Panesthia ( Serville, 1831: 38 )

Panesthia ( Serville, 1831: 38) View in CoL

Proterodia ( Costa, 1866: 5; synonymised by Princis, 1965: 309)

Dicellonotus ( Butler, 1882: 387; synonymised by Roth, 1977: 12)

Type species: Panesthia angustipennis ( Illiger, 1801)

Diagnosis (primarily following Roth, 1977, 1979b, as in Wang et al. 2014): Colour reddish brown, fulvous or black. Size ranging from 15 mm to over 50 mm. Body strongly sclerotised and punctate, with punctation density increasing posteriorly. Head typically punctulate, vertex with or without foveola; eyes large, ocelli may be fully developed, reduced or absent. Antennae moniliform. Pronotum convex to transverse, with or without anteromedial reflexed tubercle, anterior margin variably excised or entire. Anterior half variably depressed, surface punctate to granular with pair of oblique transverse groves. Anterior cornua and posterior disc tubercles may be present, typically more pronounced in males. Tegmina and wings unicoloured or not; fully developed, reduced or absent, or tegmina reduced and wings absent. Fully developed or partially reduced wings and tegmina frequently mutilated terminally, leaving basal portions as remains. Tibiae strongly spined. Tarsi with five segments, pulvilli present on segments 1–4, hind metatarsus shorter than remaining segments combined; claws symmetrical and without arolia.

Abdominal terga usually hairless, hind margins entire and without teeth or tubercles. Anterolateral corners of tergites 3–7 with or without holes, holes usually without setae, size of the holes increasing posteriorly. Lateral margins of tergite 7 straight, weakly uneven, or concave on posterior half; laterocaudal angles often produced and directed caudad. Caudal angles of supra-anal plate obtuse, variably rounded; hind margin dentate, crenulate or entire. Posterior margin of sternite 7 concave, truncate or subtruncate in males, exposing subgenital plate; convex, entire in females, without subgenital plate. Cerci short, unsegmented, bulbous, ventrally setose, dorsoapically setose or glabrous. Both sexes lack styli. Paraprocts asymmetrical, apically setose, right with sclerotised, finger-like projection.Anterior and lateral margins of subgenital plate concave, posterior margin strongly sclerotised, rounded. Males with four genital phallomeres: first sclerite of left phallomere (L1) with two lobes separated by sclerotised cleft, rarely reduced or absent; second ventromedial sclerite of left phallomere (L2vm) strongly sclerotised, rod-like; second dorsal sclerite of left phallomere (L2d) posteriorly sclerotised, approximately triangular or blade-like, occasionally reduced or absent; second sclerite of right phallomere (R2) hook-shaped, rarely reduced to straight rod or absent.

Key to Australian Panesthia species

The following key has been modified from Roth (1977). In cases where the wings have been mutilated, wings are considered fully developed (macropterous) or partially reduced (brachypterous) if the terminal bases of the tegmina are separated by no more than the approximate width of the scutellum ( Fig. 1A, B View Figure 1 ). Wings are considered highly reduced (micropterous) if the terminal bases of the tegmina are separated by nearly the entire width of the meso- or metanotum ( Fig. 1C View Figure 1 ). The wingpolymorphic species Panesthia cribrata ( Saussure, 1864) and Panesthia australis ( Brunner de Wattenwyl, 1865) each occur twice in the key.

1. Tegmina and wings fully developed or partially reduced but reaching beyond the 1st abdominal segment, with tegmina relatively wide and not in the form of highly reduced lateral pads.…............... 2

Tegmina in the form of highly reduced lateral pads, or completely absent ………………..................….… 8

2. Anterior half of tegmina with oblique yellowish band ….........................…................……… Panesthia tepperi

Tegmina without oblique yellowish band ……......… 3

3. Hind margin of supra-anal plate toothed, denticles sometimes subobsolete .................................................... 4

Hind margin of supra-anal plate entire .........……..... 5

4. Dorsoapical portion of cercus densely setose. Anterolateral holes of abdominal segment 7 deep and widely excised. Lateral marginal hemline of supra-anal plate incomplete, subobsolete, or absent ……......................……. Panesthia ancaudellioides Dorsoapical portion of cercus with few punctuations but not setose. Anterolateral holes of abdominal segment 7 typically small. Lateral marginal hemline of supra-anal plate narrow, but complete and distinct ...........…….. Panesthia cribrata

5. Dorsoapical surface of cercus non-setose. Posterolateral angle of abdominal segment 7 hardly produced, rounded. Vertex foveolate, anterior pronotal margin widely excised with a small, broad, triangular mesal elevation (male); vertex non-foveolate, anterior pronotal margin feebly concave, without a mesal elevation (female) ..…….......................................................................…… 6

Cercus bulbous, dorsoapical half or more densely setose. Vertex non-foveolate, anterior pronotal margin with a V– or U–shaped emargination without a mesal elevation (male), or only slightly indented or entire (female) ...................…................…… 7

6. Lateral margin of abdominal segment 7 approximately straight. Body length typically ≤ 20 mm. Disc tubercles absent or subobsolete (male) …..............................................…….. Panesthia parva

Lateral margin of abdominal segment 7 sinuous, concave on posterior half. Body length typically> 20 mm. Disc tubercles distinct, weakly produced (male) .......................................... Panesthia grayi sp. nov.

