Pseudoechthistatus Pic, 1917

Bi, Wen-Xuan & Lin, Mei-Ying, 2016, A revision of the genus Pseudoechthistatus Pic (Coleoptera, Cerambycidae, Lamiinae, Lamiini), ZooKeys 604, pp. 49-85 : 50-53

Taxon classification Animalia Coleoptera Cerambycidae

Pseudoechthistatus Pic, 1917

Pseudoechthistatus Pic, 1917: 6. Type species: Pseudoechthistatus obliquefasciatus Pic, 1917, by monotypy.

Pseudechthistatus (sic): Breuning 1942: 132; Breuning 1961: 318; Löbl and Smetana 2010: 286.

Pseudoechthistatus : Gressitt 1951: 349; Chiang et al. 1985: 104.

Redescription.

Body elongate, medium sized (ca. 15.0-25.0 mm long). Head subequal to the pronotal width at base. Eyes coarsely faceted, strongly emarginate; lower lobe small, weakly prominent, subequal to or slightly longer than width. Frons wider than long. Antennal tubercles moderately prominent and separated. Antennae long, ca. 1.6-2.0 times (in male) or 1.2-1.4 times (in female) as long as body length; scape moderately long, apical cicatrix completed, the 3rd antennomere longest, ca 1.5-1.8 times as long as scape, 4th antennomere slightly longer than (in male) or subequal to (in female) scape, 4th to 10th successively shortened and narrowed, last antennomere slightly longer than penultimate; basal antennomeres (3-4 in male, 4-7 in female) distinctly fringed beneath. Both maxillary and labial terminal palpomeres fusiform. Pronotum cylindrical, subequal to or slightly longer than width at base; with two indistinct transverse grooves at the anterior and posterior margins; disk with a rugose longitudinal ridge, slightly raised medially, both sides with a developed or reduced, longitudinal pubescent band; with a lateral spine moderate long and acute apically at anterior middle of each side; prosternal intercoxal process narrow, slightly emarginate at apex, lower than coxae; procoxal cavities closed posteriorly; mesosternal intercoxal process without tubercle and obliquely sloped in lateral view; mesocoxal cavities open externally to mesepimera; metasternum short to moderately long, ca 1.0-1.8 times as long as mesosternal length. Scutellum broadly rounded posteriorly. Elytra elongate, ca. 1.8-2.2 times as long as humeral width, widest at the middle or at humeri or subparallel-sided in basal half, gradually to strongly narrowed after the middle, rounded or obliquely truncated to acute apically; disk finely to coarsely punctured, granules absent or moderately to strongly developed, with few erect or suberect setae; each elytron conspicuously with a moderate to large sized, median, moderately to strongly raised, glabrous tubercle subbasally (Figs 38-40); generally provided with three light pubescent markings: the first annular marking around the subbasal tubercle (subbasal annular marking), the second band complete or discontinuous, nearly transverse to strongly oblique, across the elytron near middle (middle band), the third stripe longitudinally near apical one-fourth toward elytral apex (preapical stripe). Hindwings developed to highly reduced. Legs long and slender, protibia with a subapical tooth beneath (weak in females), mesotibia with a subapical oblique groove externally, tarsus four segmented. Tarsal claws free, divaricate to moderately divergent.

Male genitalia. Tergite VIII (Figs 49-55, a) trapezoidal, truncated to slightly emarginated apically, with moderately long setae. Tegmen (Figs 49-55, b, c) in lateral view moderately curved, rhombic in shape and widest at middle or behind middle in ventral view; lateral lobes moderately slender, ca. one-fourth of total length of tegmen, which moderately provided with long setae on apex. Median lobe (Figs 49-55, d, e) slightly shorter than tegmen; moderately curved in lateral view; apex rounded to subacuminate in antero-dorsal view. Endophallus in everted condition (Figs 58-64) S-shaped, long and slender, subequal to or slightly longer than triple length of median lobe; BPH, MPH and APH well defined, crescent shaped sclerites (cs) present, MPH subdivided into MT, CT and PB by a constriction; the length of MT ca. 2.0-2.5 times as long as the length of BPH, CT slightly shorter than PB, the combined length of CT and PB subequal to the length of BPH and slightly shorter than median lobe; BPH hardly swollen apically; PB cylindrical at base with developed anterior bulb, CT developed, basal swelling (bs) strongly swollen ventrolaterally or with distinct lateral tubercles (ltc), slightly swollen posterodorsally, MT with ventral swelling (vs) generally rudimentary; APH variable, moderately to strongly constrictive or moderately swollen, apical bulb (ab) sclerotized apically or at least in ventral side (when APH strongly constrictive), apical furrow (af) with internal membrane (im) well developed (Fig. 58b); apical bulb (ab), apical part of CT and PB, ventral side of basal swelling (bs) provided with spicules; ejaculatory ducts paired; gonopores (gn) situated near apex of apical bubble (bb), a pair of rod-like sclerite generally absent.

