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Zenodo
2022
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| Online Access: | https://doi.org/10.5281/zenodo.7409409 |
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- <p><b><b>Genus <i>Disconius</i> Skejo, Pushkar et Tumbrinck gen. n.</b></b></p><p><b>Type species</b>: <i>Discotettix shelfordi</i> Hancock, 1907 (= <i>Disconius shelfordi</i> <b>comb. n.</b>).</p><p><b>Justification for the establishment of the new genus.</b> Head and pronotum morphology of <i>Disconius shelfordi</i> <b>comb. n.</b> differs too widely from other <i>Discotettix</i> species for it to be regarded as a member of the latter genus, so a new monotypic genus is established for this species, <i>Disconius</i> Skejo, Pushkar et Tumbrinck <b>gen. n.</b> Fastigial horns are lower, while the bifurcation of the frontal costa, lateral ocelli and antennal grooves have a much higher position than in any <i>Discotettix</i> species. Unlike <b>FM</b> and high pronotal projections in <i>Discotettix</i>, <i>Disconius</i> <b>gen. n.</b> lacks elevated <b>FM</b> (present as a small tubercle on the anterior pronotal margin); <b>FL1</b> and <b>FL3</b> are not strongly projected forwards as in <i>Discotettix,</i> and the strongest projections are <b>ML</b> of the shoulders area (similar to <i>Tegotettix</i>). The new genus is assigned to the subfamily Scelimeninae and to the tribe Discotettigini <b>stat. resurr.</b> on the basis of the width of the vertex (wide) and the weak elevation of the lateral carinae of the vertex; the typical arrangement of the pronotal projections (<b>FM</b>, <b>MM</b>, <b>MML</b>, <b>ML</b>); armed femora; and not widened hind tibiae and tarsi. The new genus is similar and likely related to the genera <i>Tegotettix</i> and <i>Discotettx</i>, but also superficially resembles <i>Falconius</i>. From <i>Tegotettix</i> and <i>Falconius</i> it can be easily distinguished by widened antennal segments, while from <i>Discotettix,</i> to which it was formerly assigned, it can be distinguished by a number of characteristics stated above. Molecular and comprehensive morphometric comparison of <i>Disconius shelfordi</i> <b>comb. n.</b> with large series of <i>Discotettix, Tegotettix,</i> and <i>Falconius</i> specimens is needed in the future, to elucidate the evolution of this curious taxon.</p><p><b>Composition and distribution.</b> A monotypic genus, including only <i>Disconius shelfordi</i> (Hancock, 1907) <b>comb. n.</b>, known only from northern Borneo.</p><p><b>Etymology</b>. Because of the former taxonomic placement within <i>Discotettix</i>, and because of the superficial similarity to certain members of the genus <i>Falconius</i> due to its slender appearance and the shape of the pronotal projections, the names of two genera were combined into <i>Disconius</i>, meaning that this is both <i>Discotettix</i> -like and <i>Falconius</i> -like genus.</p><p><b>Differential diagnosis</b>. For the comparison with <i>Discotettix</i>, from which <i>Disconius</i> <b>gen. n.</b> has been removed, see the justification above, as well as the diagnosis of the genus <i>Discotettix</i>. From the genus <i>Tegotettix</i> (including <i>T. armatus</i> and <i>T. bufocrocodil</i>) the genus can be separated by head morphology <b>—</b> lateral ocelli positioned higher, frontal costa short before the bifurcation, vertex not bearing high horns, antennae with widened subapical antennal segments, and tibiae not armed. From the genus <i>Falconius</i>, <i>Disconius</i> <b>gen. n.</b> can be separated by the arrangement of the pronotal projections, the lack of flattened hind tarsi, and by widened apical segments of the antennae.</p><p><b>Description.</b></p><p><b>Head</b>. Frontal costa bifurcation between the compound eyes; scutellum narrower than scapus; upper margin of the antennal groove above the lower margins of the compound eye; lateral (paired) ocelli between the compound eyes; eyes protruded above the vertex Antennae 15-segmented (1 st scapus; 2 nd pedicel; basal 3 rd –7 th elongated; central or subapical 8 th weakly compressed, 9 th elongated and strongly compressed; 10 th compressed; apical segment 11 th small; apical 12 th –15 th reduced, smooth and cylindrical). Vertex wider than a compound eye. Lateral carinae of the vertex in frontal view weakly elevated, medial carina of the vertex visible, anterior margin of the vertex slightly indrawn.</p><p><b>Pronotum.</b> Body robust, the ratio of the humeral angles’ width to the prozonal width more than 3.5. Anterior margin of the pronotum truncated or slightly excised, without strongly elevated <b>FM</b>; prozonal carinae distinct and parallel; extralateral carinae strong, with <b>FL2</b> as a small elevation; <b>FL3</b> weak; medial carina continuous along all the pronotum, tuberculated; <b>MM</b> high compressed elevations; <b>PMLs</b> and <b>MMLs</b> distinct; <b>MML2</b> well developed as a high tubercle; <b>ML</b> triangular protrusion with a tubercle on its tip; interhumeral carinae distinct; interscapular area distinct and with parallel margins; lateral area as wide as the interscapular area; humero-apical, humeral, and lateral carinae with triangular or spine-like projections; <b>VL</b> protruded as a weak spine; paranota triangular; dorsum of the pronotum without <i>Discotettix —</i> characteristic net-like elevations, but still rough.</p><p><b>Legs.</b> Fore and mid femora carinated above, armed with a few small teeth on the dorsal and ventral margins; the dorsal margin of hind femora strongly armed; ventral margin with undulated carinae; the external surface of the hind femora with recognizable transverse ridges; hind tibia finely, densely serrate with numerous small teeth, but without large teeth; distal part of the hind tibia slightly widened, proximal tarsal segment slightly widened; first and the third tarsal segments of the hind legs almost equal in length; pulvilli typical for Scelimenini —first two angular and the third obtuse.</p>