Anchylorhynchus minimus Bondar, 1950

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 : 41-42

Anchylorhynchus minimus Bondar, 1950

( Figures 3D , 4D , 5D , 6C , 8O , 11L , 18D , 22F )

Ancylorrhynchus minimus Bondar, 1950:466 , Fig. 8 (description). Lectotype (designated by Vaurie, 1954): Female; Corupá, Santa Catarina, Brazil; Maller col. Deposited in AMNH, examined.

Anchylorhynchus minimus ; Vaurie, 1954:20 (revision and lectotype designation); Viana, 1975:19, Figs. 15 e 16 (revision); Wibmer & O’Brien, 1986:196 (cat.).

Redescription. Male: Body size (length of elytra + pronotum) 2.3–3.8 mm.

Head: Rostrum 1.7–1.9 times as long as pronotum; 1.3–1.7 times wider at apex than at base; with integument yellowish 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 1.2–1.3 times as high as wide; 0.7–0.9 times more separated above than below. Head with integument with same color as rostrum; entirely covered by yellow scales directed to the inter-ocular fovea. Antennae with scape straight, barely reaching anterior eye margin; funicle: antennomere I about 1.5 times as wide as II, II longer than I and about 2 times as long as III, VI as wide as long and narrower than club; club about as long as antennomeres IV–VI of the funicle. Left mandible slightly sinuate at outer margin; with one dorsal seta; outer tooth with truncated apex, forming a sharp angle with the mandible margin; inner tooth well-developed; molar region straight. Left maxilla with stipes moderately elongate, with a long ventral seta; galeo-lacinial complex almost reaching the apex of palpomere I; palpiger with ventral region approximately as long as wide, dorsal region with an acute angle at base; palpomere I without apical setae; palpomere II approximately as long as palpomere I. Labium with prementum slightly narrower than postmentum, almost as long as wide, lateral margins parallel in median region, with a right angle in lateral-apical region, with a median longitudinal row of long setae in dorsal region; ligula inconspicuous; palps separated by less than half the width of palpomere I; palpomere I transverse; palpomere II approximately as long as palpomere III; palpomere III with one lateral seta.

Thorax: Pronotum width at base 1.7–1.9 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 disk directed to the apex. Profemur approximately 3.5 times as long as wide; dorsal margin with curvature about as pronounced as ventral margin; tooth well-defined; about 3 times as wide as protibia. Protarsus with 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, without sparse and long setae on the sides. Scutellum 0.5–0.8 times longer than wide; integument brown, the same color as elytra; scales yellowish. Elytra 1.5–2.0 times wider than pronotum; 1.1–1.6 times longer than wide; 4.3–4.6 times longer than pronotum; humeri rounded; lateral margins distinctively wider at the middle; dorsal region covered by uniformly yellow scales or with large dark spots on sides from the epipleura to the third interval, interspersed with yellow scales; epipleura without a marked inflexion on interval IX, covered by yellow or dark scales, following the pattern on disk. Ventral region of thorax integument brown, similar to dorsal region; scales pale yellow, distinctively lighter than those in pronotum. Hypomeron covered by sparse scales with truncated apex narrower or similar to those in pronotum; scales next to coxal cavities larger. Prosternum length 0.8–1.1 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 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 recumbent setae. Aedeagus 2–2.5 times as long as wide; about 5 times as long as high; not wider at opening; with a truncated anterior process; ventral plate strongly sclerotized, extending to approximately 0.3 times the length of apodemes. Apodemes about 1.5 times as long as aedeagus. Endophallus with two pairs of membranous pockets containing microtrichae next to the basal sclerite and with a membranous and slightly sclerotized area anterior to basal sclerite; microtrichae of the apical region not organized in bands.

Female: Body size 2.7–3.7 mm. Rostrum 1.8–2.0 times longer than pronotum; width at apex 1.4–1.5 times width at base. Eyes 1.3–1.6 times as high as wide; 0.7–0.7 times more separated above than below. Pronotum 1.8–1.9 times as wide at base as long. Prosternum length 1.0–1.1 times the coxal width. Scutellum 0.6–0.8 times as long as wide. Elytra 1.6–1.9 times as wide as pronotum; 1.4–1.6 times as long as wide; 4.4–4.9 times as long as pronotum. Ventrites III and IV with posterior retraction not sinuate and reaching the middle of the segment.

