Eophileurus minor Yang & Pathomwattananurak, 2022

Yang, Qiao-Zhi & Pathomwattananurak, Wuttipon, 2022, Four new species of the genus Eophileurus Arrow, 1908 (Coleoptera: Scarabaeidae Dynastinae) from Thailand and Vietnam, with notes on some Indochinese species, Zootaxa 5165 (4), pp. 451-485 : 468-469

Eophileurus minor Yang & Pathomwattananurak , new species

( Figs. 87–92 , 109–110 , 169–172 , 185–192 )

Type material. (14♂♂, 19♀♀). Holotype: (♂, THNHM), labeled: “ Bua Yai Dist. , Nakhon Ratchasima Prov., Thailand, 5.IX.2020, S. Kongsukthana leg.” Paratypes: 1♀ ( THNHM), same label as the holotype ; 1♀ ( CYQZ), same label as the holotype ; 1♂, 1♀ ( CYQZ), “ Mueang Nakhon Ratchasima Dist., Nakhon Ratchasima Prov., Thailand, 26.IX.2020, S. Watcharachod leg.” ; 1♂ ( CYQZ), “ Mueang Nakhon Ratchasima Dist., Nakhon Ratchasima Prov., Thailand, 2020, S. Watcharachod leg.” ; 1♀ ( CWP), “ 15°17’03"N, 104°51'48"E, Ubon Ratchathani Prov., Thailand, 20.XI.2020, T. Unnahachote leg.” ; 1♂, 1♀ ( CWP), “ Ban Mai Subdist. , Mueang Nakhon Ratchasima Dist., Nakhon Ratchasima Prov., Thailand, 2020, K. Pongsirisopaporn leg.” ; 1♂ ( CWP), “ Phanat Nikhom Dist. , Chonburi Prov., Thailand, Pichaphop Junaime leg., adult emerged in VII.2021 ” ; 1♀ ( CWP), “ Nong Nak Subdist. , Nong Khae Dist., Saraburi Prov., Thailand, 22.VII.2021, Bannatad Benja leg.” ; 3♂♂, 6♀♀ ( CWT), “ F1 generation of female from Nong Nak Subdist. , Nong Khae Dist., Saraburi Prov., Thailand, 22.VII.2021, Bannatad Benja leg., adult emerged in XI.2021 ” ; 2♂♂, 4♀♀ ( CYQZ), “ F1 generation of female from Nong Nak Subdist. , Nong Khae Dist., Saraburi Prov., Thailand, 22.VII.2021, Bannatad Benja leg., adult emerged in XI.2021 ” ; 2♂♂, 3♀♀ ( CWP), “ Khwan Mueang , Selaphum Dist., Roi Et Prov., Thailand, 18.IX.2021. Nattapat Kamhom leg.” ; 1♂ ( CYQZ), “ Street Thanon Chaiyaphruek , Na Kluea Subdist., Bang Lamung Dist., Chon Buri Prov., Thailand, alt. 5 m, 2.II.2020, BoNing Li leg.” ; 1♂ ( CYQZ), “ Dong Tien Commune , Ham Thuan Bac dist., Binh Thuan Prov., Vietnam, V.2020, Van Dang leg.”

