A review: A new subgeneric arrangement of the genus Chaetocnema Stephens (Chrysomelidae: Galerucinae: Alticini) with new subgenera based on spermathecal structures

Abstract :

Subgeneric classification of the genus Chaetocnema Stephens is reviewed. It is clear that the cosmopolitan genus needs a new subgeneric arrengement. As the preliminary studies we have done revealed the spermatecal morphology seems more appropriate and usable than external morphological characters in the subgeneric arrangements for many genera in Chrysomelidae family. The positive results obtained appear to be applicable also for the genus Chaetocnema and encouraged us to carry out this study. For this purpose, a new subgeneric arrengement of the Chaetocnema genus based on the known spermathecal structures of 83 Palaearctic, 59 Oriental, 37 Afrotropical, 19 Madagascan, 3 Nearctic and 8 Australian species is realized. Data were obtained and evaluated from the previous available studies that have been carried out for a long time and recently accelerated with revisional studiesTherefore, Palaearctic Chaetocnema species including Turkish species naturally were firstly evaluated and a total of 8 subgenera including nominative subgenus were identified for these species. Accordingly, except for the nominative subgenus, 5 new subgenera are desribed: C. (Confinoides) subgen. nov., C. (Hortensoides) subgen. nov., C. (Majoroides) subgen. nov., C. (Nigricoides) subgen. nov., C. (Pseudochaetocnema) subgen. nov. and the status of 2 old names are restored: C. (Plectroscelis) Dejean, 1836 stat. rest., C. (Udorpes) Motschulsky, 1845 stat. rest.These subgenera described, also for 59 Oriental species evaluated, were found available. On the contrary the Oriental, Madagascan and Nearctic species, the subgenera described were not found sufficient for all Afrotropical and Australian species and required the description of new subgenera too. Accordingly, 5 new subgenera are also desribed: C. (Biondiana) subgen. nov., C. (Dalessandroiana) subgen. nov., C. (Gahanioides) subgen. nov., C. (Longiconoides) subgen. nov., C. (Nitidoides) subgen. nov.According to the results of this study, a total of 4 subgenera were found to be common in each region evaluated. In addition, 2 subgenera occur only in Palaearctic region, while 4 subgenera present only in Afrotropical region and 1 subgenus occurs only in Australian region. With this study, all known Chaetocnema species in Palaearctic, Oriental, Madagascan and Nearctic regions, about 39% of all known Chaetocnema species in Afrotropical region and about 28% of all known Chaetocnema species in Australian region were evaluated. A key to the subgenera of the genus Chaetocnema Stephens on the basis of especially spermathecal morphology was also presented.

Keyword :

Chaetocnema, new subgenera, spermatheca, Alticini, Galerucinae, Chrysomelidae, Coleoptera, Palaearctic region, Oriental region, Afrotropical region, Madagascan region, Australian region

Author(s) : Özdikmen, H.
Downloads : 22
Published Issue : 2021 Vol. 16 Number 1

2021 Vol. 16 Number 1