Female genitalia. Setae of sternites VIII sparse and short, apical ones longer (Fig. 56f). Distinct lateral notch present and positioned behind the distinct pigmented patch on sternites VIII (Fig. 56f). The paraproct is very short and devoid of baculi; the coxite lobes are very long and bear small styli (Figs 56g, 56h). Spiculum ventrale (Fig. 56f) longer than abdomen, slightly expanded apically. Female genital track (Fig. 57) with well-developed vaginal plate (VP); bursa copulatrix (BC) moderately long, spermathecal duct attached before middle of bursa, compose of a thin long duct and an expanded and curved apical part. Spermathecal capsule (SP) and gland (SPGL) positioned on apex of spermathecal duct (SPD). Spermathecal capsule strongly sclerotised, crutch shaped (Fig. 57a), apical part more than twice of basal part in length, the whole capsule larger than the expanded apical part of spermathecal duct. Spermathecal gland is an elongate membranous sac, with its length variable but always more than triple length of spemathecal duct.

Distribution

(Map 1). China, Myanmar, Vietnam.

Remarks.

This genus is unique with a conspicuous raised subbasal tubercle on each elytron among the oriental genera of Lamiini . It is superficially resembles Mesechthistatus Breuning, 1950, but immediately distinguished by antennal scape with a complete cicatrix, basal antennomeres distinctly fringed beneath, pronotum with a rugose median longitudinal ridge, and elytra lacking lateral carinae. Pseudoechthistatus shares some characters with Paraleprodera Breuning, 1935: antennae normal (without swollen), scape with a complete cicatrix, basal antennomeres distinctly fringed beneath, pronotal lateral spine present, prosternal process normal (not angularly enlarged between coxae), protibia with a subapical tooth beneath (at least in male), and similar to some species of Paraleprodera (e.g. Paraleprodera diophthalma , Paraleprodera bisignata , Paraleprodera bigemmata ) by possess the subbasal tubercle (or tubercles) on each elytron, but is distinguished by elytron with single large raised subbasal tubercle, pronotum with a rugose longitudinal ridge medially, endophallus with CT developed, swollen in dorsal and ventral sides and APH without a pair of U-shaped sclerite (the latter with the subbasal tubercle composed of small granules, CT of endophallus simple and APH with a pair of U-shaped sclerite (Figs 67f, 68g)). It is most close to another group of Paraleprodera (e.g. Paraleprodera carolina , Paraleprodera itzingeri , Paraleprodera mesophthalma ) with regard to the overall form, especially the presence of the median rugose longitudinal ridge on pronotum, the shape and proportion of the endophallus and the absence of the U-shaped sclerite on APH. But it is distinguished from them by elytron with a subbasal tubercle, endophallus with CT swollen postero-dorsally and PB cylindrical at base (without a ventral tubercle (vbt) (Figs 65, 66)).

Breuning (1942) mentioned that Pseudoechthistatus has the claws “divergent” (divergence less than 90°). According to our observation, the claws of this genus are free, and most species have them “divaricate” (divergence exceeding 100°), only some species or individuals (especially of the type species) have the claws in transitional (divergence between 80° to 90°).

The subbasal tubercle on each elytron of this genus is usually single and complete. However, a few individuals (two of nearly one hundred specimens) have the subbasal tubercle separated by several grooves (Fig. 29). This was considered an aberration and is not included in the generic diagnosis, but it may indicate that the single subbasal tubercle have originated from several converging small tubercles (or granules) as present in e.g. Paraleprodera diophthalma Pascoe .

The type species of this genus is flightless, having a shortened metasternum (subequal to mesosternum in length), constricted humeri and reduced hindwings. These three related structures were considered as generic characters by Breuning (1942). However, Pseudoechthistatus birmanicus with the normal metasternum length (metasternum / mesosternum length ratio ca. 1.8) and normal hindwings, while Pseudoechthistatus acutipennis is transitional (metasternum / mesosternum length ratio ca. 1.5). Therefore, at least for this genus, the shortened metasternum should be treated as an infrageneric apomorphy.

Pseudoechthistatus was placed originally in the tribe Phrissomini by Breuning (1942), and this was followed by Gressitt (1951) and Breuning (1961). Sama (2008) synonymized Phrissomini with Lamiini . Löbl and Smetana (2010) placed the genus Pseudoechthistatus under the tribe Monochamini which was separately used from Lamiini . In this paper, we place it under Lamiini and follow Breuning (1943, as Agniini ), Gressitt (1951), Breuning (1961) and Ohbayashi and Niisato (2007) who consider Lamiini to include Monochamini (sensu Löbl and Smetana 2010).