Four new species of Pleurosigma (Bacillariophyta) from Alexandria, Egypt

Four new species of Pleurosigma are described from the region of Alexandria in Egypt: P. williamsii sp. nov. , P. mariutensis sp. nov. , P. ramlehensis sp. nov. and P. rushdyensis sp. nov. The taxa had been previously misidentified as P. rigidum W. Sm., P. elongatum W. Sm., P. speciosum var. sumatricum H. Perag. and P. formosum W. Sm., respectively. Due to the close resemblance of P. williamsii, P. mariutensis , P. ramlehensis and P. rushdyensis to P. rigidum , P. elongatum , P. speciosum var. sumatricum and P. formosum and the lack of good illustrations of these previously described species, their valvar features are shown and discussed in relation to the new taxa. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 77–92.     

Geometric morphometrics, neural networks and diagnosis of sibling Taterillus species (Rodentia, Gerbillinae)

The lack of diagnostic traits in sibling species means that great quantities of biogeographical and ecological data held in museum collections cannot be utilized effectively, leading to underestimates of biodiversity. In this study we applied neural networks (NN) and canonical variates analyses (CVA) to landmark measurements on the skulls of the West African species Taterillus arenarius , T. petteri , T. gracilis and T. pygargus in an attempt to discriminate species previously identified unambiguously from their karyotypes. Among suggested differences, the relationship between inflation of the tympanic bullae and lower population density is discussed. Cross-validated classification rates did not exceed 73%. Two hypotheses are proposed to explain such high phenotypic similarity: morphological plasticity limited by environmental constraints and the possibility that speciation has been too recent to allow significant morphological divergence.  © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77 , 319−327.     

Thuja sutchuenensis: a rediscovered species of the Cupressaceae

After more than a century, the only conifer species listed as being extinct in the wild (EW) by IUCN-SSC has been rediscovered in the Dabashan Mountains of central China. The history, taxonomy, ecology and conservation of Thuja sutchuenensis are described, and illustrations, based on both the earliest and latest collection of botanical material of this tree, are provided. The taxonomic context of this rare species is discussed.  © 2002 The Linnean Society of London , Botanical Journal of the Linnean Society , 2002, 139 , 305–310.     

Riccia fruticulosa O.F.Müll., 1782 and blue Metzgeria (Marchantiophyta) in Europe

Riccia fruticulosa O.F.Müll., 1782 from Norway is a valid name, referring to Riccardia palmata (Hedw.) Carruth. In 1785 Dickson misidentified British plants of a blue Metzgeria as R. fruticulosa . The European blue species of Metzgeria is conspecific with M. violacea (Ach.) Dumort., which replaces M. fruticulosa auct. The true origin of the type of Jungermannia violacea Ach., 1805 is probably Tierra del Fuego (rather than Dusky Bay, New Zealand), where the species is widespread. Reports from Australasia, Asia and Africa are all erroneous. The blue colour of Jungermanniales is found only in living plants and is derived from the oil-bodies. In contrast, that of Metzgeria appears only after death; its biological function is unknown.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 142 , 229−235.     

Clarification of the taxonomic status and relationships of Pteridium caudatum (Dennstaedtiaceae) in Central and South America

Contemporary systematic treatments of the Central and South American bracken ferns in the genus Pteridium Gled. ex Scop. recognize morphotype caudatum as either a full species or a variety of P. aquilinum (L.) Kuhn. Geographically representative sporophytes of morphotype caudatum , including the type in the Linnaean Herbarium, are shown using spore size, guard-cell length and morphology of the cells of the false indusium to be tetraploid (based on 4 n  = 208). DNA fingerprinting of field-collected Venezuelan samples supports the generalization that morphotype caudatum is a fertile allotetraploid containing genomic elements otherwise distinctive of the southern hemisphere diploid P. arachnoideum (Kaulf.) Maxon, together with elements characteristic of northern hemisphere diploids including the North American P. aquilinum var. pubescens Underw. and P. aquilinum var. pseudocaudatum (Clute) A. Heller. Evidence of genetic isolation from taxa with overlapping distributions, as well as morphological, biochemical and ecological data, validate recognition of P. caudatum (L.) Maxon at species level. Heterogeneity observed within P. caudatum is consistent with multiple origins through independent hybridization events. Pteridium caudatum is strikingly analogous to the tropical Asian/Australasian allotetraploid P. semihastatum (N. Wallich ex J. G. Agardh) S. B. Andrews [= P. yarrabense (Domin) N. A. Wakef.].  © 2002 The Linnean Society of London . Botanical Journal of the Linnean Society , 2002, 140 , 237−248.     

