Xylodes (Diegous) korinae Zahradník & Trýzna, 2023

Zahradník, Petr, Trýzna, Miloš & Razafindranaivo, Victor, 2023, A new species of Xylodes Waterhouse from Madagascar, with a key to the genera of the tribe Ptinini from Madagascar, Mascarenes and adjacent regions, and a key to species of Xylodes, subgenus Diegous (Coleoptera: Ptinidae), Zootaxa 5330 (1), pp. 93-105 : 95-102

Xylodes (Diegous) korinae Zahradník & Trýzna sp. nov.

( Figs 1–8 , 26–28 )

Type material. Holotype (male): Madagascar, Anjozorobe forests [= Anjozorobe-Angavo protected harmonious landscape], circuit Bambou, 18°24´54.9´´S, 047°56´45.2´´E, 15.-19.i.2019, 1328 m, primary forest, M. Trýzna lgt. ( FGMRI) . Paratypes (2 males, 3 females): the same data as holotype (1 male in BMNH; 1 male, 1 female in FGMRI; 1 female in MTDC; 1 female in TKPC) .

Description. Male (holotype). General appearance. Body ( Fig. 1 ) shortly sub-oval, small; body length 2.1 mm, the greatest width (in humeral part of elytra) 1.2 mm. Humeri well developed, sides of elytra almost parallel, apical third of elytra rounded. Pronotum distinctly narrower than the base of elytra ( Fig. 2 ). Antennae robust ( Figs 1, 3, 5 , 8 ).

Coloration and vestiture. Body ( Fig. 1 ) rusty brown, with reddish tinge. Antennae, palpi and legs the same colour, but without reddish tinge. Pubescence of head very sparse, almost absent, short, recumbent. Antennomeres I–IX with long, dense, semierect setae, antennomeres X–XI with short dense appressed setae ( Fig. 8 ).

Surface of pronotum ( Fig. 2 ) shining, densely and coarsely tubercule punctuated, punctures almost touching, covered by dense, long, erect dark setae. Pronotum with four white spots on lateral sides, two elongated and more or less interrupted in posterior part, and two irregular spots in interior part. Elytra ( Figs 1, 5 ) shining, with three types of pubescence: the first on striae, arranged into rows, sparse, erect, very long, yellowish-gold; the second arranged similarly on interstriae, but half the length; the third consisting of white scales arranged into spots. Each elytron with five distinct white spots of scales: two on elytral intervals IV on sub-basal and preapical part, one on elytral interval VII and VIII in median part, one on elytral interval VIII in sub-basal part, and last one on elytral interval IX in preapical part ( Figs 1, 5 ). Episternum covered with distinct white scales. Antennae and pronotum covered with light-brownish setae.

Structure. Head ( Fig. 2 ) densely and coarsely punctured, punctures almost touching. Eyes longitudinally slightly elliptical, weakly convex, glabrous. Frons 3.0 times wider than width of eye in dorsal view.

Antennae ( Figs 1, 3 , 8 ) robust, with eleven antennomeres, without antennal club or enlarged last three antennomeres, shorter than body; scapes practically touching each other at the base. Antennomere I (scape) robust 1.1 times longer than wide. Ratio length to wide of other antennomeres is following—II 1.5, III 1.2, IV 1.3, V 1.2, IV 1.6, VII 1.5, VIII 1.6, IX 1.3, X 1.5 and XI 2.5. With the exception of the first and last antennomeres, the other antennomeres are similar in length and width. The ratio of length of antennomeres I to XI is as follows—1.0: 1.1: 0.9: 0.9: 0.8: 1.0: 1.0: 1.1: 0.9: 0.9: 1.5; similarly the width of individual antennomeres I—XI (mostly with only very fine differences) is as follows—1.0: 0.8: 0.8: 0.8: 0.8: 0.7: 0.8: 0.8: 0.8: 0.7: 0.7.

Pronotum ( Fig. 2 ) slightly transverse, ratio wide to length 1.1, widest in central part, disc of pronotum with one blunt bump, with more or less distinct lateral depressions on the sides of central bump, only base of pronotum with transverse depression, strongly emarginated posteriorly.

Elytra ( Fig. 1 ) with distinct humeri. Ratio of length to width 1.5, apical third of elytra rounded. Each elytron with eleven striae consist of rounded punctures with visible bottom, interstriae very narrow, narrower than punctures.

Scutellum small, as long as wide, rounded.