Holotype (male). General ( Figs. 87–88 , 109 ): Body black with very slight reddish color, rather oblong, flattened, surface shiny; ventral surface clads with very dense, long reddish yellow setae. Head: Clypeus densely punctate with rugopunctures, with a very short, slightly backward, conical horn at middle, an indistinct ridge from horn to apex and a more distinct ridge behind the horn; clypeal apex rounded. Frons slightly depressed, disk with dense, small punctures, becoming denser and larger near sides. Mandible slightly sinuate at outer margin. Pronotum: Surface with dense, small punctures, becoming denser and larger near all margins. Anterior region with a small, very shallow, round fovea; punctures in fovea dense and large. All margins moderately beaded except before fovea, more strongly beaded at sides. Anterior angle acute, apex slightly rounded, posterior angle obtusely angulate. Scutellum: Surface almost impunctate, with only a few small punctures at center. Elytra: Surface with dense micropunctures, each with scale-liked seta, and dense and large, sub-U-shape or round punctures. Interstice 1 with punctures in two to three irregular rows combined at middle to one irregular row, interstice 2 with punctures in one irregular row. Primary costa A and primary costa B indistinct. Subapical umbones slightly prominent. Margins of elytra parallel, strongly and horizontally dilated from base to posterior two-fifth. Pygidium: convex, with dense, small punctures throughout, punctures denser and smaller near apical margin. Metasternum: Surface mainly dark reddish, with darker color at posterior region; region near sides with dense and large punctures; central portion with only sparse and small punctures; setae reddish yellow, long, near all margins except posterior margin. Abdominal ventrites: Surfaces with sparse micropunctures throughout and larger punctures at each side except on ventrite 6; ventrite 6 with large punctures throughout and a distinct, horizontally oval depression at center. Legs: Protibia tridentate, protarsi strongly thickened, inner protibial claw distinctly enlarged and elongated. Inner metatibial spur very long, strongly curved outward near apex; outer metatibial spur shorter, slightly curved. Parameres ( Figs. 169–170 ): In frontal view ( Fig. 169 ), inner margins overlapping from middle to near apex; outer sides strongly prominent outward at basal and middle regions; with a pair of wide processes close to middle extending almost to apex, apex of each process extending upward and curving inward, processes at asymmetric positions; apex extending outward; in lateral view ( Fig. 170 ), processes near middle trapezoid; apex bent backward.

Paratypes (male). Characters mainly stable, for paratypes from Thailand ( Fig. 89 ): in general, compared to the holotype, elytral margin very rarely much less dilated; parameres sometimes more slender, overlapping area very rarely much smaller than the holotype, processes sometimes thinner, rarely wider, very rarely at symmetric positions; for individuals more well-developed than the holotype, clypeus and frons more sparsely punctate; clypeal horn longer; all margins of pronotum beaded; fovea slightly larger and deeper, with a very weak protuberance at each side at posterior part, punctures within fovea much sparser; for individuals more underdeveloped than the holotype, clypeus and frons more densely rugopunctate; clypeal horn shorter; fovea absent ( Figs. 185–187, 190– 192 ); for the paratype from Vietnam ( Fig. 92 ): slightly more well-developed than the holotype, characters generally identical to well-developed males from Thailand, except elytral margin slightly less dilated; processes of parameres much thinner, not extending to apex, at symmetric positions ( Figs. 171–172 ).

Paratypes (female). Similar to male, with clypeus and frons much more densely rugopunctate throughout; clypeal horn much shorter; fovea absent; all margins of pronotum beaded; elytral margin slightly more strongly enlarged and extended further posteriorly; depression absent on last ventrite; protarsi not thickened, inner claw not enlarged and elongated; Inner metatibial relatively shorter, spur less strongly curved outward, sometimes straight ( Figs. 90–91 , 110 ).

Measurements. Body length: male 17.3–22.5 mm (holotype 19.3 mm), female 18.1–22.0 mm; body width: male 8.8–11.3 mm (holotype 9.6 mm), female 9.2–11.2 mm.

Diagnosis. This species can be distinguished from other Eophileurus by its overall small size, strongly horizontally enlarged elytral margin which extends beyond the level of midpoint of elytron ( Figs. 87, 89–90, 92 ), significantly long and curved inner metatibial spur ( Figs. 87–92 ) and the unique shape of the parameres ( Figs. 169–172 , 185–192 ).

Etymology. The name refers to its uniquely small size compared to similarly developed individuals of all other Indochinese Eophileurus .

Distribution. Thailand, Vietnam.

