Palpoxena hajeki Bezděk, 2022

Bezděk, Jan, 2022, Palpoxena hajeki sp. nov., a remarkable new species from Malaysia (Coleoptera Chrysomelidae: Galerucinae), Zootaxa 5222 (4), pp. 378-384 : 379-384

Palpoxena hajeki Bezděk , sp. nov.

( Figs 1–12 )

Type locality. Malaysia, Perak, Cameron Highlands , at 04°22.2´N 101°20.0´E .

Types. Holotype: ³ ( NMPC), “MALAYSIA, Perak / Cameron Highlands / Batu (= Mile ) 19 vill. env. / 04°22.2´N, 101°20.0´E, 590 m / Jiří Hájek leg. 5.- 15.v.2009 [w, p]” . Paratypes: 8 ³³ ( NMPC), same data as holotype; 18 ³³ ( JBCB), “MALAYSIA W, 2013 / KELANTAN, Kg. Tunku / Mt. Noring Timur, 1200m / 150 km S of JELI, 21.ii.- / 14.iii. P. Čechovský leg. [w, p]”; 1 ³ ( JBCB), “MALAYSIA, 6- 12.iii.1998, / Perak prov., ca 1800 m, / G. KORBU mt., Banjaran / Titi Wangsa mts. , ca 30 km / NEE of IPOH, leg. M. Just [w, p]”; 1 ³ ( BMNH), “ Malay Peninsula [w, h] // Ex F. M. S. / Museum. / B. M. 1955-354. [w, p]”; 1 ³ ( BMNH), “MALAYSIA Perak / 50km NE Gerik / 5°36´N 101°32´E / 1100m, April 2015 / BMNH(E)2016-44 [w, p]”; 1 ³ ( NHRS), “Malaysia Pahang Fraser´s / Hill 1200m 25.3.1992 light / B Gustafsson, H et H Hippa / G Sellerholm [w, p] // NHRS-JLKB / 000023115 [w, p]”; 1 ³ ( USNM), “MALAYSIA: Pahang; / Frasers Hill / 29 Aug- 2 Sep 1990 / C. L. Bellamy [w, p]”. The type specimens are provided with one additional printed red label: “HOLOTYPUS [or PARATYPUS], / Palpoxena / hajeki sp. nov., / J. Bezděk det. 2022” .

Description. Measurements. Males: 9.9–11.0 mm (holotype 10.9 mm). Dorsal side elongate oval, convex, glabrous. Head, pronotum and elytra reddish brown, ventral side reddish brown in lighter shade, mouthparts, antennae and legs yellow, apices of mandibles black.

Male (holotype, Fig. 1 ). Labrum transversely suboval, posterior margin straight with subtriangular protrusion in middle covered by long setae, surface convex, with shallow longitudinal impression in middle, lustrous, covered with fine punctures, glabrous (except pair of isolated setae in middle of both halves of labrum. Anterior of head deeply excavate ( Figs 8–12 ). In lateral view, cavity forms deep oval notch almost touching eyes, withlateral hooklike process. Posterior cavity margin widely and shallowly triangularly concave. Internal cavity structures contain pair of oblique and twisted lamellae in anterior part and pair of large twisted tufts of setae. Posterior cavity margin and margins of lateral process with long pale setae. Interantennal space 1.43 times as wide as transverse diameter of antennal socket. Interocular space wide, 2.05 times as wide as transverse diameter of eye. Frontal tubercles oblique, axe-shaped, elevated, finely microsculptured, separated by deep notch. Vertex glabrous, finely microsculptured, almost impunctate, separated from frontal tubercles by deep oblique line, surface with shallow impressed longitudinal line in anterior half.Antennae filiform, 0.90 times as long body, length ratios of antennomeres in sequence from first equals 100-16-104-100-92-88-84-76-72-60-60 (100 = 1.25 mm), densely covered by short recumbent setae, ventral sides of antennomeres III–XI covered also with longer erect setae which gradually shorten towards antennal apex. Penultimate maxillary palpomere moderately enlarged, ultimate palpomere conical and inserted into penultimate.

Pronotum transverse, 1.55 times as wide as long, semiopaque, glabrous, widest in anterior third, covered with fine punctures (more prominent in anterolateral area) and microsculpture. Surface moderately convex, with wide transverse impression at posterior half, slightly shallower in middle.Anterior margin slightly concave, lateral margins slightly rounded at anterior half, convergent and straight posteriorly, posterior margin moderately rounded, slightly sinuate in middle. Anterior margin unbordered, lateral and posterior margins distictly bordered. Anterior angles swollen, posterior angles nearly rectangular, each angle with setigerous pore bearing a long pale seta. Scutellum subtriangular, with widely rounded apex, impunctate, covered with very fine microsculpture, glabrous.

Elytra suboval, 1.41 times as long as wide (measured at widest, in posterior third) and 0.62 times as long as body, with shallow transverse impression at anterior third and slightly impressed suture between transverse impression and scutellum. Surface semiopaque, glabrous (except several pale setae on apical slopes) densely covered with small confused punctures and extremely fine microsculpture. Humeral calli well developed. Epipleura uneven, glabrous (except several setae near elytral apex), widest at anterior third, gradually narrowed towards elytral apex. Macropterous.

Prosternum and mesosternum lustrous, glabrous and impunctate, metasternum covered with sparse puncture and long pale setae, abdomen semiopaque, covered with dense punctures and shorter setae ( Fig. 2 ). Posterior margin of last abdominal ventrite with two v–shaped incisions ( Fig. 8 ).

