Cryptic species diversity in a widespread bumble bee complex revealed using mitochondrial DNA RFLPs

Cryptic species diversity is thought to be common within the class Insecta, posing problems for basic ecological and population genetic studies and conservation management. Within the temperate bumble bee (Bombus spp.) fauna, members of the subgenus Bombus sensu stricto are amongst the most abundant and widespread. However, their species diversity is controversial due to the extreme difficulty or inability morphologically to identify the majority of individuals to species. Our character-based phylogenetic analyses of partial CO1 (700 bp) from 39 individuals spread across their sympatric European ranges provided unequivocal support for five taxa (3–22 diagnostic DNA base pair sites per species). Inclusion of 20 Irish specimens to the dataset revealed ≥2.3% sequence divergence between taxa and ≤1.3% within taxa. We developed a PCR-RFLP based method for unequivocally distinguishing amongst the four cryptic European taxa of this subgenus, B. cryptarum, B. lucorum, B. magnus and B. terrestris, and used it to analyse 391 females of the former three species collected across Ireland, all of which could be unambiguously assigned to species. Bombus lucorum was the most widely distributed and abundant of the cryptarum–lucorum–magnus species complex, comprising 56% of individuals, though it was significantly less abundant at higher altitudes (>200 m) whilst B. cryptarum was relatively more abundant at higher altitudes. Bombus magnus was rarely encountered at urban sites. Both B. lucorum and B. terrestris are nowadays reared commercially for pollination and transported globally. Our RFLP approach to identify native fauna can underpin ecological studies of these important cryptic species as well as the impact of commercial bumble bees on them.     

A numerical taxonomic study of thePolygonum aviculare complex (Polygonaceae) in Belgium

16 morphological characters were assessed in 300 plants sampled from 27 populations ofPolygonum aviculare sensu lato representative of the whole ecological range of the species in Belgium. The three multivariate treatments performed, namely principal component analysis, cluster analysis and discriminant analysis provide evidence thatP. aviculare can be divided in 4 units, roughly corresponding to the four taxa recognized byChrtek. However, the results point out that subsp.monspeliense and subsp.calcatum should be included at the varietal rank within respectively subsp.aviculare (=P. heterophyllum) and subsp.aequale (=P. arenastrum) as defined byLindman. Fruit dimensions, fruit shape and tepal length are the most discriminant characters for separating the four taxa, while several other characters are discriminant at the population level only. The evolutionary significance of the variation pattern of the whole complex is discussed in terms of life history differentiation and ecological specialization.     

Electrophoretic confirmation of the intergeneric hybrid ×Ruttyruspolia (Acanthaceae)

A plant collected in South Africa in the early 1960's has been considered an intergeneric hybrid with the parental taxa beingRuspolia hypocrateriformis (Vahl)Milne-Redhead var.australis Milne-Redhead andRuttya ovata Harv. The intermediate morphology of the plant provided the strongest evidence of its hybrid origin. The natural hybrid, named formally as ×Ruttyruspolia A. Meeuse & de Wet, is highly sterile. Crosses between the two presumed parental taxa produced two plants that are very similar to the putative natural hybrid. We had examined the presumed parental species and the natural and artificial hybrids using enzyme electrophoresis. The two parental species are highly differentiated at genes specifying soluble enzymes; they have a genetic identity of 0.51. They have no common alleles at two genes, and contain alternative alleles in very different frequencies at two loci.Ruttya andRuspolia exhibit both unique and common alleles at two additional genes. The natural and artificially produced plants of ×Ruttyruspolia are identical electrophoretically and contain alleles unique to each of the parental species at two genes. In addition, individuals of ×Ruttyruspolia combine alternative high frequency alleles from each parent at two loci. Allozymes provide strong confirming evidence for the hybrid origin of naturally occurring ×Ruttyruspolia because the products of specific alleles either unique to or highly characteristic of the two putative parental taxa are found combined in ×Ruttyruspolia.     

Multivariate morphometric and allozymic analysis of theConospermum taxifolium (Proteaceae) species complex

A morphometric analysis of 18 attributes of 110 plants of theConospermum taxifolium complex suggests that it consists of three polythetically distinct taxa, corresponding to the traditional concepts ofC. taxifolium Smith s. str.,C. ericifolium Smith andC. ellipticum Smith. Discrimination is possible on the basis of leaf but not flower attributes. Analysis of allozymic variation indicates that the taxa are also genotypically differentiated.C. ericifolium andC. ellipticum are geographically isolated from each other but not fromC. taxifolium, andC. taxifolium is usually ecologically segregated from the other two taxa. Where this ecological segregation breaks down, morphological intermediates sometimes occur as the result of hybridization.     

