Principio del formulario Final del formulario



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The number of funicular articles can be reduced to six, five or even four, in some weevil taxa. For example in Dryopthorinae the funicle has six or less articles, because the last funicular article is added to the club, forming a basal shiny portion of it (Fig. 2E). The club may be compact, as in Curculionidae (Fig. 2D), or loosely articulated as in most basal families (Fig. 2A and 2B). In the latter case the club may be indistinct when its articles are similar to those of the funicle, e.g., in some Belidae (Fig. 2A), but the club articles are usually recognised for being wider and more pilose (Fig. 2B and 2H). The males of Cylas formicarius (Fabricius) (Brentidae, Cyladinae) have a particular antenna with nine articles followed by a very elongate club formed by articles 10-11 (Fig. 2C).

Antennae are usually inserted between midlength and apex of the rostrum (Fig. 2F), and in some cases near rostral base (Fig. 2G). The insertion is mostly lateral, but some weevils have dorsal or ventral (Fig. 2H) antennal insertions.

Rostrum (Fig. 3). The presence of a rostrum extended beyond the eyes, with mouth-parts situated at its apex, is one of the most typical features of Curculionoidea (Fig. 1C). The shape, length and width of the rostrum show great variation among weevil taxa, from long and slender (e.g., "long-nosed weevils", as Curculioninae) (Fig. 3C) to short and broad (e.g., "broad-nosed weevils, as Entiminae) (Fig. 3B), and it can be reduced or even absent (Fig. 3A) in some specialised groups (e.g., Scolytinae, Platypodinae). The rostrum is frequently sexually dimorphic, particularly in those weevils that use it for oviposition site preparation (e.g., in females the rostrum is usually longer and with antennal insertion more basal than in males).

The lateral rostral grooves for the reception of the scape in repose are called "scrobes" (Fig. 1C), which may have different extension and curvature (Fig. 3B to 3E).







Fig. 3: Characters of rostrum: (A) vestigial, Megaplatypus mutatus (Chapuis) (Curculionidae, Platypodinae); (B) short and broad, "broad-nosed weevils", Naupactus xanthographus (Germar) (Curculionidae, Entiminae); (C) long and slender, "long-nosed weevils", Celetes trithrinacis Bondar (Curculionidae, Curculioninae, Derelomini); (D) scrobe extended towards venter of rostrum, lateral view, Omoides flavipes (Blanchard) (Curculionidae, Eugnominae); (E) scrobe not extended towards venter of rostrum, lateral view, Listronotus argentinensis (Hustache) (Curculionidae, Rhythirrininae); (F) prosternal channel for the reception of rostrum in repose, antero-lateral view, Cratosomus fasciatus Perty (Curculionidae, Conoderinae); (G) prosternal channel with cup-like receptacle, antero-lateral view, Faustinus cubae (Boheman) (Curculionidae, Cryptorhynchinae). Scale = 1 mm, except F = 5 mm.

Caracteres del rostro: (A) vestigial, Megaplatypus mutatus (Chapuis) (Curculionidae, Platypodinae); (B) corto y ancho, "gorgojos de rostro ancho", Naupactus xanthographus (Germar) (Curculionidae, Entiminae); (C) largo y delgado, "gorgojos de rostro largo", Celetes trithrinacis Bondar (Curculionidae, Curculioninae, Derelomini); (D) escroba extendida hacia la superficie ventral del rostro, vista lateral, Omoides flavipes (Blanchard) (Curculionidae, Eugnominae); (E) escroba no extendida hacia la superficie ventral del rostro, vista lateral, Listronotus argentinensis (Hustache) (Curculionidae, Rhythirrininae); (F) canal prosternal para la recepción del rostro en reposo, vista antero-lateral, Cratosomus fasciatus Perty (Curculionidae, Conoderinae); (G) canal prosternalcon receptáculo en forma de copa, vista antero-lateral, Faustinus cubae (Boheman) (Curculionidae, Cryptorhynchinae). Escalas = 1 mm, excepto F = 5 mm.



Some weevils have a ventral cavity or sternal channel for the reception of the rostrum in repose (Fig. 3F and 3G). The channel may be only prosternal, it can also comprise the mesosternum, and in some few cases it extends to the metasternum, or even further, towards ventrites. In Cryptorhynchinae, the channel ends in a cup-like receptacle (Fig. 3G).

Ventral surface of head and mouth-parts (Fig. 4). In most weevils, the ventral surface of the head has a single median gular suture (Fig. 4E), anteriad to postoccipital suture, and thus the gula is indistinct (see Lyal 1995). Only in some basal weevils (e.g., Nemonychidae, Belidae) the gular sutures are separate (Fig. 4G) and delimite a gular sclerite or gula, located between the submentum and the neck membrane.



