Dinas (Microspina), Skuhrovec & Batelka, 2014

Skuhrovec, JiĜí & Batelka, Jan, 2014, Taxonomy of the Cape Verde endemic weevil genus Dinas (Coleoptera: Curculionidae: Entiminae). Part I: Description of a new subgenus, and two new species from São Nicolau Island, Acta Entomologica Musei Nationalis Pragae 54 (1), pp. 315-336 : 319-321

Microspina subgen. nov.

( Figs 2A, 2C, 2E, 2G , 3A–I , 7A–D )

Type species. Dinas sitonaeformis Wollaston, 1867: 137 .

Differential diagnosis. See in Table 1.

Etymology. The name of the new subgenus refers to the distinct spina at midlength of the femora and also represents the opposite to Macrospina Mateu, 1956 , the only Cape Verde endemic genus of longhorn beetles ( Cerambycidae ).

Comparative notes. We follow WOLLASTON (1867) and ROUDIER (1957) in recognizing two distinct groups of Dinas based on the adult morphological characters given above. In spite of that, we do not consider any of the diagnostic characters as adequate to delimit separate genera. Characters used for delimiting genera in the Entiminae (i.e. size and shape of the epistome, presence/absence of a carina separating the frons from the epistome, presence of the median longitudinal furrow on the epifrons, shape and length of the scrobe, shape of tibial apex, corbels and claws, position of sutures and ratio of length of abdominal ventrites) (R. Borovec, pers. comm.) are identical for all Dinas species. This is a reason why we assign the subgeneric rank to both groups recognized in this study.

Length of the scape and its ratio to the length of the funicle is sometimes used as a generic character (R. Borovec, pers. comm.). Species of Microspina subgen. nov. have a long scape, which overlaps the eyes distinctly more than in Dinas (s. str.) species. The length of the scape compared to the funicle, in Microspina subgen. nov. species, is identical (ratio = 1; ratio of scape vs. funicle and club together = 1.5); whereas Dinas (s. str.) species have a longer funicle than scape length (ratio = 0.85; ratio of scape vs. funicle and club together = 1.2). This difference may possibly be explained by the different life styles of the adults. Adults of Microspina subgen. nov. were observed on shrubs eating flowers and pollen grains. On the contrary, Dinas (s. str.) species have so far only been found on the ground and under stones, which may explain their shortened antennae, characteristic of ground-living Entiminae . Whether members of Dinas (s. str.) are nocturnal or diurnal is not known, but diurnal activity of Microspina species is of note, because Laparocerini in the Macaronesian region are nocturnal ( MACHADO & AGUIAR 2005) as are many other Entiminae (e.g. the majority of Otiorhynchus Germar, 1822 species ).

The Microspina subgen. nov. may be further subdivided into two subgroups. The characters de¿ning these subgroups are as follows: Microspina species from the Northern Chain islands have narrow elytra, elongated in males and much wider and more oval in females, and their rostrum is concave in the middle on the sides. On the contrary, Microspina species from the Southern Chain islands have broadly ovate elytra which only slightly differ in shape between males and females, and they have the rostrum parallel-sided in the middle.

Figures

Fig. 2. Differential diagnosis of the subgenera of Dinas: Dinas (Microspina) afonsoi sp. nov.:A – head, dorsal view; C – pronotum; G – elytra, dorsal view; Dinas (Microspina) sitonaeformis Wollaston, 1867: E – spina on profemora; Dinas (s. str.) strakai sp. nov.: B – variability of rostrum of Dinas (s. str.) strakai sp. nov., dorsal view; D – pronotum; F – spina on profemora; H – elytra, male, dorsal view.

Fig. 3. Dinas (Microspina) afonsoi sp. nov., holotype, male (A–B, E–F), female (G–I): A – habitus, dorsal view; B – elytra, lateral view; C – elytra of Dinas (Microspina) sitonaeformis Wollaston, 1867, lateral view; D – elytra of Dinas (Microspina) angusticeps Roudier, 1957, lateral view; E – aedeagus, dorsal and lateral view; F – spiculum gastrale; G – female sternite VIII; H – ovipositor; I – spermatheca. Scales: 1 mm, scale with ‘*’=2 mm, scale with ‘**’=0.5 mm.

Fig. 7. Habitats and biology of Dinas species: A–C – Dinas (Microspina) afonsoi sp. nov. on flowers of Euphorbia tuckeyana; D – Dinas sitonaeformis Wollaston, 1867 on twig of Periploca laevigata chevalieri in Chã de Caldeira; E – grassy slopes of Chã de Caldeira, São Nicolau with scattered Periploca laevigata chevalieri – locality of Dinas sitonaeformis. (Photos by Jakub Straka).