Penia takasago Kishii, 1997

Arimoto, Kôichi, 2023, Taxonomic revision of the genus Penia Laporte (Coleoptera, Elateridae, Dendrometrinae) from Taiwan, Zootaxa 5375 (3), pp. 301-335 : 325-328

Penia takasago Kishii, 1997

( Figures 16 , 17 )

Penia takasago Kishii, 1997: 12 (original description; type locality: Taiwan, Nantou County, Sungkang) [partim]; Suzuki, 1999: 121 (catalogue); Cate, 2007: 185 (catalogue); Kundrata et al., 2018: 56 (catalogue).

Type material. Holotype. Female, Taiwan, Nantou County, Sungkang, 21 VII 1969, Y. Maeda leg. [ OMNH; PTK01 ]. Verbatim label data ( Fig. 16A ). “HOLOTYPE”; “SUNGKANG/ FORMOSA / 21. VIII. 1969 / Y. MAEDA ”: “ Penia / takasago/ KISHII, sp. n. / Det. KISHII, ’92”; “ T. KISHII Coll./ OMNH / [15-16]” . Paratype. 1 female, Taiwan, Nantou County, Musha , 7 VIII 1969, T . Kobayashi leg. [ OMNH; PTK02 ] ; 1 female, Taiwan, Nantou County, Sungkang , 6 VIII 1969 (as 6 VII 1969 in original description), Y. Maeda leg. [ OMNH; 6348] .

Female. Diagnosis. This species is characterized by the following features: eyes 0.4 x longer than interocular distance in dorsal view; antennae extending beyond pronotum posterior lateral apices by antennomere VI, surpassing elytral half by antennomere XI; antennomeres III distinctly longer than II; IV 1.3–1.4 x longer than III, 0.8–0.85 x longer than II – III combined; apical maxillary palpomere 2.3–2.5 x longer than wide, shorter than maximum length of eye; pronotum strongly and straightly narrowed anterior to hind angles; posterior edge of pronotum with sublateral incisions; hind angles of pronotum acute, strongly protruding posterolaterad; hypomeron with moderate mesial projection; anterior angle of hypomeron rounded; hind angle of hypomeron claw-like shaped; scutellar shield almost as long as wide; mesosternal process between mesocoxae lower than mesocoxae, not visible in lateral view; posterior edge of mesosternal process 0.1–0.15 x wider than total width of mesosternum; elytron 3.4–3.6 x longer than wide, 2.9–3.0 x longer than pronotum length; abdominal ventrite V curved triangular, rounded apically; spiculum ventrale 3.9–4.6 x longer than length of sternite VIII; ovipositor shorter than length of abdomen.

In Taiwan, five species with broad bodies are known: P. babai , P. inopinata , P. pulla , P. takasago , and P. tsou . Their elytra are less than 4× their widths. They are separated from the elongate species, whose elytra are more than 4× the width. Among broad-bodied species, P. takasago is distinguished from the other congeners by the following characters (the other species in parentheses): eyes 0.4 x longer than interocular distance in dorsal view (eyes 0.2–0.3 x longer than interocular distance in dorsal view); OI: 177–179 (OI: 141–162); pronotum strongly and straightly narrowed anterior to hind angles (pronotum slightly narrowed or slightly widening anterior to hind angles); hind angles of pronotum acute (hind angles of pronotum broad); spiculum ventrale less than 5 x longer than length of sternite VIII (spiculum ventrale more than 5 x longer than length of sternite VIII); ovipositor shorter than length of abdomen (ovipositor longer than length of abdomen).

Penia takasago is remarkable also due to the many sclerotized spines inside the bursa copulatrix and the thick sac extending from around the apex of the bursa copulatrix and splitting in two; however, it is impossible to determine if these features are useful for species identification because the bursa copulatrix in the holotype of P. inopinata was lost and could not be compared to that of P. takasago .

Measurements (n=3; holotype in parentheses). BL: 8.61–8.79 (8.79), BW: 3.43–3.63 (3.58), MAE: 1.33–1.39 (1.39), MBE: 0.75–0.78 (0.78), OI: 177–179 (178), PL: 2.09–2.17 (2.17), PML: 1.63–1.71 (1.71), PW: 2.49–2.66 (2.62), PAW: 1.40–1.51 (1.50), PLI: 81.1–84.1 (83.0), PWI: 175–178 (175), EL: 6.25–6.45 (6.45), EW: 1.74–1.84 (1.82), EI: 341–364 (354), BI: 289–303 (297).

