Panaetius Stål, 1865

Wang, Xiao-Jing, Liu, Guo-Qing & Cassis, Gerasimos, 2015, Revision of Panaetius Stål (Hemiptera: Heteroptera: Acanthosomatidae) from Australia, including the description of two new species and phylogenetic analysis, Austral Entomology 54 (4), pp. 445-464 : 446-454

Panaetius Stål

Panaetius Stål 1865: 220 (original description; type species: Panaetius lobulatus Stål 1866 by subsequent monotypy); Stål 1876: 112 (list); Lethierry and Severin 1893: 251 (catalogue); Kirkaldy 1909: 170 (catalogue); Kumar 1974: 19, 36–37 (redescription); Cassis and Gross 2002: 372 (Australian catalogue).

Ucia Walker 1867: 407 (original description; type species: Ucia mutilata Walker 1867 by monotypy); Stål 1876: 112 (synonymy).

Diagnosis

Panaetius is recognised by the following combination of characters: body small, less than 6 mm in length ( Fig. 1 ); paraclypei flat and arcuate distally, meeting in front of clypeus (Figs 1,7); AI not reaching apex of head, AII(a) longer than AII(b) ( Fig. 1 ); labium reaching beyond posterior margin of mesocoxae ( Fig. 1 ); pronotum with pair of short shelflike anterolateral processes and pair of elongate and robust humeral horns (Figs 1,7); scutellum broad basally and rounded distally; mesosternal carina weakly developed ( Fig. 1 ); external efferent system of MTG small, with obovate and laterally directed peritreme, not reaching lateral margin of evaporative area ( Fig. 8 ); abdominal basal spine strongly projected, almost reaching anterior margin of prosternum ( Fig. 1 ); parameres broad and knifelike ( Figs 2b , 3b , 4b , 5d ); aedeagus with pair of short membranous lateral conjunctival lobes ( Figs 2c,d , 3c,d , 4c,d , 5c,d ) and pair of sclerotised dorsal conjunctival processes ( Figs 2c,d , 3c,d , 4c,d , 5c,d ); vesica membranous ( Figs 2c,d , 3c,d , 4c,d , 5c,d ); pair of Pendergrast’s organs on venter of abdominal sternites VI and VII, with VII organs larger than those of VI ( Fig. 9 ).

