Bryophytes of St Helena,South Atlantic Ocean. 6. Cheilolejeunea (Spruce) Schiffn. (Jungermanniales: Lejeuneaceae), including C. microscypha (Hook.f. & Taylor) M.Wigginton,comb. nov. and C. rotalis (Hook.f. & Taylor) M.Wigginton,comb. nov.

Abstract

Two little known species of Cheilolejeunea, C. microscypha (Hook.f. & Taylor) M.Wigginton, comb. nov. (a reinstated St Helena liverwort), and C. rotalis (Hook.f. & Taylor) M.Wigginton comb. nov., endemic to St Helena, South Atlantic Ocean, are described and illustrated, and oil bodies of C. ascensionis (Hook.f. & Taylor) Grolle are newly described and illustrated.     

Bryophytes of St Helena,South Atlantic Ocean. 8. Lepidopilidium crispifolium,sp. nov. (Hookeriales,Pilotrichaceae)

Abstract

A new species of Lepidopilidium (Pilotrichaceae, Hookeriales), L. crispifolium, sp. nov. from St Helena, South Atlantic Ocean is described and illustrated.     

Bryophytes of St Helena,South Atlantic Ocean. 1. Three new species of Cololejeunea (Jungermanniales,Lejeuneaceae), C. dianae sp. nov., C. sanctae-helenae sp. nov. and C. grossestyla sp. nov.

Abstract

Three new species of Cololejeunea, C. dianae M. Wigginton, C. sanctae-helenae M. Wigginton and C. grossestyla M. Wigginton are described and illustrated from St Helena, South Atlantic Ocean. Details of their distributions are provided, and differences between the new taxa and other species of Cololejeunea are discussed. This is also the first report of the genus Cololejeunea from St Helena.     

Generic relationships of Oparanthus and Petrobium,especially with reference to Bidens (Compositae,Heliantheae, Coreopsidinae)

Oparanthus with two species from the Tubuai Islands of the South Pacific Ocean and the monotypicPetrobium from St. Helena in the South Atlantic are judged to belong more properly withinBidens. Comparisons of diagnostic morphological features are provided, and the necessary combinations are made, includingBidens rapensis (F. Brown) Stuessy andB. tubuaiensis (F. Brown) Stuessy.     

Biological control of an exotic scale, Orthezia insignis Browne (Homoptera: Ortheziidae), saves the endemic gumwood tree, Commidendrum robustum (Roxb.) DC. (Asteraceae) on the island of St. Helena

St. Helena is a small South Atlantic island with a highly degraded, but internationally significant, terrestrial flora. The 2500 remaining gumwoods, Commidendrum robustum, are an important part of this remnant flora. In 1991, a South American scale insect, Orthezia insignis, was identified attacking the gumwood trees. By 1993, severe infestations had killed over 100 trees. If the number of dead trees had continued to increase exponentially, all 2500 trees would have died by 1995. This outcome was likely given abundant alternative host plants, and lack of natural enemies of O. insignis. Host range tests showed that the other members of the endemic genus Commidendrum were also at risk. The coccinellid predator, Hyperaspis pantherina, was released on St. Helena in 1993. H. pantherina numbers increased from 1994, coinciding with a 30× decrease in scale numbers. Scale outbreaks have not been reported on St Helena since 1995, and culturing of H. pantherina was discontinued because insufficient O. insignis prey could be found in the field. Extensive blackening from sooty molds on the surviving trees in 1995 suggested that the predator was effective just in time to prevent death of most trees. H. pantherina appears to have saved the field population of a rare endemic plant from extinction.     

The fern genus Elaphoglossum section Lepidoglossa (Dryopteridaceae) in Africa,Macaronesia, the mid‐Atlantic and southern Indian Ocean Islands

Elaphoglossum section Lepidoglossa in Africa, Macaronesia (Azores and Madeira), the mid‐Atlantic Ocean Islands (St Helena, Gough and Tristan da Cunha Island groups) and the southern Indian Ocean Islands (Marion and Prince Edward Islands) is reviewed. Fifteen Elaphoglossum species from this region are ascribed to the section. A new species, Elaphoglossum rivularum , confined to the Chimanimani Mountains in eastern Zimbabwe and formerly ascribed to E. kuhnii from West Africa, is described. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 165 , 20–63.     

