Eophileurus varipunctatus Yang, Pathomwattananurak & Zhao, 2023

Yang, Qiao-Zhi, Geshev, Georgi, Pathomwattananurak, Wuttipon & Zhao, Ming-Zhi, 2023, Two new species of the genus Eophileurus Arrow, 1908 (Coleoptera: Scarabaeidae Dynastinae) from the Philippines and Vietnam, with first description of E quadratifovealis Yang & Pathomwattananurak, 2022 female, Zootaxa 5249 (2), pp. 290-300 : 291-293

Eophileurus varipunctatus Yang, Pathomwattananurak & Zhao , new species

( Figs. 1A–1F , 3A–3B )

Type material (3♁♁). Holotype: ♁ ( CAU), “ Mt. Halcon , Paitan Barangay , Naujuan Municipality, Oriental Mindoro Prov., Mindoro Is., The Philippines, alt. 1500 m, II.2021, Noel Mohagan leg.” Paratypes: 2♁♁ ( CQZY), same data as the holotype .

Additional material examined (1♀). The Philippines: 1♀ ( CQZY), Mt. Mantalingajan, Brooke’s Point Municipality , Palawan Prov., Palawan Is., The Philippines , alt. 800 m, IV.2019, Noel Mohagan leg.; see remarks below .

Holotype (male). General ( Figs. 1A–1C ): Body black, oblong, flattened, surface moderately shiny; ventral surface with dense, short reddish-yellow setae. Head: Clypeus with dense, small punctures, denser and rugopunctate on sides, with a short and slightly backward, obtuse horn at center, without any ridge from horn to apex; clypeal apex slightly acute, reflexed. Frons slightly depressed, disk with dense, large punctures. Mandible sinuate on outer margin. Pronotum: Surface densely punctate, punctures mostly small, becoming denser on lateral and anterior margins, and rugopunctate on anterior one-fourth of pronotal surface and cluster of dense punctures on each side close to disc, punctures slightly sparser near posterior margin. Anterior region with a small, deep, hexagonal fovea; fovea strongly and densely rugopunctate, margin with 2 weak protuberances on each side posteriorly and close to middle. Lateral margin roundly curved, subparallel at middle; all margins beaded except before fovea, more strongly beaded on sides. Anterior angle protruding, apex slightly rounded, posterior angle obtusely angulate. Scutellum: Surface with sparse punctures near base and on disc. Sides concave near base and convex posteriorly. Elytra: Surface with dense micropunctures, and dense, round or semicircular, large punctures. Interstice 1 with punctures in 2 irregular rows combined to 1 irregular row close to center, interstice 2 with 1 irregular row. Primary costae A and B indistinct, inner punctate row of primary costa B slightly irregular. Punctures in primary costae C, D, E and interstices 3, 4 distinctly larger and deeper than those in more inner primary costae and interstices. Subapical umbone slightly prominent. Margin of elytron weakly and horizontally dilated from base to posterior two-fifth. Pygidium: Slightly convex, with dense, small punctures throughout, very densely rugopunctate near base, punctures slightly sparser on sides and sparser near apex. Metasternum: Punctures dense and large on sides; middle with sparser, slightly smaller punctures; setae on anterior region and each side yellow, short. Abdominal ventrites: Surfaces with sparse, small punctures throughout, punctures becoming slightly denser and larger on each side, some bearing setae; ventrite 6 rugopunctate on anterior region. Legs: Protibia tridentate, protarsus strongly thickened, inner protibial claw strongly enlarged, elongated. Inner metatibial spur long, slightly curved outward, outer metatibial spur shorter, slightly more strongly curved outward. Parameres ( Figs. 3A–3B ): In frontal view ( Fig. 3A ), slender and symmetric; lateral margin strongly convex at middle, and strongly concave on basal onefourth, with a pair of large, acute, slightly backward processes subapically; inner margin with dense and small teeth from posterior one-third to near apex, more than one layer close to apex; apex rounded; in lateral view ( Fig. 3B ) apex curved downward, with a slightly backwards process near apex, with a backwardly curved ridge close to center, upper margin sinuate, rather strongly curved downward near apical one-third.

Paratypes (male). Characters mainly stable, except protuberances at the margin of fovea absent.

Female. Similar to male, except clypeus and frons much more densely rugopunctate throughout; clypeal horn much shorter, reduced to a tubercle; fovea absent, with an extremely shallow and small depression on anterior region of pronotum; pronotum more weakly rugopunctate anteriorly; anterior margin of pronotum entirely beaded; scutellum without inward curves at side near base; protarsus not thickened, inner protarsal claw not enlarged and elongated ( Figs. 1D–1F ).

Measurements. Length: male 25.2–25.8 mm (holotype 25.7 mm), female 26.7 mm; width: male 12.7–13.4 mm (holotype 13.4 mm), female 13.7 mm.

