Parena Motschulsky, 1860

Shi, Hongliang & Liang, Hongbin, 2023, Taxonomic revision of the genus Parena Motschulsky, 1860 (Coleoptera, Carabidae, Lebiini, Metallicina), Zootaxa 5286 (1), pp. 1-144 : 83-85

Subgenus Parena Motschulsky, 1860

Type-species: Parena bicolor Motschulsky

The subgenus Parena s. str. includes twenty-three species, defined by the combination of the following characters: pronotum moderately transverse; mandibles strongly widened, semicircular; mentum with a pair of setae, very short in some species, lateral lobes narrow and short, apex slightly extending beyond epilobes, inner margins strongly oblique; accessory setae on antennomeres 1 and 2 absent or very short; elytral first pore on interval 3 close to base, on level of scutellar apex; gonocoxite II of ovipositor nearly rectangular, apex with five to seven ensiform setae. However, all of the above characters are inferred to be plesiomorphic, so subgenus Parena s. str. may be paraphyletic. Moreover, because the species of this subgenus are morphologically similar, treatment of these species as a subgenus is at least convenient for recognition in classification.

Subgenus Parena has the widest distributional range of the three subgenera. Thirteen species have Oriental-Australian distributions, with ten species confined to the Oriental Realm (some of them can reach to the south part of Palaearctic Realm), two to the Australian Realm, and one to both realms. Some of these species are very widely distributed in the Oriental Realm (e.g., P. fasciata ), while others are restricted to certain islands (e.g., P. andrewesi ). Ten species occur in the African Realm, with two of them endemic to Madagascar and the other eight to the Sub-Saharan African mainland.

In the present work, we revise the subgenus Parena with African and Oriental-Australian species separately, for the purpose of providing a taxonomy system easier for species determination. Otherwise, some species groups might be difficult to define. Three Oriental-Australian species groups and three African species groups are recognized, based mainly on the presence or absence of the suborbital setae and male genital characters, including the shape of the median lobe and the copulatory piece of the endophallus.

Diagnostic characters. Dorsal surface reddish brown to piceous; elytra entirely reddish brown, with dark patch or lateral stripes, or entirely metallic green or bluish green. Tempora short, abruptly narrowed behind eyes, length of tempora plus neck-constriction approximately one-third of diameter of eye; antennomeres 1–3 with sparse very short accessory setae in most species; postgenae with or without suborbital setae; mandibles extremely widened, semicircular, retinacular ridge of right mandible reduced to retinacular tooth ( Fig. 2B ); mentum with a pair of setae, very short in some species; lateral lobes short and wide, apically rounded, inner margins strongly oblique, outer margins slightly arcuate, epilobes relatively wide, apices not extending beyond lateral lobes. Pronotum moderately wide, PW/PL = 1.26–1.56, slightly wider than head in most species, PW/HW = 0.92–1.13; lateral explanations wide; lateral margins usually more or less sinuate before posterior angles; posterior angles usually forming rounded angles. Elytral interval 3 with three setigerous pores, first pore close to elytra base, on level of scutellar apex; disc not, weakly, or strongly depressed near middle of interval 5, lateral sides slightly depressed near anterior third. Abdominal sternite VII often with two setae on each side, apex straight in females, usually more or less emarginate in males. Male mesotarsomere 1 usually with biseriate adhesive setae restricted on apical half (but without setae in five species), mesotarsomeres 2 and 3 usually with well-developed adhesive setae. Male genitalia with median lobe slender or stout; endophallus usually with large flared basal expansion of primary sclerite (except for P. bicolor group), squamate sheath largely and heavily scaled. Female ovipositor with gonocoxite II nearly rectangular, apex with five to seven ensiform setae.

Key to Oriental-Australian species in subgenus Parena Motschulsky

1. Postgenae with a pair of long suborbital setae, similar length as supraorbital setae ( Fig. 3E ); primary sclerite of endophallus linear, base not expanded (9. P. bicolor group).............................................................. 2

- Postgenae without suborbital setae ( Fig. 3F ), occasionally with a few short setae, distinctly shorter than supraorbital setae; primary sclerite of endophallus strongly expanded at base..................................................... 4

2. Elytra yellowish brown, disc usually with black patch....................................[26] P. fasciata (Chaudoir)

- Elytra metallic green, with bluish or copperish hue in some specimens........................................... 3

3. Elytra without a median red patch, first interval entirely metallic green; median lobe of aedeagus with right margin very weakly sinuate before apical lamella in dorsal view; the Malay Archipelago........................[24] P. bicolor Motschulsky

- Elytra with a median red patch one to four intervals wide, at least interval 1 red at middle; median lobe of aedeagus with right margin distinctly sinuate before apical lamella in dorsal view; Asian continent...........[25] P. rubripicta Andrewes, 1928