Mouth-parts are located at the apex of the rostrum (Fig. 1B). The labrum and the clypeolabral suture (dorsal view) are indistinct in most Curculionoidea (Fig. 4B), except in Nemonychidae and Anthribidae (Fig. 4A). The labium (ventral view) has a prementum, which can be pedunculate, and a posterior sclerite called submentum, also regarded as "pregula" (Fig. 4E). The extent to which the labial prementum covers the maxillae determines two types of mouth-parts: in the Adelognathous type the maxillae are hidden by a enlarged prementum (Fig. 4D), and in the Phanerognathous type the maxillae are visible continuously at sides of the prementum (Fig. 4E). When the prementum is relatively small, it is usually pedunculate (Fig. 4E). Characters of the labial and maxillary palpi, such as insertion, direction and number of articles are useful as taxonomic characters at family and subfamily levels. The maxillary palpi are elongate and projecting in those basal weevils with a distinct labrum (Fig. 4C), and compact in the remaining curculionoids (Fig. 4D, 4E and 4F).





Fig. 4: Characters of mouth-parts: (A) Labrum distinct, mandibles lacking teeth on outer edge, dorsal, Anthribidae, Anthribinae; (B) Labrum indistinct, mandibles exodontous, Attelabidae, Rhynchitinae; (C) maxillary palpi elongate and projecting, ventral, Anthribidae, Anthribinae; (D) mouth-parts of Adelognathous type (maxillae hidden by enlarged prementum), ventral, Naupactus xanthographus (Germar) (Curculionidae, Entiminae); (E) mouth-parts of Phanerognathous type (maxillae visible on each side of prementum), ventral, Heilipodus argentinicus (Heller) (Curculionidae, Molytinae, Hylobiini); (F) labial palpi seemingly one-segmented, ventral, Lixus sp. (Curculionidae, Lixinae); (G) gular sutures separate, ventral, Belidae, Oxycoryninae; (H) pregular sclerite distinct, ventral, Megaplatypus mutatus (Chapuis) (Curculionidae, Platypodinae). Scales = 1 mm.

Caracteres de la piezas bucales: (A) Labro conspicuo, mandíbulas sin dientes en la superficie externa, vista dorsal, Anthribidae, Anthribinae; (B) Labro inconspicuo, mandíbulas exodontas, Attelabidae, Rhynchitinae; (C) palpos maxilares elongados y proyectados, vista ventral, Anthribidae, Anthribinae; (D) piezas bucales de tipo Adelognato (maxilas cubiertas por un prementón amplio), vista ventral, Naupactus xanthographus (Germar) (Curculionidae, Entiminae); (E) piezas bucales de tipo Fanerognato (maxilaa visibles a cada lado del prementón), vista ventral, Heilipodus argentinicus (Heller) (Curculionidae, Molytinae, Hylobiini); (F) palpos labiales aparentemente con un solo segmento, vista ventral, Lixus sp. (Curculionidae, Lixinae); (G) suturas gulares separadas, vista ventral, Belidae, Oxycoryninae; (H) esclerito pregular conspicuo, vista ventral, Megaplatypus mutatus (Chapuis) (Curculionidae, Platypodinae). Escalas = 1 mm.



The mandibles are relatively large, robust, and setose and/or squamose in "broad-nosed weevils", and usually smaller, glabrous or with few setae in "long-nosed weevils". Moreover, the mandibles of broad-nosed weevils usually bear a scar, left by a deciduous process (Fig. 4D). These processes or cusps have different sizes and shapes (see Thompson 1992), being presumably used by the adult to emerge from the pupal cell and to dig its way out of the soil. They are subsequently lost by active dehiscence when feeding takes place.

The inner margin of the mandibles is usually dentate, but the outer edge is not (Fig. 4A and 4E), except in some groups such as Rhynchitinae, with exodontous mandibles (with teeth on outer edge) (Fig. 4B). In most weevils the mandibles are attached laterally, having a quite horizontal movement, but in Curculionini the attachment point is located dorsally and the mandibles move vertically.



Eyes, frons and head (Fig. 5). Eyes are usually faceted, except in some Brentinae which have smooth eyes (with indistinct ommatidia). The shape, convexity, relative size and position of the eyes provide valuable characters. They can be round (Fig. 5A), longitudinally oval (Fig. 5B and 5C) or transversely oval (Fig. 5E); flat to strongly convex (Fig. 5G and 5H), reduced to absent (e.g., some Cossoninae that inhabit caves), or very large and dorsally contiguous (e.g., several Conoderinae) (Fig. 5F).





Fig. 5: Characters of eyes, frons and head: (A) eyes round, lateral view, Apion lativentre Béguin-Billecocq (Brentidae, Apioninae); (B) longitudinally oval, lateral view, Lixus sp., (Curculionidae, Lixinae); (C) longitudinally oval and ventrally aproximate, lateral view, Baris vianai Hustache (Curculionidae, Baridinae); (D) partially covered by postocular lobes, lateral view, Ceutorhynchus argentinensis (Hustache) (Curculionidae, Curculioninae Ceutorhynchini); (E) transversely oval, antero-lateral view, Phelypera schuppeli (Boheman) (Curculionidae, Hyperinae); (F) dorsally contiguous, antero-lateral view, Eulechriops manihoti Monte (Curculionidae, Conoderinae); (G) head of a "broad-nosed weevil", dorsal view, Naupactus xanthographus (Germar) (Curculionidae, Entiminae); (H) head of a long-nosed weevil", dorsal view, Anthonomus sisymbrii Hustache (Curculionidae, Curculioninae, Anthonominae); (I) head as wide as prC onotum and exposed in dorsal view, Megaplatypus mutatus (Chapuis) (Urculionidae, Platypodinae); (J) head narrower than pronotum and concealed by it in dorsal view, Pityophthorus sp. (Curculionidae, Scolytinae). Scale = 1 mm.