Diagnosis. The new species is most closely related to Eophileurus iwasei Muramoto, 1995 ( Figs. 2A–2F, 2C– 2D ) due to the parameres of similar shape, with a series of small teeth in the inner margins, and the similar external characters. We have only examined an underdeveloped male of the latter species. Although the original description of E. iwasei was based on a more developed male (body length 22.8 mm; Muramoto 1995), we remain unsure whether it is a well-developed individual. And the three examined male specimens of the new species are basically of the same size, which makes development unclear. However, the following characters allow an easy separation of the two species (those of E. iwasei are in parenthesis):

Body distinctly wider (more slender in E. iwasei ); scutellum with an inward curvature close to base at each side in male (absent in E. iwasei ); elytral punctures in primary costae C, D, E and interstices 3, 4 distinctly larger and deeper than those in inner primary costae and interstices (all elytral punctures regularly and universally sized in E. iwasei ); elytral punctures much larger than micropunctures (differences of puncture sizes less distinct in E. iwasei ); pygidium with sparser and slightly smaller punctures; mesosternum with denser punctures at each side, punctures slightly smaller close to center; apex of paramere semicircular, enlarged, with a sharp, short, outward and backward process at external side (apex of paramere flat, weakly enlarged, with a pair of sharp, rather short processes at external side in E. iwasei ); female pronotum only with a very small and shallow fovea anteriorly (female pronotum with a rather big and deep sub-triangular fovea at anterior region and a shallow furrow behind it extending to base).

The parameres of the new species also resembles Eophileurus niii Yamaya & Muramoto, 2008 ( Yamaya & Muramoto, 2008b) since both are slender and have similar apices with small, backward process at each side. E. niii is, however, not considered closely related to the new species due to the base of its parameres slightly overlapping and the different size of the teeth on the inner margin as well as the different external characters.

Etymology. The specific epithet is a combination of the Latin prefix “ vari ” and the adjective “ punctatus ”, referring to the peculiar arrangement of elytral punctures, which distinctly varies in sizes on different striae.

Distribution. The Philippines (Mindoro Island, Palawan Island).

Remarks. All the specimens of the new species were purchased from the local collector N. Mohagan from Mindoro, the Philippines. Although geographically close, many groups widespread through the Philippine Modile Belt (PMB, including Mindoro Island) are absent from Palawan Island ( Heads 2013). It is rare to see shared taxa of pleurostict scarabs between the two regions, e.g., Carlschoenherria palawana (Moser, 1915) , Philgertia lii ( Keith, 2006) and Parastasia bimaculata bimaculata (Guérin-Méneville, 1843) ( Itoh 1993; Keith 2006; Kuijten 1992). Since the distribution of Eophileurus iwasei covers a large majority of PMB ( Yamaya & Muramoto 2008a), it is surprising to find a similar species in both PMB and Palawan regions. The female from Palawan is tentatively assigned to the new species due to its external affinity to the male specimens, especially from the characteristically enlarged elytral punctures in primary costae C, D, E and interstices 3, 4. Given that females between closely related Eophileurus species are often indistinguishable from each other externally and neither associated male from Palawan nor female from Mindoro are available, we therefore do not treat the female as a paratype. We also cannot exclude the possibility that these specimens were partly mislabeled by the dealer.

A similar case of such distribution pattern occurs in Java Island, i.e., E. javanus Prell, 1913 and E. niii Yamaya & Muramoto, 2008 ( Yamaya & Muramoto 2008b). However, they may not form a monophyletic clade since there are several species morphologically more similar to E. javanus in nearby island groups. Another hypothesis is that E. varipunctatus and E. iwasei are not vicariant siblings, their ancestors dispersed into the Philippines through different paths, e.g., by crossing Palawan or Sulu.

Apart from the two Philippine species mentioned above, there is also a doubtful record of E. chinensis ( Faldermann, 1835) from “Agusan River, Mindanao Is.” ( Schultze 1916; Muramoto 1995). This record might be based on a misidentified specimen of E. iwasei . However, the exact identity of the specimen might not be confirmed due to the destruction of Bureau of Science of Manilla during World War II, which housed the specimen cited by Schultze (1916) (but some material originally deposited in Bureau of Science which belongs to Baker’s collection was moved to the United States before its destruction). Although E. chinensis can be found on Taiwan Island and small islands of Okinawa, there are no records in the Taiwan-Luzon Volcanic Arc, a path for the interchange between Taiwan Island and the Philippines. Thus, the distribution of E. chinensis in the Philippines should be omitted.

Figures

FIGURE 1. Habitus of Eophileurus varipunctatus Yang, Pathomwattananurak & Zhao, new species. A–C, holotype; D–F, female; A, D, dorsal view; B, E, ventral view; C, F, oblique view.

FIGURE 2. Habitus of Eophileurus iwasei Muramoto, 1995. A–C, male (Mindanao Island); D–F, female (Leyte Island); A, D, dorsal view; B, E, ventral view; C, F, oblique view.

FIGURE 3. Male genitalia of Eophileurus species. A–B, E. varipunctatus Yang, Pathomwattananurak & Zhao, new species, holotype; C–D, E. iwasei Muramoto, 1995; A, C, frontal view of parameres; B, D, lateral view of aedeagus.