Parastasia spinosa Hongsuwong, Sanguansub & Jaitrong, 2022

Hongsuwong, Thitipong, Sanguansub, Sunisa & Jaitrong, Weeyawat, 2022, A new species and a new synonym in the scarab genus Parastasia Westwood, 1841 (Coleoptera: Scarabaeidae: Rutelinae), with a key to species from Thailand, Zootaxa 5205 (6), pp. 547-562 : 548-550

Parastasia spinosa Hongsuwong, Sanguansub & Jaitrong , new species

( Figs. 1–16 )

Type material. Holotype, male (THNHM-I-09998, THNHM), THAILAND: Chanthaburi province, Soi Dao district, Pong Nam Ron, Khlong Thap Mark , 12°54′313″N, 102°13′089″E, 18.V.2008, T. Jeenthong leg., previous number THNHM-I-2008-04018.

Description of holotype. General: Head, metasternite, abdominal ventrites, and legs dark brown; pronotum, elytra, propygidium, pygidium, and ventral prothoracic surface glossy reddish brown; antennae, scutellum, and tarsal claws dark reddish brown. Head: Clypeus subrectangular, clearly shorter than width, lateral margin almost straight with anterior corner rounded; anterior margin of clypeus moderately convex and curved upward bearing 2 sharp denticles medially; posterior clypeal margin convex, obsolete medially, and present as ridge laterally; median portion of surface shagreened, anterior and lateral portions almost smooth and shiny. Ocular canthus small, simply pointed backward with blunt apex; apex with a few of short erect setae (0.10 mm). Eyes entirely round and distinctly convex with ratio of HW and IOD of approximately 0.64. Surface of frons wrinkled, glabrous. In dorsal view, mandibles subrectangular, clearly longer than width, the external margin sinuate, apically truncate, internal margin edentate, and concave. Galea of maxilla with 3 teeth, apical tooth bifurcated. Labrum subrectangular with anterior margin trilobed. Mentum slightly longer than width, its lateral margin concave in apical one-third and roundly convex two-thirds from anterior margin; anterior margin of mentum curved down and concave medially. Antennae 10- segmented, combination of segments 1–7 almost as long as antennal clubs. Pronotum: Clearly shorter than width, widest between posterolateral corners, ratio of PL and PW approximately 0.69; in dorsal view, lateral margin convex in posterior half and almost straight or feebly concave in apical half, anterior margin almost straight, and posterior margin weakly convex; anterolateral corner of pronotum bluntly angulate, and posterolateral corner roundly protruding; anterior and lateral margins marginate with distinct rim. Surface punctate, interspaces of punctures smooth and shiny; punctures on disc sparser and smaller than on lateral portion; mediolateral portions of pronotum with a shallow impression. Scutellum: Subtriangular, clearly shorter than width (0.67 times as long as width), lateral margins roundly convex. Surface with sparse micropunctures. Elytra: In dorsal view, longer than width, widest medially, the external margins convex; area behind one-fourth of external margins impressed; external margins marginated with indistinct rim, obsolete before sutural apices; posterior margin convex, sutural apices blunt. Elytral surface with 11 rows of parallel punctures; areas between the punctate rows almost smooth. Abdominal tergites: Propygidium clearly shorter than width, its anterior and posterior margins convex; anterior half of surface punctate, while posterior half superficially shagreened. Pygidium width (0.46 as long as width); anterior margin weakly concave medially, anterolateral corner round; lateral margin marginated with thick rim and the rim obsolete around apex; surface along lateral and posterior margins of pygidium superficially shagreened, remaining area relatively smooth. Ventral thoracic surface: Ventral prothoracic surface flat; prosternal process distinctly produced as distinct ridge. Metasternite subrectangular shorter than width with a longitudinal groove medially; metasternal process stoutly produced anteriorly, apex reaching level of anterior margin of mesocoxae; lateral portions of metasternite rugopunctate, covered with dense and long decumbent setae (0.40–0.60 mm), median portion somewhat smooth and shiny with sparse micropunctures. Abdominal ventrites: Ventrites 2–5 very short, but not abbreviated, each segment subequal in length; ventrite 6 abbreviately small with posterior margin feebly concave medially. Median portion of ventrites 2–5 sparsely and shallowly punctate, lateral portions reticulate with a row of decumbent setae (0.21–0.29 mm), shorter and more indistinct near median portion; segment 6 wrinkled, posterior margin of abdominal ventrite 6 with a row of setae (0.20–0.26 mm). Legs: Pro- and mesofemora subcylindrical, metafemur flat. External margin of protibia tridentate apically; internal margin of protibia straight and deeply concave basally; apex of external margin of mesotibia with a sharp denticle; apex of external margin of metatibia bluntly bidentate. Each tarsal segment subcylindrical and not abbreviated; tarsal segment 5 shorter than segments 1–4 combined; ventral margin of tarsal segment 4 with a long spinose process produced downward apically; both protarsal claws simply sickle-shaped with internal claw slightly larger than external claw; internal claw of meso- and metatarsi simply sickle-shaped, external claw bifurcate with upper tooth clearly smaller than lower tooth. Male genitalia: parameres symmetric and parallel, widest basally; in dorsal view, their internal margins touching each other; external margin of parameres sinuate, anterior two-fifths concave, the next fifth convex; posterior margins of parameres roundly convex; in lateral view, parameres with almost straight dorsal and ventral margins but curved down around apex; parameres in ventral view relatively narrow and subtriangular, internal margins weakly convex basally and roundly concave medially. In lateral view, dorsal margin of phallobase bilobed. Median sac of endophallus with 3 types of spines: 1) subtriangular, thick and short spines located on anterior part of the sac; 2) normal spines with sharp apex located on posterior part; 3) five dark and large spines on ventral margin of posterior part of the sac.

