Parathyginus Scudder, 1957

Malipatil, M. B., 2021, Revision of Australian Parathyginus with description of two new species, along with first detailed description of aedeagus in the family Heterogastridae (Hemiptera: Heteroptera: Lygaeoidea), Zootaxa 5016 (4), pp. 503-522 : 504-505

Genus Parathyginus Scudder, 1957

Parathyginus Scudder, 1957: 167 (Type species by original designation: Heterogaster signifer Walker, 1872 ). Scudder, 1962: 122 (in key). Ban, 2018: 52 , 54 (in key).

Parathyginus Dellapé & Henry, 2021 : Lygaeoidea Species File. Version 5.0/5.0. Available from: urn:lsid:Lygaeoidea.speciesfile.org:TaxonName: 489774 (accessed 1/01/2021).

Redescription. Body elongate, covered with dense silky decumbent pubescence, in addition to longer bristly setae on body and appendages generally ( Figs. 1–7 ).

Head wider than long, rounded anteriorly; punctate; tylus slightly projecting beyond juga (mandibular plates) that are laterally carinate; eyes slightly exserted with tendency to be stylate, more so in males; ocelli nearer to eyes than to each other; bucculae raised anteriorly flaplike. Antennae with antennal insertion prominent, visible from above; 1 st segment exceeding apex of head, 2 nd segment longest, 4 th longer than 1 st and subequal to 3 rd.

Thorax Pronotum wider than long, carinated laterally, with distinct transverse impression between anterior and posterior lobes, anterior lobe narrower than posterior lobe with lateral margins almost parallel; posterior margin markedly concave before scutellum. Metathoracic scent gland peritreme rounded apically. Scutellum longer than broad at base, coarsely punctate, foveately impressed at basal angles, base depressed and excavate, with distinct triradiate carina, often paler than remainder of scutellum. Legs with fore femora subapically armed with 2 or 3 small ventral spines; tibiae usually without three fuscous annulations but with or without basal and apical fuscous areas. Hemelytra extending to tip of abdomen, often exposing abdominal connexiva in females; clavus with three rows and with a few irregular punctures between inner and middle rows.

Abdomen. All spiracles ventral. All trichobothria weakly developed. Abdominal terga II–VI densely punctate (e.g., Figs. 8 & 10 ), VII without or with only a small number of weak punctures. Inner laterotergites present or absent. Scent gland scars present between terga IV–V and V–VI, latter wider than the former by about 1.5X.

Male with entire abdomen usually uniformly coloured, often connexiva only pale. Female with sterna laterally and connexiva with varying pale patches. Female with sternum IV strongly narrowed towards middle and broken in midline, ventral sutures of segments V, VI and VII curving along ovipositor, very strongly narrowed and extended inwards to anterior margin of III–IV suture ( Fig. 11 ).

Male genitalia. Pygophore with posterior margin entire or occasionally with a small median tooth. Paramere with blade gradually curved ( Fig. 13 ). Aedeagus unique, as in Fig. 15 . Basal articulatory apparatus small, partly fused with phallotheca ( Fig. 14 ). Phallotheca heavily sclerotised, short and bulbous with upper surface abruptly swollen in middle area, lower surface in lateral view gradually curved from middle to proximal and distal ends ( Fig. 16 ). Endosoma inflatable during dissection, in repose tightly folded and accommodated inside phallotheca; conjunctiva membranous, tubular and of slightly variable girth, extremely long, 4–6 X as long as phallotheca, appear turned about mid length, often with membranous lobes ( Fig. 15 ); seminal duct usually clearly visible through membranous conjunctiva, ejaculatory reservoir reduced and pigmented ( Figs. 17, 18 ); vesical seminal duct continues as a heavily pigmented and sclerotized narrow elongate plate that is strongly bent ventrally, the bent part extending as a complex structure comprising gonoporal process and associated parts ( Figs. 17, 18 ). Vesica short, may or may not have membranous lobes, and lacking processes.

Female genitalia. Ovipositor very long and slender ( Fig. 19 ). Spermatheca extremely long, thin tubular duct, irregularly coiled and without terminal apical bulb, base slightly expanded at opening to genital chamber ( Fig. 20 ).

Comments. Parathyginus differs from Hyginus Stål, 1859 , in having the triradiate carina of the scutellum usually pale and a very different spermatheca, in the possession of a carina (very faint in some) on the jugum (mandibular plate) making the head appear rounded anteiorly (rather than more pointed head in Hyginus ), and lacking in most species the three fuscous equidistant annulations to the tibiae. In Parathyginus spermatheca lacks a terminal bulb and the duct is extremely long, tubular and irregularly coiled, in Hyginus the spermatheca has a terminal bulb and the duct is relatively short and regularly twisted. Parathyginus is related to Artemidorus Distant, 1903 , in the shape of the head and in the similar type of spermatheca. However, in Artemidorus the hemelytra and abdomen are constricted, the pronotum is narrower and has a deep transverse impression which causes the anterior margin to appear raised.

Figures

FIGURES 1–4. 1, Parathyginus signifer, Lectotype male, body dorsal view; 2, Dinomachus doddi Lectotype male, body dorsal view and labels; 3, same, Paralectotype female, body dorsal view and labels; 4, Parathyginus signifer, male, body dorsal view (Iron Range, Qld).

FIGURES 5–7. Parathyginus signifer: 5, male body, lateral view; 6, 7, female body, lateral views showing variation in colour markings between specimens from Hinchinbrook Island, Qld.

FIGURES 8–13. Parathyginus signifer: 8, 9, male abdomen, tergum and sternum, roman numerals refer to abdominal tergites / sternites; 10, 11, female abdomen, tergum and sternum; 12, male, pygophore, dorsal view; 13, male, left paramere, dorsal view.

FIGURES 14–20. Parathyginus signifer:14–18, male -14, articulatory apparatus; 15, aedeagus; 16, phallotheca, lateral view; 17, 18, distal part of endosoma. 19, 20, female—19, part of ovipositor; 20, spermatheca. Abbreviations: co, conjunctiva; er, ejaculatory reservoir; ph, phallotheca; sd, seminal duct; sp, spermatheca; ve, vesica.