Phylogenetic systematics of the gondwanan Empis macrorrhyncha group (Diptera,Empididae, Empidinae)

The Empis macrorrhyncha group (Diptera: Empididae) from cool to warm temperate areas of South America and Australia is diagnosed and cladistically analysed, and five new species, Empis animosa sp.n. , E. austera sp.n. , E. maculosa sp.n. , E. occidentalis sp.n. and E. pedivillosula sp.n. , are described. Cladistic analysis of 23 adult morphological characters for 14 species of the group generated a single tree of 28 steps (CI = 0.82; RI = 0.93). Monophyly was established on the basis of a single apomorphy, possession of a bilobed cercus of the male hypopygium. Three main clades were inferred: clade 1 included three Patagonian and a single southwestern Australian species; clade 2 included two species from southeastern Australia; clade 3 included a large Patagonian group of five species and a single southeastern Australian species. The E. fulvicollis complex (clade 1) is a sister‐group of the E. macrorrhyncha complex (clades 2 + 3). A provisional historical biogeographic hypothesis is advanced correlating the appearance of the South American and Australian sister lineages with the timing of the break‐up of Gondwana.     

Chromosomes of Syrphidae

This report describes the karyotypes of five species of the tribe Sericomyiini (Diptera, Syrphidae). The five species are: Sericomyia chalcopyga Lw. (2n=12), S. chrysotoxoides Mq. (2n=10), S. lata (Coq.) (2n = 12), S. militaris Walker (2n=12) and S. sp. 1 (2n=10). Polytene chromosomes of Arctophila flagrans O. S. are illustrated.Dedicated to Prof. J. Seiler on the occasion of his 80th birthday.     

Taxonomic implications of genome size for all species of the genus Gasteria Duval (Aloaceae)

Nuclear DNA content (2C) is used as a new criterion to investigate all species of the genus Gasteria Duval including the three recently described species Gasteria polita van Jaarsv., G. pendulifolia van Jaarsv. and G. glauca van Jaarsv.. The 122 accessions investigated have the same chromosome number (2n=2x=14), with exception of three tetraploid plants found. The nuclear DNA content of the diploids, as measured by flow cytometry with Propidium Iodide, is demonstrated to range from 32.8–43.2 pg. This implies that the largest genome contains roughly 10¹⁰ more base pairs than the smallest. Based on DNA content the species could be divided in five groups: G. rawlinsonii Oberm. with 32.8 pg, 13 mostly inland species with 34.3–36.0 pg, five coastal species with 36.5–39.0 pg and Gasteria batesiana Rowley with 43.2 pg. The thirteen species with 34.3–36.0 pg could be divided further, in a group of eight species occupying mainly very restricted areas with 34.3–35.1 pg and a second group of five species with 35.2–36.0 pg mainly occupying large areas. These five groups did not coincide very well with the two sections and four series of Gasteria based on a cladistic analysis by van Jaarsveld et al. (1994). Based on its long leafy branches, location in the centre of Gasteria species distribution and its by far lowest DNA content, G. rawlinsonii might be the most primitive member of the genus. Nuclear DNA content as measured by flow cytometry is shown to be relevant to provide additional information on the relationships between Gasteria species.     

风毛菊属5种植物的核型分析

采用常规压片法,对风毛菊属(Saussurea)5种植物的染色体数目和核型类型进行分析。结果表明:大耳叶风毛菊(S.macrota)核型公式为2n=2x=26=10m+12sm+4st,属2A型;长梗风毛菊(S.dolichopoda)核型公式为2n=2x=26=14m+8sm+4st,属2A型;川陕风毛菊(S.licentiana)核型公式为2n=2x=28=12m+16sm,属2B型;杨叶风毛菊(S.populifolia)核型公式为2n=2x=28=6m+18sm+4st,属2B型;尾叶风毛菊(S.caudata)核型公式为2n=2x=30=14m+14sm+2st,属2A型。这5种风毛菊属植物中,除大耳叶风毛菊染色体数目和核型类型与前人报道的一致外,其余4种植物的染色体数目和核型类型均为首次报道,并在川陕风毛菊中发现1对B染色体。     