7. Lateral margin of abdominal segment 7 straight or slightly concave on posterior half, caudal angle subacute ............................................. Panesthia australis

Lateral margin of abdominal segment 7 deeply concave on posterior half, caudal angle broadly rounded ................................................... Panesthia obtusa

8. Tegmina present ................................................................... 9

Tegmina and hind wings absent ................................ 14

9. Hind wings present ............................................................ 10

Hind wings absent .............................................................. 11

10. Hind margin of supra-anal plate crenulate or subentire. Dorsal surface of cercus non-setose ..... .................................................................... Panesthia cribrata

Hind margin of supra-anal plate entire. Dorsal surface of cercus densely setose .................................... .................................................................. Panesthia australis

11. Anterior pronotal margin entire, subentire or subtruncate, reflexed tubercles on each side of the midline absent, small mesal marginal tubercle present (male) or absent (female). Pronotal disc shallowly or moderately depressed. Anterolateral corners of abdominal segments 6 and 7 with deep holes ........................................................................................... 12

Anterior pronotal margin narrowly excised, lateral corners of the excision forming small reflexed tubercles, mesal marginal tubercle absent (both sexes). Pronotal disc deeply excavated with pair of widely spaced tubercles. Anterolateral corners of abdominal segments 6 and 7 without deep holes ................................. Panesthia tryoni tegminifera

12. Hind margin of supra-anal plate crenulate or shallowly undulate. Anterior pronotal disc moderately depressed, somewhat granular, disc tubercles present (male). Anterolateral holes of abdominal segments 6 and 7 extending behind anterior margin of segment as sinuous grooves. Cercus bulbous, apically rounded, dorsoapical surface sparsely or densely setose .......................... 13

Hind margin of supra-anal plate entire. Anterior pronotal disc shallowly depressed, finely punctulate, disc tubercles subobsolete or absent (male). Anterolateral holes of abdominal segments 6 and 7 not extending behind anterior margin of segment as sinuous grooves. Cercus subrectangular, dorsoapical punctulate, non-setose .................................................. Panesthia lata

13. Apex of tegmen typically fused with mesonotum. Anterolateral corner of abdominal segment 5 with small hole. Second dorsal sclerite of left phallomere broad, length approximately equal to width at base (male) ....... Panesthia juncta sp. nov.

Apex of tegmen never fused with mesonotum. Anterolateral corner of abdominal segment 5 without small hole. Second dorsal sclerite of left phallomere narrow, length greater than width at base (male) ................................... Panesthia matthewsi

14. Hind margin of supra-anal plate unevenly crenulate, teeth broad at base, tapering, closely spaced. Emargination of anterior pronotal margin narrow and angular ............. Panesthia tryoni tryoni

Hind margin of supra-anal plate dentate, teeth relatively slender, usually more widely spaced. Emargination of anterior pronotal margin wide and concave ........................................ Panesthia sloanei Remarks: The taxonomic key presented above follows Roth (1977) in including Panesthia tepperi ( Kirby, 1903) . Panesthia tepperi is unique among Australian Panesthia for the presence of a yellow band on its tegmina, as this morphology is otherwise observed exclusively in Asian taxa. Records of the species are exceptionally scarce, and it was described from a single specimen, reportedly collected from Port Darwin, Northern Territory. Tepper (1893) initially identified the specimen, which was collected by his brother circa 1874, as belonging to the pre-existing species Panesthia transversa ( Brumeister, 1838) . However, based on Tepper’s (1893) morphological description, Kirby (1903) instead described the specimen as a new species ( P. tepperi ), highlighting the interrupted yellow band on the tegmina (versus uninterrupted in P. transversa ). Panesthia tepperi was listed as a valid species in the taxonomic reviews of Princis (1965) and Roth (1977), though neither author examined the material, and similarly relied upon Tepper’s (1893) original account of the holotype. Therefore, all previous taxonomic treatments of P. tepperi have been based on a single sample. The authors are only aware of two additional specimens, labelled as originating from Mitchell River, Queensland (date unknown). Two of the four authors (HAR and JAW) have conducted extensive surveys in likely habitats around Mitchell River and Darwin without detection of the species.

This combination of divergent morphology and unverified occurrence records raises significant doubts about the taxonomic status of P. tepperi , suggesting that the three putative specimens may represent mislabelled Asian or Melanesian material. Here we provisionally treat P. tepperi as an Australian species, however we emphasise the need for future genetic analyses of the specimens to determine whether they cluster with Australian or Melanesian taxa.

More broadly, molecular phylogenetic studies have shown that Panesthia is polyphyletic with respect to the genera Caeparia ( Stål, 1877) and Ancaudellia ( Shaw, 1925) , as well as the Australian-endemic subfamily Geoscapheinae ( Beasley-Hall et al. 2021, Lo et al. 2016, Maekawa et al. 2003). Therefore, there is a clear need for a substantial taxonomic revision of Panesthiinae , although this undertaking is beyond the scope of the present study. Based on their close evolutionary affinity to the genus’ type species Panesthia angustipennis ( Illiger, 1801) , as inferred from molecular data ( Lo et al. 2016, Adams et al. 2024), we suggest that both species described here are likely to retain the generic epithet Panesthia . However, their placement should still be considered somewhat provisional, pending future taxonomic assessments.