All legs densely covered with short recumbent setae. Protarsomere I wide, suboval, convergent towards base, distinctly wider than small and triangular protarsomere II, length ratio of protarsomeres I–III and V equals 100-43-43-78 (100 = 0.70 mm). Venter of protarsomere I with large oval sensilla patch covering about basal two thirds of surface ( Fig. 6 ). Mesotarsomere I wide, parallel, as wide as triangular mesotarsomere II, length ratio of mesotarsomeres I–III and V equals 100-50-50-78 (100 = 0.70 mm). Venter of mesotarsomere I with oval sensilla patch covering about basal half of surface ( Fig. 7 ). Metatarsomere I narrow, slightly convergent towards base, length ratio of metatarsomeres I–III and V equals 100-27-27-55 (100 = 1.10 mm). Claws appendiculate.

Penis ( Figs 3–5 ) elongate, 7.20 times as long as wide, subparallel, widest at apical 2/5, apexgradually narrowed to triangular tip, apex with lentil-shaped aperture, tectum long, lanceolate, with apex ending at basal margin of aperture. In lateral view, penis moderately curved, apex slightly bent. Ventral side with distinct angulation at apical 2/5. Ventral side with long groove narrowed at apical 2/5 by two wide subtriangular teeth.

Female unknown.

Differential diagnosis. The 21 Palpoxena species distributed in the easternmost parts of India, South-East Asia and Sunda Archipelago pertain to the Palpoxena laeta species group, characterised by more or less expanded penultimate maxillary palpomere in males. In some species the penultimate maxillary palpomere is extremely enlarged (e.g. P. laeta Baly, 1861 or P. shayakhmetovae Kizub, 2016 ). The elytra of almost all species in Palpoxena laeta species group are at least partly dark (usually metallic blue, green or black with reddish extreme apex). Rarely the elytra are bright metallic green without reddish apex ( P. antonini Bezděk, 2017 from Borneo), or red with basal half metallic blue as in P. bipartita (Jacoby, 1879) from Sumatra, or red with apical third (and sometimes also basal third) black as in Malayan and Indonesian species P. variabilis (Jacoby, 1886) and P. jacobyi (Baly, 1888) . A completely reddish dorsum with slight metallic tint is known only in P. eximia (Baly, 1879) from Assam and P. hajeki sp. nov.

Palpoxena males are also characterised by modifications of the anterior part of head which is distinctly impressed or excavate. Usually the impression is shallow with base of the pit visible. A deep cavity, combined with the presence of large tufts of setae, is known in only few species. In P. sabahensis Mohamedsaid, 1997 from Borneo, the posterior margin of head excavation is provided with two distinct processes directed anteriorly ( Fig. 17 ), and elytra are metallic blue or green with reddish apex. Palpoxena coomani (Laboissière, 1933) from Vietnam has labrum transverse, relatively narrow with both anterior and posterior margins widely concave ( Fig. 18 ), male protarsomere I narrow, not expanded, and dorsum completely black. Palpoxena caeruleipennis (Baly, 1888) from former Indochina has posterior margin of labrum rounded with deep narrow notch in the middle ( Fig. 19 ), male antennomere I distinctly pronounced to small apical tooth, male protarsomere I only slightly widened, and dorsum with pale brown to red head and pronotum, and elytra metallic blue with extreme apex pale. Palpoxena barbata (Baly, 1879) from Assam has reduced tufts of setae in the cavitous anterior part of head ( Fig. 20 ) and violet-black elytra. Palpoxena hajeki sp. nov. differs from the above species by the combination of following characters: labrum transversely suboval with posterior margin straight with subtriangular protrusion in the middle, male antennomere I not modified, protarsomere I widely suboval, the deeply excavate anterior part of head with a pair of large twisted tufts of setae, and dorsum completely reddish.

In coloration and head structure, P. hajeki sp. nov. is most similar to P. eximia (Baly, 1879) from Assam ( Figs 13–16 ). Both species share completely reddish dorsum with slight metallic tint and deeply excavate anterior part of head with large twisted tufts of setae. Male of P. eximia has small eyes with interocular space extremely wide (4.00 times as wide as the transverse diameter of eye), posterior margin of head cavity with two paler small oblique lamellae, and sides of cavity process wide and triangular. Males of P. hajeki sp. nov. have eyes at least two times larger with interocular space only 2.00 to 2.20 times as wide as the transverse diameter of eye, posterior margin of the head cavity without lamellae, and the lateral cavity process narrower and hook-like.

Distribution. Malaysia (Perak, Kelantan).

Etymology. Dedicated to my dear friend Jiří Hájek, a specialist in water beetles, who collected part of the type series.

Figures

FIGURES 1–8. Palpoxena hajeki Bezděk, sp. nov. 1—holotype in dorsal view; 2—paratype in ventral view; 3—penis in dorsal view; 4—penis in lateral view; 5—penis in ventral view; 6—male protarsus in ventral view; 7—male mesotarsus in ventral view; 8—last abdominal ventrite.

FIGURES 9–12. Male head of Palpoxena hajeki Bezděk, sp. nov. 9—dorsal view; 10—lateral view; 11—frontal view; 12— oblique view.

FIGURES 17–20. Head of Palpoxena males in frontal view. 17—P. sabahensis Mohamedsaid, 1997; 18—P. coomani (Laboissière, 1933); 19—P. caeruleipennis (Baly, 1888); 20—P. barbata (Baly, 1879), holotype. Photo of P. barbata by Keita Matsumoto (BMNH).

FIGURES 13–16. Palpoxena eximia (Baly, 1879), holotype. 13—dorsal view; 14—frontal view; 15—head in detail; 16— labels. Photos by Keita Matsumoto (BMNH).