Remarks. This is one of the smallest species of Anchylorhynchus (up to 4 mm pronotum + elytra), with the only other species of similar size being Anchylorhynchus bicarinatus ( Figure 10G ). Anchylorhynchus minimus can be distinguished from the latter by the seven carinae of the rostrum (as in Figures 2 A–B), while A. bicarinatus has 2–3 carinae (Figures I–J). It can additionally be diagnosed by the following characters: transverse pronotum (about 2 times as wide as long) with scales directed to the apex ( Figure 8O ); rostrum about 2 times longer than the pronotum; mandible with external tooth truncated ( Figure 4D ) and maxilla without apical setae in palpomere I ( Figure 5D ).

Most specimens of Anchylorhynchus minimus are uniformly yellow in color, but a recent series sampled in Espírito Santo, Brazil and deposited in MZSP includes one male with dark spots on the elytra similar to those of Anchylorhynchus burmeisteri , but without a band of dark scales throughout the epipleura and with yellow scales interspersed with the dark scales in the posterior part of the spots.

Geographical Distribution. This species is found from northeastern Argentina to Espírito Santo, Brazil ( Figure 24 ).

Host Plants. Euterpe edulis Mart. and likely another species.

Bondar (1950) states that the type series was collected by A. Maller from a “short grassland palm” (“palmito rasteiro do campo”). Viana (1975) says the specimens from Misiones, Argentina were collected in flowers of “palmito ( Euterpe edulis )”. The more recently collected specimens, from Espírito Santo, Brazil, were sampled from Euterpe edulis . This is a tall rainforest species, so it is likely that the type series was collected from a different host.

Examined Specimens. Type Material. BRAZIL. Santa Catarina: Corupá, A. Maller, no date (♀ lectotype Anchylorhynchus minimus AMNH) .

Other Material. ARGENTINA. Misiones: San Antonio, M. J. Viana, XI/1954 (30♀, 23♂, 70 sex undetermined MACN, 1♀, 4♂ MZSP); Santa Maria, M. J. Viana, X/1947 (2♀, 2♂ MACN) .

BRAZIL. Espírito Santo: Alegre, Liana H. G. Mengarda, 01/IX/2017 (5♀, 4♂ MZSP) . Rio de Janeiro: Rio de Janeiro , Corcovado, M. Alvarenga, XII/1967 (1♀, 1♂ MZSP) ; Rio de Janeiro, Floresta da Tijuca , M. Alvarenga, I/1958 (2♂ MZSP) . Santa Catarina: Corupá, A. Maller, I/1954 (1♂ MNRJ) ; XII/1953 (1♂ MNRJ) .

NO COUNTRY. No region: No locality, no collector, no date (1 sex undetermined MACN).

Figures

FIGURE 2. Heads of species of Anchylorhynchus. Scale: 500 µm. A A. centrosquamatus, male, showing five well-defined dorsal carinae in the rostrum and scales on the head directed to the interocular fovea. B A. centrosquamatus, male, showing the pairs of lateral carinae along the scrobe, totaling 7 carinae in the rostrum. C A. pinocchio, female, showing five dorsal carinae poorly defined towards the base. D A. pinocchio, female, showing the lateral carinae poorly defined towards the base. E A. aegrotus, showing scales in the head smaller and directed to the base of the head. F A. burmeisteri, showing scales in the head directed to the rostrum. G A. tricarinatus, male, showing three well-defined dorsal carinae. H A. tricarinatus, male, showing no lateral carinae. I A. bicarinatus, male, with three well-defined dorsal carinae. H A. bicarinatus, male, with only two dorsal carinae and no central carina.

FIGURE 3. Antennae of males of species of Anchylorhynchus. Scales: 500 µm. A A. bicolor. B A. chrysomeloides. C A. variabilis D A. minimus. E A. pinocchio. F A. trapezicollis. G A. latipes. H A. rectus. I A. albidus.

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 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 15. Prosterna of species of Anchylorhynchus, ventral view. Scales: 500 µm. A A. bicarinatus. B A. camposi. C A. chrysomeloides. D A. variabilis.

FIGURE 16. Meso- and metathorax of species of Anchylorhynchus, lateral view. Scales: 500 µm. A A. camposi. B A. burmeisteri. C A. multisquamis. D A. variabilis.

FIGURE 18. Prolegs of species of Anchylorhynchus. Scales: 500 µm. A A. burmeisteri, male. B A. camposi, male. C A. multisquamis, male. D A. minimus, male. E A. pinocchio, male. F A. tricarinatus, male. G A. variabilis, male. H A. trapezicollis, male. I A. trapezicollis, female. J A. latipes, male. K A. latipes, female.

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.