex. Metepisternum covered by non-overlapping scales, or overlapping only next to the anterior margin. Metasternum central concavity subtle; with very short setae in the center.

Abdomen: Ventrites III–V covered by recumbent setae or narrow scales. Aedeagus 2–2.5 times as long as wide; about 6 times as long as high; slightly wider at opening; with an acute anterior process; ventral plate thin and barely sclerotized, extending to approximately 0.2 times the length of apodemes. Apodemes about 3 times as long as aedeagus. Endophallus with a pair of L-shaped sclerites anterior to the basal sclerite; with microtrichae of the apical region not organized in bands.

Female: Body size 4.1–4.9 mm. Rostrum 1.5–1.6 times longer than pronotum; width at apex 1.3–1.5 times width at base. Eyes 1.4–1.6 times as high as wide; 0.7–0.9 times more separated above than below. Pronotum 1.5–1.7 times as wide at base as long. Prosternum length 1.0–1.3 times the coxal width. Protarsus without long setae. Scutellum 0.9–1.0 times as long as wide. Elytra 1.3–1.5 times as wide as pronotum; 1.5–1.6 times as long as wide; 3.0–3.7 times as long as pronotum. Ventrites III and IV with posterior retraction not sinuate and restricted to the posterior end of the segment.

Remarks. This species, together with Anchylorhynchus imitator sp. nov., can be distinguished by the metasternal concavity in males weakly delimited and labial palpomere I longer than wide ( Figure 6A ), and by the combination of long rostrum (1.4–1.8 times the length of pronotum), scales directed to the base in the basal half of the pronotum ( Figure 8C ) and convex, round body ( Figures 10 D–F).

It can further be distinguished from A. imitator by a combination of characters, most of which are variable in A. amazonicus but nonoverlapping with A. imitator : eyes less separated above than below in A. amazonicus , with the opposite in A. imitator ; more vividly yellow dorsal scales ( Figures 10 D–F) in contrast to pale yellow scales ( Figure 10G ); elytra wider in the median region in contrast to subparallel; pronotum with lateral margins converging ( Figure 10C ) at base in contrast to subparallel at base ( Figure 8L ).. Scales of A. amazonicus are also more elongate than scales of A. imitator (e. g. Figure 19 ).

Prior to this work, this species was only known from the male lectotype, with imprecise locality in the Amazon. It is not clear if Voss observed more specimens in the type series, but this is the only one remaining. The additional specimens studied were all collected in the Amazon (Pará, Brazil) from a single host plant. Even though they match the type closely, there are a number of characters that are variable in the sample studied, with the holotype standing out. The holotype ( Figure 10D ) has a larger size (pronotum + elytra) than the other specimens (6.0 mm against 4.1–5.1 mm), more vivid yellow coloration and more elongate scales on the ventral surfaces .

Geographical Distribution. This species occurs in the Amazon (Pará, Brazil, Figure 24 )

Host Plants. Syagrus cocoides Mart.

Specimens were collected directly from flowers by R. M. Valente, as indicated in labels.

Examined Specimens. Type Material. NO COUNTRY. No region : Amazonia, no collector, no date (♂ holotype Anchylorhynchus amazonicus DEI)

Other Material. BRAZIL. Pará: Canaã dos Carajás, Projeto Níquel Vermelho , R. M. Valente, 24/VII/2004 (2♀, 2♂ MPEG, 1♀, 1♂ MZSP); 25/VII/2004 (1♀ MPEG) ; 27/XI/2005 (1♂ MPEG, 2♀, 1♂ MZSP); 28/XI/2005 (1♀, 2♂ MPEG, 2♀ MZSP); 30/XI/2005 (4♀, 3♂ MPEG, 2♀ MZSP) .

Figures

FIGURE 4. Left mandibles of species of Anchylorhynchus (ventral view). Scales: 100 µm. A A. amazonicus. B A. trapezicollis. C A. tricarinatus D A. minimus. E A. tremolerasi. F A. variabilis. G A. aegrotus. H A. vanini.

FIGURE 5. Left maxillae of species of Anchylorhynchus (ventral view). Scales: 50 µm. A A. amazonicus. B A. trapezicollis. C A. tricarinatus. D A. minimus. E A. tremolerasi. F A. bucki. G A. aegrotus. H A. vittipennis. I A. variabilis.

FIGURE 6. Labia of species of Anchylorhynchus (dorsal view). Scales: 50 µm. Palp setae illustrated only on left side and lateral-apical setae of prementum only on right side. A A. amazonicus. B A. trapezicollis. C A. minimus. D A. pinocchio. E A. tricarinatus. F A. tremolerasi. G A. bicolor. H A. bucki. I A. aegrotus J A. variabilis.

FIGURE 8. Prothorax of all Anchylorhynchus species. Except for A. parcus, only known from the male holotype, the thorax of a male (left) and a female (right) are shown for each species. Arrows show the direction of scales in each position. Scale: 500 µm. A A. aegrotus. B A. albidus. C A. amazonicus. D A. bicarinatus. E A. bicolor. F A. bucki. G A. burmeisteri. H A. camposi. I A. centrosquamatus (from de Medeiros & Núñez-Avellaneda 2013). J A. chrysomeloides. K A. goiano. L A. imitator. M A. latipes. N A. luteobrunneus (from de Medeiros & Núñez-Avellaneda 2013). O A. minimus. P A. multisquamis. Q A. parcus. R A. pinocchio (from de Medeiros & Núñez-Avellaneda 2013). S A. rectus. T A. trapezicollis U A. tremolerasi V A. tricarinatus W A. vanini X A. variabilis Y A. vittipennis.

FIGURE 10. Habitus of species of Anchylorhynchus. Some images are mirrored in relation to originals. Scales: 1 mm. A A. aegrotus (male) B A. aegrotus (female) C A. albidus D A. amazonicus (male holotype) E–F A. amazonicus (Canaã dos Carajás, Brazil) G A. bicarinatus H–K A. bicolor. Photographs in K provided by Roberta Valente based on specimens loaned from NHMUK. L A. bucki.

FIGURE 19. Male ventrites of species of Anchylorhynchus. Scales: 500 µm. A A. amazonicus, showing recumbent hairs. B A. amazonicus, showing a morph with less elongate scales. C A. imitator, showing that scales on ventrites are never as elongate as in A. amazonicus. D A. goiano. E A. vittipennis. F A. variabilis.

FIGURE 24. Geographical distribution of species of Anchylorhynchus based on specimens examined, excluding suspicious locations as indicated in the main text. The distribution of A. parcus is unknown. A A. aegrotus, A. albidus, A. amazonicus, A. centrosquamatus. B A. bicarinatus, A. bicolor, A. burmeisteri, A. rectus. C A. bucki, A. goiano, A. imitator, A. luteobrunneus. D A. camposi, A. minimus, A. multisquamis, A. tremolerasi. E A. latipes, A. pinocchio, A. trapezicollis, A. vittipennis. F A. chrysomeloides, A. tricarinatus, A. vanini, A. variabilis.