Genetic structure among Charadrius plovers on the African mainland and islands of Madagascar and St Helena

Colonization of islands by long-distance dispersers has great impact on genetic diversification among populations and may spearhead speciation events. We investigated intra- and interspecific divergence in Charadrius plovers with populations on mainland Africa, Madagascar and St Helena. We analysed microsatellite loci and sequence data from four nuclear and two mitochondrial gene regions. Charadrius plovers are shorebirds with high dispersal and mobility. Our results confirmed genetic differentiation between Madagascar and mainland populations of three plover species (White-fronted Plover Charadrius marginatus, Kittlitz's Plover Charadrius pecuarius and, based on sequence data only, Three-banded Plover Charadrius tricollaris) but highlight substantial variation in levels of intraspecific divergence among the three species. Namely, the Kittlitz's Plover, a dispersive habitat generalist with a polygamous mating system, exhibited lower island–mainland differentiation (0.05% COI sequence divergence) compared with the two monogamous species, the White-fronted Plover (0.6% COI divergence) and Three-banded Plover (1.6% COI divergence). In addition, past colonization of the islands of St Helena and Madagascar by ancestors of today's Kittlitz's Plover has led to the evolution of two endemic island species, the Madagascar Plover Charadrius thoracicus and the more closely-related St Helena Plover Charadrius sanctaehelenae. We discuss the factors driving species differences in island–mainland divergence and highlight the importance of conserving genetically unique island populations and island habitats to safeguard future evolutionary potential.     

Phylogenetic relationships withinPelargonium sect.Peristera (Geraniaceae) inferred from nrDNA and cpDNA sequence comparisons

Phylogenetic analysis of nrDNA ITS and trnL (UAA) 5 exon-trnF (GAA) chloroplast DNA sequences from 17 species ofPelargonium sect.Peristera, together with nine putative outgroups, suggests paraphyly for the section and a close relationship between the highly disjunct South African and Australian species of sect.Peristera. Representatives fromPelargonium sectt.Reniformia, Ligularia s. l. andIsopetalum (the St. Helena endemicP. cotyledonis) appear to be nested within thePeristera clade. The close relationship between the South African and AustralianPeristera is interpreted as being caused by long-range dispersal to Australia, probably as recent as the late Pliocene.     

Growth rates and agar properties of three gracilarioids in suspended open-water cultivation in St. Helena Bay, South Africa

Relative growth rates (RGRs), yields and agar characteristics of threegracilarioid isolates (Gracilariopsis sp. from St. Helena Bay, and Gracilaria gracilis isolates from Langebaan Lagoon and Saldanha Bay) weremeasured to assess the suitability of a site in St. Helena Bay for suspendedcultivation. The gracilarioids were grown on polypropylene ropes and`netlon' lines, and the RGRs were 4.0–11.0% d<sup>-1</sup> and 5.0–7.0%d<sup>-1</sup>, respectively. The RGR of the Langebaan isolate of G. gracilis grown on ropes was significantly higher than the RGR of otherisolates. The mean net yield for the Langebaan isolate grown on `netlon'lines was 2.6 ± 0.9 kg wet wt m^-2 30 day^-1. Thecultured gracilarioids were extracted for native and alkali treated agars. Themean native agar yield over the entire period was 39.0% dry wt. Alkalipretreatment reduced the yield by 55%, but significantly increased gelstrength. High gel strengths (>750 g cm^-2) were measured inagars from Gracilariopsis sp. and Saldanha Gracilaria gracilis inmid-summer and winter. The dynamic gelling and melting temperatures ofnative and alkali treated agars varied among the gracilarioids. The meangelling and melting temperatures of agars were about 39.0 ^°C and86.0 ^°C, respectively. The 3,6-AG content ranged from 29% to38% for native agars and 34–45% for alkali treated agars. While theseresults indicate that this site is suitable for gracilarioid cultivation, occasionallow-oxygen events in St. Helena Bay lead to production of hydrogensulphide in the sea water (`black tides'). Such events killed most inshorebiota (including seaweeds) in 1994 and 1998. This frequency (on average1–2 per decade) and duration (maximum 2 weeks) would have to beconsidered in planning commercial seaweed farming in St. Helena Bay.     

