Machleida Fahraeus , 1870

Kaminski, Marcin J., Kanda, Kojun & Smith, Aaron D., 2019, Taxonomic revision of the genus Machleida Fahraeus, 1870 (Tenebrionidae, Pimeliinae, Asidini), ZooKeys 898, pp. 83-102 : 83

Genus Machleida Fahraeus, 1870

Machleida Fahraeus, 1870: 256

= Machloida Rye, 1873: 286. Type species: Machleida nodulosa Fåhraeus, 1870, by monotypy. Note. Unjustified emendation of Machleida Fåhraeus, 1870, not in prevailing usage.

Type species.

Machleida nodulosa Fåhraeus, 1870; by monotypy.

Revised diagnosis.

Exclusion of Asida lecta Peringuey, 1899, Machleida nossibiana Fairmaire, 1897, and Machleida tuberosa Wilke, 1925 (see below) from Machleida increased the morphological consistency of the genus. As a result, some of the previously listed diagnostic characters needed to be revised (e.g., sculpture of pronotum). Additionally, the present investigation reveals that some of the characters proposed by Koch (1962) are too variable within Afrotropical Asidini to be sustained as diagnostic for Machleida . A revised diagnosis is presented below.

The representatives of this genus can be distinguished from other Afrotropical Asidini by the following combination of characters: antenna appearing as 10-segmented, with antennomeres 10 and 11 of equal in width ( Fig. 1D ); mentum reduced basally, not fully filling buccal cavity ( Fig. 1C ); pronotal disc with large primary sculpturing consisting of two median carinae merged in the middle ( Fig. 1B ), carinae not merging in M. zofiae Kamiński sp. nov. ( Fig. 1A ); hypomeron with shallow, posteriorly abbreviated antennal sulcus; elytra with large tubercles ( Fig. 2 ); and expanded epipleura (sometimes fully fused with the neighbouring part of elytra) ( Fig. 3A, B ). Moreover, all Machleida species shares a peculiar structure of mesoprescutum, i.e. base deeply emarginate ( Fig. 3C ).

Species composition (6).

M. banachi sp. nov.; devia ( Péringuey, 1899); flagstaffensis sp. nov.; nodulosa Fåhraeus, 1870; tarskii sp. nov.; zofiae Kamiński sp. nov.

Excluded species ( lecta , nossibiana , tuberosa ).

These species are hereby excluded from Machleida based on differences in the structure of the mentum (fully filling buccal cavity), prosternal process (base straight in lateral view, process not convex), and pronotum (disc only basally with median carinae, lateral tubercles absent). Asida lecta Péringuey, 1899 does not fall within the newly formulated concept of Machleida . The aforementioned pronotal structure place this species within the subgenus Archasida Wilke 1922 of Afrasida Wilke, 1925 ( Koch 1962). As a result, the following new combination is proposed: Afrasida ( Archasida ) lecta ( Péringuey, 1899) comb. nov. A habitus photo of this species is presented in Appendix 2: Fig. S1A.

Because of its Malagasy distribution, the taxonomic placement of M. nossibiana Fairmaire, 1897 within the South African Machleida was previously questioned by several authors ( Chatanay 1914; Wilke 1925; Gebien 1937). However, based on a single non-typical specimen, Koch (1962) tried to provide some morphological support for this taxonomic hypothesis. According to his view M. nossibiana generally resembles species of Machleida and can be separated from other Malagasy Asidini by the non-soleate underside of the tarsi. In his diagnosis he compared this species to M. nodulosa and highlighted two main morphological differences: antennae robust in M. nossibiana , slender in M. nodulosa ; and prosternal process broad in M. nossibiana , narrow in M. nodulosa . The current reinvestigation of the type material of M. nossibiana (Appendix 2: Fig. S1B) revealed a high morphological resemblance of this species to representatives of the genus Scotinesthes Fairmaire, 1895 ( Koch 1962). Namely, the aforementioned characters used by Koch to separate M. nossibiana from M. nodulosa are characteristic for Scotinesthes . Moreover, M. nossibiana shares a common structure of the mentum (fully filling buccal cavity; reduced basally in Machleida ) with the other species representing that Malagasy genus. As a result, nossibiana is transferred from Machleida and the following new combination is introduced: Scotinesthes nossibianus (Fairmaire, 1897) comb. nov.

Reinvestigation of the type material revealed that Machleida tuberosa Wilke, 1925 has a peculiar pronotal sculpturing, i.e., disc without carinae but densely covered with small setose tubercles (Appendix 2: Fig. S1C). The second character seems to be unique for this species among the other southern African Asidini . Because of the aforementioned features, M. tuberosa does not fit the newly proposed taxonomic concept of Machleida and is hereby excluded from this genus. The exact placement of this species (possibly a new genus) requires further investigation in a wider taxonomic context. At the moment tuberosa is treated as incertae sedis Asidini .

Distribution.

Representatives of this genus have been collected in the following ecoregions of South Africa ( Fig. 5 ): Drakensberg Montane Woodlands and Grasslands, KwaZulu-Cape coastal forest mosaic, Maputaland-Pondoland bushland, and thickets, Southern Africa mangroves.

Figures

Figure 1. Selected diagnostic characters proposed for Machleida and its species. A, B Pronotal disc with specific surface modifications C ventral aspect of postoral regions D antenna E, F dorsal aspect of head. Illustrated species: A, D Machleida zofiae B M. nodulosa C M. tarskii E M. devia F M. flagstaffensis.

Figure 2. Habitus images of the studied species. A Machleida banachi B M. devia C M. flagstaffensis D M. nodulosa E M. tarskii F M. zofiae.

Figure 3. Morphological details of selected Machleida species. A, B Lateral aspect of elytron C scutellum and D, E elytral disc. Illustrated species: A Machleida tarskii B M. banachi C M. zofiae D M. devia E M. nodulosa.

Figure 5. Distribution of species of the genus Machleida.