Cottothucha Drake and Poor, 1941

Runagall-Mcnaull, Aidan & Cassis, Gerasimos, 2013, Systematics of the lace bug genus Cottothucha Drake and Poor (Insecta: Hemiptera: Heteroptera: Tingidae) with description of the first Australian species and its exaggerated nymph, Zootaxa 3640 (3), pp. 395-408 : 398-399

Cottothucha Drake and Poor, 1941

Type Species. Cottothucha oceanae Drake and Poor, 1941 by original designation.

Diagnosis. small to medium size, males (BL 2.08–3.61), females (BL 2.71–3.78); AI shorter than interocular distance; pronotum with an exaggerated pronotal cyst on medial carina, occupying entire length of pronotum, anteriorly projected over head; paranota either uniseriate or biseriate, subcontinguous medially with pronotal cyst; costal area broad with areolae greatly enlarged.

Redescription. COLOURATION ( Fig. 4 ). Pale cream to dark brown, sometimes variable, more so on pronotal cyst and areolae veins. Head and abdomen pale cream to dark brownish black. Antennae and legs uniformly tan. Eyes black. Areolae membranes of hemelytra and pronotal structures mostly pale cream or translucent, less so unevenly darkened. Areolae veins, thorax and abdomen white to dark brownish-black. VESTITURE. Antennae with hairlike setae on AIII and AIV. Short, bristlelike setae on ventral surface of second tarsal segment, sometimes also on tibiae; setae with flattened leaflike apex. STRUCTURE. Head: cephalic spines variable; antennae slender, elongate; bucculae prominent, extending beyond anterior margin of head and posteriorly slightly beyond lateral part of collum; areolae small. Mesosternum: lace structure robust, areolae small and punctulate; labial carinae widely spaced, subequal to metasternum. Antennae: AI twice as long as AII; AIII elongate, slightly longer than pronotal width. Labium: moderately long to elongate in length, extending to abdomen in some species. Pronotum ( Fig. 2 ): broad, lateral margins rounded, prominent cyst on medial carina, covering majority of head and dorsal section of collum, terminating at posterior tip of pronotum; large subquadrate areolae regularly or irregularly arranged, areolae very large on dorsal surface, becoming smaller at their base in some species; medial carina greatly reduced, uniseriate; paranota present, reflexed, upturned and adpressed against pronotal cyst, uniseriate or biseriate; lateral carinae present, uniseriate, vestigial or enlarged, mostly hidden by upturned paranota; collar region reduced; collum and thoracic pleura and sterna punctuate and heavily sclerotised, carinae, cyst and paranota papery. Abdomen: ovoid in shape, rounded ventrally; dorsal surface flattened, sharp rim around margin of dorsal surface. Legs: femora and tibiae usually subequal in length, femora greater in diameter, tibiae tapered proximally. Hemelytra ( Fig. 4 ): mostly subrectangular in shape; prominent costal area, sometimes reflexed upwards, often broad, areolae quadrate, uniseriate sometimes with extra areolae; hypocostal vein carinate ventrally; R+M vein depressed anteriorly; greatly reduced subcostal area, punctuate, sometimes depressed; discoidal area reduced in size with small areolae; sutural area broad, areolae generally large and subquadrate. Male genitalia ( Fig. 1 ): aedeagus simple, stout, possessing an elongate U-shaped spicule, without additional free endosomal sclerites; parameres simple, C-shaped ( Fig. 1 ).

Biology and host plant relationships. Cottothucha is found on species of tropical monocotyledonous flowering plants belonging to the families Araceae and Pandanacae.

Distribution. Cottothucha is comprised of three species and is found in tropical North Queensland, Papua New Guinea, the Philippines and the Moluccas (Drake & Poor 1941; Froeschner 2001; Guilbert 2006) (Fig. 3).

Remarks. The Litadeini sensu lato are morphologically heterogeneous, including species with and without pronotal processes, and/or expanded or relatively narrow hemelytra. Within the litadeine taxa that are found in the Indo-Malayan and Australian (including Pacific island) regions, the genera Cottothucha , Oecharis and Holophygdon , possess superficially similar exaggerated pronotal cysts, and are putatively closely related. Cotthothucha can be differentiated from the latter two taxa by the pronotal cyst being attached to the medial carina and not being derived from the paranota. The paranota are moderately expanded and reflexed in Cottothucha , are restricted to the lateral regions of the pronotum and are flattened against the ventral surface of the pronotal cyst. In Oecharis and Holophygodon, the paranota are greatly expanded, reflexed and strongly convex, meeting at the dorsal midline and forming a cyst resembling that of Cottothucha , but which we consider to be of different origins.

The question of the monophyly of the tribe Litadeini is a broader question that requires more exhaustive sampling of putative ingroup taxa. Guilbert (2001) declared that the tribe Litadeini is paraphyletic on the basis of a phylogenetic analysis that included two Litadeine taxa only. Further sampling is necessary to support this conclusion, and we are of the view that at least some the Australasian species of the tribe are strongly allied. Froeschner (1969) revised the use of the Drake and Ruhoff’s (1965a) original diagnosis of the Litadeini , rejecting the use of an “enormously swollen” 2nd tarsal segment that is ovate in outline and having a concave ventral surface as diagnostic for the tribe. The impact of altering the 2nd tarsal segment character on the monophyly of the Litadeini is yet to be analysed. Without a more comprehensive phylogenetic assessment of Litadeine taxa available, we maintain Cottothucha in the tribe Litadeini .

Figures

FIGURE 1. Male genitalia of Cottothucha species. a, d: C. minor; c, e: C. kalathis n. sp.; b, f: C. oceanae. a, b, c: aedeagus, dorsal view. d, e, f: right paramere, dorsal view. Scale = 100 μm

FIGURE 2. Pronotal structure comparison of Cottothucha species. a: C. kalathis, body, lateral view (50 μm); b: C. kalathis, pronotal cyst, dorsal view (50 μm); c: C. minor, body, lateral view (50 μm); d: C. minor, pronotal cyst, view dorsal (50 μm); e: C. oceanae, body, lateral view (100 μm); f: C. oceanae, pronotal cyst, dorsal view (100 μm).

FIGURE 4. Habitus of Cottothucha species: C. kalathis n. sp., C. minor, C. oceanae. Scale = 1 mm.