Comparative feeding strategies of yellowfin tuna around St Helena and adjacent seamounts of the South Atlantic Ocean

Yellowfin tuna are the mainstay of the traditional tuna fisheries in St Helena waters, but there is limited knowledge of their ecology and feeding behaviour in the area. In this study yellowfin tuna stomach contents were used to assess spatio-temporal changes in feeding strategy and consider the role of tuna in the local ecosystem. Comparisons of the feeding spectra of yellowfin tuna between inshore regions of St Helena and oceanic seamounts demonstrated that in both areas the species was largely piscivorous. In inshore waters yellowfin consumed more neritic fauna, including significant numbers of crab megalopa, whereas around seamounts the diet included a greater diversity of epi- and mesopelagic fish and squids. The most important fish prey species in inshore waters was the St Helena butterflyfish Chaetodon sanctahelenae, and around seamounts was the pufferfish Lagocephalus lagocephalus. Results indicate that the diet spectrum of yellowfin tuna in St Helena waters is relatively similar to those of conspecifics living in waters with relatively low productivity, with strategies indicative of food-poor ecosystems. The availability of coastal fauna may make areas around islands and seamounts more attractive for feeding aggregations of yellowfin tuna, compared to the open ocean. The relatively unselective feeding of yellowfin tuna means that stomachs can provide valuable data on the species diversity, particularly in remote areas with limited opportunities for dedicated research expeditions.     

Lichens of St Helena and Ascension Island

Lichens are the dominant organisms on most of the South Atlantic island of St Helena. In total, 220 different species were found during a recent survey, most of which have never been reported from the island. Previously, less than 50 lichen species were reported from the island, one half of which are most probably incorrect records. The total number of lichens known from the island now stands at 225. Most species could be identified, but the following, most probably endemic, species are described as new to science: Dolichocarpus seawardii , which is only the second species in this genus, the type being from Chile; Dermatiscum pusillum , which is only the third species in this African genus; Dimelaena triseptata ; Xanthoparmelia beccae ; and four Ramalina species, Ramalina geniculatella , R. ketner‐oostrae , R. rigidella , and R. sanctae‐helenae . The lichen flora has many species in common with that of the geologically much younger Ascension Island, where just under 100 species were recently found by the author, most of which are equally new to that island. Lecanora sanctae‐helenae, previously known as the only endemic lichen of St Helena, was also found to be abundant on Ascension Island. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 147–171.     

Phylogenetic relationships between Leymus (Poaceae,Triticeae) and related diploid Triticeae species based on isozyme and genome-specific random amplified polymorphic DNA (RAPD) markers

Abstract

To investigate the phylogenetic relationships between Leymus and related diploid species of the Triticeae tribe, the esterase isozyme (EST), superoxide dismutase (SOD) isozymes, and genome-specific random amplified polymorphic DNA (RAPD) markers were used to analyze for 14 Leymus species, together with two Psathyrostachys species (Ns), three Pseudoroegneria species (St), two Hordeum species (H), Lophopyrum elongatum (E^e), Australopyrum retrofractum (W), and Agropyron cristatum (P). The data were used to construct dendrograms by means of UPGMA in the NTSYS-pc computer program. The results suggested that (1) isozyme analysis can be used in the systematic studies of these perennial Triticeae; (2) there is a close relationship between Leymus, Psathyrostachys juncea, three Pseudoroegneria species, and Lophopyrum elongatum; (3) the Ns genome-specific RAPD marker was present in all 14 polyploid species of Leymus, while the E^e and P genome-specific RAPD markers were absent in 14 polyploid species of Leymus; the St, W and H genome-specific RAPD markers were present in some species of Leymus; (4) Leymus species have multiple origins, and different Leymus species derived their genomes from different donors.     