The phylogenetic relationships ofByblis andRoridula (Byblidaceae-Roridulaceae) inferred from partial 18S ribosomal RNA sequences

The phylogenetic relationships of the angiosperm generaByblis andRoridula have been the subject of ongoing taxonomic controversy. Twenty-eight taxa of varying degrees of alleged relationship, including 3 members of theWinteraceae (as an outgroup), were investigated using partial sequences of 18S rRNA (small subunit) and also compared against the morphological data set fromHufford's (1992) cladistic treatment of 80 members of theRosidae-Asteridae. The morphological analysis placed the two genera in a clade with theSarraceniaceae in theCorniflorae-Asterid group as a sister taxon to anEricales-Hydrangeales clade. The 18S rRNA analysis supports the recently publishedrbcL DNA analysis ofAlbert & al. (1992), withRoridula joined to taxa in the lowerRosidae, butByblis joining instead to members of theAsteridae near theSolanaceae. Comparisons for congruence between the three analyses placeByblis in the higher Asterid group near theSolanaceae, andRoridula possibly nearer theSarraceniaceae andEricales. These results imply that the traditional morphological characters used to relate the two genera are possibly the result of convergence towards similar ecological and life-history strategies rather than synapomorphies.     

The perennial taxa ofCrucianella (Rubiaceae) in SW. Asia and their eco-geographical differentiation

The perennial taxa ofCrucianella in Asia form a coherent group, apparently diploid (x = 11) and outbreeding throughout, and should be placed into sect.Roseae. This Irano-Turanian group has its centre of diversity in the mountain systems south of the Caspian Sea and reaches with outposts NE. and E. Anatolia, NE. Iraq, S. Iran and C. Asia. Four species and 13 subspecies (within the polymorphicC. gilanica) are recognized, described (partly as new), and illustrated (Figs. 1–6). Conspectus, keys and distribution maps (Figs. 7 and 8) as well as plesio- and apomorphic character states and data on size of areas are provided (Table 1). There is an obvious correlation between more plesiomorphic taxa with smaller areas in the distribution centre of the group, and more apomorphic taxa with larger areas towards its periphery (Fig. 9). These findings are linked to a working hypothesis on the evolution of the group.Dedicated to Prof. DrLothar Geitler on the occasion of his 90th birthday.     

A reexamination of infraspecific taxa of a wild potato,Solanum microdontum (Solanum sect.Petota:Solanaceae)

Current taxonomic interpretations ofSolanum microdontum Bitter partition the species into two or three infraspecific taxa, variously recognized as subspecies or varieties. The present study reexamines these taxa using morphological data from four individuals each of 69 accessions from most of the range of the species, planted in a common field plot. Our results show that the character states used to recognize infraspecific taxa inS. microdontum often vary within accessions and have no correlation with geography. We conclude that past hypotheses have used typological concepts and that infraspecific taxa are not warranted. This study questions other hypotheses of infraspecific taxa in sect.Petota.     

Chromosome number,morphology, pairing,and DNA values of species and hybrids in the genusFallopia (Polygonaceae)

The taxa in this study have in the past been treated together in sect.Tiniaria Meissner ofPolygonum L. s.l., and more recently the large erect rhizomatous herbaceous perennials have been separated from the twining annuals and perennials as the generaReynoutria andFallopia respectively. These taxa range in ploidy level from diploid to octoploid, with base numbers of both 10 and 11 present. The plants are primarily Asiatic in distribution, although many of the large erect perennials are now naturalized in many parts of Europe. Cytological examination has revealed the presence of a number of previously unknown hybrid taxa in the British Isles. The readiness with which hybridisation occurs between taxa of differing base number and ploidy level, and similarities revealed in chromosome morphology, meiotic pairing and in DNA C-value, suggest to the authors that these two genera are best amalgamated underFallopia.     

Overcoming seed dormancy in ex situ plant germplasm conservation programmes; an example in the endemic Argyranthemum (Asteraceae: Anthemideae) species from the Canary Islands

Germplasm of 21 diverse Argyranthemum taxa was collected from contrasting ecological zones in the Canary Islands. Seed dormancy was considerable in the majority of taxa. Extensive investigations, based on a germination test procedure algorithm for Asteraceae, with achenes from ray and disc florets of five contrasting taxa identified a procedure to promote full (85%) germination of the seeds from both ray and disc florets of all five taxa; viz, excision of the seeds from the achenes, followed by testing at 15°C with 2.6×10^-3 m GA₃ co-applied. Subsequent tests showed that this regime was effective in promoting full germination in seeds from both ray and disc florets of the remaining 16 taxa. The results are discussed in the context of ex situ plant germplasm conservation.     

