Pseudolaryngodus, Malipatil & Gao, 2019

Malipatil, M. B. & Gao, Cuiqing, 2019, A new genus and new species of Myodochini from Australia (Hemiptera: Heteroptera: Rhyparochromidae), Zootaxa 4565 (1), pp. 117-123 : 118-120

Genus Pseudolaryngodus gen. nov.

( Figs. 1 , 2 )

Type-species: Pseudolaryngodus spectabilis sp. nov.

Body narrow, elongate. Head porrect, excluding eyes about twice as long as wide, anterior to eyes parallel sided; buccula short, flaplike anterior of antennal base. Antennae with 1 st segment short, heavily incrassate, slightly exceeding tylus, atenniferous tubercle simple. Labium almost reaching hind coxae, 1 st segment nearing but not reaching base of head. Labrum short, about ¼ as long as 1 st labial segment.

Thorax. Pronotum with anterior collar narrow and lowered, anterior lobe about 3 times as long as posterior lobe. Scutellum triangular, with distinct Y-shaped impression, median keel well developed in apical half, basal disc area almost flat. Legs with fore femora heavily incrassate for middle 2/3, in apical ½ ventrally armed with spines in 2 indistinct series, fore coxae with one minute spine, fore tibia curved in basal 2/3, only about 2/3 as long as fore femur, unarmed, other femora slightly incrassate and unarmed.

Hemelytra fully covering abdomen, parallel sided along corial margin; covered with coarse fuscous punctures as follows: clavus with inner and outer rows of almost complete rows, inside these rows with one incomplete irregular row, corium with one almost complete inner row parallel to clavus, other areas of corium with irregular scattered punctures. Thoracic pleura almost impunctate. Metathoracic scent gland auricle very narrow, evaporative area small, not extensive.

Abdomen with spiracles II, III and IV dorsal on connexiva (= outer lateral tergites, olt), spiracles of other segments ventral on sterna. Dorsum with inner laterotergites absent; tergites III–VI covered with very dense fine regular punctures, and outer laterotergites covered with fine punctures, olt VII posteriorly fused with tergite VII; sutures between tergites III–IV moderately, IV–V and V–VI strongly curved caudad mesally, and with scent gland scars between III–IV almost twice as wide as those between IV–V and V–VI which are subequal. Abdominal trichobothria placed submedially on sternites III & IV and sublaterally on sternites V–VII, with usual trichobothrial numbers: 3:3:3:3:2. Suture between sternites IV–V slightly curved, directed anterolaterally in an arcuate fashion, and not reaching abdominal margin. Anterior margin of sternite VII with a median apodeme, extending to about ½ length of sternite VI.

Male genitalia. Pygophore drawn into abdominal segment VIII, genital opening dorsal, covered by abdominal tergite VIII in repose; opening with a pair of broad lateral lobes or projections; posterior lip or edge entire. Paramere with dorsal and ventral lobes, and blade sickle-shaped. Aedeagus with basal apparatus heavily sclerotized, phallotheca with sclerotized irregularly shaped band that is more extensively broad and long on dorsal aspect than on ventral aspect; endosoma with distinct conjunctiva and vesica, conjunctiva with well-developed and sclerotized ejaculatory reservoir with distinct body and pair of wings, in addition with a pair of elongate triangular shaped heavily sclerotized holding sclerites with associated membranous lobes; helicoid process with gonoporal process thin, twisted about seven times.

The overall structure of the aedeagus appears to match with “ Type I” phallus of Mydochini as defined by Harrington (1980); this type is characterized by a well developed reservoir with anterolaterally directed wings and long, slender parentheses-like holding sclerites, and usually unadorned conjunctiva and vesica.

Etymology: From the Greek, pseudo, false, alludes to this bug’s false resemblance to the udeocorine genus Laryngodus .

Discussion. Pseudolaryngodus gen. nov. resembles Laryngodus in elongate narrow body shape and overall colour, and shares several characters that are useful at tribal level ( Figs. 3 , 4 ). These characters are porrect head, rounded pronotum, abdominal sternites IV–V fused, suture curving cephalad, not reaching lateral margin of abdomen, spiracles II, III and IV dorsal on connevixum, others ventral on sternum; aedeagus with conjunctiva not spined ( Sweet 1967). Based on these characters, Pseudolaryngodus can be assigned to either of the tribe Udeocorini or Myodochini , as defined by Sweet (1967). However, Laryngodus has inner laterotergites present and distinct as very narrow sclerotised plates particularly on abdominal segments III–V (see Fig. 3b ), while these are absent in Pseudolaryngodus ( Fig. 1c ). Based on this character, the new genus is here placed in the tribe Myodochini , as characterized by Sweet (1967).

In the generic key to Australian Myodochini ( Malipatil 1978) , Pseudolaryngodus runs to couplet 14, that separates genera Pseudopachybrachius Malipatil and Paraeucosmetus Malipatil. But the new genus does not match either of these genera. Pseudolaryngodus has the anterior pronotal lobe about three times as long as the posterior lobe and well developed holding sclerites on the aedeagus, whereas both Pseudopahcybrachius and Paraeucosmetus have the anterior pronotal lobe never longer than twice as long as posterior lobe, and lack the holding sclerites on their aedeagus.

In generic key to world Mydochini by Harrington (1980), Pseudolaryngodus keys out to the old world genus Pamerana Distant by sharing several characters including the Type I phallus of male genitalia, the emergent mesepimeron, and the double-ranked fore femoral spines. However, the new genus can be readily distinguished from Pamerana by the absence of the characteristic marked deep median groove on posterior lip or edge of the pygophore.

Figures

FIGURE 1. Pseudolaryngodus spectabilis gen. et sp. nov. a, HOLOTYPE male, habitus, dorsal view; b, same, ventral view; c, PARATYPE male, abdominal dorsum; d, same, abdominal venter. Abbreviations: sgs, scent gland scars; sp, spiracles; tb, trichobothria.

FIGURE 2. Pseudolaryngodus spectabilis gen. et sp. nov. PARATYPE male. a, pygophore, posterodorsal view; b–e, left paramere, four different aspects; f, aedeagus, lateral view; g, same, dorsal view. Abbreviations: b, body; ba, basal apparatus; c, conjunctiva; dl, dorsal lobe; gp, gonoporal process; hp, helicoid process; hs, holding sclerite; ll, lateral lobe; ml, membranous lobe; n, neck; p, phallotheca; vl, ventral lobe; w, wing.

FIGURE 3. Laryngodus luteomaculatus, male. a, habitus, dorsal view; b, abdominal dorsum; c, abdominal venter. Abbreviations: ilt, inner laterotergite; sp, spiracles.

FIGURE 4. Laryngodus luteomaculatus, male. a, pygophore, posterodorsal view; b, aedeagus, dorsal view; c–f, left paramere, four different aspects.