Redescription. Body broad, widest around elytral midlength ( Fig. 16B ); surface generally smooth; interspaces between punctures distinctly larger than fine puncture diameter ( Fig. 16B, C ). Color. Body, antennae and legs reddish brown. Lateral margin of pronotum, and external margins of hypomeron and prosternum paler. Lateral margin of elytra yellow. External edge of mandible, lateral and posterior edges of pronotum and mesosternal process between mesocoxae, posterior edges of hypomera and prosternum, external margin of scutellum and anterior edge of elytra blackish ( Fig. 16B, C ). Body covered with long yellow setae.

Head. Frons flatted medially ( Fig. 16D, E ); frontal carina not complete ( Fig. 16D ); frontal margin rectangular but broadly rounded apically in dorsal view ( Fig. 16E ); frontoclypeal region protruding beyond base of labrum. Eyes relatively normal in convexity, 0.4 x longer than interocular distance in dorsal view ( Fig. 16E ). Antennae extending beyond pronotum posterior lateral apices by antennomere VI, surpassing elytral half by antennomere XI; antennomeres longer than wide; II obconical, shortest, 1.6 x longer than wide; III weakly serrated, 2.2–2.4 x longer than wide, 1.6 x longer than II; IV–XI filiform; IV 3.0–3.1 x longer than wide, 1.3–1.4 x longer than III, 0.8–0.85 x longer than II–III combined ( Fig. 16F ); V 3.5–4.0 x longer than wide, 1.1–1.2 x longer than IV; XI 6.0–6.3 x longer than wide, 1.1–1.15 x longer than X. Mandible bidentate ( Fig. 16D ). Apical maxillary palpomere semicircular ( Fig. 16G ), 2.3–2.5 x longer than wide, shorter than maximum length of eye; anterior edge rounded.

Prothorax. Pronotum hexagonal, 0.8 x longer than wide, roundly widening anteriorly, widest around midlength, and then strongly and straightly narrowed anterior to hind angles ( Fig. 16B ), tallest just behind midlength ( Fig. 16H ), without median longitudinal depression posteriorly; anterior edge weakly concave; anterior angles simple, nearly right angle; punctate lateral ridge extending from anterior angles to hind angles ( Fig. 16B ); hind angles simple, acute, strongly protruding posterolaterad; posterior edge with a moderate sublateral incision near each hind angle, without carinae next to sublateral incisions ( Fig. 16B ). Hypomeron with moderate mesial projection ( Fig. 16I : arrow); anterior angle rounded; mesial edge weakly and broadly rounded; mesial and posterior margins with impunctate ridge ( Fig. 16I ); posterior margin with triangular projection between two large emarginations; hind angle abruptly narrowed to apex, claw-like shaped. Prosternum weakly to strongly incurved ventrally in lateral view ( Fig. 16H ); anterior lobe distinctly protruding beyond prosternal ventral line in lateral view ( Fig. 16H ); anterior edge broadly rounded in ventral view ( Fig. 16C ). Prosternal process broad, 1.8 x longer than procoxal cavity length ( Fig. 16J ), concave between procoxae, strongly curved dorsad from anterior edge of procoxal cavities in lateral view ( Fig. 16H ), without subapical tooth; dorsal lobe roundly expanded anterior to apex in ventral view ( Fig. 16J ); ventral lobe strongly roundly expanded near base and then abruptly narrowed posterad in ventral view ( Fig. 16J ); ventral margin weakly and roundly expanded medially in lateral view ( Fig. 16H ); apex rounded in lateral and ventral views ( Fig. 16H, J ). Pronotosternal sutures not grooved ( Fig. 16I ), nearly straight in ventral view ( Fig. 16C ), slightly opened anteriorly. Scutellar shield tongue-shaped ( Fig. 16K ), 0.95–1.00 x longer than wide, widest anteriorly, weakly constricted anteriorly and narrowed posteriad but parallel-sided in paratype, flat, inclined anterior-downwards, not visible in lateral view ( Fig. 16H ); anterior edge broadly rounded but slightly protruding medially in holotype; posterior edge rounded. Mesosternum: borders of mesosternal cavity slightly rounded and then obtusely curved in lateral view ( Fig. 16H ); mesosternal process between mesocoxae lower than mesocoxae, not visible in lateral view ( Fig. 16H ); posterior edge 0.1–0.15 x wider than total width of mesosternum, weakly to strongly emarginate ( Fig. 16L ). Mesepisternum reaching mesocoxal cavity ( Fig. 16L ). Metasternum sulcate medially and anterior to metacoxal cavities ( Fig. 16L ). Metacoxal plate narrowed toward outer side, becoming like a parallel-sided bar at its outer 1/ 8 in ventral view ( Fig. 16C ). Elytron broadly strongly convex, but with outer margin widely depressed, widest behind midlength, 3.4–3.6 x longer than wide, 2.9–3.0 x longer than pronotum length; apex rounded; elytral striae defined by lines of elongated punctures. Hind wings fully developed. Tibiae with paired spurs; relative tarsomere lengths: IV<III II<V<I; tarsomeres III and IV with lobe ventrally ( Fig. 16M ).

