Nephius Pascoe, 1885

Grebennikov, Vasily V., 2018, Dryophthorinae weevils (Coleoptera: Curculionidae) of the forest floor in Southeast Asia: DNA analysis of two new Nephius from Vietnam and Taiwan suggests non-monophyly of Stromboscerini, Zootaxa 4500 (3), pp. 381-387 : 382-383

publication ID

https://doi.org/ 10.11646/zootaxa.4500.3.5

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lsid:zoobank.org:pub:A0081D71-D208-40E7-88FA-86CA929E4E80

persistent identifier

https://treatment.plazi.org/id/03D42902-EE42-3843-FF47-F8B3FCA65918

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scientific name

Nephius Pascoe, 1885
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Nephius Pascoe, 1885 View in CoL

Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3

Type species: Nephius gestroi Pascoe, 1885 , by monotypy.

Diagnosis. Adults of the genus Nephius can be easily distinguished from those of other nominal (and likely not

most closely related) Stromboscerini ( Grebennikov 2018a, b) by the unique combination of two characters: (a) transversely truncated antennal club terminated with the conically protruding velvety apex (also found in Tasactes Faust ) and (b) presence of postocular lobes latero-ventrally on the prothorax ( Fig. 2C View FIGURE 2 , also found in Stromboscerus ). Diagnostics of the genus Nephius within the rest of Dryophthorinae is less straightforward due to the large size of the subfamily (some 160 genera, Alonso-Zarazaga & Lyal 1999) and to the lack of a phylogenetic framework. In situations when DNA data are not available, Nephius adults might be best recognized among other Dryophthorinae by a combination of the following morphological characters: (1) medium- or small bodied weevils with body length measured between anterior edge of pronotum and elytral apex not exceeding 8 mm; (2) relatively elongate body with long legs; (3) relatively long and evenly curved rostrum ( Figs 1C View FIGURE 1 , 2C View FIGURE 2 ); (4) ventrally contiguous ( Fig. 1E View FIGURE 1 ) or nearly continuous ( Fig. 2E View FIGURE 2 ) eyes; (5) 6-segmented antennal funicle ( Figs 1F View FIGURE 1 , 2F View FIGURE 2 ); (6) contiguous procoxae ( Figs 1B View FIGURE 1 , 2B View FIGURE 2 ); (7) minuscule tarsomere 4 almost fully hidden inside tarsomere 3 ( Figs 1G View FIGURE 1 , 2G View FIGURE 2 ); (8) elytral shoulders partly ( Fig. 1A View FIGURE 1 ) or markedly ( Fig. 2A View FIGURE 2 ) effaced (suggesting flightlessness and/or aptery); (9) odd elytral interstriae with short longitudinally oriented and pilose ridges ( Figs 1A, C–D View FIGURE 1 , 2A, C View FIGURE 2 –DG).

Diversity, distribution and biology. Including the two newly described species, the genus is formed by 11 nominal species and two subspecies listed in Grebennikov (2018a) and found in China, Indonesia, Malaysia, Myanmar, Taiwan and Vietnam. Biological information is restricted to the known collecting circumstances suggesting that adult Nephius inhabit the floor of deciduous forests.

Monophyly and phylogenetic position. Monophyly of the genus Nephius , although never previously questioned or tested, is herein corroborated for the first time, even though using only two among its 11 nominal species. Another new and definite result of this analysis (as compared to Grebennikov 2018b) is the strongly supported rejection of the taxonomically implied hypothesis that the tribe Stromboscerini (including morphologically odd Nephius ) is a clade. This result is not surprising, since the genus has already been explicitly removed (as Anius ) from the rest of the tribe in a little-known work by Voss (1940). The sister relationship between Nephius and the clade formed herein by the rest of Stromboscerini and the genus Dryophthorus ( Fig. 3 View FIGURE 3 , this clade was first recovered in Grebennikov 2018b) does not necessarily reflect the reality and is perhaps an artifact of sparse sampling. The sister group of Nephius is presently unknown and cannot be adequately hypothesised. No formal taxonomic action of removing Nephius from the tribe Stromboscerini is herein taken, since the type genus, Stromboscerus , might itself be unrelated to the rest of the tribe.

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