Piazurini Lacordaire, 1865: 144

Anzaldo, Salvatore S., 2017, Review of the genera of Conoderinae (Coleoptera, Curculionidae) from North America, Central America, and the Caribbean, ZooKeys 683, pp. 51-138 : 64-65

Piazurini Lacordaire, 1865: 144

Classificatory history and current circumscription.

This tribe was originally characterized by Lacordaire (1865: 144) for the genera Cratosomus , Pinarus , and Piazurus in recognition of the strongly canaliculate prosternum, the “gutter-like” modification to the mesoventrite and the clavate, non-carinate hind femora that do not or only slightly exceed the abdominal apex. Heller (1906: 31) produced a key to Piazurini that includes 8 of the 12 currently recognized genera - not included are Lobops , Latychellus Hustache, 1938, Hedycera , and the Old World Guiomatus - based largely on the relative size of abdominal ventrites and the amount that they ascend, relative lengths of funicular articles, and the construction of the mesoventrite.

The monotypic South American genus Hedycera is moved to the Piazurini despite the occurrence of the genus outside the geographic focus of this paper. The exposed pygidium that is not completely visible in dorsal view, the large triangular tooth on the hind femur, the transverse posteromedial depression on the metaventrite (discussed further below), and the unarmed femoral apices place the genus not only in the Piazurini but in a hypothesized clade containing Piazurus , Pseudopiazurus Heller, 1906, Pseudopinarus Heller, 1906 and the South American Piazolechriops Heller, 1906. Hedycera megamera Pascoe, 1870 would key out to couplet 7 of Heller’s 1906 key (containing Pseudopinarus and Piazolechriops ), for having abdominal segments only slightly ascending, abdominal segment 2 not being longer than 3 and 4 combined, and the presence of " superciliarleisten ", referring to the arcuate carina at the vertex of the head found in most members of these genera (though not in a few species of Pseudopinarus ), a greatly elongate antennal funicular article 2, and a slender rostrum. Hedycera can be differentiated from these by the shape of the pronotum in dorsal view, which is widest in the anterior half just before the subapical constriction, and in having elongate setae on the antennal funicular articles. When originally describing the monotypic genus, Pascoe (1870) stated that it was most closely related to Piazurus , which was later agreed with by Champion (1906: 713). Hedycera is the first genus separated in Heller’s key (1895) for having similar-sized abdominal ventrites 2, 3, and 4, but is not treated further in that publication. In the catalogs of Hustache (1934: 45) and Blackwelder (1947: 884) Hedycera is listed under the otherwise entirely Old World-distributed conoderine tribe Mecopini Lacordaire, 1865 and was moved to Lechriopini in Wibmer and O’Brien (1986: 19), without a justification provided in either placement.

Variation in key character systems.

The modification to the mesoventrite in the genera treated here in the Piazurini varies from being a cup-shaped receptacle (as in Lobops ; Fig. 2 ) to structured similarly to a cup-shaped receptacle but with the posterior margin flattened and depressed at least slightly below the level of the lateral margins of the channel (Figs 3 , 4 ) allowing the rostrum to pass through to the metaventrite if long enough. The eyes are often smaller and more separated and are not or not as sharply acuminate ventrally or laterally inflexed (Figs 38 , 39 ) as in many Lechriopini and Zygopini , but can be quite large and contiguous or subcontiguous (Figs 40-41 ), taking up most of the surface of the head as well as be slightly ventrally acuminate to slightly laterally inflexed. The pygidium is exposed but not entirely visible in dorsal view (somewhat concealed from above by the elytral apex; e.g. Fig. 68 ), usually only visible completely in posterior or ventral view. Abdominal ventrites are flat to slightly, evenly ascending. The vestiture consists of thick setae to small scales, usually not covering most of the body surface except in Lobops , which has large, flat and round scales. The femora are at least slightly clavate, the hind femur is without a lateral carina and lacks teeth at the mesal and lateral apical faces (Fig. 60 ; in most lechriopines and zygopines, a tooth is usually present at the mesal and/or lateral face of the femoral apex on the middle and/or hind legs as in Figs 61-63 ), and several genera have a large, laterally compressed, triangular ventral tooth. This large triangular tooth is also found in other conoderine tribes (e.g. Menemachini Lacordaire, 1865; Campyloscelini Schoenherr, 1845) as well as other groups of weevils (e.g. Hylobiini Kirby, 1837). Despite this homoplasious distribution in Curculionidae it likely represents a single origin within the Piazurini , with the genera having it also sharing additional characters; it is also not found in other New World Conoderinae , making it useful for diagnosing the group of Piazurines that bear it.

Additional characters of potential phylogenetic significance.