Iris stenophylla Hausskn. & Siehe ex Baker from Turkey and its cytology

A morphological study, both in the field and from herbarium material, showed that there are no convincing characteristics separating the Turkish endemics Iris stenophylla ssp. stenophylla and ssp. allisonii . A cytological survey revealed chromosome numbers of 2 n  = 24, 26 and 26 + 1B. No variation in either chromosome number or karyotype was found in ssp. allisonii , which always had 2 n  = 26, although the chromosome number and karyotypes of ssp. stenophylla were variable. Since neither morphological nor cytological differences were sufficient to separate the two subspecies, I. stenophylla ssp. allisonii is therefore reduced to a synonym of I. stenophylla .  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 115−127.     

16S mitochondrial sequences associate morphologically dissimilar males and females of the family Phoridae (Diptera)

The genus Phora (Diptera, Phoridae) includes more than 50 species widely distributed in temperate regions of Eurasia and Africa. Taxonomic identification of most species is based upon the morphology of the male hypopygium: hence for many species, including the type species of the genus, females are unknown. We used mitochondrial 16S ribosomal RNA sequences to match males with previously unidentified females from Phora atra , P. stictica , and P. holosericea . We then identified morphological characters that allow identification of females of P. atra and P. stictica without recourse to DNA sequencing. Our results show that small scale sequencing can aid in the development of taxonomic characters for use in the field to identify previously cryptic females. This iterative method of identifying populations genetically followed by re-examination of morphology should allow development of better keys for rapid identification of heretofore cryptic populations of insects. We also found that sequences from individual of P. holosericea from Cambridge, England and Malakhovka, Russia, were more similar to each other than to sequences from a conspecific fly also collected in Cambridge. This result suggests that there is previously un-suspected population structuring in this species.  © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77 , 267–273.     

Three new species of Echinops (Compositae, Cynareae) from Iran

As a result of extensive collections and subsequent determinations made in recent years through most regions of Iran (now preserved in herbarium TARI), three new species of Echinops ( E. longipenicillatus, E. procerus and E. shahrudensis ) are described and illustrated. All belong to E . sect. Oligolepis Bunge, which is endemic to Iran.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 181–186.     

Clarification of the name Nothofagus alpina and a new epithet for a Nothofagus hybrid

Arguments in favour of using Nothofagus alpina (Poepp. & Endl.) Oerst. (Fagaceae) rather than N. procera Oerst. or N. nervosa (Phil.) Krasser as the correct name for rauli are presented. We also refute suggestions that N. alpina is based on hybrid material. The hybrid of N. alpina with N. obliqua (Mirb.) Blume is formally described as N . ×  dodecaphleps Mike L. Grant & E. J. Clement and a key to the deciduous taxa of Nothofagus is provided.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 447–451.     

The genus Goniothalamus (Annonaceae) in Sumatra

A comprehensive taxonomic revision of the species of Goniothalamus (Blume) Hook. f. & Thomson (Annonaceae) occurring in Sumatra and adjacent islands is presented for the first time. Fourteen species are recognized, including six endemics that are described as new to science ( G. acehensis, G. alatus, G. dewildei, G. loerzingii, G. longistaminus and G. miquelianus ). In addition, two species are newly recorded from Sumatra, viz. G. parallelivenius Ridl. (previously reported from Borneo), and G. wrayi King (previously reported from Peninsular Malaysia). The extensive nomenclatural confusion regarding the application of the names G. costulatus Miq. and G. opacus Bakh. f. is clarified: the names are shown to be synonymous, with the former having nomenclatural priority. The utility of specific taxonomic characters are also discussed, with particular emphasis on petal indumentum, staminal connective shape, ovary indumentum, stigma shape, monocarp size and shape, and seed indumentum. Biogeographical relationships in the genus are discussed, and the significance of the Barisan mountain range and the Quaternary volcanic tuffs around Lake Toba are highlighted as potential ecological barriers limiting dispersal.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 225–254.     

