Piezosternum (Piezosternias)

Nicolas, Vincent, Carapezza, Attilio, Rider, David A. & Kment, Petr, 2024, New records, diagnostics and preliminary checklist of the superfamily Pentatomoidea (Hemiptera: Heteroptera) from the Comoro Islands, Zootaxa 5481 (1), pp. 1-29 : 17-18

Piezosternum (Piezosternias) sp.

( Figs. 33–35 )

Material examined. MAYOTTE: Longoni , 29.ix.2023, photo, A.Baglan lgt., P.Kment det. ; Tsararano , 12.854602°S, 45.154866°N, 176 m a.s.l., on Cucumis sativus , 2.v.2023, 1♂, 3♀, T. Ramage lgt., P. Kment det. ( TRCF) .

Biology. In Mayotte frequently clustered on the stems of Cucumis sativus ( Cucurbitaceae ) being its pest (V. Nicolas and T. Ramage, pers. observ.). Also found on Mikania capensis ( Asteraceae ) (V. Nicolas, pers. observ.).

Notes. Based on available photographs ( Figs. 33–35 ), the specimens from Mayotte have the pronotum projected backwards and the apex of the scutellum is not grooved, with a median carina reaching its apex, which corresponds to P. calidum (Fabricius, 1787) in its present sense (see Schouteden 1905b). There are two subspecies recognised within P. calidum , which are distinguished on the basis of the shape of the posterior margin of the male genital capsule, which is broadly rounded in P. c. calidum and more angulate in P. c. breddini Schouteden, 1905 . Schouteden (1905b) also provided line drawings of the posteroventral areas of the male and female abdomen, also showing differences in the shape of the posterolateral angles of the laterotergites, which are short and nearly rectangular in P. c. calidum , and longer and more sharp in P. c. breddini . However, Schouteden (1905b) wrote about the status of the two taxa [translation from French]: ‘I do not believe that P. breddini should be made a distinct species, because we find transitions to P. calidum to which I attach it as a subspecies;—the ♂ segment is always more narrowed but to variable degrees and the height of the sternal keel is sometimes but very rarely stronger in P. calidum than P. breddini ; but almost always it declines more gradually in P. calidum . I would point out in passing that no importance should be attached to the difference in shape of the ventral segments in figs. 66 to 70, these are purely individual differences.’ Mancini (1937, 1939), Blöte (1945) and Leston (1952) considered P. breddini merely a variety of P. calidum, Strand (1910) , Villiers (1952b, 1956) and Medler (1980) treated it as a valid species. Wagner (1965) and Linnavuori (1982a,b) accepted it as a subspecies, but none of the authors provided any taxonomic background for their decision. As the differences in the shape of the genital capsule and the widely sympatric distribution of both taxa in the tropics of the African mainland ( Rolston et al. 1993) suggests their specific status; this problem is in urgent need of revision. Based on the produced posterolateral angles of laterotergites, photographs of this taxon suggests that it belongs to P. c. breddini . However, the dark coloured tibiae of one of the photographed specimens from Mayotte ( Fig. 33 ) does not occur in continental specimens of any of the subspecies (Ph. Magnien, pers. comm.). We thus identify the specimens from Mayotte as Piezosternum (Piezosternias) sp., and without precise species assignment.

Figures

FIGURES 30–35. Habitus of Comoro Scutelleridae and Tessaratomidae: 30—Hotea denticulata Stål, 1865, 31–32—Calidea sp., 33–35—Piezosternum (Piezosternias) sp. (scale bar on Figs. 34–35 = 10 mm). Photos:V. Nicolas (30), P. Vergnaud (31–32), A. Baglan (33), T. Ramage (34–35).