Cistudinella inanis ( Boheman, 1854 )

Sekerka, Lukáš, 2016, Taxonomic and nomenclatural changes in Cassidinae (Coleoptera: Chrysomelidae), Acta Entomologica Musei Nationalis Pragae 56 (1), pp. 275-344 : 310-311

Cistudinella inanis ( Boheman, 1854)

Ischyrosonyx inanis Boheman, 1854: 324 (original description).

Cistudinella biguttata Hincks, 1956: 557 (original description), syn. nov.

Type localities. Ischyrosonyx inanis : ‘Brasilia’; Cistudinella biguttata : Brazil, Santa Catarina, Nova Teutonia.

Type material examined. Ischyrosonyx inanis : LECTOTYPE (designated by BOROWIEC 1999a): ♂, pinned, ‘ Brasil [w, p, s] || Bhn. [w, p, s] || LECTOTYPE | des. L. Borowiec [r, p, cb] || NHRS-JLKB | 000021011 [w, p, cb]’ ( NHRS).

Cistudinella biguttata : HOLOTYPE: ♀, pinned (right antennomere missing), ‘ Brasilien | Nova Teutonia | 27° 11’ B. 52° 23’ L | Fritz Plaumann | 7.II.[hw] 193[p]9[hw] [w, p, cb, bf; last row written vertically on left side] || TYPE [p] | Cistudinella | biguttata | Hincks [pi, hw by Hincks, cb] || Cistudinella | biguttata | Hincks TYPE. | Det.W.D.Hincks [w, hw by Hincks, cb]’ ( NHMB).

Remarks. HINCKS (1956) stated following: ‘This species [ Cistudinella biguttata ] is perhaps most closely allied to C. inanis with which it agrees in coloration and in having the caudal angles of the pronotum produced. The pronotum however is not so broad as in that species, the sinuation of the sides of the elytra is distinctly less marked, and the elytral puncturation is stronger. The surface is generally duller due to the presence of micro-sculpture.’

I had an opportunity to study types of both taxa as well as additional specimens in the Spaethʼs collection, which Hincks had at disposal and in my opinion all belong to a single species. The characters Hincks used to separate both taxa result from sexual dimorphism (width of the pronotum and lateral sinuation of the elytra) as males of Cistudinella generally have a much broader pronotum than females. The difference in punctation of elytra is matter of specimen preservation. The holotype of C. biguttata is perfectly preserved, with a fully hardened body, elytra not contaminated by fat and perfect colouration, resulting in the punctation being more obvious, including areolae and particularly micropunctation on intervals. In contrast, specimens of C. inanis from Spaeth collection are darkened due to fat accumulation or partial sclerotisation.As a result, the micropunctation on intervals is indistinct and punctures in striae look much finer. I therefore synonymize C. biguttata with C. inanis .

Distribution. Brazil: Santa Catarina ( HINCKS 1956).