Cassida decussata Fabricius 1775
Creators: name: Sekerka, Lukáš
name: Barclay, Maxwell V. L.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Chrysomelidae
Cassida
Cassida decussata

description: Cassida decussata Fabricius, 1775
(Figs 19–21)
Cassida decussata Fabricius, 1775: 93.
Cassida venosa Fabricius, 1798: 84, syn. nov.
Type locality. Cassida decussata: ‘Jamaica’; C. venosa: ‘Cajennae’.
Type material examined. Cassida decussata: SYNTYPE: ♂, pinned, ‘? [hw] Type [w, p, round label with red frame] || venosa Fabr. [b, hw by C. H. Boheman] || Cassida. | decussata [hw] | Fab. [hw] | Type? C.J.G. [hw] [w, p, cb, hw by C. J. Gahan]’ (BMNH). Cassida venosa: SYNTYPE: pinned, ‘venosa [grey and hw by Fabricius pinned separately from the specimen]’ (JFUK).
Status in ZIMSEN (1964). P. 237; No. 4100 (no material listed).
Original description. ‘C. nigro coerulescens, elytris flavo maculatis: maculis dorsalibus reticulatis, lateralibus distinctis. Habitat in Jamaica. Mus. Brit.
Magna.Thoracis clypeus emarginatus, coerulescens, macula utrinque magna flava. Elytra dorso reticulata,margine maculis sex vel septem distinctis flavis.’ (FABRICIUS 1775).
Current status. Eugenysa decussata (Fabricius, 1775) stat. restit.
Remarks. FABRICIUS (1775) described this species from BMNH material only. ZIMSEN (1964) did not locate any material of this species, but stated that it was considered a synonym of Eugenysa grossa (Linnaeus, 1758), a synonymy established by SCHÖNHERR (1808). Searching in the BMNH collection we found a single specimen which agrees with the original description, having pronotum with two reddish spots and explanate margin of the elytra with seven more or less de¿ned red transverse spots. However, the specimen is conspeci¿c with E. venosa (Fabricius, 1798) not E. grossa as suggested by SCHÖNHERR (1808). The specimen was also studied by C. H. Boheman as it has his original handwritten identi¿cation label stating ‘ E. venosa’. However, Boheman apparently did not recognize the specimen as the Fabrician type. Charles Joseph Gahan, former BMNH Keeper of Entomology, labelled the specimen as a potential type around the turn of the 19 th century. There is no other specimen in the BMNH collection which agrees with the original description. Particularly characteristic is the pronotum with large red spots, a rare feature in this species. Therefore we agree with Gahan and consider the specimen as syntype because Fabricius did not state how many specimens he used for description. However, quite likely this was the only specimen he had.
Eugenysa grossa always has a red pronotum (at most with two indistinct black specks) thus it is evident even from the original description that C. decussata could not be the same as E. grossa.
The syntype has a weakly convex elytra (gibbous in E. grossa) and the explanate margin of the elytra ¿nely punctate (coarsely punctate in E. grossa). Because C. decussata is older name we restore its species status and place E. venosa as its junior synonym (the type in ZMUC has been seen).
The type locality of E. decussata is assumed to be erroneous as no species of Eugenysa is known from Antilles. The species is so far known only from French Guyana and Suriname.
description: Published as part of Sekerka, Lukáš & Barclay, Maxwell V. L., 2014, Fabrician types of Cassidinae (Coleoptera: Chrysomelidae) deposited in the Natural History Museum, London, pp. 657-684 in Acta Entomologica Musei Nationalis Pragae 54 (2) on pages 662-663, DOI: 10.5281/zenodo.5302244