Anchylorhynchus rectus, 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 : 47-48

Anchylorhynchus rectus sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:33ABDBC7-4016-4A09-BC4F-1C43D84FCA0E

( Figures 8S , 12E , 22I )

Holotype: Male ; Serra do Cipó, Jaboticatubas, Minas Gerais, Brazil; 6–10-X-1975; Vanin col.; in flowers of “ Syagrus ”. Deposited in MZSP.

Description. Male: Body size (length of elytra + pronotum) 5.3–6.7 mm.

Head: Rostrum 1.3–1.4 times as long as pronotum; 1.4–1.7 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, directed toward the central carina. Eyes 1.5 times as high as wide; 0.8 times more separated above than below. Head reddish to dark brown, similar to 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 only slightly wider than II, II about as long as I and about 2 times as long as III, VI as wide as long and narrower than club; club about as long as the antennomeres V–VI of the funicle. Left mandible straight at outer margin; with one dorsal seta; outer tooth forming a sharp angle with the mandible margin, with rounded apex; inner tooth well-developed; molar region slightly concave. Left maxilla with stipes moderately elongate, with a long ventral seta; galeo-lacinial complex extending beyond the apex of palpomere I; palpiger with elongate ventral region, dorsal region with an obtuse angle at base; palpomere I with three apical setae longer than the length of palpomere I; palpomere II approximately as long as palpomere I. Labium prementum slightly narrower than postmentum, about 1.5 times as wide as long, lateral margins parallel in median region, lobed in lateralapical 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 approximately as long as wide; palpomere II approximately as long as palpomere III; palpomere III with two lateral setae.

Thorax: Pronotum width at base 1.5–1.5 times pronotum length; base slightly lobed at middle; lateral margins in dorsal view parallel 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; dorsal margin with curvature about as pronounced as ventral margin; tooth well-defined; about 2.5 times as wide as protibia. Protarsus with tarsomere I distinctively longer than tarsomere III; tarsomeres I and II slightly wider than long; with short and dense setae on the ventral surface and sparse and long setae on the sides. Scutellum 0.7–0.9 times longer than wide; integument brown, similar to elytra; scales yellowish. Elytra 1.1–1.2 times wider than pronotum; 1.4–1.6 times longer than wide; 2.5–2.8 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 similar to disk. Ventral region of thorax integument brown, similar to dorsal region; scales yellow, similar to or slightly lighter than pronotum. Hypomeron covered by sparse scales with truncated apex, similar in shape to those in pronotum; scales next to coxal cavities larger. Prosternum length 1.5–1.7 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, narrower than those in pronotum. Metepisternum covered by non-overlapping scales, or overlapping only next to the anterior margin. Metasternum without a central concavity; with long setae in the center.

Abdomen: Ventrites III–V covered by narrow scales. Aedeagus 2–2.5 times as long as wide; about 7 times as long as high; slightly wider at opening; with an acute anterior process; ventral plate thin and barely sclerotized, extending to approximately half the length of apodemes. Apodemes about 2.5 times as long as aedeagus. Endophallus with a pair of L-shaped sclerites anterior to basal sclerite; microtrichae of the apical region not organized in bands.

Female: Body size 4.8–6.0 mm. Rostrum 1.4–1.5 times longer than pronotum; width at apex 1.4–1.5 times width at base. Eyes not measured. Pronotum 1.5–1.6 times as wide at base as long; lateral margins in dorsal view parallel to subparallel at based and evenly curved to apex. Prosternum length 1.4–1.4 times the coxal width. Protarsus tarsomeres I–II as long as wide; without long setae; Scutellum 0.8–1.1 times as long as wide. Elytra 1.2–1.3 times as wide as pronotum; 1.6–1.7 times as long as wide; 3.0–3.2 times as long as pronotum. Ventrites III and IV with posterior retraction not sinuate and restricted to the posterior end of the segment.

Etymology. This species is named after the elongate form, with right angles at humeri and parallel elytral margins ( rectus means straight).

Remarks. This species has been previously identified as Anchylorhynchus amazonicus in collections, which is the result of following the key in Vaurie (1954), and also as Anchylorhynchus camposi , to which it is similar in general appearance. It shares with both species and with A. imitator the scales on the disk of the pronotum directed towards the base. It can be distinguished from A. camposi by the longer rostrum (about 1.5 times the length of the pronotum, compared with 1.1–1.3 in A. camposi ), the prosternal scales larger when close to coxal cavities and the sexual dimorphism in the protarsi, with long setae on the sides of males. It can be distinguished from A. amazonicus and A. imitator by the same characters, in addition to more sparse vestiture in the ventral region and more elongate body, not widened in the middle and with right-angled humeri.

Geographical Distribution. This species is distributed in savannas (cerrado) in the Brazilian states of Minas Gerais, Bahia and Goiás ( Figure 24 ).

Host Plants. Syagrus glaucescens Glaz. ex Becc. (vouchers SPF B.A.S. Medeiros 27, 96), Syagrus gouveiana Noblick & Lorenzi (voucher SPF B. A. S. Medeiros 92) and Syagrus itacambirana Noblick & Lorenzi (voucher SPF B. A. S. Medeiros 86).

During the collection of the type series, the host palm was not identified. In a recent visit we confirmed that this species was only found in Syagrus glaucescens at that locality, with the other abundant Syagrus species ( Syagrus pleioclada ) only hosting A. camposi . Sampling of two other species of Syagrus in Minas Gerais yielded specimens of A. rectus . Additional hosts are likely, since the known host plants do not occur in the westernmost localities for this species ( Noblick 2017).

Examined Specimens. Type Material. BRAZIL. Minas Gerais: Jaboticatubas, Serra do Cipó , S. A. Vanin, 06–10/X/1975 (♂ holotype Anchylorhynchus rectus MZSP, 6♀, 3♂ paratypes Anchylorhynchus rectus MZSP)

Other Material. BRAZIL. Bahia: Barreiras , Sebastião Laroca, 10/ VI /1964 (1♂ DZUP) . Goiás: Cabeceiras , Exp. Dep. Zool., 24–27/X/1964 (1♀ MZSP) . Minas Gerais: Couto de Magalhães de Minas , B. A. S. Medeiros & L. H. M. Fonseca, 21/XI/2013 (3 sex undetermined MZSP) ; Gouveia, B. A. S. Medeiros & L. H. M. Fonseca, 20/ XI/2013 (2 sex undetermined MZSP); 21/XI/2013 (8 sex undetermined MZSP) ; Itacambira, B. A. S. Medeiros & L. H. M. Fonseca, 19/XI/2013 (3 sex undetermined MZSP) ; Santana do Riacho, Serra do Cipó , B. A. S. Medeiros, 17/IV/2009 (1♀ MZSP) .

Figures

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 12. Habitus of species of Anchylorhynchus (continued). Some images are mirrored in relation to originals. Scales: 1 mm. A A. multisquamis. B A. pinocchio (male). C A. pinocchio (female). D A. parcus (male holotype). Photographed by Johannes Bergsten © 2017 Naturhistoriska riksmuseet. Background removed from original photo, light levels and contrast adjusted. Made available by the Swedish Museum of Natural History under CC-BY 4.0 international license. E A. rectus. F A. trapezicollis. G–L A. tremolerasi.

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.