Ptomaphaginus isabellarossellini Schilthuizen, Njunjic & Perreau

Schilthuizen, Menno, Perreau, Michel & Njunjic, Iva, 2018, A review of the Cholevinae from the island of Borneo (Coleoptera, Leiodidae), ZooKeys 777, pp. 57-108 : 68-71

Ptomaphaginus isabellarossellini Schilthuizen, Njunjic & Perreau sp. n. Figures 5e, 7a, b, 9e, 10c

Material.

Holotype: Malaysia, Sabah, Mt. Kinabalu National Park, Bukit Ular Trail (low), 1800 m elev., multistratum evergreen forest, 2 fish traps, 07-11.xi.1987 (leg. Krikken & Rombaut, RMNH.INS.1086160), male. Paratypes: Sabah. Mt. Kinabalu National Park, Bukit Ular Trail (low), 1800 m elev., multistratum evergreen for est, 2 fish traps, 07-11.xi.1987 (leg. Krikken & Rombaut, RMNH.INS.1086161-1086164), 4 females.

Description.

Large (3.3-4.0 mm), winged. Elytra, legs and basis and tip of the antennae dark reddish brown, pronotum, head and antennomeres 5-10 nearly black. Pronotum 1.6 times as wide as long, caudal angles clearly extended, as wide as the elytra at the shoulders. Elytra slender, slightly convex, 1.5 times as long as wide (length measured from the caudal tip of the scutellum to the apex of the elytra). Elytral apex in the female gradually rounded and joining the suture at a right angle; in the male more acute, meeting the suture at a sharp angle, and with a distinct bunch of thick, black, outwardly-curved, spine-like setae. Wings present. Body otherwise covered with dense light grey setation. Male tarsi strongly dilated, tarsomeres 1-4 jointly twice as long as wide. Female tarsi not dilated. Aedeagus very strongly curved ventrad, very convex, with a distinct dorsal keel; apex trilobate; stylet very long and thin, hair-like. Spermatheca semicircular, spermiduct extremely long (in extended condition probably at least 5 mm), consisting of ca. 30 360° loops.

Differential diagnosis.

Among Sabah Ptomaphaginus , and more generally, very distinctive by its large size, dark colouration (but see below under Remarks), the spine-like setae on the male elytral apex, and the uniquely shaped aedeagus (the basic design of which, with two lateral flaps at the apex, resembles that of the P. bryanti group, as well as non-Bornean species like P. sinuatus Schilthuizen, 1984). The conspicuous bunch of spines at the elytral apex in the male is shared with three other non-Bornean species, viz. P. riedeli Perreau, 1995, P. pilipennis Perreau, 1991 and P. pilipennoides Perreau, 1991, which, however, differ strongly from P. isabellarossellini in aedeagal shape. In other Bornean species, P. bryantioides and P. similipes , stronger setae at the male elytral apex can also be discerned, but never as conspicuous as in P. isabellarossellini .

Habitat and distribution.

Only known from the lower montane forest around Kinabalu Park Headquarters.

Remarks.

It should be noted that specimens of the normally rusty-coloured P. scaphaner Szymczakowski, 1972 from the same collection sample as P. isabellarossellini are also nearly black. This may mean that the dark colouration of P. isabellarossellini is a preservation artefact.

Etymology.

Named in honour of the actress and biologist Isabella Rossellini, whose short movies and stage performances on animal reproduction have popularized theories on the evolution of genitalia. In P. isabellarossellini , the extremely long penis stylet in the male and similarly long spermiduct in the female suggest a long history of sexually antagonistic coevolution, one of the types of selection that appears in Rossellini’s 'Green Porno’ series on SundanceTV ( Schilthuizen 2014).