Tychius filirostris Wollaston

Caldara, Roberto & Aguín-Pombo, Dora, 2008, A new synonym and new records of Tychiini (Coleoptera, Curculionidae) from Madeira Archipelago and Selvagens Islands, Zootaxa 1781, pp. 63-66 : 63-64

Tychius filirostris Wollaston

Tychius filirostris Wollaston, 1854: 346 ; 1857, 111; Caldara 1990: 142. Tychius colonnellii Caldara, 1991: 185 syn. n.

Material examined. Porto Santo, Campo de Cima, 3.vi.2000, leg. D. Aguín Pombo, 1 male, 1 female (coll. University of Madeira).

The two new specimens differ a little from each other, since the male is characterized by elongate subrectangular elytra and a dorsal vestiture of nearly unicolorous whitish-grey scales, whereas the female has shorter, oval elytra and the dorsal vestiture medially with reddish brown scales and laterally with whitish ones. Due to these characters, the female is very similar to the holotype of T. filirostris as redescribed by Caldara (1990), whereas the male seems intermediate between the holotype of T. filirostris and that of T. colonnellii , a taxon described from Teno at Tenerife and collected on Lotus glaucus Aiton ( Caldara 1991) . The same variability was found in other short series of specimens from the Canary Islands examined after the description of T. colonnellii ; those collected in Tenerife (Lomo del Mormillo, on Lotus sp., leg. M.G. Morris) are similar to the holotype of T. filirostris whereas those collected at La Palma Island (Tagoja Mt., on Lotus campylocladus Webb & Bert. , leg. M.G. Morris) are more similar to the type series of T. colonnellii . Due to a lack of differences other than the shape of the elytra and the colour of the dorsal vestiture, we interpret all these specimens as belonging to a single variable taxon, the holotypes of T. filirostris and T colonnellii representing the two extremes of the range of its variability. We therefore conclude that T. colonnellii is a junior synonym of T. filirostris . Moreover, it is noteworthy that we examined also one male Tychius specimen collected on Selvagen Pequena Island (leg. A. Serrano), from where no species of Tychius were previously reported; this specimen has a very dense elytral vestiture but is otherwise similar to the holotype of T. filirostris .

The two specimens from Porto Santo were collected on the north-eastern coast of the island on grasses growing on sandy ground near a cliff, at about 90 m altitude and close to a garbage station. Porto Santo is a tourism resort, mainly for habitants of Madeira, but recently there has been intensive construction to increase the number of hotels and other facilities (e.g,. golf courses, roads, etc.) to attract foreign tourism. This has resulted in great modification of natural habitats. Coastal habitats, especially those of T. filirostris , are under great pressure and measures should be undertaken to avoid the loss of this species on this Island.