Karyological studies of five species of land snails (Helicoidea: Mollusca)

The karyotypes of five species of Helicoidea (Japanese land snails) were analyzed by the air-drying method, using embryonic cells. Somatic cells of Satsuma omphalodes and S. japonica had 2n=58. Karyotypes of Acusta despecta sieboldiana (2n=58), Euhadra dixoni and E. amaliae (2n=56) were also analyzed. Chromosomes of these five species are all metacentric or submetacentric. Two species of Euhadra, dixoni and amaliae, have identical karyotypes while karyotypes of S. omphalodes and S. japonica indicate some dissimilarity in medium-sized and small-sized chromosomes. On the basis of karyotypical characters, A. d. sieboldiana was recognized to be closely related to the Satsuma species, which belong to a different family rather than to Euhadra of the same family as Acusta.     

Karyology of Aconitum subgenus Lycoctonum (Ranunculaceae) from China,with a report of the new base chromosome number x = 6 in the genus Aconitum

In order to gain better knowledge of the number and morphology of chromosomes in Aconitum subgen. Lycoctonum in China, 60 populations belonging to 20 species were cytologically studied. Chromosome numbers of six species (A. apetalum, A. finetianum, A. fletcheranum, A. longecassidatum, A. umbrosum and A. wangyedianense) are here reported for the first time. One species, A. fletcheranum, has 2n = 12, and thus is a diploid based on x = 6, a new base chromosome number for the genus Aconitum. Most of the remaining taxa are diploid (2n = 16) based on x = 8, but five taxa (A. angustius, A. brevicalcaratum var. brevicalcaratum, A. brevicalcaratum var. parviflorum, A.chrysotrichum and A. crassiflorum) are tetraploid with 2n = 32, and one species (A. apetalum) is hexaploid with 2n = 48, the highest ploidy level currently known in the subgenus. Disregarding differences in the presence or absence and number of satellites, the karyotypes of all the 2n = 16 species are quite uniform (2n = 2m + 6sm + 8st), but A. novoluridum, the only species of A. section Alatospermum, has an intrachromosomally less asymmetric karyotype (2n = 2m + 14sm), which lends further support for the primitive condition of its section as inferred from gross‐morphology. Chromosomal variation in the subgenus and the relationships of some of the species are discussed.     

New insights on systematics and phylogenetics of Mediterranean Blaps species (Coleoptera: Tenebrionidae: Blaptini), assessed through morphology and dense taxon sampling

The genus Blaps is an emblematic group of large flightless beetles adapted to semi‐arid and arid environments. About 230 species have been described in the subgenus Blaps, which is the largest of the four extant subgenera. Within this subgenus, one large group of morphologically homogeneous species is of particular interest, and comprises the species formerly assigned to Seidlitz's division one. Strikingly, almost all species in this group are endemic to the Mediterranean basin, whereas the remaining Blaps species are mostly distributed in Asia. Here we present the first phylogenetic hypothesis for the Mediterranean Blaps and several taxonomic clarifications for the North African species belonging to this group. Based on careful examination of almost all type material and thousands of specimens for all known species and subspecies (initially 65 taxa), seven lectotypes are designated and six new synonymies are established: Blaps heydeni Allard, 1880 = Blaps heydenissp. taciturna Peyerimhoff syn.n. , Blaps emondi Solier = Blaps nitidula Solier syn.n. , Blaps tripolitanica Karsch = Blaps vialattei Peyerimhoff syn.n. , Blaps bifurcata strauchi Reiche = Blaps bifurcata ssp. gridellii Pierre syn.n. , Blaps cognata Solier = Blaps schweinfurhtii Seidlitz syn.n. and Blaps judaeorum Miller = Blaps pharao Seidlitz syn.n. Among the examined material, five species are also new for science and are assigned to extant species group. To infer species relationships, a morphological character matrix was assembled and analysed using both parsimony and probabilistic methods. All analyses yielded a similar and repeatable phylogenetic pattern, which allows us to discuss the systematics of the Mediterranean endemic species, the limit of extant species groups and to clarify the taxonomic status of several ambiguous taxa. We also reveal the existence of a large clade that encompasses the eastern Mediterranean species that are also mostly associated with arid regions. This clade is embedded within a second group that corresponds to western Mediterranean species, which are generally found in semi‐arid regions. Finally, we discuss the relevance of species groups in relation to their geographic distribution. This work represents a first step for further studies in taxonomy, systematics and historical biogeography of Blaps species.     

