Zootaxa 2359: 65–67 (2010) www.mapress.com / zootaxa/ ISSN 1175-5326 (print edition) Correspondence Copyright © 2010 · Magnolia Press ZOOTAXA ISSN 1175-5334 (online edition) The karyotype of Chironomus acerbiphilus Tokunaga, 1939 (Diptera: Chironomidae) from Poland IZABELA JABLONSKA-BARNA1, 5, PARASKEVA MICHAILOVA2, ANDRZEJ KOWNACKI3 & PETER H. LANGTON 4 1 Department of Applied Ecology, Faculty of Environmental Sciences and Fisheries, University of Warmia and Mazury in Olsztyn, ul. M. Oczapowskiego 5, 10-719 Olsztyn, Poland 2 Institute of Zoology, Bulgarian Academy of Sciences, 1 Tzar Osvoboditel boulv. 1000 Sofia, Bulgaria 3 Karol Starmach Department of Freshwater Biology, Institute of Nature Conservation, Polish Academy of Sciences, al. A. Mickiewicza 33, 31-120 Kraków, Poland 4 University Museum of Zoology, Downing Street, Cambridge, UK (Address for correspondence: 5 Kylebeg Avenue, Mountsandel, Coleraine, N. Ireland BT52 1JN) 5 Corresponding author: e-mail: ijpb@uwm.edu.pl The chromosome set of Chironomus crassimanus Strenzke, 1959 and pictures of its salivary gland chromosomes were presented by Keyl and Keyl (1959) and Keyl (1962). Keyl (1962) described the band sequence of chromosome AE compared with that of other Chironomus species. Later, Michailova (1989) described the chromosome markers of this species using material from Bulgaria. Martin (2006) indicated that the banding patterns of arms A and E of Chironomus acerbiphilus Tokunaga, 1939 are as in C. crassimanus and consequently suggested synonymy. Our study presents the karyotype of Chironomus acerbiphilus (= C. crassimanus) from Poland. This species is new for the Polish fauna. The material was collected from an acid strip-mine lake (pH = 3) located in the Łuk Mużakowa Landscape Park (western Poland; 51o 45’N, 14 o 46’E) . The chemical properties of the water were presented by Ję drczak (1992). Chironomid larvae were sampled from Lake No 54 which has an area of 20.2 ha and a maximum depth of 24 m. Fourteen specimens of IVth larval stage were analyzed cytotaxonomically. The salivary gland chromosomes were prepared according to Michailova (1989). The standardization of banding pattern in arms A, E and F follows Keyl (1962) and arm CD - Devai et al. (1989). The comparison of the band sequence of chromosome CD was done with Chironomus piger Strenzke, 1959. The band sequences of chromosome arms A, E, F, C and D are given in detail as a chromosome map. The karyotype of Chironomus acerbiphilus 2n = 8, with chromosome arm combinations AE, BF, CD, and G. The species belongs to the “pseudothummi cytocomplex”. The centromere regions of the chromosomes are expressed by large heterochromatin blocks, which are often conjugated. Chromosomes AE and CD are submetacentric, BF - metacentric and G - telocentric. One Balbiani ring (BR) is in chromosome G, a Nucleolar Organizer (NOR) is in chromosome AE. Arm A (Fig. 1 a) has the following band sequence:1a-i-7-9-2d-k-3-12-10-2c-a-1k-6-5-4-13-14-15-16-19. The fixed homozygous inversion in section 7-1k distinguishes it from Chironomus holomelas Str. The band sequence 5 - 4-13-1415-16-19 is the same in both species. The band sequence 2d-3, 12-10, 13-19 is very similar to that of Chironomus pseudothummi Strenzke, 1959 (Keyl 1962). The Nucleolar Organizer (NOR) is located in section 13-15. Arm E (Fig. 1 a) has the band sequence:1-2-3-ae-10b-3f-10cg-13-11. It is the same as the band sequence of this arm of Chironomus acidophilus Keyl, 1960 (Keyl 1960), C. aprilinus Meigen, 1818 and C. uliginosus Keyl, 1960 (Keyl 1962) as well as of C. frommeri established by Atchley and Martin (1971) and C. whitseli analyzed by Sublette and Sublette (1974). Arm F (Fig. 1 b) has the band sequence: 1-7-17-16-11-12-13-14-15-14b- 4 -5-6-9-8-1-2-3-10-18-19-20. It differs from that of Chironomus uliginosus by several inversion steps (the underlined sections are the sections involved in the inversions involved in different steps of the formation of the karyotype): Chironomus uliginosus: 1-7-6-5-4-14b-15-10-3-2-1-8-9-14-13-12-11-16-17-18-19-20 Accepted by W. Gilka: 5 Jan. 2010; published: 15 Feb. 2010 65 1-7-17-16-11-12-13-14-6-5-4-14b-15-10-3-2-1-8-9-18-19-20 1-7-17-16-11-12-13-14-6-5-4-14b-15-9-8-1-2-3-10-18-19-20 Chironomus acerbiphilus: 1-7-17-16-11-12-13-14-15-14b-4-5-6-9-8-1-2-3-10-18-19-20 The band sequence 18-20 is the same as that of Chironomus aprilinus and C. holomelas (Keyl 1962). In Chironomus uliginosus there is an active area in section 11 (Keyl 1962), which in the studied species has been transferred to the beginning of the chromosome arm F. FIGURE 1. Salivary gland chromosomes of Chironomus acerbiphilus. a—AE chromosome, b—FB chromosome, c— CD chromosome, d—G chromosome, NOR—nucleolar organizer, P-puff, BR—Balbiani ring, arrow —centromere region. 