4. Elytra not metallic, with or without black lateral stripes; apical lamella of aedeagus thin, apex bent dorsally in lateral view (10. P. nigrolineata group).................................................................................. 5

- Elytra with metallic green lateral stripes or completely metallic green; apical lamella of aedeagus coniform, apex not bent dorsally in lateral view (11. P. latecincta group)............................................................... 11

5. Elytra yellowish brown to dark reddish brown, with black lateral stripes.......................................... 6

- Elytra completely yellowish brown to piceous or with light patch, without black stripes.............................. 8

6. Tibiae and apex of femora black; elytra lateral margins and posterior half of epipleura black; median lobe of aedeagus stout (AL/AW 4.4–4.6) with very narrow apical lamella (LW much greater than LW); Borneo..............[30] P. picipes sp. n.

- All legs entirely yellow; elytra lateral margins and epipleura yellow; male genitalia not as above...................... 7

7. Elytra with lateral black stripes ended before apex, not extended to interval 1; median lobe of aedeagus stout (AL/AW 3.8); Ryukyu Islands..............................................................[29] P. amamiooshimensis Habu

- Elytra with lateral black stripes extended to interval 1, ended at sutural angle; media lobe of aedeagus slender (AL/AW 5.3– 6.0)................................................................... [27] P. nigrolineata (Chaudoir) [part]

8. Dorsum yellowish to reddish brown; elytral disc with shallow depressions before middle of intervals 3 to 6; elytral striae well incised, intervals slightly convex......................................................................... 9

- Dorsum dark brown to piceous; elytral disc with larger and deeper depressions before middle of intervals 3 to 6; elytral striae very shallowly incised, intervals not convex............................................................... 10

9. Elytra yellowish brown; apical lamella of aedeagus narrower, LL slightly bigger than LW; Oriental Realm...................................................................................... [27] P. nigrolineata (Chaudoir) [part]

- Elytra dark reddish brown; apical lamella of aedeagus wider, LL subequal to LW; Australian Realm.. [28] P. picea (Macleay)

10. Dorsum dark brown, each elytron with three light brown patches; male abdominal sternite VII distinctly emarginate; the Philippines........................................................................... [31] P. andrewesi Jedlička

- Dorsum uniformly dark brown to piceous, elytra without paler patches; male abdominal sternite VII weakly emarginate; New Caledonia, Vanuatu, Samoa...................................................... [32] P. politissima (Chaudoir)

11. Elytra reddish brown, with metallic green lateral stripes, with shallow isodiametric microsculpture, visible at least near apices of inner intervals..................................................................................... 12

- Elytra entirely metallic green, without microsculpture....................................................... 13

12. Elytral disc without metallic hue in brown area; elytral green stripes wider, extended medially at least to interval 6 at middle; male mesotarsomere 1 without adhesive setae ventrally.................................... [33] P. latecincta (Bates)

- Elytral disc with strong purple metallic hue in brown area; elytral green stripes narrower, extended medially only to interval 7 at middle; male mesotarsomere 1 with adhesive setae ventrally near apex.................... [34] P. circumdata Shibata

13. Elytra without reddish copper lustre; abdominal sternum reddish brown to dark brown; elytral striae distinctly incised; elytral disc with shallow but distinct depressions near basal third; China............................[35] P. monticola Shibata

- Elytra with strong reddish copper lustre on humeri and apices; abdominal sternum piceous; elytral striae barely incised; elytral disc with very faint depressions near basal third; Borneo............................... [36] P. pendleburyi Andrewes

Figures

FIGURE 2. Mandibles of Parena spp.: left mandible, dorsum (ld); right mandible, dorsum (rd); left mandible, venter (lv); right mandible, venter (rv). A P. (Crossoglossa) cavipennis (Bates), Shaanxi. B P. (Parena) latecincta (Bates), Zhejiang. C P. (Bothynoptera) dorsigera (Schaum), Guangxi. D P. (Bothynoptera) taiwana Hua, Taiwan. E P. (Bothynoptera) tripunctata (Bates), Beijing. Scale bar = 0.5mm. Abbreviations: rr retinacular ridge of right mandible; vg ventral groove.

FIGURE 3. A–D Labia of Parena spp.: A P. (Crossoglossa) cavipennis (Bates), Beijing. B P. (Parena) latecincta (Bates), Zhejiang. C P. (Bothynoptera) dorsigera (Schaum), Guangxi. D P. (Bothynoptera) tripunctata (Bates), Beijing. E–F Heads of Parena spp. in lateral view: E P. (Bothynoptera) taiwana Hua, Taiwan, suborbital setae present. F P. (Parena) latecincta (Bates), Yunnan, suborbital seta absent. Scale bars = 0.5mm.