Genetic divergence in Northamerican freshwater planarians of the Dugesia dorotocephala group (Turbellaria, Tricladida, Paludicola)

The genetic differentiation between the members of the Dugesia (Girardia) dorotocephala group was analyzed by means of multilocus electrophoresis, and comared to that of another planarian secies, D. tahitiensis, also belonging to the subgenus Girardia. The species examined were: D. dorotocephala s.s (2n = 16), D. arizonensis (2n = 8), D. jenkinsae (2n = 8), and the above mentioned D. tahitiensis (2n = 16). The former three species inhabit North America, and show different proportion of fissiparous and sexual individuals; the latter species inhabits Polynesia and is fully asexual. A total of 11 enzyme loci were genetically analyzed: Mdh-1, Mdh-2, Zdh-1, Idh-2, G3pdh, Got-1, Ck, Pgm-2, Ada, Mpi, and Gpi. Low values of observed mean heterozygosity per locus (Ho) were found in the populations studied, ranging from 0 to 0.18 (average 0.08. In asexual populations (except that of D. tahitiensis) fixed heterozygosity was observered in all the individuals for 1 or 2 loci. The genetic divergence between the species examined is very high, with many loci showing discriminating alleles in different taxa (Nei's genetic distance varies from 0.871 to 1.759). The populations of D. dorotocehala s.s., on the contrary, appear to be genetically quite homogenous average D= 0.019), and the genetic distance values are apparently unrelated to their geographic location and to their way of reproduction. The genetic distance between D. tahitiensis, a species not included in the D. dorotocephala group and D. dorotocephala s.s. is 1.314 and hence similar to the D value between two members of;he dorotocephala group: D. dorotocephala and D. jenkinsae (D = 1.303). The genetic relationships among the populations studied were established by UPGMA cluster analysis and multidimensional scaling. The descendence of the North American species with 2n = 8 from a dorotocephala-like ancestor with 2n = 16 is considered. It is suggested that the latter, as well as a tahitiensis-like line, also having 2n = 16, have originated from a common ancestor by geographic isolation.     

Chromosomal features and evolution of Bromeliaceae

New cytological information and chromosome counts are presented for 19 taxa of 15 genera of the Bromeliaceae, among them, data for 15 taxa and five genera are reported for the first time. The basic number x = 25 is confirmed and polyploidy seems to be the main evolutionary mechanism in Bromeliaceae. Most of the analyzed species presented 2n = 50. Polyploids have been detected in Deinacanthon urbanianum with 2n = ca.160 and Bromelia laciniosa with 2n = ca.150. In Deuterocohnia lorentziana we observed individuals with two different ploidy levels (2n = 50 and 2n = 100) growing together in the same pot. Ayensua uaipanensis showed the uncommon number 2n = 46. After triple staining with CMA₃/Actinomycin/DAPI one or two CMA⁺/DAPI⁻ bands could be observed in the studied species (Aechmea bromeliifolia, Greigia sphacelata and Ochagavia litoralis). The role of these features in the evolution of the family is discussed, revealing new aspects of the evolution of the Bromeliaceae.     