A barcode analysis of the genus Lobophora (Dictyotales,Phaeophyceae) in the western Atlantic Ocean with four novel species and the epitypification of L. variegata (J.V. Lamouroux) E.C. Oliveira

In the western Atlantic Ocean, the brown algal genus Lobophora is currently represented by a single species, L. variegata, with a type locality designated by Lamouroux as ‘Antilles’. In this study, we used molecular-assisted alpha taxonomy (MAAT) to assess species diversity of Lobophora in Bermuda, the Florida Keys, St. Croix and Guadeloupe (Lesser Antilles). Using cox1 and cox3 sequences as barcode markers, five species of Lobophora, four of them novel, were delineated, all previously having been identified in the area as L. variegata. Our morphological and habitat studies, made possible by abundant sampling, have revealed unique characters for each of these western Atlantic species, including distinct cellular arrangements, as well as different depth ranges for certain species. Observations made from Lamouroux’s holotype of Dictyota variegata (= Lobophora variegata) allowed us to assess the anatomy of this species, which enabled us to easily align this early taxon to one of our genetic species from the western Atlantic. As the type was unavailable for genetic analysis, we selected a recent St. Croix (Virgin Is., Antilles) specimen as the epitype to support it with molecular sequence data.     

The genus Gottschelia Grolle (Jungermanniopsida,Lophoziaceae) in China,with a description of G. grollei,sp. nov.

Abstract

The genus Gottschelia Grolle is reported as new to mainland China, from Yunnan Province. Previously G. schizopleura (Spruce) Grolle was the only known Chinese species, reported from Taiwan. However, two further species have recently been found in the Gaoligong Shan range, Yunnan Province, G. patoniae Grolle, Schill & D.G. Long, previously known from the East Himalaya of Nepal and India (Sikkim) and G. grollei D.G. Long & Váňa, described here as a new species endemic to China, the fourth known species in the genus. The differences between the three Chinese species are enumerated with notes on distribution and ecology.     

Evolution of St Helena arborescent Astereae (Asteraceae): relationships of the genera Commidendrum and Melanodendron

The cladistic relationships of endemic Commidendrum (four species) and Melanodendron (one species) from St Helena were inferred from sequences of ITS1 and ITS2 of nuclear ribosomal DNA. Despite showing a range of morphological and ecological variation, the four species of Commidendrum , C. spurium , C. robustum , C. rotundifolium , and C. rugosum , form a closely related monophyletic group with percentage sequence divergence between 0.2 and 0.9%. Melanodendron integrifolium is sister to Commidendrum indicating that the two genera may have evolved from a common ancestor that arrived in St Helena via a single dispersal event. The closest relatives of Commidendrum and Melanodendron appear to be South African, in the predominantly shrubby genus Felicia , although further sampling of South African Astereae is required. We discuss the evolution and adaptive radiation of these rare and threatened species with particular reference to the possible role of heterochrony.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 69–83.     

Redescription of Mymarilla Westwood,new synonymies under Cremnomymar Ogloblin (Hymenoptera,Mymaridae) and discussion of unusual wings

The monotypic genus Mymarilla Westwood is known only from St. Helena, a remote island in the South Atlantic Ocean. The peculiar species M. wollastoni Westwood (Mymaridae) is redescribed and illustrated from non-type material. Mymarilla is compared with Cremnomymar Ogloblinspp. from the Juan Fernández Islands in the South Pacific Ocean. Stephanodes Enock is shown to be the most likely sister genus to Mymarilla. Nesopolynema Ogloblin, syn. n., Oncomymar Ogloblin, syn. n., Scolopsopteron Ogloblin, syn. n., are placed in synonymy under Cremnomymar and their species transferred as Cremnomymar caudatum (Ogloblin 1952), comb. n., C. dipteron (Ogloblin 1957), comb. n., and C. kuscheli (Ogloblin 1952), comb. n. Wing shape and wing reductions in Mymaridae are discussed in relation to biogeography, particularly with respect island faunas and to four genera, Cremnomymar, Mymarilla, Parapolynema Fidalgo, and Richteria Girault, some or all of whose species have more or less convex fore wings.