Anchylorhynchus imitator, De & Vanin, 2020

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 : 36-38

Anchylorhynchus imitator sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:55D3BA2F-BD11-4E8C-819A-C591DDD06E06

( Figures 8L , 11G , 19C , 22C )

Holotype: Male ; Cuiabá, Mato Grosso, Brazil (S15.29377, W55.96375); 19-X-2009; Medeiros, B.A.S col.; in flowers of “ Syagrus comosa ”. Deposited in MZSP.

Description. Male: Body size (length of elytra + pronotum) 4.0– 5.6 mm.

Head: Rostrum 1.3–1.6 times as long as pronotum; 1.3–1.4 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, scales directed toward the central carina. Eyes 1.6–1.6 times as high as wide; 1.2 times more separated above than below. Head integument brown, sometimes lighter than rostrum; entirely covered by yellow scales directed to the inter-ocular fovea. Antennae with scape straight, clearly not reaching anterior eye margin; funicle: antennomere I of funicle only slightly wider than II, II about as long as III and about 1.5 times as long as III, VI longer than wide and narrower than club; club about as long as the antennomeres V–VI of 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; galeo-lacinial complex extending beyond the apex of palpomere I; palpiger with elongate vental region, dorsal region with an abtuse angle at base; palpomere I with three apical setae longer than the length of palpomere I. Labium 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 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 two lateral setae.

Thorax: Pronotum width at base 1.4–1.6 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 the disk with basal half directed to the base. Profemur approximately 3 times as long as wide; dorsal margin with curvature about as pronounced as ventral margin; tooth well-defined; about 2.5 times as wide as protibia. Protarsus tarsomere I about as long as tarsomere III; tarsomeres I and II as long as wide; with short and dense setae on the ventral surface and sparse and long setae on the sides. Scutellum 0.8–1.0 times longer than wide; integument brown, the same color as elytra; scales yellowish. Elytra 1.2–1.4 times wider than pronotum; 1.4–1.5 times longer than wide; 2.4–2.8 times longer than pronotum; humeri with a well-defined angle; lateral margins subparallel, only slightly wider at middle; dorsal region with yellowish scales; epipleura without a marked inflexion on interval IX, covered by yellow scales with the same color as disk. Ventral region oh thorax integument brown, similar to dorsal region; scales yellowish, sometimes slightly lighter than those in dorsal region. Hypomeron densely covered by mostly non-overlapping scales with truncated apex, similar in shape to those in pronotum; scales next to coxal cavities larger. Prosternum length 1.2–1.4 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 with acuminate or truncated apex; scales may be wider or narrower than those in pronotum. Metepisternum covered by non-overlapping scales, or overlapping only next to the anterior margin. Metasternum central concavity subtle; covered by scales in the center.

Abdomen: Ventrites III–V covered by 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; microtrichae of the apical region not organized in bands.

Female: Body size 4.6–5.3 mm. Rostrum 1.5–1.6 times longer than pronotum. Eyes 1.6 times as high as wide; 1.1 times more separated above than below. Pronotum 1.5–1.6 times as wide at base as long. Prosternum length 1.2–1.3 times the coxal width. Protarsus without long setae; Scutellum 0.7–0.9 times as long as wide. Elytra 1.4–1.8 times as wide as pronotum; 1.2–1.4 times as long as wide; 3.1–3.2 times as long as pronotum. Ventrites III and IV with posterior retraction not sinuate and restricted to the posterior end of the segment.

Etymology. Imitator means mimic, named after the similarity between this species and Anchylorhynchus amazonicus .

Remarks. This species, together with A. amazonicus , 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).

This species is very similar to Anchylorhynchus amazonicus . The two species are certainly closely related, with very similar male genitalia ( Figures 21C , 22C ). However, they can be distinguished by a combination of characters: eyes more separated above than below in A. imitator , with the opposite in A. amazonicus ; the ventral scales of A. imitator (e. g. Figure 19C ) are wider than those of A. amazonicus (e. g. Figure 19B ); the dorsal scales are pale yellow ( Figure 11G ) instead of a brighter yellow ( Figure 10 D–F); elytra are not widened towards the middle and the pronotal margins are subparallel at base in this species ( Figure 8L ), while typically converging at base in A. amazonicus ( Figure 8C ).

Geographical Distribution. The species is only known from the region of the Chapada dos Guimarães, Mato Grosso, Brazil ( Figure 24 ), but one of its host plants ( Syagrus comosa ) is widespread throughout savannas in central Brazil (cerrado). We did not find this species by sampling flowers of one individual of Syagrus comosa in Brasilia National Park, Distrito Federal, Brazil.

Host Plants. Syagrus comosa (Mart.) Mart. in Orbigny (vouchers SPF B.A.S. Medeiros 28-30,353) and Syagrus guimaraesensis Noblick & Lorenzi (voucher SPF B.A.S. Medeiros 359).

We collected all specimens directly from flowers of the sympatric palms Syagrus comosa and Syagrus guimaraesensis .

Examined Specimens. Type Material. BRAZIL. Mato Grosso: Cuiabá, B. A. S. Medeiros, 19/X/2009 (♂ holotype Anchylorhynchus imitator MZSP); Chapada dos Guimarães, B. A. S. Medeiros, 20/X/2009 (3♀ paratypes Anchylorhynchus imitator MZSP, 2♂ paratypes Anchylorhynchus imitator MZSP); Cuiabá, B. A. S. Medeiros, 19/ X/2009 (1♀ paratype Anchylorhynchus imitator MPEG, 1♂ paratype Anchylorhynchus imitator MPEG, 7♀ para-types Anchylorhynchus imitator MZSP, 1♂ paratype Anchylorhynchus imitator MZSP)

Other Material. BRAZIL. Mato Grosso: Chapada dos Guimarães, B. A. S. Medeiros & E. P. Antunes, 01/ XII/2014 (11 sex undetermined MZSP) .

Figures

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 11. Habitus of species of Anchylorhynchus (continued). Some images are mirrored in relation to originals. Scales: 1 mm. A–B A. burmeisteri. C A. camposi. D A. centrosquamatus (from de Medeiros & Núñez-Avellaneda 2013). E A. chrysomeloides. F A. goiano. G A. imitator. H A. latipes I–K A. luteobrunneus (from de Medeiros & Núñez-Avellaneda 2013). L A. minimus.

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 21. Male genitalia of species of Anchylorhynchus. A. parcus is known only from the holotype, which was not dissected. Scales: 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 (reproduced from de Medeiros & Núñez-Avellaneda, 2013).

FIGURE 22. Male genitalia of species of Anchylorhynchus (continued). Scales: 500 µm. A A. chrysomeloides B A. goiano C A. imitator D A. latipes E A. luteobrunneus (reproduced from de Medeiros & Núñez-Avellaneda, 2013). F A. minimus. G A. multisquamis. H A. pinocchio (reproduced from de Medeiros & Núñez-Avellaneda, 2013). I A. rectus.

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.