Variations. The phenomenon of unstable morphology of the parameres is also seen in this species. Indicated in Figs. 185–187 , are parameres of males raised from eggs laid by the same wild female, in which variations such as the lateral processes are slightly differently shaped, and a pair of very small teeth can be seen on the lateral margin in the first two individuals but absent in the third. Distinct geographical variations can also be seen in Figs. 185–192 , with slight variations on certain parts which are mentioned above in the paratypes (male) section.

Remarks. This species is likely closely related to some Indian species due to the following two aspects. Firstly, the morphology of its parameres ( Figs. 169–172 , 185–192 ) has an overlapping region close to the center in front view which is shared in many Indian species such as E. felschei Prell, 1913 , ( Figs. 45–47 , 51–52 ). Secondly, the small size of this species is unique amongst Indochinese species, whereas it is more commonly seen in Indian species. All specimens of this species examined are from low altitude regions. Additionally, the gap in its known distribution between eastern Thailand and southern Vietnam suggests probable occurrence in regions with similar environment in Cambodia and Laos.

Figures

FIGURES 87–92. Habitus of Eophileurus minorYang & Pathomwattananurak, new species. 87–88, holotype; 89, male paratype (Mueang Nakhon Ratchasima); 90–91, female paratype (Bua Yai); 92, male paratype (Dong Tien, image ©Ming-Zhi Zhao); 87, 89, 90, 92 dorsal view; 88, 91, ventral view.

FIGURES109–116.HabitusofEophileurusArrow,1908species(obliqueview).109–110,E.minorYang&Pathomwattananurak, new species, 109, holotype, 110, female paratype; 111–112, E. prelli Yang & Pathomwattananurak, new species, 111, male paratype; 112, female paratype; 113–114, E. quadratifovealis Yang & Pathomwattananurak, new species, 113, holotype, 114, paratype (Mu Si), 115–116, E. sidereus Yang & Pathomwattananurak, new species, 115, holotype, 116, female paratype.

FIGURES 165–184. Parameres of Eophileurus Arrow, 1908 species. 165–166, E. confinis Prell, 1913 (Bao Loc); 167–168, E. heyrovskyi Kral & Strnad, 1992 (Longli); 169–172, E. minor Yang & Pathomwattananurak, new species, 169–170, holotype, 171–172, paratype (Dong Tien, images ©Ming-Zhi Zhao); 173–174, E. prelli Yang & Pathomwattananurak, new species, holotype; 174–180, E. quadratifovealis Yang & Pathomwattananurak, new species, 175–176, holotype, 177–178, paratype (Mu Si), 179–180, paratype (Chatabon, images by Keita Matsumoto ©Natural History Museum, London); 181–184, E. sidereus Yang & Pathomwattananurak, new species, 181–182, holotype, 183–184, paratype; odd number ones, front view; even number ones, lateral view; scale bar = 2 mm.

FIGURES 185–196. Parameres of Eophileurus Arrow, 1908. 185–192, E. minor Yang & Pathomwattananurak, new species, 185–187 from male offspring of the same wild female from Saraburi, 188 from Dong Tien; 189–190 from Bua Yai; 191 from Mueang Nakhon Ratchasima; 192 from Phanat Nikhom; 193–196, E. sidereus Yang & Pathomwattananurak, new species, male offspring of the same wild female; not to scale.

FIGURES 38–48. Type specimens of Eophileurus felschei Prell, 1913. 38–31, lectotype, female, 38, habitus, dorsal; 39, habitus, lateral; 40, habitus, ventral; 41, labels; 42–48, lectoparatype, male (images ©MTD/Olaf Jäger), 42, habitus, dorsal; 43, habitus, lateral; 44, habitus, ventral, 45–46, parameres, apical; 47, parameres, lateral; 48, labels.

FIGURES 49–53. Holotype of Eophileurus grossepunctatus Dupuis, 2014 (images ©MNHN/A. Mantilleri). 49, habitus, dorsal; 50, habitus, lateral; 51, parameres, apical; 52, parameres, lateral; 53, labels.