Caracteres de los ojos, frente y cabeza: (A) ojos redondos, vista lateral, Apion lativentre Béguin-Billecocq (Brentidae, Apioninae); (B) longitudinalmente ovales, vista lateral, Lixus sp. (Curculionidae, Lixinae); (C) longitudinalmente ovales y ventralmente aproximados, vista lateral, Baris vianai Hustache (Curculionidae, Baridinae); (D) parcialmente cubiertos por lóbulos oculares, vista lateral, Ceutorhynchus argentinensis (Hustache) (Curculionidae, Curculioninae Ceutorhynchini); (E) transversalmente ovales, vista antero-lateral, Phelypera schuppeli (Boheman) (Curculionidae, Hyperinae); (F) dorsalmente contiguos, vista antero-lateral, Eulechriops manihoti Monte (Curculionidae, Conoderinae); (G) cabeza de un "gorgojo de rostro ancho", vista dorsal, Naupactus xanthographus (Germar) (Curculionidae, Entiminae); (H) cabeza de un "gorgojo de rostro largo", vista dorsal, Anthonomus sisymbrii Hustache (Curculionidae, Curculioninae, Anthonominae); (I) cabeza tan ancha como el pronoto y visible dorsalmente, Megaplatypus mutatus (Chapuis) (Curculionidae, Platypodinae); (J) cabeza más angosta que el pronoto y oculta por este último en vista dorsal, Pityophthorus sp., (Curculionidae, Scolytinae). Escala = 1 mm.



The frons may be broad (Fig. 5G) or narrow (Fig. 5F) depending on the relative size and proximity of the eyes. In some taxa there are superciliar arcs (e.g., some Aterpinae), preocular or postocular constrictions or impressions, or postocular lobes (e.g., Rhythirrininae) (Fig. 3E). The postocular lobes are projections of the antero-lateral margins of the pronotum, that could partially conceal the eyes (Fig. 5D).

The head usually extends a short distance from posterior margin of the eyes to the anterior margin of the pronotum, but sometimes (e.g., in most Eugnominae, some Brentinae) it is markedly prolonged behind the eyes (Fig. 6A). It could be as wide as the pronotum or narrower than the pronotum, visible from dorsal view (Fig. 5I) or concealed by the pronotum (Fig. 5J).







Fig. 6: Body shape (prothorax plus elytra): (A) elongate body form, with stepped ventrites, lateral view, Brentus anchorago (L) (Brentidae, Brentinae); (B) pyriform body form, with stepped ventrites, lateral view, Apion lativentre Béguin-Billecocq (Brentidae, Apioninae); (C) cylindrical body form, lateral view, Pityophthorus sp. (Curculionidae, Scolytinae); (D) rhomboidal body shape, not tuberculate, dorsal view, Gonipterus gibberus Boisduval (Curculionidae, Gonipterinae); (E) elongate and subparallel-sided, tuberculate, dorsal view, Aegorhinus superciliosus (Guérin) (Curculionidae, Aterpinae); (F) subrhomboidal body shape, dorsal view, Ameris ynca (Sahlberg) (Curculionidae, Molytinae, Cholini); (G) broadly oval body shape, dorsal view, Spermologus rufus Boheman (Curculionidae, Molytinae, Petalochiliini). Scales = 1 cm, except B and C = 1mm.

Forma del cuerpo (protórax más élitros): (A) cuerpo elongado, ventritos escalonados en vista lateral, Brentus anchorago (L) (Brentidae, Brentinae); (B) cuerpo piriforme, ventritos escalonados en vista lateral, Apion lativentre Béguin- Billecocq (Brentidae, Apioninae); (C) cuerpo subcilíndrico, vista lateral, Pityophthorus sp. (Curculionidae, Scolytinae); (D) cuerpo romboidal, élitros no tuberculados, vista dorsal, Gonipterus gibberus Boisduval (Curculionidae, Gonipterinae); (E) cuerpo elongado y de lados subparalelos, con élitros tuberculados, vista dorsal, Aegorhinus superciliosus (Guérin) (Curculionidae, Aterpinae); (F) cuerpo subromboidal, vista dorsal, Ameris ynca (Sahlberg) (Curculionidae, Molytinae, Cholini); (G) cuerpo anchamente oval, vista dorsal, Spermologus rufus Boheman (Curculionidae, Molytinae, Petalochiliini). Escala = 1 cm, excepto B y C = 1 mm.


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