Legs ( Fig. 1 ) slim and relatively long, all legs similar, femora robust, wider than tibiae, tibiae 1.5 times as long as tarsi. Tarsomeres I–IV the same width, tarsomere V 2.6 times narrower than previous. Tarsomere II 1.5 times shorter than tarsomere I, tarsomere III and IV 1.3 times shorter than tarsomere II, tarsomere V 1.2 times longer than tarsomere II. Claws small, interior part without teeth.

Abdomen ( Fig. 4 ). Ventrite I in the middle with short blunt wide promontory, twice as long as its width at its base and twice as long as ventrite I at its narrowest point. The ratio of ventrites I to V (measured at the shortest ventrite length, referred to ventrite I) is as follows—1.0: 3.6: 3.6: 1.6: 2.4.

Male genitalia ( Fig. 6 ) well sclerotised. Aedeagus slender, with more or less straight parameres, these almost bare, covered with only short indistinct setae in apical and preapical part. Median lobe shorter than parameres, distinctly slender, its apex extending in narrow flagellum.

Female genitalia and surrounding structures ( Fig. 7 ). Hemisternites well sclerotised, but delicate, less than half the width of segment VIII. Apex of hemisternites divergent. Segment VIII distinct, transverse, distinctly wider than its length. Tergite VIII only at base as wide as sternite VIII, then conspicuously convergent, distinctly bilobed, inner angles form right angle, anterior margin covered with several inward directed setae. Sternite VIII broadly convex in middle part, anterior margin with only delicate sparse setae, proximal apodeme long and slender.

Female. Without distinct sexual dimorphism.

Variability. Body length 2.0– 2.1 mm, differences in greatest width are indistinct, almost undetectable. No other differences are detected.

Differential diagnosis. The new species, Xylodes (Diegous) korinae sp. nov., belongs to a group of three species, together with X. (D.) excavaticollis ( Fig. 11 ) and X. (D.) soarezicus ( Fig. 14 ), which have only white spots on elytra. The other above mentioned two species have different arrangement of spots (compare Figs 1 , 11 and 14 ). For other morphological characters see the key below.

Etymology. Matronym, dedicated to the wife of the second author, Korina Kudrnová (Děčín, Czech Republic), a participant on some Madagascan entomological expeditions, for her unlimited support of our entomological work.

Collecting circumstances. The new species comes from Anjozorobe-Angavo protected harmonious landscape (IUCN category V) in the Central Highlands, Central Madagascar. This protected area is dominated by a humid and sub-humid climate. The Anjozorobe-Angavo forests represent one of the last remnants of natural forest in the Central Highlands. This area is characterized by a relatively intact medium altitude moist evergreen forest with a canopy height of 10–20 metres ( Fig. 26 ) (see also Goodman et al. 2018).

All specimens from the type series were collected on the dead wood of a deciduous tree inside the forest on an elevated site at altitude 1328 m a.s.l. A partially broken smaller branch ( Fig. 27 ) with dry leaves was placed about 1 m above the ground. A simple method was used: strong beating of the leafy part of the branch using a 40 cm entomological net. An important detail was the repetition of this beating, because more specimens were obtained this way (six in total). Repeated collection the next day on the same branch did not yield any further specimens, and nor were these beetles found on similar branches in the immediate vicinity.

Distribution. C Madagascar, Antananarivo province ( Fig. 28 ).

Figures

FIGURE 28. Type locality of Xylodes (Diegous) korinae sp. nov.

FIGURES 1–5. Xylodes (Diegous) korinae sp. nov., male holotype. 1, dorsal habitus; 2, pronotum and head with scape and pedicel in dorsal view; 3, right antenna in dorsal view; 4, abdomen in ventral view; 5, lateral habitus.

FIGURES 6–8. Xylodes (Diegous) korinae sp. nov. 6, 8, male holotype; 7, female paratype; 6, aedeagus in dorsal view; 7, female genitalia and surrounding structures in dorsal view; 8, right antenna in dorsal view. Scale bars in mm.

FIGURES 26–27. Xylodes (Diegous) korinae sp. nov., Anjozorobe-Angavo forest, type locality. 26, collecting site, overall view with relatively intact medium altitude moist evergreen forest; 27, microhabitat of the type locality, detail of forest with the canopy height 10–20 metres with sparse coppices of small diameter trees.

FIGURES 9–14. Species of Xylodes (Diegous), dorsal habitus. 9, X. (D.) caroli (male); 10, X. (D.) elongatus (female); 11, X. (D.) excavaticollis (male); 12, X. (D.) lineatus (male); 13, X. (D.) pauliani (male); 14, X. (D.) soarezicus (male). From Bellés 1987, 1988a.