Eophileurus quadratifovealis 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 : 472-474

Eophileurus quadratifovealis Yang & Pathomwattananurak , new species

( Figs. 1b , 99–102 , 113–114 , 175–180 )

Type material. (3♂♂). Holotype: (♂, THNHM), “ Pluang Subdist. , Khao Khitchakut Dist., Chanthaburi Prov., Thailand, 31.III.2019, T. Unnahachote & T. Hongsuwong leg.” Paratype: 1♂ ( CWT), “Mu Si Subdist., Pak Chong Dist., Nakhon Ratchasima Prov., Thailand, 12.VIII.2019, W. Pathomwattananurak leg.”; 1♂ ( BMNH), Paralectotype of Eophileurus siamensis Arrow, 1914 , labeled: “SYN-TYPE // Chatabon S. S. Flower. 99-243. // NHMUK 014380701”, two additional red labels will be provided labeling: “ Paralectotype Eophileurus siamensis Arrow, 1914 des. Yang & Pathomwattananurak 2022” and “ Paratype Eophileurus quadratifovealis Yang & Pathomwattananurak, 2022 ”, examined through photographs provided by Keita Matsumoto.

Holotype (male). General ( Figs. 99–100 , 113 ): Body black with slight reddish color, rather oblong, flattened, surface shiny; ventral surface clads with extremely sparse, short reddish-yellow setae. Head: Clypeus sparsely punctate, punctures minute, with a short, backward horn at center and a ridge from horn to apex; clypeal apex slightly rounded. Frons depressed, disk almost impunctate, with punctures at each side anteriorly only. Mandible slightly sinuate at outer margin. Pronotum: Surface with dense and large punctures, becoming denser and larger close to all margins. Anterior region with a large, slightly deep, square-shape fovea; punctures in fovea spare and large, transverse, coalescent at anterior part, slightly denser and smaller at posterior region; sides of fovea almost parallel, with a very weak protuberance at each side at posterior part. Sides parallel at middle; all margins beaded except before fovea, more strongly at sides. Anterior angle acute, apex slightly rounded, posterior angle obtusely angulate. Scutellum: Surface with dense punctures except region close to apex. Elytra: Surface with dense micropunctures, and dense, U-shape, large punctures. Interstice 1 with punctures in four irregular rows combined at middle to two irregular rows, interstice 2 with chaotic punctures, rows unrecognizable. Primary costa A highly distinct, primary costa B not distinct. Subapical umbones moderately prominent. Margins of elytra moderately horizontally dilated from base to middle. Pygidium: convex, with fine punctures throughout, punctures denser and smaller close to all margins, and slightly sparser near apex. Metasternum: Surface mainly black, with reddish color at central region; punctures dense and large near all sides; central portion with sparse and small punctures only; setae yellow, very sparse and short, only at posterior region close to each side. Abdominal ventrites: Surfaces with micropunctures throughout and larger punctures at each side; last ventrite with rugose, large punctures at anterior region, micropunctures denser and larger than on other ventrites; ventrites 5 and 6 with very shallow, round depressions at center. Legs: Protibia tridentate, protarsi strongly thickened, inner protibial claw strongly enlarged and elongated. Inner metatibial spur long, slightly curved outward, outer metatibial spur shorter, more strongly curved outward. Parameres ( Figs. 175–176 ): In frontal view ( Fig. 175 ), base overlapped, extending upward; outer sides sinuate, prominent outward at posterior two-fifth, anterior one-seventh and near apex; inner sides also sinuate, prominent inward posterior to opening; in lateral view ( Fig. 176 ), base projected upward and slightly backward; apex bent strongly backward, with a tiny, backward, triangular process near apex of each paramere; in ventral view, ventral base with a pair of short, outward, flat, semicircular processes.

Paratypes (male). Underdeveloped, but characters mainly stable, except clypeal horn much shorter, clypeus and frons slightly denser punctate; Fovea much smaller and shallower, rather rounded, with denser punctures; micropunctures on elytra denser ( Figs. 101–102 , 114 ); Base of parameres wider and less upwardly extended in front view, region from middle to apex of parameres narrower, ventral basal processes visible in front view ( Fig. 177 ), base of parameres more prominent and processes close to apex almost absent in lateral view ( Fig. 178 ).

Female. Unknown.

Measurements. Body length: male 21.8–25.0 mm (holotype 25.0 mm), female unknown; body width: male 10.5–12.1 mm (holotype 12.1 mm), female unknown.

Diagnosis. This new species is most similar to E. confinis Prell, 1913 , but differs by: middle of pronotum parallel ( Figs. 99, 101 ) whereas usually not parallel in E. confinis ; fovea square-shape for normally developed individual; interval 1 wider; parameres with different shape, especially without a pair of processes at the middle of the sides ( Figs. 175–180 ).

Etymology. This new species is named for the unique square-shaped fovea of the holotype, which is not present in other Indochina Eophileurus . The species epithet is a combination of the Latin adjective “ quadrate ” and noun “ fovea ”, to be used as noun in apposition.

Distribution. Thailand.

Remarks. This species is most closely related to E. confinis Prell, 1913 , whose distribution surrounds its distribution in a large scale. Currently, whether they are sympatric is unknown. With only three specimens examined from adjacent but separated mountain ranges, their parameres show considerable variations. This is likely to be in similar situation as E. confinis where individuals tend to have distinct variation on the parameres both individually and geographically. Since the overall structures of the new species’ parameres can be traced, the three individuals are treated as the same species. Additionally, due to the high similarity between the males of E. quadratifovealis , new species and E. confinis , the author speculate that the females of this species might also be highly similar to each other and have elytral margin more strongly dilated than the males, as commonly seen in females of E. confinis .

Figures

FIGURE 1. Elytra of Eophileurus Arrow, 1908 species. a, E. quadrigeminatus Arrow, 1914; b, E. quadratifovealis Yang & Pathomwattananurak, new species; c, E. felschei Prell, 1913. Primary costae marked in yellow and labeled in capital letters, interstices labeled in numbers without additional coloring.

FIGURES 99–102. Habitus of Eophileurus quadratifovealis Yang & Pathomwattananurak, new species. 99–100, holotype; 101–102, paratype; 99, 101 dorsal view; 100, 102, 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.