The metaventrite posteromedially has a transverse depression, not with a narrow longitudinal sulcus extending variably anteriorly as in most Lechriopini and Zygopini (but many species of Cratosomus have a broad longitudinal depression). The antennal club is typically more spherical to ovoid, with the suture between at least articles 2 and 3 sinuate (but also found in a few lechriopines and zygopines). A mesal process of the procoxae is absent in most piazurines and found in many lechriopines and zygopines (though present, among the Central American species observed, in Pseudopinarus , Lobops bonvouloiri (Hustache, 1932), and in the species Piazurus alternans Kirsch, 1875). Sclerolepidia are absent in Piazurini ( Lyal et al. 2006: 237). Additionally, piazurines are quite different behaviorally from the remainder of the New World Conoderinae , typically being less active in the daytime and no species are known to be part of the several widespread mimicry complexes found in the tribes Lechriopini and Zygopini ( Hespenheide 1995).

Diversity and distribution.

Fifty-two species are currently known from north of South America in five genera. Six additional genera are known only from South America, and one genus, Guiomatus , occurs in Papua New Guinea.

Figures

Figures 1 - 9. Variation in the mesoventrite. 1 Trichodocerus brevilineatus [ARTSYS 0000616] showing a prosternal rostral " sheath " with the sides converging below the procoxae, the transverse ridge anterior to the mesocoxae and the region of the mesoventrite posterior to the ridge with dense yellow scales 2 Lobops bonvouloiri [ARTSYS 0000527] showing a cup-shaped receptacle for receiving the rostrum 3 Piazurus trifoveatus [SSAC 0001118] with an " open " channel on the mesoventrite 4 Pseudopinarus condyliatus [SSAC 0001116] with an " open " channel on the mesoventrite 5 Acoptus suturalis [ASUHIC 0016914] showing a flat, unmodified mesoventrite 6 Copturus sanguinicollis [ASUHIC 0086638] showing a closed receptacle on the mesoventrite with lateral flanges 7 Cylindrocopturinus pictus [SSAC 0001288] showing a rostral channel of the mesoventrite formed by relatively parallel carinae and no posterior termination 8 Euzurus ornativentris [ARTSYS 0000796] 9 Hoplocopturus javeti [SSAC 0001289] with an inverted U-shaped carina and the region posterior to the carina invaginated.

Figures 37 - 45. Variation in eye shape. 37 Trichodocerus brevilineatus [ARTSYS 0000609] with large, subcontiguous eyes that continue below rostral insertion 38 Cratosomus punctulatus mexicanus [ASUHIC 0031510] with relatively small, widely separated eyes 39 Lobops bonvouloiri [ARTSYS 0000658] with widely separated eyes and the frons concave between the upper half of the eye 40 Pseudopiazurus centraliamericanus [ASUHIC 0086627] with very large eyes that are contiguous in upper half 41 Pseudopinarus guyanensis [ASUHIC 0086636] with large, subcontiguous eyes and an arcuate carina on the vertex of the head 42 Acoptus suturalis [ASUHIC 0016914] with subcontiguous eyes separated at the top by a lanceolate space 43 Cylindrocopturinus pictus [SSAC 0001288] 44 Macrocopturus lynceus [SSAC 0001085] with very large, partially contiguous eyes 45 Microzygops nigrofasciatus [ARTSYS 0000802] with large eyes contiguous in the bottom 2 / 3 and widely separated at the top.

Figures 67 - 70. Lateral and dorsal habitus images of Trichodocerini and Piazurini. Scale bars = 2 mm unless otherwise specified. 67 a-b Trichodocerus spinolae [ARTSYS 0000534] 68 a-b Cratosomus lafontii [SSAC 0001133]; scale bars = 10 mm 69 a-b Lobops bonvouloiri [ARTSYS 0000527] 70 a-b Piazurus caprimulgus [SSAC 0001113].

Figures 55 - 66. Miscellaneous morphological structures. 55 Hoplocopturus sulphureus [ARTSYS 0000801] with an overlay showing an elongate second funicular article that is more than twice the length of the first 56 Lissoderes subnudus [SSAC 0001064] with an overlay showing a second funicular article that is subequal to the first, and seven distinct funicular articles 57 Philinna bicristata [ARTSYS 0000799] showing a funiculus composed of six articles 58 Microzurus sp. [SSAC 0001290] showing a short, slender fifth tarsal article and minute claws 59 Philides comans [ARTSYS 0000804] with a broad tooth at the base of the tarsal claw 60 Left metafemoral apex of Piazurus trifoveatus [SSAC 0001118] that is unarmed at the mesal and lateral faces 61 Left metafemoral apex of Cylindrocopturinus pictus [SSAC 0001288] with a tooth only at the mesal face 62 Left metafemoral apex of Peltophorus polymitus seminiveus [SSAC 0001117] showing a small tooth at both mesal and lateral faces 63 Left metafemoral apex of Hoplocopturus sulphureus [ARTSYS 0000801] showing a small tooth at the lateral face and an acuminate process at the mesal face 64 Metaventrite of Pseudopiazurus centraliamericanus [SSAC 0001291] showing deep, arcuate sulc 65 Lateral view of the metathorax of Euzurus ornativentris [ARTSYS 0000796] showing a large tubercle in anterior to the metacoxa 66 Dorsal view of the profemora of Copturomimus caeruleotinctus [SSAC 0001059] showing denuded, striolate regions.