Piezonotus Schoenherr, 1834

Riedel, Alexander, 2024, Taxonomic review of weevils of the tribe Celeuthetini, mainly from Sundaland, Sulawesi and the Lesser Sunda Islands (Coleoptera, Curculionidae, Entiminae), Zootaxa 5464 (1), pp. 1-75 : 50-52

Piezonotus Schoenherr

Piezonotus Schoenherr, 1834: 477–478 .

Coptorhynchus Guérin-Méneville 1841: 191 ; syn. n.

Stereogastrus Marshall, 1956: 125 ; synonymy by Alonso-Zarazaga & Lyal, 1999: 148.

Picronotus Marshall, 1956: 106–108 ; syn. n.

Platyspartus Faust, 1897: 247–248 ; syn. n.

Type species: Piezonotus suturalis Gyllenhal, 1834 , by original designation.

Description. Integument usually with appressed green scales, evenly spread or arranged in patches (rarely scales indistinct, e.g. minute in P. latiscapus Heller, 1896 or transparent in P. niger ( Günther, 1938)) ; intervals with rows of more or less distinct granules bearing subrecumbent scales. Head with angulate transverse sulcus. Eyes convex; separated from apex of prothorax by ca. 0.5–0.7 X length of eye (except 1.2 X in P. latiscapus ). Rostrum 1.16–1.33 X as long as wide, sides subparallel; apical declivity distinct, usually with sunk-in scales (subglabrous in P. asper ( Pascoe, 1881)) ; dorsal profile subangulate. Antenna. Scape slender; in cross-section subrotund; subapically clavate (except in P. latiscapus flattened; from base markedly widening, anteriorly laminate). Funicle with article 2 slightly shorter (0.80–0.96 X) than article 1. Metanepisternum narrow. Elytra usually subovate (elongate in P. latiscapus Heller ), with 10 striae, stria 10 abbreviated. Legs. Protibia ventrally simple or in apical half weakly granulate or denticulate. Mesoventral process trapezoid to subtriangular, 1.28–3.00 X as long as posterior width. Abdomen. Male ventrites 1–2 and females of some species (e.g. P. latiscapus , and P. narinosus ( Heller, 1900)) ca. 1.2–2.6 X longer than ventrites 3–5. Female abdominal ventrites 1–2 of many species ca. 4 X longer than ventrites 3–5; ventrite 3 apically densely setose; ventrites 4–5 internalized, fully concealed by elytra, as in figs 41a–c. Genitalia. Penis ( Figs. 29b , 30b , 31b , 32b ) with apex usually asymmetrical, right half forming process, ostium shifted to the left; species related to P. ternatensis ( Guérin-Méneville, 1841) with more or less symmetrical apex. Apodeme firmly attached to body. Endophallus long, in repose folded several times. Transfer apparatus spiniform, curved, ca. 0.3–0.6 X as long as body of penis.

Notes. The genus Piezonotus Schoenherr is here used in a wider sense, comprising the numerous species previously contained in Coptorhynchus Guérin-Méneville. As demonstrated by molecular phylogenies ( Toussaint et al. 2015 and other unpublished reconstructions) the species traditionally placed in Piezonotus Schoenherr are deeply nested within this group. The same is true of Picronotus Marshall and Platyspartus Faust. In this extended sense, Piezonotus Schoenherr is sister to Mesocoptus Marshall. Both genera form a more comprehensive clade together with Temnogastrus Marshall and Tarunus Marshall. It is remarkable that most of these genera share the character of a modified female venter described by Voss (1940: 279) and Marshall (1956: 126) with ventrites 4–5 more or less dorsally retracted. However, there are exceptions, i.e., the species originally included by Marshall in Mesocoptus Marshall , P. latiscapus Heller , and P. narinosus ( Heller, 1900) all have the plesiomorphic morphology of the venter with ventrites 3–5 fully exposed and on the same level ( Fig. 41d ). The majority of species formerly included in Coptorhynchus have a female venter with relatively thin and soft ventrites 4–5 deeply retracted into the elytral cavity ( Figs. 41a–c, 41e ). In the type species, Piezonotus suturalis Gyllenhal ventrite 4 forms a thin, dentate blade, overlapping ventrite 5 ( Fig. 41e ). The same applies to the species of Temnogastrus Marshall , Piezonotus asper (Pascoe) and at least one species formerly included in Coptorhynchus , P. sternalis ( Heller, 1900) ( Fig. 41f ). Tarunus Marshall shows a slight modification with ventrite 4 forming a narrow median process overlapping ventrite 5. To complicate matters, similar modifications of female ventrites 3–5 were gained in at least two to three other groups independently: within Celeuthetini , some species of Platyacus Faust, 1897 from the Solomon Islands ( Marshall, 1956: 70), as well as Machaerostylus Heller, 1934 ( Fig. 41h ) from New Britain. Furthermore, among the Pachyrrhynchini some Moluccan species of the genus Sphenomorpha Behrens, 1887 ( Fig. 41g ). Obviously, this remarkable character has to be treated with great caution when putting it to use in phylogenetic reconstruction.

Piezonotus Schoenherr is highly diverse in Sulawesi and the Moluccas. It needs to be revised in a separate, detailed study. The formal transfer of all species currently placed in Coptorhynchus Guérin-Méneville should be done in that context.

Figures

FIGURE 29. Piezonotus asper (Pascoe). Isomerinthus asper Pascoe, lectotype: (a) Habitus (b) Penis (c) Labels.

FIGURE 30. Piezonotus suturalis Gyllenhal. (a) Habitus (b) Penis; c–e, lectotype: (c) Habitus (d) Profile (e) Labels.

FIGURE 31. Piezonotus ternatensis (Guérin-Méneville). (a) Habitus (b) Penis; c-e, holotype: (c) Habitus (d) Profile (e) Labels; images by courtesy of MNHN / Christophe Rivier.

FIGURE 32. Piezonotus latiscapus Heller. (a) Habitus (b) Penis.

FIGURE 41. Celeuthetini, female abdominal venter; numbers refer to the respective ventrites: (a) Piezonotus laccophilus (Heller), ventral aspect (b) Piezonotus laccophilus (Heller), oblique latero-ventral aspect of apex (c) Piezonotus laccophilus (Heller), lateral aspect, elytra removed (d) Piezonotus sp. labelled “aeruginosus (Faust)”, ventral aspect (e) Piezonotus suturalis Gyllenhal, ventral aspect (f) Piezonotus sternalis (Heller), oblique latero-ventral aspect of apex (g) Sphenomorpha wallacei Behrens, oblique latero-apical aspect (h) Machaerostylus sp., oblique latero-ventral aspect.