Research Article 
Corresponding author: Eduard Petitpierre ( eduard.petitpierre@uib.es ) Academic editor: Natalia Golub
© 2016 Eduard Petitpierre.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Petitpierre E (2016) A chromosomal analysis of three species of Timarcha (Coleoptera, Chrysomelidae, Chrysomelinae). Comparative Cytogenetics 10(1): 2732. https://doi.org/10.3897/CompCytogen.v10i1.5570

The karyotypes of three species of Timarcha Latreille, 1829 have been analysed. T. (Metallotimarcha) metallica (Laicharting, 1781), has 18 + Xy_{p} male meioformula and 2n = 38 chromosomes, similar to those found in the two species of subgenus Americanotimarcha Jolivet, 1948, in agreement with morphological and molecular phylogenetic grounds. T. (Timarcha) carmelenae Petitpierre, 2013 displays 9 + Xy_{p} and 2n = 20 chromosomes as in morphologically related Andalusian species, whereas T. (Timarcha) parvicollis ssp. seidlitzi Kraatz, 1879 shows 11 + Xyp and 2n = 24 chromosomes, clearly differing from the previous species. These results are discussed in order to get an insight into the main trends of the chromosomal evolution in Timarcha.
Coleoptera , Chrysomelidae , Chrysomelinae , karyotypes, Timarcha , evolution
The highly speciose genus Timarcha Latreille, 1829 comprises more than three hundred described taxa, almost all from the Palaearctic (
Herein, we report the chromosome numbers, male sexchromosome systems, and main features of their karyotypes of T. (Metallotimarcha) metallica (Laicharting, 1781), T. (Timarcha) carmelenae Petitpierre, 2013 and T. (Timarcha) parvicollis ssp. seidlitzi Kraatz, 1879 to enlarge the cytogenetic analysis of the genus and discuss the most relevant trends of its chromosomal evolution.
The three checked species and their geographical origins are given in Table
Chromosomally analysed species of Timarcha and their geographical sources. FR=France, SP=Spain.
T. metallica (Laicharting, 1781)  Deville: Bois de Waibes, Ardennes (FR) 
T. carmelenae Petitpierre, 2013  P.N. Sierra de Castril: Sierra Seca, Granada (SP) 
‘’ La Sagra: collado de las Víboras, Granada (SP)  
T. parvicollis seidlitzi Kraatz, 1879  Sierra Tejeda: La Maroma, Granada (SP) 
Two males of this species have displayed 2n= 38 chromosomes and an 18 + Xy_{p} male meioformula, with a “parachute” Xy_{p} sexchromosome system (Fig.
1–3 T. metallica: 1 spermatogonial mitotic metaphase with 2n = 38 chromosomes, the ychromosome is arrowed 2 meiotic metaphase I with 18 + Xy_{p} meioformula, the Xy_{p} is arrowed 3 meiotic metaphase II with n = 19 chromosomes 4–5 T. carmelenae: meiotic metaphases I from Sierra de Castril (4) and La Sagra (5) individuals, with 9 + Xy_{p} meioformula, the Xy_{p} are arrowed 6T. parvicollis ssp. seidlitzi: meiotic metaphase I with 11 + Xy_{p} meioformula, the Xy_{p} is arrowed and two partly overlapped autosomal bivalents are arrowheaded. Bar: 5 µm.
One male individual from Sierra Seca and another from La Sagra provided meiotic metaphases I of 9 + Xy_{p}, again with a “parachute” Xy_{p} sexchromosome system, that is 2n = 20(Xy_{p}) chromosomes, and showing two autosomal bivalents a bit larger than the others (Figs
The only checked male individual provided meiotic metaphase I with an 11 + Xy_{p} meioformula, having also a “parachute” Xy_{p} sexchromosome system, thus 2n = 24(Xy_{p}), where five autosomal bivalents are larger than the remaining six ones (Fig.
The diploid number of 2n = 38 chromosomes shown in Timarcha (Metallotimarcha) metallica should correct a previous miscounting report of 2n = 20 chromosomes (
The karyotype of T. (T.) carmelenae with 2n = 20(Xy_{p}), with two larger autosomal bivalents and the remaining gradually decreasing, is similar to those of T. (T.) intermedia HerrichSchäffer, 1838, and T. (T.) lugens Rosenhauer, 1856 (
T. (T.) parvicollis ssp. seidlitzi shows a karyotype of 11 + Xy_{p} male meioformula, thus 2n = 24(Xy_{p}) chromosomes, which separates it strikingly from the related Andalusian species with 2n = 20(Xy_{p}) such as T. (T.) insparsa Rosenhauer, 1856, T. (T.) marginicollis Rosenhauer, 1856, T. (T.) intermedia, T. (T.) lugens Rosenhauer, 1856 and T. (T.) carmelenae, sharing a bifid mesosternum and elytra covered with spare and fine puncturation.
Another species of Timarcha with 2n = 24 chromosomes, T. (T.) pratensis (Duftschmid, 1825) (
I am very much indebted to Mr. Alain Grafteaux (CharlevilleMézières, France) for sending the sample of T. metallica and to Dr. José Antonio JuradoRivera (Palma de Mallorca, Spain), who helped me in collecting the specimen of T. parvicollis ssp. seidlitzi and by arranging and improving the micrographs.