Palorus subdepressus (Wollaston, 1864)

Palorus subdepressus (Wollaston, 1864)

Materials examined. Costanța County, Dumbrăveni (near), 43.9355°N / 27.9952°E, 16.IX.2022, pasture— at light, Cosmin-Ovidiu Manci leg. (5 specimens), COMC ( Fig. 2 View FIGURE 2 , Fig 3 C View FIGURE3 ) GoogleMaps ; IaȘi County, Dobrovăț (near), 46.9978°N / 27.6757°E, 7.X.2022, forest—dead wood related, Cosmin-Ovidiu Manci leg. (1 specimen), COMC GoogleMaps .

Collecting conditions. Specimens from Dumbrăveni were collected at the light in an area intensively grazed just at the edge of Dumbrăveni forest. The specimen collected near Dobrovăț was found under the bark of a dead common hornbeam ( Carpinus betulus ).

Distribution. Species of Afrotropical origin, now cosmopolitan ( Rees 2007; Bousquet et al. 2018). For a detailed distribution in Europe see Iwan et al. (2020). Romania is a new country record.

Notes. Palorini Matthews, 2003 includes one other Palorus species known from Romania: P. depressus Fabricius, 1790 .

Despite many morphological differences, P. subdepressus can be confused with Tribolium spp ., closely related taxa ( Buchelos 1980; Mravinac et al. 2005) or, most commonly, with P. depressus (Fabricius, 1790) ( Halstead 1967) ( Fig. 3 C, D View FIGURE3 ). The main difference from the latter is the height of the genae ( Fig. 2 View FIGURE 2 ); P. depressus genae is slightly raised above the level of the clypeus, whereas P. subdepressus genae is more raised above the clypeus, with petaloid genae forming two small horns. The shape of the genae, i.e., forming an anterior part that is raised above and covers part of the eye, is continuous with the supraorbital carina.

The holotype of P. subdepressus was collected under camel dung from the Canary Islands in 1859 ( Champion 1896). The identification of this species in Egypt, in the storage rooms of Amarna, with Sithophilus granarius (Linnaeus, 1758) ( Dryophthoridae ) ( Panagiotakopulu 2001), and in the Spanish Sahara in 1943 ( Louveaux et al. 2022), supports its African origin. The species was probably introduced to Europe during the prehispanic period ( Henríquez-Valido et al. 2020). Excavations conducted at the Romano-British site of Alcester, Warwickshire, in 1964–1965 revealed the presence of P. subdepressus , indicating its introduction to England during the 3rd and 4th centuries AD ( Osborne 1971). However, Brendell (1975) mentioned that the species is not established in the UK, not knowing whether populations have survived, or the species reintroduced, but it is widespread mainly in the tropics ( Rees 2007).

Palorus subdepressus is a minor or secondary pest of stored products, mainly cereals; mycophagous ( Denux & Zagatti 2010). Consumes processed plant products ( Haines 1991), and those consumed previously by primary pests such as S. granarius which are also prey. The species can be found under bark, frequently in large numbers ( Halstead 1967).