Artificial and natural hybrids in pycnanthemum (Labiatae)

Further chromosome counts, principally from the southeastern United States, are reported for 38 accessions of 11 species, together with new or corrected counts forP. nudum (2n = 40),P. montanum (2n = 40),P. curvipes (2n = 40), andP. torrei (2n = 80). Four species have now been shown to have intraspecific polyploidy, five are known only as diploids, and nine occur only at the tetraploid level. Artificially produced interspecific hybrids range from vigorous to dwarfed or nonflowering, and from semifertile to sterile as measured by anther development and stainable pollen. Naturally occurring hybrids are described for the following species combinations:P. clinopodioides ×P. incanum,P. pilosum ×P. virginianum, P. flexuosum ×P. nudum, andP. albescens ×P. loomisii.

     

Chromosomal evolution of the Hawaiian Telmatogeton (Chironomidae,Diptera)

It is only in the Hawaiian Islands that species of the otherwise marine genus Telmatogeton have evolved into freshwater. An analysis of polytene chromosomes and karyotypes of two marine species and five freshwater species revealed that paracentric inversions and centric fusions were important in chromosomal evolution. The sequence of polytene chromosome bands common to most species, established as the Telmatogeton standard sequence, is found in a population of T. torrenticola from West Maui. Most species and other populations of T. torrenticola may be derived from the standard sequence by paracentric inversions. Similarities with the standard band sequence places T. japonicus (n=7) rather than T. pacificus (n=4) in the proposed phylogeny as the species closest to the marine ancestor of the freshwater species. One of three species (T. fluviatilis from Oahu, T. torrenticola from West Maui, or an undescribed species from East Maui), each with seven pairs of chromosomes is considered to be closest to the original freshwater species. T. torrenticola is a complex species in which there is an accumulation of fixed inversions and centric fusions in stepwise fashion in populations from west to east (West Maui n=7; East Maui n=6; Kohala Mountains n=5 and Mauna Kea n=4 both from the island of Hawaii). The population of T. torrenticola from Molokai has a reduced chromosome number (n=4) and fixed inversions. T. abnormis and T. hirtus, the only species which exhibit differentiated sex chromosomes, may be derived from the standard sequency by paracentric inversions. T. abnormis (n=4) has a simple XY system and T. hirtus (n=3/4) has a complex XY₁Y₂ system. Unique sequences of bands, differences in staining intensity of puffs and bands, and an inversion form the basis for the differentiation of the various Y-chromosomes in these species.     

青藏高原5种石竹科垫状植物的核型研究

垫状植物是高山冰缘带植物区系的重要组成成分,是植物适应高寒环境趋同进化的特殊生活型。该研究以采自西藏和云南高山冰缘带的5种石竹科垫状植物种子为材料,采用滤纸萌发法、常规压片法镜检观察分析其核型,为青藏高原垫状植物积累核型资料,并为探讨极端环境下特殊生活型植物的核型进化机制提供依据。结果表明:5种植物均为二倍体,染色体核型分别为:密生福禄草(Arenaria densissima),2n=2x=20m+2sm,2A;山生福禄草(A.oreophila),2n=2x=22m,1A;团状福禄草(A.polytrichoides),2n=2x=20m+2sm,2A;大花福禄草(A.smithiana),2n=2x=20m+2sm,1A;囊种草(Thylacospermum caespitosum),2n=2x=18m+4sm,2A。囊种草与福禄草亚属植物的染色体数目一致,为二者在分子系统发育框架下形成的独立分支提供核型证据。并讨论了5种垫状植物古多倍体物种形成的核型进化与中新世青藏高原及周边地区地质抬升的关联。     

Chromosome numbers, karyotypes and nuclear DNA contents from perennial polyploid groups ofCerastium (Caryophyllaceae)

Somatic chromosome numbers have been determined for the followingCerastium taxa:C. eriophorum (2n = 36),C. alpinum (2n = 72),C. transsylvanicum (2n = 108),C. arcticum (2n = 108),C. latifolium (2n = 36),C. carinthiacum (2n = 36),C. banaticum (2n = 36),C. arvense subsp.glandulosum (2n = 36),C. arvense subsp.arvense (2n = 72) andC. fontanum (2n = 144). Karyotypes of three diploid species (C. eriophorum, C. banaticum andC. latifolium), belonging to three different taxonomic groups, were analysed and found to be similar. The relative nuclear DNA contents of all taxa were determined by flow cytometry and, for five species, also by Feulgen cytophotometry. The values obtained by the two methods are similar. A comparison of nuclear DNA contents among diploids shows that values differ significantly between different taxonomic groups, and are correlated with average chromosome size. Within closely related polyploid groups nuclear DNA amounts increase from 2x- to 4x- and 6x taxa as 1 : 1.4 : 2.4 in theC. alpinum complex, whereas DNA amounts are doubled comparing 2x- and 4x-subspecies in theC. arvense complex.     