Comparative analysis of C-band karyotypes inCrepis praemorsa subsp.praemorsa and subsp.dinarica

Crepis incarnata subsp.dinarica (G. Beck)Hayek is nowadays considered as a subspecies ofC. praemorsa (L.)Tausch. Comparative analyses of Feulgen karyotypes demonstrate great similarities, but remarkable differences in the presence and the distribution of the constitutive heterochromatin in the two taxa are detected by using the Giemsa differential staining technique (C-banding). This favours their specific distinctness.     

Cytotaxonomische Untersuchungen in der Artengruppe desRanunculus alpestris (Ranunculaceae)

Morphological and cytological investigations as well as crossing experiments were carried out with the 5 species of theRanunculus alpestris group (R. alpestris L.,R. traunfellneri Hoppe,R. bilobus Bertol.,R. crenatus Waldst. etKit.,R. magellensis Ten.). A key to the species is presented; localities and distribution are given in addition to extensive diagnoses. Crossing experiments between the 5 taxa were successful (F₁-F₃ individuals, backcross types, tripeland quadrupelbastards); the morphology of the experimentally obtained F₁-hybrids was mostly intermediate. All 5 species as well as all hybrids have a chromosome number of 2n = 16; there is no statistically significant difference between the karyotypes of the 5 taxa. According to the results of the morphological investigations and the crossing experiments we can distinguish 2 subunits of very closely related species: a)R. alpestris, R. traunfellneri, R. bilobus; b)R. crenatus, R. magellensis. The speciation within the group ofRanunculus alpestris is discussed.

     

Chemistry and micromorphology of compound epicuticular wax crystalloids (Strelitzia type)

Certain non-liliiflorous taxa within the monocotyledons (e.g.,Strelitzia, Heliconia, Typha) are characterized by compound epicuticular wax rodlets (Strelitzia type). Similar rodlets are also encountered on the surface of the dicotyledonous plantBenincasa hispida (Thunb.)Cogn. Chemical analysis of the surface wax from both sources showed that the rodlets are chemically distinct. The rodlets of the monocotyledons consist exclusively of aliphatic wax lipids, mainly wax esters. In contrast, the rodlets ofBenincasa are cheifly composed of triterpenol acetates and triterpenols. Formation of rodlets is therefore interpreted as ultrastructural convergency. It is concluded that taxonomical studies on wax crystalloids can be misleading when interpreted in terms of micromorphology of crystalloids only.     

Species boundaries,phylogenetic relationships,and ecological differentiation inAnthriscus (Apiaceae)

Species boundaries and phylogenetic relationships of 17 taxa ofAnthriscus (Apiaceae), with special emphasis on the critical sect.Cacosciadium, were explored using morphological data with principal component analysis, phenetics, and phylogenetics. The analyses did not provide satisfactory resolution of taxa from sect.Cacosciadium and only four species were retained. The total number of species was reduced to nine. Sect.Cacosciadium is distinguished by only two synapomorphies while sects.Anthriscus andCaroides are better supported. Present geographic and ecological variation suggests that the radiation ofAnthriscus occurred through divergence of peripheral isolated populations adapting to different habitats: high montane meadows and screes, shady climax forests, and seasonally dry habitats at lower altitudes. The adaptive significance of particular morphological traits is discussed.     

Cytotaxonomy and breeding system of the genusBiscutella (Cruciferae)

Chromosome counts were determined for 46 populations ofBiscutella representing 28 taxa. The genus was found to contain diploid taxa with 2n = 12, 16 and 18, tetraploid taxa with 2n = 36 and hexaploid taxa having 2n = 54.B. laevigata L. s. l. consists of diploid and tetraploid populations which are poorly differentiated morphologically. TetraploidB. laevigata s. l. and hexaploidB. variegata Boiss. & Reuter (s. l.) are characterized by chromosomal instability. The variation in chromosome numbers and the occurrence of polyploidy is discussed in relation to the taxonomy of the genus. An investigation of the breeding system showed that most of the annual species were self-compatible and partly inbreeding and most of the perennial species self-incompatible and, therefore, outbreeding, while one annual species,B. cichoriifolia Loisel., showed both systems.     