Redescription

Body suboval in shape, with enlarged humeral horns ( Fig. 1 ). COLOURATION. Medium brown to dark brown, with darker brown markings ( Fig. 1 ). Head: medium to dark brown, sometimes with dark brown stripe along lateral margins of paraclypei and anteclypeus ( Fig. 1 ). Antennae: AI-AIV pale to dark brown, progressively darker distally. Labium: LI-LIV pale to dark brown. Pronotum: yellowish to dark brown, with dark brown markings; calli yellowish to dark brown; anterolateral processes pale brown; humeral horns reddish brown or black, sometimes one or two transverse pale brown spot(s) medially on horns ( Fig. 1 ). Scutellum: yellowish to dark brown, with dark brown markings, sometimes with longitudinal dark brown stripe on midline; V-shaped pale brown marking at apex ( Fig. 1 ). Thoracic pleura: pale to dark brown, sometimes uniformly dark brown; metapleuron with a large yellowish brown callous spot along lateral margin ( Fig. 1 ). MTG: external efferent system yellowish to dark brown ( Fig. 1 ). Hemelytra: pale to medium brown, with dark brown markings, sometimes with reddish tinge, mostly with medium brown stripe along medial fracture; membrane medium to smoky brown, sometimes with a large irregular dark brown spot near inner base of membrane, veins dark brown ( Fig. 1 ). Legs: pale to dark brown, progressively darker distally, claw black apically, sometimes tibiae with brown bands ( Fig. 1 ). Abdomen: connexiva pale to medium brown, with dark brown markings; venter pale brown with dark brown stripe laterally; spine pale to medium brown ( Fig. 1 ). VESTITURE. Dorsum mostly with moderate distribution of simple, white, adpressed setae, shorter semierect on vertex of head and decumbent hairlike setae on lateral margins of pronotum; abdominal venter with sparse distribution of simple, semierect setae. Antennae: sparsely distributed decumbent hairlike setae on AI; AII(a)-AII(b) with moderate distribution of setae; AIII-AIV with dense distribution of setae. Pronotum: mostly with white decumbent setae on lateral margins and humeral horns. Legs: uniformly pale brown; setae on femora rare; tibiae and tarsi with spinelike setae and apex of tarsi with a few hairlike setae. Abdomen: with moderate distribution of semierect setae. STRUCTURE. Head: paraclypei contiguous, arcuate (Figs 1,7). Eyes: semioval in frontal view, with medial margin straight, oval in lateral view ( Fig. 7 ). Antennae: AI shortest, not surpassing anterior margin of head; AII(a) about as 1.5–2.0× long as AI. AIII-AIV slightly wider than other segments (Figs 1,7). Labium: reaching mesocoxae ( Fig. 1 ); LI slightly wider than LII and LIII; LI shorter than ventral side of head; LII about as 2.0× long as LI; LIII slightly shorter than LII, LIV about 1.5× shorter than LII. Pronotum: anterolateral processes short and shelflike ( Fig. 7 ); pronounced humeral horns, elevated distally, apically bifid, smooth, without ridges or teeth ( Fig. 1 ). Scutellum: flat, width slightly longer than length ( Fig. 1 ). MTG: external efferent system peritreme flat, obovate, laterally ( Fig. 8b ) to posterolaterally oriented ( Fig. 8a,c,d ), evaporative areas not extensively distributed on metepisternum, not extending to apex of peritreme ( Fig. 8 ), usually without evaporative bodies on mesepimeron ( Fig. 8a,c,d ), rarely so ( Fig. 8b ). Legs: hind femora slightly broader and longer than mesofemora; tarsi narrow, tarsal segment I short, segment II ca. 1.5–2.0× longer than segment I. Abdomen: posterior angles of connexival segments short; abdominal spine of sternite III reaching between anterior margins of procoxae and propleuron ( Fig. 1 ); pair of Pendergrast’s organs on venter of abdominal sternites VI and VII, with VII organs larger than those of VI ( Fig. 9 ). Male genitalia: pygophore transverse, and wing-shaped, with genital opening broad, with two small black processes and setose patches on ventral rim ( Figs 2a , 3a , 4a , 5a ); parameres knifelike, with short stem, with crown moderately broad to greatly broad, mostly with black impressed line and hairlike setae medially ( Figs 2b , 3b , 4b , 5b ); aedeagus with phallotheca short and sclerotised; endosoma divided into a pair of sclerotised dorsal processes, with pair of lateral conjunctival lobes, rarely with pair of more distal central conjunctival lobes, vesica membranous ( Figs 2c,d , 3c,d , 4c,d , 5c,d ). Female genitalia: first gonocoxites large, posterior margin almost straight; sclerotised rings thin, contiguous medially, weakly sclerotised; vaginal intima weakly expanded; spermatheca moderate size to elongate, with capsula seminalis of moderate size, obovate, recurved ( Fig. 6 ).

Distribution

Panaetius is endemic to Australia, and most species are found in the coastal regions of eastern Australia. All four species are broadly distributed and each is known from Queensland and New South Wales, with P. lobulatus also known from Victoria and Tasmania ( Fig. 11 ).

Remarks

Kumar (1974) reported that Panaetius is similar to Monteithiessa but can be readily distinguished from it by the first antennal segment not extending beyond the paraclypei and the paraclypei not extending beyond the apex of the clypeus. In comparison, AI reaches beyond the paraclypei and the paraclypei are contiguous anteriad to the clypeus in Monteithiessa . Panaetius also differs from species of the Blaudusini genera Andriscus , Duadicus , Hiarchas and Stauralia by the pronotum having two pairs of processes, with the anterolateral pair developed. In the other four genera, the pronotum has the anterolateral pair of processes absent or minute.

In all species of Panaetius , the parameres are broad and knife-shaped, the aedeagus has a pair of elongate dorsal sclerotised conjunctival processes (e.g. Fig. 2d ), a pair of short lateral membranous conjunctival appendages (e.g. Fig. 2d,e ), and the vesica is membranous (e.g. Fig. 2d,e ). In the female, the capsula seminalis is small, short and curved ( Fig. 7a–d ).