Genomic relationships between species of theElymus semicostatus group andElymus sensu lato (Poaceae)

Meiotic pairing behaviour in 19 interspecificElymus hybrids is reported and discussed. The hybrids were made between four species belonging to theE. semicostatus group of sect.Goulardia, viz.,E. semicostatus, E. abolinii, E. fedtschenkoi, andE. panormitanus (all 2n = 28), andElymus species of seven different sections, viz., sect.Clinelymiopsis:E. caucasicus (2n = 28); sect.Elymus:E. sibiricus (2n = 28); sect.Goulardia:E. caninus (2n = 28),E. trachycaulus (2n = 28), andE. tsukushiensis (2n = 42); sect.Hyalolepis:E. batalinii (2n = 42); sect.Hystrix:E. hystrix (2n = 28); sect.Macrolepis:E. canadensis (2n = 28); and sect.Turczaninovia:E. dahuricus (2n = 42). Chromosomal pairing at meiotic metaphase I indicated that the species of theE. semicostatus group are genomically closer to the tetraploidE. caucasicus and the hexaploid species, regardless of sectional origin, than to the other tetraploid species of sectionGoulardia. Highest meiotic pairing was found in hybrids involvingE. caucasicus, E. tsukushiensis, andE. dahuricus. The presence of pairing regulating genes inE. abolinii is suspected.     

Variation and geographical distribution of ploidy levels inPennisetum sectionBrevivalvula (Poaceae) in Burkina Faso,Benin and southern Niger

Pennisetum sect.Brevivalvula is a species complex characterized by polyploidy and apomixis. Ploidy level was assessed by DAPI-flow cytometry for 304 plants of the section, originating from Burkina Faso, Benin and southern Niger. The results were confirmed for 54 plants based on chromosome counts. The samples show four euploidy levels (with x = 9) distributed among five species:P. hordeoides (2n = 36, 54),P. pedicellatum (2n = 36, 45, 54),P. polystachion (2n = 18, 36, 45, 54),P. setosum (2n = 54), andP. subangustum (2n = 18, 36, 54). The geographical distribution of these ploidy levels seems related to major vegetation zones present in Africa. Diploid populations ofP. polystachion andP. subangustum were found in the Banfora area, in Burkina Faso.     

Comparative karyomorphology and interrelationships ofSelaginella in Japan

Karyomorphological comparisons were made of 16 native and cultivated species ofSelaginella in Japan. The somatic chromosome numbers are 2n=16 inS. boninensis; 2n=18 inS. doederleinii, S. helvetica, S. limbata, S. lutchuensis, S. nipponica, S. selaginoides, S. tama-montana, andS. uncinata; 2n=20 inS. biformis, S. involvens, S. moellendorffii, S. remotifolia, andS. tamariscina; 2n=30 inS. rossii; and 2n=32 inS. heterostachys. The interphase nuclei of all species examined are uniformly assigned to the simple chromocenter type. The metaphase karyotype of 2n=16 (x=8) is 8 m (=median centromeric chromosomes)+8(st+t)(=subterminal and terminal). The group of the species having 2n=18 (x=9) is heterogeneous karyomorphologically: The karyotype ofS. nipponica is 2n=18=6 m+12(st+t),S. tama-montana 10 m+2 sm(=submedian)+6(st+t), andS. uncinata 6 m+7 sm+5(st+t). Although the remaining five species have the common karyotype 8 m+4 sm+6(st+t), the values of mean chromosome length are variable. Another group of the specles having 2n=20 (x=10) is homogeneous, since all species have the same karyotypes 8 m+4 sm+8(st+t) and have similar chromosome size. The karyotype of 2n=30 is 12 m+6 sm+12(st+t) and is suggested to be a triploid of x=10, and 2n=32=16m+16(st+t), a tetraploid of x=8. Thus, three kinds of basic chromosome numbers, x=8, 9, 10 are present in JapaneseSelaginella examined, and their karyomorphological relationships are discussed.     