Contribution à l'Etude Cytotaxinomique desSideritis sectionEmpedoclea (Labiatae)

The author has proceeded with a cytotaxonomical study of the genusSideritis L. Chromosome numbers (mostly new) are reported for about twenty taxa from sectionEmpedoclea (Rafin.)Benth. This section occupies a very isolated position within the genus and has evolved quite independently.

     

The flavonoids of theFagonia bruguieri complex (Zygophyllaceae)

Seven flavonol glycosides were identified from the main taxa of theF. bruguieri complex. Of these, kaempferol 3-rhamno-galactoside, Quercetin 3-rhamnogalactoside and Quercetin 3-galactoside are new records for the genusFagonia L. and theZygophyllaceae s. str. The distribution of these flavonoid glycosides is discussed with respect to the morphology, chemosystematics, and possible phylogeny of the complex and the genus.Dedicated to Hofrat Univ.-Prof. DrKarl Heinz Rechinger on the occasion of his 80th birthday.     

Revision of Hyolitha from the Ordovician of Estonia

Topotype specimens of the Middle OrdovicianHyolithes acutus Eichwald, 1840, which is the type of the genus that lent its name to a family, order, class, and even phylum according to some, andH. latus Eichwald, 1860 allow that genus and those species to be firmly established on a sound, morphologic basis. In addition, preservation of the types ofHyolithes striatus Eichwald, 1860 is sufficiently good to warrant reassignment toDorsolinevitus Syssoiev, 1958. In contrast, the type ofH. insularis Eichwald, 1860 is incompletely preserved, and this species is not recognizable beyond the type material. The concept of the family Hyolithidae is revised to more closely conform to the morphology ofHyolithes, with authorship herein ascribed toSyssoiev (1958) rather than toNicholson (1872). The stratigraphic distribution of these taxa suggests thatHyolithes as defined herein first appears in the Middle Ordovician, but extends into at least the Lower Devonian, as suggested by two species from the Barrandian region of the Czech Republic. Their geographic distribution further re-enforces the notion of two distinct paleobiogeographic provinces based on hyoliths, a Mediterranean province and Baltic province, with almost no mixing of hyolith faunas during the Ordovician.      

Heliantheae sensu lato (Asteraceae), clades and classification

The interrelationships within theHeliantheae s. lato and the closely relatedEupatorieae are analyzed and discussed. The basis to this discussion is a cladistic analysis of 141 morphological characters (172 apomorphic states) scored for 97 genera. TheHeleniae s. lato, a subgroup of theHeliantheae s. lato, are paraphyletic, and a monophyletic group corresponding largely to theHeliantheae s. str. is recognized. TheEcliptinae sensuRobinson are polyphyletic. TheCoreopsidinae form an ingroup in theHeliantheae s. str. TheTageteae (Pectidinae) and theMadieae (Madiinae) are two separate branches within the helenioid assemblage of taxa.     

Variation and evolution inLinum tenuifolium (Linaceae)

The phenetic variation inL. tenuifolium s.l. was assessed using multivariate analyses of 27 characters found to be variable within the species. These results are discussed and interpreted in the context of the reproductive biology, chromosome number and ecological responses of the taxa. Evidence suggests that both the self-compatible and tetraploid races were derived independently from a self-incompatible, diploid type. Although no taxonomic scheme is compatible with all of the evidence presented, the study supports a recent decision to recognize four taxa at subspecific level.     

The genusCarex (Cyperaceae) in the Flora Iranica area

88 species and 20 subspecies ofCarex, altogether 94 taxa, occur in the area ofRechinger's Flora Iranica. Of these, 48 taxa, have an Euro-Siberian, 11 an Irano-Turanian and 35 a Central Asiatic distribution, the last including five species with connections to E. and tropical SE. Asia. The Saharo-Sindian element is missing. Endemic taxa are found in all groups. Eight taxa, endemic to the NW. Himalayas occur in the E. part of the area. The Euro-Siberian taxa are concentrated in the NW. of the area, but have connections to the east; similarly, Central-Asiatic taxa are concentrated in E. Afghanistan and N. Pakistan, but have connections to the west. Some Euro-Siberian taxa are widely distributed in the area, but avoid the most arid regions. The Irano-Turanian taxa are few and extend from Egypt through the area of Flora Iranica to Kazakhstan SSR and Central China.Dedicated to Hofrat Univ.-Prof. DrK. H. Rechinger on the occasion of his 80th birthday.