In Andriscus the paramere is almost triangular, the aedeagus has two pairs of processes, and the vesica is membranous, and in the female the capsula seminalis is long, hatlike and medially recurved. In Duadicus , the paramere is ‘L’ shaped and almost rectangular in apical view, the aedeagus has a pair of lateral conjunctival lobes, and the vesica is sclerotised and ‘C’ shaped, whereas the capsula seminalis of the female is small and oval. In Hiarchas , the paramere is subtriangular, the aedeagus has two pairs of conjunctival lobes, the vesica is membranous, and in the female the capsula seminalis is small and oval. In Stauralia , the paramere is almost triangular in apical view, the aedeagus has one pair of conjunctival lobes, and the vesica is short and sclerotised, and in the female the capsula seminalis is small and oval.

Key to species of Panaetius Stål

1 Humeral horns apically undivided, smooth, devoid of ridges or teeth ( Fig. 1 ); MTG peritreme laterally oriented, mesosternum with evaporative bodies ( Fig. 8b ); parameres moderately broad ( Fig. 3b ); aedeagus with short membranous ventral conjunctival lobes ( Fig. 3c,d )........................... P. laevicornis sp. nov.

– Humeral horns apically divided, with prominent ridges or teeth ( Fig. 1 , e.g. P. eliasi ); MTG peritreme posterolaterally oriented, mesosternum without evaporative bodies (e.g. Fig. 8a ); parameres greatly broadened (e.g. Fig. 2b ); aedeagus without ventral conjunctival lobes (e.g. Fig. 2c,d )........................2

2 Humeral horns uniformly black ( Fig. 1 ); anterolateral processes of pronotum narrow with apices rounded ( Fig. 7a ); parameres apically emarginate ( Fig. 2a ) .................................... P. eliasi sp. nov. – Humeral horns mostly brown and yellowish brown ( Fig. 1 , P. lobulatus ); parameres apically rounded (e.g. Fig. 2c ).........................................................3

3 Anterolateral processes of pronotum broad (Figs 1,7c); humeral horns relatively short ( Fig. 1 )...................................... P. lobulatus Stål – Anterolateral processes of pronotum slender (Figs 1,7d); humeral horns greatly elongate ( Fig. 1 )................................... P. trabifer Horváth

Figures

Fig. 1. Habitus images of species of Panaetius. Scale bar = 1 mm.

Fig. 8. External efferent system of metathoracic glands of Panaetius spp. (a) P. eliasi sp. nov., (b) P. laevicornis sp. nov., (c) P. lobulatus, (d) P. trabifer.

Fig. 2. Panaetius eliasi sp. nov. male genitalia: (a) pygophore (ventral view), (b) paramere, (c) aedeagus (lateral view), (d) aedeagus (dorsal view). C, conjunc- tiva; DP, dorsal conjunctival lobes; LCL, lateral conjunctival lobes; V, vesica. Scale bar = 0.1 mm.

Fig. 3. Panaetius laevicornis sp. nov. male genitalia: (a) pygophore, (b) paramere, (c) aedeagus (lateral view), (d) aedeagus (dorsal view). C, conjunctiva; DP, dorsal conjunctival lobes; LCL, lateral conjunctival lobes; V, vesica.Scale bar = 0.1 mm.

Fig. 4. Panaetius lobulatus male geni- talia: (a) pygophore, (b) paramere, (c) aedeagus (lateral view), (d) aedeagus (dorsal view). C, conjunctiva; DP, dorsal conjunctival lobes; LCL, lateral conjunc- tival lobes; V, vesica. Scale bar = 0.1 mm.

Fig. 5. Panaetius trabifer male genitalia: (a) pygophore, (b) paramere, (c) aedeagus (lateral view), (d) aedeagus (dorsal view). C, conjunctiva; DP, dorsal conjunctival lobes; LCL, lateral conjunctival lobes; V, vesica. Scale bar = 0.1 mm.

Fig. 9. Pendergrast’s organs of Panaetius spp. (a) P. eliasi sp. nov., (b) P. laevicornis sp. nov., (c) P. lobulatus, (d) P. trabifer.

Fig. 7. Anterolateral processes of pronotum of Panaetius spp. (a) P. eliasi sp. nov., (b) P. laevicornis sp. nov., (c) P. lobulatus, (d) P. trabifer.

Fig. 6. Female genitalia of Panaetius spp. (a) P. eliasi sp. nov., (b) P. laevicornis sp. nov., (c) P. lobulatus, (d) P. trabifer. CS, capsula seminalis; SR, sclerotised rings; TVI, thickenings of vaginal intima; 1st G, first gonocoxite. Scale bar = 0.1 mm.

Fig. 11. Distribution maps of Panaetius species.