Measurements: TL 12.55 mm; BH 5.31 mm; EL 6.88 mm; EW 7.49 mm; PL 4.34 mm; PW 6.25 mm; HW 2.83 mm; IOD 1.81 mm; ED 1.09 mm.

Differential diagnosis. According to reddish or reddish-yellow color and bifurcate external claw of meso- and metatarsi, the resembling of Parastasia discolor group (sensu Ohaus 1900) are looked at the first sight.Among them, Parastasia spinosa , new species is most similar to Parastasia discolor Westwood, 1841 by comparing images of its type series ( Figs. 17–28 ). They share similar characteristics in having the mandibles subrectangular with sinuate external margin, truncate apically, and with concave internal margin; the straight dorsal margin of the parameres in lateral view; and the straight internal margin of the parameres which touch each other in dorsal view. However, P. spinosa , new species can be distinguished from P. discolor by the following characteristics (characters of P. discolor in parentheses unless otherwise stated): 1) anterior margin of labrum almost straight (anterior margin of labrum clearly convex); 2) prebasal and basal maxillary teeth width and with blunt apex (prebasal and basal maxillary teeth narrow and sharp apex); 3) posterior margin of pronotum weakly convex (posterior margin of pronotum distinctly convex); 4) The first row of punctures on elytra (close to internal margin) sinuate (first row of punctures on elytra almost straight); 5) external claws of metatarsi bifurcate, the upper tooth clearly shorter than lower tooth (upper tooth longer than lower tooth); 6) in dorsal view, parameres widest at base (widest at middle); 7) in lateral view, dorsal and ventral margins of parameres almost straight without distinct concavity, apex roundly angulate (dorsal margin convex, ventral margin concave, sharp apex); 8) endophallus with numerous different sizes of spines (endophallus with only small spines).

Etymology. The specific epithet “ spinosa ” is a Latin word meaning covered with spines. This refers to the median sac of the endophallus which is covered with three different types of spines.

Distribution. The new species is known only from the type locality in Chanthaburi province, eastern Thailand.

Figures

FIGURES 1–5. Parastasia spinosa Hongsuwong, Sanguansub & Jaitrong, new species (holotype, male, THNHM-I-09998). 1, habitus in dorsal view; 2, habitus in ventral view; 3, habitus in lateral view; 4, habitus in caudal view; 5, inner side of right protarsus.

FIGURES 6–16. Mouthparts and male genitalia of Parastasia spinosa Hongsuwong, Sanguansub & Jaitrong, new species (holotype, male, THNHM-I-09998). 6, 7, labrum; 8, 9, left mandible; 10, 11 maxillae; 12, mentum; 13, 14, 15, male parameres; 16, endophallus; 6, 8, 10, 13, dorsal view; 7, 9, 11, 12, 14, ventral view.

FIGURES 17–22. Parastasia discolor Westwood, 1841. 17–19, Parastasia discolor discolor Westwood, 1841, Philippines, photo by Keita Matsumoto, (lectotype, NHMUK015009538); 20–22, Parastasia mirabilis Arrow, 1899 (= Parastasia discolor scutellaris (Erichson, 1845)), Malaysia, photo by Christophe Rivier (lectotype, MNHN-EC1425); 17, 20, habitus in dorsal view; 18, 21, habitus in ventral view; 19, 22, habitus in lateral view.

FIGURES 23–28. Male aedeagus and type labels of Parastasia discolor Westwood, 1841. 23–25, Parastasia discolor discolor Westwood, 1841, Philippines, photo by Keita Matsumoto, (lectotype, NHMUK015009538); 26–28, Parastasia mirabilisArrow, 1899 (= Parastasia discolor scutellaris (Erichson, 1845)), Malaysia, photo by Christophe Rivier (lectotype, MNHN-EC1425); 23, 26, parameres in dorsal view; 24, 27, aedeagus in lateral view; 25, 28, type labels.