Sanganus Distant, 1909

Genus Sanganus Distant, 1909 View in CoL

Sanganus Distant, 1909:389 (gen.nov., description). Type species: Sanganus jenseni Distant, 1909 , by original designation.

Sanganus : Kirkaldy (1909): 366 (catalogue).

Sanganus : Kumar & Ghauri (1970): 19-20, 30 (key, genitalia).

Sanganus : Rolston et al. (1993): 75 (catalogue).

Diagnosis. Sanganus shares the characteristics of the tribe Eusthenini as mentioned by Horváth (1900): Pronotum posteriorly not produced; scutellum subequilateral, frenum extended towards apex; lateral margins of connexiva not bifurcated; antennae 4-segmented, male genital segment without particular characteristics; tarsi 3-segmented.

The genus is distinguished from other members of the tribe by a combination of the following characteristics: Maximum width of pronotum larger than or equal to combined median length of head, pronotum, and scutellum; margins of fourth abdominal segment not ampliated laterally; mandibular plates meet in the middle; metasternal carina no more than half the width of hind coxae, only slightly elevated; posterior tibiae not noticeably curved; postero-lateral margins of seventh abdominal segment only slightly produced into pointed structures. The characteristic “anterior margin of pronotum slightly wider than posterior margin” mentioned in the key of Kumar & Ghauri (1970) only applies to S. jenseni . Although Sanganus is certainly closely related to Pseudopycanum , they differ in the characteristics given in the following identification step which may partly amend the key of Kumar & Ghauri (1970, p. 16, step 6): 6. Body size 20 mm ( Fig. 1 D). Lateral margins of abdomen distally more or less evenly diverging; 7 th abdominal segments posteriorly produced into long, diverging and distally pointed processes thus forming the broadest part of the body; dorsal and ventral laterotergites VII of the same size ( Fig. 10 D). Evaporatorium of the scent efferent system not extending on mesopleuron ( Kment & Vilímová 2010 and own observations). Femora ventro-distally with reduced knobs. .... ............................. Pseudopycanum Bergroth, 1891 – Body size larger than 23 mm ( Fig. 1A- C). Lateral margins of abdomen sinuate; ventral laterotergites VII distally moderately produced, distinctly larger than dorsal laterotergites VII. Evaporatorium of the scent efferent system extending on mesopleuron ( Fig. 8A- C). Femora ventro-distally with two large spines. ............... .......................................... Sanganus Distant, 1909

Redescription

Colouration. Dried specimens ochreous to saddle brown.

Head. Eyes distinctly protruding outwards; ocelli situated proximally to an imaginary line between posterior edges of the eyes; distance between ocelli about half the distance between the inner margins of the eyes. Mandibular plates longer than tylus, medially contiguous in front of the tylus ( Fig. 2). Antennae 4-segmented; first segment smallest, slightly surpassing apex of head; second and third segments subequal in length, third segment distally slightly thickened; fourth segment longest; antennifer visible from above and nearly straight ( Fig. 3). Bucculae short and parallel-sided; rostrum 4-segmented, not reaching beyond metacoxae; first labial segment surpassing posterior terminations of bucculae; second segment longest; third and fourth segments subequal in length.

Pronotum ( Fig. 4). Humeral angles explanate and produced antero-laterad, apices rounded; anterior angles dentate; posteriorly hardly produced; with fine and coarse punctures; calli almost impunctate and separated from each other. Maximum width of pronotum greater than or equal to combined median length of head, pronotum, and scutellum.

Scutellum ( Fig. 5). Subisosceles, apically spatulate and rounded; moderately dense punctate except apex.

Hemelytra. Membrane distally semicircular; with four to six basal cells, mesially quadrangular to hexangular, the lateral cell subtriangular and distally extended ( Fig. 6).

Sternum. Mesosternal carina medially sulcate. Metasternal xyphus not produced anteriorly; metasternal carina width not exceeding half the width of metacoxae, taxonomically diagnostic ( Fig. 7).

Metathoracic scent efferent system ( Fig. 8; terminology adopted from Kment & Vilímová, 2010). Ostiole close to metacoxal cavity, slit-shaped, peritremal lobes nearly parallel to each other. Metathoracic spiracle rather small, hardly visible, located laterally of an imaginary median line of metapleuron. Metapleural evaporatorium developed along ostiolar groove, reaching laterad beyond spiracle. Mesopleural evaporatorium located between mesopleural suture and lustrous median area of posterior margin of mesopleuron.

Legs. Femora and metatibia straight; pro- and mesotibia slightly curved inwards. Femora ventro-distally with smaller inner spine and larger outer spine; these spines larger on meso- and metafemora ( Fig. 9). Tibiae longitudinally sulcate. Tarsi 3-segmented.

Abdomen. Connexivum laterally curved. Distal angles of ventral laterotergites II- VI slightly protruding. Ventral laterotergites VII latero-distally distinctly acuminate and considerably larger than dorsal laterotergites, meaning that the suture is visible from above ( Fig. 10). Ribes et al. (2006) introduced the term ‘connexival groove’ for this suture and discussed its taxonomic value.

Male genitalia. Pygophore subtriangular in ventral view, lateral margins diverging distally, distal margin wave-like with medial notch ( Fig. 11). Parameres blade-shaped, apophysis regularly curved inwards, sensory lobe with long, densely arranged setae; apophysis at the base with a long seta with approximately apophysis length ( Fig. 12). Aedeagus with two pairs of membranous and sclerotized conjunctival appendages, respectively ( Fig. 13). The male of S. quadrangularis spec.nov. was not traceable.

Female genitalia. Gonocoxites VIII nearly flat, sutural margins juxtaposed, posterior margins slightly convex. Visible parts of laterotergites VIII elongated and triangular, spiracles exposed. Laterotergites IX subquadrangular or rhomboid, sutural margins diverging distally ( Fig. 14). Spermatheca (terminology adopted from Kocorek & Danielczok-Demska 2002). Typically pentatomoid, but lacking the sclerotized rod characteristic of the Pentatomidae ( Rider 2006) . Spermatheca differentiated into three distinct regions ( Fig. 15): apical seminal receptacle developed as spherical bulb, connected by a basal neck-like region; intermediate pumping region delimitated by strongly sclerotized flanges with proximal flange flat and distal flange cup-like; spermathecal duct with a median bulbous dilatation, distal duct narrow, proximal duct wider and lined with annular thickenings.

Biology. Unknown, most likely arboricolous and phytophagous species.

Etymology. The genus name ‘Sanganus’ is most likely the latinized form of the type locality Sangasanga located on Borneo Island. The gender is masculine.

Distribution ( Fig. 17). Sanganus is a tropical genus distributed in the Oriental region ranging from Malaysia and Western Indonesia to the Philippines.