Systematics of the tribe Podalyrieae (Fabaceae) based on DNA, morphological and chemical data

Phylogenetic relationships among nine genera and 28 species of the southern African tribe Podalyrieae were estimated from sequences of the internal transcribed spacer (ITS) of nuclear ribosomal DNA as well as morphological and chemical data. Morphological and ITS sequence data produced cladograms with similar topologies, both supporting the monophyly of Podalyrieae (excluding Hypocalyptus ). The combined data sets indicate that subtribe Xiphothecinae are monophyletic, but embedded within Podalyriinae. The high degree of congruence between previous taxonomic hypotheses and those based on DNA data provides further evidence for the utility of ITS sequences in studying phylogeny.  © 2002 The Linnean Society of London , Botanical Journal of the Linnean Society , 2002, 139 , 159–170.     

Experimental evidence for adaptive phenotypic plasticity in a rock-dwelling cichlid fish from Lake Victoria

We demonstrate adaptive phenotypic plasticity (PP) in Neochromis greenwoodi , a rock-dwelling haplochromine cichlid from Lake Victoria. Adaptive phenotypic plasticity will enhance the chance of survival and reproduction in changing or novel environments. For rock-dwelling cichlids it may contribute to the success of settlement after migration between rocky outcrops or islands, since newly colonized patches of rock may offer different food regimes and different competitors. In our experiments, we simulated such situations by raising fry on different diets and with different competitors. We chose diet treatments in such a way that we could predict the direction of anatomical changes from functional demands. We expected an indirect effect of interspecific competition: selectively removing one prey-type by the competing species would leave N. greenwoodi with the other. We found the predicted phenotypic responses to food in trophic traits of N. greenwoodi . However, in the current experimental set-up we did not find a differentiating effect of species of competitor. We discuss the possible role of PP in allopatric and sympatric speciation.  © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77 , 185−192.     

Two new basal crocodylomorph archosaurs from the Lower Jurassic and the monophyly of the Sphenosuchia

We report on and name two new taxa of basal crocodylomorph archosaurs from the Lower Jurassic, Litargosuchus leptorhynchus gen. et sp. nov. , from the upper Elliot Formation (Stormberg Group) of South Africa, and Kayentasuchus walkeri gen. et sp. nov. , from the Kayenta Formation (Glen Canyon Group) of Arizona, USA. Examination of this material led to a reconsideration of basal crocodylomorph interrelationships. A phylogenetic analysis found no support for the monophyly of Sphenosuchia.  © 2002 The Linnean Society of London. Zoological Journal of the Linnean Society , 2002, 136 , 77–95.     

Transfer cells in the seeds of Boraginales

The presence of transfer cells (TCs) in the seeds of Boraginales (Boraginaceae s.s. , Hydrophyllaceae, Heliotropiaceae, Ehretiaceae, Cordiaceae and Lennoaceae) has been reported but has not hitherto been studied systematically. This study, surveying the seed anatomy of 50 species of Boraginales, demonstrates that in Heliotropiaceae, Cordiaceae, Ehretiaceae and Lennoaceae, TCs are found in an uninterrupted course from the placenta via the funicle to the seed coat. These families are characterized by indehiscent fruits with a protective endocarp. The TCs may act as a sponge, thus promoting rapid germination when sufficient water is available. In Hydrophyllaceae, which have capsular fruits, TCs are often found but have a different structure and are restricted to the seed coat. Boraginaceae s.s. on the other hand are characterized by a complete absence of TCs in their seeds. The presence of TCs in seeds is considered as a synapomorphic trait and appears to be phylogenetically informative.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 155−164.