66 · Zootaxa 2359 © 2010 Magnolia Press JABLONSKA-BARNA ET AL. Arm B (Fig. 1 b). Due to bad structure it is not possible to map the band sequences of this arm. Some bands in sections 1, 2 are basic for this arm (Wülker 1980). Arm C ( Fig. 1 c). It differs from that of Chironomus piger by a one step fixed homozygous inversion. Chironomus piger: 1-2-3-4-5-6-7-8-9abcd-10-11-12-13-14-15-16-17-18-19-20-22 Chironomus acerbiphilus: 1-2-10-9dcba-8-7-6-5-4-3-11-12-13-14-15-16-22- 24-21. (The section from 24 to 21 is transferred from arm D as has been established by Wülker (Martin 2006). The basic pattern of the arm (sections 11-12) is located almost in the middle of the arm. Arm D (Fig. 1 c).The band sequence of this arm differs from that of Chironomus piger by several homozygous inversions. Chironomus piger: 1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18afg-19-24 1-2-3-4-5-6-7-8-9-18fa-17-16-15-14-13-12-11-10-18g-19-24 1-2-3-6-5-4-7-8-9-18fa-17-16-15-14-13-12-11-10-18g-19-24 1-2-3-6-5-4-7-8-9-18fa-10-11-12-13-14-15-16-17-18g-19-24 1-2-3-6-5-4-7-8-9-18fa-13-12-11-10-14-15-16-17-18g-19-24 Chironomus acerbiphilus:1-2-3-6-5-4-7-8-9-18fa-13-12-11-10-17-16-15-14-18g-19-20. The band sequence in section 21-24 is transferred to arm C as has been found by Wülker (Martin 2006). The basic pattern of the arm is located in the middle of the arm (3). Arm G (Fig. 1 d).The Balbiani ring (BR) is located in the middle of the arm. The homologues are always conjugated. Acknowledgements This study was supported through a grant of the Bulgarian Ministry of Education and Sciences (grant B1601) as well as through the Exchange Research Program between Bulgarian and Polish Academy of Sciences. References Atchley, W.R. & Martin, J. (1971) A morphometric analysis of differential sexual dimorphism in larvae of Chironomus (Diptera). The Canadian Entomologist, 103, 319–327. Devai, Gy., Miscilczi, M. & Wülker, W. (1989) Standarization of chromosome arms B, C and D in Chironomus (Diptera, Chironomidae). Acta Biologica Debrecina, Supplementum Oecologica Hungarica 2, 79–92. Jędrczak, A. (1992) Chemical composition of anthropogenic lakeland in Luk Muzakowa. Wydawnictwo Wyższej Szkoły Inżynierskiej w Zielonej Górze, 139 pp. [in Polish] Keyl, H. (1960) Die cytologische Diagnostik der Chironomiden. II. Diagnosen der Geschwisterarten Chironomus acidophilus n. sp. und Ch. uliginosus n. sp. Archiv für Hydrobiologie, 57, 187–195. Keyl, H. (1962) Chromosomenevolution bei Chironomus. II. Chromosomenumbauten und phylogenetische Beziehungen der Arten. Chromosoma, 13, 464–514. Keyl, H. & Keyl, I. (1959) Die cytologische Diagnostik der Chironomiden. Bestimungstabelle fur die Gattung Chironomus auf Grind der Speicheldrusen-chromosomen. Archiv für Hydrobiologie, 56, 43–57. Martin, J. (2006). North American Cytospecies of the genus Chironomus (includes Camptochironomus, Chaetolabis and Einfeldia). Available from: http://www.genetics.unimelb.edu.au/Martin/NACytfiles/NACytospecies07.pdf (accessed: 12th Dec. 2008) Michailova, P. (1989) The polytene chromosomes and their significance to the systematics of the family Chironomidae, Diptera. Acta Zooogica Fennica, 186, 1–107. Sublette, J.E. & Sublette, M.F. (1974) A review of the genus Chironomus (Diptera, Chironomidae) V. The maturuscomplex. Studies of Natural Sciences, Portales, New Mexico, 1(8), 1–41. Wülker, W. (1980) Basic patterns in the chromosome evolution of the genus Chironomus (Diptera). Zeitschrift für zoologische Systematik und Evolutionsforschung, 2, 112–123. THE KARYOTYPE OF CHIRONOMUS ACERBIPHILUS Zootaxa 2359 © 2010 Magnolia Press · 67