Pseudohomonyx continentalis Yang & Pathomwattananurak, 2023

Yang, Qiao-Zhi, Geshev, Georgi & Pathomwattananurak, Wuttipon, 2023, A new species of the genus Pseudohomonyx Arrow, 1908 (Coleoptera: Scarabaeidae: Dynastinae) from Malaysia and Thailand, with first description of P. apoensis Miyake & Yamaya, 1997 male and a catalogue of the genus, Zootaxa 5361 (1), pp. 114-124 : 115-117

Pseudohomonyx continentalis Yang & Pathomwattananurak , new species

( Figs. 1A–1E )

Type material (2♁♁, 1♀). Holotype: Malaysia: ♁ ( CAU), “ Genting Highlands, Pahang State, Malaysia , IV.2022, local collector leg.” Paratypes: Thailand: 1♁ ( THNHM), “S Thailand: Surat Thani Prov., Ban Na Sarn Dist., Plai Nam Subdist., 15–28 April 1986, J. Nabhitabhata leg. // THNHM-I-10375”; 1♀ ( THNHM), “larva collected in 2023, Nopphitam Dist., Nakhon Sri Thammarat Prov. , Chayaphol Photaworn leg., adult emerged 19.V.2023.”

Description (holotype male). General ( Figs. 1A–1B ): Body dark brown, surface mildly shiny; ventral surface covered with dense, long reddish-brown setae. Head ( Fig. 1C ): Surface mostly dark brown. Clypeus with dense transverse rugopunctures throughout; clypeal apex almost flat; lateral and apical margins of clypeus bordered. Frons with transverse rugopunctures throughout. Transverse carina separating frons and clypeus indicated by an obtuse tubercle at each side. Mandible at outer margin rounded near apex, almost straight at middle. Pronotum ( Fig. 1C ): Surface dark brown; sparsely micropunctate throughout, only with a few slightly larger punctures sparsely distributed near lateral margin. impression absent. Side roundly curved, widest near posterior one-fourth; all margins emarginate except narrowly interrupted in lateral margin; anterior margin without any tubercle at middle. Anterior and posterior angles rounded. Scutellum: Surface dark brown; sparsely punctate near base. Elytra: Surface mostly dark brown, except dark reddish sutural ridge; with sparse micropunctures and dense, round, large punctures in striae. Sutural striae narrow, deeply sulcate; other striae wider, even intervals slightly wider than their adjacent odd intervals. Intervals micropunctate, with dense, larger punctures on fourth and sixth intervals posteriorly. Apex densely punctured. Humeral and apical calli obtuse. Epipleuron of elytron moderately dilated horizontally from base to posterior one-fifth, widest behind middle. Metasternum: Surface with dense setae; punctures small and dense close to sides; median region with sparser and smaller, with a longitudinal depression. Abdomen: Pygidium with dark brown surface, slightly convex, with very dense punctures throughout. Abdominal ventrites with dark brown surface, with reddish anterior margin; with sparse micropunctures, larger punctures near base and longitudinal midline, and a row of punctures with long setae at sides. Legs: All legs dark brown, slightly more reddish than other parts of the body. Protibia tridentate, protarsi very strongly thickened, inner protibial claw very strongly enlarged and elongated. Parameres ( Figs. 1D–1E ): In caudal view ( Fig.1D ), slender and symmetric; without any setae; outer sides with a pair of short, acute, outward and strongly backward processes at posterior one-sixth; inner sides simply curved; apex rounded; in lateral view ( Fig. 1E ), apex slightly bent downward.

Paratype (male). Characters stable, except punctures on fourth and sixth intervals sparser, lesser in number ( Fig. 2A ).

Paratype (female). Characters mainly stable, except color much more reddish (it died two days after emerging before full melanization, thus the color is likely not its natural color); transverse carina separating frons and clypeus absent; punctures on fourth and sixth intervals sparser, lesser in number; protarsi not thickened, inner protibial claw not enlarged and elongated ( Fig. 2B–2C ).

Measurements. Body length: male 19.5–20.0 mm (holotype 20.0 mm), female 20.7 mm; body width: male 10.3–11.0 mm (holotype 10.3 mm), female 11.6 mm.

Diagnosis. This species is relatively unique in its appearances and can be easily distinguished from all other species of the genus by absent of the frontal impression and frontal tubercle on the pronotum in both sexes, the combination of the following characters can also distinguish this species from all other species: male with very strongly thickened protarsi and very strongly enlarged and elongated inner protibial claw; fourth and sixth intervals with punctures posteriorly; and the shape of the parameres.

Etymology. This species is named for its limited distribution on the continent, which is currently the only species known exclusively from mainland Southeast Asia.

Distribution. Malaysia: Malay Peninsula; Thailand.

Remarks. This species belongs to a group who lacks setation on the parameres (the small white dots on the photographs of the parameres ( Figs. 1D–1E ) are small pieces of dust instead of setae). Other species of this group are: Pseudohomonyx belitungensis Miyake & Yamaya, 1997 , P. borneensis Arrow, 1908 , P. javanus ( Burmeister, 1847) , P. loksadoensis Jákl & Zídek, 2017 and P. minor Jákl & Zídek, 2017 ( Jákl & Zídek 2017).

Pseudohomonyx continentalis Yang & Pathomwattananurak , new species, alongside with P. javanus (more information given in the according section in the catalogue), represents the first records of this genus from mainland Southeast Asia. It is also the only species endemic to the mainland.

It should be noted that the female paratype was assembled from pieces after it died before full melanization. Fortunately, characters can still be clearly visible and compared with the holotype.

Figures

FIGURE 1. Holotype of Pseudohomonyx continentalis Yang & Pathomwattananurak, new species.A, habitus (dorsal view); B, habitus (ventral view); C, head and pronotum; D, parameres (caudal view); E, aedeagus (lateral view).

FIGURE 2. Habitus of paratypes of Pseudohomonyx continentalis Yang & Pathomwattananurak, new species.A, male paratype (dorsal view, ©THNHM/Tatsanai Jeenthong); B–C, female paratype (dorsal and ventral views, ©Thitipong Hongsuwong).