Abdomen. Ventrite V curved triangular, rounded apically ( Fig. 16C ), 0.45–0.5 x longer than wide. Tergite and sternite VIII yellow. Terigite VIII curved triangular, rounded apically, 0.8–0.9 x longer than wide ( Fig. 17A ), 0.7 x longer than wide in paratype (6348); sternite VIII (between base of spiculum ventrale and apex) hexagonal, 0.8 x longer than wide, 0.7 x longer than wide in paratype (6348) ( Fig. 17B ; the subgenital segments of the paratype (6348) had been mounted in balsam on slides and were distorted by the pressure exerted by the coverslip, Fig. 17C, D ); spiculum ventrale 3.9–4.6 x longer than length of sternite VIII ( Fig. 17E ), 3.4 x longer than length of sternite VIII in paratype (6348) ( Fig. 17D ). Ovipositor 0.85–0.9 x longer than length of abdomen; coxites two segmented at ventral side ( Fig. 17F ), with several setae each dorsally, ventrally, and apically; stylus with a seta around apex. Vagina short ( Fig. 17E ); bursa copulatrix elongated spheroid, posteriorly with a short sac ( Fig. 17G : arrow 1); thick sac extending from around apex of bursa copulatrix ( Fig. 17G : arrow 2), splitting in two ( Fig. 17G : arrows 3, 4); many sclerotized spines in various sizes inside bursa copulatrix ( Fig. 17H ).

Male. Unknown.

Discussion. A female paratype of Penia takasago (6349) does not belong to P. takasago but rather to a new species, P. inopinata (see discussion of P. inopinata ).

Platia and Schimmel (2007) reported a male of Penia takasago with a short description as the first record of a male but that was based on misidentification because the specimen differs from P. takasago in the shape of the pronotum and the ratio of the elytron length to pronotum length. Therefore, the male of P. takasago remains unknown. In this study, the male specimen, which is deposited at the Hungarian Natural History Museum, could not be examined.

Distribution. Taiwan: Nantou County ( Fig. 1 ).

Figures

FIGURE 1. Map of Taiwan. A: location of Taiwan; B: the collection sites of the material used in this study.

FIGURE 16. Penia takasago, holotype, female (PTK01). A: labels; B: habitus, dorsal side; C: habitus, ventral side; D: head, anterior view; E: head, dorsal view; F: basal antennomeres of right antenna; G: right maxillary palp, dorsal side; H: head, prothorax and mesothorax, lateral view (black arrow: the direction perpendicular to the base of ventral lobe of prosternal process, white arrow: the direction perpendicular to the mesosternal process between mesocoxae); I: left hypomeron (arrow: hypomeron with moderate mesial projection); J: prosternal process from the direction perpendicular to base of ventral lobe (black arrow of figure 16H); K: scutellar shield; L: mesothorax from the direction perpendicular to mesosternal process between mesocoxae (white arrow of figure 18H); M: right mid tarsus.

FIGURE 17. Penia takasago, females. A, B, E–G: holotype (PTK01); C, D: paratype (6348); H: paratype (PTK02). A: tergite VIII; B: sternite VIII; C: slide; D, E: pregenital segments and genitalia; F: coxites, ventral side; G: vagina and bursa copulatrix (arrow 1: bursa copulatrix posteriorly with a short sac; arrow 2: thick sac extending from around apex of bursa copulatrix; arrows 3, 4: thick sac splitting in two); H: sclerotized spines inside bursa copulatrix.