Neomecopus Hustache, 1921

Fujisawa, Yusuke, Yoshitake, Hiraku & Kojima, Hiroaki, 2025, Weevils of the genus Neomecopus Hustache, 1921 (Curculionidae: Conoderinae: Mecopini), with description of a new species from the Ryukyus, Japan, Zootaxa 5631 (3), pp. 574-584 : 575-577

Neomecopus Hustache, 1921

[Japanese name: Shirafu-kumo-zômushi-zoku]

( Figs 1–4 , 13, 16 )

Neomecopus Hustache, 1921: 91 (type species: Neomecopus subarmatus Hustache, 1921 ; Zygopini); Hustache, 1934: 42 (cataloged; Mecopini ); Morimoto, 1962a: 199 (cataloged); Morimoto, 1962b: 47 (in key); Morimoto, 1989: 515 (in checklist); Alonso-Zarazaga & Lyal, 1999: 112 (cataloged); Kojima & Morimoto, 2004: 107 (cataloged); Lyal, 2013: 216 (cataloged); Alonso-Zarazaga et al., 2017: 167 (cataloged); Alonso-Zarazaga et al., 2023: 165 (cataloged); Fujisawa, 2023: 11 (biological note & distribution range); Tseng et al., 2024: 11 (similarity with Pempheres ).

Diagnosis. This genus is distinguishable from its related genera by a combination of the following features: antennae with very long club, longer than all funicular segments combined ( Fig 1 ); procoxae distant ( Fig 2 ); prosternum with pair of minute spines ( Fig 2 ); mesosternal process prominent ventrally, with pair of tubercles basi-laterally ( Fig 3 ); metafemora exceeding elytral apices ( Fig 4 ); protibiae slightly sinuate ( Figs 13, 16 ).

Redescription. Length: 4.6–6.6 mm; width: 1.9–2.8 mm. Body oblong-ovate. Eyes subcontiguous at basal and subapical parts, carinate along inner margin of each eye. Rostrum longer than pronotum, gently curved throughout, cylindrical, squamate near base; antennal scrobes placed on latero-ventral surface of rostrum, with definitely ridged margins. Antennae with scape reaching base of rostrum; funicle with segment I longest, II longitudinal, III to VI transverse; club very long, slightly thickened toward tip, covered with fine recumbent pubescence, four-segmented, with segment I longer than length of all funicular segments combined, suture between segments I and II oblique.

Prothorax transverse, rounded on sides, with weak subapical constriction; basal margin bisinuate; apical margin broadly emarginate. Scutellum large, subtrapezoidal. Elytra about twice as long as pronotum, dorsally convex medially, subparallel-sided in basal half, separately rounded at apices; intervals III to V each with row of small pointed tubercles; all striae originated from base, deeply punctate. Pygidium almost concealed. Femora toothed; profemora slightly thicker than middle pair; metafemora longest, exceeding elytral apices, with triangular tooth larger than those of front pair. Tibiae with inner margins slightly sinuate, acutely uncinate at apex.

Prosternum with pair of minute spines before procoxae, space between spines neither depressed nor foveate. Procoxae separated from each other. Mesosternal process reaching middle of mesocoxae, prominent ventrally, with pair of tubercles apico-laterally. Venter with large ventrite I, which is about 1.6 times as long as ventrites II to V combined.

Distribution. Japan (Hokkaido, Honshu, Shikoku, Kyushu; and the Ryukyus––new record).

Comments. The distribution range of this genus was limited to Hokkaido, Honshu, Shikoku, and Kyushu, but the new species described herein extends the southern limit to the Ryukyus.

Key to Neomecopus and its related genera

Neomecopus shares the large, subtrapezoidal scutellum nearly as wide as the first elytral intervals with mecopine genera Chirozetes , Daedania , and Pempheres from the Palaearctic and Oriental regions ( Marshall 1941). We also confirmed that the same characteristics are present in Mecopus Schoenherr, 1825 and Mecopomorphus Hustache, 1920 and included these in the key as well Neomecopus can be distinguished from these five genera by the following key.

1 Prosternum simple, with no spines in either sex............................................................. 2

1’ Prosternum armed with pair of large or small spines at least in male............................................. 3

2 Metafemora each with triangular tooth which is pectinate on outer margin and larger than front and middle pairs................................................................................................. Mecopomorphus

2’ Metafemora each with small tooth as large as front and middle pairs..................................... Pempheres

3 Prosternum with minute spines in both sexes. Antennal club with segment I remarkably elongate, longer than funicle................................................................................................. Neomecopus

3’ Prosternum with spines well-developed in male or vestigial to minute in female. Antennal club with segment I shorter than funicle.............................................................................................. 4

4 Internal margins of protibiae each with small lamellate projection before middle. Profemora each with triangular tooth almost as large as those on middle and hind pairs........................................................... Daedania

4’ Internal margins of protibiae more or less straight or faintly sinuate. Profemora each with triangular tooth smaller than those on middle and hind pairs.................................................................................. 5

5 Antennae with funicular segment II as long as or at most slightly longer than I. Procoxae separated in both sexes... Chirozetes

5’ Antennae with funicular segment II much longer than I. Procoxae contiguous to subcontiguous (male) or separated (female)............................................................................................. Mecopus

Figures

FIGURE 4. Elytra and metafemora of Neomecopus subarmatus, in dorsal view.

FIGURES 1–3. Neomecopus subarmatus. 1, Antenna (a: club; b: funicle); 2, a pair of minute spines of prosternum (triangular marks); 3, a pair of basi-lateral tubercles of mesosternal process (triangular marks).

FIGURES 13–18. Femora and tibiae of Neomecopus spp., in ventral view. 13–15, N. subarmatus; 16–18, N. tamaderai. 13 & 16, front legs; 14 & 17, middle legs; 15 & 18, hind legs.