Miridiba frontalis ( Fairmaire, 1886 )

Gao, Chuan-bu & Coca-Abia, María Milagro, 2021, Revision of the genus Miridiba Reitter, 1902 (Coleoptera, Scarabaeidae, Melolonthinae): genital morphotypes and new taxonomic data, European Journal of Taxonomy 749, pp. 1-94 : 26-28

Miridiba frontalis ( Fairmaire, 1886) (valid species)

Figs 34–36

Rhizotrogus frontalis Fairmaire, 1886: 325 (type loc.: Yunnan, China).

Miridiba frontalis – Keith 2005: 98 (combination).

Diagnosis

External morphology of adult ( Fig. 34 ). Body size 17–19.5 mm. Body surface with conspicuous pubescence on frons, basal part of elytra and pygidium. Clypeus shorter than frons, concave, with anterior edge emarginate at middle. Frontal carina well developed and sharp. Pronotum without pubescence on disc; anterior margin with short setae, without concavity at each lateral end; lateral margins smooth and glabrous, moderately sinuate at posterior half; anterior angles acute, not projected forward, elevated laterally; posterior angles obtuse. Prosternal process quadrangular-shaped. Scutellum glabrous, with punctures except lateral margins. Elytra with conspicuous pubescence on basal part, disc glabrous; epipleuron with pubescence except on apex. Foretibia with strong and sharp carina; insertion of inner spur closer third outer tooth than second one. Meso- and metatibia with transverse carina interrupted at middle, with a marked dorsal and ventral prominence; inner margin of dorsal surface with strong spines. Prepygidium regularly punctate, conspicuous short pubescence. Pygidium with punctures of irregular size and distribution; conspicuous pubescence on disc, longer toward apex; apical margin moderately widened and raised. Ventrites with conspicuous pubescence; ventrite 5 moderately depressed at posterior half, with pubescence longer on depressed part. Ventrite 6 flat, with diffuse punctures. Male genitalia. Parameres ( Fig. 35 ) with apices of dorsal branches moderately curveted; without pubescence or granules. Endophallus ( Fig. 36 ) with raspula of setae and spines larger toward distal end. Temones ( Fig. 36 ) with apophysis reduced and separated at distal end. Female unknown.

Material examined

Holotype

CHINA • ♂; “ Yunnan ”; “Museum Paris 1906 Coll. Lèon Fairmaire ”; “ Rhizotrog frontalis Fair Yunan ”; “ Type ”; “ Holotype Miridiba frontalis ( Fairmaire, 1886) CH. Bu Gao & M. Coca-Abia det. 2018”; “ Miridiba castanea (Wat.) Denis Keith det. 2003”; MNHN.

Other material

CHINA – Guizhou Prov. • 3 ♂♂, 1 ♀; Guiyang ; 6 Oct. 1979; C.-J. Yang leg.; C.-B. Gao det.; SYAU . – Hainan Prov. • 1 ♂; Hainan ; 1952; C.-B. Gao det.; SYAU . – Sichuan Prov. • 1 ♂; Xichang, Mt Lushan, Yuhuangdian ; 1700 m a.s.l.; 8 May 2005; J.-Y. Qiu leg.; C.-B. Gao det.; SYAU . – Yunnan Prov. • 3 ♂♂; Yunnan ; A. Davis leg.; Fairmaire det.; Coll. Fairmaire; MNHN • 2 ♂♂, 16 ♀♀; Kunming ; C.-W. Li leg.; Y.-W. Zhang det.; IZCAS • 3 ♂♂, 2 ♀♀; Shaotong ; 1981; C.-B. Gao det.; IZCAS .

Remarks

Keith (2005) transferred Rhizotrogus frontalis to Miridiba and synonymized it with M. castanea based on a series of male specimens labelled with the name of collector (Armand David). Indeed, Fairmaire (1886), in the introduction of the work in which he described R. frontalis , thanked Armand David for the Coleoptera specimens received, which could suggest that the types of R. frontalis are these specimens labelled with the name of that collector. However, Fairmaire (1886) indicated that the description of R. frontalis was based on only one specimen; therefore, the series studied by Keith (2005) cannot be syntypes. We have examined a male specimen of R. frontalis preserved in the collection of Léon Fairmaire (MNHN) labelled as a type and with an original label with his determination. Although Fairmaire (1886) thought that this unique specimen was a female judging from its short antennal club, it is actually a male. In fact, and contrary to other Rhizotrogini , the species of Miridiba do no show obvious sexual dimorphism in the antennal club, which is very short in both sexes. On the other hand, we agree with the transfer of R. frontalis to Miridiba , the features of the external morphology and genitalia show that this species belongs to this genus. Moreover, the antenna 9-segmented and parameres with two dorsal and two ventral branches separated from each other, allow us include it in morphotype I “ Trichophora ”. In contrast, we do not agree with the synonymy of Miridiba frontalis with M. castanea proposed by Keith (2005), who did not sufficiently justify this synonymy. We have compared the type of M. frontalis with those of M. castanea , finding them to differ by the following characters ( Table 2 ): head (pubescence on clypeus and frons, frontal carina), pronotum (anterior margin, anterior angles), the shape of the prosternal process, elytra (pubescence), foretibia (carina, inner spur), the protarsi and mesotarsi (tufts of setae), parameres (pubescence and granules at branches) and endophallus (internal structures). Accordingly, M. frontalis is established herein as valid species. The unique type specimen of M. frontalis ( Fairmaire, 1886) found in coll. Léon Fairmaire (MNHN) is a holotype by monotypy, and is labelled as holotype.

Distribution

China (Hainan, Guizhou, Sichuan, Yunnan).

Figures

Figs 34–36. Miridiba frontalis (Fairmaire, 1886), holotype (MNHN). 34. Habitus in dorsal view. 35. Parameres in dorsal (A), ventral (B) and lateral (C) views. 36. Endophallus (everted) and temones in dorsal view. Scale bars: 34 = 5.0 mm; 35–36 = 1.0 mm.