Tetraploids,triploids, and 2n pollen from diploid interspecific crosses with cassava

Summary Interspecific crosses of five cultivated cassava varieties (2n=36) were made with two related Manihot species, M. epruinosa (2n=36) and M. glaziovii (2n=36). From these diploid interspecific crosses, four spontaneous tetraploids (2n=4x=72) and two triploids (2n=3x=54) were isolated for the first time in cassava. Occurrence of relatively high frequencies (0.1%–35.6%) of 2n pollen and of apomixis seems to be associated with sexual polyploidization. The tetraploids and triploids were very vigorous and one of the tetraploids performed as well as the best variety in uniform yield trials conducted in Nigeria. These spontaneous polypoloids provide greater genetic variation and offer an opportunity to breed radically new cassava varieties. Approaches for isolating and utilizing the polyploid cassava clones for varietal and population improvement are discussed.     

Chromosomes of five artiodactyl mammals

Somatic chromosomes of six specimens belonging to the following five species of artiodactyls (Artiodactyla: Mammalia) are described: A female nilgai (Boselaphus tragocamelus), 2n=46; male baresingha (Rucervus duvauceli), two specimens, 2n=56; a female Himalayan tahr (Hemitragus jemlahicus), 2n=48; a female Kirk's dik-dik (Rhynchotragus kirki), 2n=46; and a male sambar (Cervus unicolor), 2n=58. In the baresingha and the sambar, one or more acrocentric chromosomes carried satellites on their long arms. ³H-thymidine radioautographs of cultured cells of the Himalayan tahr showed a long acrocentric chromosome to be late-replicating, suggesting that it is an X chromosome.     

On the karyotypes of the Neorhabdocoela species and karyological evolution of Turbellaria

The karyotypes of 10 species belonging to the Neorhabdocoela order (Turbellaria) are described: Proxenetes flabelliger, 2n=6 (Trigonostomidae), Promesostoma rostratum, 2n=12 (Promesostomatidae), Castrada sp., 2n=6, Rhynchomesostoma rostratum, 2n=6, Bothromesostoma esseni, 2n=10, Mesostoma lingua, 2n=8 (Typhloplanidae), Provortex karlingi, 2n=8 (Provorticidae), Halamovortex macropharynx, 2n=16 (Dalyellidae), Macrorhynchus crocea, 2n=16, and Gyratrix hermaphroditus, 2n=4 (Polycystidae). It is proposed that the karyotypes of the ancestral marine neorhabdocoel forms, as well as those of the other groups of turbellarians, must have consisted of 16–20 biarmed chromosomes. The processes of adaptation and speciation in each group seem to be accompanied by a gradual decrease in chromosome number to 2n=8–4, this being due to Robertsonian fusions and translocations. In some freshwater turbellarians the diploid number increased by polyploidisation. The same processes evidently took place in different groups of parasitic worms.     

A cytogenetic analysis of the genus Neodendrocoelum (Triclada,paludicola) from Lake Ohrid

Nine species of the genus Neodendrocoelum from Lake Ohrid, five from sublittoral and four from littoral regions, have a diploid chromosome complement 2n=32 and show a marked resemblance in their karyotypes, comprising four large pairs (group L), seven medium pairs (group M) and five small pairs (group S). Polymorphism has only been found in groups S. Variations in chiasma frequency in the species of this genus indicate that their meiotic systems are different. In these species the number of quadrivalent were found to be different in metaphase I. The process of speciation of this genus was manifested in the diploidization of autotetraploid species.